_ 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, in excess of the current block height.
  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                                 let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
 407                                 if chan.remote_network_id == *target {
 408                                         return Ok(Route {
 409                                                 hops: vec![RouteHop {
 410                                                         pubkey: chan.remote_network_id,
 411                                                         short_channel_id,
 412                                                         fee_msat: final_value_msat,
 413                                                         cltv_expiry_delta: final_cltv,
 414                                                 }],
 415                                         });
 416                                 }
 417                                 first_hop_targets.insert(chan.remote_network_id, short_channel_id);
 418                         }
 419                         if first_hop_targets.is_empty() {
 420                                 return Err(HandleError{err: "Cannot route when there are no outbound routes away from us", action: None});
 421                         }
 422                 }
 423
 424                 macro_rules! add_entry {
 425                         // Adds entry which goes from the node pointed to by $directional_info to
 426                         // $dest_node_id over the channel with id $chan_id with fees described in
 427                         // $directional_info.
 428                         ( $chan_id: expr, $dest_node_id: expr, $directional_info: expr, $starting_fee_msat: expr ) => {
 429                                 //TODO: Explore simply adding fee to hit htlc_minimum_msat
 430                                 if $starting_fee_msat as u64 + final_value_msat > $directional_info.htlc_minimum_msat {
 431                                         let proportional_fee_millions = ($starting_fee_msat + final_value_msat).checked_mul($directional_info.fee_proportional_millionths as u64);
 432                                         if let Some(proportional_fee) = proportional_fee_millions {
 433                                                 let new_fee = $directional_info.fee_base_msat as u64 + proportional_fee / 1000000;
 434                                                 let mut total_fee = $starting_fee_msat as u64;
 435                                                 let mut hm_entry = dist.entry(&$directional_info.src_node_id);
 436                                                 let old_entry = hm_entry.or_insert_with(|| {
 437                                                         let node = network.nodes.get(&$directional_info.src_node_id).unwrap();
 438                                                         (u64::max_value(),
 439                                                                 node.lowest_inbound_channel_fee_base_msat as u64,
 440                                                                 node.lowest_inbound_channel_fee_proportional_millionths as u64,
 441                                                                 RouteHop {
 442                                                                         pubkey: PublicKey::new(),
 443                                                                         short_channel_id: 0,
 444                                                                         fee_msat: 0,
 445                                                                         cltv_expiry_delta: 0,
 446                                                         })
 447                                                 });
 448                                                 if $directional_info.src_node_id != network.our_node_id {
 449                                                         // Ignore new_fee for channel-from-us as we assume all channels-from-us
 450                                                         // will have the same effective-fee
 451                                                         total_fee += new_fee;
 452                                                         total_fee += old_entry.2 * (final_value_msat + total_fee) / 1000000 + old_entry.1;
 453                                                 }
 454                                                 let new_graph_node = RouteGraphNode {
 455                                                         pubkey: $directional_info.src_node_id,
 456                                                         lowest_fee_to_peer_through_node: total_fee,
 457                                                 };
 458                                                 if old_entry.0 > total_fee {
 459                                                         targets.push(new_graph_node);
 460                                                         old_entry.0 = total_fee;
 461                                                         old_entry.3 = RouteHop {
 462                                                                 pubkey: $dest_node_id.clone(),
 463                                                                 short_channel_id: $chan_id.clone(),
 464                                                                 fee_msat: new_fee, // This field is ignored on the last-hop anyway
 465                                                                 cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32,
 466                                                         }
 467                                                 }
 468                                         }
 469                                 }
 470                         };
 471                 }
 472
 473                 macro_rules! add_entries_to_cheapest_to_target_node {
 474                         ( $node: expr, $node_id: expr, $fee_to_target_msat: expr ) => {
 475                                 if first_hops.is_some() {
 476                                         if let Some(first_hop) = first_hop_targets.get(&$node_id) {
 477                                                 add_entry!(first_hop, $node_id, dummy_directional_info, $fee_to_target_msat);
 478                                         }
 479                                 }
 480
 481                                 for chan_id in $node.channels.iter() {
 482                                         let chan = network.channels.get(chan_id).unwrap();
 483                                         if chan.one_to_two.src_node_id == *$node_id {
 484                                                 // ie $node is one, ie next hop in A* is two, via the two_to_one channel
 485                                                 if first_hops.is_none() || chan.two_to_one.src_node_id != network.our_node_id {
 486                                                         if chan.two_to_one.enabled {
 487                                                                 add_entry!(chan_id, chan.one_to_two.src_node_id, chan.two_to_one, $fee_to_target_msat);
 488                                                         }
 489                                                 }
 490                                         } else {
 491                                                 if first_hops.is_none() || chan.one_to_two.src_node_id != network.our_node_id {
 492                                                         if chan.one_to_two.enabled {
 493                                                                 add_entry!(chan_id, chan.two_to_one.src_node_id, chan.one_to_two, $fee_to_target_msat);
 494                                                         }
 495                                                 }
 496                                         }
 497                                 }
 498                         };
 499                 }
 500
 501                 match network.nodes.get(target) {
 502                         None => {},
 503                         Some(node) => {
 504                                 add_entries_to_cheapest_to_target_node!(node, target, 0);
 505                         },
 506                 }
 507
 508                 for hop in last_hops.iter() {
 509                         if first_hops.is_none() || hop.src_node_id != network.our_node_id { // first_hop overrules last_hops
 510                                 if network.nodes.get(&hop.src_node_id).is_some() {
 511                                         if first_hops.is_some() {
 512                                                 if let Some(first_hop) = first_hop_targets.get(&hop.src_node_id) {
 513                                                         add_entry!(first_hop, hop.src_node_id, dummy_directional_info, 0);
 514                                                 }
 515                                         }
 516                                         add_entry!(hop.short_channel_id, target, hop, 0);
 517                                 }
 518                         }
 519                 }
 520
 521                 while let Some(RouteGraphNode { pubkey, lowest_fee_to_peer_through_node }) = targets.pop() {
 522                         if pubkey == network.our_node_id {
 523                                 let mut res = vec!(dist.remove(&network.our_node_id).unwrap().3);
 524                                 while res.last().unwrap().pubkey != *target {
 525                                         let new_entry = dist.remove(&res.last().unwrap().pubkey).unwrap().3;
 526                                         res.last_mut().unwrap().fee_msat = new_entry.fee_msat;
 527                                         res.last_mut().unwrap().cltv_expiry_delta = new_entry.cltv_expiry_delta;
 528                                         res.push(new_entry);
 529                                 }
 530                                 res.last_mut().unwrap().fee_msat = final_value_msat;
 531                                 res.last_mut().unwrap().cltv_expiry_delta = final_cltv;
 532                                 return Ok(Route {
 533                                         hops: res
 534                                 });
 535                         }
 536
 537                         match network.nodes.get(&pubkey) {
 538                                 None => {},
 539                                 Some(node) => {
 540                                         let mut fee = lowest_fee_to_peer_through_node - node.lowest_inbound_channel_fee_base_msat as u64;
 541                                         fee -= node.lowest_inbound_channel_fee_proportional_millionths as u64 * (fee + final_value_msat) / 1000000;
 542                                         add_entries_to_cheapest_to_target_node!(node, &pubkey, fee);
 543                                 },
 544                         }
 545                 }
 546
 547                 Err(HandleError{err: "Failed to find a path to the given destination", action: None})
 548         }
 549 }
 550
 551 #[cfg(test)]
 552 mod tests {
 553         use ln::channelmanager;
 554         use ln::router::{Router,NodeInfo,NetworkMap,ChannelInfo,DirectionalChannelInfo,RouteHint};
 555         use ln::msgs::GlobalFeatures;
 556
 557         use bitcoin::util::misc::hex_bytes;
 558         use bitcoin::util::hash::Sha256dHash;
 559
 560         use secp256k1::key::{PublicKey,SecretKey};
 561         use secp256k1::Secp256k1;
 562
 563         #[test]
 564         fn route_test() {
 565                 let secp_ctx = Secp256k1::new();
 566                 let our_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap()).unwrap();
 567                 let router = Router::new(our_id);
 568
 569                 // Build network from our_id to node8:
 570                 //
 571                 //        -1(1)2-  node1  -1(3)2-
 572                 //       /                       \
 573                 // our_id -1(12)2- node8 -1(13)2--- node3
 574                 //       \                       /
 575                 //        -1(2)2-  node2  -1(4)2-
 576                 //
 577                 //
 578                 // chan1  1-to-2: disabled
 579                 // chan1  2-to-1: enabled, 0 fee
 580                 //
 581                 // chan2  1-to-2: enabled, ignored fee
 582                 // chan2  2-to-1: enabled, 0 fee
 583                 //
 584                 // chan3  1-to-2: enabled, 0 fee
 585                 // chan3  2-to-1: enabled, 100 msat fee
 586                 //
 587                 // chan4  1-to-2: enabled, 100% fee
 588                 // chan4  2-to-1: enabled, 0 fee
 589                 //
 590                 // chan12 1-to-2: enabled, ignored fee
 591                 // chan12 2-to-1: enabled, 0 fee
 592                 //
 593                 // chan13 1-to-2: enabled, 200% fee
 594                 // chan13 2-to-1: enabled, 0 fee
 595                 //
 596                 //
 597                 //       -1(5)2- node4 -1(8)2--
 598                 //       |         2          |
 599                 //       |       (11)         |
 600                 //      /          1           \
 601                 // node3--1(6)2- node5 -1(9)2--- node7 (not in global route map)
 602                 //      \                      /
 603                 //       -1(7)2- node6 -1(10)2-
 604                 //
 605                 // chan5  1-to-2: enabled, 100 msat fee
 606                 // chan5  2-to-1: enabled, 0 fee
 607                 //
 608                 // chan6  1-to-2: enabled, 0 fee
 609                 // chan6  2-to-1: enabled, 0 fee
 610                 //
 611                 // chan7  1-to-2: enabled, 100% fee
 612                 // chan7  2-to-1: enabled, 0 fee
 613                 //
 614                 // chan8  1-to-2: enabled, variable fee (0 then 1000 msat)
 615                 // chan8  2-to-1: enabled, 0 fee
 616                 //
 617                 // chan9  1-to-2: enabled, 1001 msat fee
 618                 // chan9  2-to-1: enabled, 0 fee
 619                 //
 620                 // chan10 1-to-2: enabled, 0 fee
 621                 // chan10 2-to-1: enabled, 0 fee
 622                 //
 623                 // chan11 1-to-2: enabled, 0 fee
 624                 // chan11 2-to-1: enabled, 0 fee
 625
 626                 let node1 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap()).unwrap();
 627                 let node2 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0303030303030303030303030303030303030303030303030303030303030303").unwrap()[..]).unwrap()).unwrap();
 628                 let node3 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0404040404040404040404040404040404040404040404040404040404040404").unwrap()[..]).unwrap()).unwrap();
 629                 let node4 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0505050505050505050505050505050505050505050505050505050505050505").unwrap()[..]).unwrap()).unwrap();
 630                 let node5 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0606060606060606060606060606060606060606060606060606060606060606").unwrap()[..]).unwrap()).unwrap();
 631                 let node6 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0707070707070707070707070707070707070707070707070707070707070707").unwrap()[..]).unwrap()).unwrap();
 632                 let node7 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0808080808080808080808080808080808080808080808080808080808080808").unwrap()[..]).unwrap()).unwrap();
 633                 let node8 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex_bytes("0909090909090909090909090909090909090909090909090909090909090909").unwrap()[..]).unwrap()).unwrap();
 634
 635                 let zero_hash = Sha256dHash::from_data(&[0; 32]);
 636
 637                 {
 638                         let mut network = router.network_map.write().unwrap();
 639
 640                         network.nodes.insert(node1.clone(), NodeInfo {
 641                                 channels: vec!(NetworkMap::get_key(1, zero_hash.clone()), NetworkMap::get_key(3, zero_hash.clone())),
 642                                 lowest_inbound_channel_fee_base_msat: 100,
 643                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 644                                 features: GlobalFeatures::new(),
 645                                 last_update: 1,
 646                                 rgb: [0; 3],
 647                                 alias: [0; 32],
 648                                 addresses: Vec::new(),
 649                         });
 650                         network.channels.insert(NetworkMap::get_key(1, zero_hash.clone()), ChannelInfo {
 651                                 features: GlobalFeatures::new(),
 652                                 one_to_two: DirectionalChannelInfo {
 653                                         src_node_id: our_id.clone(),
 654                                         last_update: 0,
 655                                         enabled: false,
 656                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 657                                         htlc_minimum_msat: 0,
 658                                         fee_base_msat: u32::max_value(), // This value should be ignored
 659                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 660                                 }, two_to_one: DirectionalChannelInfo {
 661                                         src_node_id: node1.clone(),
 662                                         last_update: 0,
 663                                         enabled: true,
 664                                         cltv_expiry_delta: 0,
 665                                         htlc_minimum_msat: 0,
 666                                         fee_base_msat: 0,
 667                                         fee_proportional_millionths: 0,
 668                                 },
 669                         });
 670                         network.nodes.insert(node2.clone(), NodeInfo {
 671                                 channels: vec!(NetworkMap::get_key(2, zero_hash.clone()), NetworkMap::get_key(4, zero_hash.clone())),
 672                                 lowest_inbound_channel_fee_base_msat: 0,
 673                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 674                                 features: GlobalFeatures::new(),
 675                                 last_update: 1,
 676                                 rgb: [0; 3],
 677                                 alias: [0; 32],
 678                                 addresses: Vec::new(),
 679                         });
 680                         network.channels.insert(NetworkMap::get_key(2, zero_hash.clone()), ChannelInfo {
 681                                 features: GlobalFeatures::new(),
 682                                 one_to_two: DirectionalChannelInfo {
 683                                         src_node_id: our_id.clone(),
 684                                         last_update: 0,
 685                                         enabled: true,
 686                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 687                                         htlc_minimum_msat: 0,
 688                                         fee_base_msat: u32::max_value(), // This value should be ignored
 689                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 690                                 }, two_to_one: DirectionalChannelInfo {
 691                                         src_node_id: node2.clone(),
 692                                         last_update: 0,
 693                                         enabled: true,
 694                                         cltv_expiry_delta: 0,
 695                                         htlc_minimum_msat: 0,
 696                                         fee_base_msat: 0,
 697                                         fee_proportional_millionths: 0,
 698                                 },
 699                         });
 700                         network.nodes.insert(node8.clone(), NodeInfo {
 701                                 channels: vec!(NetworkMap::get_key(12, zero_hash.clone()), NetworkMap::get_key(13, zero_hash.clone())),
 702                                 lowest_inbound_channel_fee_base_msat: 0,
 703                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 704                                 features: GlobalFeatures::new(),
 705                                 last_update: 1,
 706                                 rgb: [0; 3],
 707                                 alias: [0; 32],
 708                                 addresses: Vec::new(),
 709                         });
 710                         network.channels.insert(NetworkMap::get_key(12, zero_hash.clone()), ChannelInfo {
 711                                 features: GlobalFeatures::new(),
 712                                 one_to_two: DirectionalChannelInfo {
 713                                         src_node_id: our_id.clone(),
 714                                         last_update: 0,
 715                                         enabled: true,
 716                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 717                                         htlc_minimum_msat: 0,
 718                                         fee_base_msat: u32::max_value(), // This value should be ignored
 719                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 720                                 }, two_to_one: DirectionalChannelInfo {
 721                                         src_node_id: node8.clone(),
 722                                         last_update: 0,
 723                                         enabled: true,
 724                                         cltv_expiry_delta: 0,
 725                                         htlc_minimum_msat: 0,
 726                                         fee_base_msat: 0,
 727                                         fee_proportional_millionths: 0,
 728                                 },
 729                         });
 730                         network.nodes.insert(node3.clone(), NodeInfo {
 731                                 channels: vec!(
 732                                         NetworkMap::get_key(3, zero_hash.clone()),
 733                                         NetworkMap::get_key(4, zero_hash.clone()),
 734                                         NetworkMap::get_key(13, zero_hash.clone()),
 735                                         NetworkMap::get_key(5, zero_hash.clone()),
 736                                         NetworkMap::get_key(6, zero_hash.clone()),
 737                                         NetworkMap::get_key(7, zero_hash.clone())),
 738                                 lowest_inbound_channel_fee_base_msat: 0,
 739                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 740                                 features: GlobalFeatures::new(),
 741                                 last_update: 1,
 742                                 rgb: [0; 3],
 743                                 alias: [0; 32],
 744                                 addresses: Vec::new(),
 745                         });
 746                         network.channels.insert(NetworkMap::get_key(3, zero_hash.clone()), ChannelInfo {
 747                                 features: GlobalFeatures::new(),
 748                                 one_to_two: DirectionalChannelInfo {
 749                                         src_node_id: node1.clone(),
 750                                         last_update: 0,
 751                                         enabled: true,
 752                                         cltv_expiry_delta: (3 << 8) | 1,
 753                                         htlc_minimum_msat: 0,
 754                                         fee_base_msat: 0,
 755                                         fee_proportional_millionths: 0,
 756                                 }, two_to_one: DirectionalChannelInfo {
 757                                         src_node_id: node3.clone(),
 758                                         last_update: 0,
 759                                         enabled: true,
 760                                         cltv_expiry_delta: (3 << 8) | 2,
 761                                         htlc_minimum_msat: 0,
 762                                         fee_base_msat: 100,
 763                                         fee_proportional_millionths: 0,
 764                                 },
 765                         });
 766                         network.channels.insert(NetworkMap::get_key(4, zero_hash.clone()), ChannelInfo {
 767                                 features: GlobalFeatures::new(),
 768                                 one_to_two: DirectionalChannelInfo {
 769                                         src_node_id: node2.clone(),
 770                                         last_update: 0,
 771                                         enabled: true,
 772                                         cltv_expiry_delta: (4 << 8) | 1,
 773                                         htlc_minimum_msat: 0,
 774                                         fee_base_msat: 0,
 775                                         fee_proportional_millionths: 1000000,
 776                                 }, two_to_one: DirectionalChannelInfo {
 777                                         src_node_id: node3.clone(),
 778                                         last_update: 0,
 779                                         enabled: true,
 780                                         cltv_expiry_delta: (4 << 8) | 2,
 781                                         htlc_minimum_msat: 0,
 782                                         fee_base_msat: 0,
 783                                         fee_proportional_millionths: 0,
 784                                 },
 785                         });
 786                         network.channels.insert(NetworkMap::get_key(13, zero_hash.clone()), ChannelInfo {
 787                                 features: GlobalFeatures::new(),
 788                                 one_to_two: DirectionalChannelInfo {
 789                                         src_node_id: node8.clone(),
 790                                         last_update: 0,
 791                                         enabled: true,
 792                                         cltv_expiry_delta: (13 << 8) | 1,
 793                                         htlc_minimum_msat: 0,
 794                                         fee_base_msat: 0,
 795                                         fee_proportional_millionths: 2000000,
 796                                 }, two_to_one: DirectionalChannelInfo {
 797                                         src_node_id: node3.clone(),
 798                                         last_update: 0,
 799                                         enabled: true,
 800                                         cltv_expiry_delta: (13 << 8) | 2,
 801                                         htlc_minimum_msat: 0,
 802                                         fee_base_msat: 0,
 803                                         fee_proportional_millionths: 0,
 804                                 },
 805                         });
 806                         network.nodes.insert(node4.clone(), NodeInfo {
 807                                 channels: vec!(NetworkMap::get_key(5, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 808                                 lowest_inbound_channel_fee_base_msat: 0,
 809                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 810                                 features: GlobalFeatures::new(),
 811                                 last_update: 1,
 812                                 rgb: [0; 3],
 813                                 alias: [0; 32],
 814                                 addresses: Vec::new(),
 815                         });
 816                         network.channels.insert(NetworkMap::get_key(5, zero_hash.clone()), ChannelInfo {
 817                                 features: GlobalFeatures::new(),
 818                                 one_to_two: DirectionalChannelInfo {
 819                                         src_node_id: node3.clone(),
 820                                         last_update: 0,
 821                                         enabled: true,
 822                                         cltv_expiry_delta: (5 << 8) | 1,
 823                                         htlc_minimum_msat: 0,
 824                                         fee_base_msat: 100,
 825                                         fee_proportional_millionths: 0,
 826                                 }, two_to_one: DirectionalChannelInfo {
 827                                         src_node_id: node4.clone(),
 828                                         last_update: 0,
 829                                         enabled: true,
 830                                         cltv_expiry_delta: (5 << 8) | 2,
 831                                         htlc_minimum_msat: 0,
 832                                         fee_base_msat: 0,
 833                                         fee_proportional_millionths: 0,
 834                                 },
 835                         });
 836                         network.nodes.insert(node5.clone(), NodeInfo {
 837                                 channels: vec!(NetworkMap::get_key(6, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 838                                 lowest_inbound_channel_fee_base_msat: 0,
 839                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 840                                 features: GlobalFeatures::new(),
 841                                 last_update: 1,
 842                                 rgb: [0; 3],
 843                                 alias: [0; 32],
 844                                 addresses: Vec::new(),
 845                         });
 846                         network.channels.insert(NetworkMap::get_key(6, zero_hash.clone()), ChannelInfo {
 847                                 features: GlobalFeatures::new(),
 848                                 one_to_two: DirectionalChannelInfo {
 849                                         src_node_id: node3.clone(),
 850                                         last_update: 0,
 851                                         enabled: true,
 852                                         cltv_expiry_delta: (6 << 8) | 1,
 853                                         htlc_minimum_msat: 0,
 854                                         fee_base_msat: 0,
 855                                         fee_proportional_millionths: 0,
 856                                 }, two_to_one: DirectionalChannelInfo {
 857                                         src_node_id: node5.clone(),
 858                                         last_update: 0,
 859                                         enabled: true,
 860                                         cltv_expiry_delta: (6 << 8) | 2,
 861                                         htlc_minimum_msat: 0,
 862                                         fee_base_msat: 0,
 863                                         fee_proportional_millionths: 0,
 864                                 },
 865                         });
 866                         network.channels.insert(NetworkMap::get_key(11, zero_hash.clone()), ChannelInfo {
 867                                 features: GlobalFeatures::new(),
 868                                 one_to_two: DirectionalChannelInfo {
 869                                         src_node_id: node5.clone(),
 870                                         last_update: 0,
 871                                         enabled: true,
 872                                         cltv_expiry_delta: (11 << 8) | 1,
 873                                         htlc_minimum_msat: 0,
 874                                         fee_base_msat: 0,
 875                                         fee_proportional_millionths: 0,
 876                                 }, two_to_one: DirectionalChannelInfo {
 877                                         src_node_id: node4.clone(),
 878                                         last_update: 0,
 879                                         enabled: true,
 880                                         cltv_expiry_delta: (11 << 8) | 2,
 881                                         htlc_minimum_msat: 0,
 882                                         fee_base_msat: 0,
 883                                         fee_proportional_millionths: 0,
 884                                 },
 885                         });
 886                         network.nodes.insert(node6.clone(), NodeInfo {
 887                                 channels: vec!(NetworkMap::get_key(7, zero_hash.clone())),
 888                                 lowest_inbound_channel_fee_base_msat: 0,
 889                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 890                                 features: GlobalFeatures::new(),
 891                                 last_update: 1,
 892                                 rgb: [0; 3],
 893                                 alias: [0; 32],
 894                                 addresses: Vec::new(),
 895                         });
 896                         network.channels.insert(NetworkMap::get_key(7, zero_hash.clone()), ChannelInfo {
 897                                 features: GlobalFeatures::new(),
 898                                 one_to_two: DirectionalChannelInfo {
 899                                         src_node_id: node3.clone(),
 900                                         last_update: 0,
 901                                         enabled: true,
 902                                         cltv_expiry_delta: (7 << 8) | 1,
 903                                         htlc_minimum_msat: 0,
 904                                         fee_base_msat: 0,
 905                                         fee_proportional_millionths: 1000000,
 906                                 }, two_to_one: DirectionalChannelInfo {
 907                                         src_node_id: node6.clone(),
 908                                         last_update: 0,
 909                                         enabled: true,
 910                                         cltv_expiry_delta: (7 << 8) | 2,
 911                                         htlc_minimum_msat: 0,
 912                                         fee_base_msat: 0,
 913                                         fee_proportional_millionths: 0,
 914                                 },
 915                         });
 916                 }
 917
 918                 { // Simple route to 3 via 2
 919                         let route = router.get_route(&node3, None, &Vec::new(), 100, 42).unwrap();
 920                         assert_eq!(route.hops.len(), 2);
 921
 922                         assert_eq!(route.hops[0].pubkey, node2);
 923                         assert_eq!(route.hops[0].short_channel_id, 2);
 924                         assert_eq!(route.hops[0].fee_msat, 100);
 925                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
 926
 927                         assert_eq!(route.hops[1].pubkey, node3);
 928                         assert_eq!(route.hops[1].short_channel_id, 4);
 929                         assert_eq!(route.hops[1].fee_msat, 100);
 930                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
 931                 }
 932
 933                 { // Route to 1 via 2 and 3 because our channel to 1 is disabled
 934                         let route = router.get_route(&node1, None, &Vec::new(), 100, 42).unwrap();
 935                         assert_eq!(route.hops.len(), 3);
 936
 937                         assert_eq!(route.hops[0].pubkey, node2);
 938                         assert_eq!(route.hops[0].short_channel_id, 2);
 939                         assert_eq!(route.hops[0].fee_msat, 200);
 940                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
 941
 942                         assert_eq!(route.hops[1].pubkey, node3);
 943                         assert_eq!(route.hops[1].short_channel_id, 4);
 944                         assert_eq!(route.hops[1].fee_msat, 100);
 945                         assert_eq!(route.hops[1].cltv_expiry_delta, (3 << 8) | 2);
 946
 947                         assert_eq!(route.hops[2].pubkey, node1);
 948                         assert_eq!(route.hops[2].short_channel_id, 3);
 949                         assert_eq!(route.hops[2].fee_msat, 100);
 950                         assert_eq!(route.hops[2].cltv_expiry_delta, 42);
 951                 }
 952
 953                 { // If we specify a channel to node8, that overrides our local channel view and that gets used
 954                         let our_chans = vec![channelmanager::ChannelDetails {
 955                                 channel_id: [0; 32],
 956                                 short_channel_id: Some(42),
 957                                 remote_network_id: node8.clone(),
 958                                 channel_value_satoshis: 0,
 959                                 user_id: 0,
 960                         }];
 961                         let route = router.get_route(&node3, Some(&our_chans), &Vec::new(), 100, 42).unwrap();
 962                         assert_eq!(route.hops.len(), 2);
 963
 964                         assert_eq!(route.hops[0].pubkey, node8);
 965                         assert_eq!(route.hops[0].short_channel_id, 42);
 966                         assert_eq!(route.hops[0].fee_msat, 200);
 967                         assert_eq!(route.hops[0].cltv_expiry_delta, (13 << 8) | 1);
 968
 969                         assert_eq!(route.hops[1].pubkey, node3);
 970                         assert_eq!(route.hops[1].short_channel_id, 13);
 971                         assert_eq!(route.hops[1].fee_msat, 100);
 972                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
 973                 }
 974
 975                 let mut last_hops = vec!(RouteHint {
 976                                 src_node_id: node4.clone(),
 977                                 short_channel_id: 8,
 978                                 fee_base_msat: 0,
 979                                 fee_proportional_millionths: 0,
 980                                 cltv_expiry_delta: (8 << 8) | 1,
 981                                 htlc_minimum_msat: 0,
 982                         }, RouteHint {
 983                                 src_node_id: node5.clone(),
 984                                 short_channel_id: 9,
 985                                 fee_base_msat: 1001,
 986                                 fee_proportional_millionths: 0,
 987                                 cltv_expiry_delta: (9 << 8) | 1,
 988                                 htlc_minimum_msat: 0,
 989                         }, RouteHint {
 990                                 src_node_id: node6.clone(),
 991                                 short_channel_id: 10,
 992                                 fee_base_msat: 0,
 993                                 fee_proportional_millionths: 0,
 994                                 cltv_expiry_delta: (10 << 8) | 1,
 995                                 htlc_minimum_msat: 0,
 996                         });
 997
 998                 { // Simple test across 2, 3, 5, and 4 via a last_hop channel
 999                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
1000                         assert_eq!(route.hops.len(), 5);
1001
1002                         assert_eq!(route.hops[0].pubkey, node2);
1003                         assert_eq!(route.hops[0].short_channel_id, 2);
1004                         assert_eq!(route.hops[0].fee_msat, 100);
1005                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1006
1007                         assert_eq!(route.hops[1].pubkey, node3);
1008                         assert_eq!(route.hops[1].short_channel_id, 4);
1009                         assert_eq!(route.hops[1].fee_msat, 0);
1010                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
1011
1012                         assert_eq!(route.hops[2].pubkey, node5);
1013                         assert_eq!(route.hops[2].short_channel_id, 6);
1014                         assert_eq!(route.hops[2].fee_msat, 0);
1015                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1016
1017                         assert_eq!(route.hops[3].pubkey, node4);
1018                         assert_eq!(route.hops[3].short_channel_id, 11);
1019                         assert_eq!(route.hops[3].fee_msat, 0);
1020                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1021
1022                         assert_eq!(route.hops[4].pubkey, node7);
1023                         assert_eq!(route.hops[4].short_channel_id, 8);
1024                         assert_eq!(route.hops[4].fee_msat, 100);
1025                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1026                 }
1027
1028                 { // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
1029                         let our_chans = vec![channelmanager::ChannelDetails {
1030                                 channel_id: [0; 32],
1031                                 short_channel_id: Some(42),
1032                                 remote_network_id: node4.clone(),
1033                                 channel_value_satoshis: 0,
1034                                 user_id: 0,
1035                         }];
1036                         let route = router.get_route(&node7, Some(&our_chans), &last_hops, 100, 42).unwrap();
1037                         assert_eq!(route.hops.len(), 2);
1038
1039                         assert_eq!(route.hops[0].pubkey, node4);
1040                         assert_eq!(route.hops[0].short_channel_id, 42);
1041                         assert_eq!(route.hops[0].fee_msat, 0);
1042                         assert_eq!(route.hops[0].cltv_expiry_delta, (8 << 8) | 1);
1043
1044                         assert_eq!(route.hops[1].pubkey, node7);
1045                         assert_eq!(route.hops[1].short_channel_id, 8);
1046                         assert_eq!(route.hops[1].fee_msat, 100);
1047                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
1048                 }
1049
1050                 last_hops[0].fee_base_msat = 1000;
1051
1052                 { // Revert to via 6 as the fee on 8 goes up
1053                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
1054                         assert_eq!(route.hops.len(), 4);
1055
1056                         assert_eq!(route.hops[0].pubkey, node2);
1057                         assert_eq!(route.hops[0].short_channel_id, 2);
1058                         assert_eq!(route.hops[0].fee_msat, 200); // fee increased as its % of value transferred across node
1059                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1060
1061                         assert_eq!(route.hops[1].pubkey, node3);
1062                         assert_eq!(route.hops[1].short_channel_id, 4);
1063                         assert_eq!(route.hops[1].fee_msat, 100);
1064                         assert_eq!(route.hops[1].cltv_expiry_delta, (7 << 8) | 1);
1065
1066                         assert_eq!(route.hops[2].pubkey, node6);
1067                         assert_eq!(route.hops[2].short_channel_id, 7);
1068                         assert_eq!(route.hops[2].fee_msat, 0);
1069                         assert_eq!(route.hops[2].cltv_expiry_delta, (10 << 8) | 1);
1070
1071                         assert_eq!(route.hops[3].pubkey, node7);
1072                         assert_eq!(route.hops[3].short_channel_id, 10);
1073                         assert_eq!(route.hops[3].fee_msat, 100);
1074                         assert_eq!(route.hops[3].cltv_expiry_delta, 42);
1075                 }
1076
1077                 { // ...but still use 8 for larger payments as 6 has a variable feerate
1078                         let route = router.get_route(&node7, None, &last_hops, 2000, 42).unwrap();
1079                         assert_eq!(route.hops.len(), 5);
1080
1081                         assert_eq!(route.hops[0].pubkey, node2);
1082                         assert_eq!(route.hops[0].short_channel_id, 2);
1083                         assert_eq!(route.hops[0].fee_msat, 3000);
1084                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1085
1086                         assert_eq!(route.hops[1].pubkey, node3);
1087                         assert_eq!(route.hops[1].short_channel_id, 4);
1088                         assert_eq!(route.hops[1].fee_msat, 0);
1089                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
1090
1091                         assert_eq!(route.hops[2].pubkey, node5);
1092                         assert_eq!(route.hops[2].short_channel_id, 6);
1093                         assert_eq!(route.hops[2].fee_msat, 0);
1094                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1095
1096                         assert_eq!(route.hops[3].pubkey, node4);
1097                         assert_eq!(route.hops[3].short_channel_id, 11);
1098                         assert_eq!(route.hops[3].fee_msat, 1000);
1099                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1100
1101                         assert_eq!(route.hops[4].pubkey, node7);
1102                         assert_eq!(route.hops[4].short_channel_id, 8);
1103                         assert_eq!(route.hops[4].fee_msat, 2000);
1104                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1105                 }
1106         }
1107 }