Merge pull request #379 from rrybarczyk/use-workspaces
[rust-lightning] / lightning / src / ln / router.rs
diff --git a/lightning/src/ln/router.rs b/lightning/src/ln/router.rs
new file mode 100644 (file)
index 0000000..5686e5a
--- /dev/null
@@ -0,0 +1,1633 @@
+//! The top-level routing/network map tracking logic lives here.
+//!
+//! You probably want to create a Router and use that as your RoutingMessageHandler and then
+//! interrogate it to get routes for your own payments.
+
+use secp256k1::key::PublicKey;
+use secp256k1::Secp256k1;
+use secp256k1;
+
+use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+use bitcoin_hashes::Hash;
+use bitcoin::blockdata::script::Builder;
+use bitcoin::blockdata::opcodes;
+
+use chain::chaininterface::{ChainError, ChainWatchInterface};
+use ln::channelmanager;
+use ln::msgs::{DecodeError,ErrorAction,LightningError,RoutingMessageHandler,NetAddress,GlobalFeatures};
+use ln::msgs;
+use util::ser::{Writeable, Readable, Writer, ReadableArgs};
+use util::logger::Logger;
+
+use std::cmp;
+use std::sync::{RwLock,Arc};
+use std::collections::{HashMap,BinaryHeap,BTreeMap};
+use std::collections::btree_map::Entry as BtreeEntry;
+use std;
+
+/// A hop in a route
+#[derive(Clone, PartialEq)]
+pub struct RouteHop {
+       /// The node_id of the node at this hop.
+       pub pubkey: PublicKey,
+       /// The channel that should be used from the previous hop to reach this node.
+       pub short_channel_id: u64,
+       /// The fee taken on this hop. For the last hop, this should be the full value of the payment.
+       pub fee_msat: u64,
+       /// The CLTV delta added for this hop. For the last hop, this should be the full CLTV value
+       /// expected at the destination, in excess of the current block height.
+       pub cltv_expiry_delta: u32,
+}
+
+/// A route from us through the network to a destination
+#[derive(Clone, PartialEq)]
+pub struct Route {
+       /// The list of hops, NOT INCLUDING our own, where the last hop is the destination. Thus, this
+       /// must always be at least length one. By protocol rules, this may not currently exceed 20 in
+       /// length.
+       pub hops: Vec<RouteHop>,
+}
+
+impl Writeable for Route {
+       fn write<W: ::util::ser::Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               (self.hops.len() as u8).write(writer)?;
+               for hop in self.hops.iter() {
+                       hop.pubkey.write(writer)?;
+                       hop.short_channel_id.write(writer)?;
+                       hop.fee_msat.write(writer)?;
+                       hop.cltv_expiry_delta.write(writer)?;
+               }
+               Ok(())
+       }
+}
+
+impl<R: ::std::io::Read> Readable<R> for Route {
+       fn read(reader: &mut R) -> Result<Route, DecodeError> {
+               let hops_count: u8 = Readable::read(reader)?;
+               let mut hops = Vec::with_capacity(hops_count as usize);
+               for _ in 0..hops_count {
+                       hops.push(RouteHop {
+                               pubkey: Readable::read(reader)?,
+                               short_channel_id: Readable::read(reader)?,
+                               fee_msat: Readable::read(reader)?,
+                               cltv_expiry_delta: Readable::read(reader)?,
+                       });
+               }
+               Ok(Route {
+                       hops
+               })
+       }
+}
+
+#[derive(PartialEq)]
+struct DirectionalChannelInfo {
+       src_node_id: PublicKey,
+       last_update: u32,
+       enabled: bool,
+       cltv_expiry_delta: u16,
+       htlc_minimum_msat: u64,
+       fee_base_msat: u32,
+       fee_proportional_millionths: u32,
+       last_update_message: Option<msgs::ChannelUpdate>,
+}
+
+impl std::fmt::Display for DirectionalChannelInfo {
+       fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+               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)?;
+               Ok(())
+       }
+}
+
+impl_writeable!(DirectionalChannelInfo, 0, {
+       src_node_id,
+       last_update,
+       enabled,
+       cltv_expiry_delta,
+       htlc_minimum_msat,
+       fee_base_msat,
+       fee_proportional_millionths,
+       last_update_message
+});
+
+#[derive(PartialEq)]
+struct ChannelInfo {
+       features: GlobalFeatures,
+       one_to_two: DirectionalChannelInfo,
+       two_to_one: DirectionalChannelInfo,
+       //this is cached here so we can send out it later if required by route_init_sync
+       //keep an eye on this to see if the extra memory is a problem
+       announcement_message: Option<msgs::ChannelAnnouncement>,
+}
+
+impl std::fmt::Display for ChannelInfo {
+       fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+               write!(f, "features: {}, one_to_two: {}, two_to_one: {}", log_bytes!(self.features.encode()), self.one_to_two, self.two_to_one)?;
+               Ok(())
+       }
+}
+
+impl_writeable!(ChannelInfo, 0, {
+       features,
+       one_to_two,
+       two_to_one,
+       announcement_message
+});
+
+#[derive(PartialEq)]
+struct NodeInfo {
+       #[cfg(feature = "non_bitcoin_chain_hash_routing")]
+       channels: Vec<(u64, Sha256dHash)>,
+       #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
+       channels: Vec<u64>,
+
+       lowest_inbound_channel_fee_base_msat: u32,
+       lowest_inbound_channel_fee_proportional_millionths: u32,
+
+       features: GlobalFeatures,
+       last_update: u32,
+       rgb: [u8; 3],
+       alias: [u8; 32],
+       addresses: Vec<NetAddress>,
+       //this is cached here so we can send out it later if required by route_init_sync
+       //keep an eye on this to see if the extra memory is a problem
+       announcement_message: Option<msgs::NodeAnnouncement>,
+}
+
+impl std::fmt::Display for NodeInfo {
+       fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+               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[..])?;
+               Ok(())
+       }
+}
+
+impl Writeable for NodeInfo {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               (self.channels.len() as u64).write(writer)?;
+               for ref chan in self.channels.iter() {
+                       chan.write(writer)?;
+               }
+               self.lowest_inbound_channel_fee_base_msat.write(writer)?;
+               self.lowest_inbound_channel_fee_proportional_millionths.write(writer)?;
+               self.features.write(writer)?;
+               self.last_update.write(writer)?;
+               self.rgb.write(writer)?;
+               self.alias.write(writer)?;
+               (self.addresses.len() as u64).write(writer)?;
+               for ref addr in &self.addresses {
+                       addr.write(writer)?;
+               }
+               self.announcement_message.write(writer)?;
+               Ok(())
+       }
+}
+
+const MAX_ALLOC_SIZE: u64 = 64*1024;
+
+impl<R: ::std::io::Read> Readable<R> for NodeInfo {
+       fn read(reader: &mut R) -> Result<NodeInfo, DecodeError> {
+               let channels_count: u64 = Readable::read(reader)?;
+               let mut channels = Vec::with_capacity(cmp::min(channels_count, MAX_ALLOC_SIZE / 8) as usize);
+               for _ in 0..channels_count {
+                       channels.push(Readable::read(reader)?);
+               }
+               let lowest_inbound_channel_fee_base_msat = Readable::read(reader)?;
+               let lowest_inbound_channel_fee_proportional_millionths = Readable::read(reader)?;
+               let features = Readable::read(reader)?;
+               let last_update = Readable::read(reader)?;
+               let rgb = Readable::read(reader)?;
+               let alias = Readable::read(reader)?;
+               let addresses_count: u64 = Readable::read(reader)?;
+               let mut addresses = Vec::with_capacity(cmp::min(addresses_count, MAX_ALLOC_SIZE / 40) as usize);
+               for _ in 0..addresses_count {
+                       match Readable::read(reader) {
+                               Ok(Ok(addr)) => { addresses.push(addr); },
+                               Ok(Err(_)) => return Err(DecodeError::InvalidValue),
+                               Err(DecodeError::ShortRead) => return Err(DecodeError::BadLengthDescriptor),
+                               _ => unreachable!(),
+                       }
+               }
+               let announcement_message = Readable::read(reader)?;
+               Ok(NodeInfo {
+                       channels,
+                       lowest_inbound_channel_fee_base_msat,
+                       lowest_inbound_channel_fee_proportional_millionths,
+                       features,
+                       last_update,
+                       rgb,
+                       alias,
+                       addresses,
+                       announcement_message
+               })
+       }
+}
+
+#[derive(PartialEq)]
+struct NetworkMap {
+       #[cfg(feature = "non_bitcoin_chain_hash_routing")]
+       channels: BTreeMap<(u64, Sha256dHash), ChannelInfo>,
+       #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
+       channels: BTreeMap<u64, ChannelInfo>,
+
+       our_node_id: PublicKey,
+       nodes: BTreeMap<PublicKey, NodeInfo>,
+}
+
+impl Writeable for NetworkMap {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               (self.channels.len() as u64).write(writer)?;
+               for (ref chan_id, ref chan_info) in self.channels.iter() {
+                       (*chan_id).write(writer)?;
+                       chan_info.write(writer)?;
+               }
+               self.our_node_id.write(writer)?;
+               (self.nodes.len() as u64).write(writer)?;
+               for (ref node_id, ref node_info) in self.nodes.iter() {
+                       node_id.write(writer)?;
+                       node_info.write(writer)?;
+               }
+               Ok(())
+       }
+}
+
+impl<R: ::std::io::Read> Readable<R> for NetworkMap {
+       fn read(reader: &mut R) -> Result<NetworkMap, DecodeError> {
+               let channels_count: u64 = Readable::read(reader)?;
+               let mut channels = BTreeMap::new();
+               for _ in 0..channels_count {
+                       let chan_id: u64 = Readable::read(reader)?;
+                       let chan_info = Readable::read(reader)?;
+                       channels.insert(chan_id, chan_info);
+               }
+               let our_node_id = Readable::read(reader)?;
+               let nodes_count: u64 = Readable::read(reader)?;
+               let mut nodes = BTreeMap::new();
+               for _ in 0..nodes_count {
+                       let node_id = Readable::read(reader)?;
+                       let node_info = Readable::read(reader)?;
+                       nodes.insert(node_id, node_info);
+               }
+               Ok(NetworkMap {
+                       channels,
+                       our_node_id,
+                       nodes,
+               })
+       }
+}
+
+struct MutNetworkMap<'a> {
+       #[cfg(feature = "non_bitcoin_chain_hash_routing")]
+       channels: &'a mut BTreeMap<(u64, Sha256dHash), ChannelInfo>,
+       #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
+       channels: &'a mut BTreeMap<u64, ChannelInfo>,
+       nodes: &'a mut BTreeMap<PublicKey, NodeInfo>,
+}
+impl NetworkMap {
+       fn borrow_parts(&mut self) -> MutNetworkMap {
+               MutNetworkMap {
+                       channels: &mut self.channels,
+                       nodes: &mut self.nodes,
+               }
+       }
+}
+impl std::fmt::Display for NetworkMap {
+       fn fmt(&self, f: &mut std::fmt::Formatter) -> Result<(), std::fmt::Error> {
+               write!(f, "Node id {} network map\n[Channels]\n", log_pubkey!(self.our_node_id))?;
+               for (key, val) in self.channels.iter() {
+                       write!(f, " {}: {}\n", key, val)?;
+               }
+               write!(f, "[Nodes]\n")?;
+               for (key, val) in self.nodes.iter() {
+                       write!(f, " {}: {}\n", log_pubkey!(key), val)?;
+               }
+               Ok(())
+       }
+}
+
+impl NetworkMap {
+       #[cfg(feature = "non_bitcoin_chain_hash_routing")]
+       #[inline]
+       fn get_key(short_channel_id: u64, chain_hash: Sha256dHash) -> (u64, Sha256dHash) {
+               (short_channel_id, chain_hash)
+       }
+
+       #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
+       #[inline]
+       fn get_key(short_channel_id: u64, _: Sha256dHash) -> u64 {
+               short_channel_id
+       }
+
+       #[cfg(feature = "non_bitcoin_chain_hash_routing")]
+       #[inline]
+       fn get_short_id(id: &(u64, Sha256dHash)) -> &u64 {
+               &id.0
+       }
+
+       #[cfg(not(feature = "non_bitcoin_chain_hash_routing"))]
+       #[inline]
+       fn get_short_id(id: &u64) -> &u64 {
+               id
+       }
+}
+
+/// A channel descriptor which provides a last-hop route to get_route
+pub struct RouteHint {
+       /// The node_id of the non-target end of the route
+       pub src_node_id: PublicKey,
+       /// The short_channel_id of this channel
+       pub short_channel_id: u64,
+       /// The static msat-denominated fee which must be paid to use this channel
+       pub fee_base_msat: u32,
+       /// The dynamic proportional fee which must be paid to use this channel, denominated in
+       /// millionths of the value being forwarded to the next hop.
+       pub fee_proportional_millionths: u32,
+       /// The difference in CLTV values between this node and the next node.
+       pub cltv_expiry_delta: u16,
+       /// The minimum value, in msat, which must be relayed to the next hop.
+       pub htlc_minimum_msat: u64,
+}
+
+/// Tracks a view of the network, receiving updates from peers and generating Routes to
+/// payment destinations.
+pub struct Router {
+       secp_ctx: Secp256k1<secp256k1::VerifyOnly>,
+       network_map: RwLock<NetworkMap>,
+       chain_monitor: Arc<ChainWatchInterface>,
+       logger: Arc<Logger>,
+}
+
+const SERIALIZATION_VERSION: u8 = 1;
+const MIN_SERIALIZATION_VERSION: u8 = 1;
+
+impl Writeable for Router {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               writer.write_all(&[SERIALIZATION_VERSION; 1])?;
+               writer.write_all(&[MIN_SERIALIZATION_VERSION; 1])?;
+
+               let network = self.network_map.read().unwrap();
+               network.write(writer)?;
+               Ok(())
+       }
+}
+
+/// Arguments for the creation of a Router that are not deserialized.
+/// At a high-level, the process for deserializing a Router and resuming normal operation is:
+/// 1) Deserialize the Router by filling in this struct and calling <Router>::read(reaser, args).
+/// 2) Register the new Router with your ChainWatchInterface
+pub struct RouterReadArgs {
+       /// The ChainWatchInterface for use in the Router in the future.
+       ///
+       /// No calls to the ChainWatchInterface will be made during deserialization.
+       pub chain_monitor: Arc<ChainWatchInterface>,
+       /// The Logger for use in the ChannelManager and which may be used to log information during
+       /// deserialization.
+       pub logger: Arc<Logger>,
+}
+
+impl<R: ::std::io::Read> ReadableArgs<R, RouterReadArgs> for Router {
+       fn read(reader: &mut R, args: RouterReadArgs) -> Result<Router, DecodeError> {
+               let _ver: u8 = Readable::read(reader)?;
+               let min_ver: u8 = Readable::read(reader)?;
+               if min_ver > SERIALIZATION_VERSION {
+                       return Err(DecodeError::UnknownVersion);
+               }
+               let network_map = Readable::read(reader)?;
+               Ok(Router {
+                       secp_ctx: Secp256k1::verification_only(),
+                       network_map: RwLock::new(network_map),
+                       chain_monitor: args.chain_monitor,
+                       logger: args.logger,
+               })
+       }
+}
+
+macro_rules! secp_verify_sig {
+       ( $secp_ctx: expr, $msg: expr, $sig: expr, $pubkey: expr ) => {
+               match $secp_ctx.verify($msg, $sig, $pubkey) {
+                       Ok(_) => {},
+                       Err(_) => return Err(LightningError{err: "Invalid signature from remote node", action: ErrorAction::IgnoreError}),
+               }
+       };
+}
+
+impl RoutingMessageHandler for Router {
+       fn handle_node_announcement(&self, msg: &msgs::NodeAnnouncement) -> Result<bool, LightningError> {
+               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
+               secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &msg.contents.node_id);
+
+               if msg.contents.features.requires_unknown_bits() {
+                       panic!("Unknown-required-features NodeAnnouncements should never deserialize!");
+               }
+
+               let mut network = self.network_map.write().unwrap();
+               match network.nodes.get_mut(&msg.contents.node_id) {
+                       None => Err(LightningError{err: "No existing channels for node_announcement", action: ErrorAction::IgnoreError}),
+                       Some(node) => {
+                               if node.last_update >= msg.contents.timestamp {
+                                       return Err(LightningError{err: "Update older than last processed update", action: ErrorAction::IgnoreError});
+                               }
+
+                               node.features = msg.contents.features.clone();
+                               node.last_update = msg.contents.timestamp;
+                               node.rgb = msg.contents.rgb;
+                               node.alias = msg.contents.alias;
+                               node.addresses = msg.contents.addresses.clone();
+
+                               let should_relay = msg.contents.excess_data.is_empty() && msg.contents.excess_address_data.is_empty() && !msg.contents.features.supports_unknown_bits();
+                               node.announcement_message = if should_relay { Some(msg.clone()) } else { None };
+                               Ok(should_relay)
+                       }
+               }
+       }
+
+       fn handle_channel_announcement(&self, msg: &msgs::ChannelAnnouncement) -> Result<bool, LightningError> {
+               if msg.contents.node_id_1 == msg.contents.node_id_2 || msg.contents.bitcoin_key_1 == msg.contents.bitcoin_key_2 {
+                       return Err(LightningError{err: "Channel announcement node had a channel with itself", action: ErrorAction::IgnoreError});
+               }
+
+               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
+               secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
+               secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
+               secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
+               secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
+
+               if msg.contents.features.requires_unknown_bits() {
+                       panic!("Unknown-required-features ChannelAnnouncements should never deserialize!");
+               }
+
+               let checked_utxo = match self.chain_monitor.get_chain_utxo(msg.contents.chain_hash, msg.contents.short_channel_id) {
+                       Ok((script_pubkey, _value)) => {
+                               let expected_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
+                                                                   .push_slice(&msg.contents.bitcoin_key_1.serialize())
+                                                                   .push_slice(&msg.contents.bitcoin_key_2.serialize())
+                                                                   .push_opcode(opcodes::all::OP_PUSHNUM_2)
+                                                                   .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
+                               if script_pubkey != expected_script {
+                                       return Err(LightningError{err: "Channel announcement keys didn't match on-chain script", action: ErrorAction::IgnoreError});
+                               }
+                               //TODO: Check if value is worth storing, use it to inform routing, and compare it
+                               //to the new HTLC max field in channel_update
+                               true
+                       },
+                       Err(ChainError::NotSupported) => {
+                               // Tentatively accept, potentially exposing us to DoS attacks
+                               false
+                       },
+                       Err(ChainError::NotWatched) => {
+                               return Err(LightningError{err: "Channel announced on an unknown chain", action: ErrorAction::IgnoreError});
+                       },
+                       Err(ChainError::UnknownTx) => {
+                               return Err(LightningError{err: "Channel announced without corresponding UTXO entry", action: ErrorAction::IgnoreError});
+                       },
+               };
+
+               let mut network_lock = self.network_map.write().unwrap();
+               let network = network_lock.borrow_parts();
+
+               let should_relay = msg.contents.excess_data.is_empty() && !msg.contents.features.supports_unknown_bits();
+
+               let chan_info = ChannelInfo {
+                               features: msg.contents.features.clone(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: msg.contents.node_id_1.clone(),
+                                       last_update: 0,
+                                       enabled: false,
+                                       cltv_expiry_delta: u16::max_value(),
+                                       htlc_minimum_msat: u64::max_value(),
+                                       fee_base_msat: u32::max_value(),
+                                       fee_proportional_millionths: u32::max_value(),
+                                       last_update_message: None,
+                               },
+                               two_to_one: DirectionalChannelInfo {
+                                       src_node_id: msg.contents.node_id_2.clone(),
+                                       last_update: 0,
+                                       enabled: false,
+                                       cltv_expiry_delta: u16::max_value(),
+                                       htlc_minimum_msat: u64::max_value(),
+                                       fee_base_msat: u32::max_value(),
+                                       fee_proportional_millionths: u32::max_value(),
+                                       last_update_message: None,
+                               },
+                               announcement_message: if should_relay { Some(msg.clone()) } else { None },
+                       };
+
+               match network.channels.entry(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
+                       BtreeEntry::Occupied(mut entry) => {
+                               //TODO: because asking the blockchain if short_channel_id is valid is only optional
+                               //in the blockchain API, we need to handle it smartly here, though it's unclear
+                               //exactly how...
+                               if checked_utxo {
+                                       // Either our UTXO provider is busted, there was a reorg, or the UTXO provider
+                                       // only sometimes returns results. In any case remove the previous entry. Note
+                                       // that the spec expects us to "blacklist" the node_ids involved, but we can't
+                                       // do that because
+                                       // a) we don't *require* a UTXO provider that always returns results.
+                                       // b) we don't track UTXOs of channels we know about and remove them if they
+                                       //    get reorg'd out.
+                                       // c) it's unclear how to do so without exposing ourselves to massive DoS risk.
+                                       Self::remove_channel_in_nodes(network.nodes, &entry.get(), msg.contents.short_channel_id);
+                                       *entry.get_mut() = chan_info;
+                               } else {
+                                       return Err(LightningError{err: "Already have knowledge of channel", action: ErrorAction::IgnoreError})
+                               }
+                       },
+                       BtreeEntry::Vacant(entry) => {
+                               entry.insert(chan_info);
+                       }
+               };
+
+               macro_rules! add_channel_to_node {
+                       ( $node_id: expr ) => {
+                               match network.nodes.entry($node_id) {
+                                       BtreeEntry::Occupied(node_entry) => {
+                                               node_entry.into_mut().channels.push(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash));
+                                       },
+                                       BtreeEntry::Vacant(node_entry) => {
+                                               node_entry.insert(NodeInfo {
+                                                       channels: vec!(NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)),
+                                                       lowest_inbound_channel_fee_base_msat: u32::max_value(),
+                                                       lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
+                                                       features: GlobalFeatures::new(),
+                                                       last_update: 0,
+                                                       rgb: [0; 3],
+                                                       alias: [0; 32],
+                                                       addresses: Vec::new(),
+                                                       announcement_message: None,
+                                               });
+                                       }
+                               }
+                       };
+               }
+
+               add_channel_to_node!(msg.contents.node_id_1);
+               add_channel_to_node!(msg.contents.node_id_2);
+
+               Ok(should_relay)
+       }
+
+       fn handle_htlc_fail_channel_update(&self, update: &msgs::HTLCFailChannelUpdate) {
+               match update {
+                       &msgs::HTLCFailChannelUpdate::ChannelUpdateMessage { ref msg } => {
+                               let _ = self.handle_channel_update(msg);
+                       },
+                       &msgs::HTLCFailChannelUpdate::ChannelClosed { ref short_channel_id, ref is_permanent } => {
+                               let mut network = self.network_map.write().unwrap();
+                               if *is_permanent {
+                                       if let Some(chan) = network.channels.remove(short_channel_id) {
+                                               Self::remove_channel_in_nodes(&mut network.nodes, &chan, *short_channel_id);
+                                       }
+                               } else {
+                                       if let Some(chan) = network.channels.get_mut(short_channel_id) {
+                                               chan.one_to_two.enabled = false;
+                                               chan.two_to_one.enabled = false;
+                                       }
+                               }
+                       },
+                       &msgs::HTLCFailChannelUpdate::NodeFailure { ref node_id, ref is_permanent } => {
+                               if *is_permanent {
+                                       //TODO: Wholly remove the node
+                               } else {
+                                       self.mark_node_bad(node_id, false);
+                               }
+                       },
+               }
+       }
+
+       fn handle_channel_update(&self, msg: &msgs::ChannelUpdate) -> Result<bool, LightningError> {
+               let mut network = self.network_map.write().unwrap();
+               let dest_node_id;
+               let chan_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
+               let chan_was_enabled;
+
+               match network.channels.get_mut(&NetworkMap::get_key(msg.contents.short_channel_id, msg.contents.chain_hash)) {
+                       None => return Err(LightningError{err: "Couldn't find channel for update", action: ErrorAction::IgnoreError}),
+                       Some(channel) => {
+                               macro_rules! maybe_update_channel_info {
+                                       ( $target: expr) => {
+                                               if $target.last_update >= msg.contents.timestamp {
+                                                       return Err(LightningError{err: "Update older than last processed update", action: ErrorAction::IgnoreError});
+                                               }
+                                               chan_was_enabled = $target.enabled;
+                                               $target.last_update = msg.contents.timestamp;
+                                               $target.enabled = chan_enabled;
+                                               $target.cltv_expiry_delta = msg.contents.cltv_expiry_delta;
+                                               $target.htlc_minimum_msat = msg.contents.htlc_minimum_msat;
+                                               $target.fee_base_msat = msg.contents.fee_base_msat;
+                                               $target.fee_proportional_millionths = msg.contents.fee_proportional_millionths;
+                                               $target.last_update_message = if msg.contents.excess_data.is_empty() {
+                                                       Some(msg.clone())
+                                               } else {
+                                                       None
+                                               };
+                                       }
+                               }
+                               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
+                               if msg.contents.flags & 1 == 1 {
+                                       dest_node_id = channel.one_to_two.src_node_id.clone();
+                                       secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.two_to_one.src_node_id);
+                                       maybe_update_channel_info!(channel.two_to_one);
+                               } else {
+                                       dest_node_id = channel.two_to_one.src_node_id.clone();
+                                       secp_verify_sig!(self.secp_ctx, &msg_hash, &msg.signature, &channel.one_to_two.src_node_id);
+                                       maybe_update_channel_info!(channel.one_to_two);
+                               }
+                       }
+               }
+
+               if chan_enabled {
+                       let node = network.nodes.get_mut(&dest_node_id).unwrap();
+                       node.lowest_inbound_channel_fee_base_msat = cmp::min(node.lowest_inbound_channel_fee_base_msat, msg.contents.fee_base_msat);
+                       node.lowest_inbound_channel_fee_proportional_millionths = cmp::min(node.lowest_inbound_channel_fee_proportional_millionths, msg.contents.fee_proportional_millionths);
+               } else if chan_was_enabled {
+                       let mut lowest_inbound_channel_fee_base_msat = u32::max_value();
+                       let mut lowest_inbound_channel_fee_proportional_millionths = u32::max_value();
+
+                       {
+                               let node = network.nodes.get(&dest_node_id).unwrap();
+
+                               for chan_id in node.channels.iter() {
+                                       let chan = network.channels.get(chan_id).unwrap();
+                                       if chan.one_to_two.src_node_id == dest_node_id {
+                                               lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.two_to_one.fee_base_msat);
+                                               lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.two_to_one.fee_proportional_millionths);
+                                       } else {
+                                               lowest_inbound_channel_fee_base_msat = cmp::min(lowest_inbound_channel_fee_base_msat, chan.one_to_two.fee_base_msat);
+                                               lowest_inbound_channel_fee_proportional_millionths = cmp::min(lowest_inbound_channel_fee_proportional_millionths, chan.one_to_two.fee_proportional_millionths);
+                                       }
+                               }
+                       }
+
+                       //TODO: satisfy the borrow-checker without a double-map-lookup :(
+                       let mut_node = network.nodes.get_mut(&dest_node_id).unwrap();
+                       mut_node.lowest_inbound_channel_fee_base_msat = lowest_inbound_channel_fee_base_msat;
+                       mut_node.lowest_inbound_channel_fee_proportional_millionths = lowest_inbound_channel_fee_proportional_millionths;
+               }
+
+               Ok(msg.contents.excess_data.is_empty())
+       }
+
+
+       fn get_next_channel_announcements(&self, starting_point: u64, batch_amount: u8) -> Vec<(msgs::ChannelAnnouncement, msgs::ChannelUpdate,msgs::ChannelUpdate)> {
+               let mut result = Vec::with_capacity(batch_amount as usize);
+               let network = self.network_map.read().unwrap();
+               let mut iter = network.channels.range(starting_point..);
+               while result.len() < batch_amount as usize {
+                       if let Some((_, ref chan)) = iter.next() {
+                               if chan.announcement_message.is_some() &&
+                                               chan.one_to_two.last_update_message.is_some() &&
+                                               chan.two_to_one.last_update_message.is_some() {
+                                       result.push((chan.announcement_message.clone().unwrap(),
+                                               chan.one_to_two.last_update_message.clone().unwrap(),
+                                               chan.two_to_one.last_update_message.clone().unwrap()));
+                               } else {
+                                       // TODO: We may end up sending un-announced channel_updates if we are sending
+                                       // initial sync data while receiving announce/updates for this channel.
+                               }
+                       } else {
+                               return result;
+                       }
+               }
+               result
+       }
+
+       fn get_next_node_announcements(&self, starting_point: Option<&PublicKey>, batch_amount: u8) -> Vec<msgs::NodeAnnouncement> {
+               let mut result = Vec::with_capacity(batch_amount as usize);
+               let network = self.network_map.read().unwrap();
+               let mut iter = if let Some(pubkey) = starting_point {
+                               let mut iter = network.nodes.range((*pubkey)..);
+                               iter.next();
+                               iter
+                       } else {
+                               network.nodes.range(..)
+                       };
+               while result.len() < batch_amount as usize {
+                       if let Some((_, ref node)) = iter.next() {
+                               if node.announcement_message.is_some() {
+                                       result.push(node.announcement_message.clone().unwrap());
+                               }
+                       } else {
+                               return result;
+                       }
+               }
+               result
+       }
+}
+
+#[derive(Eq, PartialEq)]
+struct RouteGraphNode {
+       pubkey: PublicKey,
+       lowest_fee_to_peer_through_node: u64,
+       lowest_fee_to_node: u64,
+}
+
+impl cmp::Ord for RouteGraphNode {
+       fn cmp(&self, other: &RouteGraphNode) -> cmp::Ordering {
+               other.lowest_fee_to_peer_through_node.cmp(&self.lowest_fee_to_peer_through_node)
+                       .then_with(|| other.pubkey.serialize().cmp(&self.pubkey.serialize()))
+       }
+}
+
+impl cmp::PartialOrd for RouteGraphNode {
+       fn partial_cmp(&self, other: &RouteGraphNode) -> Option<cmp::Ordering> {
+               Some(self.cmp(other))
+       }
+}
+
+struct DummyDirectionalChannelInfo {
+       src_node_id: PublicKey,
+       cltv_expiry_delta: u32,
+       htlc_minimum_msat: u64,
+       fee_base_msat: u32,
+       fee_proportional_millionths: u32,
+}
+
+impl Router {
+       /// Creates a new router with the given node_id to be used as the source for get_route()
+       pub fn new(our_pubkey: PublicKey, chain_monitor: Arc<ChainWatchInterface>, logger: Arc<Logger>) -> Router {
+               let mut nodes = BTreeMap::new();
+               nodes.insert(our_pubkey.clone(), NodeInfo {
+                       channels: Vec::new(),
+                       lowest_inbound_channel_fee_base_msat: u32::max_value(),
+                       lowest_inbound_channel_fee_proportional_millionths: u32::max_value(),
+                       features: GlobalFeatures::new(),
+                       last_update: 0,
+                       rgb: [0; 3],
+                       alias: [0; 32],
+                       addresses: Vec::new(),
+                       announcement_message: None,
+               });
+               Router {
+                       secp_ctx: Secp256k1::verification_only(),
+                       network_map: RwLock::new(NetworkMap {
+                               channels: BTreeMap::new(),
+                               our_node_id: our_pubkey,
+                               nodes: nodes,
+                       }),
+                       chain_monitor,
+                       logger,
+               }
+       }
+
+       /// Dumps the entire network view of this Router to the logger provided in the constructor at
+       /// level Trace
+       pub fn trace_state(&self) {
+               log_trace!(self, "{}", self.network_map.read().unwrap());
+       }
+
+       /// Get network addresses by node id
+       pub fn get_addresses(&self, pubkey: &PublicKey) -> Option<Vec<NetAddress>> {
+               let network = self.network_map.read().unwrap();
+               network.nodes.get(pubkey).map(|n| n.addresses.clone())
+       }
+
+       /// Marks a node as having failed a route. This will avoid re-using the node in routes for now,
+       /// with an exponential decay in node "badness". Note that there is deliberately no
+       /// mark_channel_bad as a node may simply lie and suggest that an upstream channel from it is
+       /// what failed the route and not the node itself. Instead, setting the blamed_upstream_node
+       /// boolean will reduce the penalty, returning the node to usability faster. If the node is
+       /// behaving correctly, it will disable the failing channel and we will use it again next time.
+       pub fn mark_node_bad(&self, _node_id: &PublicKey, _blamed_upstream_node: bool) {
+               unimplemented!();
+       }
+
+       fn remove_channel_in_nodes(nodes: &mut BTreeMap<PublicKey, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
+               macro_rules! remove_from_node {
+                       ($node_id: expr) => {
+                               if let BtreeEntry::Occupied(mut entry) = nodes.entry($node_id) {
+                                       entry.get_mut().channels.retain(|chan_id| {
+                                               short_channel_id != *NetworkMap::get_short_id(chan_id)
+                                       });
+                                       if entry.get().channels.is_empty() {
+                                               entry.remove_entry();
+                                       }
+                               } else {
+                                       panic!("Had channel that pointed to unknown node (ie inconsistent network map)!");
+                               }
+                       }
+               }
+               remove_from_node!(chan.one_to_two.src_node_id);
+               remove_from_node!(chan.two_to_one.src_node_id);
+       }
+
+       /// Gets a route from us to the given target node.
+       ///
+       /// Extra routing hops between known nodes and the target will be used if they are included in
+       /// last_hops.
+       ///
+       /// If some channels aren't announced, it may be useful to fill in a first_hops with the
+       /// results from a local ChannelManager::list_usable_channels() call. If it is filled in, our
+       /// (this Router's) view of our local channels will be ignored, and only those in first_hops
+       /// will be used.
+       ///
+       /// Panics if first_hops contains channels without short_channel_ids
+       /// (ChannelManager::list_usable_channels will never include such channels).
+       ///
+       /// The fees on channels from us to next-hops are ignored (as they are assumed to all be
+       /// equal), however the enabled/disabled bit on such channels as well as the htlc_minimum_msat
+       /// *is* checked as they may change based on the receiving node.
+       pub fn get_route(&self, target: &PublicKey, first_hops: Option<&[channelmanager::ChannelDetails]>, last_hops: &[RouteHint], final_value_msat: u64, final_cltv: u32) -> Result<Route, LightningError> {
+               // TODO: Obviously *only* using total fee cost sucks. We should consider weighting by
+               // uptime/success in using a node in the past.
+               let network = self.network_map.read().unwrap();
+
+               if *target == network.our_node_id {
+                       return Err(LightningError{err: "Cannot generate a route to ourselves", action: ErrorAction::IgnoreError});
+               }
+
+               if final_value_msat > 21_000_000 * 1_0000_0000 * 1000 {
+                       return Err(LightningError{err: "Cannot generate a route of more value than all existing satoshis", action: ErrorAction::IgnoreError});
+               }
+
+               // We do a dest-to-source Dijkstra's sorting by each node's distance from the destination
+               // plus the minimum per-HTLC fee to get from it to another node (aka "shitty A*").
+               // TODO: There are a few tweaks we could do, including possibly pre-calculating more stuff
+               // to use as the A* heuristic beyond just the cost to get one node further than the current
+               // one.
+
+               let dummy_directional_info = DummyDirectionalChannelInfo { // used for first_hops routes
+                       src_node_id: network.our_node_id.clone(),
+                       cltv_expiry_delta: 0,
+                       htlc_minimum_msat: 0,
+                       fee_base_msat: 0,
+                       fee_proportional_millionths: 0,
+               };
+
+               let mut targets = BinaryHeap::new(); //TODO: Do we care about switching to eg Fibbonaci heap?
+               let mut dist = HashMap::with_capacity(network.nodes.len());
+
+               let mut first_hop_targets = HashMap::with_capacity(if first_hops.is_some() { first_hops.as_ref().unwrap().len() } else { 0 });
+               if let Some(hops) = first_hops {
+                       for chan in hops {
+                               let short_channel_id = chan.short_channel_id.expect("first_hops should be filled in with usable channels, not pending ones");
+                               if chan.remote_network_id == *target {
+                                       return Ok(Route {
+                                               hops: vec![RouteHop {
+                                                       pubkey: chan.remote_network_id,
+                                                       short_channel_id,
+                                                       fee_msat: final_value_msat,
+                                                       cltv_expiry_delta: final_cltv,
+                                               }],
+                                       });
+                               }
+                               first_hop_targets.insert(chan.remote_network_id, short_channel_id);
+                       }
+                       if first_hop_targets.is_empty() {
+                               return Err(LightningError{err: "Cannot route when there are no outbound routes away from us", action: ErrorAction::IgnoreError});
+                       }
+               }
+
+               macro_rules! add_entry {
+                       // Adds entry which goes from the node pointed to by $directional_info to
+                       // $dest_node_id over the channel with id $chan_id with fees described in
+                       // $directional_info.
+                       ( $chan_id: expr, $dest_node_id: expr, $directional_info: expr, $starting_fee_msat: expr ) => {
+                               //TODO: Explore simply adding fee to hit htlc_minimum_msat
+                               if $starting_fee_msat as u64 + final_value_msat >= $directional_info.htlc_minimum_msat {
+                                       let proportional_fee_millions = ($starting_fee_msat + final_value_msat).checked_mul($directional_info.fee_proportional_millionths as u64);
+                                       if let Some(new_fee) = proportional_fee_millions.and_then(|part| {
+                                                       ($directional_info.fee_base_msat as u64).checked_add(part / 1000000) })
+                                       {
+                                               let mut total_fee = $starting_fee_msat as u64;
+                                               let hm_entry = dist.entry(&$directional_info.src_node_id);
+                                               let old_entry = hm_entry.or_insert_with(|| {
+                                                       let node = network.nodes.get(&$directional_info.src_node_id).unwrap();
+                                                       (u64::max_value(),
+                                                               node.lowest_inbound_channel_fee_base_msat,
+                                                               node.lowest_inbound_channel_fee_proportional_millionths,
+                                                               RouteHop {
+                                                                       pubkey: $dest_node_id.clone(),
+                                                                       short_channel_id: 0,
+                                                                       fee_msat: 0,
+                                                                       cltv_expiry_delta: 0,
+                                                       })
+                                               });
+                                               if $directional_info.src_node_id != network.our_node_id {
+                                                       // Ignore new_fee for channel-from-us as we assume all channels-from-us
+                                                       // will have the same effective-fee
+                                                       total_fee += new_fee;
+                                                       if let Some(fee_inc) = final_value_msat.checked_add(total_fee).and_then(|inc| { (old_entry.2 as u64).checked_mul(inc) }) {
+                                                               total_fee += fee_inc / 1000000 + (old_entry.1 as u64);
+                                                       } else {
+                                                               // max_value means we'll always fail the old_entry.0 > total_fee check
+                                                               total_fee = u64::max_value();
+                                                       }
+                                               }
+                                               let new_graph_node = RouteGraphNode {
+                                                       pubkey: $directional_info.src_node_id,
+                                                       lowest_fee_to_peer_through_node: total_fee,
+                                                       lowest_fee_to_node: $starting_fee_msat as u64 + new_fee,
+                                               };
+                                               if old_entry.0 > total_fee {
+                                                       targets.push(new_graph_node);
+                                                       old_entry.0 = total_fee;
+                                                       old_entry.3 = RouteHop {
+                                                               pubkey: $dest_node_id.clone(),
+                                                               short_channel_id: $chan_id.clone(),
+                                                               fee_msat: new_fee, // This field is ignored on the last-hop anyway
+                                                               cltv_expiry_delta: $directional_info.cltv_expiry_delta as u32,
+                                                       }
+                                               }
+                                       }
+                               }
+                       };
+               }
+
+               macro_rules! add_entries_to_cheapest_to_target_node {
+                       ( $node: expr, $node_id: expr, $fee_to_target_msat: expr ) => {
+                               if first_hops.is_some() {
+                                       if let Some(first_hop) = first_hop_targets.get(&$node_id) {
+                                               add_entry!(first_hop, $node_id, dummy_directional_info, $fee_to_target_msat);
+                                       }
+                               }
+
+                               for chan_id in $node.channels.iter() {
+                                       let chan = network.channels.get(chan_id).unwrap();
+                                       if chan.one_to_two.src_node_id == *$node_id {
+                                               // ie $node is one, ie next hop in A* is two, via the two_to_one channel
+                                               if first_hops.is_none() || chan.two_to_one.src_node_id != network.our_node_id {
+                                                       if chan.two_to_one.enabled {
+                                                               add_entry!(chan_id, chan.one_to_two.src_node_id, chan.two_to_one, $fee_to_target_msat);
+                                                       }
+                                               }
+                                       } else {
+                                               if first_hops.is_none() || chan.one_to_two.src_node_id != network.our_node_id {
+                                                       if chan.one_to_two.enabled {
+                                                               add_entry!(chan_id, chan.two_to_one.src_node_id, chan.one_to_two, $fee_to_target_msat);
+                                                       }
+                                               }
+                                       }
+                               }
+                       };
+               }
+
+               match network.nodes.get(target) {
+                       None => {},
+                       Some(node) => {
+                               add_entries_to_cheapest_to_target_node!(node, target, 0);
+                       },
+               }
+
+               for hop in last_hops.iter() {
+                       if first_hops.is_none() || hop.src_node_id != network.our_node_id { // first_hop overrules last_hops
+                               if network.nodes.get(&hop.src_node_id).is_some() {
+                                       if first_hops.is_some() {
+                                               if let Some(first_hop) = first_hop_targets.get(&hop.src_node_id) {
+                                                       add_entry!(first_hop, hop.src_node_id, dummy_directional_info, 0);
+                                               }
+                                       }
+                                       add_entry!(hop.short_channel_id, target, hop, 0);
+                               }
+                       }
+               }
+
+               while let Some(RouteGraphNode { pubkey, lowest_fee_to_node, .. }) = targets.pop() {
+                       if pubkey == network.our_node_id {
+                               let mut res = vec!(dist.remove(&network.our_node_id).unwrap().3);
+                               while res.last().unwrap().pubkey != *target {
+                                       let new_entry = match dist.remove(&res.last().unwrap().pubkey) {
+                                               Some(hop) => hop.3,
+                                               None => return Err(LightningError{err: "Failed to find a non-fee-overflowing path to the given destination", action: ErrorAction::IgnoreError}),
+                                       };
+                                       res.last_mut().unwrap().fee_msat = new_entry.fee_msat;
+                                       res.last_mut().unwrap().cltv_expiry_delta = new_entry.cltv_expiry_delta;
+                                       res.push(new_entry);
+                               }
+                               res.last_mut().unwrap().fee_msat = final_value_msat;
+                               res.last_mut().unwrap().cltv_expiry_delta = final_cltv;
+                               let route = Route { hops: res };
+                               log_trace!(self, "Got route: {}", log_route!(route));
+                               return Ok(route);
+                       }
+
+                       match network.nodes.get(&pubkey) {
+                               None => {},
+                               Some(node) => {
+                                       add_entries_to_cheapest_to_target_node!(node, &pubkey, lowest_fee_to_node);
+                               },
+                       }
+               }
+
+               Err(LightningError{err: "Failed to find a path to the given destination", action: ErrorAction::IgnoreError})
+       }
+}
+
+#[cfg(test)]
+mod tests {
+       use chain::chaininterface;
+       use ln::channelmanager;
+       use ln::router::{Router,NodeInfo,NetworkMap,ChannelInfo,DirectionalChannelInfo,RouteHint};
+       use ln::msgs::GlobalFeatures;
+       use util::test_utils;
+       use util::test_utils::TestVecWriter;
+       use util::logger::Logger;
+       use util::ser::{Writeable, Readable};
+
+       use bitcoin_hashes::sha256d::Hash as Sha256dHash;
+       use bitcoin_hashes::Hash;
+       use bitcoin::network::constants::Network;
+
+       use hex;
+
+       use secp256k1::key::{PublicKey,SecretKey};
+       use secp256k1::Secp256k1;
+
+       use std::sync::Arc;
+
+       #[test]
+       fn route_test() {
+               let secp_ctx = Secp256k1::new();
+               let our_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0101010101010101010101010101010101010101010101010101010101010101").unwrap()[..]).unwrap());
+               let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());
+               let chain_monitor = Arc::new(chaininterface::ChainWatchInterfaceUtil::new(Network::Testnet, Arc::clone(&logger)));
+               let router = Router::new(our_id, chain_monitor, Arc::clone(&logger));
+
+               // Build network from our_id to node8:
+               //
+               //        -1(1)2-  node1  -1(3)2-
+               //       /                       \
+               // our_id -1(12)2- node8 -1(13)2--- node3
+               //       \                       /
+               //        -1(2)2-  node2  -1(4)2-
+               //
+               //
+               // chan1  1-to-2: disabled
+               // chan1  2-to-1: enabled, 0 fee
+               //
+               // chan2  1-to-2: enabled, ignored fee
+               // chan2  2-to-1: enabled, 0 fee
+               //
+               // chan3  1-to-2: enabled, 0 fee
+               // chan3  2-to-1: enabled, 100 msat fee
+               //
+               // chan4  1-to-2: enabled, 100% fee
+               // chan4  2-to-1: enabled, 0 fee
+               //
+               // chan12 1-to-2: enabled, ignored fee
+               // chan12 2-to-1: enabled, 0 fee
+               //
+               // chan13 1-to-2: enabled, 200% fee
+               // chan13 2-to-1: enabled, 0 fee
+               //
+               //
+               //       -1(5)2- node4 -1(8)2--
+               //       |         2          |
+               //       |       (11)         |
+               //      /          1           \
+               // node3--1(6)2- node5 -1(9)2--- node7 (not in global route map)
+               //      \                      /
+               //       -1(7)2- node6 -1(10)2-
+               //
+               // chan5  1-to-2: enabled, 100 msat fee
+               // chan5  2-to-1: enabled, 0 fee
+               //
+               // chan6  1-to-2: enabled, 0 fee
+               // chan6  2-to-1: enabled, 0 fee
+               //
+               // chan7  1-to-2: enabled, 100% fee
+               // chan7  2-to-1: enabled, 0 fee
+               //
+               // chan8  1-to-2: enabled, variable fee (0 then 1000 msat)
+               // chan8  2-to-1: enabled, 0 fee
+               //
+               // chan9  1-to-2: enabled, 1001 msat fee
+               // chan9  2-to-1: enabled, 0 fee
+               //
+               // chan10 1-to-2: enabled, 0 fee
+               // chan10 2-to-1: enabled, 0 fee
+               //
+               // chan11 1-to-2: enabled, 0 fee
+               // chan11 2-to-1: enabled, 0 fee
+
+               let node1 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap());
+               let node2 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0303030303030303030303030303030303030303030303030303030303030303").unwrap()[..]).unwrap());
+               let node3 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0404040404040404040404040404040404040404040404040404040404040404").unwrap()[..]).unwrap());
+               let node4 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0505050505050505050505050505050505050505050505050505050505050505").unwrap()[..]).unwrap());
+               let node5 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0606060606060606060606060606060606060606060606060606060606060606").unwrap()[..]).unwrap());
+               let node6 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0707070707070707070707070707070707070707070707070707070707070707").unwrap()[..]).unwrap());
+               let node7 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0808080808080808080808080808080808080808080808080808080808080808").unwrap()[..]).unwrap());
+               let node8 = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0909090909090909090909090909090909090909090909090909090909090909").unwrap()[..]).unwrap());
+
+               let zero_hash = Sha256dHash::hash(&[0; 32]);
+
+               {
+                       let mut network = router.network_map.write().unwrap();
+
+                       network.nodes.insert(node1.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(1, zero_hash.clone()), NetworkMap::get_key(3, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 100,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(1, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: our_id.clone(),
+                                       last_update: 0,
+                                       enabled: false,
+                                       cltv_expiry_delta: u16::max_value(), // This value should be ignored
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: u32::max_value(), // This value should be ignored
+                                       fee_proportional_millionths: u32::max_value(), // This value should be ignored
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node1.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: 0,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node2.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(2, zero_hash.clone()), NetworkMap::get_key(4, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(2, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: our_id.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: u16::max_value(), // This value should be ignored
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: u32::max_value(), // This value should be ignored
+                                       fee_proportional_millionths: u32::max_value(), // This value should be ignored
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node2.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: 0,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node8.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(12, zero_hash.clone()), NetworkMap::get_key(13, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(12, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: our_id.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: u16::max_value(), // This value should be ignored
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: u32::max_value(), // This value should be ignored
+                                       fee_proportional_millionths: u32::max_value(), // This value should be ignored
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node8.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: 0,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node3.clone(), NodeInfo {
+                               channels: vec!(
+                                       NetworkMap::get_key(3, zero_hash.clone()),
+                                       NetworkMap::get_key(4, zero_hash.clone()),
+                                       NetworkMap::get_key(13, zero_hash.clone()),
+                                       NetworkMap::get_key(5, zero_hash.clone()),
+                                       NetworkMap::get_key(6, zero_hash.clone()),
+                                       NetworkMap::get_key(7, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(3, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node1.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (3 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (3 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 100,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(4, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node2.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (4 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 1000000,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (4 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(13, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node8.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (13 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 2000000,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (13 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node4.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(5, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(5, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (5 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 100,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node4.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (5 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node5.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(6, zero_hash.clone()), NetworkMap::get_key(11, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(6, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (6 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node5.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (6 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(11, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node5.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (11 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node4.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (11 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+                       network.nodes.insert(node6.clone(), NodeInfo {
+                               channels: vec!(NetworkMap::get_key(7, zero_hash.clone())),
+                               lowest_inbound_channel_fee_base_msat: 0,
+                               lowest_inbound_channel_fee_proportional_millionths: 0,
+                               features: GlobalFeatures::new(),
+                               last_update: 1,
+                               rgb: [0; 3],
+                               alias: [0; 32],
+                               addresses: Vec::new(),
+                               announcement_message: None,
+                       });
+                       network.channels.insert(NetworkMap::get_key(7, zero_hash.clone()), ChannelInfo {
+                               features: GlobalFeatures::new(),
+                               one_to_two: DirectionalChannelInfo {
+                                       src_node_id: node3.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (7 << 8) | 1,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 1000000,
+                                       last_update_message: None,
+                               }, two_to_one: DirectionalChannelInfo {
+                                       src_node_id: node6.clone(),
+                                       last_update: 0,
+                                       enabled: true,
+                                       cltv_expiry_delta: (7 << 8) | 2,
+                                       htlc_minimum_msat: 0,
+                                       fee_base_msat: 0,
+                                       fee_proportional_millionths: 0,
+                                       last_update_message: None,
+                               },
+                               announcement_message: None,
+                       });
+               }
+
+               { // Simple route to 3 via 2
+                       let route = router.get_route(&node3, None, &Vec::new(), 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 2);
+
+                       assert_eq!(route.hops[0].pubkey, node2);
+                       assert_eq!(route.hops[0].short_channel_id, 2);
+                       assert_eq!(route.hops[0].fee_msat, 100);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 4);
+                       assert_eq!(route.hops[1].fee_msat, 100);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, 42);
+               }
+
+               { // Route to 1 via 2 and 3 because our channel to 1 is disabled
+                       let route = router.get_route(&node1, None, &Vec::new(), 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 3);
+
+                       assert_eq!(route.hops[0].pubkey, node2);
+                       assert_eq!(route.hops[0].short_channel_id, 2);
+                       assert_eq!(route.hops[0].fee_msat, 200);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 4);
+                       assert_eq!(route.hops[1].fee_msat, 100);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, (3 << 8) | 2);
+
+                       assert_eq!(route.hops[2].pubkey, node1);
+                       assert_eq!(route.hops[2].short_channel_id, 3);
+                       assert_eq!(route.hops[2].fee_msat, 100);
+                       assert_eq!(route.hops[2].cltv_expiry_delta, 42);
+               }
+
+               { // If we specify a channel to node8, that overrides our local channel view and that gets used
+                       let our_chans = vec![channelmanager::ChannelDetails {
+                               channel_id: [0; 32],
+                               short_channel_id: Some(42),
+                               remote_network_id: node8.clone(),
+                               channel_value_satoshis: 0,
+                               user_id: 0,
+                               outbound_capacity_msat: 0,
+                               inbound_capacity_msat: 0,
+                               is_live: true,
+                       }];
+                       let route = router.get_route(&node3, Some(&our_chans), &Vec::new(), 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 2);
+
+                       assert_eq!(route.hops[0].pubkey, node8);
+                       assert_eq!(route.hops[0].short_channel_id, 42);
+                       assert_eq!(route.hops[0].fee_msat, 200);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (13 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 13);
+                       assert_eq!(route.hops[1].fee_msat, 100);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, 42);
+               }
+
+               let mut last_hops = vec!(RouteHint {
+                               src_node_id: node4.clone(),
+                               short_channel_id: 8,
+                               fee_base_msat: 0,
+                               fee_proportional_millionths: 0,
+                               cltv_expiry_delta: (8 << 8) | 1,
+                               htlc_minimum_msat: 0,
+                       }, RouteHint {
+                               src_node_id: node5.clone(),
+                               short_channel_id: 9,
+                               fee_base_msat: 1001,
+                               fee_proportional_millionths: 0,
+                               cltv_expiry_delta: (9 << 8) | 1,
+                               htlc_minimum_msat: 0,
+                       }, RouteHint {
+                               src_node_id: node6.clone(),
+                               short_channel_id: 10,
+                               fee_base_msat: 0,
+                               fee_proportional_millionths: 0,
+                               cltv_expiry_delta: (10 << 8) | 1,
+                               htlc_minimum_msat: 0,
+                       });
+
+               { // Simple test across 2, 3, 5, and 4 via a last_hop channel
+                       let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 5);
+
+                       assert_eq!(route.hops[0].pubkey, node2);
+                       assert_eq!(route.hops[0].short_channel_id, 2);
+                       assert_eq!(route.hops[0].fee_msat, 100);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 4);
+                       assert_eq!(route.hops[1].fee_msat, 0);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
+
+                       assert_eq!(route.hops[2].pubkey, node5);
+                       assert_eq!(route.hops[2].short_channel_id, 6);
+                       assert_eq!(route.hops[2].fee_msat, 0);
+                       assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
+
+                       assert_eq!(route.hops[3].pubkey, node4);
+                       assert_eq!(route.hops[3].short_channel_id, 11);
+                       assert_eq!(route.hops[3].fee_msat, 0);
+                       assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
+
+                       assert_eq!(route.hops[4].pubkey, node7);
+                       assert_eq!(route.hops[4].short_channel_id, 8);
+                       assert_eq!(route.hops[4].fee_msat, 100);
+                       assert_eq!(route.hops[4].cltv_expiry_delta, 42);
+               }
+
+               { // Simple test with outbound channel to 4 to test that last_hops and first_hops connect
+                       let our_chans = vec![channelmanager::ChannelDetails {
+                               channel_id: [0; 32],
+                               short_channel_id: Some(42),
+                               remote_network_id: node4.clone(),
+                               channel_value_satoshis: 0,
+                               user_id: 0,
+                               outbound_capacity_msat: 0,
+                               inbound_capacity_msat: 0,
+                               is_live: true,
+                       }];
+                       let route = router.get_route(&node7, Some(&our_chans), &last_hops, 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 2);
+
+                       assert_eq!(route.hops[0].pubkey, node4);
+                       assert_eq!(route.hops[0].short_channel_id, 42);
+                       assert_eq!(route.hops[0].fee_msat, 0);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (8 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node7);
+                       assert_eq!(route.hops[1].short_channel_id, 8);
+                       assert_eq!(route.hops[1].fee_msat, 100);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, 42);
+               }
+
+               last_hops[0].fee_base_msat = 1000;
+
+               { // Revert to via 6 as the fee on 8 goes up
+                       let route = router.get_route(&node7, None, &last_hops, 100, 42).unwrap();
+                       assert_eq!(route.hops.len(), 4);
+
+                       assert_eq!(route.hops[0].pubkey, node2);
+                       assert_eq!(route.hops[0].short_channel_id, 2);
+                       assert_eq!(route.hops[0].fee_msat, 200); // fee increased as its % of value transferred across node
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 4);
+                       assert_eq!(route.hops[1].fee_msat, 100);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, (7 << 8) | 1);
+
+                       assert_eq!(route.hops[2].pubkey, node6);
+                       assert_eq!(route.hops[2].short_channel_id, 7);
+                       assert_eq!(route.hops[2].fee_msat, 0);
+                       assert_eq!(route.hops[2].cltv_expiry_delta, (10 << 8) | 1);
+
+                       assert_eq!(route.hops[3].pubkey, node7);
+                       assert_eq!(route.hops[3].short_channel_id, 10);
+                       assert_eq!(route.hops[3].fee_msat, 100);
+                       assert_eq!(route.hops[3].cltv_expiry_delta, 42);
+               }
+
+               { // ...but still use 8 for larger payments as 6 has a variable feerate
+                       let route = router.get_route(&node7, None, &last_hops, 2000, 42).unwrap();
+                       assert_eq!(route.hops.len(), 5);
+
+                       assert_eq!(route.hops[0].pubkey, node2);
+                       assert_eq!(route.hops[0].short_channel_id, 2);
+                       assert_eq!(route.hops[0].fee_msat, 3000);
+                       assert_eq!(route.hops[0].cltv_expiry_delta, (4 << 8) | 1);
+
+                       assert_eq!(route.hops[1].pubkey, node3);
+                       assert_eq!(route.hops[1].short_channel_id, 4);
+                       assert_eq!(route.hops[1].fee_msat, 0);
+                       assert_eq!(route.hops[1].cltv_expiry_delta, (6 << 8) | 1);
+
+                       assert_eq!(route.hops[2].pubkey, node5);
+                       assert_eq!(route.hops[2].short_channel_id, 6);
+                       assert_eq!(route.hops[2].fee_msat, 0);
+                       assert_eq!(route.hops[2].cltv_expiry_delta, (11 << 8) | 1);
+
+                       assert_eq!(route.hops[3].pubkey, node4);
+                       assert_eq!(route.hops[3].short_channel_id, 11);
+                       assert_eq!(route.hops[3].fee_msat, 1000);
+                       assert_eq!(route.hops[3].cltv_expiry_delta, (8 << 8) | 1);
+
+                       assert_eq!(route.hops[4].pubkey, node7);
+                       assert_eq!(route.hops[4].short_channel_id, 8);
+                       assert_eq!(route.hops[4].fee_msat, 2000);
+                       assert_eq!(route.hops[4].cltv_expiry_delta, 42);
+               }
+
+               { // Test Router serialization/deserialization
+                       let mut w = TestVecWriter(Vec::new());
+                       let network = router.network_map.read().unwrap();
+                       assert!(!network.channels.is_empty());
+                       assert!(!network.nodes.is_empty());
+                       network.write(&mut w).unwrap();
+                       assert!(<NetworkMap>::read(&mut ::std::io::Cursor::new(&w.0)).unwrap() == *network);
+               }
+       }
+}