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