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

   1 use secp256k1::key::PublicKey;
   2 use secp256k1::{Secp256k1,Message};
   3 use secp256k1;
   4
   5 use bitcoin::util::hash::Sha256dHash;
   6 use bitcoin::blockdata::script::Builder;
   7 use bitcoin::blockdata::opcodes;
   8
   9 use chain::chaininterface::{ChainError, ChainWatchInterface};
  10 use ln::channelmanager;
  11 use ln::msgs::{ErrorAction,HandleError,RoutingMessageHandler,MsgEncodable,NetAddress,GlobalFeatures};
  12 use ln::msgs;
  13 use util::logger::Logger;
  14
  15 use std::cmp;
  16 use std::sync::{RwLock,Arc};
  17 use std::collections::{HashMap,BinaryHeap};
  18 use std::collections::hash_map::Entry;
  19 use std;
  20
  21 /// A hop in a route
  22 #[derive(Clone)]
  23 pub struct RouteHop {
  24         pub pubkey: PublicKey,
  25         /// The channel that should be used from the previous hop to reach this node.
  26         pub short_channel_id: u64,
  27         /// The fee taken on this hop. For the last hop, this should be the full value of the payment.
  28         pub fee_msat: u64,
  29         /// The CLTV delta added for this hop. For the last hop, this should be the full CLTV value
  30         /// expected at the destination, in excess of the current block height.
  31         pub cltv_expiry_delta: u32,
  32 }
  33
  34 /// A route from us through the network to a destination
  35 #[derive(Clone)]
  36 pub struct Route {
  37         /// The list of hops, NOT INCLUDING our own, where the last hop is the destination. Thus, this
  38         /// must always be at least length one. By protocol rules, this may not currently exceed 20 in
  39         /// length.
  40         pub hops: Vec<RouteHop>,
  41 }
  42
  43 struct DirectionalChannelInfo {
  44         src_node_id: PublicKey,
  45         last_update: u32,
  46         enabled: bool,
  47         cltv_expiry_delta: u16,
  48         htlc_minimum_msat: u64,
  49         fee_base_msat: u32,
  50         fee_proportional_millionths: u32,
  51 }
  52
  53 impl std::fmt::Display for DirectionalChannelInfo {
  54         fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
  55                 write!(f, "src_node_id {}, last_update {}, enabled {}, cltv_expiry_delta {}, htlc_minimum_msat {}, fee_base_msat {}, fee_proportional_millionths {}", log_pubkey!(self.src_node_id), self.last_update, self.enabled, self.cltv_expiry_delta, self.htlc_minimum_msat, self.fee_base_msat, self.fee_proportional_millionths)?;
  56                 Ok(())
  57         }
  58 }
  59
  60 struct ChannelInfo {
  61         features: GlobalFeatures,
  62         one_to_two: DirectionalChannelInfo,
  63         two_to_one: DirectionalChannelInfo,
  64 }
  65
  66 impl std::fmt::Display for ChannelInfo {
  67         fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
  68                 write!(f, "features: {}, one_to_two: {}, two_to_one: {}", log_bytes!(self.features.encode()), self.one_to_two, self.two_to_one)?;
  69                 Ok(())
  70         }
  71 }
  72
  73 struct NodeInfo {
  74         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
  75         channels: Vec<(u64, Sha256dHash)>,
  76         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
  77         channels: Vec<u64>,
  78
  79         lowest_inbound_channel_fee_base_msat: u32,
  80         lowest_inbound_channel_fee_proportional_millionths: u32,
  81
  82         features: GlobalFeatures,
  83         last_update: u32,
  84         rgb: [u8; 3],
  85         alias: [u8; 32],
  86         addresses: Vec<NetAddress>,
  87 }
  88
  89 impl std::fmt::Display for NodeInfo {
  90         fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
  91                 write!(f, "features: {}, last_update: {}, lowest_inbound_channel_fee_base_msat: {}, lowest_inbound_channel_fee_proportional_millionths: {}, channels: {:?}", log_bytes!(self.features.encode()), self.last_update, self.lowest_inbound_channel_fee_base_msat, self.lowest_inbound_channel_fee_proportional_millionths, &self.channels[..])?;
  92                 Ok(())
  93         }
  94 }
  95
  96 struct NetworkMap {
  97         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
  98         channels: HashMap<(u64, Sha256dHash), ChannelInfo>,
  99         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
 100         channels: HashMap<u64, ChannelInfo>,
 101
 102         our_node_id: PublicKey,
 103         nodes: HashMap<PublicKey, NodeInfo>,
 104 }
 105
 106 impl std::fmt::Display for NetworkMap {
 107         fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
 108                 write!(f, "Node id {} network map\n[Channels]\n", log_pubkey!(self.our_node_id))?;
 109                 for (key, val) in self.channels.iter() {
 110                         write!(f, " {}: {}\n", key, val)?;
 111                 }
 112                 write!(f, "[Nodes]\n")?;
 113                 for (key, val) in self.nodes.iter() {
 114                         write!(f, " {}: {}\n", log_pubkey!(key), val)?;
 115                 }
 116                 Ok(())
 117         }
 118 }
 119
 120 impl NetworkMap {
 121         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
 122         #[inline]
 123         fn get_key(short_channel_id: u64, chain_hash: Sha256dHash) -> (u64, Sha256dHash) {
 124                 (short_channel_id, chain_hash)
 125         }
 126
 127         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
 128         #[inline]
 129         fn get_key(short_channel_id: u64, _: Sha256dHash) -> u64 {
 130                 short_channel_id
 131         }
 132
 133         #[cfg(feature = "non_bitcoin_chain_hash_routing")]
 134         #[inline]
 135         fn get_short_id(id: &(u64, Sha256dHash)) -> &u64 {
 136                 &id.0
 137         }
 138
 139         #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
 140         #[inline]
 141         fn get_short_id(id: &u64) -> &u64 {
 142                 id
 143         }
 144 }
 145
 146 /// A channel descriptor which provides a last-hop route to get_route
 147 pub struct RouteHint {
 148         pub src_node_id: PublicKey,
 149         pub short_channel_id: u64,
 150         pub fee_base_msat: u32,
 151         pub fee_proportional_millionths: u32,
 152         pub cltv_expiry_delta: u16,
 153         pub htlc_minimum_msat: u64,
 154 }
 155
 156 /// Tracks a view of the network, receiving updates from peers and generating Routes to
 157 /// payment destinations.
 158 pub struct Router {
 159         secp_ctx: Secp256k1<secp256k1::VerifyOnly>,
 160         network_map: RwLock<NetworkMap>,
 161         chain_monitor: Arc<ChainWatchInterface>,
 162         logger: Arc<Logger>,
 163 }
 164
 165 macro_rules! secp_verify_sig {
 166         ( $secp_ctx: expr, $msg: expr, $sig: expr, $pubkey: expr ) => {
 167                 match $secp_ctx.verify($msg, $sig, $pubkey) {
 168                         Ok(_) => {},
 169                         Err(_) => return Err(HandleError{err: "Invalid signature from remote node", action: None}),
 170                 }
 171         };
 172 }
 173
 174 impl RoutingMessageHandler for Router {
 175         fn handle_node_announcement(&self, msg: &msgs::NodeAnnouncement) -> Result<bool, HandleError> {
 176                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 177                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &msg.contents.node_id);
 178
 179                 if msg.contents.features.requires_unknown_bits() {
 180                         panic!("Unknown-required-features NodeAnnouncements should never deserialize!");
 181                 }
 182
 183                 let mut network = self.network_map.write().unwrap();
 184                 match network.nodes.get_mut(&msg.contents.node_id) {
 185                         None => Err(HandleError{err: "No existing channels for node_announcement", action: Some(ErrorAction::IgnoreError)}),
 186                         Some(node) => {
 187                                 if node.last_update >= msg.contents.timestamp {
 188                                         return Err(HandleError{err: "Update older than last processed update", action: Some(ErrorAction::IgnoreError)});
 189                                 }
 190
 191                                 node.features = msg.contents.features.clone();
 192                                 node.last_update = msg.contents.timestamp;
 193                                 node.rgb = msg.contents.rgb;
 194                                 node.alias = msg.contents.alias;
 195                                 node.addresses = msg.contents.addresses.clone();
 196                                 Ok(msg.contents.excess_data.is_empty() && msg.contents.excess_address_data.is_empty() && !msg.contents.features.supports_unknown_bits())
 197                         }
 198                 }
 199         }
 200
 201         fn handle_channel_announcement(&self, msg: &msgs::ChannelAnnouncement) -> Result<bool, HandleError> {
 202                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 203                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
 204                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
 205                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
 206                 secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
 207
 208                 if msg.contents.features.requires_unknown_bits() {
 209                         panic!("Unknown-required-features ChannelAnnouncements should never deserialize!");
 210                 }
 211
 212                 match self.chain_monitor.get_chain_utxo(msg.contents.chain_hash, msg.contents.short_channel_id) {
 213                         Ok((script_pubkey, _value)) => {
 214                                 let expected_script = Builder::new().push_opcode(opcodes::All::OP_PUSHNUM_2)
 215                                                                     .push_slice(&msg.contents.bitcoin_key_1.serialize())
 216                                                                     .push_slice(&msg.contents.bitcoin_key_2.serialize())
 217                                                                     .push_opcode(opcodes::All::OP_PUSHNUM_2).push_opcode(opcodes::All::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
 218                                 if script_pubkey != expected_script {
 219                                         return Err(HandleError{err: "Channel announcement keys didn't match on-chain script", action: Some(ErrorAction::IgnoreError)});
 220                                 }
 221                                 //TODO: Check if value is worth storing, use it to inform routing, and compare it
 222                                 //to the new HTLC max field in channel_update
 223                         },
 224                         Err(ChainError::NotSupported) => {
 225                                 // Tentatively accept, potentially exposing us to DoS attacks
 226                         },
 227                         Err(ChainError::NotWatched) => {
 228                                 return Err(HandleError{err: "Channel announced on an unknown chain", action: Some(ErrorAction::IgnoreError)});
 229                         },
 230                         Err(ChainError::UnknownTx) => {
 231                                 return Err(HandleError{err: "Channel announced without corresponding UTXO entry", action: Some(ErrorAction::IgnoreError)});
 232                         },
 233                 }
 234
 235                 let mut network = self.network_map.write().unwrap();
 236
 237                 match network.channels.entry(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
 238                         Entry::Occupied(_) => {
 239                                 //TODO: because asking the blockchain if short_channel_id is valid is only optional
 240                                 //in the blockchain API, we need to handle it smartly here, though its unclear
 241                                 //exactly how...
 242                                 return Err(HandleError{err: "Already have knowledge of channel", action: Some(ErrorAction::IgnoreError)})
 243                         },
 244                         Entry::Vacant(entry) => {
 245                                 entry.insert(ChannelInfo {
 246                                         features: msg.contents.features.clone(),
 247                                         one_to_two: DirectionalChannelInfo {
 248                                                 src_node_id: msg.contents.node_id_1.clone(),
 249                                                 last_update: 0,
 250                                                 enabled: false,
 251                                                 cltv_expiry_delta: u16::max_value(),
 252                                                 htlc_minimum_msat: u64::max_value(),
 253                                                 fee_base_msat: u32::max_value(),
 254                                                 fee_proportional_millionths: u32::max_value(),
 255                                         },
 256                                         two_to_one: DirectionalChannelInfo {
 257                                                 src_node_id: msg.contents.node_id_2.clone(),
 258                                                 last_update: 0,
 259                                                 enabled: false,
 260                                                 cltv_expiry_delta: u16::max_value(),
 261                                                 htlc_minimum_msat: u64::max_value(),
 262                                                 fee_base_msat: u32::max_value(),
 263                                                 fee_proportional_millionths: u32::max_value(),
 264                                         }
 265                                 });
 266                         }
 267                 };
 268
 269                 macro_rules! add_channel_to_node {
 270                         ( $node_id: expr ) => {
 271                                 match network.nodes.entry($node_id) {
 272                                         Entry::Occupied(node_entry) => {
 273                                                 node_entry.into_mut().channels.push(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash));
 274                                         },
 275                                         Entry::Vacant(node_entry) => {
 276                                                 node_entry.insert(NodeInfo {
 277                                                         channels: vec!(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)),
 278                                                         lowest_inbound_channel_fee_base_msat: u32::max_value(),
 279                                                         lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
 280                                                         features: GlobalFeatures::new(),
 281                                                         last_update: 0,
 282                                                         rgb: [0; 3],
 283                                                         alias: [0; 32],
 284                                                         addresses: Vec::new(),
 285                                                 });
 286                                         }
 287                                 }
 288                         };
 289                 }
 290
 291                 add_channel_to_node!(msg.contents.node_id_1);
 292                 add_channel_to_node!(msg.contents.node_id_2);
 293
 294                 Ok(msg.contents.excess_data.is_empty() && !msg.contents.features.supports_unknown_bits())
 295         }
 296
 297         fn handle_htlc_fail_channel_update(&self, update: &msgs::HTLCFailChannelUpdate) {
 298                 match update {
 299                         &msgs::HTLCFailChannelUpdate::ChannelUpdateMessage { ref msg } => {
 300                                 let _ = self.handle_channel_update(msg);
 301                         },
 302                         &msgs::HTLCFailChannelUpdate::ChannelClosed { ref short_channel_id } => {
 303                                 let mut network = self.network_map.write().unwrap();
 304                                 if let Some(chan) = network.channels.remove(short_channel_id) {
 305                                         network.nodes.get_mut(&chan.one_to_two.src_node_id).unwrap().channels.retain(|chan_id| {
 306                                                 chan_id != NetworkMap::get_short_id(chan_id)
 307                                         });
 308                                         network.nodes.get_mut(&chan.two_to_one.src_node_id).unwrap().channels.retain(|chan_id| {
 309                                                 chan_id != NetworkMap::get_short_id(chan_id)
 310                                         });
 311                                 }
 312                         },
 313                 }
 314         }
 315
 316         fn handle_channel_update(&self, msg: &msgs::ChannelUpdate) -> Result<bool, HandleError> {
 317                 let mut network = self.network_map.write().unwrap();
 318                 let dest_node_id;
 319                 let chan_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
 320                 let chan_was_enabled;
 321
 322                 match network.channels.get_mut(&NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
 323                         None => return Err(HandleError{err: "Couldn't find channel for update", action: Some(ErrorAction::IgnoreError)}),
 324                         Some(channel) => {
 325                                 macro_rules! maybe_update_channel_info {
 326                                         ( $target: expr) => {
 327                                                 if $target.last_update >= msg.contents.timestamp {
 328                                                         return Err(HandleError{err: "Update older than last processed update", action: Some(ErrorAction::IgnoreError)});
 329                                                 }
 330                                                 chan_was_enabled = $target.enabled;
 331                                                 $target.last_update = msg.contents.timestamp;
 332                                                 $target.enabled = chan_enabled;
 333                                                 $target.cltv_expiry_delta = msg.contents.cltv_expiry_delta;
 334                                                 $target.htlc_minimum_msat = msg.contents.htlc_minimum_msat;
 335                                                 $target.fee_base_msat = msg.contents.fee_base_msat;
 336                                                 $target.fee_proportional_millionths = msg.contents.fee_proportional_millionths;
 337                                         }
 338                                 }
 339
 340                                 let msg_hash = Message::from_slice(&Sha256dHash::from_data(&msg.contents.encode()[..])[..]).unwrap();
 341                                 if msg.contents.flags & 1 == 1 {
 342                                         dest_node_id = channel.one_to_two.src_node_id.clone();
 343                                         secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.two_to_one.src_node_id);
 344                                         maybe_update_channel_info!(channel.two_to_one);
 345                                 } else {
 346                                         dest_node_id = channel.two_to_one.src_node_id.clone();
 347                                         secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.one_to_two.src_node_id);
 348                                         maybe_update_channel_info!(channel.one_to_two);
 349                                 }
 350                         }
 351                 }
 352
 353                 if chan_enabled {
 354                         let node = network.nodes.get_mut(&dest_node_id).unwrap();
 355                         node.lowest_inbound_channel_fee_base_msat = cmp::min(node.lowest_inbound_channel_fee_base_msat, msg.contents.fee_base_msat);
 356                         node.lowest_inbound_channel_fee_proportional_millionths = cmp::min(node.lowest_inbound_channel_fee_proportional_millionths, msg.contents.fee_proportional_millionths);
 357                 } else if chan_was_enabled {
 358                         let mut lowest_inbound_channel_fee_base_msat = u32::max_value();
 359                         let mut lowest_inbound_channel_fee_proportional_millionths = u32::max_value();
 360
 361                         {
 362                                 let node = network.nodes.get(&dest_node_id).unwrap();
 363
 364                                 for chan_id in node.channels.iter() {
 365                                         let chan = network.channels.get(chan_id).unwrap();
 366                                         if chan.one_to_two.src_node_id == dest_node_id {
 367                                                 lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.two_to_one.fee_base_msat);
 368                                                 lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.two_to_one.fee_proportional_millionths);
 369                                         } else {
 370                                                 lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.one_to_two.fee_base_msat);
 371                                                 lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.one_to_two.fee_proportional_millionths);
 372                                         }
 373                                 }
 374                         }
 375
 376                         //TODO: satisfy the borrow-checker without a double-map-lookup :(
 377                         let mut_node = network.nodes.get_mut(&dest_node_id).unwrap();
 378                         mut_node.lowest_inbound_channel_fee_base_msat = lowest_inbound_channel_fee_base_msat;
 379                         mut_node.lowest_inbound_channel_fee_proportional_millionths = lowest_inbound_channel_fee_proportional_millionths;
 380                 }
 381
 382                 Ok(msg.contents.excess_data.is_empty())
 383         }
 384 }
 385
 386 #[derive(Eq, PartialEq)]
 387 struct RouteGraphNode {
 388         pubkey: PublicKey,
 389         lowest_fee_to_peer_through_node: u64,
 390         lowest_fee_to_node: u64,
 391 }
 392
 393 impl cmp::Ord for RouteGraphNode {
 394         fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
 395                 other.lowest_fee_to_peer_through_node.cmp(&self.lowest_fee_to_peer_through_node)
 396                         .then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize()))
 397         }
 398 }
 399
 400 impl cmp::PartialOrd for RouteGraphNode {
 401         fn partial_cmp(&self, other: &RouteGraphNode) -> Option<cmp::Ordering> {
 402                 Some(self.cmp(other))
 403         }
 404 }
 405
 406 struct DummyDirectionalChannelInfo {
 407         src_node_id: PublicKey,
 408         cltv_expiry_delta: u32,
 409         htlc_minimum_msat: u64,
 410         fee_base_msat: u32,
 411         fee_proportional_millionths: u32,
 412 }
 413
 414 impl Router {
 415         pub fn new(our_pubkey: PublicKey, chain_monitor: Arc<ChainWatchInterface>, logger: Arc<Logger>) -> Router {
 416                 let mut nodes = HashMap::new();
 417                 nodes.insert(our_pubkey.clone(), NodeInfo {
 418                         channels: Vec::new(),
 419                         lowest_inbound_channel_fee_base_msat: u32::max_value(),
 420                         lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
 421                         features: GlobalFeatures::new(),
 422                         last_update: 0,
 423                         rgb: [0; 3],
 424                         alias: [0; 32],
 425                         addresses: Vec::new(),
 426                 });
 427                 Router {
 428                         secp_ctx: Secp256k1::verification_only(),
 429                         network_map: RwLock::new(NetworkMap {
 430                                 channels: HashMap::new(),
 431                                 our_node_id: our_pubkey,
 432                                 nodes: nodes,
 433                         }),
 434                         chain_monitor,
 435                         logger,
 436                 }
 437         }
 438
 439         /// Dumps the entire network view of this Router to the logger provided in the constructor at
 440         /// level Trace
 441         pub fn trace_state(&self) {
 442                 log_trace!(self, "{}", self.network_map.read().unwrap());
 443         }
 444
 445         /// Get network addresses by node id
 446         pub fn get_addresses(&self, pubkey: &PublicKey) -> Option<Vec<NetAddress>> {
 447                 let network = self.network_map.read().unwrap();
 448                 network.nodes.get(pubkey).map(|n| n.addresses.clone())
 449         }
 450
 451         /// Marks a node as having failed a route. This will avoid re-using the node in routes for now,
 452         /// with an expotnential decay in node "badness". Note that there is deliberately no
 453         /// mark_channel_bad as a node may simply lie and suggest that an upstream channel from it is
 454         /// what failed the route and not the node itself. Instead, setting the blamed_upstream_node
 455         /// boolean will reduce the penalty, returning the node to usability faster. If the node is
 456         /// behaving correctly, it will disable the failing channel and we will use it again next time.
 457         pub fn mark_node_bad(&self, _node_id: &PublicKey, _blamed_upstream_node: bool) {
 458                 unimplemented!();
 459         }
 460
 461         /// Gets a route from us to the given target node.
 462         /// Extra routing hops between known nodes and the target will be used if they are included in
 463         /// last_hops.
 464         /// If some channels aren't announced, it may be useful to fill in a first_hops with the
 465         /// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our
 466         /// (this Router's) view of our local channels will be ignored, and only those in first_hops
 467         /// will be used. Panics if first_hops contains channels without short_channel_ids
 468         /// (ChannelManager::list_usable_channels will never include such channels).
 469         /// The fees on channels from us to next-hops are ignored (as they are assumed to all be
 470         /// equal), however the enabled/disabled bit on such channels as well as the htlc_minimum_msat
 471         /// *is* checked as they may change based on the receiving node.
 472         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> {
 473                 // TODO: Obviously *only* using total fee cost sucks. We should consider weighting by
 474                 // uptime/success in using a node in the past.
 475                 let network = self.network_map.read().unwrap();
 476
 477                 if *target == network.our_node_id {
 478                         return Err(HandleError{err: "Cannot generate a route to ourselves", action: None});
 479                 }
 480
 481                 if final_value_msat > 21_000_000 * 1_0000_0000 * 1000 {
 482                         return Err(HandleError{err: "Cannot generate a route of more value than all existing satoshis", action: None});
 483                 }
 484
 485                 // We do a dest-to-source Dijkstra's sorting by each node's distance from the destination
 486                 // plus the minimum per-HTLC fee to get from it to another node (aka "shitty A*").
 487                 // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff
 488                 // to use as the A* heuristic beyond just the cost to get one node further than the current
 489                 // one.
 490
 491                 let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes
 492                         src_node_id: network.our_node_id.clone(),
 493                         cltv_expiry_delta: 0,
 494                         htlc_minimum_msat: 0,
 495                         fee_base_msat: 0,
 496                         fee_proportional_millionths: 0,
 497                 };
 498
 499                 let mut targets = BinaryHeap::new(); //TODO: Do we care about switching to eg Fibbonaci heap?
 500                 let mut dist = HashMap::with_capacity(network.nodes.len());
 501
 502                 let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
 503                 if let Some(hops) = first_hops {
 504                         for chan in hops {
 505                                 let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
 506                                 if chan.remote_network_id == *target {
 507                                         return Ok(Route {
 508                                                 hops: vec![RouteHop {
 509                                                         pubkey: chan.remote_network_id,
 510                                                         short_channel_id,
 511                                                         fee_msat: final_value_msat,
 512                                                         cltv_expiry_delta: final_cltv,
 513                                                 }],
 514                                         });
 515                                 }
 516                                 first_hop_targets.insert(chan.remote_network_id, short_channel_id);
 517                         }
 518                         if first_hop_targets.is_empty() {
 519                                 return Err(HandleError{err: "Cannot route when there are no outbound routes away from us", action: None});
 520                         }
 521                 }
 522
 523                 macro_rules! add_entry {
 524                         // Adds entry which goes from the node pointed to by $directional_info to
 525                         // $dest_node_id over the channel with id $chan_id with fees described in
 526                         // $directional_info.
 527                         ( $chan_id: expr, $dest_node_id: expr, $directional_info: expr, $starting_fee_msat: expr ) => {
 528                                 //TODO: Explore simply adding fee to hit htlc_minimum_msat
 529                                 if $starting_fee_msat as u64 + final_value_msat > $directional_info.htlc_minimum_msat {
 530                                         let proportional_fee_millions = ($starting_fee_msat + final_value_msat).checked_mul($directional_info.fee_proportional_millionths as u64);
 531                                         if let Some(new_fee) = proportional_fee_millions.and_then(|part| {
 532                                                         ($directional_info.fee_base_msat as u64).checked_add(part / 1000000) })
 533                                         {
 534                                                 let mut total_fee = $starting_fee_msat as u64;
 535                                                 let hm_entry = dist.entry(&$directional_info.src_node_id);
 536                                                 let old_entry = hm_entry.or_insert_with(|| {
 537                                                         let node = network.nodes.get(&$directional_info.src_node_id).unwrap();
 538                                                         (u64::max_value(),
 539                                                                 node.lowest_inbound_channel_fee_base_msat,
 540                                                                 node.lowest_inbound_channel_fee_proportional_millionths,
 541                                                                 RouteHop {
 542                                                                         pubkey: $dest_node_id.clone(),
 543                                                                         short_channel_id: 0,
 544                                                                         fee_msat: 0,
 545                                                                         cltv_expiry_delta: 0,
 546                                                         })
 547                                                 });
 548                                                 if $directional_info.src_node_id != network.our_node_id {
 549                                                         // Ignore new_fee for channel-from-us as we assume all channels-from-us
 550                                                         // will have the same effective-fee
 551                                                         total_fee += new_fee;
 552                                                         if let Some(fee_inc) = final_value_msat.checked_add(total_fee).and_then(|inc| { (old_entry.2 as u64).checked_mul(inc) }) {
 553                                                                 total_fee += fee_inc / 1000000 + (old_entry.1 as u64);
 554                                                         } else {
 555                                                                 // max_value means we'll always fail the old_entry.0 > total_fee check
 556                                                                 total_fee = u64::max_value();
 557                                                         }
 558                                                 }
 559                                                 let new_graph_node = RouteGraphNode {
 560                                                         pubkey: $directional_info.src_node_id,
 561                                                         lowest_fee_to_peer_through_node: total_fee,
 562                                                         lowest_fee_to_node: $starting_fee_msat as u64 + new_fee,
 563                                                 };
 564                                                 if old_entry.0 > total_fee {
 565                                                         targets.push(new_graph_node);
 566                                                         old_entry.0 = total_fee;
 567                                                         old_entry.3 = RouteHop {
 568                                                                 pubkey: $dest_node_id.clone(),
 569                                                                 short_channel_id: $chan_id.clone(),
 570                                                                 fee_msat: new_fee, // This field is ignored on the last-hop anyway
 571                                                                 cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32,
 572                                                         }
 573                                                 }
 574                                         }
 575                                 }
 576                         };
 577                 }
 578
 579                 macro_rules! add_entries_to_cheapest_to_target_node {
 580                         ( $node: expr, $node_id: expr, $fee_to_target_msat: expr ) => {
 581                                 if first_hops.is_some() {
 582                                         if let Some(first_hop) = first_hop_targets.get(&$node_id) {
 583                                                 add_entry!(first_hop, $node_id, dummy_directional_info, $fee_to_target_msat);
 584                                         }
 585                                 }
 586
 587                                 for chan_id in $node.channels.iter() {
 588                                         let chan = network.channels.get(chan_id).unwrap();
 589                                         if chan.one_to_two.src_node_id == *$node_id {
 590                                                 // ie $node is one, ie next hop in A* is two, via the two_to_one channel
 591                                                 if first_hops.is_none() || chan.two_to_one.src_node_id != network.our_node_id {
 592                                                         if chan.two_to_one.enabled {
 593                                                                 add_entry!(chan_id, chan.one_to_two.src_node_id, chan.two_to_one, $fee_to_target_msat);
 594                                                         }
 595                                                 }
 596                                         } else {
 597                                                 if first_hops.is_none() || chan.one_to_two.src_node_id != network.our_node_id {
 598                                                         if chan.one_to_two.enabled {
 599                                                                 add_entry!(chan_id, chan.two_to_one.src_node_id, chan.one_to_two, $fee_to_target_msat);
 600                                                         }
 601                                                 }
 602                                         }
 603                                 }
 604                         };
 605                 }
 606
 607                 match network.nodes.get(target) {
 608                         None => {},
 609                         Some(node) => {
 610                                 add_entries_to_cheapest_to_target_node!(node, target, 0);
 611                         },
 612                 }
 613
 614                 for hop in last_hops.iter() {
 615                         if first_hops.is_none() || hop.src_node_id != network.our_node_id { // first_hop overrules last_hops
 616                                 if network.nodes.get(&hop.src_node_id).is_some() {
 617                                         if first_hops.is_some() {
 618                                                 if let Some(first_hop) = first_hop_targets.get(&hop.src_node_id) {
 619                                                         add_entry!(first_hop, hop.src_node_id, dummy_directional_info, 0);
 620                                                 }
 621                                         }
 622                                         add_entry!(hop.short_channel_id, target, hop, 0);
 623                                 }
 624                         }
 625                 }
 626
 627                 while let Some(RouteGraphNode { pubkey, lowest_fee_to_node, .. }) = targets.pop() {
 628                         if pubkey == network.our_node_id {
 629                                 let mut res = vec!(dist.remove(&network.our_node_id).unwrap().3);
 630                                 while res.last().unwrap().pubkey != *target {
 631                                         let new_entry = match dist.remove(&res.last().unwrap().pubkey) {
 632                                                 Some(hop) => hop.3,
 633                                                 None => return Err(HandleError{err: "Failed to find a non-fee-overflowing path to the given destination", action: None}),
 634                                         };
 635                                         res.last_mut().unwrap().fee_msat = new_entry.fee_msat;
 636                                         res.last_mut().unwrap().cltv_expiry_delta = new_entry.cltv_expiry_delta;
 637                                         res.push(new_entry);
 638                                 }
 639                                 res.last_mut().unwrap().fee_msat = final_value_msat;
 640                                 res.last_mut().unwrap().cltv_expiry_delta = final_cltv;
 641                                 let route = Route { hops: res };
 642                                 log_trace!(self, "Got route: {}", log_route!(route));
 643                                 return Ok(route);
 644                         }
 645
 646                         match network.nodes.get(&pubkey) {
 647                                 None => {},
 648                                 Some(node) => {
 649                                         add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node);
 650                                 },
 651                         }
 652                 }
 653
 654                 Err(HandleError{err: "Failed to find a path to the given destination", action: None})
 655         }
 656 }
 657
 658 #[cfg(test)]
 659 mod tests {
 660         use chain::chaininterface;
 661         use ln::channelmanager;
 662         use ln::router::{Router,NodeInfo,NetworkMap,ChannelInfo,DirectionalChannelInfo,RouteHint};
 663         use ln::msgs::GlobalFeatures;
 664         use util::test_utils;
 665         use util::logger::Logger;
 666
 667         use bitcoin::util::hash::Sha256dHash;
 668         use bitcoin::network::constants::Network;
 669
 670         use hex;
 671
 672         use secp256k1::key::{PublicKey,SecretKey};
 673         use secp256k1::Secp256k1;
 674
 675         use std::sync::Arc;
 676
 677         #[test]
 678         fn route_test() {
 679                 let secp_ctx = Secp256k1::new();
 680                 let our_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap());
 681                 let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());
 682                 let chain_monitor = Arc::new(chaininterface::ChainWatchInterfaceUtil::new(Network::Testnet, Arc::clone(&logger)));
 683                 let router = Router::new(our_id, chain_monitor, Arc::clone(&logger));
 684
 685                 // Build network from our_id to node8:
 686                 //
 687                 //        -1(1)2-  node1  -1(3)2-
 688                 //       /                       \
 689                 // our_id -1(12)2- node8 -1(13)2--- node3
 690                 //       \                       /
 691                 //        -1(2)2-  node2  -1(4)2-
 692                 //
 693                 //
 694                 // chan1  1-to-2: disabled
 695                 // chan1  2-to-1: enabled, 0 fee
 696                 //
 697                 // chan2  1-to-2: enabled, ignored fee
 698                 // chan2  2-to-1: enabled, 0 fee
 699                 //
 700                 // chan3  1-to-2: enabled, 0 fee
 701                 // chan3  2-to-1: enabled, 100 msat fee
 702                 //
 703                 // chan4  1-to-2: enabled, 100% fee
 704                 // chan4  2-to-1: enabled, 0 fee
 705                 //
 706                 // chan12 1-to-2: enabled, ignored fee
 707                 // chan12 2-to-1: enabled, 0 fee
 708                 //
 709                 // chan13 1-to-2: enabled, 200% fee
 710                 // chan13 2-to-1: enabled, 0 fee
 711                 //
 712                 //
 713                 //       -1(5)2- node4 -1(8)2--
 714                 //       |         2          |
 715                 //       |       (11)         |
 716                 //      /          1           \
 717                 // node3--1(6)2- node5 -1(9)2--- node7 (not in global route map)
 718                 //      \                      /
 719                 //       -1(7)2- node6 -1(10)2-
 720                 //
 721                 // chan5  1-to-2: enabled, 100 msat fee
 722                 // chan5  2-to-1: enabled, 0 fee
 723                 //
 724                 // chan6  1-to-2: enabled, 0 fee
 725                 // chan6  2-to-1: enabled, 0 fee
 726                 //
 727                 // chan7  1-to-2: enabled, 100% fee
 728                 // chan7  2-to-1: enabled, 0 fee
 729                 //
 730                 // chan8  1-to-2: enabled, variable fee (0 then 1000 msat)
 731                 // chan8  2-to-1: enabled, 0 fee
 732                 //
 733                 // chan9  1-to-2: enabled, 1001 msat fee
 734                 // chan9  2-to-1: enabled, 0 fee
 735                 //
 736                 // chan10 1-to-2: enabled, 0 fee
 737                 // chan10 2-to-1: enabled, 0 fee
 738                 //
 739                 // chan11 1-to-2: enabled, 0 fee
 740                 // chan11 2-to-1: enabled, 0 fee
 741
 742                 let node1 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap());
 743                 let node2 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0303030303030303030303030303030303030303030303030303030303030303").unwrap()[..]).unwrap());
 744                 let node3 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0404040404040404040404040404040404040404040404040404040404040404").unwrap()[..]).unwrap());
 745                 let node4 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0505050505050505050505050505050505050505050505050505050505050505").unwrap()[..]).unwrap());
 746                 let node5 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0606060606060606060606060606060606060606060606060606060606060606").unwrap()[..]).unwrap());
 747                 let node6 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0707070707070707070707070707070707070707070707070707070707070707").unwrap()[..]).unwrap());
 748                 let node7 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0808080808080808080808080808080808080808080808080808080808080808").unwrap()[..]).unwrap());
 749                 let node8 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&secp_ctx, &hex::decode("0909090909090909090909090909090909090909090909090909090909090909").unwrap()[..]).unwrap());
 750
 751                 let zero_hash = Sha256dHash::from_data(&[0; 32]);
 752
 753                 {
 754                         let mut network = router.network_map.write().unwrap();
 755
 756                         network.nodes.insert(node1.clone(), NodeInfo {
 757                                 channels: vec!(NetworkMap::get_key(1, zero_hash.clone()), NetworkMap::get_key(3, zero_hash.clone())),
 758                                 lowest_inbound_channel_fee_base_msat: 100,
 759                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 760                                 features: GlobalFeatures::new(),
 761                                 last_update: 1,
 762                                 rgb: [0; 3],
 763                                 alias: [0; 32],
 764                                 addresses: Vec::new(),
 765                         });
 766                         network.channels.insert(NetworkMap::get_key(1, zero_hash.clone()), ChannelInfo {
 767                                 features: GlobalFeatures::new(),
 768                                 one_to_two: DirectionalChannelInfo {
 769                                         src_node_id: our_id.clone(),
 770                                         last_update: 0,
 771                                         enabled: false,
 772                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 773                                         htlc_minimum_msat: 0,
 774                                         fee_base_msat: u32::max_value(), // This value should be ignored
 775                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 776                                 }, two_to_one: DirectionalChannelInfo {
 777                                         src_node_id: node1.clone(),
 778                                         last_update: 0,
 779                                         enabled: true,
 780                                         cltv_expiry_delta: 0,
 781                                         htlc_minimum_msat: 0,
 782                                         fee_base_msat: 0,
 783                                         fee_proportional_millionths: 0,
 784                                 },
 785                         });
 786                         network.nodes.insert(node2.clone(), NodeInfo {
 787                                 channels: vec!(NetworkMap::get_key(2, zero_hash.clone()), NetworkMap::get_key(4, zero_hash.clone())),
 788                                 lowest_inbound_channel_fee_base_msat: 0,
 789                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 790                                 features: GlobalFeatures::new(),
 791                                 last_update: 1,
 792                                 rgb: [0; 3],
 793                                 alias: [0; 32],
 794                                 addresses: Vec::new(),
 795                         });
 796                         network.channels.insert(NetworkMap::get_key(2, zero_hash.clone()), ChannelInfo {
 797                                 features: GlobalFeatures::new(),
 798                                 one_to_two: DirectionalChannelInfo {
 799                                         src_node_id: our_id.clone(),
 800                                         last_update: 0,
 801                                         enabled: true,
 802                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 803                                         htlc_minimum_msat: 0,
 804                                         fee_base_msat: u32::max_value(), // This value should be ignored
 805                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 806                                 }, two_to_one: DirectionalChannelInfo {
 807                                         src_node_id: node2.clone(),
 808                                         last_update: 0,
 809                                         enabled: true,
 810                                         cltv_expiry_delta: 0,
 811                                         htlc_minimum_msat: 0,
 812                                         fee_base_msat: 0,
 813                                         fee_proportional_millionths: 0,
 814                                 },
 815                         });
 816                         network.nodes.insert(node8.clone(), NodeInfo {
 817                                 channels: vec!(NetworkMap::get_key(12, zero_hash.clone()), NetworkMap::get_key(13, zero_hash.clone())),
 818                                 lowest_inbound_channel_fee_base_msat: 0,
 819                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 820                                 features: GlobalFeatures::new(),
 821                                 last_update: 1,
 822                                 rgb: [0; 3],
 823                                 alias: [0; 32],
 824                                 addresses: Vec::new(),
 825                         });
 826                         network.channels.insert(NetworkMap::get_key(12, zero_hash.clone()), ChannelInfo {
 827                                 features: GlobalFeatures::new(),
 828                                 one_to_two: DirectionalChannelInfo {
 829                                         src_node_id: our_id.clone(),
 830                                         last_update: 0,
 831                                         enabled: true,
 832                                         cltv_expiry_delta: u16::max_value(), // This value should be ignored
 833                                         htlc_minimum_msat: 0,
 834                                         fee_base_msat: u32::max_value(), // This value should be ignored
 835                                         fee_proportional_millionths: u32::max_value(), // This value should be ignored
 836                                 }, two_to_one: DirectionalChannelInfo {
 837                                         src_node_id: node8.clone(),
 838                                         last_update: 0,
 839                                         enabled: true,
 840                                         cltv_expiry_delta: 0,
 841                                         htlc_minimum_msat: 0,
 842                                         fee_base_msat: 0,
 843                                         fee_proportional_millionths: 0,
 844                                 },
 845                         });
 846                         network.nodes.insert(node3.clone(), NodeInfo {
 847                                 channels: vec!(
 848                                         NetworkMap::get_key(3, zero_hash.clone()),
 849                                         NetworkMap::get_key(4, zero_hash.clone()),
 850                                         NetworkMap::get_key(13, zero_hash.clone()),
 851                                         NetworkMap::get_key(5, zero_hash.clone()),
 852                                         NetworkMap::get_key(6, zero_hash.clone()),
 853                                         NetworkMap::get_key(7, zero_hash.clone())),
 854                                 lowest_inbound_channel_fee_base_msat: 0,
 855                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 856                                 features: GlobalFeatures::new(),
 857                                 last_update: 1,
 858                                 rgb: [0; 3],
 859                                 alias: [0; 32],
 860                                 addresses: Vec::new(),
 861                         });
 862                         network.channels.insert(NetworkMap::get_key(3, zero_hash.clone()), ChannelInfo {
 863                                 features: GlobalFeatures::new(),
 864                                 one_to_two: DirectionalChannelInfo {
 865                                         src_node_id: node1.clone(),
 866                                         last_update: 0,
 867                                         enabled: true,
 868                                         cltv_expiry_delta: (3 << 8) | 1,
 869                                         htlc_minimum_msat: 0,
 870                                         fee_base_msat: 0,
 871                                         fee_proportional_millionths: 0,
 872                                 }, two_to_one: DirectionalChannelInfo {
 873                                         src_node_id: node3.clone(),
 874                                         last_update: 0,
 875                                         enabled: true,
 876                                         cltv_expiry_delta: (3 << 8) | 2,
 877                                         htlc_minimum_msat: 0,
 878                                         fee_base_msat: 100,
 879                                         fee_proportional_millionths: 0,
 880                                 },
 881                         });
 882                         network.channels.insert(NetworkMap::get_key(4, zero_hash.clone()), ChannelInfo {
 883                                 features: GlobalFeatures::new(),
 884                                 one_to_two: DirectionalChannelInfo {
 885                                         src_node_id: node2.clone(),
 886                                         last_update: 0,
 887                                         enabled: true,
 888                                         cltv_expiry_delta: (4 << 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: node3.clone(),
 894                                         last_update: 0,
 895                                         enabled: true,
 896                                         cltv_expiry_delta: (4 << 8) | 2,
 897                                         htlc_minimum_msat: 0,
 898                                         fee_base_msat: 0,
 899                                         fee_proportional_millionths: 0,
 900                                 },
 901                         });
 902                         network.channels.insert(NetworkMap::get_key(13, zero_hash.clone()), ChannelInfo {
 903                                 features: GlobalFeatures::new(),
 904                                 one_to_two: DirectionalChannelInfo {
 905                                         src_node_id: node8.clone(),
 906                                         last_update: 0,
 907                                         enabled: true,
 908                                         cltv_expiry_delta: (13 << 8) | 1,
 909                                         htlc_minimum_msat: 0,
 910                                         fee_base_msat: 0,
 911                                         fee_proportional_millionths: 2000000,
 912                                 }, two_to_one: DirectionalChannelInfo {
 913                                         src_node_id: node3.clone(),
 914                                         last_update: 0,
 915                                         enabled: true,
 916                                         cltv_expiry_delta: (13 << 8) | 2,
 917                                         htlc_minimum_msat: 0,
 918                                         fee_base_msat: 0,
 919                                         fee_proportional_millionths: 0,
 920                                 },
 921                         });
 922                         network.nodes.insert(node4.clone(), NodeInfo {
 923                                 channels: vec!(NetworkMap::get_key(5, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 924                                 lowest_inbound_channel_fee_base_msat: 0,
 925                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 926                                 features: GlobalFeatures::new(),
 927                                 last_update: 1,
 928                                 rgb: [0; 3],
 929                                 alias: [0; 32],
 930                                 addresses: Vec::new(),
 931                         });
 932                         network.channels.insert(NetworkMap::get_key(5, zero_hash.clone()), ChannelInfo {
 933                                 features: GlobalFeatures::new(),
 934                                 one_to_two: DirectionalChannelInfo {
 935                                         src_node_id: node3.clone(),
 936                                         last_update: 0,
 937                                         enabled: true,
 938                                         cltv_expiry_delta: (5 << 8) | 1,
 939                                         htlc_minimum_msat: 0,
 940                                         fee_base_msat: 100,
 941                                         fee_proportional_millionths: 0,
 942                                 }, two_to_one: DirectionalChannelInfo {
 943                                         src_node_id: node4.clone(),
 944                                         last_update: 0,
 945                                         enabled: true,
 946                                         cltv_expiry_delta: (5 << 8) | 2,
 947                                         htlc_minimum_msat: 0,
 948                                         fee_base_msat: 0,
 949                                         fee_proportional_millionths: 0,
 950                                 },
 951                         });
 952                         network.nodes.insert(node5.clone(), NodeInfo {
 953                                 channels: vec!(NetworkMap::get_key(6, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
 954                                 lowest_inbound_channel_fee_base_msat: 0,
 955                                 lowest_inbound_channel_fee_proportional_millionths: 0,
 956                                 features: GlobalFeatures::new(),
 957                                 last_update: 1,
 958                                 rgb: [0; 3],
 959                                 alias: [0; 32],
 960                                 addresses: Vec::new(),
 961                         });
 962                         network.channels.insert(NetworkMap::get_key(6, zero_hash.clone()), ChannelInfo {
 963                                 features: GlobalFeatures::new(),
 964                                 one_to_two: DirectionalChannelInfo {
 965                                         src_node_id: node3.clone(),
 966                                         last_update: 0,
 967                                         enabled: true,
 968                                         cltv_expiry_delta: (6 << 8) | 1,
 969                                         htlc_minimum_msat: 0,
 970                                         fee_base_msat: 0,
 971                                         fee_proportional_millionths: 0,
 972                                 }, two_to_one: DirectionalChannelInfo {
 973                                         src_node_id: node5.clone(),
 974                                         last_update: 0,
 975                                         enabled: true,
 976                                         cltv_expiry_delta: (6 << 8) | 2,
 977                                         htlc_minimum_msat: 0,
 978                                         fee_base_msat: 0,
 979                                         fee_proportional_millionths: 0,
 980                                 },
 981                         });
 982                         network.channels.insert(NetworkMap::get_key(11, zero_hash.clone()), ChannelInfo {
 983                                 features: GlobalFeatures::new(),
 984                                 one_to_two: DirectionalChannelInfo {
 985                                         src_node_id: node5.clone(),
 986                                         last_update: 0,
 987                                         enabled: true,
 988                                         cltv_expiry_delta: (11 << 8) | 1,
 989                                         htlc_minimum_msat: 0,
 990                                         fee_base_msat: 0,
 991                                         fee_proportional_millionths: 0,
 992                                 }, two_to_one: DirectionalChannelInfo {
 993                                         src_node_id: node4.clone(),
 994                                         last_update: 0,
 995                                         enabled: true,
 996                                         cltv_expiry_delta: (11 << 8) | 2,
 997                                         htlc_minimum_msat: 0,
 998                                         fee_base_msat: 0,
 999                                         fee_proportional_millionths: 0,
1000                                 },
1001                         });
1002                         network.nodes.insert(node6.clone(), NodeInfo {
1003                                 channels: vec!(NetworkMap::get_key(7, zero_hash.clone())),
1004                                 lowest_inbound_channel_fee_base_msat: 0,
1005                                 lowest_inbound_channel_fee_proportional_millionths: 0,
1006                                 features: GlobalFeatures::new(),
1007                                 last_update: 1,
1008                                 rgb: [0; 3],
1009                                 alias: [0; 32],
1010                                 addresses: Vec::new(),
1011                         });
1012                         network.channels.insert(NetworkMap::get_key(7, zero_hash.clone()), ChannelInfo {
1013                                 features: GlobalFeatures::new(),
1014                                 one_to_two: DirectionalChannelInfo {
1015                                         src_node_id: node3.clone(),
1016                                         last_update: 0,
1017                                         enabled: true,
1018                                         cltv_expiry_delta: (7 << 8) | 1,
1019                                         htlc_minimum_msat: 0,
1020                                         fee_base_msat: 0,
1021                                         fee_proportional_millionths: 1000000,
1022                                 }, two_to_one: DirectionalChannelInfo {
1023                                         src_node_id: node6.clone(),
1024                                         last_update: 0,
1025                                         enabled: true,
1026                                         cltv_expiry_delta: (7 << 8) | 2,
1027                                         htlc_minimum_msat: 0,
1028                                         fee_base_msat: 0,
1029                                         fee_proportional_millionths: 0,
1030                                 },
1031                         });
1032                 }
1033
1034                 { // Simple route to 3 via 2
1035                         let route = router.get_route(&node3, None, &Vec::new(), 100, 42).unwrap();
1036                         assert_eq!(route.hops.len(), 2);
1037
1038                         assert_eq!(route.hops[0].pubkey, node2);
1039                         assert_eq!(route.hops[0].short_channel_id, 2);
1040                         assert_eq!(route.hops[0].fee_msat, 100);
1041                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1042
1043                         assert_eq!(route.hops[1].pubkey, node3);
1044                         assert_eq!(route.hops[1].short_channel_id, 4);
1045                         assert_eq!(route.hops[1].fee_msat, 100);
1046                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
1047                 }
1048
1049                 { // Route to 1 via 2 and 3 because our channel to 1 is disabled
1050                         let route = router.get_route(&node1, None, &Vec::new(), 100, 42).unwrap();
1051                         assert_eq!(route.hops.len(), 3);
1052
1053                         assert_eq!(route.hops[0].pubkey, node2);
1054                         assert_eq!(route.hops[0].short_channel_id, 2);
1055                         assert_eq!(route.hops[0].fee_msat, 200);
1056                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1057
1058                         assert_eq!(route.hops[1].pubkey, node3);
1059                         assert_eq!(route.hops[1].short_channel_id, 4);
1060                         assert_eq!(route.hops[1].fee_msat, 100);
1061                         assert_eq!(route.hops[1].cltv_expiry_delta, (3 << 8) | 2);
1062
1063                         assert_eq!(route.hops[2].pubkey, node1);
1064                         assert_eq!(route.hops[2].short_channel_id, 3);
1065                         assert_eq!(route.hops[2].fee_msat, 100);
1066                         assert_eq!(route.hops[2].cltv_expiry_delta, 42);
1067                 }
1068
1069                 { // If we specify a channel to node8, that overrides our local channel view and that gets used
1070                         let our_chans = vec![channelmanager::ChannelDetails {
1071                                 channel_id: [0; 32],
1072                                 short_channel_id: Some(42),
1073                                 remote_network_id: node8.clone(),
1074                                 channel_value_satoshis: 0,
1075                                 user_id: 0,
1076                         }];
1077                         let route = router.get_route(&node3, Some(&our_chans), &Vec::new(), 100, 42).unwrap();
1078                         assert_eq!(route.hops.len(), 2);
1079
1080                         assert_eq!(route.hops[0].pubkey, node8);
1081                         assert_eq!(route.hops[0].short_channel_id, 42);
1082                         assert_eq!(route.hops[0].fee_msat, 200);
1083                         assert_eq!(route.hops[0].cltv_expiry_delta, (13 << 8) | 1);
1084
1085                         assert_eq!(route.hops[1].pubkey, node3);
1086                         assert_eq!(route.hops[1].short_channel_id, 13);
1087                         assert_eq!(route.hops[1].fee_msat, 100);
1088                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
1089                 }
1090
1091                 let mut last_hops = vec!(RouteHint {
1092                                 src_node_id: node4.clone(),
1093                                 short_channel_id: 8,
1094                                 fee_base_msat: 0,
1095                                 fee_proportional_millionths: 0,
1096                                 cltv_expiry_delta: (8 << 8) | 1,
1097                                 htlc_minimum_msat: 0,
1098                         }, RouteHint {
1099                                 src_node_id: node5.clone(),
1100                                 short_channel_id: 9,
1101                                 fee_base_msat: 1001,
1102                                 fee_proportional_millionths: 0,
1103                                 cltv_expiry_delta: (9 << 8) | 1,
1104                                 htlc_minimum_msat: 0,
1105                         }, RouteHint {
1106                                 src_node_id: node6.clone(),
1107                                 short_channel_id: 10,
1108                                 fee_base_msat: 0,
1109                                 fee_proportional_millionths: 0,
1110                                 cltv_expiry_delta: (10 << 8) | 1,
1111                                 htlc_minimum_msat: 0,
1112                         });
1113
1114                 { // Simple test across 2, 3, 5, and 4 via a last_hop channel
1115                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
1116                         assert_eq!(route.hops.len(), 5);
1117
1118                         assert_eq!(route.hops[0].pubkey, node2);
1119                         assert_eq!(route.hops[0].short_channel_id, 2);
1120                         assert_eq!(route.hops[0].fee_msat, 100);
1121                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1122
1123                         assert_eq!(route.hops[1].pubkey, node3);
1124                         assert_eq!(route.hops[1].short_channel_id, 4);
1125                         assert_eq!(route.hops[1].fee_msat, 0);
1126                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
1127
1128                         assert_eq!(route.hops[2].pubkey, node5);
1129                         assert_eq!(route.hops[2].short_channel_id, 6);
1130                         assert_eq!(route.hops[2].fee_msat, 0);
1131                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1132
1133                         assert_eq!(route.hops[3].pubkey, node4);
1134                         assert_eq!(route.hops[3].short_channel_id, 11);
1135                         assert_eq!(route.hops[3].fee_msat, 0);
1136                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1137
1138                         assert_eq!(route.hops[4].pubkey, node7);
1139                         assert_eq!(route.hops[4].short_channel_id, 8);
1140                         assert_eq!(route.hops[4].fee_msat, 100);
1141                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1142                 }
1143
1144                 { // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
1145                         let our_chans = vec![channelmanager::ChannelDetails {
1146                                 channel_id: [0; 32],
1147                                 short_channel_id: Some(42),
1148                                 remote_network_id: node4.clone(),
1149                                 channel_value_satoshis: 0,
1150                                 user_id: 0,
1151                         }];
1152                         let route = router.get_route(&node7, Some(&our_chans), &last_hops, 100, 42).unwrap();
1153                         assert_eq!(route.hops.len(), 2);
1154
1155                         assert_eq!(route.hops[0].pubkey, node4);
1156                         assert_eq!(route.hops[0].short_channel_id, 42);
1157                         assert_eq!(route.hops[0].fee_msat, 0);
1158                         assert_eq!(route.hops[0].cltv_expiry_delta, (8 << 8) | 1);
1159
1160                         assert_eq!(route.hops[1].pubkey, node7);
1161                         assert_eq!(route.hops[1].short_channel_id, 8);
1162                         assert_eq!(route.hops[1].fee_msat, 100);
1163                         assert_eq!(route.hops[1].cltv_expiry_delta, 42);
1164                 }
1165
1166                 last_hops[0].fee_base_msat = 1000;
1167
1168                 { // Revert to via 6 as the fee on 8 goes up
1169                         let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
1170                         assert_eq!(route.hops.len(), 4);
1171
1172                         assert_eq!(route.hops[0].pubkey, node2);
1173                         assert_eq!(route.hops[0].short_channel_id, 2);
1174                         assert_eq!(route.hops[0].fee_msat, 200); // fee increased as its % of value transferred across node
1175                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1176
1177                         assert_eq!(route.hops[1].pubkey, node3);
1178                         assert_eq!(route.hops[1].short_channel_id, 4);
1179                         assert_eq!(route.hops[1].fee_msat, 100);
1180                         assert_eq!(route.hops[1].cltv_expiry_delta, (7 << 8) | 1);
1181
1182                         assert_eq!(route.hops[2].pubkey, node6);
1183                         assert_eq!(route.hops[2].short_channel_id, 7);
1184                         assert_eq!(route.hops[2].fee_msat, 0);
1185                         assert_eq!(route.hops[2].cltv_expiry_delta, (10 << 8) | 1);
1186
1187                         assert_eq!(route.hops[3].pubkey, node7);
1188                         assert_eq!(route.hops[3].short_channel_id, 10);
1189                         assert_eq!(route.hops[3].fee_msat, 100);
1190                         assert_eq!(route.hops[3].cltv_expiry_delta, 42);
1191                 }
1192
1193                 { // ...but still use 8 for larger payments as 6 has a variable feerate
1194                         let route = router.get_route(&node7, None, &last_hops, 2000, 42).unwrap();
1195                         assert_eq!(route.hops.len(), 5);
1196
1197                         assert_eq!(route.hops[0].pubkey, node2);
1198                         assert_eq!(route.hops[0].short_channel_id, 2);
1199                         assert_eq!(route.hops[0].fee_msat, 3000);
1200                         assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
1201
1202                         assert_eq!(route.hops[1].pubkey, node3);
1203                         assert_eq!(route.hops[1].short_channel_id, 4);
1204                         assert_eq!(route.hops[1].fee_msat, 0);
1205                         assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
1206
1207                         assert_eq!(route.hops[2].pubkey, node5);
1208                         assert_eq!(route.hops[2].short_channel_id, 6);
1209                         assert_eq!(route.hops[2].fee_msat, 0);
1210                         assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
1211
1212                         assert_eq!(route.hops[3].pubkey, node4);
1213                         assert_eq!(route.hops[3].short_channel_id, 11);
1214                         assert_eq!(route.hops[3].fee_msat, 1000);
1215                         assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
1216
1217                         assert_eq!(route.hops[4].pubkey, node7);
1218                         assert_eq!(route.hops[4].short_channel_id, 8);
1219                         assert_eq!(route.hops[4].fee_msat, 2000);
1220                         assert_eq!(route.hops[4].cltv_expiry_delta, 42);
1221                 }
1222         }
1223 }