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

   1 use secp256k1::key::PublicKey;
   2 use secp256k1::{Secp256k1,Message};
   3
   4 use bitcoin::util::hash::Sha256dHash;
   5
   6 use ln::channelmanager;
   7 use ln::msgs::{ErrorAction,HandleError,RoutingMessageHandler,MsgEncodable,NetAddress,GlobalFeatures};
   8 use ln::msgs;
   9
  10 use std::cmp;
  11 use std::sync::RwLock;
  12 use std::collections::{HashMap,BinaryHeap};
  13 use std::collections::hash_map::Entry;
  14
  15 /// A hop in a route
  16 #[derive(Clone)]
  17 pub struct RouteHop {
  18         pub pubkey: PublicKey,
  19         /// The channel that should be used from the previous hop to reach this node.
  20         pub short_channel_id: u64,
  21         /// The fee taken on this hop. For the last hop, this should be the full value of the payment.
  22         pub fee_msat: u64,
  23         /// The CLTV delta added for this hop. For the last hop, this should be the full CLTV value
  24         /// expected at the destination, NOT a delta.
  25         pub cltv_expiry_delta: u32,
  26 }
  27
  28 /// A route from us through the network to a destination
  29 #[derive(Clone)]
  30 pub struct Route {
  31         /// The list of hops, NOT INCLUDING our own, where the last hop is the destination. Thus, this
  32         /// must always be at least length one. By protocol rules, this may not currently exceed 20 in
  33         /// length.
  34         pub hops: Vec<RouteHop>,
  35 }
  36
  37 struct DirectionalChannelInfo {
  38         src_node_id: PublicKey,
  39         last_update: u32,
  40         enabled: bool,
  41         cltv_expiry_delta: u16,
  42         htlc_minimum_msat: u64,
  43         fee_base_msat: u32,
  44         fee_proportional_millionths: u32,
  45 }
  46
  47 struct ChannelInfo {
  48         features: GlobalFeatures,
  49         one_to_two: DirectionalChannelInfo,
  50         two_to_one: DirectionalChannelInfo,
  51 }
  52
  53 struct NodeInfo {
  54         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
  55         channels: Vec<(u64, Sha256dHash)>,
  56         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
  57         channels: Vec<u64>,
  58
  59         lowest_inbound_channel_fee_base_msat: u32,
  60         lowest_inbound_channel_fee_proportional_millionths: u32,
  61
  62         features: GlobalFeatures,
  63         last_update: u32,
  64         rgb: [u8; 3],
  65         alias: [u8; 32],
  66         addresses: Vec<NetAddress>,
  67 }
  68
  69 struct NetworkMap {
  70         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
  71         channels: HashMap<(u64, Sha256dHash), ChannelInfo>,
  72         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
  73         channels: HashMap<u64, ChannelInfo>,
  74
  75         our_node_id: PublicKey,
  76         nodes: HashMap<PublicKey, NodeInfo>,
  77 }
  78
  79 impl NetworkMap {
  80         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
  81         #[inline]
  82         fn get_key(short_channel_id: u64, chain_hash: Sha256dHash) -> (u64, Sha256dHash) {
  83                 (short_channel_id, chain_hash)
  84         }
  85
  86         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
  87         #[inline]
  88         fn get_key(short_channel_id: u64, _: Sha256dHash) -> u64 {
  89                 short_channel_id
  90         }
  91 }
  92
  93 /// A channel descriptor which provides a last-hop route to get_route
  94 pub struct RouteHint {
  95         pub src_node_id: PublicKey,
  96         pub short_channel_id: u64,
  97         pub fee_base_msat: u64,
  98         pub fee_proportional_millionths: u32,
  99         pub cltv_expiry_delta: u16,
 100         pub htlc_minimum_msat: u64,
 101 }
 102
 103 /// Tracks a view of the network, receiving updates from peers and generating Routes to
 104 /// payment destinations.
 105 pub struct Router {
 106         secp_ctx: Secp256k1,
 107         network_map: RwLock<NetworkMap>,
 108 }
 109
 110 macro_rules! secp_verify_sig {
 111         ( $secp_ctx: expr, $msg: expr, $sig: expr, $pubkey: expr ) => {
 112                 match $secp_ctx.verify($msg, $sig, $pubkey) {
 113                         Ok(_) => {},
 114                         Err(_) => return Err(HandleError{err: "Invalid signature from remote node", action: None}),
 115                 }
 116         };
 117 }
 118
 119 impl RoutingMessageHandler for Router {
 120         fn handle_node_announcement(&self, msg: &msgs::NodeAnnouncement) -> Result<(), HandleError> {
 121                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 122                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &msg.contents.node_id);
 123
 124                 let mut network = self.network_map.write().unwrap();
 125                 match network.nodes.get_mut(&msg.contents.node_id) {
 126                         None => Err(HandleError{err: "No existing channels for node_announcement", action: Some(ErrorAction::IgnoreError)}),
 127                         Some(node) => {
 128                                 if node.last_update >= msg.contents.timestamp {
 129                                         return Err(HandleError{err: "Update older than last processed update", action: Some(ErrorAction::IgnoreError)});
 130                                 }
 131
 132                                 node.features = msg.contents.features.clone();
 133                                 node.last_update = msg.contents.timestamp;
 134                                 node.rgb = msg.contents.rgb;
 135                                 node.alias = msg.contents.alias;
 136                                 node.addresses = msg.contents.addresses.clone();
 137                                 Ok(())
 138                         }
 139                 }
 140         }
 141
 142         fn handle_channel_announcement(&self, msg: &msgs::ChannelAnnouncement) -> Result<bool, HandleError> {
 143                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 144                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
 145                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
 146                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
 147                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
 148
 149                 //TODO: Call blockchain thing to ask if the short_channel_id is valid
 150                 //TODO: Only allow bitcoin chain_hash
 151
 152                 if msg.contents.features.requires_unknown_bits() {
 153                         return Err(HandleError{err: "Channel announcement required unknown feature flags", action: None});
 154                 }
 155
 156                 let mut network = self.network_map.write().unwrap();
 157
 158                 match network.channels.entry(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
 159                         Entry::Occupied(_) => {
 160                                 //TODO: because asking the blockchain if short_channel_id is valid is only optional
 161                                 //in the blockchain API, we need to handle it smartly here, though its unclear
 162                                 //exactly how...
 163                                 return Err(HandleError{err: "Already have knowledge of channel", action: Some(ErrorAction::IgnoreError)})
 164                         },
 165                         Entry::Vacant(entry) => {
 166                                 entry.insert(ChannelInfo {
 167                                         features: msg.contents.features.clone(),
 168                                         one_to_two: DirectionalChannelInfo {
 169                                                 src_node_id: msg.contents.node_id_1.clone(),
 170                                                 last_update: 0,
 171                                                 enabled: false,
 172                                                 cltv_expiry_delta: u16::max_value(),
 173                                                 htlc_minimum_msat: u64::max_value(),
 174                                                 fee_base_msat: u32::max_value(),
 175                                                 fee_proportional_millionths: u32::max_value(),
 176                                         },
 177                                         two_to_one: DirectionalChannelInfo {
 178                                                 src_node_id: msg.contents.node_id_2.clone(),
 179                                                 last_update: 0,
 180                                                 enabled: false,
 181                                                 cltv_expiry_delta: u16::max_value(),
 182                                                 htlc_minimum_msat: u64::max_value(),
 183                                                 fee_base_msat: u32::max_value(),
 184                                                 fee_proportional_millionths: u32::max_value(),
 185                                         }
 186                                 });
 187                         }
 188                 };
 189
 190                 macro_rules! add_channel_to_node {
 191                         ( $node_id: expr ) => {
 192                                 match network.nodes.entry($node_id) {
 193                                         Entry::Occupied(node_entry) => {
 194                                                 node_entry.into_mut().channels.push(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash));
 195                                         },
 196                                         Entry::Vacant(node_entry) => {
 197                                                 node_entry.insert(NodeInfo {
 198                                                         channels: vec!(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)),
 199                                                         lowest_inbound_channel_fee_base_msat: u32::max_value(),
 200                                                         lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
 201                                                         features: GlobalFeatures::new(),
 202                                                         last_update: 0,
 203                                                         rgb: [0; 3],
 204                                                         alias: [0; 32],
 205                                                         addresses: Vec::new(),
 206                                                 });
 207                                         }
 208                                 }
 209                         };
 210                 }
 211
 212                 add_channel_to_node!(msg.contents.node_id_1);
 213                 add_channel_to_node!(msg.contents.node_id_2);
 214
 215                 Ok(!msg.contents.features.supports_unknown_bits())
 216         }
 217
 218         fn handle_htlc_fail_channel_update(&self, update: &msgs::HTLCFailChannelUpdate) {
 219                 match update {
 220                         &msgs::HTLCFailChannelUpdate::ChannelUpdateMessage { ref msg } => {
 221                                 let _ = self.handle_channel_update(msg);
 222                         },
 223                         &msgs::HTLCFailChannelUpdate::ChannelClosed { ref short_channel_id } => {
 224                                 let mut network = self.network_map.write().unwrap();
 225                                 network.channels.remove(short_channel_id);
 226                         },
 227                 }
 228         }
 229
 230         fn handle_channel_update(&self, msg: &msgs::ChannelUpdate) -> Result<(), HandleError> {
 231                 let mut network = self.network_map.write().unwrap();
 232                 let dest_node_id;
 233                 let chan_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
 234                 let chan_was_enabled;
 235
 236                 match network.channels.get_mut(&NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
 237                         None => return Err(HandleError{err: "Couldn't find channel for update", action: Some(ErrorAction::IgnoreError)}),
 238                         Some(channel) => {
 239                                 macro_rules! maybe_update_channel_info {
 240                                         ( $target: expr) => {
 241                                                 if $target.last_update >= msg.contents.timestamp {
 242                                                         return Err(HandleError{err: "Update older than last processed update", action: Some(ErrorAction::IgnoreError)});
 243                                                 }
 244                                                 chan_was_enabled = $target.enabled;
 245                                                 $target.last_update = msg.contents.timestamp;
 246                                                 $target.enabled = chan_enabled;
 247                                                 $target.cltv_expiry_delta = msg.contents.cltv_expiry_delta;
 248                                                 $target.htlc_minimum_msat = msg.contents.htlc_minimum_msat;
 249                                                 $target.fee_base_msat = msg.contents.fee_base_msat;
 250                                                 $target.fee_proportional_millionths = msg.contents.fee_proportional_millionths;
 251                                         }
 252                                 }
 253
 254                                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 255                                 if msg.contents.flags & 1 == 1 {
 256                                         dest_node_id = channel.one_to_two.src_node_id.clone();
 257                                         secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.two_to_one.src_node_id);
 258                                         maybe_update_channel_info!(channel.two_to_one);
 259                                 } else {
 260                                         dest_node_id = channel.two_to_one.src_node_id.clone();
 261                                         secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.one_to_two.src_node_id);
 262                                         maybe_update_channel_info!(channel.one_to_two);
 263                                 }
 264                         }
 265                 }
 266
 267                 if chan_enabled {
 268                         let node = network.nodes.get_mut(&dest_node_id).unwrap();
 269                         node.lowest_inbound_channel_fee_base_msat = cmp::min(node.lowest_inbound_channel_fee_base_msat, msg.contents.fee_base_msat);
 270                         node.lowest_inbound_channel_fee_proportional_millionths = cmp::min(node.lowest_inbound_channel_fee_proportional_millionths, msg.contents.fee_proportional_millionths);
 271                 } else if chan_was_enabled {
 272                         let mut lowest_inbound_channel_fee_base_msat = u32::max_value();
 273                         let mut lowest_inbound_channel_fee_proportional_millionths = u32::max_value();
 274
 275                         {
 276                                 let node = network.nodes.get(&dest_node_id).unwrap();
 277
 278                                 for chan_id in node.channels.iter() {
 279                                         let chan = network.channels.get(chan_id).unwrap();
 280                                         if chan.one_to_two.src_node_id == dest_node_id {
 281                                                 lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.two_to_one.fee_base_msat);
 282                                                 lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.two_to_one.fee_proportional_millionths);
 283                                         } else {
 284                                                 lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.one_to_two.fee_base_msat);
 285                                                 lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.one_to_two.fee_proportional_millionths);
 286                                         }
 287                                 }
 288                         }
 289
 290                         //TODO: satisfy the borrow-checker without a double-map-lookup :(
 291                         let mut_node = network.nodes.get_mut(&dest_node_id).unwrap();
 292                         mut_node.lowest_inbound_channel_fee_base_msat = lowest_inbound_channel_fee_base_msat;
 293                         mut_node.lowest_inbound_channel_fee_proportional_millionths = lowest_inbound_channel_fee_proportional_millionths;
 294                 }
 295
 296                 Ok(())
 297         }
 298 }
 299
 300 #[derive(Eq, PartialEq)]
 301 struct RouteGraphNode {
 302         pubkey: PublicKey,
 303         lowest_fee_to_peer_through_node: u64,
 304 }
 305
 306 impl cmp::Ord for RouteGraphNode {
 307         fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
 308                 other.lowest_fee_to_peer_through_node.cmp(&self.lowest_fee_to_peer_through_node)
 309                         .then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize()))
 310         }
 311 }
 312
 313 impl cmp::PartialOrd for RouteGraphNode {
 314         fn partial_cmp(&self, other: &RouteGraphNode) -> Option<cmp::Ordering> {
 315                 Some(self.cmp(other))
 316         }
 317 }
 318
 319 struct DummyDirectionalChannelInfo {
 320         src_node_id: PublicKey,
 321         cltv_expiry_delta: u32,
 322         htlc_minimum_msat: u64,
 323         fee_base_msat: u32,
 324         fee_proportional_millionths: u32,
 325 }
 326
 327 impl Router {
 328         pub fn new(our_pubkey: PublicKey) -> Router {
 329                 let mut nodes = HashMap::new();
 330                 nodes.insert(our_pubkey.clone(), NodeInfo {
 331                         channels: Vec::new(),
 332                         lowest_inbound_channel_fee_base_msat: u32::max_value(),
 333                         lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
 334                         features: GlobalFeatures::new(),
 335                         last_update: 0,
 336                         rgb: [0; 3],
 337                         alias: [0; 32],
 338                         addresses: Vec::new(),
 339                 });
 340                 Router {
 341                         secp_ctx: Secp256k1::new(),
 342                         network_map: RwLock::new(NetworkMap {
 343                                 channels: HashMap::new(),
 344                                 our_node_id: our_pubkey,
 345                                 nodes: nodes,
 346                         }),
 347                 }
 348         }
 349
 350         /// Get network addresses by node id
 351         pub fn get_addresses(&self, pubkey: &PublicKey) -> Option<Vec<NetAddress>> {
 352                 let network = self.network_map.read().unwrap();
 353                 network.nodes.get(pubkey).map(|n| n.addresses.clone())
 354         }
 355
 356         /// Marks a node as having failed a route. This will avoid re-using the node in routes for now,
 357         /// with an expotnential decay in node "badness". Note that there is deliberately no
 358         /// mark_channel_bad as a node may simply lie and suggest that an upstream channel from it is
 359         /// what failed the route and not the node itself. Instead, setting the blamed_upstream_node
 360         /// boolean will reduce the penalty, returning the node to usability faster. If the node is
 361         /// behaving correctly, it will disable the failing channel and we will use it again next time.
 362         pub fn mark_node_bad(&self, _node_id: &PublicKey, _blamed_upstream_node: bool) {
 363                 unimplemented!();
 364         }
 365
 366         /// Gets a route from us to the given target node.
 367         /// Extra routing hops between known nodes and the target will be used if they are included in
 368         /// last_hops.
 369         /// If some channels aren't announced, it may be useful to fill in a first_hops with the
 370         /// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our
 371         /// (this Router's) view of our local channels will be ignored, and only those in first_hops
 372         /// will be used. Panics if first_hops contains channels without short_channel_ids
 373         /// (ChannelManager::list_usable_channels will never include such channels).
 374         /// The fees on channels from us to next-hops are ignored (as they are assumed to all be
 375         /// equal), however the enabled/disabled bit on such channels as well as the htlc_minimum_msat
 376         /// *is* checked as they may change based on the receiving node.
 377         pub fn get_route(&self, target: &PublicKey, first_hops: Option<&[channelmanager::ChannelDetails]>, last_hops: &[RouteHint], final_value_msat: u64, final_cltv: u32) -> Result<Route, HandleError> {
 378                 // TODO: Obviously *only* using total fee cost sucks. We should consider weighting by
 379                 // uptime/success in using a node in the past.
 380                 let network = self.network_map.read().unwrap();
 381
 382                 if *target == network.our_node_id {
 383                         return Err(HandleError{err: "Cannot generate a route to ourselves", action: None});
 384                 }
 385
 386                 // We do a dest-to-source Dijkstra's sorting by each node's distance from the destination
 387                 // plus the minimum per-HTLC fee to get from it to another node (aka "shitty A*").
 388                 // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff
 389                 // to use as the A* heuristic beyond just the cost to get one node further than the current
 390                 // one.
 391
 392                 let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes
 393                         src_node_id: network.our_node_id.clone(),
 394                         cltv_expiry_delta: 0,
 395                         htlc_minimum_msat: 0,
 396                         fee_base_msat: 0,
 397                         fee_proportional_millionths: 0,
 398                 };
 399
 400                 let mut targets = BinaryHeap::new(); //TODO: Do we care about switching to eg Fibbonaci heap?
 401                 let mut dist = HashMap::with_capacity(network.nodes.len());
 402
 403                 let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
 404                 if let Some(hops) = first_hops {
 405                         for chan in hops {
 406                                 first_hop_targets.insert(chan.remote_network_id, chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones"));
 407                         }
 408                         if first_hop_targets.is_empty() {
 409                                 return Err(HandleError{err: "Cannot route when there are no outbound routes away from us", action: None});
 410                         }
 411                 }
 412
 413                 macro_rules! add_entry {
 414                         // Adds entry which goes from the node pointed to by $directional_info to
 415                         // $dest_node_id over the channel with id $chan_id with fees described in
 416                         // $directional_info.
 417                         ( $chan_id: expr, $dest_node_id: expr, $directional_info: expr, $starting_fee_msat: expr ) => {
 418                                 //TODO: Explore simply adding fee to hit htlc_minimum_msat
 419                                 if $starting_fee_msat as u64 + final_value_msat > $directional_info.htlc_minimum_msat {
 420                                         let new_fee = $directional_info.fee_base_msat as u64 + ($starting_fee_msat + final_value_msat) * ($directional_info.fee_proportional_millionths as u64) / 1000000;
 421                                         let mut total_fee = $starting_fee_msat as u64;
 422                                         let mut hm_entry = dist.entry(&$directional_info.src_node_id);
 423                                         let old_entry = hm_entry.or_insert_with(|| {
 424                                                 let node = network.nodes.get(&$directional_info.src_node_id).unwrap();
 425                                                 (u64::max_value(),
 426                                                         node.lowest_inbound_channel_fee_base_msat as u64,
 427                                                         node.lowest_inbound_channel_fee_proportional_millionths as u64,
 428                                                         RouteHop {
 429                                                                 pubkey: PublicKey::new(),
 430                                                                 short_channel_id: 0,
 431                                                                 fee_msat: 0,
 432                                                                 cltv_expiry_delta: 0,
 433                                                 })
 434                                         });
 435                                         if $directional_info.src_node_id != network.our_node_id {
 436                                                 // Ignore new_fee for channel-from-us as we assume all channels-from-us
 437                                                 // will have the same effective-fee
 438                                                 total_fee += new_fee;
 439                                                 total_fee += old_entry.2 * (final_value_msat + total_fee) / 1000000 + old_entry.1;
 440                                         }
 441                                         let new_graph_node = RouteGraphNode {
 442                                                 pubkey: $directional_info.src_node_id,
 443                                                 lowest_fee_to_peer_through_node: total_fee,
 444                                         };
 445                                         if old_entry.0 > total_fee {
 446                                                 targets.push(new_graph_node);
 447                                                 old_entry.0 = total_fee;
 448                                                 old_entry.3 = RouteHop {
 449                                                         pubkey: $dest_node_id.clone(),
 450                                                         short_channel_id: $chan_id.clone(),
 451                                                         fee_msat: new_fee, // This field is ignored on the last-hop anyway
 452                                                         cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32,
 453                                                 }
 454                                         }
 455                                 }
 456                         };
 457                 }
 458
 459                 macro_rules! add_entries_to_cheapest_to_target_node {
 460                         ( $node: expr, $node_id: expr, $fee_to_target_msat: expr ) => {
 461                                 if first_hops.is_some() {
 462                                         if let Some(first_hop) = first_hop_targets.get(&$node_id) {
 463                                                 add_entry!(first_hop, $node_id, dummy_directional_info, $fee_to_target_msat);
 464                                         }
 465                                 }
 466
 467                                 for chan_id in $node.channels.iter() {
 468                                         let chan = network.channels.get(chan_id).unwrap();
 469                                         if chan.one_to_two.src_node_id == *$node_id {
 470                                                 // ie $node is one, ie next hop in A* is two, via the two_to_one channel
 471                                                 if first_hops.is_none() || chan.two_to_one.src_node_id != network.our_node_id {
 472                                                         if chan.two_to_one.enabled {
 473                                                                 add_entry!(chan_id, chan.one_to_two.src_node_id, chan.two_to_one, $fee_to_target_msat);
 474                                                         }
 475                                                 }
 476                                         } else {
 477                                                 if first_hops.is_none() || chan.one_to_two.src_node_id != network.our_node_id {
 478                                                         if chan.one_to_two.enabled {
 479                                                                 add_entry!(chan_id, chan.two_to_one.src_node_id, chan.one_to_two, $fee_to_target_msat);
 480                                                         }
 481                                                 }
 482                                         }
 483                                 }
 484                         };
 485                 }
 486
 487                 match network.nodes.get(target) {
 488                         None => {},
 489                         Some(node) => {
 490                                 add_entries_to_cheapest_to_target_node!(node, target, 0);
 491                         },
 492                 }
 493
 494                 for hop in last_hops.iter() {
 495                         if first_hops.is_none() || hop.src_node_id != network.our_node_id { // first_hop overrules last_hops
 496                                 if network.nodes.get(&hop.src_node_id).is_some() {
 497                                         if first_hops.is_some() {
 498                                                 if let Some(first_hop) = first_hop_targets.get(&hop.src_node_id) {
 499                                                         add_entry!(first_hop, hop.src_node_id, dummy_directional_info, 0);
 500                                                 }
 501                                         }
 502                                         add_entry!(hop.short_channel_id, target, hop, 0);
 503                                 }
 504                         }
 505                 }
 506
 507                 while let Some(RouteGraphNode { pubkey, lowest_fee_to_peer_through_node }) = targets.pop() {
 508                         if pubkey == network.our_node_id {
 509                                 let mut res = vec!(dist.remove(&network.our_node_id).unwrap().3);
 510                                 while res.last().unwrap().pubkey != *target {
 511                                         let new_entry = dist.remove(&res.last().unwrap().pubkey).unwrap().3;
 512                                         res.last_mut().unwrap().fee_msat = new_entry.fee_msat;
 513                                         res.last_mut().unwrap().cltv_expiry_delta = new_entry.cltv_expiry_delta;
 514                                         res.push(new_entry);
 515                                 }
 516                                 res.last_mut().unwrap().fee_msat = final_value_msat;
 517                                 res.last_mut().unwrap().cltv_expiry_delta = final_cltv;
 518                                 return Ok(Route {
 519                                         hops: res
 520                                 });
 521                         }
 522
 523                         match network.nodes.get(&pubkey) {
 524                                 None => {},
 525                                 Some(node) => {
 526                                         let mut fee = lowest_fee_to_peer_through_node - node.lowest_inbound_channel_fee_base_msat as u64;
 527                                         fee -= node.lowest_inbound_channel_fee_proportional_millionths as u64 * (fee + final_value_msat) / 1000000;
 528                                         add_entries_to_cheapest_to_target_node!(node, &pubkey, fee);
 529                                 },
 530                         }
 531                 }
 532
 533                 Err(HandleError{err: "Failed to find a path to the given destination", action: None})
 534         }
 535 }
 536
 537 #[cfg(test)]
 538 mod tests {
 539         use ln::channelmanager;
 540         use ln::router::{Router,NodeInfo,NetworkMap,ChannelInfo,DirectionalChannelInfo,RouteHint};
 541         use ln::msgs::GlobalFeatures;
 542
 543         use bitcoin::util::misc::hex_bytes;
 544         use bitcoin::util::hash::Sha256dHash;
 545
 546         use secp256k1::key::{PublicKey,SecretKey};
 547         use secp256k1::Secp256k1;
 548
 549         #[test]
 550         fn route_test() {
 551                 let secp_ctx = Secp256k1::new();
 552                 let our_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap()).unwrap();
 553                 let router = Router::new(our_id);
 554
 555                 // Build network from our_id to node8:
 556                 //
 557                 //        -1(1)2-  node1  -1(3)2-
 558                 //       /                       \
 559                 // our_id -1(12)2- node8 -1(13)2--- node3
 560                 //       \                       /
 561                 //        -1(2)2-  node2  -1(4)2-
 562                 //
 563                 //
 564                 // chan1  1-to-2: disabled
 565                 // chan1  2-to-1: enabled, 0 fee
 566                 //
 567                 // chan2  1-to-2: enabled, ignored fee
 568                 // chan2  2-to-1: enabled, 0 fee
 569                 //
 570                 // chan3  1-to-2: enabled, 0 fee
 571                 // chan3  2-to-1: enabled, 100 msat fee
 572                 //
 573                 // chan4  1-to-2: enabled, 100% fee
 574                 // chan4  2-to-1: enabled, 0 fee
 575                 //
 576                 // chan12 1-to-2: enabled, ignored fee
 577                 // chan12 2-to-1: enabled, 0 fee
 578                 //
 579                 // chan13 1-to-2: enabled, 200% fee
 580                 // chan13 2-to-1: enabled, 0 fee
 581                 //
 582                 //
 583                 //       -1(5)2- node4 -1(8)2--
 584                 //       |         2          |
 585                 //       |       (11)         |
 586                 //      /          1           \
 587                 // node3--1(6)2- node5 -1(9)2--- node7 (not in global route map)
 588                 //      \                      /
 589                 //       -1(7)2- node6 -1(10)2-
 590                 //
 591                 // chan5  1-to-2: enabled, 100 msat fee
 592                 // chan5  2-to-1: enabled, 0 fee
 593                 //
 594                 // chan6  1-to-2: enabled, 0 fee
 595                 // chan6  2-to-1: enabled, 0 fee
 596                 //
 597                 // chan7  1-to-2: enabled, 100% fee
 598                 // chan7  2-to-1: enabled, 0 fee
 599                 //
 600                 // chan8  1-to-2: enabled, variable fee (0 then 1000 msat)
 601                 // chan8  2-to-1: enabled, 0 fee
 602                 //
 603                 // chan9  1-to-2: enabled, 1001 msat fee
 604                 // chan9  2-to-1: enabled, 0 fee
 605                 //
 606                 // chan10 1-to-2: enabled, 0 fee
 607                 // chan10 2-to-1: enabled, 0 fee
 608                 //
 609                 // chan11 1-to-2: enabled, 0 fee
 610                 // chan11 2-to-1: enabled, 0 fee
 611
 612                 let node1 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap()).unwrap();
 613                 let node2 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0303030303030303030303030303030303030303030303030303030303030303").unwrap()[..]).unwrap()).unwrap();
 614                 let node3 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0404040404040404040404040404040404040404040404040404040404040404").unwrap()[..]).unwrap()).unwrap();
 615                 let node4 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0505050505050505050505050505050505050505050505050505050505050505").unwrap()[..]).unwrap()).unwrap();
 616                 let node5 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0606060606060606060606060606060606060606060606060606060606060606").unwrap()[..]).unwrap()).unwrap();
 617                 let node6 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0707070707070707070707070707070707070707070707070707070707070707").unwrap()[..]).unwrap()).unwrap();
 618                 let node7 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0808080808080808080808080808080808080808080808080808080808080808").unwrap()[..]).unwrap()).unwrap();
 619                 let node8 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0909090909090909090909090909090909090909090909090909090909090909").unwrap()[..]).unwrap()).unwrap();
 620
 621                 let zero_hash = Sha256dHash::from_data(&[0; 32]);
 622
 623                 {
 624                         let mut network = router.network_map.write().unwrap();
 625
 626                         network.nodes.insert(node1.clone(), NodeInfo {
 627                                 channels: vec!(NetworkMap::get_key(1, zero_hash.clone()), NetworkMap::get_key(3, zero_hash.clone())),
 628                                 lowest_inbound_channel_fee_base_msat: 100,
 629                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 630                                 features: GlobalFeatures::new(),
 631                                 last_update: 1,
 632                                 rgb: [0; 3],
 633                                 alias: [0; 32],
 634                                 addresses: Vec::new(),
 635                         });
 636                         network.channels.insert(NetworkMap::get_key(1, zero_hash.clone()), ChannelInfo {
 637                                 features: GlobalFeatures::new(),
 638                                 one_to_two: DirectionalChannelInfo {
 639                                         src_node_id: our_id.clone(),
 640                                         last_update: 0,
 641                                         enabled: false,
 642                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 643                                         htlc_minimum_msat: 0,
 644                                         fee_base_msat: u32::max_value(), // This value should be ignored
 645                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 646                                 }, two_to_one: DirectionalChannelInfo {
 647                                         src_node_id: node1.clone(),
 648                                         last_update: 0,
 649                                         enabled: true,
 650                                         cltv_expiry_delta: 0,
 651                                         htlc_minimum_msat: 0,
 652                                         fee_base_msat: 0,
 653                                         fee_proportional_millionths: 0,
 654                                 },
 655                         });
 656                         network.nodes.insert(node2.clone(), NodeInfo {
 657                                 channels: vec!(NetworkMap::get_key(2, zero_hash.clone()), NetworkMap::get_key(4, zero_hash.clone())),
 658                                 lowest_inbound_channel_fee_base_msat: 0,
 659                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 660                                 features: GlobalFeatures::new(),
 661                                 last_update: 1,
 662                                 rgb: [0; 3],
 663                                 alias: [0; 32],
 664                                 addresses: Vec::new(),
 665                         });
 666                         network.channels.insert(NetworkMap::get_key(2, zero_hash.clone()), ChannelInfo {
 667                                 features: GlobalFeatures::new(),
 668                                 one_to_two: DirectionalChannelInfo {
 669                                         src_node_id: our_id.clone(),
 670                                         last_update: 0,
 671                                         enabled: true,
 672                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 673                                         htlc_minimum_msat: 0,
 674                                         fee_base_msat: u32::max_value(), // This value should be ignored
 675                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 676                                 }, two_to_one: DirectionalChannelInfo {
 677                                         src_node_id: node2.clone(),
 678                                         last_update: 0,
 679                                         enabled: true,
 680                                         cltv_expiry_delta: 0,
 681                                         htlc_minimum_msat: 0,
 682                                         fee_base_msat: 0,
 683                                         fee_proportional_millionths: 0,
 684                                 },
 685                         });
 686                         network.nodes.insert(node8.clone(), NodeInfo {
 687                                 channels: vec!(NetworkMap::get_key(12, zero_hash.clone()), NetworkMap::get_key(13, zero_hash.clone())),
 688                                 lowest_inbound_channel_fee_base_msat: 0,
 689                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 690                                 features: GlobalFeatures::new(),
 691                                 last_update: 1,
 692                                 rgb: [0; 3],
 693                                 alias: [0; 32],
 694                                 addresses: Vec::new(),
 695                         });
 696                         network.channels.insert(NetworkMap::get_key(12, zero_hash.clone()), ChannelInfo {
 697                                 features: GlobalFeatures::new(),
 698                                 one_to_two: DirectionalChannelInfo {
 699                                         src_node_id: our_id.clone(),
 700                                         last_update: 0,
 701                                         enabled: true,
 702                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 703                                         htlc_minimum_msat: 0,
 704                                         fee_base_msat: u32::max_value(), // This value should be ignored
 705                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 706                                 }, two_to_one: DirectionalChannelInfo {
 707                                         src_node_id: node8.clone(),
 708                                         last_update: 0,
 709                                         enabled: true,
 710                                         cltv_expiry_delta: 0,
 711                                         htlc_minimum_msat: 0,
 712                                         fee_base_msat: 0,
 713                                         fee_proportional_millionths: 0,
 714                                 },
 715                         });
 716                         network.nodes.insert(node3.clone(), NodeInfo {
 717                                 channels: vec!(
 718                                         NetworkMap::get_key(3, zero_hash.clone()),
 719                                         NetworkMap::get_key(4, zero_hash.clone()),
 720                                         NetworkMap::get_key(13, zero_hash.clone()),
 721                                         NetworkMap::get_key(5, zero_hash.clone()),
 722                                         NetworkMap::get_key(6, zero_hash.clone()),
 723                                         NetworkMap::get_key(7, zero_hash.clone())),
 724                                 lowest_inbound_channel_fee_base_msat: 0,
 725                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 726                                 features: GlobalFeatures::new(),
 727                                 last_update: 1,
 728                                 rgb: [0; 3],
 729                                 alias: [0; 32],
 730                                 addresses: Vec::new(),
 731                         });
 732                         network.channels.insert(NetworkMap::get_key(3, zero_hash.clone()), ChannelInfo {
 733                                 features: GlobalFeatures::new(),
 734                                 one_to_two: DirectionalChannelInfo {
 735                                         src_node_id: node1.clone(),
 736                                         last_update: 0,
 737                                         enabled: true,
 738                                         cltv_expiry_delta: (3 << 8) | 1,
 739                                         htlc_minimum_msat: 0,
 740                                         fee_base_msat: 0,
 741                                         fee_proportional_millionths: 0,
 742                                 }, two_to_one: DirectionalChannelInfo {
 743                                         src_node_id: node3.clone(),
 744                                         last_update: 0,
 745                                         enabled: true,
 746                                         cltv_expiry_delta: (3 << 8) | 2,
 747                                         htlc_minimum_msat: 0,
 748                                         fee_base_msat: 100,
 749                                         fee_proportional_millionths: 0,
 750                                 },
 751                         });
 752                         network.channels.insert(NetworkMap::get_key(4, zero_hash.clone()), ChannelInfo {
 753                                 features: GlobalFeatures::new(),
 754                                 one_to_two: DirectionalChannelInfo {
 755                                         src_node_id: node2.clone(),
 756                                         last_update: 0,
 757                                         enabled: true,
 758                                         cltv_expiry_delta: (4 << 8) | 1,
 759                                         htlc_minimum_msat: 0,
 760                                         fee_base_msat: 0,
 761                                         fee_proportional_millionths: 1000000,
 762                                 }, two_to_one: DirectionalChannelInfo {
 763                                         src_node_id: node3.clone(),
 764                                         last_update: 0,
 765                                         enabled: true,
 766                                         cltv_expiry_delta: (4 << 8) | 2,
 767                                         htlc_minimum_msat: 0,
 768                                         fee_base_msat: 0,
 769                                         fee_proportional_millionths: 0,
 770                                 },
 771                         });
 772                         network.channels.insert(NetworkMap::get_key(13, zero_hash.clone()), ChannelInfo {
 773                                 features: GlobalFeatures::new(),
 774                                 one_to_two: DirectionalChannelInfo {
 775                                         src_node_id: node8.clone(),
 776                                         last_update: 0,
 777                                         enabled: true,
 778                                         cltv_expiry_delta: (13 << 8) | 1,
 779                                         htlc_minimum_msat: 0,
 780                                         fee_base_msat: 0,
 781                                         fee_proportional_millionths: 2000000,
 782                                 }, two_to_one: DirectionalChannelInfo {
 783                                         src_node_id: node3.clone(),
 784                                         last_update: 0,
 785                                         enabled: true,
 786                                         cltv_expiry_delta: (13 << 8) | 2,
 787                                         htlc_minimum_msat: 0,
 788                                         fee_base_msat: 0,
 789                                         fee_proportional_millionths: 0,
 790                                 },
 791                         });
 792                         network.nodes.insert(node4.clone(), NodeInfo {
 793                                 channels: vec!(NetworkMap::get_key(5, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 794                                 lowest_inbound_channel_fee_base_msat: 0,
 795                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 796                                 features: GlobalFeatures::new(),
 797                                 last_update: 1,
 798                                 rgb: [0; 3],
 799                                 alias: [0; 32],
 800                                 addresses: Vec::new(),
 801                         });
 802                         network.channels.insert(NetworkMap::get_key(5, zero_hash.clone()), ChannelInfo {
 803                                 features: GlobalFeatures::new(),
 804                                 one_to_two: DirectionalChannelInfo {
 805                                         src_node_id: node3.clone(),
 806                                         last_update: 0,
 807                                         enabled: true,
 808                                         cltv_expiry_delta: (5 << 8) | 1,
 809                                         htlc_minimum_msat: 0,
 810                                         fee_base_msat: 100,
 811                                         fee_proportional_millionths: 0,
 812                                 }, two_to_one: DirectionalChannelInfo {
 813                                         src_node_id: node4.clone(),
 814                                         last_update: 0,
 815                                         enabled: true,
 816                                         cltv_expiry_delta: (5 << 8) | 2,
 817                                         htlc_minimum_msat: 0,
 818                                         fee_base_msat: 0,
 819                                         fee_proportional_millionths: 0,
 820                                 },
 821                         });
 822                         network.nodes.insert(node5.clone(), NodeInfo {
 823                                 channels: vec!(NetworkMap::get_key(6, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 824                                 lowest_inbound_channel_fee_base_msat: 0,
 825                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 826                                 features: GlobalFeatures::new(),
 827                                 last_update: 1,
 828                                 rgb: [0; 3],
 829                                 alias: [0; 32],
 830                                 addresses: Vec::new(),
 831                         });
 832                         network.channels.insert(NetworkMap::get_key(6, zero_hash.clone()), ChannelInfo {
 833                                 features: GlobalFeatures::new(),
 834                                 one_to_two: DirectionalChannelInfo {
 835                                         src_node_id: node3.clone(),
 836                                         last_update: 0,
 837                                         enabled: true,
 838                                         cltv_expiry_delta: (6 << 8) | 1,
 839                                         htlc_minimum_msat: 0,
 840                                         fee_base_msat: 0,
 841                                         fee_proportional_millionths: 0,
 842                                 }, two_to_one: DirectionalChannelInfo {
 843                                         src_node_id: node5.clone(),
 844                                         last_update: 0,
 845                                         enabled: true,
 846                                         cltv_expiry_delta: (6 << 8) | 2,
 847                                         htlc_minimum_msat: 0,
 848                                         fee_base_msat: 0,
 849                                         fee_proportional_millionths: 0,
 850                                 },
 851                         });
 852                         network.channels.insert(NetworkMap::get_key(11, zero_hash.clone()), ChannelInfo {
 853                                 features: GlobalFeatures::new(),
 854                                 one_to_two: DirectionalChannelInfo {
 855                                         src_node_id: node5.clone(),
 856                                         last_update: 0,
 857                                         enabled: true,
 858                                         cltv_expiry_delta: (11 << 8) | 1,
 859                                         htlc_minimum_msat: 0,
 860                                         fee_base_msat: 0,
 861                                         fee_proportional_millionths: 0,
 862                                 }, two_to_one: DirectionalChannelInfo {
 863                                         src_node_id: node4.clone(),
 864                                         last_update: 0,
 865                                         enabled: true,
 866                                         cltv_expiry_delta: (11 << 8) | 2,
 867                                         htlc_minimum_msat: 0,
 868                                         fee_base_msat: 0,
 869                                         fee_proportional_millionths: 0,
 870                                 },
 871                         });
 872                         network.nodes.insert(node6.clone(), NodeInfo {
 873                                 channels: vec!(NetworkMap::get_key(7, zero_hash.clone())),
 874                                 lowest_inbound_channel_fee_base_msat: 0,
 875                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 876                                 features: GlobalFeatures::new(),
 877                                 last_update: 1,
 878                                 rgb: [0; 3],
 879                                 alias: [0; 32],
 880                                 addresses: Vec::new(),
 881                         });
 882                         network.channels.insert(NetworkMap::get_key(7, zero_hash.clone()), ChannelInfo {
 883                                 features: GlobalFeatures::new(),
 884                                 one_to_two: DirectionalChannelInfo {
 885                                         src_node_id: node3.clone(),
 886                                         last_update: 0,
 887                                         enabled: true,
 888                                         cltv_expiry_delta: (7 << 8) | 1,
 889                                         htlc_minimum_msat: 0,
 890                                         fee_base_msat: 0,
 891                                         fee_proportional_millionths: 1000000,
 892                                 }, two_to_one: DirectionalChannelInfo {
 893                                         src_node_id: node6.clone(),
 894                                         last_update: 0,
 895                                         enabled: true,
 896                                         cltv_expiry_delta: (7 << 8) | 2,
 897                                         htlc_minimum_msat: 0,
 898                                         fee_base_msat: 0,
 899                                         fee_proportional_millionths: 0,
 900                                 },
 901                         });
 902                 }
 903
 904                 { // Simple route to 3 via 2
 905                         let route = router.get_route(&node3, None, &Vec::new(), 100, 42).unwrap();
 906                         assert_eq!(route.hops.len(), 2);
 907
 908                         assert_eq!(route.hops[0].pubkey, node2);
 909                         assert_eq!(route.hops[0].short_channel_id, 2);
 910                         assert_eq!(route.hops[0].fee_msat, 100);
 911                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
 912
 913                         assert_eq!(route.hops[1].pubkey, node3);
 914                         assert_eq!(route.hops[1].short_channel_id, 4);
 915                         assert_eq!(route.hops[1].fee_msat, 100);
 916                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
 917                 }
 918
 919                 { // Route to 1 via 2 and 3 because our channel to 1 is disabled
 920                         let route = router.get_route(&node1, None, &Vec::new(), 100, 42).unwrap();
 921                         assert_eq!(route.hops.len(), 3);
 922
 923                         assert_eq!(route.hops[0].pubkey, node2);
 924                         assert_eq!(route.hops[0].short_channel_id, 2);
 925                         assert_eq!(route.hops[0].fee_msat, 200);
 926                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
 927
 928                         assert_eq!(route.hops[1].pubkey, node3);
 929                         assert_eq!(route.hops[1].short_channel_id, 4);
 930                         assert_eq!(route.hops[1].fee_msat, 100);
 931                         assert_eq!(route.hops[1].cltv_expiry_delta, (3 << 8) | 2);
 932
 933                         assert_eq!(route.hops[2].pubkey, node1);
 934                         assert_eq!(route.hops[2].short_channel_id, 3);
 935                         assert_eq!(route.hops[2].fee_msat, 100);
 936                         assert_eq!(route.hops[2].cltv_expiry_delta, 42);
 937                 }
 938
 939                 { // If we specify a channel to node8, that overrides our local channel view and that gets used
 940                         let our_chans = vec![channelmanager::ChannelDetails {
 941                                 channel_id: [0; 32],
 942                                 short_channel_id: Some(42),
 943                                 remote_network_id: node8.clone(),
 944                                 channel_value_satoshis: 0,
 945                                 user_id: 0,
 946                         }];
 947                         let route = router.get_route(&node3, Some(&our_chans), &Vec::new(), 100, 42).unwrap();
 948                         assert_eq!(route.hops.len(), 2);
 949
 950                         assert_eq!(route.hops[0].pubkey, node8);
 951                         assert_eq!(route.hops[0].short_channel_id, 42);
 952                         assert_eq!(route.hops[0].fee_msat, 200);
 953                         assert_eq!(route.hops[0].cltv_expiry_delta, (13 << 8) | 1);
 954
 955                         assert_eq!(route.hops[1].pubkey, node3);
 956                         assert_eq!(route.hops[1].short_channel_id, 13);
 957                         assert_eq!(route.hops[1].fee_msat, 100);
 958                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
 959                 }
 960
 961                 let mut last_hops = vec!(RouteHint {
 962                                 src_node_id: node4.clone(),
 963                                 short_channel_id: 8,
 964                                 fee_base_msat: 0,
 965                                 fee_proportional_millionths: 0,
 966                                 cltv_expiry_delta: (8 << 8) | 1,
 967                                 htlc_minimum_msat: 0,
 968                         }, RouteHint {
 969                                 src_node_id: node5.clone(),
 970                                 short_channel_id: 9,
 971                                 fee_base_msat: 1001,
 972                                 fee_proportional_millionths: 0,
 973                                 cltv_expiry_delta: (9 << 8) | 1,
 974                                 htlc_minimum_msat: 0,
 975                         }, RouteHint {
 976                                 src_node_id: node6.clone(),
 977                                 short_channel_id: 10,
 978                                 fee_base_msat: 0,
 979                                 fee_proportional_millionths: 0,
 980                                 cltv_expiry_delta: (10 << 8) | 1,
 981                                 htlc_minimum_msat: 0,
 982                         });
 983
 984                 { // Simple test across 2, 3, 5, and 4 via a last_hop channel
 985                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
 986                         assert_eq!(route.hops.len(), 5);
 987
 988                         assert_eq!(route.hops[0].pubkey, node2);
 989                         assert_eq!(route.hops[0].short_channel_id, 2);
 990                         assert_eq!(route.hops[0].fee_msat, 100);
 991                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
 992
 993                         assert_eq!(route.hops[1].pubkey, node3);
 994                         assert_eq!(route.hops[1].short_channel_id, 4);
 995                         assert_eq!(route.hops[1].fee_msat, 0);
 996                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
 997
 998                         assert_eq!(route.hops[2].pubkey, node5);
 999                         assert_eq!(route.hops[2].short_channel_id, 6);
1000                         assert_eq!(route.hops[2].fee_msat, 0);
1001                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1002
1003                         assert_eq!(route.hops[3].pubkey, node4);
1004                         assert_eq!(route.hops[3].short_channel_id, 11);
1005                         assert_eq!(route.hops[3].fee_msat, 0);
1006                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1007
1008                         assert_eq!(route.hops[4].pubkey, node7);
1009                         assert_eq!(route.hops[4].short_channel_id, 8);
1010                         assert_eq!(route.hops[4].fee_msat, 100);
1011                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1012                 }
1013
1014                 { // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
1015                         let our_chans = vec![channelmanager::ChannelDetails {
1016                                 channel_id: [0; 32],
1017                                 short_channel_id: Some(42),
1018                                 remote_network_id: node4.clone(),
1019                                 channel_value_satoshis: 0,
1020                                 user_id: 0,
1021                         }];
1022                         let route = router.get_route(&node7, Some(&our_chans), &last_hops, 100, 42).unwrap();
1023                         assert_eq!(route.hops.len(), 2);
1024
1025                         assert_eq!(route.hops[0].pubkey, node4);
1026                         assert_eq!(route.hops[0].short_channel_id, 42);
1027                         assert_eq!(route.hops[0].fee_msat, 0);
1028                         assert_eq!(route.hops[0].cltv_expiry_delta, (8 << 8) | 1);
1029
1030                         assert_eq!(route.hops[1].pubkey, node7);
1031                         assert_eq!(route.hops[1].short_channel_id, 8);
1032                         assert_eq!(route.hops[1].fee_msat, 100);
1033                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
1034                 }
1035
1036                 last_hops[0].fee_base_msat = 1000;
1037
1038                 { // Revert to via 6 as the fee on 8 goes up
1039                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
1040                         assert_eq!(route.hops.len(), 4);
1041
1042                         assert_eq!(route.hops[0].pubkey, node2);
1043                         assert_eq!(route.hops[0].short_channel_id, 2);
1044                         assert_eq!(route.hops[0].fee_msat, 200); // fee increased as its % of value transferred across node
1045                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1046
1047                         assert_eq!(route.hops[1].pubkey, node3);
1048                         assert_eq!(route.hops[1].short_channel_id, 4);
1049                         assert_eq!(route.hops[1].fee_msat, 100);
1050                         assert_eq!(route.hops[1].cltv_expiry_delta, (7 << 8) | 1);
1051
1052                         assert_eq!(route.hops[2].pubkey, node6);
1053                         assert_eq!(route.hops[2].short_channel_id, 7);
1054                         assert_eq!(route.hops[2].fee_msat, 0);
1055                         assert_eq!(route.hops[2].cltv_expiry_delta, (10 << 8) | 1);
1056
1057                         assert_eq!(route.hops[3].pubkey, node7);
1058                         assert_eq!(route.hops[3].short_channel_id, 10);
1059                         assert_eq!(route.hops[3].fee_msat, 100);
1060                         assert_eq!(route.hops[3].cltv_expiry_delta, 42);
1061                 }
1062
1063                 { // ...but still use 8 for larger payments as 6 has a variable feerate
1064                         let route = router.get_route(&node7, None, &last_hops, 2000, 42).unwrap();
1065                         assert_eq!(route.hops.len(), 5);
1066
1067                         assert_eq!(route.hops[0].pubkey, node2);
1068                         assert_eq!(route.hops[0].short_channel_id, 2);
1069                         assert_eq!(route.hops[0].fee_msat, 3000);
1070                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1071
1072                         assert_eq!(route.hops[1].pubkey, node3);
1073                         assert_eq!(route.hops[1].short_channel_id, 4);
1074                         assert_eq!(route.hops[1].fee_msat, 0);
1075                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
1076
1077                         assert_eq!(route.hops[2].pubkey, node5);
1078                         assert_eq!(route.hops[2].short_channel_id, 6);
1079                         assert_eq!(route.hops[2].fee_msat, 0);
1080                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1081
1082                         assert_eq!(route.hops[3].pubkey, node4);
1083                         assert_eq!(route.hops[3].short_channel_id, 11);
1084                         assert_eq!(route.hops[3].fee_msat, 1000);
1085                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1086
1087                         assert_eq!(route.hops[4].pubkey, node7);
1088                         assert_eq!(route.hops[4].short_channel_id, 8);
1089                         assert_eq!(route.hops[4].fee_msat, 2000);
1090                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1091                 }
1092         }
1093 }