Add a comment describing the timestamp field's use
[rust-lightning] / lightning / src / routing / network_graph.rs
index 7f0866030c2ff1a4de3c37866235fbdb92b0fe66..10c0ba57b58b05e2a6875795773e4a19188c6cb1 100644 (file)
@@ -9,6 +9,7 @@
 
 //! The top-level network map tracking logic lives here.
 
+use bitcoin::secp256k1::constants::PUBLIC_KEY_SIZE;
 use bitcoin::secp256k1::key::PublicKey;
 use bitcoin::secp256k1::Secp256k1;
 use bitcoin::secp256k1;
@@ -28,16 +29,17 @@ use ln::msgs::{ChannelAnnouncement, ChannelUpdate, NodeAnnouncement, OptionalFie
 use ln::msgs::{QueryChannelRange, ReplyChannelRange, QueryShortChannelIds, ReplyShortChannelIdsEnd};
 use ln::msgs;
 use util::ser::{Writeable, Readable, Writer};
-use util::logger::Logger;
-use util::events::{MessageSendEvent, MessageSendEventsProvider};
+use util::logger::{Logger, Level};
+use util::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
 use util::scid_utils::{block_from_scid, scid_from_parts, MAX_SCID_BLOCK};
 
+use io;
 use prelude::*;
 use alloc::collections::{BTreeMap, btree_map::Entry as BtreeEntry};
 use core::{cmp, fmt};
-use std::sync::{RwLock, RwLockReadGuard};
+use sync::{RwLock, RwLockReadGuard};
 use core::sync::atomic::{AtomicUsize, Ordering};
-use std::sync::Mutex;
+use sync::Mutex;
 use core::ops::Deref;
 use bitcoin::hashes::hex::ToHex;
 
@@ -49,57 +51,183 @@ const MAX_EXCESS_BYTES_FOR_RELAY: usize = 1024;
 /// 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 compressed public key of a node
+#[derive(Clone, Copy)]
+pub struct NodeId([u8; PUBLIC_KEY_SIZE]);
+
+impl NodeId {
+       /// Create a new NodeId from a public key
+       pub fn from_pubkey(pubkey: &PublicKey) -> Self {
+               NodeId(pubkey.serialize())
+       }
+       
+       /// Get the public key slice from this NodeId
+       pub fn as_slice(&self) -> &[u8] {
+               &self.0
+       }
+}
+
+impl fmt::Debug for NodeId {
+       fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+               write!(f, "NodeId({})", log_bytes!(self.0))
+       }
+}
+
+impl core::hash::Hash for NodeId {
+       fn hash<H: core::hash::Hasher>(&self, hasher: &mut H) {
+               self.0.hash(hasher);
+       }
+}
+
+impl Eq for NodeId {}
+
+impl PartialEq for NodeId {
+       fn eq(&self, other: &Self) -> bool {
+               self.0[..] == other.0[..]
+       }
+}
+
+impl cmp::PartialOrd for NodeId {
+       fn partial_cmp(&self, other: &Self) -> Option<cmp::Ordering> {
+               Some(self.cmp(other))
+       }
+}
+
+impl Ord for NodeId {
+       fn cmp(&self, other: &Self) -> cmp::Ordering {
+               self.0[..].cmp(&other.0[..])
+       }
+}
+
+impl Writeable for NodeId {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), io::Error> {
+               writer.write_all(&self.0)?;
+               Ok(())
+       }
+}
+
+impl Readable for NodeId {
+       fn read<R: io::Read>(reader: &mut R) -> Result<Self, DecodeError> {
+               let mut buf = [0; PUBLIC_KEY_SIZE];
+               reader.read_exact(&mut buf)?;
+               Ok(Self(buf))
+       }
+}
+
 /// 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>,
+       // Lock order: channels -> nodes
+       channels: RwLock<BTreeMap<u64, ChannelInfo>>,
+       nodes: RwLock<BTreeMap<NodeId, 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>);
+impl Clone for NetworkGraph {
+       fn clone(&self) -> Self {
+               let channels = self.channels.read().unwrap();
+               let nodes = self.nodes.read().unwrap();
+               Self {
+                       genesis_hash: self.genesis_hash.clone(),
+                       channels: RwLock::new(channels.clone()),
+                       nodes: RwLock::new(nodes.clone()),
+               }
+       }
+}
+
+/// A read-only view of [`NetworkGraph`].
+pub struct ReadOnlyNetworkGraph<'a> {
+       channels: RwLockReadGuard<'a, BTreeMap<u64, ChannelInfo>>,
+       nodes: RwLockReadGuard<'a, BTreeMap<NodeId, NodeInfo>>,
+}
+
+/// Update to the [`NetworkGraph`] based on payment failure information conveyed via the Onion
+/// return packet by a node along the route. See [BOLT #4] for details.
+///
+/// [BOLT #4]: https://github.com/lightningnetwork/lightning-rfc/blob/master/04-onion-routing.md
+#[derive(Clone, Debug, PartialEq)]
+pub enum NetworkUpdate {
+       /// An error indicating a `channel_update` messages should be applied via
+       /// [`NetworkGraph::update_channel`].
+       ChannelUpdateMessage {
+               /// The update to apply via [`NetworkGraph::update_channel`].
+               msg: ChannelUpdate,
+       },
+       /// An error indicating only that a channel has been closed, which should be applied via
+       /// [`NetworkGraph::close_channel_from_update`].
+       ChannelClosed {
+               /// The short channel id of the closed channel.
+               short_channel_id: u64,
+               /// Whether the channel should be permanently removed or temporarily disabled until a new
+               /// `channel_update` message is received.
+               is_permanent: bool,
+       },
+       /// An error indicating only that a node has failed, which should be applied via
+       /// [`NetworkGraph::fail_node`].
+       NodeFailure {
+               /// The node id of the failed node.
+               node_id: PublicKey,
+               /// Whether the node should be permanently removed from consideration or can be restored
+               /// when a new `channel_update` message is received.
+               is_permanent: bool,
+       }
+}
+
+impl_writeable_tlv_based_enum_upgradable!(NetworkUpdate,
+       (0, ChannelUpdateMessage) => {
+               (0, msg, required),
+       },
+       (2, ChannelClosed) => {
+               (0, short_channel_id, required),
+               (2, is_permanent, required),
+       },
+       (4, NodeFailure) => {
+               (0, node_id, required),
+               (2, is_permanent, required),
+       },
+);
+
+impl<G: Deref<Target=NetworkGraph>, C: Deref, L: Deref> EventHandler for NetGraphMsgHandler<G, C, L>
+where C::Target: chain::Access, L::Target: Logger {
+       fn handle_event(&self, event: &Event) {
+               if let Event::PaymentPathFailed { payment_hash: _, rejected_by_dest: _, network_update, .. } = event {
+                       if let Some(network_update) = network_update {
+                               self.handle_network_update(network_update);
+                       }
+               }
+       }
+}
 
 /// 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: chain::Access, L::Target: Logger {
+///
+/// Serves as an [`EventHandler`] for applying updates from [`Event::PaymentPathFailed`] to the
+/// [`NetworkGraph`].
+pub struct NetGraphMsgHandler<G: Deref<Target=NetworkGraph>, 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>,
+       network_graph: G,
        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: chain::Access, L::Target: Logger {
+impl<G: Deref<Target=NetworkGraph>, C: Deref, L: Deref> NetGraphMsgHandler<G, 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.
+       /// assuming an existing 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(genesis_hash: BlockHash, chain_access: Option<C>, logger: L) -> Self {
+       pub fn new(network_graph: G, chain_access: Option<C>, logger: L) -> Self {
                NetGraphMsgHandler {
                        secp_ctx: Secp256k1::verification_only(),
-                       network_graph: RwLock::new(NetworkGraph::new(genesis_hash)),
-                       full_syncs_requested: AtomicUsize::new(0),
-                       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_access: Option<C>, logger: L, network_graph: NetworkGraph) -> Self {
-               NetGraphMsgHandler {
-                       secp_ctx: Secp256k1::verification_only(),
-                       network_graph: RwLock::new(network_graph),
+                       network_graph,
                        full_syncs_requested: AtomicUsize::new(0),
                        chain_access,
                        pending_events: Mutex::new(vec![]),
@@ -114,14 +242,6 @@ impl<C: Deref, L: Deref> NetGraphMsgHandler<C, L> where C::Target: chain::Access
                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.
@@ -133,16 +253,31 @@ impl<C: Deref, L: Deref> NetGraphMsgHandler<C, L> where C::Target: chain::Access
                        false
                }
        }
-}
 
-impl<'a> LockedNetworkGraph<'a> {
-       /// Get a reference to the NetworkGraph which this read-lock contains.
-       pub fn graph(&self) -> &NetworkGraph {
-               &*self.0
+       /// Applies changes to the [`NetworkGraph`] from the given update.
+       fn handle_network_update(&self, update: &NetworkUpdate) {
+               match *update {
+                       NetworkUpdate::ChannelUpdateMessage { ref msg } => {
+                               let short_channel_id = msg.contents.short_channel_id;
+                               let is_enabled = msg.contents.flags & (1 << 1) != (1 << 1);
+                               let status = if is_enabled { "enabled" } else { "disabled" };
+                               log_debug!(self.logger, "Updating channel with channel_update from a payment failure. Channel {} is {}.", short_channel_id, status);
+                               let _ = self.network_graph.update_channel(msg, &self.secp_ctx);
+                       },
+                       NetworkUpdate::ChannelClosed { short_channel_id, is_permanent } => {
+                               let action = if is_permanent { "Removing" } else { "Disabling" };
+                               log_debug!(self.logger, "{} channel graph entry for {} due to a payment failure.", action, short_channel_id);
+                               self.network_graph.close_channel_from_update(short_channel_id, is_permanent);
+                       },
+                       NetworkUpdate::NodeFailure { ref node_id, is_permanent } => {
+                               let action = if is_permanent { "Removing" } else { "Disabling" };
+                               log_debug!(self.logger, "{} node graph entry for {} due to a payment failure.", action, node_id);
+                               self.network_graph.fail_node(node_id, is_permanent);
+                       },
+               }
        }
 }
 
-
 macro_rules! secp_verify_sig {
        ( $secp_ctx: expr, $msg: expr, $sig: expr, $pubkey: expr ) => {
                match $secp_ctx.verify($msg, $sig, $pubkey) {
@@ -152,43 +287,31 @@ macro_rules! secp_verify_sig {
        };
 }
 
-impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> where C::Target: chain::Access, L::Target: Logger {
+impl<G: Deref<Target=NetworkGraph>, C: Deref, L: Deref> RoutingMessageHandler for NetGraphMsgHandler<G, 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, &self.secp_ctx)?;
+               self.network_graph.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> {
-               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 { "" });
+               self.network_graph.update_channel_from_announcement(msg, &self.chain_access, &self.secp_ctx)?;
+               log_gossip!(self.logger, "Added channel_announcement for {}{}", msg.contents.short_channel_id, if !msg.contents.excess_data.is_empty() { " with excess uninterpreted data!" } else { "" });
                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, &self.secp_ctx);
-                       },
-                       &msgs::HTLCFailChannelUpdate::ChannelClosed { short_channel_id, is_permanent } => {
-                               self.network_graph.write().unwrap().close_channel_from_update(short_channel_id, is_permanent);
-                       },
-                       &msgs::HTLCFailChannelUpdate::NodeFailure { ref node_id, is_permanent } => {
-                               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, &self.secp_ctx)?;
+               self.network_graph.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<(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..);
+               let channels = self.network_graph.channels.read().unwrap();
+               let mut iter = channels.range(starting_point..);
                while result.len() < batch_amount as usize {
                        if let Some((_, ref chan)) = iter.next() {
                                if chan.announcement_message.is_some() {
@@ -214,14 +337,14 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
        }
 
        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 nodes = self.network_graph.nodes.read().unwrap();
                let mut iter = if let Some(pubkey) = starting_point {
-                               let mut iter = network_graph.get_nodes().range((*pubkey)..);
+                               let mut iter = nodes.range(NodeId::from_pubkey(pubkey)..);
                                iter.next();
                                iter
                        } else {
-                               network_graph.get_nodes().range(..)
+                               nodes.range::<NodeId, _>(..)
                        };
                while result.len() < batch_amount as usize {
                        if let Some((_, ref node)) = iter.next() {
@@ -254,7 +377,7 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
                }
 
                // Check if we need to perform a full synchronization with this peer
-               if !self.should_request_full_sync(their_node_id) {
+               if !self.should_request_full_sync(&their_node_id) {
                        return ();
                }
 
@@ -265,7 +388,7 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
                pending_events.push(MessageSendEvent::SendChannelRangeQuery {
                        node_id: their_node_id.clone(),
                        msg: QueryChannelRange {
-                               chain_hash: self.network_graph.read().unwrap().genesis_hash,
+                               chain_hash: self.network_graph.genesis_hash,
                                first_blocknum,
                                number_of_blocks,
                        },
@@ -327,8 +450,6 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
        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.
@@ -336,7 +457,7 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
                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 {
+               if msg.chain_hash != self.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(),
@@ -358,7 +479,8 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
                // (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()) {
+               let channels = self.network_graph.channels.read().unwrap();
+               for (_, ref chan) in 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() {
@@ -369,27 +491,43 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
                                batch.push(chan_announcement.contents.short_channel_id);
                        }
                }
-               drop(network_graph);
+               drop(channels);
 
                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
-                       // must be >= the prior reply. We'll simplify this by using zero since its still spec compliant and
-                       // sequence completion is now explicitly.
-                       let first_blocknum = 0;
-
-                       // Per spec, the final end_blocknum needs to be >= the query's end_blocknum, so we'll use the
-                       // query's value. Prior batches must use the number of blocks that fit into the message. We'll
-                       // base this off the last SCID in the batch since we've somewhat abusing first_blocknum.
-                       let number_of_blocks = if batch_index == batch_count-1 {
-                               msg.end_blocknum()
-                       } else {
-                               block_from_scid(batch.last().unwrap()) + 1
+                       // 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)
                        };
 
-                       // Only true for the last message in a sequence
-                       let sync_complete = batch_index == batch_count - 1;
+                       prev_batch_endblock = first_blocknum + number_of_blocks;
 
                        pending_events.push(MessageSendEvent::SendReplyChannelRange {
                                node_id: their_node_id.clone(),
@@ -415,7 +553,7 @@ impl<C: Deref , L: Deref > RoutingMessageHandler for NetGraphMsgHandler<C, L> wh
        }
 }
 
-impl<C: Deref, L: Deref> MessageSendEventsProvider for NetGraphMsgHandler<C, L>
+impl<G: Deref<Target=NetworkGraph>, C: Deref, L: Deref> MessageSendEventsProvider for NetGraphMsgHandler<G, C, L>
 where
        C::Target: chain::Access,
        L::Target: Logger,
@@ -476,11 +614,11 @@ pub struct ChannelInfo {
        /// Protocol features of a channel communicated during its announcement
        pub features: ChannelFeatures,
        /// Source node of the first direction of a channel
-       pub node_one: PublicKey,
+       pub node_one: NodeId,
        /// Details about the first direction of a channel
        pub one_to_two: Option<DirectionalChannelInfo>,
        /// Source node of the second direction of a channel
-       pub node_two: PublicKey,
+       pub node_two: NodeId,
        /// Details about the second direction of a channel
        pub two_to_one: Option<DirectionalChannelInfo>,
        /// The channel capacity as seen on-chain, if chain lookup is available.
@@ -495,7 +633,7 @@ pub struct ChannelInfo {
 impl fmt::Display for ChannelInfo {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                write!(f, "features: {}, node_one: {}, one_to_two: {:?}, node_two: {}, two_to_one: {:?}",
-                  log_bytes!(self.features.encode()), log_pubkey!(self.node_one), self.one_to_two, log_pubkey!(self.node_two), self.two_to_one)?;
+                  log_bytes!(self.features.encode()), log_bytes!(self.node_one.as_slice()), self.one_to_two, log_bytes!(self.node_two.as_slice()), self.two_to_one)?;
                Ok(())
        }
 }
@@ -512,7 +650,7 @@ impl_writeable_tlv_based!(ChannelInfo, {
 
 
 /// Fees for routing via a given channel or a node
-#[derive(Eq, PartialEq, Copy, Clone, Debug)]
+#[derive(Eq, PartialEq, Copy, Clone, Debug, Hash)]
 pub struct RoutingFees {
        /// Flat routing fee in satoshis
        pub base_msat: u32,
@@ -591,17 +729,19 @@ 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> {
+       fn write<W: Writer>(&self, writer: &mut W) -> Result<(), 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() {
+               let channels = self.channels.read().unwrap();
+               (channels.len() as u64).write(writer)?;
+               for (ref chan_id, ref chan_info) in channels.iter() {
                        (*chan_id).write(writer)?;
                        chan_info.write(writer)?;
                }
-               (self.nodes.len() as u64).write(writer)?;
-               for (ref node_id, ref node_info) in self.nodes.iter() {
+               let nodes = self.nodes.read().unwrap();
+               (nodes.len() as u64).write(writer)?;
+               for (ref node_id, ref node_info) in nodes.iter() {
                        node_id.write(writer)?;
                        node_info.write(writer)?;
                }
@@ -612,7 +752,7 @@ impl Writeable for NetworkGraph {
 }
 
 impl Readable for NetworkGraph {
-       fn read<R: ::std::io::Read>(reader: &mut R) -> Result<NetworkGraph, DecodeError> {
+       fn read<R: io::Read>(reader: &mut R) -> Result<NetworkGraph, DecodeError> {
                let _ver = read_ver_prefix!(reader, SERIALIZATION_VERSION);
 
                let genesis_hash: BlockHash = Readable::read(reader)?;
@@ -634,8 +774,8 @@ impl Readable for NetworkGraph {
 
                Ok(NetworkGraph {
                        genesis_hash,
-                       channels,
-                       nodes,
+                       channels: RwLock::new(channels),
+                       nodes: RwLock::new(nodes),
                })
        }
 }
@@ -643,47 +783,42 @@ impl Readable for NetworkGraph {
 impl fmt::Display for NetworkGraph {
        fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                writeln!(f, "Network map\n[Channels]")?;
-               for (key, val) in self.channels.iter() {
+               for (key, val) in self.channels.read().unwrap().iter() {
                        writeln!(f, " {}: {}", key, val)?;
                }
                writeln!(f, "[Nodes]")?;
-               for (key, val) in self.nodes.iter() {
-                       writeln!(f, " {}: {}", log_pubkey!(key), val)?;
+               for (&node_id, val) in self.nodes.read().unwrap().iter() {
+                       writeln!(f, " {}: {}", log_bytes!(node_id.as_slice()), val)?;
                }
                Ok(())
        }
 }
 
-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() {
-                               return Some(&node_info.addresses)
-                       }
-               }
-               None
+impl PartialEq for NetworkGraph {
+       fn eq(&self, other: &Self) -> bool {
+               self.genesis_hash == other.genesis_hash &&
+                       *self.channels.read().unwrap() == *other.channels.read().unwrap() &&
+                       *self.nodes.read().unwrap() == *other.nodes.read().unwrap()
        }
+}
 
+impl NetworkGraph {
        /// Creates a new, empty, network graph.
        pub fn new(genesis_hash: BlockHash) -> NetworkGraph {
                Self {
                        genesis_hash,
-                       channels: BTreeMap::new(),
-                       nodes: BTreeMap::new(),
+                       channels: RwLock::new(BTreeMap::new()),
+                       nodes: RwLock::new(BTreeMap::new()),
+               }
+       }
+
+       /// Returns a read-only view of the network graph.
+       pub fn read_only(&'_ self) -> ReadOnlyNetworkGraph<'_> {
+               let channels = self.channels.read().unwrap();
+               let nodes = self.nodes.read().unwrap();
+               ReadOnlyNetworkGraph {
+                       channels,
+                       nodes,
                }
        }
 
@@ -693,7 +828,7 @@ impl NetworkGraph {
        /// 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> {
+       pub fn update_node_from_announcement<T: secp256k1::Verification>(&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))
@@ -703,17 +838,22 @@ impl NetworkGraph {
        /// 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> {
+       pub fn update_node_from_unsigned_announcement(&self, msg: &msgs::UnsignedNodeAnnouncement) -> Result<(), LightningError> {
                self.update_node_from_announcement_intern(msg, None)
        }
 
-       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) {
+       fn update_node_from_announcement_intern(&self, msg: &msgs::UnsignedNodeAnnouncement, full_msg: Option<&msgs::NodeAnnouncement>) -> Result<(), LightningError> {
+               match self.nodes.write().unwrap().get_mut(&NodeId::from_pubkey(&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.timestamp {
-                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
+                                       // The timestamp field is somewhat of a misnomer - the BOLTs use it to order
+                                       // updates to ensure you always have the latest one, only vaguely suggesting
+                                       // that it be at least the current time.
+                                       if node_info.last_update  > msg.timestamp {
+                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Gossip)});
+                                       } else if node_info.last_update  == msg.timestamp {
+                                               return Err(LightningError{err: "Update had the same timestamp as last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                        }
                                }
 
@@ -743,10 +883,12 @@ impl NetworkGraph {
        ///
        /// 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 {
+       pub fn update_channel_from_announcement<T: secp256k1::Verification, C: Deref>(
+               &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);
@@ -761,17 +903,21 @@ impl NetworkGraph {
        ///
        /// 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 {
+       pub fn update_channel_from_unsigned_announcement<C: Deref>(
+               &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 {
+       fn update_channel_from_unsigned_announcement_intern<C: Deref>(
+               &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});
                }
@@ -808,16 +954,18 @@ impl NetworkGraph {
 
                let chan_info = ChannelInfo {
                                features: msg.features.clone(),
-                               node_one: msg.node_id_1.clone(),
+                               node_one: NodeId::from_pubkey(&msg.node_id_1),
                                one_to_two: None,
-                               node_two: msg.node_id_2.clone(),
+                               node_two: NodeId::from_pubkey(&msg.node_id_2),
                                two_to_one: None,
                                capacity_sats: utxo_value,
                                announcement_message: if msg.excess_data.len() <= MAX_EXCESS_BYTES_FOR_RELAY
                                        { full_msg.cloned() } else { None },
                        };
 
-               match self.channels.entry(msg.short_channel_id) {
+               let mut channels = self.channels.write().unwrap();
+               let mut nodes = self.nodes.write().unwrap();
+               match 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
@@ -831,10 +979,10 @@ 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.short_channel_id);
+                                       Self::remove_channel_in_nodes(&mut 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::IgnoreDuplicateGossip});
                                }
                        },
                        BtreeEntry::Vacant(entry) => {
@@ -844,7 +992,7 @@ impl NetworkGraph {
 
                macro_rules! add_channel_to_node {
                        ( $node_id: expr ) => {
-                               match self.nodes.entry($node_id) {
+                               match nodes.entry($node_id) {
                                        BtreeEntry::Occupied(node_entry) => {
                                                node_entry.into_mut().channels.push(msg.short_channel_id);
                                        },
@@ -859,8 +1007,8 @@ impl NetworkGraph {
                        };
                }
 
-               add_channel_to_node!(msg.node_id_1);
-               add_channel_to_node!(msg.node_id_2);
+               add_channel_to_node!(NodeId::from_pubkey(&msg.node_id_1));
+               add_channel_to_node!(NodeId::from_pubkey(&msg.node_id_2));
 
                Ok(())
        }
@@ -869,13 +1017,15 @@ impl NetworkGraph {
        /// If permanent, removes a channel from the local storage.
        /// May cause the removal of nodes too, if this was their last channel.
        /// If not permanent, makes channels unavailable for routing.
-       pub fn close_channel_from_update(&mut self, short_channel_id: u64, is_permanent: bool) {
+       pub fn close_channel_from_update(&self, short_channel_id: u64, is_permanent: bool) {
+               let mut channels = self.channels.write().unwrap();
                if is_permanent {
-                       if let Some(chan) = self.channels.remove(&short_channel_id) {
-                               Self::remove_channel_in_nodes(&mut self.nodes, &chan, short_channel_id);
+                       if let Some(chan) = channels.remove(&short_channel_id) {
+                               let mut nodes = self.nodes.write().unwrap();
+                               Self::remove_channel_in_nodes(&mut nodes, &chan, short_channel_id);
                        }
                } else {
-                       if let Some(chan) = self.channels.get_mut(&short_channel_id) {
+                       if let Some(chan) = channels.get_mut(&short_channel_id) {
                                if let Some(one_to_two) = chan.one_to_two.as_mut() {
                                        one_to_two.enabled = false;
                                }
@@ -886,7 +1036,8 @@ impl NetworkGraph {
                }
        }
 
-       fn fail_node(&mut self, _node_id: &PublicKey, is_permanent: bool) {
+       /// Marks a node in the graph as failed.
+       pub fn fail_node(&self, _node_id: &PublicKey, is_permanent: bool) {
                if is_permanent {
                        // TODO: Wholly remove the node
                } else {
@@ -900,23 +1051,24 @@ impl NetworkGraph {
        /// 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> {
+       pub fn update_channel<T: secp256k1::Verification>(&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> {
+       pub fn update_channel_unsigned(&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> {
+       fn update_channel_intern<T: secp256k1::Verification>(&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.flags & (1 << 1) != (1 << 1);
                let chan_was_enabled;
 
-               match self.channels.get_mut(&msg.short_channel_id) {
+               let mut channels = self.channels.write().unwrap();
+               match 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 {
@@ -935,8 +1087,16 @@ impl NetworkGraph {
                                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.timestamp {
-                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreError});
+                                                       // The timestamp field is somewhat of a misnomer - the BOLTs use it to
+                                                       // order updates to ensure you always have the latest one, only
+                                                       // suggesting  that it be at least the current time. For
+                                                       // channel_updates specifically, the BOLTs discuss the possibility of
+                                                       // pruning based on the timestamp field being more than two weeks old,
+                                                       // but only in the non-normative section.
+                                                       if existing_chan_info.last_update > msg.timestamp {
+                                                               return Err(LightningError{err: "Update older than last processed update".to_owned(), action: ErrorAction::IgnoreAndLog(Level::Gossip)});
+                                                       } else if existing_chan_info.last_update == msg.timestamp {
+                                                               return Err(LightningError{err: "Update had same timestamp as last processed update".to_owned(), action: ErrorAction::IgnoreDuplicateGossip});
                                                        }
                                                        chan_was_enabled = existing_chan_info.enabled;
                                                } else {
@@ -966,21 +1126,28 @@ impl NetworkGraph {
                                if msg.flags & 1 == 1 {
                                        dest_node_id = channel.node_one.clone();
                                        if let Some((sig, ctx)) = sig_info {
-                                               secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_two);
+                                               secp_verify_sig!(ctx, &msg_hash, &sig, &PublicKey::from_slice(channel.node_two.as_slice()).map_err(|_| LightningError{
+                                                       err: "Couldn't parse source node pubkey".to_owned(),
+                                                       action: ErrorAction::IgnoreAndLog(Level::Debug)
+                                               })?);
                                        }
                                        maybe_update_channel_info!(channel.two_to_one, channel.node_two);
                                } else {
                                        dest_node_id = channel.node_two.clone();
                                        if let Some((sig, ctx)) = sig_info {
-                                               secp_verify_sig!(ctx, &msg_hash, &sig, &channel.node_one);
+                                               secp_verify_sig!(ctx, &msg_hash, &sig, &PublicKey::from_slice(channel.node_one.as_slice()).map_err(|_| LightningError{
+                                                       err: "Couldn't parse destination node pubkey".to_owned(),
+                                                       action: ErrorAction::IgnoreAndLog(Level::Debug)
+                                               })?);
                                        }
                                        maybe_update_channel_info!(channel.one_to_two, channel.node_one);
                                }
                        }
                }
 
+               let mut nodes = self.nodes.write().unwrap();
                if chan_enabled {
-                       let node = self.nodes.get_mut(&dest_node_id).unwrap();
+                       let node = nodes.get_mut(&dest_node_id).unwrap();
                        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 {
@@ -992,11 +1159,11 @@ impl NetworkGraph {
                                proportional_millionths
                        });
                } else if chan_was_enabled {
-                       let node = self.nodes.get_mut(&dest_node_id).unwrap();
+                       let node = nodes.get_mut(&dest_node_id).unwrap();
                        let mut lowest_inbound_channel_fees = None;
 
                        for chan_id in node.channels.iter() {
-                               let chan = self.channels.get(chan_id).unwrap();
+                               let chan = channels.get(chan_id).unwrap();
                                let chan_info_opt;
                                if chan.node_one == dest_node_id {
                                        chan_info_opt = chan.two_to_one.as_ref();
@@ -1019,7 +1186,7 @@ impl NetworkGraph {
                Ok(())
        }
 
-       fn remove_channel_in_nodes(nodes: &mut BTreeMap<PublicKey, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
+       fn remove_channel_in_nodes(nodes: &mut BTreeMap<NodeId, NodeInfo>, chan: &ChannelInfo, short_channel_id: u64) {
                macro_rules! remove_from_node {
                        ($node_id: expr) => {
                                if let BtreeEntry::Occupied(mut entry) = nodes.entry($node_id) {
@@ -1040,18 +1207,47 @@ impl NetworkGraph {
        }
 }
 
+impl ReadOnlyNetworkGraph<'_> {
+       /// 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 channels(&self) -> &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 nodes(&self) -> &BTreeMap<NodeId, 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.
+       pub fn get_addresses(&self, pubkey: &PublicKey) -> Option<Vec<NetAddress>> {
+               if let Some(node) = self.nodes.get(&NodeId::from_pubkey(&pubkey)) {
+                       if let Some(node_info) = node.announcement_info.as_ref() {
+                               return Some(node_info.addresses.clone())
+                       }
+               }
+               None
+       }
+}
+
 #[cfg(test)]
 mod tests {
        use chain;
+       use ln::PaymentHash;
        use ln::features::{ChannelFeatures, InitFeatures, NodeFeatures};
-       use routing::network_graph::{NetGraphMsgHandler, NetworkGraph, MAX_EXCESS_BYTES_FOR_RELAY};
+       use routing::network_graph::{NetGraphMsgHandler, NetworkGraph, NetworkUpdate, MAX_EXCESS_BYTES_FOR_RELAY};
        use ln::msgs::{Init, OptionalField, RoutingMessageHandler, UnsignedNodeAnnouncement, NodeAnnouncement,
-               UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate, HTLCFailChannelUpdate,
+               UnsignedChannelAnnouncement, ChannelAnnouncement, UnsignedChannelUpdate, ChannelUpdate, 
                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::events::{Event, EventHandler, MessageSendEvent, MessageSendEventsProvider};
        use util::scid_utils::scid_from_parts;
 
        use bitcoin::hashes::sha256d::Hash as Sha256dHash;
@@ -1067,20 +1263,28 @@ mod tests {
        use bitcoin::secp256k1::key::{PublicKey, SecretKey};
        use bitcoin::secp256k1::{All, Secp256k1};
 
+       use io;
        use prelude::*;
-       use std::sync::Arc;
+       use sync::Arc;
+
+       fn create_network_graph() -> NetworkGraph {
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               NetworkGraph::new(genesis_hash)
+       }
 
-       fn create_net_graph_msg_handler() -> (Secp256k1<All>, NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>) {
+       fn create_net_graph_msg_handler(network_graph: &NetworkGraph) -> (
+               Secp256k1<All>, NetGraphMsgHandler<&NetworkGraph, Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>
+       ) {
                let secp_ctx = Secp256k1::new();
                let logger = Arc::new(test_utils::TestLogger::new());
-               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
-               let net_graph_msg_handler = NetGraphMsgHandler::new(genesis_hash, None, Arc::clone(&logger));
+               let net_graph_msg_handler = NetGraphMsgHandler::new(network_graph, None, Arc::clone(&logger));
                (secp_ctx, net_graph_msg_handler)
        }
 
        #[test]
        fn request_full_sync_finite_times() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                let node_id = PublicKey::from_secret_key(&secp_ctx, &SecretKey::from_slice(&hex::decode("0202020202020202020202020202020202020202020202020202020202020202").unwrap()[..]).unwrap());
 
                assert!(net_graph_msg_handler.should_request_full_sync(&node_id));
@@ -1093,7 +1297,8 @@ mod tests {
 
        #[test]
        fn handling_node_announcements() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
 
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
@@ -1235,18 +1440,18 @@ mod tests {
                };
 
                // Test if the UTXO lookups were not supported
-               let mut net_graph_msg_handler = NetGraphMsgHandler::new(genesis_block(Network::Testnet).header.block_hash(), None, Arc::clone(&logger));
+               let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
+               let mut net_graph_msg_handler = NetGraphMsgHandler::new(&network_graph, None, Arc::clone(&logger));
                match net_graph_msg_handler.handle_channel_announcement(&valid_announcement) {
                        Ok(res) => assert!(res),
                        _ => panic!()
                };
 
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&unsigned_announcement.short_channel_id) {
+                       match network_graph.read_only().channels().get(&unsigned_announcement.short_channel_id) {
                                None => panic!(),
                                Some(_) => ()
-                       }
+                       };
                }
 
                // If we receive announcement for the same channel (with UTXO lookups disabled),
@@ -1259,7 +1464,8 @@ mod tests {
                // Test if an associated transaction were not on-chain (or not confirmed).
                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));
+               let network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
+               net_graph_msg_handler = NetGraphMsgHandler::new(&network_graph, Some(chain_source.clone()), Arc::clone(&logger));
                unsigned_announcement.short_channel_id += 1;
 
                msghash = hash_to_message!(&Sha256dHash::hash(&unsigned_announcement.encode()[..])[..]);
@@ -1294,11 +1500,10 @@ mod tests {
                };
 
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&unsigned_announcement.short_channel_id) {
+                       match network_graph.read_only().channels().get(&unsigned_announcement.short_channel_id) {
                                None => panic!(),
                                Some(_) => ()
-                       }
+                       };
                }
 
                // If we receive announcement for the same channel (but TX is not confirmed),
@@ -1325,13 +1530,12 @@ mod tests {
                        _ => panic!()
                };
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&unsigned_announcement.short_channel_id) {
+                       match network_graph.read_only().channels().get(&unsigned_announcement.short_channel_id) {
                                Some(channel_entry) => {
                                        assert_eq!(channel_entry.features, ChannelFeatures::empty());
                                },
                                _ => panic!()
-                       }
+                       };
                }
 
                // Don't relay valid channels with excess data
@@ -1383,7 +1587,8 @@ mod tests {
                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 network_graph = NetworkGraph::new(genesis_block(Network::Testnet).header.block_hash());
+               let net_graph_msg_handler = NetGraphMsgHandler::new(&network_graph, 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();
@@ -1455,14 +1660,13 @@ mod tests {
                };
 
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&short_channel_id) {
+                       match network_graph.read_only().channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
                                        assert_eq!(channel_info.one_to_two.as_ref().unwrap().cltv_expiry_delta, 144);
                                        assert!(channel_info.two_to_one.is_none());
                                }
-                       }
+                       };
                }
 
                unsigned_channel_update.timestamp += 100;
@@ -1529,7 +1733,7 @@ mod tests {
 
                match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
                        Ok(_) => panic!(),
-                       Err(e) => assert_eq!(e.err, "Update older than last processed update")
+                       Err(e) => assert_eq!(e.err, "Update had same timestamp as last processed update")
                };
                unsigned_channel_update.timestamp += 500;
 
@@ -1547,8 +1751,14 @@ mod tests {
        }
 
        #[test]
-       fn handling_htlc_fail_channel_update() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+       fn handling_network_update() {
+               let logger = test_utils::TestLogger::new();
+               let chain_source = Arc::new(test_utils::TestChainSource::new(Network::Testnet));
+               let genesis_hash = genesis_block(Network::Testnet).header.block_hash();
+               let network_graph = NetworkGraph::new(genesis_hash);
+               let net_graph_msg_handler = NetGraphMsgHandler::new(&network_graph, Some(chain_source.clone()), &logger);
+               let secp_ctx = Secp256k1::new();
+
                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);
@@ -1561,8 +1771,7 @@ mod tests {
 
                {
                        // There is no nodes in the table at the beginning.
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       assert_eq!(network.get_nodes().len(), 0);
+                       assert_eq!(network_graph.read_only().nodes().len(), 0);
                }
 
                {
@@ -1586,10 +1795,9 @@ mod tests {
                                bitcoin_signature_2: secp_ctx.sign(&msghash, node_2_btckey),
                                contents: unsigned_announcement.clone(),
                        };
-                       match net_graph_msg_handler.handle_channel_announcement(&valid_channel_announcement) {
-                               Ok(_) => (),
-                               Err(_) => panic!()
-                       };
+                       let chain_source: Option<&test_utils::TestChainSource> = None;
+                       assert!(network_graph.update_channel_from_announcement(&valid_channel_announcement, &chain_source, &secp_ctx).is_ok());
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).is_some());
 
                        let unsigned_channel_update = UnsignedChannelUpdate {
                                chain_hash,
@@ -1609,61 +1817,88 @@ mod tests {
                                contents: unsigned_channel_update.clone()
                        };
 
-                       match net_graph_msg_handler.handle_channel_update(&valid_channel_update) {
-                               Ok(res) => assert!(res),
-                               _ => panic!()
-                       };
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_none());
+
+                       net_graph_msg_handler.handle_event(&Event::PaymentPathFailed {
+                               payment_id: None,
+                               payment_hash: PaymentHash([0; 32]),
+                               rejected_by_dest: false,
+                               all_paths_failed: true,
+                               path: vec![],
+                               network_update: Some(NetworkUpdate::ChannelUpdateMessage {
+                                       msg: valid_channel_update,
+                               }),
+                               short_channel_id: None,
+                               retry: None,
+                               error_code: None,
+                               error_data: None,
+                       });
+
+                       assert!(network_graph.read_only().channels().get(&short_channel_id).unwrap().one_to_two.is_some());
                }
 
                // Non-permanent closing just disables a channel
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&short_channel_id) {
+                       match network_graph.read_only().channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
-                                       assert!(channel_info.one_to_two.is_some());
+                                       assert!(channel_info.one_to_two.as_ref().unwrap().enabled);
                                }
-                       }
-               }
-
-               let channel_close_msg = HTLCFailChannelUpdate::ChannelClosed {
-                       short_channel_id,
-                       is_permanent: false
-               };
+                       };
 
-               net_graph_msg_handler.handle_htlc_fail_channel_update(&channel_close_msg);
+                       net_graph_msg_handler.handle_event(&Event::PaymentPathFailed {
+                               payment_id: None,
+                               payment_hash: PaymentHash([0; 32]),
+                               rejected_by_dest: false,
+                               all_paths_failed: true,
+                               path: vec![],
+                               network_update: Some(NetworkUpdate::ChannelClosed {
+                                       short_channel_id,
+                                       is_permanent: false,
+                               }),
+                               short_channel_id: None,
+                               retry: None,
+                               error_code: None,
+                               error_data: None,
+                       });
 
-               // Non-permanent closing just disables a channel
-               {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       match network.get_channels().get(&short_channel_id) {
+                       match network_graph.read_only().channels().get(&short_channel_id) {
                                None => panic!(),
                                Some(channel_info) => {
                                        assert!(!channel_info.one_to_two.as_ref().unwrap().enabled);
                                }
-                       }
+                       };
                }
 
-               let channel_close_msg = HTLCFailChannelUpdate::ChannelClosed {
-                       short_channel_id,
-                       is_permanent: true
-               };
-
-               net_graph_msg_handler.handle_htlc_fail_channel_update(&channel_close_msg);
-
                // Permanent closing deletes a channel
                {
-                       let network = net_graph_msg_handler.network_graph.read().unwrap();
-                       assert_eq!(network.get_channels().len(), 0);
+                       net_graph_msg_handler.handle_event(&Event::PaymentPathFailed {
+                               payment_id: None,
+                               payment_hash: PaymentHash([0; 32]),
+                               rejected_by_dest: false,
+                               all_paths_failed: true,
+                               path: vec![],
+                               network_update: Some(NetworkUpdate::ChannelClosed {
+                                       short_channel_id,
+                                       is_permanent: true,
+                               }),
+                               short_channel_id: None,
+                               retry: None,
+                               error_code: None,
+                               error_data: None,
+                       });
+
+                       assert_eq!(network_graph.read_only().channels().len(), 0);
                        // Nodes are also deleted because there are no associated channels anymore
-                       assert_eq!(network.get_nodes().len(), 0);
+                       assert_eq!(network_graph.read_only().nodes().len(), 0);
                }
-               // TODO: Test HTLCFailChannelUpdate::NodeFailure, which is not implemented yet.
+               // TODO: Test NetworkUpdate::NodeFailure, which is not implemented yet.
        }
 
        #[test]
        fn getting_next_channel_announcements() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                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);
@@ -1797,7 +2032,8 @@ mod tests {
 
        #[test]
        fn getting_next_node_announcements() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                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);
@@ -1914,7 +2150,8 @@ mod tests {
 
        #[test]
        fn network_graph_serialization() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
 
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_2_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
@@ -1971,17 +2208,17 @@ mod tests {
                        Err(_) => panic!()
                };
 
-               let network = net_graph_msg_handler.network_graph.write().unwrap();
                let mut w = test_utils::TestVecWriter(Vec::new());
-               assert!(!network.get_nodes().is_empty());
-               assert!(!network.get_channels().is_empty());
-               network.write(&mut w).unwrap();
-               assert!(<NetworkGraph>::read(&mut ::std::io::Cursor::new(&w.0)).unwrap() == *network);
+               assert!(!network_graph.read_only().nodes().is_empty());
+               assert!(!network_graph.read_only().channels().is_empty());
+               network_graph.write(&mut w).unwrap();
+               assert!(<NetworkGraph>::read(&mut io::Cursor::new(&w.0)).unwrap() == network_graph);
        }
 
        #[test]
        fn calling_sync_routing_table() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);
 
@@ -2018,7 +2255,8 @@ mod tests {
                // 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 network_graph = create_network_graph();
+                       let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                        let init_msg = Init { features: InitFeatures::known() };
                        for n in 1..7 {
                                let node_privkey = &SecretKey::from_slice(&[n; 32]).unwrap();
@@ -2037,7 +2275,8 @@ mod tests {
 
        #[test]
        fn handling_reply_channel_range() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                let node_privkey_1 = &SecretKey::from_slice(&[42; 32]).unwrap();
                let node_id_1 = PublicKey::from_secret_key(&secp_ctx, node_privkey_1);
 
@@ -2085,7 +2324,8 @@ mod tests {
 
        #[test]
        fn handling_reply_short_channel_ids() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);
 
@@ -2114,7 +2354,8 @@ mod tests {
 
        #[test]
        fn handling_query_channel_range() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
 
                let chain_hash = genesis_block(Network::Testnet).header.block_hash();
                let node_1_privkey = &SecretKey::from_slice(&[42; 32]).unwrap();
@@ -2235,8 +2476,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 0x01000000,
+                                       first_blocknum: 0xffffff,
+                                       number_of_blocks: 1,
                                        sync_complete: true,
                                        short_channel_ids: vec![]
                                },
@@ -2256,8 +2497,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 2000,
+                                       first_blocknum: 1000,
+                                       number_of_blocks: 1000,
                                        sync_complete: true,
                                        short_channel_ids: vec![],
                                }
@@ -2277,8 +2518,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 0xffffffff,
+                                       first_blocknum: 0xfe0000,
+                                       number_of_blocks: 0xffffffff - 0xfe0000,
                                        sync_complete: true,
                                        short_channel_ids: vec![
                                                0xfffffe_ffffff_ffff, // max
@@ -2300,8 +2541,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 108000,
+                                       first_blocknum: 100000,
+                                       number_of_blocks: 8000,
                                        sync_complete: true,
                                        short_channel_ids: (100000..=107999)
                                                .map(|block| scid_from_parts(block, 0, 0).unwrap())
@@ -2323,8 +2564,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 108000,
+                                       first_blocknum: 100000,
+                                       number_of_blocks: 7999,
                                        sync_complete: false,
                                        short_channel_ids: (100000..=107999)
                                                .map(|block| scid_from_parts(block, 0, 0).unwrap())
@@ -2332,8 +2573,8 @@ mod tests {
                                },
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 108001,
+                                       first_blocknum: 107999,
+                                       number_of_blocks: 2,
                                        sync_complete: true,
                                        short_channel_ids: vec![
                                                scid_from_parts(108000, 0, 0).unwrap(),
@@ -2355,8 +2596,8 @@ mod tests {
                        vec![
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 108002,
+                                       first_blocknum: 100002,
+                                       number_of_blocks: 7999,
                                        sync_complete: false,
                                        short_channel_ids: (100002..=108001)
                                                .map(|block| scid_from_parts(block, 0, 0).unwrap())
@@ -2364,8 +2605,8 @@ mod tests {
                                },
                                ReplyChannelRange {
                                        chain_hash: chain_hash.clone(),
-                                       first_blocknum: 0,
-                                       number_of_blocks: 108002,
+                                       first_blocknum: 108001,
+                                       number_of_blocks: 1,
                                        sync_complete: true,
                                        short_channel_ids: vec![
                                                scid_from_parts(108001, 1, 0).unwrap(),
@@ -2376,12 +2617,15 @@ mod tests {
        }
 
        fn do_handling_query_channel_range(
-               net_graph_msg_handler: &NetGraphMsgHandler<Arc<test_utils::TestChainSource>, Arc<test_utils::TestLogger>>,
+               net_graph_msg_handler: &NetGraphMsgHandler<&NetworkGraph, 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 {
@@ -2403,6 +2647,17 @@ mod tests {
                                        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"),
                        }
@@ -2411,7 +2666,8 @@ mod tests {
 
        #[test]
        fn handling_query_short_channel_ids() {
-               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler();
+               let network_graph = create_network_graph();
+               let (secp_ctx, net_graph_msg_handler) = create_net_graph_msg_handler(&network_graph);
                let node_privkey = &SecretKey::from_slice(&[41; 32]).unwrap();
                let node_id = PublicKey::from_secret_key(&secp_ctx, node_privkey);