Collect all lightning std::sync imports under crate::sync
[rust-lightning] / lightning / src / routing / network_graph.rs
index 8754656f40551250070bbf4fd6042b9c714ba2b4..9e4813e9155926fac85b20d307af1bb9ac8a1dc8 100644 (file)
@@ -1,3 +1,12 @@
+// This file is Copyright its original authors, visible in version control
+// history.
+//
+// This file is licensed under the Apache License, Version 2.0 <LICENSE-APACHE
+// or http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
+// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your option.
+// You may not use this file except in accordance with one or both of these
+// licenses.
+
 //! The top-level network map tracking logic lives here.
 
 use bitcoin::secp256k1::key::PublicKey;
@@ -7,67 +16,130 @@ use bitcoin::secp256k1;
 use bitcoin::hashes::sha256d::Hash as Sha256dHash;
 use bitcoin::hashes::Hash;
 use bitcoin::blockdata::script::Builder;
+use bitcoin::blockdata::transaction::TxOut;
 use bitcoin::blockdata::opcodes;
+use bitcoin::hash_types::BlockHash;
 
-use chain::chaininterface::{ChainError, ChainWatchInterface};
+use chain;
+use chain::Access;
 use ln::features::{ChannelFeatures, NodeFeatures};
-use ln::msgs::{DecodeError, ErrorAction, LightningError, RoutingMessageHandler, NetAddress, OptionalField};
+use ln::msgs::{DecodeError, ErrorAction, Init, LightningError, RoutingMessageHandler, NetAddress, MAX_VALUE_MSAT};
+use ln::msgs::{ChannelAnnouncement, ChannelUpdate, NodeAnnouncement, OptionalField};
+use ln::msgs::{QueryChannelRange, ReplyChannelRange, QueryShortChannelIds, ReplyShortChannelIdsEnd};
 use ln::msgs;
 use util::ser::{Writeable, Readable, Writer};
-use util::logger::Logger;
-
-use std::{cmp, fmt};
-use std::sync::RwLock;
-use std::sync::atomic::{AtomicUsize, Ordering};
-use std::collections::BTreeMap;
-use std::collections::btree_map::Entry as BtreeEntry;
-use std::ops::Deref;
+use util::logger::{Logger, Level};
+use util::events::{MessageSendEvent, MessageSendEventsProvider};
+use util::scid_utils::{block_from_scid, scid_from_parts, MAX_SCID_BLOCK};
+
+use prelude::*;
+use alloc::collections::{BTreeMap, btree_map::Entry as BtreeEntry};
+use core::{cmp, fmt};
+use sync::{RwLock, RwLockReadGuard};
+use core::sync::atomic::{AtomicUsize, Ordering};
+use sync::Mutex;
+use core::ops::Deref;
 use bitcoin::hashes::hex::ToHex;
 
+/// The maximum number of extra bytes which we do not understand in a gossip message before we will
+/// refuse to relay the message.
+const MAX_EXCESS_BYTES_FOR_RELAY: usize = 1024;
+
+/// Maximum number of short_channel_ids that will be encoded in one gossip reply message.
+/// This value ensures a reply fits within the 65k payload limit and is consistent with other implementations.
+const MAX_SCIDS_PER_REPLY: usize = 8000;
+
+/// Represents the network as nodes and channels between them
+#[derive(Clone, PartialEq)]
+pub struct NetworkGraph {
+       genesis_hash: BlockHash,
+       channels: BTreeMap<u64, ChannelInfo>,
+       nodes: BTreeMap<PublicKey, NodeInfo>,
+}
+
+/// A simple newtype for RwLockReadGuard<'a, NetworkGraph>.
+/// This exists only to make accessing a RwLock<NetworkGraph> possible from
+/// the C bindings, as it can be done directly in Rust code.
+pub struct LockedNetworkGraph<'a>(pub RwLockReadGuard<'a, NetworkGraph>);
+
 /// Receives and validates network updates from peers,
 /// stores authentic and relevant data as a network graph.
 /// This network graph is then used for routing payments.
 /// Provides interface to help with initial routing sync by
 /// serving historical announcements.
-pub struct NetGraphMsgHandler<C: Deref, L: Deref> where C::Target: ChainWatchInterface, L::Target: Logger {
+pub struct NetGraphMsgHandler<C: Deref, L: Deref> where C::Target: chain::Access, L::Target: Logger {
        secp_ctx: Secp256k1<secp256k1::VerifyOnly>,
        /// Representation of the payment channel network
        pub network_graph: RwLock<NetworkGraph>,
-       chain_monitor: C,
+       chain_access: Option<C>,
        full_syncs_requested: AtomicUsize,
+       pending_events: Mutex<Vec<MessageSendEvent>>,
        logger: L,
 }
 
-impl<C: Deref, L: Deref> NetGraphMsgHandler<C, L> where C::Target: ChainWatchInterface, L::Target: Logger {
+impl<C: Deref, L: Deref> NetGraphMsgHandler<C, L> where C::Target: chain::Access, L::Target: Logger {
        /// Creates a new tracker of the actual state of the network of channels and nodes,
        /// assuming a fresh network graph.
        /// Chain monitor is used to make sure announced channels exist on-chain,
        /// channel data is correct, and that the announcement is signed with
        /// channel owners' keys.
-       pub fn new(chain_monitor: C, logger: L) -> Self {
+       pub fn new(genesis_hash: BlockHash, chain_access: Option<C>, logger: L) -> Self {
                NetGraphMsgHandler {
                        secp_ctx: Secp256k1::verification_only(),
-                       network_graph: RwLock::new(NetworkGraph {
-                               channels: BTreeMap::new(),
-                               nodes: BTreeMap::new(),
-                       }),
+                       network_graph: RwLock::new(NetworkGraph::new(genesis_hash)),
                        full_syncs_requested: AtomicUsize::new(0),
-                       chain_monitor,
+                       chain_access,
+                       pending_events: Mutex::new(vec![]),
                        logger,
                }
        }
 
        /// Creates a new tracker of the actual state of the network of channels and nodes,
        /// assuming an existing Network Graph.
-       pub fn from_net_graph(chain_monitor: C, logger: L, network_graph: NetworkGraph) -> Self {
+       pub fn from_net_graph(chain_access: Option<C>, logger: L, network_graph: NetworkGraph) -> Self {
                NetGraphMsgHandler {
                        secp_ctx: Secp256k1::verification_only(),
                        network_graph: RwLock::new(network_graph),
                        full_syncs_requested: AtomicUsize::new(0),
-                       chain_monitor,
+                       chain_access,
+                       pending_events: Mutex::new(vec![]),
                        logger,
                }
        }
+
+       /// Adds a provider used to check new announcements. Does not affect
+       /// existing announcements unless they are updated.
+       /// Add, update or remove the provider would replace the current one.
+       pub fn add_chain_access(&mut self, chain_access: Option<C>) {
+               self.chain_access = chain_access;
+       }
+
+       /// Take a read lock on the network_graph and return it in the C-bindings
+       /// newtype helper. This is likely only useful when called via the C
+       /// bindings as you can call `self.network_graph.read().unwrap()` in Rust
+       /// yourself.
+       pub fn read_locked_graph<'a>(&'a self) -> LockedNetworkGraph<'a> {
+               LockedNetworkGraph(self.network_graph.read().unwrap())
+       }
+
+       /// Returns true when a full routing table sync should be performed with a peer.
+       fn should_request_full_sync(&self, _node_id: &PublicKey) -> bool {
+               //TODO: Determine whether to request a full sync based on the network map.
+               const FULL_SYNCS_TO_REQUEST: usize = 5;
+               if self.full_syncs_requested.load(Ordering::Acquire) < FULL_SYNCS_TO_REQUEST {
+                       self.full_syncs_requested.fetch_add(1, Ordering::AcqRel);
+                       true
+               } else {
+                       false
+               }
+       }
+}
+
+impl<'a> LockedNetworkGraph<'a> {
+       /// Get a reference to the NetworkGraph which this read-lock contains.
+       pub fn graph(&self) -> &NetworkGraph {
+               &*self.0
+       }
 }
 
 
@@ -80,65 +152,44 @@ macro_rules! secp_verify_sig {
        };
 }
 
-impl<C: Deref + Sync + Send, L: Deref + Sync + Send> RoutingMessageHandler for NetGraphMsgHandler<C, L> where C::Target: ChainWatchInterface, L::Target: Logger {
+impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> where C::Target: chain::Access, L::Target: Logger {
        fn handle_node_announcement(&self, msg: &msgs::NodeAnnouncement) -> Result<bool, LightningError> {
-               self.network_graph.write().unwrap().update_node_from_announcement(msg, Some(&self.secp_ctx))
+               self.network_graph.write().unwrap().update_node_from_announcement(msg, &self.secp_ctx)?;
+               Ok(msg.contents.excess_data.len() <=  MAX_EXCESS_BYTES_FOR_RELAY &&
+                  msg.contents.excess_address_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY &&
+                  msg.contents.excess_data.len() + msg.contents.excess_address_data.len() <= MAX_EXCESS_BYTES_FOR_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".to_owned(), action: ErrorAction::IgnoreError});
-               }
-
-               let utxo_value = 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: format!("Channel announcement key ({}) didn't match on-chain script ({})", script_pubkey.to_hex(), expected_script.to_hex()), 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
-                               Some(value)
-                       },
-                       Err(ChainError::NotSupported) => {
-                               // Tentatively accept, potentially exposing us to DoS attacks
-                               None
-                       },
-                       Err(ChainError::NotWatched) => {
-                               return Err(LightningError{err: format!("Channel announced on an unknown chain ({})", msg.contents.chain_hash.encode().to_hex()), action: ErrorAction::IgnoreError});
-                       },
-                       Err(ChainError::UnknownTx) => {
-                               return Err(LightningError{err: "Channel announced without corresponding UTXO entry".to_owned(), action: ErrorAction::IgnoreError});
-                       },
-               };
-               let result = self.network_graph.write().unwrap().update_channel_from_announcement(msg, utxo_value, Some(&self.secp_ctx));
+               self.network_graph.write().unwrap().update_channel_from_announcement(msg, &self.chain_access, &self.secp_ctx)?;
                log_trace!(self.logger, "Added channel_announcement for {}{}", msg.contents.short_channel_id, if !msg.contents.excess_data.is_empty() { " with excess uninterpreted data!" } else { "" });
-               result
+               Ok(msg.contents.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY)
        }
 
        fn handle_htlc_fail_channel_update(&self, update: &msgs::HTLCFailChannelUpdate) {
                match update {
                        &msgs::HTLCFailChannelUpdate::ChannelUpdateMessage { ref msg } => {
-                               let _ = self.network_graph.write().unwrap().update_channel(msg, Some(&self.secp_ctx));
+                               let chan_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
+                               log_debug!(self.logger, "Updating channel with channel_update from a payment failure. Channel {} is {}abled.", msg.contents.short_channel_id, if chan_enabled { "en" } else { "dis" });
+                               let _ = self.network_graph.write().unwrap().update_channel(msg, &self.secp_ctx);
                        },
                        &msgs::HTLCFailChannelUpdate::ChannelClosed { short_channel_id, is_permanent } => {
+                               log_debug!(self.logger, "{} channel graph entry for {} due to a payment failure.", if is_permanent { "Removing" } else { "Disabling" }, short_channel_id);
                                self.network_graph.write().unwrap().close_channel_from_update(short_channel_id, is_permanent);
                        },
                        &msgs::HTLCFailChannelUpdate::NodeFailure { ref node_id, is_permanent } => {
+                               log_debug!(self.logger, "{} node graph entry for {} due to a payment failure.", if is_permanent { "Removing" } else { "Disabling" }, node_id);
                                self.network_graph.write().unwrap().fail_node(node_id, is_permanent);
                        },
                }
        }
 
        fn handle_channel_update(&self, msg: &msgs::ChannelUpdate) -> Result<bool, LightningError> {
-               self.network_graph.write().unwrap().update_channel(msg, Some(&self.secp_ctx))
+               self.network_graph.write().unwrap().update_channel(msg, &self.secp_ctx)?;
+               Ok(msg.contents.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY)
        }
 
-       fn get_next_channel_announcements(&self, starting_point: u64, batch_amount: u8) -> Vec<(msgs::ChannelAnnouncement, Option<msgs::ChannelUpdate>, Option<msgs::ChannelUpdate>)> {
+       fn get_next_channel_announcements(&self, starting_point: u64, batch_amount: u8) -> Vec<(ChannelAnnouncement, Option<ChannelUpdate>, Option<ChannelUpdate>)> {
                let network_graph = self.network_graph.read().unwrap();
                let mut result = Vec::with_capacity(batch_amount as usize);
                let mut iter = network_graph.get_channels().range(starting_point..);
@@ -166,7 +217,7 @@ impl<C: Deref + Sync + Send, L: Deref + Sync + Send> RoutingMessageHandler for N
                result
        }
 
-       fn get_next_node_announcements(&self, starting_point: Option<&PublicKey>, batch_amount: u8) -> Vec<msgs::NodeAnnouncement> {
+       fn get_next_node_announcements(&self, starting_point: Option<&PublicKey>, batch_amount: u8) -> Vec<NodeAnnouncement> {
                let network_graph = self.network_graph.read().unwrap();
                let mut result = Vec::with_capacity(batch_amount as usize);
                let mut iter = if let Some(pubkey) = starting_point {
@@ -190,19 +241,214 @@ impl<C: Deref + Sync + Send, L: Deref + Sync + Send> RoutingMessageHandler for N
                result
        }
 
-       fn should_request_full_sync(&self, _node_id: &PublicKey) -> bool {
-               //TODO: Determine whether to request a full sync based on the network map.
-               const FULL_SYNCS_TO_REQUEST: usize = 5;
-               if self.full_syncs_requested.load(Ordering::Acquire) < FULL_SYNCS_TO_REQUEST {
-                       self.full_syncs_requested.fetch_add(1, Ordering::AcqRel);
-                       true
-               } else {
-                       false
+       /// Initiates a stateless sync of routing gossip information with a peer
+       /// using gossip_queries. The default strategy used by this implementation
+       /// is to sync the full block range with several peers.
+       ///
+       /// We should expect one or more reply_channel_range messages in response
+       /// to our query_channel_range. Each reply will enqueue a query_scid message
+       /// to request gossip messages for each channel. The sync is considered complete
+       /// when the final reply_scids_end message is received, though we are not
+       /// tracking this directly.
+       fn sync_routing_table(&self, their_node_id: &PublicKey, init_msg: &Init) {
+
+               // We will only perform a sync with peers that support gossip_queries.
+               if !init_msg.features.supports_gossip_queries() {
+                       return ();
+               }
+
+               // Check if we need to perform a full synchronization with this peer
+               if !self.should_request_full_sync(their_node_id) {
+                       return ();
+               }
+
+               let first_blocknum = 0;
+               let number_of_blocks = 0xffffffff;
+               log_debug!(self.logger, "Sending query_channel_range peer={}, first_blocknum={}, number_of_blocks={}", log_pubkey!(their_node_id), first_blocknum, number_of_blocks);
+               let mut pending_events = self.pending_events.lock().unwrap();
+               pending_events.push(MessageSendEvent::SendChannelRangeQuery {
+                       node_id: their_node_id.clone(),
+                       msg: QueryChannelRange {
+                               chain_hash: self.network_graph.read().unwrap().genesis_hash,
+                               first_blocknum,
+                               number_of_blocks,
+                       },
+               });
+       }
+
+       /// Statelessly processes a reply to a channel range query by immediately
+       /// sending an SCID query with SCIDs in the reply. To keep this handler
+       /// stateless, it does not validate the sequencing of replies for multi-
+       /// reply ranges. It does not validate whether the reply(ies) cover the
+       /// queried range. It also does not filter SCIDs to only those in the
+       /// original query range. We also do not validate that the chain_hash
+       /// matches the chain_hash of the NetworkGraph. Any chan_ann message that
+       /// does not match our chain_hash will be rejected when the announcement is
+       /// processed.
+       fn handle_reply_channel_range(&self, their_node_id: &PublicKey, msg: ReplyChannelRange) -> Result<(), LightningError> {
+               log_debug!(self.logger, "Handling reply_channel_range peer={}, first_blocknum={}, number_of_blocks={}, sync_complete={}, scids={}", log_pubkey!(their_node_id), msg.first_blocknum, msg.number_of_blocks, msg.sync_complete, msg.short_channel_ids.len(),);
+
+               log_debug!(self.logger, "Sending query_short_channel_ids peer={}, batch_size={}", log_pubkey!(their_node_id), msg.short_channel_ids.len());
+               let mut pending_events = self.pending_events.lock().unwrap();
+               pending_events.push(MessageSendEvent::SendShortIdsQuery {
+                       node_id: their_node_id.clone(),
+                       msg: QueryShortChannelIds {
+                               chain_hash: msg.chain_hash,
+                               short_channel_ids: msg.short_channel_ids,
+                       }
+               });
+
+               Ok(())
+       }
+
+       /// When an SCID query is initiated the remote peer will begin streaming
+       /// gossip messages. In the event of a failure, we may have received
+       /// some channel information. Before trying with another peer, the
+       /// caller should update its set of SCIDs that need to be queried.
+       fn handle_reply_short_channel_ids_end(&self, their_node_id: &PublicKey, msg: ReplyShortChannelIdsEnd) -> Result<(), LightningError> {
+               log_debug!(self.logger, "Handling reply_short_channel_ids_end peer={}, full_information={}", log_pubkey!(their_node_id), msg.full_information);
+
+               // If the remote node does not have up-to-date information for the
+               // chain_hash they will set full_information=false. We can fail
+               // the result and try again with a different peer.
+               if !msg.full_information {
+                       return Err(LightningError {
+                               err: String::from("Received reply_short_channel_ids_end with no information"),
+                               action: ErrorAction::IgnoreError
+                       });
+               }
+
+               Ok(())
+       }
+
+       /// Processes a query from a peer by finding announced/public channels whose funding UTXOs
+       /// are in the specified block range. Due to message size limits, large range
+       /// queries may result in several reply messages. This implementation enqueues
+       /// all reply messages into pending events. Each message will allocate just under 65KiB. A full
+       /// sync of the public routing table with 128k channels will generated 16 messages and allocate ~1MB.
+       /// Logic can be changed to reduce allocation if/when a full sync of the routing table impacts
+       /// memory constrained systems.
+       fn handle_query_channel_range(&self, their_node_id: &PublicKey, msg: QueryChannelRange) -> Result<(), LightningError> {
+               log_debug!(self.logger, "Handling query_channel_range peer={}, first_blocknum={}, number_of_blocks={}", log_pubkey!(their_node_id), msg.first_blocknum, msg.number_of_blocks);
+
+               let network_graph = self.network_graph.read().unwrap();
+
+               let inclusive_start_scid = scid_from_parts(msg.first_blocknum as u64, 0, 0);
+
+               // We might receive valid queries with end_blocknum that would overflow SCID conversion.
+               // If so, we manually cap the ending block to avoid this overflow.
+               let exclusive_end_scid = scid_from_parts(cmp::min(msg.end_blocknum() as u64, MAX_SCID_BLOCK), 0, 0);
+
+               // Per spec, we must reply to a query. Send an empty message when things are invalid.
+               if msg.chain_hash != network_graph.genesis_hash || inclusive_start_scid.is_err() || exclusive_end_scid.is_err() || msg.number_of_blocks == 0 {
+                       let mut pending_events = self.pending_events.lock().unwrap();
+                       pending_events.push(MessageSendEvent::SendReplyChannelRange {
+                               node_id: their_node_id.clone(),
+                               msg: ReplyChannelRange {
+                                       chain_hash: msg.chain_hash.clone(),
+                                       first_blocknum: msg.first_blocknum,
+                                       number_of_blocks: msg.number_of_blocks,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![],
+                               }
+                       });
+                       return Err(LightningError {
+                               err: String::from("query_channel_range could not be processed"),
+                               action: ErrorAction::IgnoreError,
+                       });
+               }
+
+               // Creates channel batches. We are not checking if the channel is routable
+               // (has at least one update). A peer may still want to know the channel
+               // exists even if its not yet routable.
+               let mut batches: Vec<Vec<u64>> = vec![Vec::with_capacity(MAX_SCIDS_PER_REPLY)];
+               for (_, ref chan) in network_graph.get_channels().range(inclusive_start_scid.unwrap()..exclusive_end_scid.unwrap()) {
+                       if let Some(chan_announcement) = &chan.announcement_message {
+                               // Construct a new batch if last one is full
+                               if batches.last().unwrap().len() == batches.last().unwrap().capacity() {
+                                       batches.push(Vec::with_capacity(MAX_SCIDS_PER_REPLY));
+                               }
+
+                               let batch = batches.last_mut().unwrap();
+                               batch.push(chan_announcement.contents.short_channel_id);
+                       }
+               }
+               drop(network_graph);
+
+               let mut pending_events = self.pending_events.lock().unwrap();
+               let batch_count = batches.len();
+               let mut prev_batch_endblock = msg.first_blocknum;
+               for (batch_index, batch) in batches.into_iter().enumerate() {
+                       // Per spec, the initial `first_blocknum` needs to be <= the query's `first_blocknum`
+                       // and subsequent `first_blocknum`s must be >= the prior reply's `first_blocknum`.
+                       //
+                       // Additionally, c-lightning versions < 0.10 require that the `first_blocknum` of each
+                       // reply is >= the previous reply's `first_blocknum` and either exactly the previous
+                       // reply's `first_blocknum + number_of_blocks` or exactly one greater. This is a
+                       // significant diversion from the requirements set by the spec, and, in case of blocks
+                       // with no channel opens (e.g. empty blocks), requires that we use the previous value
+                       // and *not* derive the first_blocknum from the actual first block of the reply.
+                       let first_blocknum = prev_batch_endblock;
+
+                       // Each message carries the number of blocks (from the `first_blocknum`) its contents
+                       // fit in. Though there is no requirement that we use exactly the number of blocks its
+                       // contents are from, except for the bogus requirements c-lightning enforces, above.
+                       //
+                       // Per spec, the last end block (ie `first_blocknum + number_of_blocks`) needs to be
+                       // >= the query's end block. Thus, for the last reply, we calculate the difference
+                       // between the query's end block and the start of the reply.
+                       //
+                       // Overflow safe since end_blocknum=msg.first_block_num+msg.number_of_blocks and
+                       // first_blocknum will be either msg.first_blocknum or a higher block height.
+                       let (sync_complete, number_of_blocks) = if batch_index == batch_count-1 {
+                               (true, msg.end_blocknum() - first_blocknum)
+                       }
+                       // Prior replies should use the number of blocks that fit into the reply. Overflow
+                       // safe since first_blocknum is always <= last SCID's block.
+                       else {
+                               (false, block_from_scid(batch.last().unwrap()) - first_blocknum)
+                       };
+
+                       prev_batch_endblock = first_blocknum + number_of_blocks;
+
+                       pending_events.push(MessageSendEvent::SendReplyChannelRange {
+                               node_id: their_node_id.clone(),
+                               msg: ReplyChannelRange {
+                                       chain_hash: msg.chain_hash.clone(),
+                                       first_blocknum,
+                                       number_of_blocks,
+                                       sync_complete,
+                                       short_channel_ids: batch,
+                               }
+                       });
                }
+
+               Ok(())
+       }
+
+       fn handle_query_short_channel_ids(&self, _their_node_id: &PublicKey, _msg: QueryShortChannelIds) -> Result<(), LightningError> {
+               // TODO
+               Err(LightningError {
+                       err: String::from("Not implemented"),
+                       action: ErrorAction::IgnoreError,
+               })
+       }
+}
+
+impl<C: Deref, L: Deref> MessageSendEventsProvider for NetGraphMsgHandler<C, L>
+where
+       C::Target: chain::Access,
+       L::Target: Logger,
+{
+       fn get_and_clear_pending_msg_events(&self) -> Vec<MessageSendEvent> {
+               let mut ret = Vec::new();
+               let mut pending_events = self.pending_events.lock().unwrap();
+               core::mem::swap(&mut ret, &mut pending_events);
+               ret
        }
 }
 
-#[derive(PartialEq, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 /// Details about one direction of a channel. Received
 /// within a channel update.
 pub struct DirectionalChannelInfo {
@@ -223,7 +469,7 @@ pub struct DirectionalChannelInfo {
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
-       pub last_update_message: Option<msgs::ChannelUpdate>,
+       pub last_update_message: Option<ChannelUpdate>,
 }
 
 impl fmt::Display for DirectionalChannelInfo {
@@ -233,17 +479,17 @@ impl fmt::Display for DirectionalChannelInfo {
        }
 }
 
-impl_writeable!(DirectionalChannelInfo, 0, {
-       last_update,
-       enabled,
-       cltv_expiry_delta,
-       htlc_minimum_msat,
-       htlc_maximum_msat,
-       fees,
-       last_update_message
+impl_writeable_tlv_based!(DirectionalChannelInfo, {
+       (0, last_update, required),
+       (2, enabled, required),
+       (4, cltv_expiry_delta, required),
+       (6, htlc_minimum_msat, required),
+       (8, htlc_maximum_msat, required),
+       (10, fees, required),
+       (12, last_update_message, required),
 });
 
-#[derive(PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 /// Details about a channel (both directions).
 /// Received within a channel announcement.
 pub struct ChannelInfo {
@@ -263,7 +509,7 @@ pub struct ChannelInfo {
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
-       pub announcement_message: Option<msgs::ChannelAnnouncement>,
+       pub announcement_message: Option<ChannelAnnouncement>,
 }
 
 impl fmt::Display for ChannelInfo {
@@ -274,14 +520,14 @@ impl fmt::Display for ChannelInfo {
        }
 }
 
-impl_writeable!(ChannelInfo, 0, {
-       features,
-       node_one,
-       one_to_two,
-       node_two,
-       two_to_one,
-       capacity_sats,
-       announcement_message
+impl_writeable_tlv_based!(ChannelInfo, {
+       (0, features, required),
+       (2, node_one, required),
+       (4, one_to_two, required),
+       (6, node_two, required),
+       (8, two_to_one, required),
+       (10, capacity_sats, required),
+       (12, announcement_message, required),
 });
 
 
@@ -295,26 +541,12 @@ pub struct RoutingFees {
        pub proportional_millionths: u32,
 }
 
-impl Readable for RoutingFees{
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<RoutingFees, DecodeError> {
-               let base_msat: u32 = Readable::read(reader)?;
-               let proportional_millionths: u32 = Readable::read(reader)?;
-               Ok(RoutingFees {
-                       base_msat,
-                       proportional_millionths,
-               })
-       }
-}
-
-impl Writeable for RoutingFees {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
-               self.base_msat.write(writer)?;
-               self.proportional_millionths.write(writer)?;
-               Ok(())
-       }
-}
+impl_writeable_tlv_based!(RoutingFees, {
+       (0, base_msat, required),
+       (2, proportional_millionths, required)
+});
 
-#[derive(PartialEq, Debug)]
+#[derive(Clone, Debug, PartialEq)]
 /// Information received in the latest node_announcement from this node.
 pub struct NodeAnnouncementInfo {
        /// Protocol features the node announced support for
@@ -334,53 +566,19 @@ pub struct NodeAnnouncementInfo {
        /// Mostly redundant with the data we store in fields explicitly.
        /// Everything else is useful only for sending out for initial routing sync.
        /// Not stored if contains excess data to prevent DoS.
-       pub announcement_message: Option<msgs::NodeAnnouncement>
+       pub announcement_message: Option<NodeAnnouncement>
 }
 
-impl Writeable for NodeAnnouncementInfo {
-       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
-               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(())
-       }
-}
-
-impl Readable for NodeAnnouncementInfo {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NodeAnnouncementInfo, DecodeError> {
-               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(NodeAnnouncementInfo {
-                       features,
-                       last_update,
-                       rgb,
-                       alias,
-                       addresses,
-                       announcement_message
-               })
-       }
-}
+impl_writeable_tlv_based!(NodeAnnouncementInfo, {
+       (0, features, required),
+       (2, last_update, required),
+       (4, rgb, required),
+       (6, alias, required),
+       (8, announcement_message, option),
+       (10, addresses, vec_type),
+});
 
-#[derive(PartialEq)]
+#[derive(Clone, Debug, PartialEq)]
 /// Details about a node in the network, known from the network announcement.
 pub struct NodeInfo {
        /// All valid channels a node has announced
@@ -403,46 +601,20 @@ impl fmt::Display for NodeInfo {
        }
 }
 
-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_fees.write(writer)?;
-               self.announcement_info.write(writer)?;
-               Ok(())
-       }
-}
-
-const MAX_ALLOC_SIZE: u64 = 64*1024;
-
-impl Readable for NodeInfo {
-       fn read<R: ::std::io::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_fees = Readable::read(reader)?;
-               let announcement_info = Readable::read(reader)?;
-               Ok(NodeInfo {
-                       channels,
-                       lowest_inbound_channel_fees,
-                       announcement_info,
-               })
-       }
-}
+impl_writeable_tlv_based!(NodeInfo, {
+       (0, lowest_inbound_channel_fees, option),
+       (2, announcement_info, option),
+       (4, channels, vec_type),
+});
 
-/// Represents the network as nodes and channels between them
-#[derive(PartialEq)]
-pub struct NetworkGraph {
-       channels: BTreeMap<u64, ChannelInfo>,
-       nodes: BTreeMap<PublicKey, NodeInfo>,
-}
+const SERIALIZATION_VERSION: u8 = 1;
+const MIN_SERIALIZATION_VERSION: u8 = 1;
 
 impl Writeable for NetworkGraph {
        fn write<W: Writer>(&self, writer: &mut W) -> Result<(), ::std::io::Error> {
+               write_ver_prefix!(writer, SERIALIZATION_VERSION, MIN_SERIALIZATION_VERSION);
+
+               self.genesis_hash.write(writer)?;
                (self.channels.len() as u64).write(writer)?;
                for (ref chan_id, ref chan_info) in self.channels.iter() {
                        (*chan_id).write(writer)?;
@@ -453,12 +625,17 @@ impl Writeable for NetworkGraph {
                        node_id.write(writer)?;
                        node_info.write(writer)?;
                }
+
+               write_tlv_fields!(writer, {});
                Ok(())
        }
 }
 
 impl Readable for NetworkGraph {
        fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NetworkGraph, DecodeError> {
+               let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
+
+               let genesis_hash: BlockHash = Readable::read(reader)?;
                let channels_count: u64 = Readable::read(reader)?;
                let mut channels = BTreeMap::new();
                for _ in 0..channels_count {
@@ -473,7 +650,10 @@ impl Readable for NetworkGraph {
                        let node_info = Readable::read(reader)?;
                        nodes.insert(node_id, node_info);
                }
+               read_tlv_fields!(reader, {});
+
                Ok(NetworkGraph {
+                       genesis_hash,
                        channels,
                        nodes,
                })
@@ -482,13 +662,13 @@ impl Readable for NetworkGraph {
 
 impl fmt::Display for NetworkGraph {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-               write!(f, "Network map\n[Channels]\n")?;
+               writeln!(f, "Network map\n[Channels]")?;
                for (key, val) in self.channels.iter() {
-                       write!(f, " {}: {}\n", key, val)?;
+                       writeln!(f, " {}: {}", key, val)?;
                }
-               write!(f, "[Nodes]\n")?;
+               writeln!(f, "[Nodes]")?;
                for (key, val) in self.nodes.iter() {
-                       write!(f, " {}: {}\n", log_pubkey!(key), val)?;
+                       writeln!(f, " {}: {}", log_pubkey!(key), val)?;
                }
                Ok(())
        }
@@ -496,13 +676,19 @@ impl fmt::Display for NetworkGraph {
 
 impl NetworkGraph {
        /// Returns all known valid channels' short ids along with announced channel info.
+       ///
+       /// (C-not exported) because we have no mapping for `BTreeMap`s
        pub fn get_channels<'a>(&'a self) -> &'a BTreeMap<u64, ChannelInfo> { &self.channels }
        /// Returns all known nodes' public keys along with announced node info.
+       ///
+       /// (C-not exported) because we have no mapping for `BTreeMap`s
        pub fn get_nodes<'a>(&'a self) -> &'a BTreeMap<PublicKey, NodeInfo> { &self.nodes }
 
        /// Get network addresses by node id.
        /// Returns None if the requested node is completely unknown,
        /// or if node announcement for the node was never received.
+       ///
+       /// (C-not exported) as there is no practical way to track lifetimes of returned values.
        pub fn get_addresses<'a>(&'a self, pubkey: &PublicKey) -> Option<&'a Vec<NetAddress>> {
                if let Some(node) = self.nodes.get(pubkey) {
                        if let Some(node_info) = node.announcement_info.as_ref() {
@@ -513,73 +699,145 @@ impl NetworkGraph {
        }
 
        /// Creates a new, empty, network graph.
-       pub fn new() -> NetworkGraph {
+       pub fn new(genesis_hash: BlockHash) -> NetworkGraph {
                Self {
+                       genesis_hash,
                        channels: BTreeMap::new(),
                        nodes: BTreeMap::new(),
                }
        }
 
-       /// For an already known node (from channel announcements), update its stored properties from a given node announcement
-       /// Announcement signatures are checked here only if Secp256k1 object is provided.
-       fn update_node_from_announcement(&mut self, msg: &msgs::NodeAnnouncement, secp_ctx: Option<&Secp256k1<secp256k1::VerifyOnly>>) -> Result<bool, LightningError> {
-               if let Some(sig_verifier) = secp_ctx {
-                       let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
-                       secp_verify_sig!(sig_verifier, &msg_hash, &msg.signature, &msg.contents.node_id);
-               }
+       /// For an already known node (from channel announcements), update its stored properties from a
+       /// given node announcement.
+       ///
+       /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
+       /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
+       /// routing messages from a source using a protocol other than the lightning P2P protocol.
+       pub fn update_node_from_announcement<T: secp256k1::Verification>(&mut self, msg: &msgs::NodeAnnouncement, secp_ctx: &Secp256k1<T>) -> Result<(), LightningError> {
+               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
+               secp_verify_sig!(secp_ctx, &msg_hash, &msg.signature, &msg.contents.node_id);
+               self.update_node_from_announcement_intern(&msg.contents, Some(&msg))
+       }
+
+       /// For an already known node (from channel announcements), update its stored properties from a
+       /// given node announcement without verifying the associated signatures. Because we aren't
+       /// given the associated signatures here we cannot relay the node announcement to any of our
+       /// peers.
+       pub fn update_node_from_unsigned_announcement(&mut self, msg: &msgs::UnsignedNodeAnnouncement) -> Result<(), LightningError> {
+               self.update_node_from_announcement_intern(msg, None)
+       }
 
-               match self.nodes.get_mut(&msg.contents.node_id) {
+       fn update_node_from_announcement_intern(&mut self, msg: &msgs::UnsignedNodeAnnouncement, full_msg: Option<&msgs::NodeAnnouncement>) -> Result<(), LightningError> {
+               match self.nodes.get_mut(&msg.node_id) {
                        None => Err(LightningError{err: "No existing channels for node_announcement".to_owned(), action: ErrorAction::IgnoreError}),
                        Some(node) => {
                                if let Some(node_info) = node.announcement_info.as_ref() {
-                                       if node_info.last_update  >= msg.contents.timestamp {
-                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
+                                       if node_info.last_update  >= msg.timestamp {
+                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Trace)});
                                        }
                                }
 
-                               let should_relay = msg.contents.excess_data.is_empty() && msg.contents.excess_address_data.is_empty();
+                               let should_relay =
+                                       msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY &&
+                                       msg.excess_address_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY &&
+                                       msg.excess_data.len() + msg.excess_address_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY;
                                node.announcement_info = Some(NodeAnnouncementInfo {
-                                       features: msg.contents.features.clone(),
-                                       last_update: msg.contents.timestamp,
-                                       rgb: msg.contents.rgb,
-                                       alias: msg.contents.alias,
-                                       addresses: msg.contents.addresses.clone(),
-                                       announcement_message: if should_relay { Some(msg.clone()) } else { None },
+                                       features: msg.features.clone(),
+                                       last_update: msg.timestamp,
+                                       rgb: msg.rgb,
+                                       alias: msg.alias,
+                                       addresses: msg.addresses.clone(),
+                                       announcement_message: if should_relay { full_msg.cloned() } else { None },
                                });
 
-                               Ok(should_relay)
+                               Ok(())
                        }
                }
        }
 
-       /// For a new or already known (from previous announcement) channel, store or update channel info.
-       /// Also store nodes (if not stored yet) the channel is between, and make node aware of this channel.
-       /// Checking utxo on-chain is useful if we receive an update for already known channel id,
-       /// which is probably result of a reorg. In that case, we update channel info only if the
-       /// utxo was checked, otherwise stick to the existing update, to prevent DoS risks.
-       /// Announcement signatures are checked here only if Secp256k1 object is provided.
-       fn update_channel_from_announcement(&mut self, msg: &msgs::ChannelAnnouncement, utxo_value: Option<u64>, secp_ctx: Option<&Secp256k1<secp256k1::VerifyOnly>>) -> Result<bool, LightningError> {
-               if let Some(sig_verifier) = secp_ctx {
-                       let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
-                       secp_verify_sig!(sig_verifier, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
-                       secp_verify_sig!(sig_verifier, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
-                       secp_verify_sig!(sig_verifier, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
-                       secp_verify_sig!(sig_verifier, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
+       /// Store or update channel info from a channel announcement.
+       ///
+       /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
+       /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
+       /// routing messages from a source using a protocol other than the lightning P2P protocol.
+       ///
+       /// If a `chain::Access` object is provided via `chain_access`, it will be called to verify
+       /// the corresponding UTXO exists on chain and is correctly-formatted.
+       pub fn update_channel_from_announcement<T: secp256k1::Verification, C: Deref>
+                       (&mut self, msg: &msgs::ChannelAnnouncement, chain_access: &Option<C>, secp_ctx: &Secp256k1<T>)
+                       -> Result<(), LightningError>
+                       where C::Target: chain::Access {
+               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
+               secp_verify_sig!(secp_ctx, &msg_hash, &msg.node_signature_1, &msg.contents.node_id_1);
+               secp_verify_sig!(secp_ctx, &msg_hash, &msg.node_signature_2, &msg.contents.node_id_2);
+               secp_verify_sig!(secp_ctx, &msg_hash, &msg.bitcoin_signature_1, &msg.contents.bitcoin_key_1);
+               secp_verify_sig!(secp_ctx, &msg_hash, &msg.bitcoin_signature_2, &msg.contents.bitcoin_key_2);
+               self.update_channel_from_unsigned_announcement_intern(&msg.contents, Some(msg), chain_access)
+       }
+
+       /// Store or update channel info from a channel announcement without verifying the associated
+       /// signatures. Because we aren't given the associated signatures here we cannot relay the
+       /// channel announcement to any of our peers.
+       ///
+       /// If a `chain::Access` object is provided via `chain_access`, it will be called to verify
+       /// the corresponding UTXO exists on chain and is correctly-formatted.
+       pub fn update_channel_from_unsigned_announcement<C: Deref>
+                       (&mut self, msg: &msgs::UnsignedChannelAnnouncement, chain_access: &Option<C>)
+                       -> Result<(), LightningError>
+                       where C::Target: chain::Access {
+               self.update_channel_from_unsigned_announcement_intern(msg, None, chain_access)
+       }
+
+       fn update_channel_from_unsigned_announcement_intern<C: Deref>
+                       (&mut self, msg: &msgs::UnsignedChannelAnnouncement, full_msg: Option<&msgs::ChannelAnnouncement>, chain_access: &Option<C>)
+                       -> Result<(), LightningError>
+                       where C::Target: chain::Access {
+               if msg.node_id_1 == msg.node_id_2 || msg.bitcoin_key_1 == msg.bitcoin_key_2 {
+                       return Err(LightningError{err: "Channel announcement node had a channel with itself".to_owned(), action: ErrorAction::IgnoreError});
                }
 
-               let should_relay = msg.contents.excess_data.is_empty();
+               let utxo_value = match &chain_access {
+                       &None => {
+                               // Tentatively accept, potentially exposing us to DoS attacks
+                               None
+                       },
+                       &Some(ref chain_access) => {
+                               match chain_access.get_utxo(&msg.chain_hash, msg.short_channel_id) {
+                                       Ok(TxOut { value, script_pubkey }) => {
+                                               let expected_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
+                                                                                   .push_slice(&msg.bitcoin_key_1.serialize())
+                                                                                   .push_slice(&msg.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: format!("Channel announcement key ({}) didn't match on-chain script ({})", script_pubkey.to_hex(), expected_script.to_hex()), 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
+                                               Some(value)
+                                       },
+                                       Err(chain::AccessError::UnknownChain) => {
+                                               return Err(LightningError{err: format!("Channel announced on an unknown chain ({})", msg.chain_hash.encode().to_hex()), action: ErrorAction::IgnoreError});
+                                       },
+                                       Err(chain::AccessError::UnknownTx) => {
+                                               return Err(LightningError{err: "Channel announced without corresponding UTXO entry".to_owned(), action: ErrorAction::IgnoreError});
+                                       },
+                               }
+                       },
+               };
 
                let chan_info = ChannelInfo {
-                               features: msg.contents.features.clone(),
-                               node_one: msg.contents.node_id_1.clone(),
+                               features: msg.features.clone(),
+                               node_one: msg.node_id_1.clone(),
                                one_to_two: None,
-                               node_two: msg.contents.node_id_2.clone(),
+                               node_two: msg.node_id_2.clone(),
                                two_to_one: None,
                                capacity_sats: utxo_value,
-                               announcement_message: if should_relay { Some(msg.clone()) } else { None },
+                               announcement_message: if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
+                                       { full_msg.cloned() } else { None },
                        };
 
-               match self.channels.entry(msg.contents.short_channel_id) {
+               match self.channels.entry(msg.short_channel_id) {
                        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
@@ -593,10 +851,10 @@ impl NetworkGraph {
                                        // 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(&mut self.nodes, &entry.get(), msg.contents.short_channel_id);
+                                       Self::remove_channel_in_nodes(&mut self.nodes, &entry.get(), msg.short_channel_id);
                                        *entry.get_mut() = chan_info;
                                } else {
-                                       return Err(LightningError{err: "Already have knowledge of channel".to_owned(), action: ErrorAction::IgnoreError})
+                                       return Err(LightningError{err: "Already have knowledge of channel".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Trace)})
                                }
                        },
                        BtreeEntry::Vacant(entry) => {
@@ -608,11 +866,11 @@ impl NetworkGraph {
                        ( $node_id: expr ) => {
                                match self.nodes.entry($node_id) {
                                        BtreeEntry::Occupied(node_entry) => {
-                                               node_entry.into_mut().channels.push(msg.contents.short_channel_id);
+                                               node_entry.into_mut().channels.push(msg.short_channel_id);
                                        },
                                        BtreeEntry::Vacant(node_entry) => {
                                                node_entry.insert(NodeInfo {
-                                                       channels: vec!(msg.contents.short_channel_id),
+                                                       channels: vec!(msg.short_channel_id),
                                                        lowest_inbound_channel_fees: None,
                                                        announcement_info: None,
                                                });
@@ -621,10 +879,10 @@ impl NetworkGraph {
                        };
                }
 
-               add_channel_to_node!(msg.contents.node_id_1);
-               add_channel_to_node!(msg.contents.node_id_2);
+               add_channel_to_node!(msg.node_id_1);
+               add_channel_to_node!(msg.node_id_2);
 
-               Ok(should_relay)
+               Ok(())
        }
 
        /// Close a channel if a corresponding HTLC fail was sent.
@@ -656,42 +914,67 @@ impl NetworkGraph {
                }
        }
 
-       /// For an already known (from announcement) channel, update info about one of the directions of a channel.
-       /// Announcement signatures are checked here only if Secp256k1 object is provided.
-       fn update_channel(&mut self, msg: &msgs::ChannelUpdate, secp_ctx: Option<&Secp256k1<secp256k1::VerifyOnly>>) -> Result<bool, LightningError> {
+       /// For an already known (from announcement) channel, update info about one of the directions
+       /// of the channel.
+       ///
+       /// You probably don't want to call this directly, instead relying on a NetGraphMsgHandler's
+       /// RoutingMessageHandler implementation to call it indirectly. This may be useful to accept
+       /// routing messages from a source using a protocol other than the lightning P2P protocol.
+       pub fn update_channel<T: secp256k1::Verification>(&mut self, msg: &msgs::ChannelUpdate, secp_ctx: &Secp256k1<T>) -> Result<(), LightningError> {
+               self.update_channel_intern(&msg.contents, Some(&msg), Some((&msg.signature, secp_ctx)))
+       }
+
+       /// For an already known (from announcement) channel, update info about one of the directions
+       /// of the channel without verifying the associated signatures. Because we aren't given the
+       /// associated signatures here we cannot relay the channel update to any of our peers.
+       pub fn update_channel_unsigned(&mut self, msg: &msgs::UnsignedChannelUpdate) -> Result<(), LightningError> {
+               self.update_channel_intern(msg, None, None::<(&secp256k1::Signature, &Secp256k1<secp256k1::VerifyOnly>)>)
+       }
+
+       fn update_channel_intern<T: secp256k1::Verification>(&mut self, msg: &msgs::UnsignedChannelUpdate, full_msg: Option<&msgs::ChannelUpdate>, sig_info: Option<(&secp256k1::Signature, &Secp256k1<T>)>) -> Result<(), LightningError> {
                let dest_node_id;
-               let chan_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
+               let chan_enabled = msg.flags & (1 << 1) != (1 << 1);
                let chan_was_enabled;
 
-               match self.channels.get_mut(&msg.contents.short_channel_id) {
+               match self.channels.get_mut(&msg.short_channel_id) {
                        None => return Err(LightningError{err: "Couldn't find channel for update".to_owned(), action: ErrorAction::IgnoreError}),
                        Some(channel) => {
+                               if let OptionalField::Present(htlc_maximum_msat) = msg.htlc_maximum_msat {
+                                       if htlc_maximum_msat > MAX_VALUE_MSAT {
+                                               return Err(LightningError{err: "htlc_maximum_msat is larger than maximum possible msats".to_owned(), action: ErrorAction::IgnoreError});
+                                       }
+
+                                       if let Some(capacity_sats) = channel.capacity_sats {
+                                               // It's possible channel capacity is available now, although it wasn't available at announcement (so the field is None).
+                                               // Don't query UTXO set here to reduce DoS risks.
+                                               if capacity_sats > MAX_VALUE_MSAT / 1000 || htlc_maximum_msat > capacity_sats * 1000 {
+                                                       return Err(LightningError{err: "htlc_maximum_msat is larger than channel capacity or capacity is bogus".to_owned(), action: ErrorAction::IgnoreError});
+                                               }
+                                       }
+                               }
                                macro_rules! maybe_update_channel_info {
                                        ( $target: expr, $src_node: expr) => {
                                                if let Some(existing_chan_info) = $target.as_ref() {
-                                                       if existing_chan_info.last_update >= msg.contents.timestamp {
-                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
+                                                       if existing_chan_info.last_update >= msg.timestamp {
+                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Trace)});
                                                        }
                                                        chan_was_enabled = existing_chan_info.enabled;
                                                } else {
                                                        chan_was_enabled = false;
                                                }
 
-                                               let last_update_message = if msg.contents.excess_data.is_empty() {
-                                                       Some(msg.clone())
-                                               } else {
-                                                       None
-                                               };
+                                               let last_update_message = if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
+                                                       { full_msg.cloned() } else { None };
 
                                                let updated_channel_dir_info = DirectionalChannelInfo {
                                                        enabled: chan_enabled,
-                                                       last_update: msg.contents.timestamp,
-                                                       cltv_expiry_delta: msg.contents.cltv_expiry_delta,
-                                                       htlc_minimum_msat: msg.contents.htlc_minimum_msat,
-                                                       htlc_maximum_msat: if let OptionalField::Present(max_value) = msg.contents.htlc_maximum_msat { Some(max_value) } else { None },
+                                                       last_update: msg.timestamp,
+                                                       cltv_expiry_delta: msg.cltv_expiry_delta,
+                                                       htlc_minimum_msat: msg.htlc_minimum_msat,
+                                                       htlc_maximum_msat: if let OptionalField::Present(max_value) = msg.htlc_maximum_msat { Some(max_value) } else { None },
                                                        fees: RoutingFees {
-                                                               base_msat: msg.contents.fee_base_msat,
-                                                               proportional_millionths: msg.contents.fee_proportional_millionths,
+                                                               base_msat: msg.fee_base_msat,
+                                                               proportional_millionths: msg.fee_proportional_millionths,
                                                        },
                                                        last_update_message
                                                };
@@ -699,17 +982,17 @@ impl NetworkGraph {
                                        }
                                }
 
-                               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.contents.encode()[..])[..]);
-                               if msg.contents.flags & 1 == 1 {
+                               let msg_hash = hash_to_message!(&Sha256dHash::hash(&msg.encode()[..])[..]);
+                               if msg.flags & 1 == 1 {
                                        dest_node_id = channel.node_one.clone();
-                                       if let Some(sig_verifier) = secp_ctx {
-                                               secp_verify_sig!(sig_verifier, &msg_hash, &msg.signature, &channel.node_two);
+                                       if let Some((sig, ctx)) = sig_info {
+                                               secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_two);
                                        }
                                        maybe_update_channel_info!(channel.two_to_one, channel.node_two);
                                } else {
                                        dest_node_id = channel.node_two.clone();
-                                       if let Some(sig_verifier) = secp_ctx {
-                                               secp_verify_sig!(sig_verifier, &msg_hash, &msg.signature, &channel.node_one);
+                                       if let Some((sig, ctx)) = sig_info {
+                                               secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_one);
                                        }
                                        maybe_update_channel_info!(channel.one_to_two, channel.node_one);
                                }
@@ -718,8 +1001,8 @@ impl NetworkGraph {
 
                if chan_enabled {
                        let node = self.nodes.get_mut(&dest_node_id).unwrap();
-                       let mut base_msat = msg.contents.fee_base_msat;
-                       let mut proportional_millionths = msg.contents.fee_proportional_millionths;
+                       let mut base_msat = msg.fee_base_msat;
+                       let mut proportional_millionths = msg.fee_proportional_millionths;
                        if let Some(fees) = node.lowest_inbound_channel_fees {
                                base_msat = cmp::min(base_msat, fees.base_msat);
                                proportional_millionths = cmp::min(proportional_millionths, fees.proportional_millionths);
@@ -753,7 +1036,7 @@ impl NetworkGraph {
                        node.lowest_inbound_channel_fees = lowest_inbound_channel_fees;
                }
 
-               Ok(msg.contents.excess_data.is_empty())
+               Ok(())
        }
 
        fn remove_channel_in_nodes(nodes: &mut BTreeMap<PublicKey, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
@@ -779,35 +1062,39 @@ impl NetworkGraph {
 
 #[cfg(test)]
 mod tests {
-       use chain::chaininterface;
-       use ln::features::{ChannelFeatures, NodeFeatures};
-       use routing::network_graph::{NetGraphMsgHandler, NetworkGraph};
-       use ln::msgs::{OptionalField, RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
-               UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate, HTLCFailChannelUpdate};
+       use chain;
+       use ln::features::{ChannelFeatures, InitFeatures, NodeFeatures};
+       use routing::network_graph::{NetGraphMsgHandler, NetworkGraph, MAX_EXCESS_BYTES_FOR_RELAY};
+       use ln::msgs::{Init, OptionalField, RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
+               UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate, HTLCFailChannelUpdate,
+               ReplyChannelRange, ReplyShortChannelIdsEnd, QueryChannelRange, QueryShortChannelIds, MAX_VALUE_MSAT};
        use util::test_utils;
        use util::logger::Logger;
        use util::ser::{Readable, Writeable};
+       use util::events::{MessageSendEvent, MessageSendEventsProvider};
+       use util::scid_utils::scid_from_parts;
 
        use bitcoin::hashes::sha256d::Hash as Sha256dHash;
        use bitcoin::hashes::Hash;
        use bitcoin::network::constants::Network;
        use bitcoin::blockdata::constants::genesis_block;
        use bitcoin::blockdata::script::Builder;
+       use bitcoin::blockdata::transaction::TxOut;
        use bitcoin::blockdata::opcodes;
-       use bitcoin::util::hash::BitcoinHash;
 
        use hex;
 
        use bitcoin::secp256k1::key::{PublicKey, SecretKey};
        use bitcoin::secp256k1::{All, Secp256k1};
 
-       use std::sync::Arc;
+       use prelude::*;
+       use sync::Arc;
 
-       fn create_net_graph_msg_handler() -> (Secp256k1<All>, NetGraphMsgHandler<Arc<chaininterface::ChainWatchInterfaceUtil>, Arc<test_utils::TestLogger>>) {
+       fn create_net_graph_msg_handler() -> (Secp256k1<All>, NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>) {
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(test_utils::TestLogger::new());
-               let chain_monitor = Arc::new(chaininterface::ChainWatchInterfaceUtil::new(Network::Testnet));
-               let net_graph_msg_handler = NetGraphMsgHandler::new(chain_monitor, Arc::clone(&logger));
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_hash, None, Arc::clone(&logger));
                (secp_ctx, net_graph_msg_handler)
        }
 
@@ -862,7 +1149,7 @@ mod tests {
                        // Announce a channel to add a corresponding node.
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::known(),
-                               chain_hash: genesis_block(Network::Testnet).header.bitcoin_hash(),
+                               chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                                short_channel_id: 0,
                                node_id_1,
                                node_id_2,
@@ -901,7 +1188,7 @@ mod tests {
                };
 
                unsigned_announcement.timestamp += 1000;
-               unsigned_announcement.excess_data.push(1);
+               unsigned_announcement.excess_data.resize(MAX_EXCESS_BYTES_FOR_RELAY + 1, 0);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let announcement_with_data = NodeAnnouncement {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
@@ -932,9 +1219,6 @@ mod tests {
        fn handling_channel_announcements() {
                let secp_ctx = Secp256k1::new();
                let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());
-               let chain_monitor = Arc::new(test_utils::TestChainWatcher::new());
-               let net_graph_msg_handler = NetGraphMsgHandler::new(chain_monitor.clone(), Arc::clone(&logger));
-
 
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
@@ -952,7 +1236,7 @@ mod tests {
 
                let mut unsigned_announcement = UnsignedChannelAnnouncement {
                        features: ChannelFeatures::known(),
-                       chain_hash: genesis_block(Network::Testnet).header.bitcoin_hash(),
+                       chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 0,
                        node_id_1,
                        node_id_2,
@@ -971,8 +1255,7 @@ mod tests {
                };
 
                // Test if the UTXO lookups were not supported
-               *chain_monitor.utxo_ret.lock().unwrap() = Err(chaininterface::ChainError::NotSupported);
-
+               let mut net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger));
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
@@ -986,7 +1269,6 @@ mod tests {
                        }
                }
 
-
                // If we receive announcement for the same channel (with UTXO lookups disabled),
                // drop new one on the floor, since we can't see any changes.
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
@@ -994,9 +1276,10 @@ mod tests {
                        Err(e) => assert_eq!(e.err, "Already have knowledge of channel")
                };
 
-
                // Test if an associated transaction were not on-chain (or not confirmed).
-               *chain_monitor.utxo_ret.lock().unwrap() = Err(chaininterface::ChainError::UnknownTx);
+               let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+               *chain_source.utxo_ret.lock().unwrap() = Err(chain::AccessError::UnknownTx);
+               net_graph_msg_handler = NetGraphMsgHandler::new(chain_source.clone().genesis_hash, Some(chain_source.clone()), Arc::clone(&logger));
                unsigned_announcement.short_channel_id += 1;
 
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
@@ -1013,10 +1296,9 @@ mod tests {
                        Err(e) => assert_eq!(e.err, "Channel announced without corresponding UTXO entry")
                };
 
-
                // Now test if the transaction is found in the UTXO set and the script is correct.
                unsigned_announcement.short_channel_id += 1;
-               *chain_monitor.utxo_ret.lock().unwrap() = Ok((good_script.clone(), 0));
+               *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script.clone() });
 
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
@@ -1041,14 +1323,14 @@ mod tests {
 
                // If we receive announcement for the same channel (but TX is not confirmed),
                // drop new one on the floor, since we can't see any changes.
-               *chain_monitor.utxo_ret.lock().unwrap() = Err(chaininterface::ChainError::UnknownTx);
+               *chain_source.utxo_ret.lock().unwrap() = Err(chain::AccessError::UnknownTx);
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(_) => panic!(),
                        Err(e) => assert_eq!(e.err, "Channel announced without corresponding UTXO entry")
                };
 
                // But if it is confirmed, replace the channel
-               *chain_monitor.utxo_ret.lock().unwrap() = Ok((good_script, 0));
+               *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: 0, script_pubkey: good_script });
                unsigned_announcement.features = ChannelFeatures::empty();
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
@@ -1074,7 +1356,7 @@ mod tests {
 
                // Don't relay valid channels with excess data
                unsigned_announcement.short_channel_id += 1;
-               unsigned_announcement.excess_data.push(1);
+               unsigned_announcement.excess_data.resize(MAX_EXCESS_BYTES_FOR_RELAY + 1, 0);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let valid_announcement = ChannelAnnouncement {
                        node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
@@ -1104,8 +1386,8 @@ mod tests {
                unsigned_announcement.node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                let channel_to_itself_announcement = ChannelAnnouncement {
-                       node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
-                       node_signature_2: secp_ctx.sign(&msghash, node_1_privkey),
+                       node_signature_1: secp_ctx.sign(&msghash, node_2_privkey),
+                       node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
                        bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
                        bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                        contents: unsigned_announcement.clone(),
@@ -1118,7 +1400,11 @@ mod tests {
 
        #[test]
        fn handling_channel_update() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let secp_ctx = Secp256k1::new();
+               let logger: Arc<Logger> = Arc::new(test_utils::TestLogger::new());
+               let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+               let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), Some(chain_source.clone()), Arc::clone(&logger));
+
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
@@ -1128,9 +1414,17 @@ mod tests {
 
                let zero_hash = Sha256dHash::hash(&[0; 32]);
                let short_channel_id = 0;
-               let chain_hash = genesis_block(Network::Testnet).header.bitcoin_hash();
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+               let amount_sats = 1000_000;
+
                {
                        // Announce a channel we will update
+                       let good_script = Builder::new().push_opcode(opcodes::all::OP_PUSHNUM_2)
+                          .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_1_btckey).serialize())
+                          .push_slice(&PublicKey::from_secret_key(&secp_ctx, node_2_btckey).serialize())
+                          .push_opcode(opcodes::all::OP_PUSHNUM_2)
+                          .push_opcode(opcodes::all::OP_CHECKMULTISIG).into_script().to_v0_p2wsh();
+                       *chain_source.utxo_ret.lock().unwrap() = Ok(TxOut { value: amount_sats, script_pubkey: good_script.clone() });
                        let unsigned_announcement = UnsignedChannelAnnouncement {
                                features: ChannelFeatures::empty(),
                                chain_hash,
@@ -1192,7 +1486,7 @@ mod tests {
                }
 
                unsigned_channel_update.timestamp += 100;
-               unsigned_channel_update.excess_data.push(1);
+               unsigned_channel_update.excess_data.resize(MAX_EXCESS_BYTES_FOR_RELAY + 1, 0);
                let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                let valid_channel_update = ChannelUpdate {
                        signature: secp_ctx.sign(&msghash, node_1_privkey),
@@ -1218,6 +1512,31 @@ mod tests {
                };
                unsigned_channel_update.short_channel_id = short_channel_id;
 
+               unsigned_channel_update.htlc_maximum_msat = OptionalField::Present(MAX_VALUE_MSAT + 1);
+               let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
+               let valid_channel_update = ChannelUpdate {
+                       signature: secp_ctx.sign(&msghash, node_1_privkey),
+                       contents: unsigned_channel_update.clone()
+               };
+
+               match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
+                       Ok(_) => panic!(),
+                       Err(e) => assert_eq!(e.err, "htlc_maximum_msat is larger than maximum possible msats")
+               };
+               unsigned_channel_update.htlc_maximum_msat = OptionalField::Absent;
+
+               unsigned_channel_update.htlc_maximum_msat = OptionalField::Present(amount_sats * 1000 + 1);
+               let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
+               let valid_channel_update = ChannelUpdate {
+                       signature: secp_ctx.sign(&msghash, node_1_privkey),
+                       contents: unsigned_channel_update.clone()
+               };
+
+               match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
+                       Ok(_) => panic!(),
+                       Err(e) => assert_eq!(e.err, "htlc_maximum_msat is larger than channel capacity or capacity is bogus")
+               };
+               unsigned_channel_update.htlc_maximum_msat = OptionalField::Absent;
 
                // Even though previous update was not relayed further, we still accepted it,
                // so we now won't accept update before the previous one.
@@ -1258,7 +1577,7 @@ mod tests {
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
 
                let short_channel_id = 0;
-               let chain_hash = genesis_block(Network::Testnet).header.bitcoin_hash();
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
 
                {
                        // There is no nodes in the table at the beginning.
@@ -1373,7 +1692,7 @@ mod tests {
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
 
                let short_channel_id = 1;
-               let chain_hash = genesis_block(Network::Testnet).header.bitcoin_hash();
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
 
                // Channels were not announced yet.
                let channels_with_announcements = net_graph_msg_handler.get_next_channel_announcements(0, 1);
@@ -1467,7 +1786,7 @@ mod tests {
                                htlc_maximum_msat: OptionalField::Absent,
                                fee_base_msat: 10000,
                                fee_proportional_millionths: 20,
-                               excess_data: [1; 3].to_vec()
+                               excess_data: [1; MAX_EXCESS_BYTES_FOR_RELAY + 1].to_vec()
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_channel_update.encode()[..])[..]);
                        let valid_channel_update = ChannelUpdate {
@@ -1507,7 +1826,7 @@ mod tests {
                let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
 
                let short_channel_id = 1;
-               let chain_hash = genesis_block(Network::Testnet).header.bitcoin_hash();
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
 
                // No nodes yet.
                let next_announcements = net_graph_msg_handler.get_next_node_announcements(None, 10);
@@ -1596,7 +1915,7 @@ mod tests {
                                alias: [0; 32],
                                addresses: Vec::new(),
                                excess_address_data: Vec::new(),
-                               excess_data: [1; 3].to_vec(),
+                               excess_data: [1; MAX_EXCESS_BYTES_FOR_RELAY + 1].to_vec(),
                        };
                        let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
                        let valid_announcement = NodeAnnouncement {
@@ -1627,7 +1946,7 @@ mod tests {
                let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
                let unsigned_announcement = UnsignedChannelAnnouncement {
                        features: ChannelFeatures::known(),
-                       chain_hash: genesis_block(Network::Testnet).header.bitcoin_hash(),
+                       chain_hash: genesis_block(Network::Testnet).header.block_hash(),
                        short_channel_id: 0,
                        node_id_1,
                        node_id_2,
@@ -1679,4 +1998,490 @@ mod tests {
                network.write(&mut w).unwrap();
                assert!(<NetworkGraph>::read(&mut ::std::io::Cursor::new(&w.0)).unwrap() == *network);
        }
+
+       #[test]
+       fn calling_sync_routing_table() {
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
+               let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);
+
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+               let first_blocknum = 0;
+               let number_of_blocks = 0xffff_ffff;
+
+               // It should ignore if gossip_queries feature is not enabled
+               {
+                       let init_msg = Init { features: InitFeatures::known().clear_gossip_queries() };
+                       net_graph_msg_handler.sync_routing_table(&node_id_1, &init_msg);
+                       let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
+                       assert_eq!(events.len(), 0);
+               }
+
+               // It should send a query_channel_message with the correct information
+               {
+                       let init_msg = Init { features: InitFeatures::known() };
+                       net_graph_msg_handler.sync_routing_table(&node_id_1, &init_msg);
+                       let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
+                       assert_eq!(events.len(), 1);
+                       match &events[0] {
+                               MessageSendEvent::SendChannelRangeQuery{ node_id, msg } => {
+                                       assert_eq!(node_id, &node_id_1);
+                                       assert_eq!(msg.chain_hash, chain_hash);
+                                       assert_eq!(msg.first_blocknum, first_blocknum);
+                                       assert_eq!(msg.number_of_blocks, number_of_blocks);
+                               },
+                               _ => panic!("Expected MessageSendEvent::SendChannelRangeQuery")
+                       };
+               }
+
+               // It should not enqueue a query when should_request_full_sync return false.
+               // The initial implementation allows syncing with the first 5 peers after
+               // which should_request_full_sync will return false
+               {
+                       let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+                       let init_msg = Init { features: InitFeatures::known() };
+                       for n in 1..7 {
+                               let node_privkey = &SecretKey::from_slice(&[n; 32]).unwrap();
+                               let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
+                               net_graph_msg_handler.sync_routing_table(&node_id, &init_msg);
+                               let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
+                               if n <= 5 {
+                                       assert_eq!(events.len(), 1);
+                               } else {
+                                       assert_eq!(events.len(), 0);
+                               }
+
+                       }
+               }
+       }
+
+       #[test]
+       fn handling_reply_channel_range() {
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
+               let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);
+
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+
+               // Test receipt of a single reply that should enqueue an SCID query
+               // matching the SCIDs in the reply
+               {
+                       let result = net_graph_msg_handler.handle_reply_channel_range(&node_id_1, ReplyChannelRange {
+                               chain_hash,
+                               sync_complete: true,
+                               first_blocknum: 0,
+                               number_of_blocks: 2000,
+                               short_channel_ids: vec![
+                                       0x0003e0_000000_0000, // 992x0x0
+                                       0x0003e8_000000_0000, // 1000x0x0
+                                       0x0003e9_000000_0000, // 1001x0x0
+                                       0x0003f0_000000_0000, // 1008x0x0
+                                       0x00044c_000000_0000, // 1100x0x0
+                                       0x0006e0_000000_0000, // 1760x0x0
+                               ],
+                       });
+                       assert!(result.is_ok());
+
+                       // We expect to emit a query_short_channel_ids message with the received scids
+                       let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
+                       assert_eq!(events.len(), 1);
+                       match &events[0] {
+                               MessageSendEvent::SendShortIdsQuery { node_id, msg } => {
+                                       assert_eq!(node_id, &node_id_1);
+                                       assert_eq!(msg.chain_hash, chain_hash);
+                                       assert_eq!(msg.short_channel_ids, vec![
+                                               0x0003e0_000000_0000, // 992x0x0
+                                               0x0003e8_000000_0000, // 1000x0x0
+                                               0x0003e9_000000_0000, // 1001x0x0
+                                               0x0003f0_000000_0000, // 1008x0x0
+                                               0x00044c_000000_0000, // 1100x0x0
+                                               0x0006e0_000000_0000, // 1760x0x0
+                                       ]);
+                               },
+                               _ => panic!("expected MessageSendEvent::SendShortIdsQuery"),
+                       }
+               }
+       }
+
+       #[test]
+       fn handling_reply_short_channel_ids() {
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
+               let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
+
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+
+               // Test receipt of a successful reply
+               {
+                       let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, ReplyShortChannelIdsEnd {
+                               chain_hash,
+                               full_information: true,
+                       });
+                       assert!(result.is_ok());
+               }
+
+               // Test receipt of a reply that indicates the peer does not maintain up-to-date information
+               // for the chain_hash requested in the query.
+               {
+                       let result = net_graph_msg_handler.handle_reply_short_channel_ids_end(&node_id, ReplyShortChannelIdsEnd {
+                               chain_hash,
+                               full_information: false,
+                       });
+                       assert!(result.is_err());
+                       assert_eq!(result.err().unwrap().err, "Received reply_short_channel_ids_end with no information");
+               }
+       }
+
+       #[test]
+       fn handling_query_channel_range() {
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+               let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
+               let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
+               let node_1_btckey = &SecretKey::from_slice(&[40; 32]).unwrap();
+               let node_2_btckey = &SecretKey::from_slice(&[39; 32]).unwrap();
+               let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_1_privkey);
+               let node_id_2 = PublicKey::from_secret_key(&secp_ctx, node_2_privkey);
+               let bitcoin_key_1 = PublicKey::from_secret_key(&secp_ctx, node_1_btckey);
+               let bitcoin_key_2 = PublicKey::from_secret_key(&secp_ctx, node_2_btckey);
+
+               let mut scids: Vec<u64> = vec![
+                       scid_from_parts(0xfffffe, 0xffffff, 0xffff).unwrap(), // max
+                       scid_from_parts(0xffffff, 0xffffff, 0xffff).unwrap(), // never
+               ];
+
+               // used for testing multipart reply across blocks
+               for block in 100000..=108001 {
+                       scids.push(scid_from_parts(block, 0, 0).unwrap());
+               }
+
+               // used for testing resumption on same block
+               scids.push(scid_from_parts(108001, 1, 0).unwrap());
+
+               for scid in scids {
+                       let unsigned_announcement = UnsignedChannelAnnouncement {
+                               features: ChannelFeatures::known(),
+                               chain_hash: chain_hash.clone(),
+                               short_channel_id: scid,
+                               node_id_1,
+                               node_id_2,
+                               bitcoin_key_1,
+                               bitcoin_key_2,
+                               excess_data: Vec::new(),
+                       };
+
+                       let msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
+                       let valid_announcement = ChannelAnnouncement {
+                               node_signature_1: secp_ctx.sign(&msghash, node_1_privkey),
+                               node_signature_2: secp_ctx.sign(&msghash, node_2_privkey),
+                               bitcoin_signature_1: secp_ctx.sign(&msghash, node_1_btckey),
+                               bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
+                               contents: unsigned_announcement.clone(),
+                       };
+                       match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
+                               Ok(_) => (),
+                               _ => panic!()
+                       };
+               }
+
+               // Error when number_of_blocks=0
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0,
+                               number_of_blocks: 0,
+                       },
+                       false,
+                       vec![ReplyChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0,
+                               number_of_blocks: 0,
+                               sync_complete: true,
+                               short_channel_ids: vec![]
+                       }]
+               );
+
+               // Error when wrong chain
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: genesis_block(Network::Bitcoin).header.block_hash(),
+                               first_blocknum: 0,
+                               number_of_blocks: 0xffff_ffff,
+                       },
+                       false,
+                       vec![ReplyChannelRange {
+                               chain_hash: genesis_block(Network::Bitcoin).header.block_hash(),
+                               first_blocknum: 0,
+                               number_of_blocks: 0xffff_ffff,
+                               sync_complete: true,
+                               short_channel_ids: vec![],
+                       }]
+               );
+
+               // Error when first_blocknum > 0xffffff
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0x01000000,
+                               number_of_blocks: 0xffff_ffff,
+                       },
+                       false,
+                       vec![ReplyChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0x01000000,
+                               number_of_blocks: 0xffff_ffff,
+                               sync_complete: true,
+                               short_channel_ids: vec![]
+                       }]
+               );
+
+               // Empty reply when max valid SCID block num
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0xffffff,
+                               number_of_blocks: 1,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 0xffffff,
+                                       number_of_blocks: 1,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![]
+                               },
+                       ]
+               );
+
+               // No results in valid query range
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 1000,
+                               number_of_blocks: 1000,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 1000,
+                                       number_of_blocks: 1000,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![],
+                               }
+                       ]
+               );
+
+               // Overflow first_blocknum + number_of_blocks
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 0xfe0000,
+                               number_of_blocks: 0xffffffff,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 0xfe0000,
+                                       number_of_blocks: 0xffffffff - 0xfe0000,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![
+                                               0xfffffe_ffffff_ffff, // max
+                                       ]
+                               }
+                       ]
+               );
+
+               // Single block exactly full
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 100000,
+                               number_of_blocks: 8000,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 100000,
+                                       number_of_blocks: 8000,
+                                       sync_complete: true,
+                                       short_channel_ids: (100000..=107999)
+                                               .map(|block| scid_from_parts(block, 0, 0).unwrap())
+                                               .collect(),
+                               },
+                       ]
+               );
+
+               // Multiple split on new block
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 100000,
+                               number_of_blocks: 8001,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 100000,
+                                       number_of_blocks: 7999,
+                                       sync_complete: false,
+                                       short_channel_ids: (100000..=107999)
+                                               .map(|block| scid_from_parts(block, 0, 0).unwrap())
+                                               .collect(),
+                               },
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 107999,
+                                       number_of_blocks: 2,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![
+                                               scid_from_parts(108000, 0, 0).unwrap(),
+                                       ],
+                               }
+                       ]
+               );
+
+               // Multiple split on same block
+               do_handling_query_channel_range(
+                       &net_graph_msg_handler,
+                       &node_id_2,
+                       QueryChannelRange {
+                               chain_hash: chain_hash.clone(),
+                               first_blocknum: 100002,
+                               number_of_blocks: 8000,
+                       },
+                       true,
+                       vec![
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 100002,
+                                       number_of_blocks: 7999,
+                                       sync_complete: false,
+                                       short_channel_ids: (100002..=108001)
+                                               .map(|block| scid_from_parts(block, 0, 0).unwrap())
+                                               .collect(),
+                               },
+                               ReplyChannelRange {
+                                       chain_hash: chain_hash.clone(),
+                                       first_blocknum: 108001,
+                                       number_of_blocks: 1,
+                                       sync_complete: true,
+                                       short_channel_ids: vec![
+                                               scid_from_parts(108001, 1, 0).unwrap(),
+                                       ],
+                               }
+                       ]
+               );
+       }
+
+       fn do_handling_query_channel_range(
+               net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+               test_node_id: &PublicKey,
+               msg: QueryChannelRange,
+               expected_ok: bool,
+               expected_replies: Vec<ReplyChannelRange>
+       ) {
+               let mut max_firstblocknum = msg.first_blocknum.saturating_sub(1);
+               let mut c_lightning_0_9_prev_end_blocknum = max_firstblocknum;
+               let query_end_blocknum = msg.end_blocknum();
+               let result = net_graph_msg_handler.handle_query_channel_range(test_node_id, msg);
+
+               if expected_ok {
+                       assert!(result.is_ok());
+               } else {
+                       assert!(result.is_err());
+               }
+
+               let events = net_graph_msg_handler.get_and_clear_pending_msg_events();
+               assert_eq!(events.len(), expected_replies.len());
+
+               for i in 0..events.len() {
+                       let expected_reply = &expected_replies[i];
+                       match &events[i] {
+                               MessageSendEvent::SendReplyChannelRange { node_id, msg } => {
+                                       assert_eq!(node_id, test_node_id);
+                                       assert_eq!(msg.chain_hash, expected_reply.chain_hash);
+                                       assert_eq!(msg.first_blocknum, expected_reply.first_blocknum);
+                                       assert_eq!(msg.number_of_blocks, expected_reply.number_of_blocks);
+                                       assert_eq!(msg.sync_complete, expected_reply.sync_complete);
+                                       assert_eq!(msg.short_channel_ids, expected_reply.short_channel_ids);
+
+                                       // Enforce exactly the sequencing requirements present on c-lightning v0.9.3
+                                       assert!(msg.first_blocknum == c_lightning_0_9_prev_end_blocknum || msg.first_blocknum == c_lightning_0_9_prev_end_blocknum.saturating_add(1));
+                                       assert!(msg.first_blocknum >= max_firstblocknum);
+                                       max_firstblocknum = msg.first_blocknum;
+                                       c_lightning_0_9_prev_end_blocknum = msg.first_blocknum.saturating_add(msg.number_of_blocks);
+
+                                       // Check that the last block count is >= the query's end_blocknum
+                                       if i == events.len() - 1 {
+                                               assert!(msg.first_blocknum.saturating_add(msg.number_of_blocks) >= query_end_blocknum);
+                                       }
+                               },
+                               _ => panic!("expected MessageSendEvent::SendReplyChannelRange"),
+                       }
+               }
+       }
+
+       #[test]
+       fn handling_query_short_channel_ids() {
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
+               let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
+
+               let chain_hash = genesis_block(Network::Testnet).header.block_hash();
+
+               let result = net_graph_msg_handler.handle_query_short_channel_ids(&node_id, QueryShortChannelIds {
+                       chain_hash,
+                       short_channel_ids: vec![0x0003e8_000000_0000],
+               });
+               assert!(result.is_err());
+       }
+}
+
+#[cfg(all(test, feature = "unstable"))]
+mod benches {
+       use super::*;
+
+       use test::Bencher;
+       use std::io::Read;
+
+       #[bench]
+       fn read_network_graph(bench: &mut Bencher) {
+               let mut d = ::routing::router::test_utils::get_route_file().unwrap();
+               let mut v = Vec::new();
+               d.read_to_end(&mut v).unwrap();
+               bench.iter(|| {
+                       let _ = NetworkGraph::read(&mut std::io::Cursor::new(&v)).unwrap();
+               });
+       }
+
+       #[bench]
+       fn write_network_graph(bench: &mut Bencher) {
+               let mut d = ::routing::router::test_utils::get_route_file().unwrap();
+               let net_graph = NetworkGraph::read(&mut d).unwrap();
+               bench.iter(|| {
+                       let _ = net_graph.encode();
+               });
+       }
 }