_ Git - rust-lightning/blob - lightning/src/routing/router.rs

   1 // This file is Copyright its original authors, visible in version control
   2 // history.
   3 //
   4 // This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
   5 // or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   6 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
   7 // You may not use this file except in accordance with one or both of these
   8 // licenses.
   9
  10 //! The top-level routing/network map tracking logic lives here.
  11 //!
  12 //! You probably want to create a NetGraphMsgHandler and use that as your RoutingMessageHandler and then
  13 //! interrogate it to get routes for your own payments.
  14
  15 use bitcoin::secp256k1::key::PublicKey;
  16
  17 use ln::channelmanager::ChannelDetails;
  18 use ln::features::{ChannelFeatures, InvoiceFeatures, NodeFeatures};
  19 use ln::msgs::{DecodeError, ErrorAction, LightningError, MAX_VALUE_MSAT};
  20 use routing;
  21 use routing::network_graph::{NetworkGraph, NodeId, RoutingFees};
  22 use util::ser::{Writeable, Readable};
  23 use util::logger::{Level, Logger};
  24
  25 use io;
  26 use prelude::*;
  27 use alloc::collections::BinaryHeap;
  28 use core::cmp;
  29 use core::ops::Deref;
  30
  31 /// A hop in a route
  32 #[derive(Clone, Debug, Hash, PartialEq, Eq)]
  33 pub struct RouteHop {
  34         /// The node_id of the node at this hop.
  35         pub pubkey: PublicKey,
  36         /// The node_announcement features of the node at this hop. For the last hop, these may be
  37         /// amended to match the features present in the invoice this node generated.
  38         pub node_features: NodeFeatures,
  39         /// The channel that should be used from the previous hop to reach this node.
  40         pub short_channel_id: u64,
  41         /// The channel_announcement features of the channel that should be used from the previous hop
  42         /// to reach this node.
  43         pub channel_features: ChannelFeatures,
  44         /// The fee taken on this hop (for paying for the use of the *next* channel in the path).
  45         /// For the last hop, this should be the full value of the payment (might be more than
  46         /// requested if we had to match htlc_minimum_msat).
  47         pub fee_msat: u64,
  48         /// The CLTV delta added for this hop. For the last hop, this should be the full CLTV value
  49         /// expected at the destination, in excess of the current block height.
  50         pub cltv_expiry_delta: u32,
  51 }
  52
  53 impl_writeable_tlv_based!(RouteHop, {
  54         (0, pubkey, required),
  55         (2, node_features, required),
  56         (4, short_channel_id, required),
  57         (6, channel_features, required),
  58         (8, fee_msat, required),
  59         (10, cltv_expiry_delta, required),
  60 });
  61
  62 /// A route directs a payment from the sender (us) to the recipient. If the recipient supports MPP,
  63 /// it can take multiple paths. Each path is composed of one or more hops through the network.
  64 #[derive(Clone, Hash, PartialEq, Eq)]
  65 pub struct Route {
  66         /// The list of routes taken for a single (potentially-)multi-part payment. The pubkey of the
  67         /// last RouteHop in each path must be the same.
  68         /// Each entry represents a list of hops, NOT INCLUDING our own, where the last hop is the
  69         /// destination. Thus, this must always be at least length one. While the maximum length of any
  70         /// given path is variable, keeping the length of any path to less than 20 should currently
  71         /// ensure it is viable.
  72         pub paths: Vec<Vec<RouteHop>>,
  73 }
  74
  75 impl Route {
  76         /// Returns the total amount of fees paid on this [`Route`].
  77         ///
  78         /// This doesn't include any extra payment made to the recipient, which can happen in excess of
  79         /// the amount passed to [`get_route`]'s `final_value_msat`.
  80         pub fn get_total_fees(&self) -> u64 {
  81                 // Do not count last hop of each path since that's the full value of the payment
  82                 return self.paths.iter()
  83                         .flat_map(|path| path.split_last().map(|(_, path_prefix)| path_prefix).unwrap_or(&[]))
  84                         .map(|hop| &hop.fee_msat)
  85                         .sum();
  86         }
  87
  88         /// Returns the total amount paid on this [`Route`], excluding the fees.
  89         pub fn get_total_amount(&self) -> u64 {
  90                 return self.paths.iter()
  91                         .map(|path| path.split_last().map(|(hop, _)| hop.fee_msat).unwrap_or(0))
  92                         .sum();
  93         }
  94 }
  95
  96 const SERIALIZATION_VERSION: u8 = 1;
  97 const MIN_SERIALIZATION_VERSION: u8 = 1;
  98
  99 impl Writeable for Route {
 100         fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
 101                 write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
 102                 (self.paths.len() as u64).write(writer)?;
 103                 for hops in self.paths.iter() {
 104                         (hops.len() as u8).write(writer)?;
 105                         for hop in hops.iter() {
 106                                 hop.write(writer)?;
 107                         }
 108                 }
 109                 write_tlv_fields!(writer, {});
 110                 Ok(())
 111         }
 112 }
 113
 114 impl Readable for Route {
 115         fn read<R: io::Read>(reader: &mut R) -> Result<Route, DecodeError> {
 116                 let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 117                 let path_count: u64 = Readable::read(reader)?;
 118                 let mut paths = Vec::with_capacity(cmp::min(path_count, 128) as usize);
 119                 for _ in 0..path_count {
 120                         let hop_count: u8 = Readable::read(reader)?;
 121                         let mut hops = Vec::with_capacity(hop_count as usize);
 122                         for _ in 0..hop_count {
 123                                 hops.push(Readable::read(reader)?);
 124                         }
 125                         paths.push(hops);
 126                 }
 127                 read_tlv_fields!(reader, {});
 128                 Ok(Route { paths })
 129         }
 130 }
 131
 132 /// A list of hops along a payment path terminating with a channel to the recipient.
 133 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
 134 pub struct RouteHint(pub Vec<RouteHintHop>);
 135
 136 /// A channel descriptor for a hop along a payment path.
 137 #[derive(Clone, Debug, Hash, Eq, PartialEq)]
 138 pub struct RouteHintHop {
 139         /// The node_id of the non-target end of the route
 140         pub src_node_id: PublicKey,
 141         /// The short_channel_id of this channel
 142         pub short_channel_id: u64,
 143         /// The fees which must be paid to use this channel
 144         pub fees: RoutingFees,
 145         /// The difference in CLTV values between this node and the next node.
 146         pub cltv_expiry_delta: u16,
 147         /// The minimum value, in msat, which must be relayed to the next hop.
 148         pub htlc_minimum_msat: Option<u64>,
 149         /// The maximum value in msat available for routing with a single HTLC.
 150         pub htlc_maximum_msat: Option<u64>,
 151 }
 152
 153 #[derive(Eq, PartialEq)]
 154 struct RouteGraphNode {
 155         node_id: NodeId,
 156         lowest_fee_to_peer_through_node: u64,
 157         lowest_fee_to_node: u64,
 158         // The maximum value a yet-to-be-constructed payment path might flow through this node.
 159         // This value is upper-bounded by us by:
 160         // - how much is needed for a path being constructed
 161         // - how much value can channels following this node (up to the destination) can contribute,
 162         //   considering their capacity and fees
 163         value_contribution_msat: u64,
 164         /// The effective htlc_minimum_msat at this hop. If a later hop on the path had a higher HTLC
 165         /// minimum, we use it, plus the fees required at each earlier hop to meet it.
 166         path_htlc_minimum_msat: u64,
 167         /// All penalties incurred from this hop on the way to the destination, as calculated using
 168         /// channel scoring.
 169         path_penalty_msat: u64,
 170 }
 171
 172 impl cmp::Ord for RouteGraphNode {
 173         fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
 174                 let other_score = cmp::max(other.lowest_fee_to_peer_through_node, other.path_htlc_minimum_msat)
 175                         .checked_add(other.path_penalty_msat)
 176                         .unwrap_or_else(|| u64::max_value());
 177                 let self_score = cmp::max(self.lowest_fee_to_peer_through_node, self.path_htlc_minimum_msat)
 178                         .checked_add(self.path_penalty_msat)
 179                         .unwrap_or_else(|| u64::max_value());
 180                 other_score.cmp(&self_score).then_with(|| other.node_id.cmp(&self.node_id))
 181         }
 182 }
 183
 184 impl cmp::PartialOrd for RouteGraphNode {
 185         fn partial_cmp(&self, other: &RouteGraphNode) -> Option<cmp::Ordering> {
 186                 Some(self.cmp(other))
 187         }
 188 }
 189
 190 struct DummyDirectionalChannelInfo {
 191         cltv_expiry_delta: u32,
 192         htlc_minimum_msat: u64,
 193         htlc_maximum_msat: Option<u64>,
 194         fees: RoutingFees,
 195 }
 196
 197 /// It's useful to keep track of the hops associated with the fees required to use them,
 198 /// so that we can choose cheaper paths (as per Dijkstra's algorithm).
 199 /// Fee values should be updated only in the context of the whole path, see update_value_and_recompute_fees.
 200 /// These fee values are useful to choose hops as we traverse the graph "payee-to-payer".
 201 #[derive(Clone, Debug)]
 202 struct PathBuildingHop<'a> {
 203         // The RouteHintHop fields which will eventually be used if this hop is used in a final Route.
 204         // Note that node_features is calculated separately after our initial graph walk.
 205         node_id: NodeId,
 206         short_channel_id: u64,
 207         channel_features: &'a ChannelFeatures,
 208         fee_msat: u64,
 209         cltv_expiry_delta: u32,
 210
 211         /// Minimal fees required to route to the source node of the current hop via any of its inbound channels.
 212         src_lowest_inbound_fees: RoutingFees,
 213         /// Fees of the channel used in this hop.
 214         channel_fees: RoutingFees,
 215         /// All the fees paid *after* this channel on the way to the destination
 216         next_hops_fee_msat: u64,
 217         /// Fee paid for the use of the current channel (see channel_fees).
 218         /// The value will be actually deducted from the counterparty balance on the previous link.
 219         hop_use_fee_msat: u64,
 220         /// Used to compare channels when choosing the for routing.
 221         /// Includes paying for the use of a hop and the following hops, as well as
 222         /// an estimated cost of reaching this hop.
 223         /// Might get stale when fees are recomputed. Primarily for internal use.
 224         total_fee_msat: u64,
 225         /// This is useful for update_value_and_recompute_fees to make sure
 226         /// we don't fall below the minimum. Should not be updated manually and
 227         /// generally should not be accessed.
 228         htlc_minimum_msat: u64,
 229         /// A mirror of the same field in RouteGraphNode. Note that this is only used during the graph
 230         /// walk and may be invalid thereafter.
 231         path_htlc_minimum_msat: u64,
 232         /// All penalties incurred from this channel on the way to the destination, as calculated using
 233         /// channel scoring.
 234         path_penalty_msat: u64,
 235         /// If we've already processed a node as the best node, we shouldn't process it again. Normally
 236         /// we'd just ignore it if we did as all channels would have a higher new fee, but because we
 237         /// may decrease the amounts in use as we walk the graph, the actual calculated fee may
 238         /// decrease as well. Thus, we have to explicitly track which nodes have been processed and
 239         /// avoid processing them again.
 240         was_processed: bool,
 241         #[cfg(any(test, feature = "fuzztarget"))]
 242         // In tests, we apply further sanity checks on cases where we skip nodes we already processed
 243         // to ensure it is specifically in cases where the fee has gone down because of a decrease in
 244         // value_contribution_msat, which requires tracking it here. See comments below where it is
 245         // used for more info.
 246         value_contribution_msat: u64,
 247 }
 248
 249 // Instantiated with a list of hops with correct data in them collected during path finding,
 250 // an instance of this struct should be further modified only via given methods.
 251 #[derive(Clone)]
 252 struct PaymentPath<'a> {
 253         hops: Vec<(PathBuildingHop<'a>, NodeFeatures)>,
 254 }
 255
 256 impl<'a> PaymentPath<'a> {
 257         // TODO: Add a value_msat field to PaymentPath and use it instead of this function.
 258         fn get_value_msat(&self) -> u64 {
 259                 self.hops.last().unwrap().0.fee_msat
 260         }
 261
 262         fn get_total_fee_paid_msat(&self) -> u64 {
 263                 if self.hops.len() < 1 {
 264                         return 0;
 265                 }
 266                 let mut result = 0;
 267                 // Can't use next_hops_fee_msat because it gets outdated.
 268                 for (i, (hop, _)) in self.hops.iter().enumerate() {
 269                         if i != self.hops.len() - 1 {
 270                                 result += hop.fee_msat;
 271                         }
 272                 }
 273                 return result;
 274         }
 275
 276         // If the amount transferred by the path is updated, the fees should be adjusted. Any other way
 277         // to change fees may result in an inconsistency.
 278         //
 279         // Sometimes we call this function right after constructing a path which is inconsistent in
 280         // that it the value being transferred has decreased while we were doing path finding, leading
 281         // to the fees being paid not lining up with the actual limits.
 282         //
 283         // Note that this function is not aware of the available_liquidity limit, and thus does not
 284         // support increasing the value being transferred.
 285         fn update_value_and_recompute_fees(&mut self, value_msat: u64) {
 286                 assert!(value_msat <= self.hops.last().unwrap().0.fee_msat);
 287
 288                 let mut total_fee_paid_msat = 0 as u64;
 289                 for i in (0..self.hops.len()).rev() {
 290                         let last_hop = i == self.hops.len() - 1;
 291
 292                         // For non-last-hop, this value will represent the fees paid on the current hop. It
 293                         // will consist of the fees for the use of the next hop, and extra fees to match
 294                         // htlc_minimum_msat of the current channel. Last hop is handled separately.
 295                         let mut cur_hop_fees_msat = 0;
 296                         if !last_hop {
 297                                 cur_hop_fees_msat = self.hops.get(i + 1).unwrap().0.hop_use_fee_msat;
 298                         }
 299
 300                         let mut cur_hop = &mut self.hops.get_mut(i).unwrap().0;
 301                         cur_hop.next_hops_fee_msat = total_fee_paid_msat;
 302                         // Overpay in fees if we can't save these funds due to htlc_minimum_msat.
 303                         // We try to account for htlc_minimum_msat in scoring (add_entry!), so that nodes don't
 304                         // set it too high just to maliciously take more fees by exploiting this
 305                         // match htlc_minimum_msat logic.
 306                         let mut cur_hop_transferred_amount_msat = total_fee_paid_msat + value_msat;
 307                         if let Some(extra_fees_msat) = cur_hop.htlc_minimum_msat.checked_sub(cur_hop_transferred_amount_msat) {
 308                                 // Note that there is a risk that *previous hops* (those closer to us, as we go
 309                                 // payee->our_node here) would exceed their htlc_maximum_msat or available balance.
 310                                 //
 311                                 // This might make us end up with a broken route, although this should be super-rare
 312                                 // in practice, both because of how healthy channels look like, and how we pick
 313                                 // channels in add_entry.
 314                                 // Also, this can't be exploited more heavily than *announce a free path and fail
 315                                 // all payments*.
 316                                 cur_hop_transferred_amount_msat += extra_fees_msat;
 317                                 total_fee_paid_msat += extra_fees_msat;
 318                                 cur_hop_fees_msat += extra_fees_msat;
 319                         }
 320
 321                         if last_hop {
 322                                 // Final hop is a special case: it usually has just value_msat (by design), but also
 323                                 // it still could overpay for the htlc_minimum_msat.
 324                                 cur_hop.fee_msat = cur_hop_transferred_amount_msat;
 325                         } else {
 326                                 // Propagate updated fees for the use of the channels to one hop back, where they
 327                                 // will be actually paid (fee_msat). The last hop is handled above separately.
 328                                 cur_hop.fee_msat = cur_hop_fees_msat;
 329                         }
 330
 331                         // Fee for the use of the current hop which will be deducted on the previous hop.
 332                         // Irrelevant for the first hop, as it doesn't have the previous hop, and the use of
 333                         // this channel is free for us.
 334                         if i != 0 {
 335                                 if let Some(new_fee) = compute_fees(cur_hop_transferred_amount_msat, cur_hop.channel_fees) {
 336                                         cur_hop.hop_use_fee_msat = new_fee;
 337                                         total_fee_paid_msat += new_fee;
 338                                 } else {
 339                                         // It should not be possible because this function is called only to reduce the
 340                                         // value. In that case, compute_fee was already called with the same fees for
 341                                         // larger amount and there was no overflow.
 342                                         unreachable!();
 343                                 }
 344                         }
 345                 }
 346         }
 347 }
 348
 349 fn compute_fees(amount_msat: u64, channel_fees: RoutingFees) -> Option<u64> {
 350         let proportional_fee_millions =
 351                 amount_msat.checked_mul(channel_fees.proportional_millionths as u64);
 352         if let Some(new_fee) = proportional_fee_millions.and_then(|part| {
 353                         (channel_fees.base_msat as u64).checked_add(part / 1_000_000) }) {
 354
 355                 Some(new_fee)
 356         } else {
 357                 // This function may be (indirectly) called without any verification,
 358                 // with channel_fees provided by a caller. We should handle it gracefully.
 359                 None
 360         }
 361 }
 362
 363 /// Gets a keysend route from us (payer) to the given target node (payee). This is needed because
 364 /// keysend payments do not have an invoice from which to pull the payee's supported features, which
 365 /// makes it tricky to otherwise supply the `payee_features` parameter of `get_route`.
 366 pub fn get_keysend_route<L: Deref, S: routing::Score>(
 367         our_node_pubkey: &PublicKey, network: &NetworkGraph, payee: &PublicKey,
 368         first_hops: Option<&[&ChannelDetails]>, last_hops: &[&RouteHint], final_value_msat: u64,
 369         final_cltv: u32, logger: L, scorer: &S
 370 ) -> Result<Route, LightningError>
 371 where L::Target: Logger {
 372         let invoice_features = InvoiceFeatures::for_keysend();
 373         get_route(
 374                 our_node_pubkey, network, payee, Some(invoice_features), first_hops, last_hops,
 375                 final_value_msat, final_cltv, logger, scorer
 376         )
 377 }
 378
 379 /// Gets a route from us (payer) to the given target node (payee).
 380 ///
 381 /// If the payee provided features in their invoice, they should be provided via payee_features.
 382 /// Without this, MPP will only be used if the payee's features are available in the network graph.
 383 ///
 384 /// Private routing paths between a public node and the target may be included in `last_hops`.
 385 /// Currently, only the last hop in each path is considered.
 386 ///
 387 /// If some channels aren't announced, it may be useful to fill in a first_hops with the
 388 /// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our
 389 /// view of our local channels (from net_graph_msg_handler) will be ignored, and only those
 390 /// in first_hops will be used.
 391 ///
 392 /// Panics if first_hops contains channels without short_channel_ids
 393 /// (ChannelManager::list_usable_channels will never include such channels).
 394 ///
 395 /// The fees on channels from us to next-hops are ignored (as they are assumed to all be
 396 /// equal), however the enabled/disabled bit on such channels as well as the
 397 /// htlc_minimum_msat/htlc_maximum_msat *are* checked as they may change based on the receiving node.
 398 pub fn get_route<L: Deref, S: routing::Score>(
 399         our_node_pubkey: &PublicKey, network: &NetworkGraph, payee: &PublicKey,
 400         payee_features: Option<InvoiceFeatures>, first_hops: Option<&[&ChannelDetails]>,
 401         last_hops: &[&RouteHint], final_value_msat: u64, final_cltv: u32, logger: L, scorer: &S
 402 ) -> Result<Route, LightningError>
 403 where L::Target: Logger {
 404         let payee_node_id = NodeId::from_pubkey(&payee);
 405         let our_node_id = NodeId::from_pubkey(&our_node_pubkey);
 406
 407         if payee_node_id == our_node_id {
 408                 return Err(LightningError{err: "Cannot generate a route to ourselves".to_owned(), action: ErrorAction::IgnoreError});
 409         }
 410
 411         if final_value_msat > MAX_VALUE_MSAT {
 412                 return Err(LightningError{err: "Cannot generate a route of more value than all existing satoshis".to_owned(), action: ErrorAction::IgnoreError});
 413         }
 414
 415         if final_value_msat == 0 {
 416                 return Err(LightningError{err: "Cannot send a payment of 0 msat".to_owned(), action: ErrorAction::IgnoreError});
 417         }
 418
 419         for route in last_hops.iter() {
 420                 for hop in &route.0 {
 421                         if hop.src_node_id == *payee {
 422                                 return Err(LightningError{err: "Last hop cannot have a payee as a source.".to_owned(), action: ErrorAction::IgnoreError});
 423                         }
 424                 }
 425         }
 426
 427         // The general routing idea is the following:
 428         // 1. Fill first/last hops communicated by the caller.
 429         // 2. Attempt to construct a path from payer to payee for transferring
 430         //    any ~sufficient (described later) value.
 431         //    If succeed, remember which channels were used and how much liquidity they have available,
 432         //    so that future paths don't rely on the same liquidity.
 433         // 3. Prooceed to the next step if:
 434         //    - we hit the recommended target value;
 435         //    - OR if we could not construct a new path. Any next attempt will fail too.
 436         //    Otherwise, repeat step 2.
 437         // 4. See if we managed to collect paths which aggregately are able to transfer target value
 438         //    (not recommended value). If yes, proceed. If not, fail routing.
 439         // 5. Randomly combine paths into routes having enough to fulfill the payment. (TODO: knapsack)
 440         // 6. Of all the found paths, select only those with the lowest total fee.
 441         // 7. The last path in every selected route is likely to be more than we need.
 442         //    Reduce its value-to-transfer and recompute fees.
 443         // 8. Choose the best route by the lowest total fee.
 444
 445         // As for the actual search algorithm,
 446         // we do a payee-to-payer pseudo-Dijkstra's sorting by each node's distance from the payee
 447         // plus the minimum per-HTLC fee to get from it to another node (aka "shitty pseudo-A*").
 448         //
 449         // We are not a faithful Dijkstra's implementation because we can change values which impact
 450         // earlier nodes while processing later nodes. Specifically, if we reach a channel with a lower
 451         // liquidity limit (via htlc_maximum_msat, on-chain capacity or assumed liquidity limits) then
 452         // the value we are currently attempting to send over a path, we simply reduce the value being
 453         // sent along the path for any hops after that channel. This may imply that later fees (which
 454         // we've already tabulated) are lower because a smaller value is passing through the channels
 455         // (and the proportional fee is thus lower). There isn't a trivial way to recalculate the
 456         // channels which were selected earlier (and which may still be used for other paths without a
 457         // lower liquidity limit), so we simply accept that some liquidity-limited paths may be
 458         // de-preferenced.
 459         //
 460         // One potentially problematic case for this algorithm would be if there are many
 461         // liquidity-limited paths which are liquidity-limited near the destination (ie early in our
 462         // graph walking), we may never find a path which is not liquidity-limited and has lower
 463         // proportional fee (and only lower absolute fee when considering the ultimate value sent).
 464         // Because we only consider paths with at least 5% of the total value being sent, the damage
 465         // from such a case should be limited, however this could be further reduced in the future by
 466         // calculating fees on the amount we wish to route over a path, ie ignoring the liquidity
 467         // limits for the purposes of fee calculation.
 468         //
 469         // Alternatively, we could store more detailed path information in the heap (targets, below)
 470         // and index the best-path map (dist, below) by node *and* HTLC limits, however that would blow
 471         // up the runtime significantly both algorithmically (as we'd traverse nodes multiple times)
 472         // and practically (as we would need to store dynamically-allocated path information in heap
 473         // objects, increasing malloc traffic and indirect memory access significantly). Further, the
 474         // results of such an algorithm would likely be biased towards lower-value paths.
 475         //
 476         // Further, we could return to a faithful Dijkstra's algorithm by rejecting paths with limits
 477         // outside of our current search value, running a path search more times to gather candidate
 478         // paths at different values. While this may be acceptable, further path searches may increase
 479         // runtime for little gain. Specifically, the current algorithm rather efficiently explores the
 480         // graph for candidate paths, calculating the maximum value which can realistically be sent at
 481         // the same time, remaining generic across different payment values.
 482         //
 483         // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff
 484         // to use as the A* heuristic beyond just the cost to get one node further than the current
 485         // one.
 486
 487         let network_graph = network.read_only();
 488         let network_channels = network_graph.channels();
 489         let network_nodes = network_graph.nodes();
 490         let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes
 491                 cltv_expiry_delta: 0,
 492                 htlc_minimum_msat: 0,
 493                 htlc_maximum_msat: None,
 494                 fees: RoutingFees {
 495                         base_msat: 0,
 496                         proportional_millionths: 0,
 497                 }
 498         };
 499
 500         // Allow MPP only if we have a features set from somewhere that indicates the payee supports
 501         // it. If the payee supports it they're supposed to include it in the invoice, so that should
 502         // work reliably.
 503         let allow_mpp = if let Some(features) = &payee_features {
 504                 features.supports_basic_mpp()
 505         } else if let Some(node) = network_nodes.get(&payee_node_id) {
 506                 if let Some(node_info) = node.announcement_info.as_ref() {
 507                         node_info.features.supports_basic_mpp()
 508                 } else { false }
 509         } else { false };
 510         log_trace!(logger, "Searching for a route from payer {} to payee {} {} MPP", our_node_pubkey, payee,
 511                 if allow_mpp { "with" } else { "without" });
 512
 513         // Step (1).
 514         // Prepare the data we'll use for payee-to-payer search by
 515         // inserting first hops suggested by the caller as targets.
 516         // Our search will then attempt to reach them while traversing from the payee node.
 517         let mut first_hop_targets: HashMap<_, Vec<(_, ChannelFeatures, _, NodeFeatures)>> =
 518                 HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
 519         if let Some(hops) = first_hops {
 520                 for chan in hops {
 521                         let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
 522                         if chan.counterparty.node_id == *our_node_pubkey {
 523                                 return Err(LightningError{err: "First hop cannot have our_node_pubkey as a destination.".to_owned(), action: ErrorAction::IgnoreError});
 524                         }
 525                         first_hop_targets.entry(NodeId::from_pubkey(&chan.counterparty.node_id)).or_insert(Vec::new())
 526                                 .push((short_channel_id, chan.counterparty.features.to_context(), chan.outbound_capacity_msat, chan.counterparty.features.to_context()));
 527                 }
 528                 if first_hop_targets.is_empty() {
 529                         return Err(LightningError{err: "Cannot route when there are no outbound routes away from us".to_owned(), action: ErrorAction::IgnoreError});
 530                 }
 531         }
 532
 533         let empty_channel_features = ChannelFeatures::empty();
 534
 535         // The main heap containing all candidate next-hops sorted by their score (max(A* fee,
 536         // htlc_minimum)). Ideally this would be a heap which allowed cheap score reduction instead of
 537         // adding duplicate entries when we find a better path to a given node.
 538         let mut targets = BinaryHeap::new();
 539
 540         // Map from node_id to information about the best current path to that node, including feerate
 541         // information.
 542         let mut dist = HashMap::with_capacity(network_nodes.len());
 543
 544         // During routing, if we ignore a path due to an htlc_minimum_msat limit, we set this,
 545         // indicating that we may wish to try again with a higher value, potentially paying to meet an
 546         // htlc_minimum with extra fees while still finding a cheaper path.
 547         let mut hit_minimum_limit;
 548
 549         // When arranging a route, we select multiple paths so that we can make a multi-path payment.
 550         // We start with a path_value of the exact amount we want, and if that generates a route we may
 551         // return it immediately. Otherwise, we don't stop searching for paths until we have 3x the
 552         // amount we want in total across paths, selecting the best subset at the end.
 553         const ROUTE_CAPACITY_PROVISION_FACTOR: u64 = 3;
 554         let recommended_value_msat = final_value_msat * ROUTE_CAPACITY_PROVISION_FACTOR as u64;
 555         let mut path_value_msat = final_value_msat;
 556
 557         // We don't want multiple paths (as per MPP) share liquidity of the same channels.
 558         // This map allows paths to be aware of the channel use by other paths in the same call.
 559         // This would help to make a better path finding decisions and not "overbook" channels.
 560         // It is unaware of the directions (except for `outbound_capacity_msat` in `first_hops`).
 561         let mut bookkeeped_channels_liquidity_available_msat = HashMap::with_capacity(network_nodes.len());
 562
 563         // Keeping track of how much value we already collected across other paths. Helps to decide:
 564         // - how much a new path should be transferring (upper bound);
 565         // - whether a channel should be disregarded because
 566         //   it's available liquidity is too small comparing to how much more we need to collect;
 567         // - when we want to stop looking for new paths.
 568         let mut already_collected_value_msat = 0;
 569
 570         log_trace!(logger, "Building path from {} (payee) to {} (us/payer) for value {} msat.", payee, our_node_pubkey, final_value_msat);
 571
 572         macro_rules! add_entry {
 573                 // Adds entry which goes from $src_node_id to $dest_node_id
 574                 // over the channel with id $chan_id with fees described in
 575                 // $directional_info.
 576                 // $next_hops_fee_msat represents the fees paid for using all the channel *after* this one,
 577                 // since that value has to be transferred over this channel.
 578                 // Returns whether this channel caused an update to `targets`.
 579                 ( $chan_id: expr, $src_node_id: expr, $dest_node_id: expr, $directional_info: expr, $capacity_sats: expr, $chan_features: expr, $next_hops_fee_msat: expr,
 580                    $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr ) => { {
 581                         // We "return" whether we updated the path at the end, via this:
 582                         let mut did_add_update_path_to_src_node = false;
 583                         // Channels to self should not be used. This is more of belt-and-suspenders, because in
 584                         // practice these cases should be caught earlier:
 585                         // - for regular channels at channel announcement (TODO)
 586                         // - for first and last hops early in get_route
 587                         if $src_node_id != $dest_node_id.clone() {
 588                                 let available_liquidity_msat = bookkeeped_channels_liquidity_available_msat.entry($chan_id.clone()).or_insert_with(|| {
 589                                         let mut initial_liquidity_available_msat = None;
 590                                         if let Some(capacity_sats) = $capacity_sats {
 591                                                 initial_liquidity_available_msat = Some(capacity_sats * 1000);
 592                                         }
 593
 594                                         if let Some(htlc_maximum_msat) = $directional_info.htlc_maximum_msat {
 595                                                 if let Some(available_msat) = initial_liquidity_available_msat {
 596                                                         initial_liquidity_available_msat = Some(cmp::min(available_msat, htlc_maximum_msat));
 597                                                 } else {
 598                                                         initial_liquidity_available_msat = Some(htlc_maximum_msat);
 599                                                 }
 600                                         }
 601
 602                                         match initial_liquidity_available_msat {
 603                                                 Some(available_msat) => available_msat,
 604                                                 // We assume channels with unknown balance have
 605                                                 // a capacity of 0.0025 BTC (or 250_000 sats).
 606                                                 None => 250_000 * 1000
 607                                         }
 608                                 });
 609
 610                                 // It is tricky to substract $next_hops_fee_msat from available liquidity here.
 611                                 // It may be misleading because we might later choose to reduce the value transferred
 612                                 // over these channels, and the channel which was insufficient might become sufficient.
 613                                 // Worst case: we drop a good channel here because it can't cover the high following
 614                                 // fees caused by one expensive channel, but then this channel could have been used
 615                                 // if the amount being transferred over this path is lower.
 616                                 // We do this for now, but this is a subject for removal.
 617                                 if let Some(available_value_contribution_msat) = available_liquidity_msat.checked_sub($next_hops_fee_msat) {
 618
 619                                         // Routing Fragmentation Mitigation heuristic:
 620                                         //
 621                                         // Routing fragmentation across many payment paths increases the overall routing
 622                                         // fees as you have irreducible routing fees per-link used (`fee_base_msat`).
 623                                         // Taking too many smaller paths also increases the chance of payment failure.
 624                                         // Thus to avoid this effect, we require from our collected links to provide
 625                                         // at least a minimal contribution to the recommended value yet-to-be-fulfilled.
 626                                         //
 627                                         // This requirement is currently 5% of the remaining-to-be-collected value.
 628                                         // This means as we successfully advance in our collection,
 629                                         // the absolute liquidity contribution is lowered,
 630                                         // thus increasing the number of potential channels to be selected.
 631
 632                                         // Derive the minimal liquidity contribution with a ratio of 20 (5%, rounded up)
 633                                         // or 100% if we're not allowed to do multipath payments.
 634                                         let minimal_value_contribution_msat: u64 = if allow_mpp {
 635                                                 (recommended_value_msat - already_collected_value_msat + 19) / 20
 636                                         } else {
 637                                                 final_value_msat
 638                                         };
 639                                         // Verify the liquidity offered by this channel complies to the minimal contribution.
 640                                         let contributes_sufficient_value = available_value_contribution_msat >= minimal_value_contribution_msat;
 641
 642                                         let value_contribution_msat = cmp::min(available_value_contribution_msat, $next_hops_value_contribution);
 643                                         // Includes paying fees for the use of the following channels.
 644                                         let amount_to_transfer_over_msat: u64 = match value_contribution_msat.checked_add($next_hops_fee_msat) {
 645                                                 Some(result) => result,
 646                                                 // Can't overflow due to how the values were computed right above.
 647                                                 None => unreachable!(),
 648                                         };
 649                                         #[allow(unused_comparisons)] // $next_hops_path_htlc_minimum_msat is 0 in some calls so rustc complains
 650                                         let over_path_minimum_msat = amount_to_transfer_over_msat >= $directional_info.htlc_minimum_msat &&
 651                                                 amount_to_transfer_over_msat >= $next_hops_path_htlc_minimum_msat;
 652
 653                                         // If HTLC minimum is larger than the amount we're going to transfer, we shouldn't
 654                                         // bother considering this channel.
 655                                         // Since we're choosing amount_to_transfer_over_msat as maximum possible, it can
 656                                         // be only reduced later (not increased), so this channel should just be skipped
 657                                         // as not sufficient.
 658                                         if !over_path_minimum_msat {
 659                                                 hit_minimum_limit = true;
 660                                         } else if contributes_sufficient_value {
 661                                                 // Note that low contribution here (limited by available_liquidity_msat)
 662                                                 // might violate htlc_minimum_msat on the hops which are next along the
 663                                                 // payment path (upstream to the payee). To avoid that, we recompute path
 664                                                 // path fees knowing the final path contribution after constructing it.
 665                                                 let path_htlc_minimum_msat = compute_fees($next_hops_path_htlc_minimum_msat, $directional_info.fees)
 666                                                         .and_then(|fee_msat| fee_msat.checked_add($next_hops_path_htlc_minimum_msat))
 667                                                         .map(|fee_msat| cmp::max(fee_msat, $directional_info.htlc_minimum_msat))
 668                                                         .unwrap_or_else(|| u64::max_value());
 669                                                 let hm_entry = dist.entry($src_node_id);
 670                                                 let old_entry = hm_entry.or_insert_with(|| {
 671                                                         // If there was previously no known way to access
 672                                                         // the source node (recall it goes payee-to-payer) of $chan_id, first add
 673                                                         // a semi-dummy record just to compute the fees to reach the source node.
 674                                                         // This will affect our decision on selecting $chan_id
 675                                                         // as a way to reach the $dest_node_id.
 676                                                         let mut fee_base_msat = u32::max_value();
 677                                                         let mut fee_proportional_millionths = u32::max_value();
 678                                                         if let Some(Some(fees)) = network_nodes.get(&$src_node_id).map(|node| node.lowest_inbound_channel_fees) {
 679                                                                 fee_base_msat = fees.base_msat;
 680                                                                 fee_proportional_millionths = fees.proportional_millionths;
 681                                                         }
 682                                                         PathBuildingHop {
 683                                                                 node_id: $dest_node_id.clone(),
 684                                                                 short_channel_id: 0,
 685                                                                 channel_features: $chan_features,
 686                                                                 fee_msat: 0,
 687                                                                 cltv_expiry_delta: 0,
 688                                                                 src_lowest_inbound_fees: RoutingFees {
 689                                                                         base_msat: fee_base_msat,
 690                                                                         proportional_millionths: fee_proportional_millionths,
 691                                                                 },
 692                                                                 channel_fees: $directional_info.fees,
 693                                                                 next_hops_fee_msat: u64::max_value(),
 694                                                                 hop_use_fee_msat: u64::max_value(),
 695                                                                 total_fee_msat: u64::max_value(),
 696                                                                 htlc_minimum_msat: $directional_info.htlc_minimum_msat,
 697                                                                 path_htlc_minimum_msat,
 698                                                                 path_penalty_msat: u64::max_value(),
 699                                                                 was_processed: false,
 700                                                                 #[cfg(any(test, feature = "fuzztarget"))]
 701                                                                 value_contribution_msat,
 702                                                         }
 703                                                 });
 704
 705                                                 #[allow(unused_mut)] // We only use the mut in cfg(test)
 706                                                 let mut should_process = !old_entry.was_processed;
 707                                                 #[cfg(any(test, feature = "fuzztarget"))]
 708                                                 {
 709                                                         // In test/fuzzing builds, we do extra checks to make sure the skipping
 710                                                         // of already-seen nodes only happens in cases we expect (see below).
 711                                                         if !should_process { should_process = true; }
 712                                                 }
 713
 714                                                 if should_process {
 715                                                         let mut hop_use_fee_msat = 0;
 716                                                         let mut total_fee_msat = $next_hops_fee_msat;
 717
 718                                                         // Ignore hop_use_fee_msat for channel-from-us as we assume all channels-from-us
 719                                                         // will have the same effective-fee
 720                                                         if $src_node_id != our_node_id {
 721                                                                 match compute_fees(amount_to_transfer_over_msat, $directional_info.fees) {
 722                                                                         // max_value means we'll always fail
 723                                                                         // the old_entry.total_fee_msat > total_fee_msat check
 724                                                                         None => total_fee_msat = u64::max_value(),
 725                                                                         Some(fee_msat) => {
 726                                                                                 hop_use_fee_msat = fee_msat;
 727                                                                                 total_fee_msat += hop_use_fee_msat;
 728                                                                                 // When calculating the lowest inbound fees to a node, we
 729                                                                                 // calculate fees here not based on the actual value we think
 730                                                                                 // will flow over this channel, but on the minimum value that
 731                                                                                 // we'll accept flowing over it. The minimum accepted value
 732                                                                                 // is a constant through each path collection run, ensuring
 733                                                                                 // consistent basis. Otherwise we may later find a
 734                                                                                 // different path to the source node that is more expensive,
 735                                                                                 // but which we consider to be cheaper because we are capacity
 736                                                                                 // constrained and the relative fee becomes lower.
 737                                                                                 match compute_fees(minimal_value_contribution_msat, old_entry.src_lowest_inbound_fees)
 738                                                                                                 .map(|a| a.checked_add(total_fee_msat)) {
 739                                                                                         Some(Some(v)) => {
 740                                                                                                 total_fee_msat = v;
 741                                                                                         },
 742                                                                                         _ => {
 743                                                                                                 total_fee_msat = u64::max_value();
 744                                                                                         }
 745                                                                                 };
 746                                                                         }
 747                                                                 }
 748                                                         }
 749
 750                                                         let path_penalty_msat = $next_hops_path_penalty_msat
 751                                                                 .checked_add(scorer.channel_penalty_msat($chan_id.clone()))
 752                                                                 .unwrap_or_else(|| u64::max_value());
 753                                                         let new_graph_node = RouteGraphNode {
 754                                                                 node_id: $src_node_id,
 755                                                                 lowest_fee_to_peer_through_node: total_fee_msat,
 756                                                                 lowest_fee_to_node: $next_hops_fee_msat as u64 + hop_use_fee_msat,
 757                                                                 value_contribution_msat: value_contribution_msat,
 758                                                                 path_htlc_minimum_msat,
 759                                                                 path_penalty_msat,
 760                                                         };
 761
 762                                                         // Update the way of reaching $src_node_id with the given $chan_id (from $dest_node_id),
 763                                                         // if this way is cheaper than the already known
 764                                                         // (considering the cost to "reach" this channel from the route destination,
 765                                                         // the cost of using this channel,
 766                                                         // and the cost of routing to the source node of this channel).
 767                                                         // Also, consider that htlc_minimum_msat_difference, because we might end up
 768                                                         // paying it. Consider the following exploit:
 769                                                         // we use 2 paths to transfer 1.5 BTC. One of them is 0-fee normal 1 BTC path,
 770                                                         // and for the other one we picked a 1sat-fee path with htlc_minimum_msat of
 771                                                         // 1 BTC. Now, since the latter is more expensive, we gonna try to cut it
 772                                                         // by 0.5 BTC, but then match htlc_minimum_msat by paying a fee of 0.5 BTC
 773                                                         // to this channel.
 774                                                         // Ideally the scoring could be smarter (e.g. 0.5*htlc_minimum_msat here),
 775                                                         // but it may require additional tracking - we don't want to double-count
 776                                                         // the fees included in $next_hops_path_htlc_minimum_msat, but also
 777                                                         // can't use something that may decrease on future hops.
 778                                                         let old_cost = cmp::max(old_entry.total_fee_msat, old_entry.path_htlc_minimum_msat)
 779                                                                 .checked_add(old_entry.path_penalty_msat)
 780                                                                 .unwrap_or_else(|| u64::max_value());
 781                                                         let new_cost = cmp::max(total_fee_msat, path_htlc_minimum_msat)
 782                                                                 .checked_add(path_penalty_msat)
 783                                                                 .unwrap_or_else(|| u64::max_value());
 784
 785                                                         if !old_entry.was_processed && new_cost < old_cost {
 786                                                                 targets.push(new_graph_node);
 787                                                                 old_entry.next_hops_fee_msat = $next_hops_fee_msat;
 788                                                                 old_entry.hop_use_fee_msat = hop_use_fee_msat;
 789                                                                 old_entry.total_fee_msat = total_fee_msat;
 790                                                                 old_entry.node_id = $dest_node_id.clone();
 791                                                                 old_entry.short_channel_id = $chan_id.clone();
 792                                                                 old_entry.channel_features = $chan_features;
 793                                                                 old_entry.fee_msat = 0; // This value will be later filled with hop_use_fee_msat of the following channel
 794                                                                 old_entry.cltv_expiry_delta = $directional_info.cltv_expiry_delta as u32;
 795                                                                 old_entry.channel_fees = $directional_info.fees;
 796                                                                 old_entry.htlc_minimum_msat = $directional_info.htlc_minimum_msat;
 797                                                                 old_entry.path_htlc_minimum_msat = path_htlc_minimum_msat;
 798                                                                 old_entry.path_penalty_msat = path_penalty_msat;
 799                                                                 #[cfg(any(test, feature = "fuzztarget"))]
 800                                                                 {
 801                                                                         old_entry.value_contribution_msat = value_contribution_msat;
 802                                                                 }
 803                                                                 did_add_update_path_to_src_node = true;
 804                                                         } else if old_entry.was_processed && new_cost < old_cost {
 805                                                                 #[cfg(any(test, feature = "fuzztarget"))]
 806                                                                 {
 807                                                                         // If we're skipping processing a node which was previously
 808                                                                         // processed even though we found another path to it with a
 809                                                                         // cheaper fee, check that it was because the second path we
 810                                                                         // found (which we are processing now) has a lower value
 811                                                                         // contribution due to an HTLC minimum limit.
 812                                                                         //
 813                                                                         // e.g. take a graph with two paths from node 1 to node 2, one
 814                                                                         // through channel A, and one through channel B. Channel A and
 815                                                                         // B are both in the to-process heap, with their scores set by
 816                                                                         // a higher htlc_minimum than fee.
 817                                                                         // Channel A is processed first, and the channels onwards from
 818                                                                         // node 1 are added to the to-process heap. Thereafter, we pop
 819                                                                         // Channel B off of the heap, note that it has a much more
 820                                                                         // restrictive htlc_maximum_msat, and recalculate the fees for
 821                                                                         // all of node 1's channels using the new, reduced, amount.
 822                                                                         //
 823                                                                         // This would be bogus - we'd be selecting a higher-fee path
 824                                                                         // with a lower htlc_maximum_msat instead of the one we'd
 825                                                                         // already decided to use.
 826                                                                         debug_assert!(path_htlc_minimum_msat < old_entry.path_htlc_minimum_msat);
 827                                                                         debug_assert!(
 828                                                                                 value_contribution_msat + path_penalty_msat <
 829                                                                                 old_entry.value_contribution_msat + old_entry.path_penalty_msat
 830                                                                         );
 831                                                                 }
 832                                                         }
 833                                                 }
 834                                         }
 835                                 }
 836                         }
 837                         did_add_update_path_to_src_node
 838                 } }
 839         }
 840
 841         let empty_node_features = NodeFeatures::empty();
 842         // Find ways (channels with destination) to reach a given node and store them
 843         // in the corresponding data structures (routing graph etc).
 844         // $fee_to_target_msat represents how much it costs to reach to this node from the payee,
 845         // meaning how much will be paid in fees after this node (to the best of our knowledge).
 846         // This data can later be helpful to optimize routing (pay lower fees).
 847         macro_rules! add_entries_to_cheapest_to_target_node {
 848                 ( $node: expr, $node_id: expr, $fee_to_target_msat: expr, $next_hops_value_contribution: expr, $next_hops_path_htlc_minimum_msat: expr, $next_hops_path_penalty_msat: expr ) => {
 849                         let skip_node = if let Some(elem) = dist.get_mut(&$node_id) {
 850                                 let was_processed = elem.was_processed;
 851                                 elem.was_processed = true;
 852                                 was_processed
 853                         } else {
 854                                 // Entries are added to dist in add_entry!() when there is a channel from a node.
 855                                 // Because there are no channels from payee, it will not have a dist entry at this point.
 856                                 // If we're processing any other node, it is always be the result of a channel from it.
 857                                 assert_eq!($node_id, payee_node_id);
 858                                 false
 859                         };
 860
 861                         if !skip_node {
 862                                 if let Some(first_channels) = first_hop_targets.get(&$node_id) {
 863                                         for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
 864                                                 add_entry!(first_hop, our_node_id, $node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat);
 865                                         }
 866                                 }
 867
 868                                 let features = if let Some(node_info) = $node.announcement_info.as_ref() {
 869                                         &node_info.features
 870                                 } else {
 871                                         &empty_node_features
 872                                 };
 873
 874                                 if !features.requires_unknown_bits() {
 875                                         for chan_id in $node.channels.iter() {
 876                                                 let chan = network_channels.get(chan_id).unwrap();
 877                                                 if !chan.features.requires_unknown_bits() {
 878                                                         if chan.node_one == $node_id {
 879                                                                 // ie $node is one, ie next hop in A* is two, via the two_to_one channel
 880                                                                 if first_hops.is_none() || chan.node_two != our_node_id {
 881                                                                         if let Some(two_to_one) = chan.two_to_one.as_ref() {
 882                                                                                 if two_to_one.enabled {
 883                                                                                         add_entry!(chan_id, chan.node_two, chan.node_one, two_to_one, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat);
 884                                                                                 }
 885                                                                         }
 886                                                                 }
 887                                                         } else {
 888                                                                 if first_hops.is_none() || chan.node_one != our_node_id{
 889                                                                         if let Some(one_to_two) = chan.one_to_two.as_ref() {
 890                                                                                 if one_to_two.enabled {
 891                                                                                         add_entry!(chan_id, chan.node_one, chan.node_two, one_to_two, chan.capacity_sats, &chan.features, $fee_to_target_msat, $next_hops_value_contribution, $next_hops_path_htlc_minimum_msat, $next_hops_path_penalty_msat);
 892                                                                                 }
 893                                                                         }
 894                                                                 }
 895                                                         }
 896                                                 }
 897                                         }
 898                                 }
 899                         }
 900                 };
 901         }
 902
 903         let mut payment_paths = Vec::<PaymentPath>::new();
 904
 905         // TODO: diversify by nodes (so that all paths aren't doomed if one node is offline).
 906         'paths_collection: loop {
 907                 // For every new path, start from scratch, except
 908                 // bookkeeped_channels_liquidity_available_msat, which will improve
 909                 // the further iterations of path finding. Also don't erase first_hop_targets.
 910                 targets.clear();
 911                 dist.clear();
 912                 hit_minimum_limit = false;
 913
 914                 // If first hop is a private channel and the only way to reach the payee, this is the only
 915                 // place where it could be added.
 916                 if let Some(first_channels) = first_hop_targets.get(&payee_node_id) {
 917                         for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
 918                                 let added = add_entry!(first_hop, our_node_id, payee_node_id, dummy_directional_info, Some(outbound_capacity_msat / 1000), features, 0, path_value_msat, 0, 0u64);
 919                                 log_trace!(logger, "{} direct route to payee via SCID {}", if added { "Added" } else { "Skipped" }, first_hop);
 920                         }
 921                 }
 922
 923                 // Add the payee as a target, so that the payee-to-payer
 924                 // search algorithm knows what to start with.
 925                 match network_nodes.get(&payee_node_id) {
 926                         // The payee is not in our network graph, so nothing to add here.
 927                         // There is still a chance of reaching them via last_hops though,
 928                         // so don't yet fail the payment here.
 929                         // If not, targets.pop() will not even let us enter the loop in step 2.
 930                         None => {},
 931                         Some(node) => {
 932                                 add_entries_to_cheapest_to_target_node!(node, payee_node_id, 0, path_value_msat, 0, 0u64);
 933                         },
 934                 }
 935
 936                 // Step (2).
 937                 // If a caller provided us with last hops, add them to routing targets. Since this happens
 938                 // earlier than general path finding, they will be somewhat prioritized, although currently
 939                 // it matters only if the fees are exactly the same.
 940                 for route in last_hops.iter().filter(|route| !route.0.is_empty()) {
 941                         let first_hop_in_route = &(route.0)[0];
 942                         let have_hop_src_in_graph =
 943                                 // Only add the hops in this route to our candidate set if either
 944                                 // we have a direct channel to the first hop or the first hop is
 945                                 // in the regular network graph.
 946                                 first_hop_targets.get(&NodeId::from_pubkey(&first_hop_in_route.src_node_id)).is_some() ||
 947                                 network_nodes.get(&NodeId::from_pubkey(&first_hop_in_route.src_node_id)).is_some();
 948                         if have_hop_src_in_graph {
 949                                 // We start building the path from reverse, i.e., from payee
 950                                 // to the first RouteHintHop in the path.
 951                                 let hop_iter = route.0.iter().rev();
 952                                 let prev_hop_iter = core::iter::once(payee).chain(
 953                                         route.0.iter().skip(1).rev().map(|hop| &hop.src_node_id));
 954                                 let mut hop_used = true;
 955                                 let mut aggregate_next_hops_fee_msat: u64 = 0;
 956                                 let mut aggregate_next_hops_path_htlc_minimum_msat: u64 = 0;
 957                                 let mut aggregate_next_hops_path_penalty_msat: u64 = 0;
 958
 959                                 for (idx, (hop, prev_hop_id)) in hop_iter.zip(prev_hop_iter).enumerate() {
 960                                         // BOLT 11 doesn't allow inclusion of features for the last hop hints, which
 961                                         // really sucks, cause we're gonna need that eventually.
 962                                         let hop_htlc_minimum_msat: u64 = hop.htlc_minimum_msat.unwrap_or(0);
 963
 964                                         let directional_info = DummyDirectionalChannelInfo {
 965                                                 cltv_expiry_delta: hop.cltv_expiry_delta as u32,
 966                                                 htlc_minimum_msat: hop_htlc_minimum_msat,
 967                                                 htlc_maximum_msat: hop.htlc_maximum_msat,
 968                                                 fees: hop.fees,
 969                                         };
 970
 971                                         let reqd_channel_cap = if let Some (val) = final_value_msat.checked_add(match idx {
 972                                                 0 => 999,
 973                                                 _ => aggregate_next_hops_fee_msat.checked_add(999).unwrap_or(u64::max_value())
 974                                         }) { Some( val / 1000 ) } else { break; }; // converting from msat or breaking if max ~ infinity
 975
 976                                         aggregate_next_hops_path_penalty_msat = aggregate_next_hops_path_penalty_msat
 977                                                 .checked_add(scorer.channel_penalty_msat(hop.short_channel_id))
 978                                                 .unwrap_or_else(|| u64::max_value());
 979
 980                                         // We assume that the recipient only included route hints for routes which had
 981                                         // sufficient value to route `final_value_msat`. Note that in the case of "0-value"
 982                                         // invoices where the invoice does not specify value this may not be the case, but
 983                                         // better to include the hints than not.
 984                                         if !add_entry!(hop.short_channel_id, NodeId::from_pubkey(&hop.src_node_id), NodeId::from_pubkey(&prev_hop_id), directional_info, reqd_channel_cap, &empty_channel_features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat) {
 985                                                 // If this hop was not used then there is no use checking the preceding hops
 986                                                 // in the RouteHint. We can break by just searching for a direct channel between
 987                                                 // last checked hop and first_hop_targets
 988                                                 hop_used = false;
 989                                         }
 990
 991                                         // Searching for a direct channel between last checked hop and first_hop_targets
 992                                         if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&prev_hop_id)) {
 993                                                 for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
 994                                                         add_entry!(first_hop, our_node_id , NodeId::from_pubkey(&prev_hop_id), dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat);
 995                                                 }
 996                                         }
 997
 998                                         if !hop_used {
 999                                                 break;
1000                                         }
1001
1002                                         // In the next values of the iterator, the aggregate fees already reflects
1003                                         // the sum of value sent from payer (final_value_msat) and routing fees
1004                                         // for the last node in the RouteHint. We need to just add the fees to
1005                                         // route through the current node so that the preceeding node (next iteration)
1006                                         // can use it.
1007                                         let hops_fee = compute_fees(aggregate_next_hops_fee_msat + final_value_msat, hop.fees)
1008                                                 .map_or(None, |inc| inc.checked_add(aggregate_next_hops_fee_msat));
1009                                         aggregate_next_hops_fee_msat = if let Some(val) = hops_fee { val } else { break; };
1010
1011                                         let hop_htlc_minimum_msat_inc = if let Some(val) = compute_fees(aggregate_next_hops_path_htlc_minimum_msat, hop.fees) { val } else { break; };
1012                                         let hops_path_htlc_minimum = aggregate_next_hops_path_htlc_minimum_msat
1013                                                 .checked_add(hop_htlc_minimum_msat_inc);
1014                                         aggregate_next_hops_path_htlc_minimum_msat = if let Some(val) = hops_path_htlc_minimum { cmp::max(hop_htlc_minimum_msat, val) } else { break; };
1015
1016                                         if idx == route.0.len() - 1 {
1017                                                 // The last hop in this iterator is the first hop in
1018                                                 // overall RouteHint.
1019                                                 // If this hop connects to a node with which we have a direct channel,
1020                                                 // ignore the network graph and, if the last hop was added, add our
1021                                                 // direct channel to the candidate set.
1022                                                 //
1023                                                 // Note that we *must* check if the last hop was added as `add_entry`
1024                                                 // always assumes that the third argument is a node to which we have a
1025                                                 // path.
1026                                                 if let Some(first_channels) = first_hop_targets.get(&NodeId::from_pubkey(&hop.src_node_id)) {
1027                                                         for (ref first_hop, ref features, ref outbound_capacity_msat, _) in first_channels {
1028                                                                 add_entry!(first_hop, our_node_id , NodeId::from_pubkey(&hop.src_node_id), dummy_directional_info, Some(outbound_capacity_msat / 1000), features, aggregate_next_hops_fee_msat, path_value_msat, aggregate_next_hops_path_htlc_minimum_msat, aggregate_next_hops_path_penalty_msat);
1029                                                         }
1030                                                 }
1031                                         }
1032                                 }
1033                         }
1034                 }
1035
1036                 log_trace!(logger, "Starting main path collection loop with {} nodes pre-filled from first/last hops.", targets.len());
1037
1038                 // At this point, targets are filled with the data from first and
1039                 // last hops communicated by the caller, and the payment receiver.
1040                 let mut found_new_path = false;
1041
1042                 // Step (3).
1043                 // If this loop terminates due the exhaustion of targets, two situations are possible:
1044                 // - not enough outgoing liquidity:
1045                 //   0 < already_collected_value_msat < final_value_msat
1046                 // - enough outgoing liquidity:
1047                 //   final_value_msat <= already_collected_value_msat < recommended_value_msat
1048                 // Both these cases (and other cases except reaching recommended_value_msat) mean that
1049                 // paths_collection will be stopped because found_new_path==false.
1050                 // This is not necessarily a routing failure.
1051                 'path_construction: while let Some(RouteGraphNode { node_id, lowest_fee_to_node, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat, .. }) = targets.pop() {
1052
1053                         // Since we're going payee-to-payer, hitting our node as a target means we should stop
1054                         // traversing the graph and arrange the path out of what we found.
1055                         if node_id == our_node_id {
1056                                 let mut new_entry = dist.remove(&our_node_id).unwrap();
1057                                 let mut ordered_hops = vec!((new_entry.clone(), NodeFeatures::empty()));
1058
1059                                 'path_walk: loop {
1060                                         let mut features_set = false;
1061                                         if let Some(first_channels) = first_hop_targets.get(&ordered_hops.last().unwrap().0.node_id) {
1062                                                 for (scid, _, _, ref features) in first_channels {
1063                                                         if *scid == ordered_hops.last().unwrap().0.short_channel_id {
1064                                                                 ordered_hops.last_mut().unwrap().1 = features.clone();
1065                                                                 features_set = true;
1066                                                                 break;
1067                                                         }
1068                                                 }
1069                                         }
1070                                         if !features_set {
1071                                                 if let Some(node) = network_nodes.get(&ordered_hops.last().unwrap().0.node_id) {
1072                                                         if let Some(node_info) = node.announcement_info.as_ref() {
1073                                                                 ordered_hops.last_mut().unwrap().1 = node_info.features.clone();
1074                                                         } else {
1075                                                                 ordered_hops.last_mut().unwrap().1 = NodeFeatures::empty();
1076                                                         }
1077                                                 } else {
1078                                                         // We should be able to fill in features for everything except the last
1079                                                         // hop, if the last hop was provided via a BOLT 11 invoice (though we
1080                                                         // should be able to extend it further as BOLT 11 does have feature
1081                                                         // flags for the last hop node itself).
1082                                                         assert!(ordered_hops.last().unwrap().0.node_id == payee_node_id);
1083                                                 }
1084                                         }
1085
1086                                         // Means we succesfully traversed from the payer to the payee, now
1087                                         // save this path for the payment route. Also, update the liquidity
1088                                         // remaining on the used hops, so that we take them into account
1089                                         // while looking for more paths.
1090                                         if ordered_hops.last().unwrap().0.node_id == payee_node_id {
1091                                                 break 'path_walk;
1092                                         }
1093
1094                                         new_entry = match dist.remove(&ordered_hops.last().unwrap().0.node_id) {
1095                                                 Some(payment_hop) => payment_hop,
1096                                                 // We can't arrive at None because, if we ever add an entry to targets,
1097                                                 // we also fill in the entry in dist (see add_entry!).
1098                                                 None => unreachable!(),
1099                                         };
1100                                         // We "propagate" the fees one hop backward (topologically) here,
1101                                         // so that fees paid for a HTLC forwarding on the current channel are
1102                                         // associated with the previous channel (where they will be subtracted).
1103                                         ordered_hops.last_mut().unwrap().0.fee_msat = new_entry.hop_use_fee_msat;
1104                                         ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = new_entry.cltv_expiry_delta;
1105                                         ordered_hops.push((new_entry.clone(), NodeFeatures::empty()));
1106                                 }
1107                                 ordered_hops.last_mut().unwrap().0.fee_msat = value_contribution_msat;
1108                                 ordered_hops.last_mut().unwrap().0.hop_use_fee_msat = 0;
1109                                 ordered_hops.last_mut().unwrap().0.cltv_expiry_delta = final_cltv;
1110
1111                                 log_trace!(logger, "Found a path back to us from the target with {} hops contributing up to {} msat: {:?}",
1112                                         ordered_hops.len(), value_contribution_msat, ordered_hops);
1113
1114                                 let mut payment_path = PaymentPath {hops: ordered_hops};
1115
1116                                 // We could have possibly constructed a slightly inconsistent path: since we reduce
1117                                 // value being transferred along the way, we could have violated htlc_minimum_msat
1118                                 // on some channels we already passed (assuming dest->source direction). Here, we
1119                                 // recompute the fees again, so that if that's the case, we match the currently
1120                                 // underpaid htlc_minimum_msat with fees.
1121                                 payment_path.update_value_and_recompute_fees(cmp::min(value_contribution_msat, final_value_msat));
1122
1123                                 // Since a path allows to transfer as much value as
1124                                 // the smallest channel it has ("bottleneck"), we should recompute
1125                                 // the fees so sender HTLC don't overpay fees when traversing
1126                                 // larger channels than the bottleneck. This may happen because
1127                                 // when we were selecting those channels we were not aware how much value
1128                                 // this path will transfer, and the relative fee for them
1129                                 // might have been computed considering a larger value.
1130                                 // Remember that we used these channels so that we don't rely
1131                                 // on the same liquidity in future paths.
1132                                 let mut prevented_redundant_path_selection = false;
1133                                 for (payment_hop, _) in payment_path.hops.iter() {
1134                                         let channel_liquidity_available_msat = bookkeeped_channels_liquidity_available_msat.get_mut(&payment_hop.short_channel_id).unwrap();
1135                                         let mut spent_on_hop_msat = value_contribution_msat;
1136                                         let next_hops_fee_msat = payment_hop.next_hops_fee_msat;
1137                                         spent_on_hop_msat += next_hops_fee_msat;
1138                                         if spent_on_hop_msat == *channel_liquidity_available_msat {
1139                                                 // If this path used all of this channel's available liquidity, we know
1140                                                 // this path will not be selected again in the next loop iteration.
1141                                                 prevented_redundant_path_selection = true;
1142                                         }
1143                                         *channel_liquidity_available_msat -= spent_on_hop_msat;
1144                                 }
1145                                 if !prevented_redundant_path_selection {
1146                                         // If we weren't capped by hitting a liquidity limit on a channel in the path,
1147                                         // we'll probably end up picking the same path again on the next iteration.
1148                                         // Decrease the available liquidity of a hop in the middle of the path.
1149                                         let victim_scid = payment_path.hops[(payment_path.hops.len() - 1) / 2].0.short_channel_id;
1150                                         log_trace!(logger, "Disabling channel {} for future path building iterations to avoid duplicates.", victim_scid);
1151                                         let victim_liquidity = bookkeeped_channels_liquidity_available_msat.get_mut(&victim_scid).unwrap();
1152                                         *victim_liquidity = 0;
1153                                 }
1154
1155                                 // Track the total amount all our collected paths allow to send so that we:
1156                                 // - know when to stop looking for more paths
1157                                 // - know which of the hops are useless considering how much more sats we need
1158                                 //   (contributes_sufficient_value)
1159                                 already_collected_value_msat += value_contribution_msat;
1160
1161                                 payment_paths.push(payment_path);
1162                                 found_new_path = true;
1163                                 break 'path_construction;
1164                         }
1165
1166                         // If we found a path back to the payee, we shouldn't try to process it again. This is
1167                         // the equivalent of the `elem.was_processed` check in
1168                         // add_entries_to_cheapest_to_target_node!() (see comment there for more info).
1169                         if node_id == payee_node_id { continue 'path_construction; }
1170
1171                         // Otherwise, since the current target node is not us,
1172                         // keep "unrolling" the payment graph from payee to payer by
1173                         // finding a way to reach the current target from the payer side.
1174                         match network_nodes.get(&node_id) {
1175                                 None => {},
1176                                 Some(node) => {
1177                                         add_entries_to_cheapest_to_target_node!(node, node_id, lowest_fee_to_node, value_contribution_msat, path_htlc_minimum_msat, path_penalty_msat);
1178                                 },
1179                         }
1180                 }
1181
1182                 if !allow_mpp {
1183                         // If we don't support MPP, no use trying to gather more value ever.
1184                         break 'paths_collection;
1185                 }
1186
1187                 // Step (4).
1188                 // Stop either when the recommended value is reached or if no new path was found in this
1189                 // iteration.
1190                 // In the latter case, making another path finding attempt won't help,
1191                 // because we deterministically terminated the search due to low liquidity.
1192                 if already_collected_value_msat >= recommended_value_msat || !found_new_path {
1193                         log_trace!(logger, "Have now collected {} msat (seeking {} msat) in paths. Last path loop {} a new path.",
1194                                 already_collected_value_msat, recommended_value_msat, if found_new_path { "found" } else { "did not find" });
1195                         break 'paths_collection;
1196                 } else if found_new_path && already_collected_value_msat == final_value_msat && payment_paths.len() == 1 {
1197                         // Further, if this was our first walk of the graph, and we weren't limited by an
1198                         // htlc_minimum_msat, return immediately because this path should suffice. If we were
1199                         // limited by an htlc_minimum_msat value, find another path with a higher value,
1200                         // potentially allowing us to pay fees to meet the htlc_minimum on the new path while
1201                         // still keeping a lower total fee than this path.
1202                         if !hit_minimum_limit {
1203                                 log_trace!(logger, "Collected exactly our payment amount on the first pass, without hitting an htlc_minimum_msat limit, exiting.");
1204                                 break 'paths_collection;
1205                         }
1206                         log_trace!(logger, "Collected our payment amount on the first pass, but running again to collect extra paths with a potentially higher limit.");
1207                         path_value_msat = recommended_value_msat;
1208                 }
1209         }
1210
1211         // Step (5).
1212         if payment_paths.len() == 0 {
1213                 return Err(LightningError{err: "Failed to find a path to the given destination".to_owned(), action: ErrorAction::IgnoreError});
1214         }
1215
1216         if already_collected_value_msat < final_value_msat {
1217                 return Err(LightningError{err: "Failed to find a sufficient route to the given destination".to_owned(), action: ErrorAction::IgnoreError});
1218         }
1219
1220         // Sort by total fees and take the best paths.
1221         payment_paths.sort_by_key(|path| path.get_total_fee_paid_msat());
1222         if payment_paths.len() > 50 {
1223                 payment_paths.truncate(50);
1224         }
1225
1226         // Draw multiple sufficient routes by randomly combining the selected paths.
1227         let mut drawn_routes = Vec::new();
1228         for i in 0..payment_paths.len() {
1229                 let mut cur_route = Vec::<PaymentPath>::new();
1230                 let mut aggregate_route_value_msat = 0;
1231
1232                 // Step (6).
1233                 // TODO: real random shuffle
1234                 // Currently just starts with i_th and goes up to i-1_th in a looped way.
1235                 let cur_payment_paths = [&payment_paths[i..], &payment_paths[..i]].concat();
1236
1237                 // Step (7).
1238                 for payment_path in cur_payment_paths {
1239                         cur_route.push(payment_path.clone());
1240                         aggregate_route_value_msat += payment_path.get_value_msat();
1241                         if aggregate_route_value_msat > final_value_msat {
1242                                 // Last path likely overpaid. Substract it from the most expensive
1243                                 // (in terms of proportional fee) path in this route and recompute fees.
1244                                 // This might be not the most economically efficient way, but fewer paths
1245                                 // also makes routing more reliable.
1246                                 let mut overpaid_value_msat = aggregate_route_value_msat - final_value_msat;
1247
1248                                 // First, drop some expensive low-value paths entirely if possible.
1249                                 // Sort by value so that we drop many really-low values first, since
1250                                 // fewer paths is better: the payment is less likely to fail.
1251                                 // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
1252                                 // so that the sender pays less fees overall. And also htlc_minimum_msat.
1253                                 cur_route.sort_by_key(|path| path.get_value_msat());
1254                                 // We should make sure that at least 1 path left.
1255                                 let mut paths_left = cur_route.len();
1256                                 cur_route.retain(|path| {
1257                                         if paths_left == 1 {
1258                                                 return true
1259                                         }
1260                                         let mut keep = true;
1261                                         let path_value_msat = path.get_value_msat();
1262                                         if path_value_msat <= overpaid_value_msat {
1263                                                 keep = false;
1264                                                 overpaid_value_msat -= path_value_msat;
1265                                                 paths_left -= 1;
1266                                         }
1267                                         keep
1268                                 });
1269
1270                                 if overpaid_value_msat == 0 {
1271                                         break;
1272                                 }
1273
1274                                 assert!(cur_route.len() > 0);
1275
1276                                 // Step (8).
1277                                 // Now, substract the overpaid value from the most-expensive path.
1278                                 // TODO: this could also be optimized by also sorting by feerate_per_sat_routed,
1279                                 // so that the sender pays less fees overall. And also htlc_minimum_msat.
1280                                 cur_route.sort_by_key(|path| { path.hops.iter().map(|hop| hop.0.channel_fees.proportional_millionths as u64).sum::<u64>() });
1281                                 let expensive_payment_path = cur_route.first_mut().unwrap();
1282                                 // We already dropped all the small channels above, meaning all the
1283                                 // remaining channels are larger than remaining overpaid_value_msat.
1284                                 // Thus, this can't be negative.
1285                                 let expensive_path_new_value_msat = expensive_payment_path.get_value_msat() - overpaid_value_msat;
1286                                 expensive_payment_path.update_value_and_recompute_fees(expensive_path_new_value_msat);
1287                                 break;
1288                         }
1289                 }
1290                 drawn_routes.push(cur_route);
1291         }
1292
1293         // Step (9).
1294         // Select the best route by lowest total fee.
1295         drawn_routes.sort_by_key(|paths| paths.iter().map(|path| path.get_total_fee_paid_msat()).sum::<u64>());
1296         let mut selected_paths = Vec::<Vec<Result<RouteHop, LightningError>>>::new();
1297         for payment_path in drawn_routes.first().unwrap() {
1298                 selected_paths.push(payment_path.hops.iter().map(|(payment_hop, node_features)| {
1299                         Ok(RouteHop {
1300                                 pubkey: PublicKey::from_slice(payment_hop.node_id.as_slice()).map_err(|_| LightningError{err: format!("Public key {:?} is invalid", &payment_hop.node_id), action: ErrorAction::IgnoreAndLog(Level::Trace)})?,
1301                                 node_features: node_features.clone(),
1302                                 short_channel_id: payment_hop.short_channel_id,
1303                                 channel_features: payment_hop.channel_features.clone(),
1304                                 fee_msat: payment_hop.fee_msat,
1305                                 cltv_expiry_delta: payment_hop.cltv_expiry_delta,
1306                         })
1307                 }).collect());
1308         }
1309
1310         if let Some(features) = &payee_features {
1311                 for path in selected_paths.iter_mut() {
1312                         if let Ok(route_hop) = path.last_mut().unwrap() {
1313                                 route_hop.node_features = features.to_context();
1314                         }
1315                 }
1316         }
1317
1318         let route = Route { paths: selected_paths.into_iter().map(|path| path.into_iter().collect()).collect::<Result<Vec<_>, _>>()? };
1319         log_info!(logger, "Got route to {}: {}", payee, log_route!(route));
1320         Ok(route)
1321 }
1322
1323 #[cfg(test)]
1324 mod tests {
1325         use routing::network_graph::{NetworkGraph, NetGraphMsgHandler};
1326         use routing::router::{get_route, Route, RouteHint, RouteHintHop, RouteHop, RoutingFees};
1327         use routing::scorer::Scorer;
1328         use chain::transaction::OutPoint;
1329         use ln::features::{ChannelFeatures, InitFeatures, InvoiceFeatures, NodeFeatures};
1330         use ln::msgs::{ErrorAction, LightningError, OptionalField, UnsignedChannelAnnouncement, ChannelAnnouncement, RoutingMessageHandler,
1331            NodeAnnouncement, UnsignedNodeAnnouncement, ChannelUpdate, UnsignedChannelUpdate};
1332         use ln::channelmanager;
1333         use util::test_utils;
1334         use util::ser::Writeable;
1335
1336         use bitcoin::hashes::sha256d::Hash as Sha256dHash;
1337         use bitcoin::hashes::Hash;
1338         use bitcoin::network::constants::Network;
1339         use bitcoin::blockdata::constants::genesis_block;
1340         use bitcoin::blockdata::script::Builder;
1341         use bitcoin::blockdata::opcodes;
1342         use bitcoin::blockdata::transaction::TxOut;
1343
1344         use hex;
1345
1346         use bitcoin::secp256k1::key::{PublicKey,SecretKey};
1347         use bitcoin::secp256k1::{Secp256k1, All};
1348
1349         use prelude::*;
1350         use sync::{self, Arc};
1351
1352         fn get_channel_details(short_channel_id: Option<u64>, node_id: PublicKey,
1353                         features: InitFeatures, outbound_capacity_msat: u64) -> channelmanager::ChannelDetails {
1354                 channelmanager::ChannelDetails {
1355                         channel_id: [0; 32],
1356                         counterparty: channelmanager::ChannelCounterparty {
1357                                 features,
1358                                 node_id,
1359                                 unspendable_punishment_reserve: 0,
1360                                 forwarding_info: None,
1361                         },
1362                         funding_txo: Some(OutPoint { txid: bitcoin::Txid::from_slice(&[0; 32]).unwrap(), index: 0 }),
1363                         short_channel_id,
1364                         channel_value_satoshis: 0,
1365                         user_channel_id: 0,
1366                         outbound_capacity_msat,
1367                         inbound_capacity_msat: 42,
1368                         unspendable_punishment_reserve: None,
1369                         confirmations_required: None,
1370                         force_close_spend_delay: None,
1371                         is_outbound: true, is_funding_locked: true,
1372                         is_usable: true, is_public: true,
1373                 }
1374         }
1375
1376         // Using the same keys for LN and BTC ids
1377         fn add_channel(
1378                 net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
1379                 secp_ctx: &Secp256k1<All>, node_1_privkey: &SecretKey, node_2_privkey: &SecretKey, features: ChannelFeatures, short_channel_id: u64
1380         ) {
1381                 let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
1382                 let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
1383
1384                 let unsigned_announcement = UnsignedChannelAnnouncement {
1385                         features,
1386                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1387                         short_channel_id,
1388                         node_id_1,
1389                         node_id_2,
1390                         bitcoin_key_1: node_id_1,
1391                         bitcoin_key_2: node_id_2,
1392                         excess_data: Vec::new(),
1393                 };
1394
1395                 let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
1396                 let valid_announcement = ChannelAnnouncement {
1397                         node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
1398                         node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
1399                         bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
1400                         bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
1401                         contents: unsigned_announcement.clone(),
1402                 };
1403                 match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
1404                         Ok(res) => assert!(res),
1405                         _ => panic!()
1406                 };
1407         }
1408
1409         fn update_channel(
1410                 net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
1411                 secp_ctx: &Secp256k1<All>, node_privkey: &SecretKey, update: UnsignedChannelUpdate
1412         ) {
1413                 let msghash = hash_to_message!(&Sha256dHash::hash(&update.encode()[..])[..]);
1414                 let valid_channel_update = ChannelUpdate {
1415                         signature: secp_ctx.sign(&msghash, node_privkey),
1416                         contents: update.clone()
1417                 };
1418
1419                 match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
1420                         Ok(res) => assert!(res),
1421                         Err(_) => panic!()
1422                 };
1423         }
1424
1425         fn add_or_update_node(
1426                 net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
1427                 secp_ctx: &Secp256k1<All>, node_privkey: &SecretKey, features: NodeFeatures, timestamp: u32
1428         ) {
1429                 let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
1430                 let unsigned_announcement = UnsignedNodeAnnouncement {
1431                         features,
1432                         timestamp,
1433                         node_id,
1434                         rgb: [0; 3],
1435                         alias: [0; 32],
1436                         addresses: Vec::new(),
1437                         excess_address_data: Vec::new(),
1438                         excess_data: Vec::new(),
1439                 };
1440                 let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
1441                 let valid_announcement = NodeAnnouncement {
1442                         signature: secp_ctx.sign(&msghash, node_privkey),
1443                         contents: unsigned_announcement.clone()
1444                 };
1445
1446                 match net_graph_msg_handler.handle_node_announcement(&valid_announcement) {
1447                         Ok(_) => (),
1448                         Err(_) => panic!()
1449                 };
1450         }
1451
1452         fn get_nodes(secp_ctx: &Secp256k1<All>) -> (SecretKey, PublicKey, Vec<SecretKey>, Vec<PublicKey>) {
1453                 let privkeys: Vec<SecretKey> = (2..10).map(|i| {
1454                         SecretKey::from_slice(&hex::decode(format!("{:02}", i).repeat(32)).unwrap()[..]).unwrap()
1455                 }).collect();
1456
1457                 let pubkeys = privkeys.iter().map(|secret| PublicKey::from_secret_key(&secp_ctx, secret)).collect();
1458
1459                 let our_privkey = SecretKey::from_slice(&hex::decode("01".repeat(32)).unwrap()[..]).unwrap();
1460                 let our_id = PublicKey::from_secret_key(&secp_ctx, &our_privkey);
1461
1462                 (our_privkey, our_id, privkeys, pubkeys)
1463         }
1464
1465         fn id_to_feature_flags(id: u8) -> Vec<u8> {
1466                 // Set the feature flags to the id'th odd (ie non-required) feature bit so that we can
1467                 // test for it later.
1468                 let idx = (id - 1) * 2 + 1;
1469                 if idx > 8*3 {
1470                         vec![1 << (idx - 8*3), 0, 0, 0]
1471                 } else if idx > 8*2 {
1472                         vec![1 << (idx - 8*2), 0, 0]
1473                 } else if idx > 8*1 {
1474                         vec![1 << (idx - 8*1), 0]
1475                 } else {
1476                         vec![1 << idx]
1477                 }
1478         }
1479
1480         fn build_graph() -> (Secp256k1<All>, NetGraphMsgHandler<sync::Arc<test_utils::TestChainSource>, sync::Arc<crate::util::test_utils::TestLogger>>, sync::Arc<test_utils::TestChainSource>, sync::Arc<test_utils::TestLogger>) {
1481                 let secp_ctx = Secp256k1::new();
1482                 let logger = Arc::new(test_utils::TestLogger::new());
1483                 let chain_monitor = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
1484                 let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
1485                 let net_graph_msg_handler = NetGraphMsgHandler::new(network_graph, None, Arc::clone(&logger));
1486                 // Build network from our_id to node6:
1487                 //
1488                 //        -1(1)2-  node0  -1(3)2-
1489                 //       /                       \
1490                 // our_id -1(12)2- node7 -1(13)2--- node2
1491                 //       \                       /
1492                 //        -1(2)2-  node1  -1(4)2-
1493                 //
1494                 //
1495                 // chan1  1-to-2: disabled
1496                 // chan1  2-to-1: enabled, 0 fee
1497                 //
1498                 // chan2  1-to-2: enabled, ignored fee
1499                 // chan2  2-to-1: enabled, 0 fee
1500                 //
1501                 // chan3  1-to-2: enabled, 0 fee
1502                 // chan3  2-to-1: enabled, 100 msat fee
1503                 //
1504                 // chan4  1-to-2: enabled, 100% fee
1505                 // chan4  2-to-1: enabled, 0 fee
1506                 //
1507                 // chan12 1-to-2: enabled, ignored fee
1508                 // chan12 2-to-1: enabled, 0 fee
1509                 //
1510                 // chan13 1-to-2: enabled, 200% fee
1511                 // chan13 2-to-1: enabled, 0 fee
1512                 //
1513                 //
1514                 //       -1(5)2- node3 -1(8)2--
1515                 //       |         2          |
1516                 //       |       (11)         |
1517                 //      /          1           \
1518                 // node2--1(6)2- node4 -1(9)2--- node6 (not in global route map)
1519                 //      \                      /
1520                 //       -1(7)2- node5 -1(10)2-
1521                 //
1522                 // Channels 5, 8, 9 and 10 are private channels.
1523                 //
1524                 // chan5  1-to-2: enabled, 100 msat fee
1525                 // chan5  2-to-1: enabled, 0 fee
1526                 //
1527                 // chan6  1-to-2: enabled, 0 fee
1528                 // chan6  2-to-1: enabled, 0 fee
1529                 //
1530                 // chan7  1-to-2: enabled, 100% fee
1531                 // chan7  2-to-1: enabled, 0 fee
1532                 //
1533                 // chan8  1-to-2: enabled, variable fee (0 then 1000 msat)
1534                 // chan8  2-to-1: enabled, 0 fee
1535                 //
1536                 // chan9  1-to-2: enabled, 1001 msat fee
1537                 // chan9  2-to-1: enabled, 0 fee
1538                 //
1539                 // chan10 1-to-2: enabled, 0 fee
1540                 // chan10 2-to-1: enabled, 0 fee
1541                 //
1542                 // chan11 1-to-2: enabled, 0 fee
1543                 // chan11 2-to-1: enabled, 0 fee
1544
1545                 let (our_privkey, _, privkeys, _) = get_nodes(&secp_ctx);
1546
1547                 add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[0], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
1548                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
1549                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1550                         short_channel_id: 1,
1551                         timestamp: 1,
1552                         flags: 1,
1553                         cltv_expiry_delta: 0,
1554                         htlc_minimum_msat: 0,
1555                         htlc_maximum_msat: OptionalField::Absent,
1556                         fee_base_msat: 0,
1557                         fee_proportional_millionths: 0,
1558                         excess_data: Vec::new()
1559                 });
1560
1561                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
1562
1563                 add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
1564                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1565                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1566                         short_channel_id: 2,
1567                         timestamp: 1,
1568                         flags: 0,
1569                         cltv_expiry_delta: u16::max_value(),
1570                         htlc_minimum_msat: 0,
1571                         htlc_maximum_msat: OptionalField::Absent,
1572                         fee_base_msat: u32::max_value(),
1573                         fee_proportional_millionths: u32::max_value(),
1574                         excess_data: Vec::new()
1575                 });
1576                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
1577                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1578                         short_channel_id: 2,
1579                         timestamp: 1,
1580                         flags: 1,
1581                         cltv_expiry_delta: 0,
1582                         htlc_minimum_msat: 0,
1583                         htlc_maximum_msat: OptionalField::Absent,
1584                         fee_base_msat: 0,
1585                         fee_proportional_millionths: 0,
1586                         excess_data: Vec::new()
1587                 });
1588
1589                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
1590
1591                 add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[7], ChannelFeatures::from_le_bytes(id_to_feature_flags(12)), 12);
1592                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1593                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1594                         short_channel_id: 12,
1595                         timestamp: 1,
1596                         flags: 0,
1597                         cltv_expiry_delta: u16::max_value(),
1598                         htlc_minimum_msat: 0,
1599                         htlc_maximum_msat: OptionalField::Absent,
1600                         fee_base_msat: u32::max_value(),
1601                         fee_proportional_millionths: u32::max_value(),
1602                         excess_data: Vec::new()
1603                 });
1604                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
1605                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1606                         short_channel_id: 12,
1607                         timestamp: 1,
1608                         flags: 1,
1609                         cltv_expiry_delta: 0,
1610                         htlc_minimum_msat: 0,
1611                         htlc_maximum_msat: OptionalField::Absent,
1612                         fee_base_msat: 0,
1613                         fee_proportional_millionths: 0,
1614                         excess_data: Vec::new()
1615                 });
1616
1617                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], NodeFeatures::from_le_bytes(id_to_feature_flags(8)), 0);
1618
1619                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
1620                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
1621                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1622                         short_channel_id: 3,
1623                         timestamp: 1,
1624                         flags: 0,
1625                         cltv_expiry_delta: (3 << 8) | 1,
1626                         htlc_minimum_msat: 0,
1627                         htlc_maximum_msat: OptionalField::Absent,
1628                         fee_base_msat: 0,
1629                         fee_proportional_millionths: 0,
1630                         excess_data: Vec::new()
1631                 });
1632                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1633                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1634                         short_channel_id: 3,
1635                         timestamp: 1,
1636                         flags: 1,
1637                         cltv_expiry_delta: (3 << 8) | 2,
1638                         htlc_minimum_msat: 0,
1639                         htlc_maximum_msat: OptionalField::Absent,
1640                         fee_base_msat: 100,
1641                         fee_proportional_millionths: 0,
1642                         excess_data: Vec::new()
1643                 });
1644
1645                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
1646                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
1647                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1648                         short_channel_id: 4,
1649                         timestamp: 1,
1650                         flags: 0,
1651                         cltv_expiry_delta: (4 << 8) | 1,
1652                         htlc_minimum_msat: 0,
1653                         htlc_maximum_msat: OptionalField::Absent,
1654                         fee_base_msat: 0,
1655                         fee_proportional_millionths: 1000000,
1656                         excess_data: Vec::new()
1657                 });
1658                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1659                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1660                         short_channel_id: 4,
1661                         timestamp: 1,
1662                         flags: 1,
1663                         cltv_expiry_delta: (4 << 8) | 2,
1664                         htlc_minimum_msat: 0,
1665                         htlc_maximum_msat: OptionalField::Absent,
1666                         fee_base_msat: 0,
1667                         fee_proportional_millionths: 0,
1668                         excess_data: Vec::new()
1669                 });
1670
1671                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(13)), 13);
1672                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
1673                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1674                         short_channel_id: 13,
1675                         timestamp: 1,
1676                         flags: 0,
1677                         cltv_expiry_delta: (13 << 8) | 1,
1678                         htlc_minimum_msat: 0,
1679                         htlc_maximum_msat: OptionalField::Absent,
1680                         fee_base_msat: 0,
1681                         fee_proportional_millionths: 2000000,
1682                         excess_data: Vec::new()
1683                 });
1684                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1685                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1686                         short_channel_id: 13,
1687                         timestamp: 1,
1688                         flags: 1,
1689                         cltv_expiry_delta: (13 << 8) | 2,
1690                         htlc_minimum_msat: 0,
1691                         htlc_maximum_msat: OptionalField::Absent,
1692                         fee_base_msat: 0,
1693                         fee_proportional_millionths: 0,
1694                         excess_data: Vec::new()
1695                 });
1696
1697                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
1698
1699                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
1700                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1701                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1702                         short_channel_id: 6,
1703                         timestamp: 1,
1704                         flags: 0,
1705                         cltv_expiry_delta: (6 << 8) | 1,
1706                         htlc_minimum_msat: 0,
1707                         htlc_maximum_msat: OptionalField::Absent,
1708                         fee_base_msat: 0,
1709                         fee_proportional_millionths: 0,
1710                         excess_data: Vec::new()
1711                 });
1712                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
1713                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1714                         short_channel_id: 6,
1715                         timestamp: 1,
1716                         flags: 1,
1717                         cltv_expiry_delta: (6 << 8) | 2,
1718                         htlc_minimum_msat: 0,
1719                         htlc_maximum_msat: OptionalField::Absent,
1720                         fee_base_msat: 0,
1721                         fee_proportional_millionths: 0,
1722                         excess_data: Vec::new(),
1723                 });
1724
1725                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(11)), 11);
1726                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
1727                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1728                         short_channel_id: 11,
1729                         timestamp: 1,
1730                         flags: 0,
1731                         cltv_expiry_delta: (11 << 8) | 1,
1732                         htlc_minimum_msat: 0,
1733                         htlc_maximum_msat: OptionalField::Absent,
1734                         fee_base_msat: 0,
1735                         fee_proportional_millionths: 0,
1736                         excess_data: Vec::new()
1737                 });
1738                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
1739                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1740                         short_channel_id: 11,
1741                         timestamp: 1,
1742                         flags: 1,
1743                         cltv_expiry_delta: (11 << 8) | 2,
1744                         htlc_minimum_msat: 0,
1745                         htlc_maximum_msat: OptionalField::Absent,
1746                         fee_base_msat: 0,
1747                         fee_proportional_millionths: 0,
1748                         excess_data: Vec::new()
1749                 });
1750
1751                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(5)), 0);
1752
1753                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
1754
1755                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[5], ChannelFeatures::from_le_bytes(id_to_feature_flags(7)), 7);
1756                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1757                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1758                         short_channel_id: 7,
1759                         timestamp: 1,
1760                         flags: 0,
1761                         cltv_expiry_delta: (7 << 8) | 1,
1762                         htlc_minimum_msat: 0,
1763                         htlc_maximum_msat: OptionalField::Absent,
1764                         fee_base_msat: 0,
1765                         fee_proportional_millionths: 1000000,
1766                         excess_data: Vec::new()
1767                 });
1768                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[5], UnsignedChannelUpdate {
1769                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1770                         short_channel_id: 7,
1771                         timestamp: 1,
1772                         flags: 1,
1773                         cltv_expiry_delta: (7 << 8) | 2,
1774                         htlc_minimum_msat: 0,
1775                         htlc_maximum_msat: OptionalField::Absent,
1776                         fee_base_msat: 0,
1777                         fee_proportional_millionths: 0,
1778                         excess_data: Vec::new()
1779                 });
1780
1781                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[5], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
1782
1783                 (secp_ctx, net_graph_msg_handler, chain_monitor, logger)
1784         }
1785
1786         #[test]
1787         fn simple_route_test() {
1788                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
1789                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
1790                 let scorer = Scorer::new(0);
1791
1792                 // Simple route to 2 via 1
1793
1794                 if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 0, 42, Arc::clone(&logger), &scorer) {
1795                         assert_eq!(err, "Cannot send a payment of 0 msat");
1796                 } else { panic!(); }
1797
1798                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
1799                 assert_eq!(route.paths[0].len(), 2);
1800
1801                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
1802                 assert_eq!(route.paths[0][0].short_channel_id, 2);
1803                 assert_eq!(route.paths[0][0].fee_msat, 100);
1804                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
1805                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
1806                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
1807
1808                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
1809                 assert_eq!(route.paths[0][1].short_channel_id, 4);
1810                 assert_eq!(route.paths[0][1].fee_msat, 100);
1811                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
1812                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
1813                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
1814         }
1815
1816         #[test]
1817         fn invalid_first_hop_test() {
1818                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
1819                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
1820                 let scorer = Scorer::new(0);
1821
1822                 // Simple route to 2 via 1
1823
1824                 let our_chans = vec![get_channel_details(Some(2), our_id, InitFeatures::from_le_bytes(vec![0b11]), 100000)];
1825
1826                 if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger), &scorer) {
1827                         assert_eq!(err, "First hop cannot have our_node_pubkey as a destination.");
1828                 } else { panic!(); }
1829
1830                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
1831                 assert_eq!(route.paths[0].len(), 2);
1832         }
1833
1834         #[test]
1835         fn htlc_minimum_test() {
1836                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
1837                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
1838                 let scorer = Scorer::new(0);
1839
1840                 // Simple route to 2 via 1
1841
1842                 // Disable other paths
1843                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1844                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1845                         short_channel_id: 12,
1846                         timestamp: 2,
1847                         flags: 2, // to disable
1848                         cltv_expiry_delta: 0,
1849                         htlc_minimum_msat: 0,
1850                         htlc_maximum_msat: OptionalField::Absent,
1851                         fee_base_msat: 0,
1852                         fee_proportional_millionths: 0,
1853                         excess_data: Vec::new()
1854                 });
1855                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
1856                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1857                         short_channel_id: 3,
1858                         timestamp: 2,
1859                         flags: 2, // to disable
1860                         cltv_expiry_delta: 0,
1861                         htlc_minimum_msat: 0,
1862                         htlc_maximum_msat: OptionalField::Absent,
1863                         fee_base_msat: 0,
1864                         fee_proportional_millionths: 0,
1865                         excess_data: Vec::new()
1866                 });
1867                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
1868                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1869                         short_channel_id: 13,
1870                         timestamp: 2,
1871                         flags: 2, // to disable
1872                         cltv_expiry_delta: 0,
1873                         htlc_minimum_msat: 0,
1874                         htlc_maximum_msat: OptionalField::Absent,
1875                         fee_base_msat: 0,
1876                         fee_proportional_millionths: 0,
1877                         excess_data: Vec::new()
1878                 });
1879                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1880                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1881                         short_channel_id: 6,
1882                         timestamp: 2,
1883                         flags: 2, // to disable
1884                         cltv_expiry_delta: 0,
1885                         htlc_minimum_msat: 0,
1886                         htlc_maximum_msat: OptionalField::Absent,
1887                         fee_base_msat: 0,
1888                         fee_proportional_millionths: 0,
1889                         excess_data: Vec::new()
1890                 });
1891                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
1892                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1893                         short_channel_id: 7,
1894                         timestamp: 2,
1895                         flags: 2, // to disable
1896                         cltv_expiry_delta: 0,
1897                         htlc_minimum_msat: 0,
1898                         htlc_maximum_msat: OptionalField::Absent,
1899                         fee_base_msat: 0,
1900                         fee_proportional_millionths: 0,
1901                         excess_data: Vec::new()
1902                 });
1903
1904                 // Check against amount_to_transfer_over_msat.
1905                 // Set minimal HTLC of 200_000_000 msat.
1906                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1907                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1908                         short_channel_id: 2,
1909                         timestamp: 3,
1910                         flags: 0,
1911                         cltv_expiry_delta: 0,
1912                         htlc_minimum_msat: 200_000_000,
1913                         htlc_maximum_msat: OptionalField::Absent,
1914                         fee_base_msat: 0,
1915                         fee_proportional_millionths: 0,
1916                         excess_data: Vec::new()
1917                 });
1918
1919                 // Second hop only allows to forward 199_999_999 at most, thus not allowing the first hop to
1920                 // be used.
1921                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
1922                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1923                         short_channel_id: 4,
1924                         timestamp: 3,
1925                         flags: 0,
1926                         cltv_expiry_delta: 0,
1927                         htlc_minimum_msat: 0,
1928                         htlc_maximum_msat: OptionalField::Present(199_999_999),
1929                         fee_base_msat: 0,
1930                         fee_proportional_millionths: 0,
1931                         excess_data: Vec::new()
1932                 });
1933
1934                 // Not possible to send 199_999_999, because the minimum on channel=2 is 200_000_000.
1935                 if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 199_999_999, 42, Arc::clone(&logger), &scorer) {
1936                         assert_eq!(err, "Failed to find a path to the given destination");
1937                 } else { panic!(); }
1938
1939                 // Lift the restriction on the first hop.
1940                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1941                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1942                         short_channel_id: 2,
1943                         timestamp: 4,
1944                         flags: 0,
1945                         cltv_expiry_delta: 0,
1946                         htlc_minimum_msat: 0,
1947                         htlc_maximum_msat: OptionalField::Absent,
1948                         fee_base_msat: 0,
1949                         fee_proportional_millionths: 0,
1950                         excess_data: Vec::new()
1951                 });
1952
1953                 // A payment above the minimum should pass
1954                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 199_999_999, 42, Arc::clone(&logger), &scorer).unwrap();
1955                 assert_eq!(route.paths[0].len(), 2);
1956         }
1957
1958         #[test]
1959         fn htlc_minimum_overpay_test() {
1960                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
1961                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
1962                 let scorer = Scorer::new(0);
1963
1964                 // A route to node#2 via two paths.
1965                 // One path allows transferring 35-40 sats, another one also allows 35-40 sats.
1966                 // Thus, they can't send 60 without overpaying.
1967                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1968                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1969                         short_channel_id: 2,
1970                         timestamp: 2,
1971                         flags: 0,
1972                         cltv_expiry_delta: 0,
1973                         htlc_minimum_msat: 35_000,
1974                         htlc_maximum_msat: OptionalField::Present(40_000),
1975                         fee_base_msat: 0,
1976                         fee_proportional_millionths: 0,
1977                         excess_data: Vec::new()
1978                 });
1979                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
1980                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1981                         short_channel_id: 12,
1982                         timestamp: 3,
1983                         flags: 0,
1984                         cltv_expiry_delta: 0,
1985                         htlc_minimum_msat: 35_000,
1986                         htlc_maximum_msat: OptionalField::Present(40_000),
1987                         fee_base_msat: 0,
1988                         fee_proportional_millionths: 0,
1989                         excess_data: Vec::new()
1990                 });
1991
1992                 // Make 0 fee.
1993                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
1994                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
1995                         short_channel_id: 13,
1996                         timestamp: 2,
1997                         flags: 0,
1998                         cltv_expiry_delta: 0,
1999                         htlc_minimum_msat: 0,
2000                         htlc_maximum_msat: OptionalField::Absent,
2001                         fee_base_msat: 0,
2002                         fee_proportional_millionths: 0,
2003                         excess_data: Vec::new()
2004                 });
2005                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
2006                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2007                         short_channel_id: 4,
2008                         timestamp: 2,
2009                         flags: 0,
2010                         cltv_expiry_delta: 0,
2011                         htlc_minimum_msat: 0,
2012                         htlc_maximum_msat: OptionalField::Absent,
2013                         fee_base_msat: 0,
2014                         fee_proportional_millionths: 0,
2015                         excess_data: Vec::new()
2016                 });
2017
2018                 // Disable other paths
2019                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2020                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2021                         short_channel_id: 1,
2022                         timestamp: 3,
2023                         flags: 2, // to disable
2024                         cltv_expiry_delta: 0,
2025                         htlc_minimum_msat: 0,
2026                         htlc_maximum_msat: OptionalField::Absent,
2027                         fee_base_msat: 0,
2028                         fee_proportional_millionths: 0,
2029                         excess_data: Vec::new()
2030                 });
2031
2032                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2033                         Some(InvoiceFeatures::known()), None, &Vec::new(), 60_000, 42, Arc::clone(&logger), &scorer).unwrap();
2034                 // Overpay fees to hit htlc_minimum_msat.
2035                 let overpaid_fees = route.paths[0][0].fee_msat + route.paths[1][0].fee_msat;
2036                 // TODO: this could be better balanced to overpay 10k and not 15k.
2037                 assert_eq!(overpaid_fees, 15_000);
2038
2039                 // Now, test that if there are 2 paths, a "cheaper" by fee path wouldn't be prioritized
2040                 // while taking even more fee to match htlc_minimum_msat.
2041                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2042                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2043                         short_channel_id: 12,
2044                         timestamp: 4,
2045                         flags: 0,
2046                         cltv_expiry_delta: 0,
2047                         htlc_minimum_msat: 65_000,
2048                         htlc_maximum_msat: OptionalField::Present(80_000),
2049                         fee_base_msat: 0,
2050                         fee_proportional_millionths: 0,
2051                         excess_data: Vec::new()
2052                 });
2053                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2054                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2055                         short_channel_id: 2,
2056                         timestamp: 3,
2057                         flags: 0,
2058                         cltv_expiry_delta: 0,
2059                         htlc_minimum_msat: 0,
2060                         htlc_maximum_msat: OptionalField::Absent,
2061                         fee_base_msat: 0,
2062                         fee_proportional_millionths: 0,
2063                         excess_data: Vec::new()
2064                 });
2065                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
2066                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2067                         short_channel_id: 4,
2068                         timestamp: 4,
2069                         flags: 0,
2070                         cltv_expiry_delta: 0,
2071                         htlc_minimum_msat: 0,
2072                         htlc_maximum_msat: OptionalField::Absent,
2073                         fee_base_msat: 0,
2074                         fee_proportional_millionths: 100_000,
2075                         excess_data: Vec::new()
2076                 });
2077
2078                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2079                         Some(InvoiceFeatures::known()), None, &Vec::new(), 60_000, 42, Arc::clone(&logger), &scorer).unwrap();
2080                 // Fine to overpay for htlc_minimum_msat if it allows us to save fee.
2081                 assert_eq!(route.paths.len(), 1);
2082                 assert_eq!(route.paths[0][0].short_channel_id, 12);
2083                 let fees = route.paths[0][0].fee_msat;
2084                 assert_eq!(fees, 5_000);
2085
2086                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2087                         Some(InvoiceFeatures::known()), None, &Vec::new(), 50_000, 42, Arc::clone(&logger), &scorer).unwrap();
2088                 // Not fine to overpay for htlc_minimum_msat if it requires paying more than fee on
2089                 // the other channel.
2090                 assert_eq!(route.paths.len(), 1);
2091                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2092                 let fees = route.paths[0][0].fee_msat;
2093                 assert_eq!(fees, 5_000);
2094         }
2095
2096         #[test]
2097         fn disable_channels_test() {
2098                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2099                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
2100                 let scorer = Scorer::new(0);
2101
2102                 // // Disable channels 4 and 12 by flags=2
2103                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
2104                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2105                         short_channel_id: 4,
2106                         timestamp: 2,
2107                         flags: 2, // to disable
2108                         cltv_expiry_delta: 0,
2109                         htlc_minimum_msat: 0,
2110                         htlc_maximum_msat: OptionalField::Absent,
2111                         fee_base_msat: 0,
2112                         fee_proportional_millionths: 0,
2113                         excess_data: Vec::new()
2114                 });
2115                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2116                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2117                         short_channel_id: 12,
2118                         timestamp: 2,
2119                         flags: 2, // to disable
2120                         cltv_expiry_delta: 0,
2121                         htlc_minimum_msat: 0,
2122                         htlc_maximum_msat: OptionalField::Absent,
2123                         fee_base_msat: 0,
2124                         fee_proportional_millionths: 0,
2125                         excess_data: Vec::new()
2126                 });
2127
2128                 // If all the channels require some features we don't understand, route should fail
2129                 if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 100, 42, Arc::clone(&logger), &scorer) {
2130                         assert_eq!(err, "Failed to find a path to the given destination");
2131                 } else { panic!(); }
2132
2133                 // If we specify a channel to node7, that overrides our local channel view and that gets used
2134                 let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
2135                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()),  &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2136                 assert_eq!(route.paths[0].len(), 2);
2137
2138                 assert_eq!(route.paths[0][0].pubkey, nodes[7]);
2139                 assert_eq!(route.paths[0][0].short_channel_id, 42);
2140                 assert_eq!(route.paths[0][0].fee_msat, 200);
2141                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
2142                 assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]); // it should also override our view of their features
2143                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::<u8>::new()); // No feature flags will meet the relevant-to-channel conversion
2144
2145                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2146                 assert_eq!(route.paths[0][1].short_channel_id, 13);
2147                 assert_eq!(route.paths[0][1].fee_msat, 100);
2148                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
2149                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2150                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
2151         }
2152
2153         #[test]
2154         fn disable_node_test() {
2155                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2156                 let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
2157                 let scorer = Scorer::new(0);
2158
2159                 // Disable nodes 1, 2, and 8 by requiring unknown feature bits
2160                 let unknown_features = NodeFeatures::known().set_unknown_feature_required();
2161                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[0], unknown_features.clone(), 1);
2162                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], unknown_features.clone(), 1);
2163                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[7], unknown_features.clone(), 1);
2164
2165                 // If all nodes require some features we don't understand, route should fail
2166                 if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 100, 42, Arc::clone(&logger), &scorer) {
2167                         assert_eq!(err, "Failed to find a path to the given destination");
2168                 } else { panic!(); }
2169
2170                 // If we specify a channel to node7, that overrides our local channel view and that gets used
2171                 let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
2172                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2173                 assert_eq!(route.paths[0].len(), 2);
2174
2175                 assert_eq!(route.paths[0][0].pubkey, nodes[7]);
2176                 assert_eq!(route.paths[0][0].short_channel_id, 42);
2177                 assert_eq!(route.paths[0][0].fee_msat, 200);
2178                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
2179                 assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]); // it should also override our view of their features
2180                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::<u8>::new()); // No feature flags will meet the relevant-to-channel conversion
2181
2182                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2183                 assert_eq!(route.paths[0][1].short_channel_id, 13);
2184                 assert_eq!(route.paths[0][1].fee_msat, 100);
2185                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
2186                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2187                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
2188
2189                 // Note that we don't test disabling node 3 and failing to route to it, as we (somewhat
2190                 // naively) assume that the user checked the feature bits on the invoice, which override
2191                 // the node_announcement.
2192         }
2193
2194         #[test]
2195         fn our_chans_test() {
2196                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2197                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
2198                 let scorer = Scorer::new(0);
2199
2200                 // Route to 1 via 2 and 3 because our channel to 1 is disabled
2201                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[0], None, None, &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2202                 assert_eq!(route.paths[0].len(), 3);
2203
2204                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2205                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2206                 assert_eq!(route.paths[0][0].fee_msat, 200);
2207                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2208                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2209                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2210
2211                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2212                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2213                 assert_eq!(route.paths[0][1].fee_msat, 100);
2214                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (3 << 8) | 2);
2215                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2216                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2217
2218                 assert_eq!(route.paths[0][2].pubkey, nodes[0]);
2219                 assert_eq!(route.paths[0][2].short_channel_id, 3);
2220                 assert_eq!(route.paths[0][2].fee_msat, 100);
2221                 assert_eq!(route.paths[0][2].cltv_expiry_delta, 42);
2222                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(1));
2223                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(3));
2224
2225                 // If we specify a channel to node7, that overrides our local channel view and that gets used
2226                 let our_chans = vec![get_channel_details(Some(42), nodes[7].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
2227                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2228                 assert_eq!(route.paths[0].len(), 2);
2229
2230                 assert_eq!(route.paths[0][0].pubkey, nodes[7]);
2231                 assert_eq!(route.paths[0][0].short_channel_id, 42);
2232                 assert_eq!(route.paths[0][0].fee_msat, 200);
2233                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
2234                 assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]);
2235                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::<u8>::new()); // No feature flags will meet the relevant-to-channel conversion
2236
2237                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2238                 assert_eq!(route.paths[0][1].short_channel_id, 13);
2239                 assert_eq!(route.paths[0][1].fee_msat, 100);
2240                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
2241                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2242                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
2243         }
2244
2245         fn last_hops(nodes: &Vec<PublicKey>) -> Vec<RouteHint> {
2246                 let zero_fees = RoutingFees {
2247                         base_msat: 0,
2248                         proportional_millionths: 0,
2249                 };
2250                 vec![RouteHint(vec![RouteHintHop {
2251                         src_node_id: nodes[3],
2252                         short_channel_id: 8,
2253                         fees: zero_fees,
2254                         cltv_expiry_delta: (8 << 8) | 1,
2255                         htlc_minimum_msat: None,
2256                         htlc_maximum_msat: None,
2257                 }
2258                 ]), RouteHint(vec![RouteHintHop {
2259                         src_node_id: nodes[4],
2260                         short_channel_id: 9,
2261                         fees: RoutingFees {
2262                                 base_msat: 1001,
2263                                 proportional_millionths: 0,
2264                         },
2265                         cltv_expiry_delta: (9 << 8) | 1,
2266                         htlc_minimum_msat: None,
2267                         htlc_maximum_msat: None,
2268                 }]), RouteHint(vec![RouteHintHop {
2269                         src_node_id: nodes[5],
2270                         short_channel_id: 10,
2271                         fees: zero_fees,
2272                         cltv_expiry_delta: (10 << 8) | 1,
2273                         htlc_minimum_msat: None,
2274                         htlc_maximum_msat: None,
2275                 }])]
2276         }
2277
2278         fn last_hops_multi_private_channels(nodes: &Vec<PublicKey>) -> Vec<RouteHint> {
2279                 let zero_fees = RoutingFees {
2280                         base_msat: 0,
2281                         proportional_millionths: 0,
2282                 };
2283                 vec![RouteHint(vec![RouteHintHop {
2284                         src_node_id: nodes[2],
2285                         short_channel_id: 5,
2286                         fees: RoutingFees {
2287                                 base_msat: 100,
2288                                 proportional_millionths: 0,
2289                         },
2290                         cltv_expiry_delta: (5 << 8) | 1,
2291                         htlc_minimum_msat: None,
2292                         htlc_maximum_msat: None,
2293                 }, RouteHintHop {
2294                         src_node_id: nodes[3],
2295                         short_channel_id: 8,
2296                         fees: zero_fees,
2297                         cltv_expiry_delta: (8 << 8) | 1,
2298                         htlc_minimum_msat: None,
2299                         htlc_maximum_msat: None,
2300                 }
2301                 ]), RouteHint(vec![RouteHintHop {
2302                         src_node_id: nodes[4],
2303                         short_channel_id: 9,
2304                         fees: RoutingFees {
2305                                 base_msat: 1001,
2306                                 proportional_millionths: 0,
2307                         },
2308                         cltv_expiry_delta: (9 << 8) | 1,
2309                         htlc_minimum_msat: None,
2310                         htlc_maximum_msat: None,
2311                 }]), RouteHint(vec![RouteHintHop {
2312                         src_node_id: nodes[5],
2313                         short_channel_id: 10,
2314                         fees: zero_fees,
2315                         cltv_expiry_delta: (10 << 8) | 1,
2316                         htlc_minimum_msat: None,
2317                         htlc_maximum_msat: None,
2318                 }])]
2319         }
2320
2321         #[test]
2322         fn partial_route_hint_test() {
2323                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2324                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
2325                 let scorer = Scorer::new(0);
2326
2327                 // Simple test across 2, 3, 5, and 4 via a last_hop channel
2328                 // Tests the behaviour when the RouteHint contains a suboptimal hop.
2329                 // RouteHint may be partially used by the algo to build the best path.
2330
2331                 // First check that last hop can't have its source as the payee.
2332                 let invalid_last_hop = RouteHint(vec![RouteHintHop {
2333                         src_node_id: nodes[6],
2334                         short_channel_id: 8,
2335                         fees: RoutingFees {
2336                                 base_msat: 1000,
2337                                 proportional_millionths: 0,
2338                         },
2339                         cltv_expiry_delta: (8 << 8) | 1,
2340                         htlc_minimum_msat: None,
2341                         htlc_maximum_msat: None,
2342                 }]);
2343
2344                 let mut invalid_last_hops = last_hops_multi_private_channels(&nodes);
2345                 invalid_last_hops.push(invalid_last_hop);
2346                 {
2347                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &invalid_last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer) {
2348                                 assert_eq!(err, "Last hop cannot have a payee as a source.");
2349                         } else { panic!(); }
2350                 }
2351
2352                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &last_hops_multi_private_channels(&nodes).iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2353                 assert_eq!(route.paths[0].len(), 5);
2354
2355                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2356                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2357                 assert_eq!(route.paths[0][0].fee_msat, 100);
2358                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2359                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2360                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2361
2362                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2363                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2364                 assert_eq!(route.paths[0][1].fee_msat, 0);
2365                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (6 << 8) | 1);
2366                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2367                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2368
2369                 assert_eq!(route.paths[0][2].pubkey, nodes[4]);
2370                 assert_eq!(route.paths[0][2].short_channel_id, 6);
2371                 assert_eq!(route.paths[0][2].fee_msat, 0);
2372                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (11 << 8) | 1);
2373                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(5));
2374                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(6));
2375
2376                 assert_eq!(route.paths[0][3].pubkey, nodes[3]);
2377                 assert_eq!(route.paths[0][3].short_channel_id, 11);
2378                 assert_eq!(route.paths[0][3].fee_msat, 0);
2379                 assert_eq!(route.paths[0][3].cltv_expiry_delta, (8 << 8) | 1);
2380                 // If we have a peer in the node map, we'll use their features here since we don't have
2381                 // a way of figuring out their features from the invoice:
2382                 assert_eq!(route.paths[0][3].node_features.le_flags(), &id_to_feature_flags(4));
2383                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &id_to_feature_flags(11));
2384
2385                 assert_eq!(route.paths[0][4].pubkey, nodes[6]);
2386                 assert_eq!(route.paths[0][4].short_channel_id, 8);
2387                 assert_eq!(route.paths[0][4].fee_msat, 100);
2388                 assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
2389                 assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2390                 assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2391         }
2392
2393         fn empty_last_hop(nodes: &Vec<PublicKey>) -> Vec<RouteHint> {
2394                 let zero_fees = RoutingFees {
2395                         base_msat: 0,
2396                         proportional_millionths: 0,
2397                 };
2398                 vec![RouteHint(vec![RouteHintHop {
2399                         src_node_id: nodes[3],
2400                         short_channel_id: 8,
2401                         fees: zero_fees,
2402                         cltv_expiry_delta: (8 << 8) | 1,
2403                         htlc_minimum_msat: None,
2404                         htlc_maximum_msat: None,
2405                 }]), RouteHint(vec![
2406
2407                 ]), RouteHint(vec![RouteHintHop {
2408                         src_node_id: nodes[5],
2409                         short_channel_id: 10,
2410                         fees: zero_fees,
2411                         cltv_expiry_delta: (10 << 8) | 1,
2412                         htlc_minimum_msat: None,
2413                         htlc_maximum_msat: None,
2414                 }])]
2415         }
2416
2417         #[test]
2418         fn ignores_empty_last_hops_test() {
2419                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2420                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
2421                 let scorer = Scorer::new(0);
2422
2423                 // Test handling of an empty RouteHint passed in Invoice.
2424
2425                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &empty_last_hop(&nodes).iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2426                 assert_eq!(route.paths[0].len(), 5);
2427
2428                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2429                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2430                 assert_eq!(route.paths[0][0].fee_msat, 100);
2431                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2432                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2433                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2434
2435                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2436                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2437                 assert_eq!(route.paths[0][1].fee_msat, 0);
2438                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (6 << 8) | 1);
2439                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2440                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2441
2442                 assert_eq!(route.paths[0][2].pubkey, nodes[4]);
2443                 assert_eq!(route.paths[0][2].short_channel_id, 6);
2444                 assert_eq!(route.paths[0][2].fee_msat, 0);
2445                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (11 << 8) | 1);
2446                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(5));
2447                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(6));
2448
2449                 assert_eq!(route.paths[0][3].pubkey, nodes[3]);
2450                 assert_eq!(route.paths[0][3].short_channel_id, 11);
2451                 assert_eq!(route.paths[0][3].fee_msat, 0);
2452                 assert_eq!(route.paths[0][3].cltv_expiry_delta, (8 << 8) | 1);
2453                 // If we have a peer in the node map, we'll use their features here since we don't have
2454                 // a way of figuring out their features from the invoice:
2455                 assert_eq!(route.paths[0][3].node_features.le_flags(), &id_to_feature_flags(4));
2456                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &id_to_feature_flags(11));
2457
2458                 assert_eq!(route.paths[0][4].pubkey, nodes[6]);
2459                 assert_eq!(route.paths[0][4].short_channel_id, 8);
2460                 assert_eq!(route.paths[0][4].fee_msat, 100);
2461                 assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
2462                 assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2463                 assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2464         }
2465
2466         fn multi_hint_last_hops(nodes: &Vec<PublicKey>) -> Vec<RouteHint> {
2467                 let zero_fees = RoutingFees {
2468                         base_msat: 0,
2469                         proportional_millionths: 0,
2470                 };
2471                 vec![RouteHint(vec![RouteHintHop {
2472                         src_node_id: nodes[2],
2473                         short_channel_id: 5,
2474                         fees: RoutingFees {
2475                                 base_msat: 100,
2476                                 proportional_millionths: 0,
2477                         },
2478                         cltv_expiry_delta: (5 << 8) | 1,
2479                         htlc_minimum_msat: None,
2480                         htlc_maximum_msat: None,
2481                 }, RouteHintHop {
2482                         src_node_id: nodes[3],
2483                         short_channel_id: 8,
2484                         fees: zero_fees,
2485                         cltv_expiry_delta: (8 << 8) | 1,
2486                         htlc_minimum_msat: None,
2487                         htlc_maximum_msat: None,
2488                 }]), RouteHint(vec![RouteHintHop {
2489                         src_node_id: nodes[5],
2490                         short_channel_id: 10,
2491                         fees: zero_fees,
2492                         cltv_expiry_delta: (10 << 8) | 1,
2493                         htlc_minimum_msat: None,
2494                         htlc_maximum_msat: None,
2495                 }])]
2496         }
2497
2498         #[test]
2499         fn multi_hint_last_hops_test() {
2500                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2501                 let (_, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
2502                 let scorer = Scorer::new(0);
2503                 // Test through channels 2, 3, 5, 8.
2504                 // Test shows that multiple hop hints are considered.
2505
2506                 // Disabling channels 6 & 7 by flags=2
2507                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
2508                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2509                         short_channel_id: 6,
2510                         timestamp: 2,
2511                         flags: 2, // to disable
2512                         cltv_expiry_delta: 0,
2513                         htlc_minimum_msat: 0,
2514                         htlc_maximum_msat: OptionalField::Absent,
2515                         fee_base_msat: 0,
2516                         fee_proportional_millionths: 0,
2517                         excess_data: Vec::new()
2518                 });
2519                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
2520                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2521                         short_channel_id: 7,
2522                         timestamp: 2,
2523                         flags: 2, // to disable
2524                         cltv_expiry_delta: 0,
2525                         htlc_minimum_msat: 0,
2526                         htlc_maximum_msat: OptionalField::Absent,
2527                         fee_base_msat: 0,
2528                         fee_proportional_millionths: 0,
2529                         excess_data: Vec::new()
2530                 });
2531
2532                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &multi_hint_last_hops(&nodes).iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2533                 assert_eq!(route.paths[0].len(), 4);
2534
2535                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2536                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2537                 assert_eq!(route.paths[0][0].fee_msat, 200);
2538                 assert_eq!(route.paths[0][0].cltv_expiry_delta, 1025);
2539                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2540                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2541
2542                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2543                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2544                 assert_eq!(route.paths[0][1].fee_msat, 100);
2545                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 1281);
2546                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2547                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2548
2549                 assert_eq!(route.paths[0][2].pubkey, nodes[3]);
2550                 assert_eq!(route.paths[0][2].short_channel_id, 5);
2551                 assert_eq!(route.paths[0][2].fee_msat, 0);
2552                 assert_eq!(route.paths[0][2].cltv_expiry_delta, 2049);
2553                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(4));
2554                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &Vec::<u8>::new());
2555
2556                 assert_eq!(route.paths[0][3].pubkey, nodes[6]);
2557                 assert_eq!(route.paths[0][3].short_channel_id, 8);
2558                 assert_eq!(route.paths[0][3].fee_msat, 100);
2559                 assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
2560                 assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2561                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2562         }
2563
2564         fn last_hops_with_public_channel(nodes: &Vec<PublicKey>) -> Vec<RouteHint> {
2565                 let zero_fees = RoutingFees {
2566                         base_msat: 0,
2567                         proportional_millionths: 0,
2568                 };
2569                 vec![RouteHint(vec![RouteHintHop {
2570                         src_node_id: nodes[4],
2571                         short_channel_id: 11,
2572                         fees: zero_fees,
2573                         cltv_expiry_delta: (11 << 8) | 1,
2574                         htlc_minimum_msat: None,
2575                         htlc_maximum_msat: None,
2576                 }, RouteHintHop {
2577                         src_node_id: nodes[3],
2578                         short_channel_id: 8,
2579                         fees: zero_fees,
2580                         cltv_expiry_delta: (8 << 8) | 1,
2581                         htlc_minimum_msat: None,
2582                         htlc_maximum_msat: None,
2583                 }]), RouteHint(vec![RouteHintHop {
2584                         src_node_id: nodes[4],
2585                         short_channel_id: 9,
2586                         fees: RoutingFees {
2587                                 base_msat: 1001,
2588                                 proportional_millionths: 0,
2589                         },
2590                         cltv_expiry_delta: (9 << 8) | 1,
2591                         htlc_minimum_msat: None,
2592                         htlc_maximum_msat: None,
2593                 }]), RouteHint(vec![RouteHintHop {
2594                         src_node_id: nodes[5],
2595                         short_channel_id: 10,
2596                         fees: zero_fees,
2597                         cltv_expiry_delta: (10 << 8) | 1,
2598                         htlc_minimum_msat: None,
2599                         htlc_maximum_msat: None,
2600                 }])]
2601         }
2602
2603         #[test]
2604         fn last_hops_with_public_channel_test() {
2605                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2606                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
2607                 let scorer = Scorer::new(0);
2608                 // This test shows that public routes can be present in the invoice
2609                 // which would be handled in the same manner.
2610
2611                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &last_hops_with_public_channel(&nodes).iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2612                 assert_eq!(route.paths[0].len(), 5);
2613
2614                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2615                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2616                 assert_eq!(route.paths[0][0].fee_msat, 100);
2617                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2618                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2619                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2620
2621                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2622                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2623                 assert_eq!(route.paths[0][1].fee_msat, 0);
2624                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (6 << 8) | 1);
2625                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2626                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2627
2628                 assert_eq!(route.paths[0][2].pubkey, nodes[4]);
2629                 assert_eq!(route.paths[0][2].short_channel_id, 6);
2630                 assert_eq!(route.paths[0][2].fee_msat, 0);
2631                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (11 << 8) | 1);
2632                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(5));
2633                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(6));
2634
2635                 assert_eq!(route.paths[0][3].pubkey, nodes[3]);
2636                 assert_eq!(route.paths[0][3].short_channel_id, 11);
2637                 assert_eq!(route.paths[0][3].fee_msat, 0);
2638                 assert_eq!(route.paths[0][3].cltv_expiry_delta, (8 << 8) | 1);
2639                 // If we have a peer in the node map, we'll use their features here since we don't have
2640                 // a way of figuring out their features from the invoice:
2641                 assert_eq!(route.paths[0][3].node_features.le_flags(), &id_to_feature_flags(4));
2642                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new());
2643
2644                 assert_eq!(route.paths[0][4].pubkey, nodes[6]);
2645                 assert_eq!(route.paths[0][4].short_channel_id, 8);
2646                 assert_eq!(route.paths[0][4].fee_msat, 100);
2647                 assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
2648                 assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2649                 assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2650         }
2651
2652         #[test]
2653         fn our_chans_last_hop_connect_test() {
2654                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
2655                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
2656                 let scorer = Scorer::new(0);
2657
2658                 // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
2659                 let our_chans = vec![get_channel_details(Some(42), nodes[3].clone(), InitFeatures::from_le_bytes(vec![0b11]), 250_000_000)];
2660                 let mut last_hops = last_hops(&nodes);
2661                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, Some(&our_chans.iter().collect::<Vec<_>>()), &last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2662                 assert_eq!(route.paths[0].len(), 2);
2663
2664                 assert_eq!(route.paths[0][0].pubkey, nodes[3]);
2665                 assert_eq!(route.paths[0][0].short_channel_id, 42);
2666                 assert_eq!(route.paths[0][0].fee_msat, 0);
2667                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (8 << 8) | 1);
2668                 assert_eq!(route.paths[0][0].node_features.le_flags(), &vec![0b11]);
2669                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &Vec::<u8>::new()); // No feature flags will meet the relevant-to-channel conversion
2670
2671                 assert_eq!(route.paths[0][1].pubkey, nodes[6]);
2672                 assert_eq!(route.paths[0][1].short_channel_id, 8);
2673                 assert_eq!(route.paths[0][1].fee_msat, 100);
2674                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
2675                 assert_eq!(route.paths[0][1].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2676                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2677
2678                 last_hops[0].0[0].fees.base_msat = 1000;
2679
2680                 // Revert to via 6 as the fee on 8 goes up
2681                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &last_hops.iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
2682                 assert_eq!(route.paths[0].len(), 4);
2683
2684                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2685                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2686                 assert_eq!(route.paths[0][0].fee_msat, 200); // fee increased as its % of value transferred across node
2687                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2688                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2689                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2690
2691                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2692                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2693                 assert_eq!(route.paths[0][1].fee_msat, 100);
2694                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (7 << 8) | 1);
2695                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2696                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2697
2698                 assert_eq!(route.paths[0][2].pubkey, nodes[5]);
2699                 assert_eq!(route.paths[0][2].short_channel_id, 7);
2700                 assert_eq!(route.paths[0][2].fee_msat, 0);
2701                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (10 << 8) | 1);
2702                 // If we have a peer in the node map, we'll use their features here since we don't have
2703                 // a way of figuring out their features from the invoice:
2704                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(6));
2705                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(7));
2706
2707                 assert_eq!(route.paths[0][3].pubkey, nodes[6]);
2708                 assert_eq!(route.paths[0][3].short_channel_id, 10);
2709                 assert_eq!(route.paths[0][3].fee_msat, 100);
2710                 assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
2711                 assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2712                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2713
2714                 // ...but still use 8 for larger payments as 6 has a variable feerate
2715                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &last_hops.iter().collect::<Vec<_>>(), 2000, 42, Arc::clone(&logger), &scorer).unwrap();
2716                 assert_eq!(route.paths[0].len(), 5);
2717
2718                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
2719                 assert_eq!(route.paths[0][0].short_channel_id, 2);
2720                 assert_eq!(route.paths[0][0].fee_msat, 3000);
2721                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
2722                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
2723                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
2724
2725                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
2726                 assert_eq!(route.paths[0][1].short_channel_id, 4);
2727                 assert_eq!(route.paths[0][1].fee_msat, 0);
2728                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (6 << 8) | 1);
2729                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
2730                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
2731
2732                 assert_eq!(route.paths[0][2].pubkey, nodes[4]);
2733                 assert_eq!(route.paths[0][2].short_channel_id, 6);
2734                 assert_eq!(route.paths[0][2].fee_msat, 0);
2735                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (11 << 8) | 1);
2736                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(5));
2737                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(6));
2738
2739                 assert_eq!(route.paths[0][3].pubkey, nodes[3]);
2740                 assert_eq!(route.paths[0][3].short_channel_id, 11);
2741                 assert_eq!(route.paths[0][3].fee_msat, 1000);
2742                 assert_eq!(route.paths[0][3].cltv_expiry_delta, (8 << 8) | 1);
2743                 // If we have a peer in the node map, we'll use their features here since we don't have
2744                 // a way of figuring out their features from the invoice:
2745                 assert_eq!(route.paths[0][3].node_features.le_flags(), &id_to_feature_flags(4));
2746                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &id_to_feature_flags(11));
2747
2748                 assert_eq!(route.paths[0][4].pubkey, nodes[6]);
2749                 assert_eq!(route.paths[0][4].short_channel_id, 8);
2750                 assert_eq!(route.paths[0][4].fee_msat, 2000);
2751                 assert_eq!(route.paths[0][4].cltv_expiry_delta, 42);
2752                 assert_eq!(route.paths[0][4].node_features.le_flags(), &Vec::<u8>::new()); // We dont pass flags in from invoices yet
2753                 assert_eq!(route.paths[0][4].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
2754         }
2755
2756         fn do_unannounced_path_test(last_hop_htlc_max: Option<u64>, last_hop_fee_prop: u32, outbound_capacity_msat: u64, route_val: u64) -> Result<Route, LightningError> {
2757                 let source_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 41).repeat(32)).unwrap()[..]).unwrap());
2758                 let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap());
2759                 let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap());
2760
2761                 // If we specify a channel to a middle hop, that overrides our local channel view and that gets used
2762                 let last_hops = RouteHint(vec![RouteHintHop {
2763                         src_node_id: middle_node_id,
2764                         short_channel_id: 8,
2765                         fees: RoutingFees {
2766                                 base_msat: 1000,
2767                                 proportional_millionths: last_hop_fee_prop,
2768                         },
2769                         cltv_expiry_delta: (8 << 8) | 1,
2770                         htlc_minimum_msat: None,
2771                         htlc_maximum_msat: last_hop_htlc_max,
2772                 }]);
2773                 let our_chans = vec![get_channel_details(Some(42), middle_node_id, InitFeatures::from_le_bytes(vec![0b11]), outbound_capacity_msat)];
2774                 let scorer = Scorer::new(0);
2775                 get_route(&source_node_id, &NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash()), &target_node_id, None, Some(&our_chans.iter().collect::<Vec<_>>()), &vec![&last_hops], route_val, 42, &test_utils::TestLogger::new(), &scorer)
2776         }
2777
2778         #[test]
2779         fn unannounced_path_test() {
2780                 // We should be able to send a payment to a destination without any help of a routing graph
2781                 // if we have a channel with a common counterparty that appears in the first and last hop
2782                 // hints.
2783                 let route = do_unannounced_path_test(None, 1, 2000000, 1000000).unwrap();
2784
2785                 let middle_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 42).repeat(32)).unwrap()[..]).unwrap());
2786                 let target_node_id = PublicKey::from_secret_key(&Secp256k1::new(), &SecretKey::from_slice(&hex::decode(format!("{:02}", 43).repeat(32)).unwrap()[..]).unwrap());
2787                 assert_eq!(route.paths[0].len(), 2);
2788
2789                 assert_eq!(route.paths[0][0].pubkey, middle_node_id);
2790                 assert_eq!(route.paths[0][0].short_channel_id, 42);
2791                 assert_eq!(route.paths[0][0].fee_msat, 1001);
2792                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (8 << 8) | 1);
2793                 assert_eq!(route.paths[0][0].node_features.le_flags(), &[0b11]);
2794                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
2795
2796                 assert_eq!(route.paths[0][1].pubkey, target_node_id);
2797                 assert_eq!(route.paths[0][1].short_channel_id, 8);
2798                 assert_eq!(route.paths[0][1].fee_msat, 1000000);
2799                 assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
2800                 assert_eq!(route.paths[0][1].node_features.le_flags(), &[0; 0]); // We dont pass flags in from invoices yet
2801                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &[0; 0]); // We can't learn any flags from invoices, sadly
2802         }
2803
2804         #[test]
2805         fn overflow_unannounced_path_test_liquidity_underflow() {
2806                 // Previously, when we had a last-hop hint connected directly to a first-hop channel, where
2807                 // the last-hop had a fee which overflowed a u64, we'd panic.
2808                 // This was due to us adding the first-hop from us unconditionally, causing us to think
2809                 // we'd built a path (as our node is in the "best candidate" set), when we had not.
2810                 // In this test, we previously hit a subtraction underflow due to having less available
2811                 // liquidity at the last hop than 0.
2812                 assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 0, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err());
2813         }
2814
2815         #[test]
2816         fn overflow_unannounced_path_test_feerate_overflow() {
2817                 // This tests for the same case as above, except instead of hitting a subtraction
2818                 // underflow, we hit a case where the fee charged at a hop overflowed.
2819                 assert!(do_unannounced_path_test(Some(21_000_000_0000_0000_000), 50000, 21_000_000_0000_0000_000, 21_000_000_0000_0000_000).is_err());
2820         }
2821
2822         #[test]
2823         fn available_amount_while_routing_test() {
2824                 // Tests whether we choose the correct available channel amount while routing.
2825
2826                 let (secp_ctx, mut net_graph_msg_handler, chain_monitor, logger) = build_graph();
2827                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
2828                 let scorer = Scorer::new(0);
2829
2830                 // We will use a simple single-path route from
2831                 // our node to node2 via node0: channels {1, 3}.
2832
2833                 // First disable all other paths.
2834                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2835                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2836                         short_channel_id: 2,
2837                         timestamp: 2,
2838                         flags: 2,
2839                         cltv_expiry_delta: 0,
2840                         htlc_minimum_msat: 0,
2841                         htlc_maximum_msat: OptionalField::Present(100_000),
2842                         fee_base_msat: 0,
2843                         fee_proportional_millionths: 0,
2844                         excess_data: Vec::new()
2845                 });
2846                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2847                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2848                         short_channel_id: 12,
2849                         timestamp: 2,
2850                         flags: 2,
2851                         cltv_expiry_delta: 0,
2852                         htlc_minimum_msat: 0,
2853                         htlc_maximum_msat: OptionalField::Present(100_000),
2854                         fee_base_msat: 0,
2855                         fee_proportional_millionths: 0,
2856                         excess_data: Vec::new()
2857                 });
2858
2859                 // Make the first channel (#1) very permissive,
2860                 // and we will be testing all limits on the second channel.
2861                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2862                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2863                         short_channel_id: 1,
2864                         timestamp: 2,
2865                         flags: 0,
2866                         cltv_expiry_delta: 0,
2867                         htlc_minimum_msat: 0,
2868                         htlc_maximum_msat: OptionalField::Present(1_000_000_000),
2869                         fee_base_msat: 0,
2870                         fee_proportional_millionths: 0,
2871                         excess_data: Vec::new()
2872                 });
2873
2874                 // First, let's see if routing works if we have absolutely no idea about the available amount.
2875                 // In this case, it should be set to 250_000 sats.
2876                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
2877                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2878                         short_channel_id: 3,
2879                         timestamp: 2,
2880                         flags: 0,
2881                         cltv_expiry_delta: 0,
2882                         htlc_minimum_msat: 0,
2883                         htlc_maximum_msat: OptionalField::Absent,
2884                         fee_base_msat: 0,
2885                         fee_proportional_millionths: 0,
2886                         excess_data: Vec::new()
2887                 });
2888
2889                 {
2890                         // Attempt to route more than available results in a failure.
2891                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2892                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 250_000_001, 42, Arc::clone(&logger), &scorer) {
2893                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
2894                         } else { panic!(); }
2895                 }
2896
2897                 {
2898                         // Now, attempt to route an exact amount we have should be fine.
2899                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2900                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 250_000_000, 42, Arc::clone(&logger), &scorer).unwrap();
2901                         assert_eq!(route.paths.len(), 1);
2902                         let path = route.paths.last().unwrap();
2903                         assert_eq!(path.len(), 2);
2904                         assert_eq!(path.last().unwrap().pubkey, nodes[2]);
2905                         assert_eq!(path.last().unwrap().fee_msat, 250_000_000);
2906                 }
2907
2908                 // Check that setting outbound_capacity_msat in first_hops limits the channels.
2909                 // Disable channel #1 and use another first hop.
2910                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2911                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2912                         short_channel_id: 1,
2913                         timestamp: 3,
2914                         flags: 2,
2915                         cltv_expiry_delta: 0,
2916                         htlc_minimum_msat: 0,
2917                         htlc_maximum_msat: OptionalField::Present(1_000_000_000),
2918                         fee_base_msat: 0,
2919                         fee_proportional_millionths: 0,
2920                         excess_data: Vec::new()
2921                 });
2922
2923                 // Now, limit the first_hop by the outbound_capacity_msat of 200_000 sats.
2924                 let our_chans = vec![get_channel_details(Some(42), nodes[0].clone(), InitFeatures::from_le_bytes(vec![0b11]), 200_000_000)];
2925
2926                 {
2927                         // Attempt to route more than available results in a failure.
2928                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2929                                         Some(InvoiceFeatures::known()), Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 200_000_001, 42, Arc::clone(&logger), &scorer) {
2930                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
2931                         } else { panic!(); }
2932                 }
2933
2934                 {
2935                         // Now, attempt to route an exact amount we have should be fine.
2936                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2937                                 Some(InvoiceFeatures::known()), Some(&our_chans.iter().collect::<Vec<_>>()), &Vec::new(), 200_000_000, 42, Arc::clone(&logger), &scorer).unwrap();
2938                         assert_eq!(route.paths.len(), 1);
2939                         let path = route.paths.last().unwrap();
2940                         assert_eq!(path.len(), 2);
2941                         assert_eq!(path.last().unwrap().pubkey, nodes[2]);
2942                         assert_eq!(path.last().unwrap().fee_msat, 200_000_000);
2943                 }
2944
2945                 // Enable channel #1 back.
2946                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
2947                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2948                         short_channel_id: 1,
2949                         timestamp: 4,
2950                         flags: 0,
2951                         cltv_expiry_delta: 0,
2952                         htlc_minimum_msat: 0,
2953                         htlc_maximum_msat: OptionalField::Present(1_000_000_000),
2954                         fee_base_msat: 0,
2955                         fee_proportional_millionths: 0,
2956                         excess_data: Vec::new()
2957                 });
2958
2959
2960                 // Now let's see if routing works if we know only htlc_maximum_msat.
2961                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
2962                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2963                         short_channel_id: 3,
2964                         timestamp: 3,
2965                         flags: 0,
2966                         cltv_expiry_delta: 0,
2967                         htlc_minimum_msat: 0,
2968                         htlc_maximum_msat: OptionalField::Present(15_000),
2969                         fee_base_msat: 0,
2970                         fee_proportional_millionths: 0,
2971                         excess_data: Vec::new()
2972                 });
2973
2974                 {
2975                         // Attempt to route more than available results in a failure.
2976                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2977                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 15_001, 42, Arc::clone(&logger), &scorer) {
2978                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
2979                         } else { panic!(); }
2980                 }
2981
2982                 {
2983                         // Now, attempt to route an exact amount we have should be fine.
2984                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
2985                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 15_000, 42, Arc::clone(&logger), &scorer).unwrap();
2986                         assert_eq!(route.paths.len(), 1);
2987                         let path = route.paths.last().unwrap();
2988                         assert_eq!(path.len(), 2);
2989                         assert_eq!(path.last().unwrap().pubkey, nodes[2]);
2990                         assert_eq!(path.last().unwrap().fee_msat, 15_000);
2991                 }
2992
2993                 // Now let's see if routing works if we know only capacity from the UTXO.
2994
2995                 // We can't change UTXO capacity on the fly, so we'll disable
2996                 // the existing channel and add another one with the capacity we need.
2997                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
2998                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
2999                         short_channel_id: 3,
3000                         timestamp: 4,
3001                         flags: 2,
3002                         cltv_expiry_delta: 0,
3003                         htlc_minimum_msat: 0,
3004                         htlc_maximum_msat: OptionalField::Absent,
3005                         fee_base_msat: 0,
3006                         fee_proportional_millionths: 0,
3007                         excess_data: Vec::new()
3008                 });
3009
3010                 let good_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
3011                 .push_slice(&PublicKey::from_secret_key(&secp_ctx, &privkeys[0]).serialize())
3012                 .push_slice(&PublicKey::from_secret_key(&secp_ctx, &privkeys[2]).serialize())
3013                 .push_opcode(opcodes::all::OP_PUSHNUM_2)
3014                 .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
3015
3016                 *chain_monitor.utxo_ret.lock().unwrap() = Ok(TxOut { value: 15, script_pubkey: good_script.clone() });
3017                 net_graph_msg_handler.add_chain_access(Some(chain_monitor));
3018
3019                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 333);
3020                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3021                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3022                         short_channel_id: 333,
3023                         timestamp: 1,
3024                         flags: 0,
3025                         cltv_expiry_delta: (3 << 8) | 1,
3026                         htlc_minimum_msat: 0,
3027                         htlc_maximum_msat: OptionalField::Absent,
3028                         fee_base_msat: 0,
3029                         fee_proportional_millionths: 0,
3030                         excess_data: Vec::new()
3031                 });
3032                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3033                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3034                         short_channel_id: 333,
3035                         timestamp: 1,
3036                         flags: 1,
3037                         cltv_expiry_delta: (3 << 8) | 2,
3038                         htlc_minimum_msat: 0,
3039                         htlc_maximum_msat: OptionalField::Absent,
3040                         fee_base_msat: 100,
3041                         fee_proportional_millionths: 0,
3042                         excess_data: Vec::new()
3043                 });
3044
3045                 {
3046                         // Attempt to route more than available results in a failure.
3047                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3048                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 15_001, 42, Arc::clone(&logger), &scorer) {
3049                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3050                         } else { panic!(); }
3051                 }
3052
3053                 {
3054                         // Now, attempt to route an exact amount we have should be fine.
3055                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3056                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 15_000, 42, Arc::clone(&logger), &scorer).unwrap();
3057                         assert_eq!(route.paths.len(), 1);
3058                         let path = route.paths.last().unwrap();
3059                         assert_eq!(path.len(), 2);
3060                         assert_eq!(path.last().unwrap().pubkey, nodes[2]);
3061                         assert_eq!(path.last().unwrap().fee_msat, 15_000);
3062                 }
3063
3064                 // Now let's see if routing chooses htlc_maximum_msat over UTXO capacity.
3065                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3066                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3067                         short_channel_id: 333,
3068                         timestamp: 6,
3069                         flags: 0,
3070                         cltv_expiry_delta: 0,
3071                         htlc_minimum_msat: 0,
3072                         htlc_maximum_msat: OptionalField::Present(10_000),
3073                         fee_base_msat: 0,
3074                         fee_proportional_millionths: 0,
3075                         excess_data: Vec::new()
3076                 });
3077
3078                 {
3079                         // Attempt to route more than available results in a failure.
3080                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3081                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 10_001, 42, Arc::clone(&logger), &scorer) {
3082                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3083                         } else { panic!(); }
3084                 }
3085
3086                 {
3087                         // Now, attempt to route an exact amount we have should be fine.
3088                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3089                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 10_000, 42, Arc::clone(&logger), &scorer).unwrap();
3090                         assert_eq!(route.paths.len(), 1);
3091                         let path = route.paths.last().unwrap();
3092                         assert_eq!(path.len(), 2);
3093                         assert_eq!(path.last().unwrap().pubkey, nodes[2]);
3094                         assert_eq!(path.last().unwrap().fee_msat, 10_000);
3095                 }
3096         }
3097
3098         #[test]
3099         fn available_liquidity_last_hop_test() {
3100                 // Check that available liquidity properly limits the path even when only
3101                 // one of the latter hops is limited.
3102                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3103                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3104                 let scorer = Scorer::new(0);
3105
3106                 // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
3107                 // {12, 13, 11} have the capacities of 100, {6} has a capacity of 50.
3108                 // Total capacity: 50 sats.
3109
3110                 // Disable other potential paths.
3111                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3112                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3113                         short_channel_id: 2,
3114                         timestamp: 2,
3115                         flags: 2,
3116                         cltv_expiry_delta: 0,
3117                         htlc_minimum_msat: 0,
3118                         htlc_maximum_msat: OptionalField::Present(100_000),
3119                         fee_base_msat: 0,
3120                         fee_proportional_millionths: 0,
3121                         excess_data: Vec::new()
3122                 });
3123                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3124                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3125                         short_channel_id: 7,
3126                         timestamp: 2,
3127                         flags: 2,
3128                         cltv_expiry_delta: 0,
3129                         htlc_minimum_msat: 0,
3130                         htlc_maximum_msat: OptionalField::Present(100_000),
3131                         fee_base_msat: 0,
3132                         fee_proportional_millionths: 0,
3133                         excess_data: Vec::new()
3134                 });
3135
3136                 // Limit capacities
3137
3138                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3139                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3140                         short_channel_id: 12,
3141                         timestamp: 2,
3142                         flags: 0,
3143                         cltv_expiry_delta: 0,
3144                         htlc_minimum_msat: 0,
3145                         htlc_maximum_msat: OptionalField::Present(100_000),
3146                         fee_base_msat: 0,
3147                         fee_proportional_millionths: 0,
3148                         excess_data: Vec::new()
3149                 });
3150                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3151                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3152                         short_channel_id: 13,
3153                         timestamp: 2,
3154                         flags: 0,
3155                         cltv_expiry_delta: 0,
3156                         htlc_minimum_msat: 0,
3157                         htlc_maximum_msat: OptionalField::Present(100_000),
3158                         fee_base_msat: 0,
3159                         fee_proportional_millionths: 0,
3160                         excess_data: Vec::new()
3161                 });
3162
3163                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3164                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3165                         short_channel_id: 6,
3166                         timestamp: 2,
3167                         flags: 0,
3168                         cltv_expiry_delta: 0,
3169                         htlc_minimum_msat: 0,
3170                         htlc_maximum_msat: OptionalField::Present(50_000),
3171                         fee_base_msat: 0,
3172                         fee_proportional_millionths: 0,
3173                         excess_data: Vec::new()
3174                 });
3175                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
3176                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3177                         short_channel_id: 11,
3178                         timestamp: 2,
3179                         flags: 0,
3180                         cltv_expiry_delta: 0,
3181                         htlc_minimum_msat: 0,
3182                         htlc_maximum_msat: OptionalField::Present(100_000),
3183                         fee_base_msat: 0,
3184                         fee_proportional_millionths: 0,
3185                         excess_data: Vec::new()
3186                 });
3187                 {
3188                         // Attempt to route more than available results in a failure.
3189                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3190                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 60_000, 42, Arc::clone(&logger), &scorer) {
3191                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3192                         } else { panic!(); }
3193                 }
3194
3195                 {
3196                         // Now, attempt to route 49 sats (just a bit below the capacity).
3197                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3198                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 49_000, 42, Arc::clone(&logger), &scorer).unwrap();
3199                         assert_eq!(route.paths.len(), 1);
3200                         let mut total_amount_paid_msat = 0;
3201                         for path in &route.paths {
3202                                 assert_eq!(path.len(), 4);
3203                                 assert_eq!(path.last().unwrap().pubkey, nodes[3]);
3204                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3205                         }
3206                         assert_eq!(total_amount_paid_msat, 49_000);
3207                 }
3208
3209                 {
3210                         // Attempt to route an exact amount is also fine
3211                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3212                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 50_000, 42, Arc::clone(&logger), &scorer).unwrap();
3213                         assert_eq!(route.paths.len(), 1);
3214                         let mut total_amount_paid_msat = 0;
3215                         for path in &route.paths {
3216                                 assert_eq!(path.len(), 4);
3217                                 assert_eq!(path.last().unwrap().pubkey, nodes[3]);
3218                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3219                         }
3220                         assert_eq!(total_amount_paid_msat, 50_000);
3221                 }
3222         }
3223
3224         #[test]
3225         fn ignore_fee_first_hop_test() {
3226                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3227                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3228                 let scorer = Scorer::new(0);
3229
3230                 // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50).
3231                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3232                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3233                         short_channel_id: 1,
3234                         timestamp: 2,
3235                         flags: 0,
3236                         cltv_expiry_delta: 0,
3237                         htlc_minimum_msat: 0,
3238                         htlc_maximum_msat: OptionalField::Present(100_000),
3239                         fee_base_msat: 1_000_000,
3240                         fee_proportional_millionths: 0,
3241                         excess_data: Vec::new()
3242                 });
3243                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3244                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3245                         short_channel_id: 3,
3246                         timestamp: 2,
3247                         flags: 0,
3248                         cltv_expiry_delta: 0,
3249                         htlc_minimum_msat: 0,
3250                         htlc_maximum_msat: OptionalField::Present(50_000),
3251                         fee_base_msat: 0,
3252                         fee_proportional_millionths: 0,
3253                         excess_data: Vec::new()
3254                 });
3255
3256                 {
3257                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 50_000, 42, Arc::clone(&logger), &scorer).unwrap();
3258                         assert_eq!(route.paths.len(), 1);
3259                         let mut total_amount_paid_msat = 0;
3260                         for path in &route.paths {
3261                                 assert_eq!(path.len(), 2);
3262                                 assert_eq!(path.last().unwrap().pubkey, nodes[2]);
3263                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3264                         }
3265                         assert_eq!(total_amount_paid_msat, 50_000);
3266                 }
3267         }
3268
3269         #[test]
3270         fn simple_mpp_route_test() {
3271                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3272                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3273                 let scorer = Scorer::new(0);
3274
3275                 // We need a route consisting of 3 paths:
3276                 // From our node to node2 via node0, node7, node1 (three paths one hop each).
3277                 // To achieve this, the amount being transferred should be around
3278                 // the total capacity of these 3 paths.
3279
3280                 // First, we set limits on these (previously unlimited) channels.
3281                 // Their aggregate capacity will be 50 + 60 + 180 = 290 sats.
3282
3283                 // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50).
3284                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3285                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3286                         short_channel_id: 1,
3287                         timestamp: 2,
3288                         flags: 0,
3289                         cltv_expiry_delta: 0,
3290                         htlc_minimum_msat: 0,
3291                         htlc_maximum_msat: OptionalField::Present(100_000),
3292                         fee_base_msat: 0,
3293                         fee_proportional_millionths: 0,
3294                         excess_data: Vec::new()
3295                 });
3296                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3297                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3298                         short_channel_id: 3,
3299                         timestamp: 2,
3300                         flags: 0,
3301                         cltv_expiry_delta: 0,
3302                         htlc_minimum_msat: 0,
3303                         htlc_maximum_msat: OptionalField::Present(50_000),
3304                         fee_base_msat: 0,
3305                         fee_proportional_millionths: 0,
3306                         excess_data: Vec::new()
3307                 });
3308
3309                 // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats
3310                 // (total limit 60).
3311                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3312                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3313                         short_channel_id: 12,
3314                         timestamp: 2,
3315                         flags: 0,
3316                         cltv_expiry_delta: 0,
3317                         htlc_minimum_msat: 0,
3318                         htlc_maximum_msat: OptionalField::Present(60_000),
3319                         fee_base_msat: 0,
3320                         fee_proportional_millionths: 0,
3321                         excess_data: Vec::new()
3322                 });
3323                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3324                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3325                         short_channel_id: 13,
3326                         timestamp: 2,
3327                         flags: 0,
3328                         cltv_expiry_delta: 0,
3329                         htlc_minimum_msat: 0,
3330                         htlc_maximum_msat: OptionalField::Present(60_000),
3331                         fee_base_msat: 0,
3332                         fee_proportional_millionths: 0,
3333                         excess_data: Vec::new()
3334                 });
3335
3336                 // Path via node1 is channels {2, 4}. Limit them to 200 and 180 sats
3337                 // (total capacity 180 sats).
3338                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3339                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3340                         short_channel_id: 2,
3341                         timestamp: 2,
3342                         flags: 0,
3343                         cltv_expiry_delta: 0,
3344                         htlc_minimum_msat: 0,
3345                         htlc_maximum_msat: OptionalField::Present(200_000),
3346                         fee_base_msat: 0,
3347                         fee_proportional_millionths: 0,
3348                         excess_data: Vec::new()
3349                 });
3350                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
3351                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3352                         short_channel_id: 4,
3353                         timestamp: 2,
3354                         flags: 0,
3355                         cltv_expiry_delta: 0,
3356                         htlc_minimum_msat: 0,
3357                         htlc_maximum_msat: OptionalField::Present(180_000),
3358                         fee_base_msat: 0,
3359                         fee_proportional_millionths: 0,
3360                         excess_data: Vec::new()
3361                 });
3362
3363                 {
3364                         // Attempt to route more than available results in a failure.
3365                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph,
3366                                         &nodes[2], Some(InvoiceFeatures::known()), None, &Vec::new(), 300_000, 42, Arc::clone(&logger), &scorer) {
3367                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3368                         } else { panic!(); }
3369                 }
3370
3371                 {
3372                         // Now, attempt to route 250 sats (just a bit below the capacity).
3373                         // Our algorithm should provide us with these 3 paths.
3374                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3375                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 250_000, 42, Arc::clone(&logger), &scorer).unwrap();
3376                         assert_eq!(route.paths.len(), 3);
3377                         let mut total_amount_paid_msat = 0;
3378                         for path in &route.paths {
3379                                 assert_eq!(path.len(), 2);
3380                                 assert_eq!(path.last().unwrap().pubkey, nodes[2]);
3381                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3382                         }
3383                         assert_eq!(total_amount_paid_msat, 250_000);
3384                 }
3385
3386                 {
3387                         // Attempt to route an exact amount is also fine
3388                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3389                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 290_000, 42, Arc::clone(&logger), &scorer).unwrap();
3390                         assert_eq!(route.paths.len(), 3);
3391                         let mut total_amount_paid_msat = 0;
3392                         for path in &route.paths {
3393                                 assert_eq!(path.len(), 2);
3394                                 assert_eq!(path.last().unwrap().pubkey, nodes[2]);
3395                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3396                         }
3397                         assert_eq!(total_amount_paid_msat, 290_000);
3398                 }
3399         }
3400
3401         #[test]
3402         fn long_mpp_route_test() {
3403                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3404                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3405                 let scorer = Scorer::new(0);
3406
3407                 // We need a route consisting of 3 paths:
3408                 // From our node to node3 via {node0, node2}, {node7, node2, node4} and {node7, node2}.
3409                 // Note that these paths overlap (channels 5, 12, 13).
3410                 // We will route 300 sats.
3411                 // Each path will have 100 sats capacity, those channels which
3412                 // are used twice will have 200 sats capacity.
3413
3414                 // Disable other potential paths.
3415                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3416                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3417                         short_channel_id: 2,
3418                         timestamp: 2,
3419                         flags: 2,
3420                         cltv_expiry_delta: 0,
3421                         htlc_minimum_msat: 0,
3422                         htlc_maximum_msat: OptionalField::Present(100_000),
3423                         fee_base_msat: 0,
3424                         fee_proportional_millionths: 0,
3425                         excess_data: Vec::new()
3426                 });
3427                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3428                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3429                         short_channel_id: 7,
3430                         timestamp: 2,
3431                         flags: 2,
3432                         cltv_expiry_delta: 0,
3433                         htlc_minimum_msat: 0,
3434                         htlc_maximum_msat: OptionalField::Present(100_000),
3435                         fee_base_msat: 0,
3436                         fee_proportional_millionths: 0,
3437                         excess_data: Vec::new()
3438                 });
3439
3440                 // Path via {node0, node2} is channels {1, 3, 5}.
3441                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3442                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3443                         short_channel_id: 1,
3444                         timestamp: 2,
3445                         flags: 0,
3446                         cltv_expiry_delta: 0,
3447                         htlc_minimum_msat: 0,
3448                         htlc_maximum_msat: OptionalField::Present(100_000),
3449                         fee_base_msat: 0,
3450                         fee_proportional_millionths: 0,
3451                         excess_data: Vec::new()
3452                 });
3453                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3454                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3455                         short_channel_id: 3,
3456                         timestamp: 2,
3457                         flags: 0,
3458                         cltv_expiry_delta: 0,
3459                         htlc_minimum_msat: 0,
3460                         htlc_maximum_msat: OptionalField::Present(100_000),
3461                         fee_base_msat: 0,
3462                         fee_proportional_millionths: 0,
3463                         excess_data: Vec::new()
3464                 });
3465
3466                 // Capacity of 200 sats because this channel will be used by 3rd path as well.
3467                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
3468                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3469                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3470                         short_channel_id: 5,
3471                         timestamp: 2,
3472                         flags: 0,
3473                         cltv_expiry_delta: 0,
3474                         htlc_minimum_msat: 0,
3475                         htlc_maximum_msat: OptionalField::Present(200_000),
3476                         fee_base_msat: 0,
3477                         fee_proportional_millionths: 0,
3478                         excess_data: Vec::new()
3479                 });
3480
3481                 // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
3482                 // Add 100 sats to the capacities of {12, 13}, because these channels
3483                 // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats.
3484                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3485                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3486                         short_channel_id: 12,
3487                         timestamp: 2,
3488                         flags: 0,
3489                         cltv_expiry_delta: 0,
3490                         htlc_minimum_msat: 0,
3491                         htlc_maximum_msat: OptionalField::Present(200_000),
3492                         fee_base_msat: 0,
3493                         fee_proportional_millionths: 0,
3494                         excess_data: Vec::new()
3495                 });
3496                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3497                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3498                         short_channel_id: 13,
3499                         timestamp: 2,
3500                         flags: 0,
3501                         cltv_expiry_delta: 0,
3502                         htlc_minimum_msat: 0,
3503                         htlc_maximum_msat: OptionalField::Present(200_000),
3504                         fee_base_msat: 0,
3505                         fee_proportional_millionths: 0,
3506                         excess_data: Vec::new()
3507                 });
3508
3509                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3510                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3511                         short_channel_id: 6,
3512                         timestamp: 2,
3513                         flags: 0,
3514                         cltv_expiry_delta: 0,
3515                         htlc_minimum_msat: 0,
3516                         htlc_maximum_msat: OptionalField::Present(100_000),
3517                         fee_base_msat: 0,
3518                         fee_proportional_millionths: 0,
3519                         excess_data: Vec::new()
3520                 });
3521                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
3522                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3523                         short_channel_id: 11,
3524                         timestamp: 2,
3525                         flags: 0,
3526                         cltv_expiry_delta: 0,
3527                         htlc_minimum_msat: 0,
3528                         htlc_maximum_msat: OptionalField::Present(100_000),
3529                         fee_base_msat: 0,
3530                         fee_proportional_millionths: 0,
3531                         excess_data: Vec::new()
3532                 });
3533
3534                 // Path via {node7, node2} is channels {12, 13, 5}.
3535                 // We already limited them to 200 sats (they are used twice for 100 sats).
3536                 // Nothing to do here.
3537
3538                 {
3539                         // Attempt to route more than available results in a failure.
3540                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3541                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 350_000, 42, Arc::clone(&logger), &scorer) {
3542                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3543                         } else { panic!(); }
3544                 }
3545
3546                 {
3547                         // Now, attempt to route 300 sats (exact amount we can route).
3548                         // Our algorithm should provide us with these 3 paths, 100 sats each.
3549                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3550                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 300_000, 42, Arc::clone(&logger), &scorer).unwrap();
3551                         assert_eq!(route.paths.len(), 3);
3552
3553                         let mut total_amount_paid_msat = 0;
3554                         for path in &route.paths {
3555                                 assert_eq!(path.last().unwrap().pubkey, nodes[3]);
3556                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3557                         }
3558                         assert_eq!(total_amount_paid_msat, 300_000);
3559                 }
3560
3561         }
3562
3563         #[test]
3564         fn mpp_cheaper_route_test() {
3565                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3566                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3567                 let scorer = Scorer::new(0);
3568
3569                 // This test checks that if we have two cheaper paths and one more expensive path,
3570                 // so that liquidity-wise any 2 of 3 combination is sufficient,
3571                 // two cheaper paths will be taken.
3572                 // These paths have equal available liquidity.
3573
3574                 // We need a combination of 3 paths:
3575                 // From our node to node3 via {node0, node2}, {node7, node2, node4} and {node7, node2}.
3576                 // Note that these paths overlap (channels 5, 12, 13).
3577                 // Each path will have 100 sats capacity, those channels which
3578                 // are used twice will have 200 sats capacity.
3579
3580                 // Disable other potential paths.
3581                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3582                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3583                         short_channel_id: 2,
3584                         timestamp: 2,
3585                         flags: 2,
3586                         cltv_expiry_delta: 0,
3587                         htlc_minimum_msat: 0,
3588                         htlc_maximum_msat: OptionalField::Present(100_000),
3589                         fee_base_msat: 0,
3590                         fee_proportional_millionths: 0,
3591                         excess_data: Vec::new()
3592                 });
3593                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3594                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3595                         short_channel_id: 7,
3596                         timestamp: 2,
3597                         flags: 2,
3598                         cltv_expiry_delta: 0,
3599                         htlc_minimum_msat: 0,
3600                         htlc_maximum_msat: OptionalField::Present(100_000),
3601                         fee_base_msat: 0,
3602                         fee_proportional_millionths: 0,
3603                         excess_data: Vec::new()
3604                 });
3605
3606                 // Path via {node0, node2} is channels {1, 3, 5}.
3607                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3608                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3609                         short_channel_id: 1,
3610                         timestamp: 2,
3611                         flags: 0,
3612                         cltv_expiry_delta: 0,
3613                         htlc_minimum_msat: 0,
3614                         htlc_maximum_msat: OptionalField::Present(100_000),
3615                         fee_base_msat: 0,
3616                         fee_proportional_millionths: 0,
3617                         excess_data: Vec::new()
3618                 });
3619                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3620                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3621                         short_channel_id: 3,
3622                         timestamp: 2,
3623                         flags: 0,
3624                         cltv_expiry_delta: 0,
3625                         htlc_minimum_msat: 0,
3626                         htlc_maximum_msat: OptionalField::Present(100_000),
3627                         fee_base_msat: 0,
3628                         fee_proportional_millionths: 0,
3629                         excess_data: Vec::new()
3630                 });
3631
3632                 // Capacity of 200 sats because this channel will be used by 3rd path as well.
3633                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
3634                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3635                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3636                         short_channel_id: 5,
3637                         timestamp: 2,
3638                         flags: 0,
3639                         cltv_expiry_delta: 0,
3640                         htlc_minimum_msat: 0,
3641                         htlc_maximum_msat: OptionalField::Present(200_000),
3642                         fee_base_msat: 0,
3643                         fee_proportional_millionths: 0,
3644                         excess_data: Vec::new()
3645                 });
3646
3647                 // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
3648                 // Add 100 sats to the capacities of {12, 13}, because these channels
3649                 // are also used for 3rd path. 100 sats for the rest. Total capacity: 100 sats.
3650                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3651                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3652                         short_channel_id: 12,
3653                         timestamp: 2,
3654                         flags: 0,
3655                         cltv_expiry_delta: 0,
3656                         htlc_minimum_msat: 0,
3657                         htlc_maximum_msat: OptionalField::Present(200_000),
3658                         fee_base_msat: 0,
3659                         fee_proportional_millionths: 0,
3660                         excess_data: Vec::new()
3661                 });
3662                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3663                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3664                         short_channel_id: 13,
3665                         timestamp: 2,
3666                         flags: 0,
3667                         cltv_expiry_delta: 0,
3668                         htlc_minimum_msat: 0,
3669                         htlc_maximum_msat: OptionalField::Present(200_000),
3670                         fee_base_msat: 0,
3671                         fee_proportional_millionths: 0,
3672                         excess_data: Vec::new()
3673                 });
3674
3675                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3676                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3677                         short_channel_id: 6,
3678                         timestamp: 2,
3679                         flags: 0,
3680                         cltv_expiry_delta: 0,
3681                         htlc_minimum_msat: 0,
3682                         htlc_maximum_msat: OptionalField::Present(100_000),
3683                         fee_base_msat: 1_000,
3684                         fee_proportional_millionths: 0,
3685                         excess_data: Vec::new()
3686                 });
3687                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
3688                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3689                         short_channel_id: 11,
3690                         timestamp: 2,
3691                         flags: 0,
3692                         cltv_expiry_delta: 0,
3693                         htlc_minimum_msat: 0,
3694                         htlc_maximum_msat: OptionalField::Present(100_000),
3695                         fee_base_msat: 0,
3696                         fee_proportional_millionths: 0,
3697                         excess_data: Vec::new()
3698                 });
3699
3700                 // Path via {node7, node2} is channels {12, 13, 5}.
3701                 // We already limited them to 200 sats (they are used twice for 100 sats).
3702                 // Nothing to do here.
3703
3704                 {
3705                         // Now, attempt to route 180 sats.
3706                         // Our algorithm should provide us with these 2 paths.
3707                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3708                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 180_000, 42, Arc::clone(&logger), &scorer).unwrap();
3709                         assert_eq!(route.paths.len(), 2);
3710
3711                         let mut total_value_transferred_msat = 0;
3712                         let mut total_paid_msat = 0;
3713                         for path in &route.paths {
3714                                 assert_eq!(path.last().unwrap().pubkey, nodes[3]);
3715                                 total_value_transferred_msat += path.last().unwrap().fee_msat;
3716                                 for hop in path {
3717                                         total_paid_msat += hop.fee_msat;
3718                                 }
3719                         }
3720                         // If we paid fee, this would be higher.
3721                         assert_eq!(total_value_transferred_msat, 180_000);
3722                         let total_fees_paid = total_paid_msat - total_value_transferred_msat;
3723                         assert_eq!(total_fees_paid, 0);
3724                 }
3725         }
3726
3727         #[test]
3728         fn fees_on_mpp_route_test() {
3729                 // This test makes sure that MPP algorithm properly takes into account
3730                 // fees charged on the channels, by making the fees impactful:
3731                 // if the fee is not properly accounted for, the behavior is different.
3732                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3733                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3734                 let scorer = Scorer::new(0);
3735
3736                 // We need a route consisting of 2 paths:
3737                 // From our node to node3 via {node0, node2} and {node7, node2, node4}.
3738                 // We will route 200 sats, Each path will have 100 sats capacity.
3739
3740                 // This test is not particularly stable: e.g.,
3741                 // there's a way to route via {node0, node2, node4}.
3742                 // It works while pathfinding is deterministic, but can be broken otherwise.
3743                 // It's fine to ignore this concern for now.
3744
3745                 // Disable other potential paths.
3746                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3747                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3748                         short_channel_id: 2,
3749                         timestamp: 2,
3750                         flags: 2,
3751                         cltv_expiry_delta: 0,
3752                         htlc_minimum_msat: 0,
3753                         htlc_maximum_msat: OptionalField::Present(100_000),
3754                         fee_base_msat: 0,
3755                         fee_proportional_millionths: 0,
3756                         excess_data: Vec::new()
3757                 });
3758
3759                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3760                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3761                         short_channel_id: 7,
3762                         timestamp: 2,
3763                         flags: 2,
3764                         cltv_expiry_delta: 0,
3765                         htlc_minimum_msat: 0,
3766                         htlc_maximum_msat: OptionalField::Present(100_000),
3767                         fee_base_msat: 0,
3768                         fee_proportional_millionths: 0,
3769                         excess_data: Vec::new()
3770                 });
3771
3772                 // Path via {node0, node2} is channels {1, 3, 5}.
3773                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3774                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3775                         short_channel_id: 1,
3776                         timestamp: 2,
3777                         flags: 0,
3778                         cltv_expiry_delta: 0,
3779                         htlc_minimum_msat: 0,
3780                         htlc_maximum_msat: OptionalField::Present(100_000),
3781                         fee_base_msat: 0,
3782                         fee_proportional_millionths: 0,
3783                         excess_data: Vec::new()
3784                 });
3785                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3786                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3787                         short_channel_id: 3,
3788                         timestamp: 2,
3789                         flags: 0,
3790                         cltv_expiry_delta: 0,
3791                         htlc_minimum_msat: 0,
3792                         htlc_maximum_msat: OptionalField::Present(100_000),
3793                         fee_base_msat: 0,
3794                         fee_proportional_millionths: 0,
3795                         excess_data: Vec::new()
3796                 });
3797
3798                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
3799                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3800                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3801                         short_channel_id: 5,
3802                         timestamp: 2,
3803                         flags: 0,
3804                         cltv_expiry_delta: 0,
3805                         htlc_minimum_msat: 0,
3806                         htlc_maximum_msat: OptionalField::Present(100_000),
3807                         fee_base_msat: 0,
3808                         fee_proportional_millionths: 0,
3809                         excess_data: Vec::new()
3810                 });
3811
3812                 // Path via {node7, node2, node4} is channels {12, 13, 6, 11}.
3813                 // All channels should be 100 sats capacity. But for the fee experiment,
3814                 // we'll add absolute fee of 150 sats paid for the use channel 6 (paid to node2 on channel 13).
3815                 // Since channel 12 allows to deliver only 250 sats to channel 13, channel 13 can transfer only
3816                 // 100 sats (and pay 150 sats in fees for the use of channel 6),
3817                 // so no matter how large are other channels,
3818                 // the whole path will be limited by 100 sats with just these 2 conditions:
3819                 // - channel 12 capacity is 250 sats
3820                 // - fee for channel 6 is 150 sats
3821                 // Let's test this by enforcing these 2 conditions and removing other limits.
3822                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3823                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3824                         short_channel_id: 12,
3825                         timestamp: 2,
3826                         flags: 0,
3827                         cltv_expiry_delta: 0,
3828                         htlc_minimum_msat: 0,
3829                         htlc_maximum_msat: OptionalField::Present(250_000),
3830                         fee_base_msat: 0,
3831                         fee_proportional_millionths: 0,
3832                         excess_data: Vec::new()
3833                 });
3834                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3835                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3836                         short_channel_id: 13,
3837                         timestamp: 2,
3838                         flags: 0,
3839                         cltv_expiry_delta: 0,
3840                         htlc_minimum_msat: 0,
3841                         htlc_maximum_msat: OptionalField::Absent,
3842                         fee_base_msat: 0,
3843                         fee_proportional_millionths: 0,
3844                         excess_data: Vec::new()
3845                 });
3846
3847                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
3848                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3849                         short_channel_id: 6,
3850                         timestamp: 2,
3851                         flags: 0,
3852                         cltv_expiry_delta: 0,
3853                         htlc_minimum_msat: 0,
3854                         htlc_maximum_msat: OptionalField::Absent,
3855                         fee_base_msat: 150_000,
3856                         fee_proportional_millionths: 0,
3857                         excess_data: Vec::new()
3858                 });
3859                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
3860                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3861                         short_channel_id: 11,
3862                         timestamp: 2,
3863                         flags: 0,
3864                         cltv_expiry_delta: 0,
3865                         htlc_minimum_msat: 0,
3866                         htlc_maximum_msat: OptionalField::Absent,
3867                         fee_base_msat: 0,
3868                         fee_proportional_millionths: 0,
3869                         excess_data: Vec::new()
3870                 });
3871
3872                 {
3873                         // Attempt to route more than available results in a failure.
3874                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3875                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 210_000, 42, Arc::clone(&logger), &scorer) {
3876                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3877                         } else { panic!(); }
3878                 }
3879
3880                 {
3881                         // Now, attempt to route 200 sats (exact amount we can route).
3882                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[3],
3883                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 200_000, 42, Arc::clone(&logger), &scorer).unwrap();
3884                         assert_eq!(route.paths.len(), 2);
3885
3886                         let mut total_amount_paid_msat = 0;
3887                         for path in &route.paths {
3888                                 assert_eq!(path.last().unwrap().pubkey, nodes[3]);
3889                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
3890                         }
3891                         assert_eq!(total_amount_paid_msat, 200_000);
3892                         assert_eq!(route.get_total_fees(), 150_000);
3893                 }
3894
3895         }
3896
3897         #[test]
3898         fn drop_lowest_channel_mpp_route_test() {
3899                 // This test checks that low-capacity channel is dropped when after
3900                 // path finding we realize that we found more capacity than we need.
3901                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
3902                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
3903                 let scorer = Scorer::new(0);
3904
3905                 // We need a route consisting of 3 paths:
3906                 // From our node to node2 via node0, node7, node1 (three paths one hop each).
3907
3908                 // The first and the second paths should be sufficient, but the third should be
3909                 // cheaper, so that we select it but drop later.
3910
3911                 // First, we set limits on these (previously unlimited) channels.
3912                 // Their aggregate capacity will be 50 + 60 + 20 = 130 sats.
3913
3914                 // Path via node0 is channels {1, 3}. Limit them to 100 and 50 sats (total limit 50);
3915                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3916                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3917                         short_channel_id: 1,
3918                         timestamp: 2,
3919                         flags: 0,
3920                         cltv_expiry_delta: 0,
3921                         htlc_minimum_msat: 0,
3922                         htlc_maximum_msat: OptionalField::Present(100_000),
3923                         fee_base_msat: 0,
3924                         fee_proportional_millionths: 0,
3925                         excess_data: Vec::new()
3926                 });
3927                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[0], UnsignedChannelUpdate {
3928                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3929                         short_channel_id: 3,
3930                         timestamp: 2,
3931                         flags: 0,
3932                         cltv_expiry_delta: 0,
3933                         htlc_minimum_msat: 0,
3934                         htlc_maximum_msat: OptionalField::Present(50_000),
3935                         fee_base_msat: 100,
3936                         fee_proportional_millionths: 0,
3937                         excess_data: Vec::new()
3938                 });
3939
3940                 // Path via node7 is channels {12, 13}. Limit them to 60 and 60 sats (total limit 60);
3941                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3942                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3943                         short_channel_id: 12,
3944                         timestamp: 2,
3945                         flags: 0,
3946                         cltv_expiry_delta: 0,
3947                         htlc_minimum_msat: 0,
3948                         htlc_maximum_msat: OptionalField::Present(60_000),
3949                         fee_base_msat: 100,
3950                         fee_proportional_millionths: 0,
3951                         excess_data: Vec::new()
3952                 });
3953                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[7], UnsignedChannelUpdate {
3954                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3955                         short_channel_id: 13,
3956                         timestamp: 2,
3957                         flags: 0,
3958                         cltv_expiry_delta: 0,
3959                         htlc_minimum_msat: 0,
3960                         htlc_maximum_msat: OptionalField::Present(60_000),
3961                         fee_base_msat: 0,
3962                         fee_proportional_millionths: 0,
3963                         excess_data: Vec::new()
3964                 });
3965
3966                 // Path via node1 is channels {2, 4}. Limit them to 20 and 20 sats (total capacity 20 sats).
3967                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
3968                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3969                         short_channel_id: 2,
3970                         timestamp: 2,
3971                         flags: 0,
3972                         cltv_expiry_delta: 0,
3973                         htlc_minimum_msat: 0,
3974                         htlc_maximum_msat: OptionalField::Present(20_000),
3975                         fee_base_msat: 0,
3976                         fee_proportional_millionths: 0,
3977                         excess_data: Vec::new()
3978                 });
3979                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
3980                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
3981                         short_channel_id: 4,
3982                         timestamp: 2,
3983                         flags: 0,
3984                         cltv_expiry_delta: 0,
3985                         htlc_minimum_msat: 0,
3986                         htlc_maximum_msat: OptionalField::Present(20_000),
3987                         fee_base_msat: 0,
3988                         fee_proportional_millionths: 0,
3989                         excess_data: Vec::new()
3990                 });
3991
3992                 {
3993                         // Attempt to route more than available results in a failure.
3994                         if let Err(LightningError{err, action: ErrorAction::IgnoreError}) = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
3995                                         Some(InvoiceFeatures::known()), None, &Vec::new(), 150_000, 42, Arc::clone(&logger), &scorer) {
3996                                 assert_eq!(err, "Failed to find a sufficient route to the given destination");
3997                         } else { panic!(); }
3998                 }
3999
4000                 {
4001                         // Now, attempt to route 125 sats (just a bit below the capacity of 3 channels).
4002                         // Our algorithm should provide us with these 3 paths.
4003                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
4004                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 125_000, 42, Arc::clone(&logger), &scorer).unwrap();
4005                         assert_eq!(route.paths.len(), 3);
4006                         let mut total_amount_paid_msat = 0;
4007                         for path in &route.paths {
4008                                 assert_eq!(path.len(), 2);
4009                                 assert_eq!(path.last().unwrap().pubkey, nodes[2]);
4010                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
4011                         }
4012                         assert_eq!(total_amount_paid_msat, 125_000);
4013                 }
4014
4015                 {
4016                         // Attempt to route without the last small cheap channel
4017                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2],
4018                                 Some(InvoiceFeatures::known()), None, &Vec::new(), 90_000, 42, Arc::clone(&logger), &scorer).unwrap();
4019                         assert_eq!(route.paths.len(), 2);
4020                         let mut total_amount_paid_msat = 0;
4021                         for path in &route.paths {
4022                                 assert_eq!(path.len(), 2);
4023                                 assert_eq!(path.last().unwrap().pubkey, nodes[2]);
4024                                 total_amount_paid_msat += path.last().unwrap().fee_msat;
4025                         }
4026                         assert_eq!(total_amount_paid_msat, 90_000);
4027                 }
4028         }
4029
4030         #[test]
4031         fn min_criteria_consistency() {
4032                 // Test that we don't use an inconsistent metric between updating and walking nodes during
4033                 // our Dijkstra's pass. In the initial version of MPP, the "best source" for a given node
4034                 // was updated with a different criterion from the heap sorting, resulting in loops in
4035                 // calculated paths. We test for that specific case here.
4036
4037                 // We construct a network that looks like this:
4038                 //
4039                 //            node2 -1(3)2- node3
4040                 //              2          2
4041                 //               (2)     (4)
4042                 //                  1   1
4043                 //    node1 -1(5)2- node4 -1(1)2- node6
4044                 //    2
4045                 //   (6)
4046                 //        1
4047                 // our_node
4048                 //
4049                 // We create a loop on the side of our real path - our destination is node 6, with a
4050                 // previous hop of node 4. From 4, the cheapest previous path is channel 2 from node 2,
4051                 // followed by node 3 over channel 3. Thereafter, the cheapest next-hop is back to node 4
4052                 // (this time over channel 4). Channel 4 has 0 htlc_minimum_msat whereas channel 1 (the
4053                 // other channel with a previous-hop of node 4) has a high (but irrelevant to the overall
4054                 // payment) htlc_minimum_msat. In the original algorithm, this resulted in node4's
4055                 // "previous hop" being set to node 3, creating a loop in the path.
4056                 let secp_ctx = Secp256k1::new();
4057                 let logger = Arc::new(test_utils::TestLogger::new());
4058                 let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
4059                 let net_graph_msg_handler = NetGraphMsgHandler::new(network_graph, None, Arc::clone(&logger));
4060                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
4061                 let scorer = Scorer::new(0);
4062
4063                 add_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, &privkeys[1], ChannelFeatures::from_le_bytes(id_to_feature_flags(6)), 6);
4064                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
4065                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4066                         short_channel_id: 6,
4067                         timestamp: 1,
4068                         flags: 0,
4069                         cltv_expiry_delta: (6 << 8) | 0,
4070                         htlc_minimum_msat: 0,
4071                         htlc_maximum_msat: OptionalField::Absent,
4072                         fee_base_msat: 0,
4073                         fee_proportional_millionths: 0,
4074                         excess_data: Vec::new()
4075                 });
4076                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[1], NodeFeatures::from_le_bytes(id_to_feature_flags(1)), 0);
4077
4078                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(5)), 5);
4079                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
4080                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4081                         short_channel_id: 5,
4082                         timestamp: 1,
4083                         flags: 0,
4084                         cltv_expiry_delta: (5 << 8) | 0,
4085                         htlc_minimum_msat: 0,
4086                         htlc_maximum_msat: OptionalField::Absent,
4087                         fee_base_msat: 100,
4088                         fee_proportional_millionths: 0,
4089                         excess_data: Vec::new()
4090                 });
4091                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[4], NodeFeatures::from_le_bytes(id_to_feature_flags(4)), 0);
4092
4093                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[3], ChannelFeatures::from_le_bytes(id_to_feature_flags(4)), 4);
4094                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
4095                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4096                         short_channel_id: 4,
4097                         timestamp: 1,
4098                         flags: 0,
4099                         cltv_expiry_delta: (4 << 8) | 0,
4100                         htlc_minimum_msat: 0,
4101                         htlc_maximum_msat: OptionalField::Absent,
4102                         fee_base_msat: 0,
4103                         fee_proportional_millionths: 0,
4104                         excess_data: Vec::new()
4105                 });
4106                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[3], NodeFeatures::from_le_bytes(id_to_feature_flags(3)), 0);
4107
4108                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], &privkeys[2], ChannelFeatures::from_le_bytes(id_to_feature_flags(3)), 3);
4109                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[3], UnsignedChannelUpdate {
4110                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4111                         short_channel_id: 3,
4112                         timestamp: 1,
4113                         flags: 0,
4114                         cltv_expiry_delta: (3 << 8) | 0,
4115                         htlc_minimum_msat: 0,
4116                         htlc_maximum_msat: OptionalField::Absent,
4117                         fee_base_msat: 0,
4118                         fee_proportional_millionths: 0,
4119                         excess_data: Vec::new()
4120                 });
4121                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[2], NodeFeatures::from_le_bytes(id_to_feature_flags(2)), 0);
4122
4123                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], &privkeys[4], ChannelFeatures::from_le_bytes(id_to_feature_flags(2)), 2);
4124                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[2], UnsignedChannelUpdate {
4125                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4126                         short_channel_id: 2,
4127                         timestamp: 1,
4128                         flags: 0,
4129                         cltv_expiry_delta: (2 << 8) | 0,
4130                         htlc_minimum_msat: 0,
4131                         htlc_maximum_msat: OptionalField::Absent,
4132                         fee_base_msat: 0,
4133                         fee_proportional_millionths: 0,
4134                         excess_data: Vec::new()
4135                 });
4136
4137                 add_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], &privkeys[6], ChannelFeatures::from_le_bytes(id_to_feature_flags(1)), 1);
4138                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[4], UnsignedChannelUpdate {
4139                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4140                         short_channel_id: 1,
4141                         timestamp: 1,
4142                         flags: 0,
4143                         cltv_expiry_delta: (1 << 8) | 0,
4144                         htlc_minimum_msat: 100,
4145                         htlc_maximum_msat: OptionalField::Absent,
4146                         fee_base_msat: 0,
4147                         fee_proportional_millionths: 0,
4148                         excess_data: Vec::new()
4149                 });
4150                 add_or_update_node(&net_graph_msg_handler, &secp_ctx, &privkeys[6], NodeFeatures::from_le_bytes(id_to_feature_flags(6)), 0);
4151
4152                 {
4153                         // Now ensure the route flows simply over nodes 1 and 4 to 6.
4154                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &Vec::new(), 10_000, 42, Arc::clone(&logger), &scorer).unwrap();
4155                         assert_eq!(route.paths.len(), 1);
4156                         assert_eq!(route.paths[0].len(), 3);
4157
4158                         assert_eq!(route.paths[0][0].pubkey, nodes[1]);
4159                         assert_eq!(route.paths[0][0].short_channel_id, 6);
4160                         assert_eq!(route.paths[0][0].fee_msat, 100);
4161                         assert_eq!(route.paths[0][0].cltv_expiry_delta, (5 << 8) | 0);
4162                         assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(1));
4163                         assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(6));
4164
4165                         assert_eq!(route.paths[0][1].pubkey, nodes[4]);
4166                         assert_eq!(route.paths[0][1].short_channel_id, 5);
4167                         assert_eq!(route.paths[0][1].fee_msat, 0);
4168                         assert_eq!(route.paths[0][1].cltv_expiry_delta, (1 << 8) | 0);
4169                         assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(4));
4170                         assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(5));
4171
4172                         assert_eq!(route.paths[0][2].pubkey, nodes[6]);
4173                         assert_eq!(route.paths[0][2].short_channel_id, 1);
4174                         assert_eq!(route.paths[0][2].fee_msat, 10_000);
4175                         assert_eq!(route.paths[0][2].cltv_expiry_delta, 42);
4176                         assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(6));
4177                         assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(1));
4178                 }
4179         }
4180
4181
4182         #[test]
4183         fn exact_fee_liquidity_limit() {
4184                 // Test that if, while walking the graph, we find a hop that has exactly enough liquidity
4185                 // for us, including later hop fees, we take it. In the first version of our MPP algorithm
4186                 // we calculated fees on a higher value, resulting in us ignoring such paths.
4187                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
4188                 let (our_privkey, our_id, _, nodes) = get_nodes(&secp_ctx);
4189                 let scorer = Scorer::new(0);
4190
4191                 // We modify the graph to set the htlc_maximum of channel 2 to below the value we wish to
4192                 // send.
4193                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
4194                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4195                         short_channel_id: 2,
4196                         timestamp: 2,
4197                         flags: 0,
4198                         cltv_expiry_delta: 0,
4199                         htlc_minimum_msat: 0,
4200                         htlc_maximum_msat: OptionalField::Present(85_000),
4201                         fee_base_msat: 0,
4202                         fee_proportional_millionths: 0,
4203                         excess_data: Vec::new()
4204                 });
4205
4206                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
4207                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4208                         short_channel_id: 12,
4209                         timestamp: 2,
4210                         flags: 0,
4211                         cltv_expiry_delta: (4 << 8) | 1,
4212                         htlc_minimum_msat: 0,
4213                         htlc_maximum_msat: OptionalField::Present(270_000),
4214                         fee_base_msat: 0,
4215                         fee_proportional_millionths: 1000000,
4216                         excess_data: Vec::new()
4217                 });
4218
4219                 {
4220                         // Now, attempt to route 90 sats, which is exactly 90 sats at the last hop, plus the
4221                         // 200% fee charged channel 13 in the 1-to-2 direction.
4222                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], None, None, &Vec::new(), 90_000, 42, Arc::clone(&logger), &scorer).unwrap();
4223                         assert_eq!(route.paths.len(), 1);
4224                         assert_eq!(route.paths[0].len(), 2);
4225
4226                         assert_eq!(route.paths[0][0].pubkey, nodes[7]);
4227                         assert_eq!(route.paths[0][0].short_channel_id, 12);
4228                         assert_eq!(route.paths[0][0].fee_msat, 90_000*2);
4229                         assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
4230                         assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8));
4231                         assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12));
4232
4233                         assert_eq!(route.paths[0][1].pubkey, nodes[2]);
4234                         assert_eq!(route.paths[0][1].short_channel_id, 13);
4235                         assert_eq!(route.paths[0][1].fee_msat, 90_000);
4236                         assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
4237                         assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
4238                         assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
4239                 }
4240         }
4241
4242         #[test]
4243         fn htlc_max_reduction_below_min() {
4244                 // Test that if, while walking the graph, we reduce the value being sent to meet an
4245                 // htlc_maximum_msat, we don't end up undershooting a later htlc_minimum_msat. In the
4246                 // initial version of MPP we'd accept such routes but reject them while recalculating fees,
4247                 // resulting in us thinking there is no possible path, even if other paths exist.
4248                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
4249                 let (our_privkey, our_id, privkeys, nodes) = get_nodes(&secp_ctx);
4250                 let scorer = Scorer::new(0);
4251
4252                 // We modify the graph to set the htlc_minimum of channel 2 and 4 as needed - channel 2
4253                 // gets an htlc_maximum_msat of 80_000 and channel 4 an htlc_minimum_msat of 90_000. We
4254                 // then try to send 90_000.
4255                 update_channel(&net_graph_msg_handler, &secp_ctx, &our_privkey, UnsignedChannelUpdate {
4256                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4257                         short_channel_id: 2,
4258                         timestamp: 2,
4259                         flags: 0,
4260                         cltv_expiry_delta: 0,
4261                         htlc_minimum_msat: 0,
4262                         htlc_maximum_msat: OptionalField::Present(80_000),
4263                         fee_base_msat: 0,
4264                         fee_proportional_millionths: 0,
4265                         excess_data: Vec::new()
4266                 });
4267                 update_channel(&net_graph_msg_handler, &secp_ctx, &privkeys[1], UnsignedChannelUpdate {
4268                         chain_hash: genesis_block(Network::Testnet).header.block_hash(),
4269                         short_channel_id: 4,
4270                         timestamp: 2,
4271                         flags: 0,
4272                         cltv_expiry_delta: (4 << 8) | 1,
4273                         htlc_minimum_msat: 90_000,
4274                         htlc_maximum_msat: OptionalField::Absent,
4275                         fee_base_msat: 0,
4276                         fee_proportional_millionths: 0,
4277                         excess_data: Vec::new()
4278                 });
4279
4280                 {
4281                         // Now, attempt to route 90 sats, hitting the htlc_minimum on channel 4, but
4282                         // overshooting the htlc_maximum on channel 2. Thus, we should pick the (absurdly
4283                         // expensive) channels 12-13 path.
4284                         let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[2], Some(InvoiceFeatures::known()), None, &Vec::new(), 90_000, 42, Arc::clone(&logger), &scorer).unwrap();
4285                         assert_eq!(route.paths.len(), 1);
4286                         assert_eq!(route.paths[0].len(), 2);
4287
4288                         assert_eq!(route.paths[0][0].pubkey, nodes[7]);
4289                         assert_eq!(route.paths[0][0].short_channel_id, 12);
4290                         assert_eq!(route.paths[0][0].fee_msat, 90_000*2);
4291                         assert_eq!(route.paths[0][0].cltv_expiry_delta, (13 << 8) | 1);
4292                         assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(8));
4293                         assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(12));
4294
4295                         assert_eq!(route.paths[0][1].pubkey, nodes[2]);
4296                         assert_eq!(route.paths[0][1].short_channel_id, 13);
4297                         assert_eq!(route.paths[0][1].fee_msat, 90_000);
4298                         assert_eq!(route.paths[0][1].cltv_expiry_delta, 42);
4299                         assert_eq!(route.paths[0][1].node_features.le_flags(), InvoiceFeatures::known().le_flags());
4300                         assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(13));
4301                 }
4302         }
4303
4304         #[test]
4305         fn multiple_direct_first_hops() {
4306                 // Previously we'd only ever considered one first hop path per counterparty.
4307                 // However, as we don't restrict users to one channel per peer, we really need to support
4308                 // looking at all first hop paths.
4309                 // Here we test that we do not ignore all-but-the-last first hop paths per counterparty (as
4310                 // we used to do by overwriting the `first_hop_targets` hashmap entry) and that we can MPP
4311                 // route over multiple channels with the same first hop.
4312                 let secp_ctx = Secp256k1::new();
4313                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
4314                 let logger = Arc::new(test_utils::TestLogger::new());
4315                 let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
4316                 let scorer = Scorer::new(0);
4317
4318                 {
4319                         let route = get_route(&our_id, &network_graph, &nodes[0], Some(InvoiceFeatures::known()), Some(&[
4320                                 &get_channel_details(Some(3), nodes[0], InitFeatures::known(), 200_000),
4321                                 &get_channel_details(Some(2), nodes[0], InitFeatures::known(), 10_000),
4322                         ]), &[], 100_000, 42, Arc::clone(&logger), &scorer).unwrap();
4323                         assert_eq!(route.paths.len(), 1);
4324                         assert_eq!(route.paths[0].len(), 1);
4325
4326                         assert_eq!(route.paths[0][0].pubkey, nodes[0]);
4327                         assert_eq!(route.paths[0][0].short_channel_id, 3);
4328                         assert_eq!(route.paths[0][0].fee_msat, 100_000);
4329                 }
4330                 {
4331                         let route = get_route(&our_id, &network_graph, &nodes[0], Some(InvoiceFeatures::known()), Some(&[
4332                                 &get_channel_details(Some(3), nodes[0], InitFeatures::known(), 50_000),
4333                                 &get_channel_details(Some(2), nodes[0], InitFeatures::known(), 50_000),
4334                         ]), &[], 100_000, 42, Arc::clone(&logger), &scorer).unwrap();
4335                         assert_eq!(route.paths.len(), 2);
4336                         assert_eq!(route.paths[0].len(), 1);
4337                         assert_eq!(route.paths[1].len(), 1);
4338
4339                         assert_eq!(route.paths[0][0].pubkey, nodes[0]);
4340                         assert_eq!(route.paths[0][0].short_channel_id, 3);
4341                         assert_eq!(route.paths[0][0].fee_msat, 50_000);
4342
4343                         assert_eq!(route.paths[1][0].pubkey, nodes[0]);
4344                         assert_eq!(route.paths[1][0].short_channel_id, 2);
4345                         assert_eq!(route.paths[1][0].fee_msat, 50_000);
4346                 }
4347         }
4348
4349         #[test]
4350         fn prefers_shorter_route_with_higher_fees() {
4351                 let (secp_ctx, net_graph_msg_handler, _, logger) = build_graph();
4352                 let (_, our_id, _, nodes) = get_nodes(&secp_ctx);
4353
4354                 // Applying a 100 msat penalty to each hop results in taking channels 7 and 10 to nodes[6]
4355                 // from nodes[2] rather than channel 6, 11, and 8, even though the longer path is cheaper.
4356                 let scorer = Scorer::new(100);
4357                 let route = get_route(&our_id, &net_graph_msg_handler.network_graph, &nodes[6], None, None, &last_hops(&nodes).iter().collect::<Vec<_>>(), 100, 42, Arc::clone(&logger), &scorer).unwrap();
4358                 assert_eq!(route.paths[0].len(), 4);
4359
4360                 assert_eq!(route.paths[0][0].pubkey, nodes[1]);
4361                 assert_eq!(route.paths[0][0].short_channel_id, 2);
4362                 assert_eq!(route.paths[0][0].fee_msat, 200);
4363                 assert_eq!(route.paths[0][0].cltv_expiry_delta, (4 << 8) | 1);
4364                 assert_eq!(route.paths[0][0].node_features.le_flags(), &id_to_feature_flags(2));
4365                 assert_eq!(route.paths[0][0].channel_features.le_flags(), &id_to_feature_flags(2));
4366
4367                 assert_eq!(route.paths[0][1].pubkey, nodes[2]);
4368                 assert_eq!(route.paths[0][1].short_channel_id, 4);
4369                 assert_eq!(route.paths[0][1].fee_msat, 100);
4370                 assert_eq!(route.paths[0][1].cltv_expiry_delta, (7 << 8) | 1);
4371                 assert_eq!(route.paths[0][1].node_features.le_flags(), &id_to_feature_flags(3));
4372                 assert_eq!(route.paths[0][1].channel_features.le_flags(), &id_to_feature_flags(4));
4373
4374                 assert_eq!(route.paths[0][2].pubkey, nodes[5]);
4375                 assert_eq!(route.paths[0][2].short_channel_id, 7);
4376                 assert_eq!(route.paths[0][2].fee_msat, 0);
4377                 assert_eq!(route.paths[0][2].cltv_expiry_delta, (10 << 8) | 1);
4378                 assert_eq!(route.paths[0][2].node_features.le_flags(), &id_to_feature_flags(6));
4379                 assert_eq!(route.paths[0][2].channel_features.le_flags(), &id_to_feature_flags(7));
4380
4381                 assert_eq!(route.paths[0][3].pubkey, nodes[6]);
4382                 assert_eq!(route.paths[0][3].short_channel_id, 10);
4383                 assert_eq!(route.paths[0][3].fee_msat, 100);
4384                 assert_eq!(route.paths[0][3].cltv_expiry_delta, 42);
4385                 assert_eq!(route.paths[0][3].node_features.le_flags(), &Vec::<u8>::new()); // We don't pass flags in from invoices yet
4386                 assert_eq!(route.paths[0][3].channel_features.le_flags(), &Vec::<u8>::new()); // We can't learn any flags from invoices, sadly
4387
4388                 assert_eq!(route.get_total_fees(), 300);
4389                 assert_eq!(route.get_total_amount(), 100);
4390         }
4391
4392         #[test]
4393         fn total_fees_single_path() {
4394                 let route = Route {
4395                         paths: vec![vec![
4396                                 RouteHop {
4397                                         pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
4398                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4399                                         short_channel_id: 0, fee_msat: 100, cltv_expiry_delta: 0
4400                                 },
4401                                 RouteHop {
4402                                         pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
4403                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4404                                         short_channel_id: 0, fee_msat: 150, cltv_expiry_delta: 0
4405                                 },
4406                                 RouteHop {
4407                                         pubkey: PublicKey::from_slice(&hex::decode("027f31ebc5462c1fdce1b737ecff52d37d75dea43ce11c74d25aa297165faa2007").unwrap()[..]).unwrap(),
4408                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4409                                         short_channel_id: 0, fee_msat: 225, cltv_expiry_delta: 0
4410                                 },
4411                         ]],
4412                 };
4413
4414                 assert_eq!(route.get_total_fees(), 250);
4415                 assert_eq!(route.get_total_amount(), 225);
4416         }
4417
4418         #[test]
4419         fn total_fees_multi_path() {
4420                 let route = Route {
4421                         paths: vec![vec![
4422                                 RouteHop {
4423                                         pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
4424                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4425                                         short_channel_id: 0, fee_msat: 100, cltv_expiry_delta: 0
4426                                 },
4427                                 RouteHop {
4428                                         pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
4429                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4430                                         short_channel_id: 0, fee_msat: 150, cltv_expiry_delta: 0
4431                                 },
4432                         ],vec![
4433                                 RouteHop {
4434                                         pubkey: PublicKey::from_slice(&hex::decode("02eec7245d6b7d2ccb30380bfbe2a3648cd7a942653f5aa340edcea1f283686619").unwrap()[..]).unwrap(),
4435                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4436                                         short_channel_id: 0, fee_msat: 100, cltv_expiry_delta: 0
4437                                 },
4438                                 RouteHop {
4439                                         pubkey: PublicKey::from_slice(&hex::decode("0324653eac434488002cc06bbfb7f10fe18991e35f9fe4302dbea6d2353dc0ab1c").unwrap()[..]).unwrap(),
4440                                         channel_features: ChannelFeatures::empty(), node_features: NodeFeatures::empty(),
4441                                         short_channel_id: 0, fee_msat: 150, cltv_expiry_delta: 0
4442                                 },
4443                         ]],
4444                 };
4445
4446                 assert_eq!(route.get_total_fees(), 200);
4447                 assert_eq!(route.get_total_amount(), 300);
4448         }
4449
4450         #[test]
4451         fn total_empty_route_no_panic() {
4452                 // In an earlier version of `Route::get_total_fees` and `Route::get_total_amount`, they
4453                 // would both panic if the route was completely empty. We test to ensure they return 0
4454                 // here, even though its somewhat nonsensical as a route.
4455                 let route = Route { paths: Vec::new() };
4456
4457                 assert_eq!(route.get_total_fees(), 0);
4458                 assert_eq!(route.get_total_amount(), 0);
4459         }
4460
4461         #[cfg(not(feature = "no-std"))]
4462         pub(super) fn random_init_seed() -> u64 {
4463                 // Because the default HashMap in std pulls OS randomness, we can use it as a (bad) RNG.
4464                 use core::hash::{BuildHasher, Hasher};
4465                 let seed = std::collections::hash_map::RandomState::new().build_hasher().finish();
4466                 println!("Using seed of {}", seed);
4467                 seed
4468         }
4469         #[cfg(not(feature = "no-std"))]
4470         use util::ser::Readable;
4471
4472         #[test]
4473         #[cfg(not(feature = "no-std"))]
4474         fn generate_routes() {
4475                 let mut d = match super::test_utils::get_route_file() {
4476                         Ok(f) => f,
4477                         Err(e) => {
4478                                 eprintln!("{}", e);
4479                                 return;
4480                         },
4481                 };
4482                 let graph = NetworkGraph::read(&mut d).unwrap();
4483                 let scorer = Scorer::new(0);
4484
4485                 // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
4486                 let mut seed = random_init_seed() as usize;
4487                 let nodes = graph.read_only().nodes().clone();
4488                 'load_endpoints: for _ in 0..10 {
4489                         loop {
4490                                 seed = seed.overflowing_mul(0xdeadbeef).0;
4491                                 let src = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4492                                 seed = seed.overflowing_mul(0xdeadbeef).0;
4493                                 let dst = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4494                                 let amt = seed as u64 % 200_000_000;
4495                                 if get_route(src, &graph, dst, None, None, &[], amt, 42, &test_utils::TestLogger::new(), &scorer).is_ok() {
4496                                         continue 'load_endpoints;
4497                                 }
4498                         }
4499                 }
4500         }
4501
4502         #[test]
4503         #[cfg(not(feature = "no-std"))]
4504         fn generate_routes_mpp() {
4505                 let mut d = match super::test_utils::get_route_file() {
4506                         Ok(f) => f,
4507                         Err(e) => {
4508                                 eprintln!("{}", e);
4509                                 return;
4510                         },
4511                 };
4512                 let graph = NetworkGraph::read(&mut d).unwrap();
4513                 let scorer = Scorer::new(0);
4514
4515                 // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
4516                 let mut seed = random_init_seed() as usize;
4517                 let nodes = graph.read_only().nodes().clone();
4518                 'load_endpoints: for _ in 0..10 {
4519                         loop {
4520                                 seed = seed.overflowing_mul(0xdeadbeef).0;
4521                                 let src = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4522                                 seed = seed.overflowing_mul(0xdeadbeef).0;
4523                                 let dst = &PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4524                                 let amt = seed as u64 % 200_000_000;
4525                                 if get_route(src, &graph, dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &test_utils::TestLogger::new(), &scorer).is_ok() {
4526                                         continue 'load_endpoints;
4527                                 }
4528                         }
4529                 }
4530         }
4531 }
4532
4533 #[cfg(all(test, not(feature = "no-std")))]
4534 pub(crate) mod test_utils {
4535         use std::fs::File;
4536         /// Tries to open a network graph file, or panics with a URL to fetch it.
4537         pub(crate) fn get_route_file() -> Result<std::fs::File, &'static str> {
4538                 let res = File::open("net_graph-2021-05-31.bin") // By default we're run in RL/lightning
4539                         .or_else(|_| File::open("lightning/net_graph-2021-05-31.bin")) // We may be run manually in RL/
4540                         .or_else(|_| { // Fall back to guessing based on the binary location
4541                                 // path is likely something like .../rust-lightning/target/debug/deps/lightning-...
4542                                 let mut path = std::env::current_exe().unwrap();
4543                                 path.pop(); // lightning-...
4544                                 path.pop(); // deps
4545                                 path.pop(); // debug
4546                                 path.pop(); // target
4547                                 path.push("lightning");
4548                                 path.push("net_graph-2021-05-31.bin");
4549                                 eprintln!("{}", path.to_str().unwrap());
4550                                 File::open(path)
4551                         })
4552                 .map_err(|_| "Please fetch https://bitcoin.ninja/ldk-net_graph-v0.0.15-2021-05-31.bin and place it at lightning/net_graph-2021-05-31.bin");
4553                 #[cfg(require_route_graph_test)]
4554                 return Ok(res.unwrap());
4555                 #[cfg(not(require_route_graph_test))]
4556                 return res;
4557         }
4558 }
4559
4560 #[cfg(all(test, feature = "unstable", not(feature = "no-std")))]
4561 mod benches {
4562         use super::*;
4563         use routing::scorer::Scorer;
4564         use util::logger::{Logger, Record};
4565
4566         use test::Bencher;
4567
4568         struct DummyLogger {}
4569         impl Logger for DummyLogger {
4570                 fn log(&self, _record: &Record) {}
4571         }
4572
4573         #[bench]
4574         fn generate_routes(bench: &mut Bencher) {
4575                 let mut d = test_utils::get_route_file().unwrap();
4576                 let graph = NetworkGraph::read(&mut d).unwrap();
4577                 let nodes = graph.read_only().nodes().clone();
4578                 let scorer = Scorer::new(0);
4579
4580                 // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
4581                 let mut path_endpoints = Vec::new();
4582                 let mut seed: usize = 0xdeadbeef;
4583                 'load_endpoints: for _ in 0..100 {
4584                         loop {
4585                                 seed *= 0xdeadbeef;
4586                                 let src = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4587                                 seed *= 0xdeadbeef;
4588                                 let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4589                                 let amt = seed as u64 % 1_000_000;
4590                                 if get_route(&src, &graph, &dst, None, None, &[], amt, 42, &DummyLogger{}, &scorer).is_ok() {
4591                                         path_endpoints.push((src, dst, amt));
4592                                         continue 'load_endpoints;
4593                                 }
4594                         }
4595                 }
4596
4597                 // ...then benchmark finding paths between the nodes we learned.
4598                 let mut idx = 0;
4599                 bench.iter(|| {
4600                         let (src, dst, amt) = path_endpoints[idx % path_endpoints.len()];
4601                         assert!(get_route(&src, &graph, &dst, None, None, &[], amt, 42, &DummyLogger{}, &scorer).is_ok());
4602                         idx += 1;
4603                 });
4604         }
4605
4606         #[bench]
4607         fn generate_mpp_routes(bench: &mut Bencher) {
4608                 let mut d = test_utils::get_route_file().unwrap();
4609                 let graph = NetworkGraph::read(&mut d).unwrap();
4610                 let nodes = graph.read_only().nodes().clone();
4611                 let scorer = Scorer::new(0);
4612
4613                 // First, get 100 (source, destination) pairs for which route-getting actually succeeds...
4614                 let mut path_endpoints = Vec::new();
4615                 let mut seed: usize = 0xdeadbeef;
4616                 'load_endpoints: for _ in 0..100 {
4617                         loop {
4618                                 seed *= 0xdeadbeef;
4619                                 let src = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4620                                 seed *= 0xdeadbeef;
4621                                 let dst = PublicKey::from_slice(nodes.keys().skip(seed % nodes.len()).next().unwrap().as_slice()).unwrap();
4622                                 let amt = seed as u64 % 1_000_000;
4623                                 if get_route(&src, &graph, &dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}, &scorer).is_ok() {
4624                                         path_endpoints.push((src, dst, amt));
4625                                         continue 'load_endpoints;
4626                                 }
4627                         }
4628                 }
4629
4630                 // ...then benchmark finding paths between the nodes we learned.
4631                 let mut idx = 0;
4632                 bench.iter(|| {
4633                         let (src, dst, amt) = path_endpoints[idx % path_endpoints.len()];
4634                         assert!(get_route(&src, &graph, &dst, Some(InvoiceFeatures::known()), None, &[], amt, 42, &DummyLogger{}, &scorer).is_ok());
4635                         idx += 1;
4636                 });
4637         }
4638 }