Merge pull request #2045 from wpaulino/fix-broken-commitment-test-vectors
[rust-lightning] / lightning / src / ln / peer_handler.rs
index 89862f29fec2568ca66151ea498c685d0402a80b..edc9c68a5068c25b419a5e21dc16a4cb7d850ac9 100644 (file)
@@ -46,16 +46,23 @@ use bitcoin::hashes::sha256::Hash as Sha256;
 use bitcoin::hashes::sha256::HashEngine as Sha256Engine;
 use bitcoin::hashes::{HashEngine, Hash};
 
-/// Handler for BOLT1-compliant messages.
+/// A handler provided to [`PeerManager`] for reading and handling custom messages.
+///
+/// [BOLT 1] specifies a custom message type range for use with experimental or application-specific
+/// messages. `CustomMessageHandler` allows for user-defined handling of such types. See the
+/// [`lightning_custom_message`] crate for tools useful in composing more than one custom handler.
+///
+/// [BOLT 1]: https://github.com/lightning/bolts/blob/master/01-messaging.md
+/// [`lightning_custom_message`]: https://docs.rs/lightning_custom_message/latest/lightning_custom_message
 pub trait CustomMessageHandler: wire::CustomMessageReader {
-       /// Called with the message type that was received and the buffer to be read.
-       /// Can return a `MessageHandlingError` if the message could not be handled.
+       /// Handles the given message sent from `sender_node_id`, possibly producing messages for
+       /// [`CustomMessageHandler::get_and_clear_pending_msg`] to return and thus for [`PeerManager`]
+       /// to send.
        fn handle_custom_message(&self, msg: Self::CustomMessage, sender_node_id: &PublicKey) -> Result<(), LightningError>;
 
-       /// Gets the list of pending messages which were generated by the custom message
-       /// handler, clearing the list in the process. The first tuple element must
-       /// correspond to the intended recipients node ids. If no connection to one of the
-       /// specified node does not exist, the message is simply not sent to it.
+       /// Returns the list of pending messages that were generated by the handler, clearing the list
+       /// in the process. Each message is paired with the node id of the intended recipient. If no
+       /// connection to the node exists, then the message is simply not sent.
        fn get_and_clear_pending_msg(&self) -> Vec<(PublicKey, Self::CustomMessage)>;
 }
 
@@ -72,7 +79,7 @@ impl RoutingMessageHandler for IgnoringMessageHandler {
        fn get_next_channel_announcement(&self, _starting_point: u64) ->
                Option<(msgs::ChannelAnnouncement, Option<msgs::ChannelUpdate>, Option<msgs::ChannelUpdate>)> { None }
        fn get_next_node_announcement(&self, _starting_point: Option<&NodeId>) -> Option<msgs::NodeAnnouncement> { None }
-       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init) -> Result<(), ()> { Ok(()) }
+       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init, _inbound: bool) -> Result<(), ()> { Ok(()) }
        fn handle_reply_channel_range(&self, _their_node_id: &PublicKey, _msg: msgs::ReplyChannelRange) -> Result<(), LightningError> { Ok(()) }
        fn handle_reply_short_channel_ids_end(&self, _their_node_id: &PublicKey, _msg: msgs::ReplyShortChannelIdsEnd) -> Result<(), LightningError> { Ok(()) }
        fn handle_query_channel_range(&self, _their_node_id: &PublicKey, _msg: msgs::QueryChannelRange) -> Result<(), LightningError> { Ok(()) }
@@ -81,14 +88,15 @@ impl RoutingMessageHandler for IgnoringMessageHandler {
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
                InitFeatures::empty()
        }
+       fn processing_queue_high(&self) -> bool { false }
 }
 impl OnionMessageProvider for IgnoringMessageHandler {
        fn next_onion_message_for_peer(&self, _peer_node_id: PublicKey) -> Option<msgs::OnionMessage> { None }
 }
 impl OnionMessageHandler for IgnoringMessageHandler {
        fn handle_onion_message(&self, _their_node_id: &PublicKey, _msg: &msgs::OnionMessage) {}
-       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init) -> Result<(), ()> { Ok(()) }
-       fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}
+       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init, _inbound: bool) -> Result<(), ()> { Ok(()) }
+       fn peer_disconnected(&self, _their_node_id: &PublicKey) {}
        fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
                InitFeatures::empty()
@@ -222,8 +230,8 @@ impl ChannelMessageHandler for ErroringMessageHandler {
        }
        // msgs::ChannelUpdate does not contain the channel_id field, so we just drop them.
        fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &msgs::ChannelUpdate) {}
-       fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}
-       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init) -> Result<(), ()> { Ok(()) }
+       fn peer_disconnected(&self, _their_node_id: &PublicKey) {}
+       fn peer_connected(&self, _their_node_id: &PublicKey, _init: &msgs::Init, _inbound: bool) -> Result<(), ()> { Ok(()) }
        fn handle_error(&self, _their_node_id: &PublicKey, _msg: &msgs::ErrorMessage) {}
        fn provided_node_features(&self) -> NodeFeatures { NodeFeatures::empty() }
        fn provided_init_features(&self, _their_node_id: &PublicKey) -> InitFeatures {
@@ -314,16 +322,7 @@ pub trait SocketDescriptor : cmp::Eq + hash::Hash + Clone {
 /// generate no further read_event/write_buffer_space_avail/socket_disconnected calls for the
 /// descriptor.
 #[derive(Clone)]
-pub struct PeerHandleError {
-       /// Used to indicate that we probably can't make any future connections to this peer (e.g.
-       /// because we required features that our peer was missing, or vice versa).
-       ///
-       /// While LDK's [`ChannelManager`] will not do it automatically, you likely wish to force-close
-       /// any channels with this peer or check for new versions of LDK.
-       ///
-       /// [`ChannelManager`]: crate::ln::channelmanager::ChannelManager
-       pub no_connection_possible: bool,
-}
+pub struct PeerHandleError { }
 impl fmt::Debug for PeerHandleError {
        fn fmt(&self, formatter: &mut fmt::Formatter) -> Result<(), fmt::Error> {
                formatter.write_str("Peer Sent Invalid Data")
@@ -392,6 +391,12 @@ struct Peer {
        /// We cache a `NodeId` here to avoid serializing peers' keys every time we forward gossip
        /// messages in `PeerManager`. Use `Peer::set_their_node_id` to modify this field.
        their_node_id: Option<(PublicKey, NodeId)>,
+       /// The features provided in the peer's [`msgs::Init`] message.
+       ///
+       /// This is set only after we've processed the [`msgs::Init`] message and called relevant
+       /// `peer_connected` handler methods. Thus, this field is set *iff* we've finished our
+       /// handshake and can talk to this peer normally (though use [`Peer::handshake_complete`] to
+       /// check this.
        their_features: Option<InitFeatures>,
        their_net_address: Option<NetAddress>,
 
@@ -414,9 +419,24 @@ struct Peer {
        awaiting_pong_timer_tick_intervals: i8,
        received_message_since_timer_tick: bool,
        sent_gossip_timestamp_filter: bool,
+
+       /// Indicates we've received a `channel_announcement` since the last time we had
+       /// [`PeerManager::gossip_processing_backlogged`] set (or, really, that we've received a
+       /// `channel_announcement` at all - we set this unconditionally but unset it every time we
+       /// check if we're gossip-processing-backlogged).
+       received_channel_announce_since_backlogged: bool,
+
+       inbound_connection: bool,
 }
 
 impl Peer {
+       /// True after we've processed the [`msgs::Init`] message and called relevant `peer_connected`
+       /// handler methods. Thus, this implies we've finished our handshake and can talk to this peer
+       /// normally.
+       fn handshake_complete(&self) -> bool {
+               self.their_features.is_some()
+       }
+
        /// Returns true if the channel announcements/updates for the given channel should be
        /// forwarded to this peer.
        /// If we are sending our routing table to this peer and we have not yet sent channel
@@ -424,6 +444,7 @@ impl Peer {
        /// point and we shouldn't send it yet to avoid sending duplicate updates. If we've already
        /// sent the old versions, we should send the update, and so return true here.
        fn should_forward_channel_announcement(&self, channel_id: u64) -> bool {
+               if !self.handshake_complete() { return false; }
                if self.their_features.as_ref().unwrap().supports_gossip_queries() &&
                        !self.sent_gossip_timestamp_filter {
                                return false;
@@ -437,6 +458,7 @@ impl Peer {
 
        /// Similar to the above, but for node announcements indexed by node_id.
        fn should_forward_node_announcement(&self, node_id: NodeId) -> bool {
+               if !self.handshake_complete() { return false; }
                if self.their_features.as_ref().unwrap().supports_gossip_queries() &&
                        !self.sent_gossip_timestamp_filter {
                                return false;
@@ -450,8 +472,12 @@ impl Peer {
 
        /// Returns whether we should be reading bytes from this peer, based on whether its outbound
        /// buffer still has space and we don't need to pause reads to get some writes out.
-       fn should_read(&self) -> bool {
-               self.pending_outbound_buffer.len() < OUTBOUND_BUFFER_LIMIT_READ_PAUSE
+       fn should_read(&mut self, gossip_processing_backlogged: bool) -> bool {
+               if !gossip_processing_backlogged {
+                       self.received_channel_announce_since_backlogged = false;
+               }
+               self.pending_outbound_buffer.len() < OUTBOUND_BUFFER_LIMIT_READ_PAUSE &&
+                       (!gossip_processing_backlogged || !self.received_channel_announce_since_backlogged)
        }
 
        /// Determines if we should push additional gossip background sync (aka "backfill") onto a peer's
@@ -459,19 +485,20 @@ impl Peer {
        fn should_buffer_gossip_backfill(&self) -> bool {
                self.pending_outbound_buffer.is_empty() && self.gossip_broadcast_buffer.is_empty()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
+                       && self.handshake_complete()
        }
 
        /// Determines if we should push an onion message onto a peer's outbound buffer. This is checked
        /// every time the peer's buffer may have been drained.
        fn should_buffer_onion_message(&self) -> bool {
-               self.pending_outbound_buffer.is_empty()
+               self.pending_outbound_buffer.is_empty() && self.handshake_complete()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
        }
 
        /// Determines if we should push additional gossip broadcast messages onto a peer's outbound
        /// buffer. This is checked every time the peer's buffer may have been drained.
        fn should_buffer_gossip_broadcast(&self) -> bool {
-               self.pending_outbound_buffer.is_empty()
+               self.pending_outbound_buffer.is_empty() && self.handshake_complete()
                        && self.msgs_sent_since_pong < BUFFER_DRAIN_MSGS_PER_TICK
        }
 
@@ -568,6 +595,9 @@ pub struct PeerManager<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: D
 
        peer_counter: AtomicCounter,
 
+       gossip_processing_backlogged: AtomicBool,
+       gossip_processing_backlog_lifted: AtomicBool,
+
        node_signer: NS,
 
        logger: L,
@@ -726,6 +756,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        blocked_event_processors: AtomicBool::new(false),
                        ephemeral_key_midstate,
                        peer_counter: AtomicCounter::new(),
+                       gossip_processing_backlogged: AtomicBool::new(false),
+                       gossip_processing_backlog_lifted: AtomicBool::new(false),
                        last_node_announcement_serial: AtomicU32::new(current_time),
                        logger,
                        custom_message_handler,
@@ -734,20 +766,25 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                }
        }
 
-       /// Get the list of node ids for peers which have completed the initial handshake.
+       /// Get a list of tuples mapping from node id to network addresses for peers which have
+       /// completed the initial handshake.
+       ///
+       /// For outbound connections, the [`PublicKey`] will be the same as the `their_node_id` parameter
+       /// passed in to [`Self::new_outbound_connection`], however entries will only appear once the initial
+       /// handshake has completed and we are sure the remote peer has the private key for the given
+       /// [`PublicKey`].
        ///
-       /// For outbound connections, this will be the same as the their_node_id parameter passed in to
-       /// new_outbound_connection, however entries will only appear once the initial handshake has
-       /// completed and we are sure the remote peer has the private key for the given node_id.
-       pub fn get_peer_node_ids(&self) -> Vec<PublicKey> {
+       /// The returned `Option`s will only be `Some` if an address had been previously given via
+       /// [`Self::new_outbound_connection`] or [`Self::new_inbound_connection`].
+       pub fn get_peer_node_ids(&self) -> Vec<(PublicKey, Option<NetAddress>)> {
                let peers = self.peers.read().unwrap();
                peers.values().filter_map(|peer_mutex| {
                        let p = peer_mutex.lock().unwrap();
-                       if !p.channel_encryptor.is_ready_for_encryption() || p.their_features.is_none() {
+                       if !p.handshake_complete() {
                                return None;
                        }
-                       p.their_node_id
-               }).map(|(node_id, _)| node_id).collect()
+                       Some((p.their_node_id.unwrap().0, p.their_net_address.clone()))
+               }).collect()
        }
 
        fn get_ephemeral_key(&self) -> SecretKey {
@@ -757,7 +794,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                SecretKey::from_slice(&Sha256::from_engine(ephemeral_hash).into_inner()).expect("You broke SHA-256!")
        }
 
-       /// Indicates a new outbound connection has been established to a node with the given node_id
+       /// Indicates a new outbound connection has been established to a node with the given `node_id`
        /// and an optional remote network address.
        ///
        /// The remote network address adds the option to report a remote IP address back to a connecting
@@ -778,31 +815,40 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                let pending_read_buffer = [0; 50].to_vec(); // Noise act two is 50 bytes
 
                let mut peers = self.peers.write().unwrap();
-               if peers.insert(descriptor, Mutex::new(Peer {
-                       channel_encryptor: peer_encryptor,
-                       their_node_id: None,
-                       their_features: None,
-                       their_net_address: remote_network_address,
-
-                       pending_outbound_buffer: LinkedList::new(),
-                       pending_outbound_buffer_first_msg_offset: 0,
-                       gossip_broadcast_buffer: LinkedList::new(),
-                       awaiting_write_event: false,
-
-                       pending_read_buffer,
-                       pending_read_buffer_pos: 0,
-                       pending_read_is_header: false,
-
-                       sync_status: InitSyncTracker::NoSyncRequested,
-
-                       msgs_sent_since_pong: 0,
-                       awaiting_pong_timer_tick_intervals: 0,
-                       received_message_since_timer_tick: false,
-                       sent_gossip_timestamp_filter: false,
-               })).is_some() {
-                       panic!("PeerManager driver duplicated descriptors!");
-               };
-               Ok(res)
+               match peers.entry(descriptor) {
+                       hash_map::Entry::Occupied(_) => {
+                               debug_assert!(false, "PeerManager driver duplicated descriptors!");
+                               Err(PeerHandleError {})
+                       },
+                       hash_map::Entry::Vacant(e) => {
+                               e.insert(Mutex::new(Peer {
+                                       channel_encryptor: peer_encryptor,
+                                       their_node_id: None,
+                                       their_features: None,
+                                       their_net_address: remote_network_address,
+
+                                       pending_outbound_buffer: LinkedList::new(),
+                                       pending_outbound_buffer_first_msg_offset: 0,
+                                       gossip_broadcast_buffer: LinkedList::new(),
+                                       awaiting_write_event: false,
+
+                                       pending_read_buffer,
+                                       pending_read_buffer_pos: 0,
+                                       pending_read_is_header: false,
+
+                                       sync_status: InitSyncTracker::NoSyncRequested,
+
+                                       msgs_sent_since_pong: 0,
+                                       awaiting_pong_timer_tick_intervals: 0,
+                                       received_message_since_timer_tick: false,
+                                       sent_gossip_timestamp_filter: false,
+
+                                       received_channel_announce_since_backlogged: false,
+                                       inbound_connection: false,
+                               }));
+                               Ok(res)
+                       }
+               }
        }
 
        /// Indicates a new inbound connection has been established to a node with an optional remote
@@ -825,34 +871,56 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                let pending_read_buffer = [0; 50].to_vec(); // Noise act one is 50 bytes
 
                let mut peers = self.peers.write().unwrap();
-               if peers.insert(descriptor, Mutex::new(Peer {
-                       channel_encryptor: peer_encryptor,
-                       their_node_id: None,
-                       their_features: None,
-                       their_net_address: remote_network_address,
-
-                       pending_outbound_buffer: LinkedList::new(),
-                       pending_outbound_buffer_first_msg_offset: 0,
-                       gossip_broadcast_buffer: LinkedList::new(),
-                       awaiting_write_event: false,
-
-                       pending_read_buffer,
-                       pending_read_buffer_pos: 0,
-                       pending_read_is_header: false,
-
-                       sync_status: InitSyncTracker::NoSyncRequested,
-
-                       msgs_sent_since_pong: 0,
-                       awaiting_pong_timer_tick_intervals: 0,
-                       received_message_since_timer_tick: false,
-                       sent_gossip_timestamp_filter: false,
-               })).is_some() {
-                       panic!("PeerManager driver duplicated descriptors!");
-               };
-               Ok(())
+               match peers.entry(descriptor) {
+                       hash_map::Entry::Occupied(_) => {
+                               debug_assert!(false, "PeerManager driver duplicated descriptors!");
+                               Err(PeerHandleError {})
+                       },
+                       hash_map::Entry::Vacant(e) => {
+                               e.insert(Mutex::new(Peer {
+                                       channel_encryptor: peer_encryptor,
+                                       their_node_id: None,
+                                       their_features: None,
+                                       their_net_address: remote_network_address,
+
+                                       pending_outbound_buffer: LinkedList::new(),
+                                       pending_outbound_buffer_first_msg_offset: 0,
+                                       gossip_broadcast_buffer: LinkedList::new(),
+                                       awaiting_write_event: false,
+
+                                       pending_read_buffer,
+                                       pending_read_buffer_pos: 0,
+                                       pending_read_is_header: false,
+
+                                       sync_status: InitSyncTracker::NoSyncRequested,
+
+                                       msgs_sent_since_pong: 0,
+                                       awaiting_pong_timer_tick_intervals: 0,
+                                       received_message_since_timer_tick: false,
+                                       sent_gossip_timestamp_filter: false,
+
+                                       received_channel_announce_since_backlogged: false,
+                                       inbound_connection: true,
+                               }));
+                               Ok(())
+                       }
+               }
+       }
+
+       fn peer_should_read(&self, peer: &mut Peer) -> bool {
+               peer.should_read(self.gossip_processing_backlogged.load(Ordering::Relaxed))
+       }
+
+       fn update_gossip_backlogged(&self) {
+               let new_state = self.message_handler.route_handler.processing_queue_high();
+               let prev_state = self.gossip_processing_backlogged.swap(new_state, Ordering::Relaxed);
+               if prev_state && !new_state {
+                       self.gossip_processing_backlog_lifted.store(true, Ordering::Relaxed);
+               }
        }
 
-       fn do_attempt_write_data(&self, descriptor: &mut Descriptor, peer: &mut Peer) {
+       fn do_attempt_write_data(&self, descriptor: &mut Descriptor, peer: &mut Peer, force_one_write: bool) {
+               let mut have_written = false;
                while !peer.awaiting_write_event {
                        if peer.should_buffer_onion_message() {
                                if let Some((peer_node_id, _)) = peer.their_node_id {
@@ -909,13 +977,23 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                self.maybe_send_extra_ping(peer);
                        }
 
+                       let should_read = self.peer_should_read(peer);
                        let next_buff = match peer.pending_outbound_buffer.front() {
-                               None => return,
+                               None => {
+                                       if force_one_write && !have_written {
+                                               if should_read {
+                                                       let data_sent = descriptor.send_data(&[], should_read);
+                                                       debug_assert_eq!(data_sent, 0, "Can't write more than no data");
+                                               }
+                                       }
+                                       return
+                               },
                                Some(buff) => buff,
                        };
 
                        let pending = &next_buff[peer.pending_outbound_buffer_first_msg_offset..];
-                       let data_sent = descriptor.send_data(pending, peer.should_read());
+                       let data_sent = descriptor.send_data(pending, should_read);
+                       have_written = true;
                        peer.pending_outbound_buffer_first_msg_offset += data_sent;
                        if peer.pending_outbound_buffer_first_msg_offset == next_buff.len() {
                                peer.pending_outbound_buffer_first_msg_offset = 0;
@@ -945,12 +1023,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                // This is most likely a simple race condition where the user found that the socket
                                // was writeable, then we told the user to `disconnect_socket()`, then they called
                                // this method. Return an error to make sure we get disconnected.
-                               return Err(PeerHandleError { no_connection_possible: false });
+                               return Err(PeerHandleError { });
                        },
                        Some(peer_mutex) => {
                                let mut peer = peer_mutex.lock().unwrap();
                                peer.awaiting_write_event = false;
-                               self.do_attempt_write_data(descriptor, &mut peer);
+                               self.do_attempt_write_data(descriptor, &mut peer, false);
                        }
                };
                Ok(())
@@ -968,6 +1046,9 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
        /// [`send_data`] call on this descriptor has `resume_read` set (preventing DoS issues in the
        /// send buffer).
        ///
+       /// In order to avoid processing too many messages at once per peer, `data` should be on the
+       /// order of 4KiB.
+       ///
        /// [`send_data`]: SocketDescriptor::send_data
        /// [`process_events`]: PeerManager::process_events
        pub fn read_event(&self, peer_descriptor: &mut Descriptor, data: &[u8]) -> Result<bool, PeerHandleError> {
@@ -975,7 +1056,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        Ok(res) => Ok(res),
                        Err(e) => {
                                log_trace!(self.logger, "Peer sent invalid data or we decided to disconnect due to a protocol error");
-                               self.disconnect_event_internal(peer_descriptor, e.no_connection_possible);
+                               self.disconnect_event_internal(peer_descriptor);
                                Err(e)
                        }
                }
@@ -1008,7 +1089,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                // This is most likely a simple race condition where the user read some bytes
                                // from the socket, then we told the user to `disconnect_socket()`, then they
                                // called this method. Return an error to make sure we get disconnected.
-                               return Err(PeerHandleError { no_connection_possible: false });
+                               return Err(PeerHandleError { });
                        },
                        Some(peer_mutex) => {
                                let mut read_pos = 0;
@@ -1022,7 +1103,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                                                msgs::ErrorAction::DisconnectPeer { msg: _ } => {
                                                                                        //TODO: Try to push msg
                                                                                        log_debug!(self.logger, "Error handling message{}; disconnecting peer with: {}", OptionalFromDebugger(&peer_node_id), e.err);
-                                                                                       return Err(PeerHandleError{ no_connection_possible: false });
+                                                                                       return Err(PeerHandleError { });
                                                                                },
                                                                                msgs::ErrorAction::IgnoreAndLog(level) => {
                                                                                        log_given_level!(self.logger, level, "Error handling message{}; ignoring: {}", OptionalFromDebugger(&peer_node_id), e.err);
@@ -1072,10 +1153,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                macro_rules! insert_node_id {
                                                        () => {
                                                                match self.node_id_to_descriptor.lock().unwrap().entry(peer.their_node_id.unwrap().0) {
-                                                                       hash_map::Entry::Occupied(_) => {
+                                                                       hash_map::Entry::Occupied(e) => {
                                                                                log_trace!(self.logger, "Got second connection with {}, closing", log_pubkey!(peer.their_node_id.unwrap().0));
                                                                                peer.their_node_id = None; // Unset so that we don't generate a peer_disconnected event
-                                                                               return Err(PeerHandleError{ no_connection_possible: false })
+                                                                               // Check that the peers map is consistent with the
+                                                                               // node_id_to_descriptor map, as this has been broken
+                                                                               // before.
+                                                                               debug_assert!(peers.get(e.get()).is_some());
+                                                                               return Err(PeerHandleError { })
                                                                        },
                                                                        hash_map::Entry::Vacant(entry) => {
                                                                                log_debug!(self.logger, "Finished noise handshake for connection with {}", log_pubkey!(peer.their_node_id.unwrap().0));
@@ -1132,7 +1217,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                                        if peer.pending_read_buffer.capacity() > 8192 { peer.pending_read_buffer = Vec::new(); }
                                                                        peer.pending_read_buffer.resize(msg_len as usize + 16, 0);
                                                                        if msg_len < 2 { // Need at least the message type tag
-                                                                               return Err(PeerHandleError{ no_connection_possible: false });
+                                                                               return Err(PeerHandleError { });
                                                                        }
                                                                        peer.pending_read_is_header = false;
                                                                } else {
@@ -1175,19 +1260,19 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                                                                (msgs::DecodeError::UnknownRequiredFeature, ty) => {
                                                                                                        log_gossip!(self.logger, "Received a message with an unknown required feature flag or TLV, you may want to update!");
                                                                                                        self.enqueue_message(peer, &msgs::WarningMessage { channel_id: [0; 32], data: format!("Received an unknown required feature/TLV in message type {:?}", ty) });
-                                                                                                       return Err(PeerHandleError { no_connection_possible: false });
+                                                                                                       return Err(PeerHandleError { });
                                                                                                }
-                                                                                               (msgs::DecodeError::UnknownVersion, _) => return Err(PeerHandleError { no_connection_possible: false }),
+                                                                                               (msgs::DecodeError::UnknownVersion, _) => return Err(PeerHandleError { }),
                                                                                                (msgs::DecodeError::InvalidValue, _) => {
                                                                                                        log_debug!(self.logger, "Got an invalid value while deserializing message");
-                                                                                                       return Err(PeerHandleError { no_connection_possible: false });
+                                                                                                       return Err(PeerHandleError { });
                                                                                                }
                                                                                                (msgs::DecodeError::ShortRead, _) => {
                                                                                                        log_debug!(self.logger, "Deserialization failed due to shortness of message");
-                                                                                                       return Err(PeerHandleError { no_connection_possible: false });
+                                                                                                       return Err(PeerHandleError { });
                                                                                                }
-                                                                                               (msgs::DecodeError::BadLengthDescriptor, _) => return Err(PeerHandleError { no_connection_possible: false }),
-                                                                                               (msgs::DecodeError::Io(_), _) => return Err(PeerHandleError { no_connection_possible: false }),
+                                                                                               (msgs::DecodeError::BadLengthDescriptor, _) => return Err(PeerHandleError { }),
+                                                                                               (msgs::DecodeError::Io(_), _) => return Err(PeerHandleError { }),
                                                                                        }
                                                                                }
                                                                        };
@@ -1197,7 +1282,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                        }
                                                }
                                        }
-                                       pause_read = !peer.should_read();
+                                       pause_read = !self.peer_should_read(peer);
 
                                        if let Some(message) = msg_to_handle {
                                                match self.handle_message(&peer_mutex, peer_lock, message) {
@@ -1239,10 +1324,10 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                if let wire::Message::Init(msg) = message {
                        if msg.features.requires_unknown_bits() {
                                log_debug!(self.logger, "Peer features required unknown version bits");
-                               return Err(PeerHandleError{ no_connection_possible: true }.into());
+                               return Err(PeerHandleError { }.into());
                        }
                        if peer_lock.their_features.is_some() {
-                               return Err(PeerHandleError{ no_connection_possible: false }.into());
+                               return Err(PeerHandleError { }.into());
                        }
 
                        log_info!(self.logger, "Received peer Init message from {}: {}", log_pubkey!(their_node_id), msg.features);
@@ -1252,24 +1337,24 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                peer_lock.sync_status = InitSyncTracker::ChannelsSyncing(0);
                        }
 
-                       if let Err(()) = self.message_handler.route_handler.peer_connected(&their_node_id, &msg) {
+                       if let Err(()) = self.message_handler.route_handler.peer_connected(&their_node_id, &msg, peer_lock.inbound_connection) {
                                log_debug!(self.logger, "Route Handler decided we couldn't communicate with peer {}", log_pubkey!(their_node_id));
-                               return Err(PeerHandleError{ no_connection_possible: true }.into());
+                               return Err(PeerHandleError { }.into());
                        }
-                       if let Err(()) = self.message_handler.chan_handler.peer_connected(&their_node_id, &msg) {
+                       if let Err(()) = self.message_handler.chan_handler.peer_connected(&their_node_id, &msg, peer_lock.inbound_connection) {
                                log_debug!(self.logger, "Channel Handler decided we couldn't communicate with peer {}", log_pubkey!(their_node_id));
-                               return Err(PeerHandleError{ no_connection_possible: true }.into());
+                               return Err(PeerHandleError { }.into());
                        }
-                       if let Err(()) = self.message_handler.onion_message_handler.peer_connected(&their_node_id, &msg) {
+                       if let Err(()) = self.message_handler.onion_message_handler.peer_connected(&their_node_id, &msg, peer_lock.inbound_connection) {
                                log_debug!(self.logger, "Onion Message Handler decided we couldn't communicate with peer {}", log_pubkey!(their_node_id));
-                               return Err(PeerHandleError{ no_connection_possible: true }.into());
+                               return Err(PeerHandleError { }.into());
                        }
 
                        peer_lock.their_features = Some(msg.features);
                        return Ok(None);
                } else if peer_lock.their_features.is_none() {
                        log_debug!(self.logger, "Peer {} sent non-Init first message", log_pubkey!(their_node_id));
-                       return Err(PeerHandleError{ no_connection_possible: false }.into());
+                       return Err(PeerHandleError { }.into());
                }
 
                if let wire::Message::GossipTimestampFilter(_msg) = message {
@@ -1283,6 +1368,10 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        return Ok(None);
                }
 
+               if let wire::Message::ChannelAnnouncement(ref _msg) = message {
+                       peer_lock.received_channel_announce_since_backlogged = true;
+               }
+
                mem::drop(peer_lock);
 
                if is_gossip_msg(message.type_id()) {
@@ -1317,7 +1406,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                }
                                self.message_handler.chan_handler.handle_error(&their_node_id, &msg);
                                if msg.channel_id == [0; 32] {
-                                       return Err(PeerHandleError{ no_connection_possible: true }.into());
+                                       return Err(PeerHandleError { }.into());
                                }
                        },
                        wire::Message::Warning(msg) => {
@@ -1409,12 +1498,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::ChannelAnnouncement(msg));
                                }
+                               self.update_gossip_backlogged();
                        },
                        wire::Message::NodeAnnouncement(msg) => {
                                if self.message_handler.route_handler.handle_node_announcement(&msg)
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::NodeAnnouncement(msg));
                                }
+                               self.update_gossip_backlogged();
                        },
                        wire::Message::ChannelUpdate(msg) => {
                                self.message_handler.chan_handler.handle_channel_update(&their_node_id, &msg);
@@ -1422,6 +1513,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::ChannelUpdate(msg));
                                }
+                               self.update_gossip_backlogged();
                        },
                        wire::Message::QueryShortChannelIds(msg) => {
                                self.message_handler.route_handler.handle_query_short_channel_ids(&their_node_id, msg)?;
@@ -1444,8 +1536,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        // Unknown messages:
                        wire::Message::Unknown(type_id) if message.is_even() => {
                                log_debug!(self.logger, "Received unknown even message of type {}, disconnecting peer!", type_id);
-                               // Fail the channel if message is an even, unknown type as per BOLT #1.
-                               return Err(PeerHandleError{ no_connection_possible: true }.into());
+                               return Err(PeerHandleError { }.into());
                        },
                        wire::Message::Unknown(type_id) => {
                                log_trace!(self.logger, "Received unknown odd message of type {}, ignoring", type_id);
@@ -1465,10 +1556,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
-                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                       if !peer.handshake_complete() ||
                                                        !peer.should_forward_channel_announcement(msg.contents.short_channel_id) {
                                                continue
                                        }
+                                       debug_assert!(peer.their_node_id.is_some());
+                                       debug_assert!(peer.channel_encryptor.is_ready_for_encryption());
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
@@ -1490,10 +1583,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
-                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                       if !peer.handshake_complete() ||
                                                        !peer.should_forward_node_announcement(msg.contents.node_id) {
                                                continue
                                        }
+                                       debug_assert!(peer.their_node_id.is_some());
+                                       debug_assert!(peer.channel_encryptor.is_ready_for_encryption());
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
@@ -1515,10 +1610,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
                                for (_, peer_mutex) in peers.iter() {
                                        let mut peer = peer_mutex.lock().unwrap();
-                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                       if !peer.handshake_complete() ||
                                                        !peer.should_forward_channel_announcement(msg.contents.short_channel_id)  {
                                                continue
                                        }
+                                       debug_assert!(peer.their_node_id.is_some());
+                                       debug_assert!(peer.channel_encryptor.is_ready_for_encryption());
                                        if peer.buffer_full_drop_gossip_broadcast() {
                                                log_gossip!(self.logger, "Skipping broadcast message to {:?} as its outbound buffer is full", peer.their_node_id);
                                                continue;
@@ -1572,6 +1669,9 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        }
                }
 
+               self.update_gossip_backlogged();
+               let flush_read_disabled = self.gossip_processing_backlog_lifted.swap(false, Ordering::Relaxed);
+
                let mut peers_to_disconnect = HashMap::new();
                let mut events_generated = self.message_handler.chan_handler.get_and_clear_pending_msg_events();
                events_generated.append(&mut self.message_handler.route_handler.get_and_clear_pending_msg_events());
@@ -1595,7 +1695,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                        Some(descriptor) => match peers.get(&descriptor) {
                                                                Some(peer_mutex) => {
                                                                        let peer_lock = peer_mutex.lock().unwrap();
-                                                                       if peer_lock.their_features.is_none() {
+                                                                       if !peer_lock.handshake_complete() {
                                                                                continue;
                                                                        }
                                                                        peer_lock
@@ -1716,10 +1816,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                                self.forward_broadcast_msg(peers, &wire::Message::ChannelAnnouncement(msg), None),
                                                        _ => {},
                                                }
-                                               match self.message_handler.route_handler.handle_channel_update(&update_msg) {
-                                                       Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
-                                                               self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(update_msg), None),
-                                                       _ => {},
+                                               if let Some(msg) = update_msg {
+                                                       match self.message_handler.route_handler.handle_channel_update(&msg) {
+                                                               Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
+                                                                       self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(msg), None),
+                                                               _ => {},
+                                                       }
                                                }
                                        },
                                        MessageSendEvent::BroadcastChannelUpdate { msg } => {
@@ -1730,6 +1832,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                                        _ => {},
                                                }
                                        },
+                                       MessageSendEvent::BroadcastNodeAnnouncement { msg } => {
+                                               log_debug!(self.logger, "Handling BroadcastNodeAnnouncement event in peer_handler for node {}", msg.contents.node_id);
+                                               match self.message_handler.route_handler.handle_node_announcement(&msg) {
+                                                       Ok(_) | Err(LightningError { action: msgs::ErrorAction::IgnoreDuplicateGossip, .. }) =>
+                                                               self.forward_broadcast_msg(peers, &wire::Message::NodeAnnouncement(msg), None),
+                                                       _ => {},
+                                               }
+                                       },
                                        MessageSendEvent::SendChannelUpdate { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendChannelUpdate event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id), msg.contents.short_channel_id);
@@ -1791,7 +1901,9 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        }
 
                        for (descriptor, peer_mutex) in peers.iter() {
-                               self.do_attempt_write_data(&mut (*descriptor).clone(), &mut *peer_mutex.lock().unwrap());
+                               let mut peer = peer_mutex.lock().unwrap();
+                               if flush_read_disabled { peer.received_channel_announce_since_backlogged = false; }
+                               self.do_attempt_write_data(&mut (*descriptor).clone(), &mut *peer, flush_read_disabled);
                        }
                }
                if !peers_to_disconnect.is_empty() {
@@ -1803,24 +1915,21 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                // thread can be holding the peer lock if we have the global write
                                // lock).
 
-                               if let Some(mut descriptor) = self.node_id_to_descriptor.lock().unwrap().remove(&node_id) {
+                               let descriptor_opt = self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
+                               if let Some(mut descriptor) = descriptor_opt {
                                        if let Some(peer_mutex) = peers.remove(&descriptor) {
+                                               let mut peer = peer_mutex.lock().unwrap();
                                                if let Some(msg) = msg {
                                                        log_trace!(self.logger, "Handling DisconnectPeer HandleError event in peer_handler for node {} with message {}",
                                                                        log_pubkey!(node_id),
                                                                        msg.data);
-                                                       let mut peer = peer_mutex.lock().unwrap();
                                                        self.enqueue_message(&mut *peer, &msg);
                                                        // This isn't guaranteed to work, but if there is enough free
                                                        // room in the send buffer, put the error message there...
-                                                       self.do_attempt_write_data(&mut descriptor, &mut *peer);
-                                               } else {
-                                                       log_trace!(self.logger, "Handling DisconnectPeer HandleError event in peer_handler for node {} with no message", log_pubkey!(node_id));
+                                                       self.do_attempt_write_data(&mut descriptor, &mut *peer, false);
                                                }
-                                       }
-                                       descriptor.disconnect_socket();
-                                       self.message_handler.chan_handler.peer_disconnected(&node_id, false);
-                                       self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
+                                               self.do_disconnect(descriptor, &*peer, "DisconnectPeer HandleError");
+                                       } else { debug_assert!(false, "Missing connection for peer"); }
                                }
                        }
                }
@@ -1828,10 +1937,26 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
        /// Indicates that the given socket descriptor's connection is now closed.
        pub fn socket_disconnected(&self, descriptor: &Descriptor) {
-               self.disconnect_event_internal(descriptor, false);
+               self.disconnect_event_internal(descriptor);
        }
 
-       fn disconnect_event_internal(&self, descriptor: &Descriptor, no_connection_possible: bool) {
+       fn do_disconnect(&self, mut descriptor: Descriptor, peer: &Peer, reason: &'static str) {
+               if !peer.handshake_complete() {
+                       log_trace!(self.logger, "Disconnecting peer which hasn't completed handshake due to {}", reason);
+                       descriptor.disconnect_socket();
+                       return;
+               }
+
+               debug_assert!(peer.their_node_id.is_some());
+               if let Some((node_id, _)) = peer.their_node_id {
+                       log_trace!(self.logger, "Disconnecting peer with id {} due to {}", node_id, reason);
+                       self.message_handler.chan_handler.peer_disconnected(&node_id);
+                       self.message_handler.onion_message_handler.peer_disconnected(&node_id);
+               }
+               descriptor.disconnect_socket();
+       }
+
+       fn disconnect_event_internal(&self, descriptor: &Descriptor) {
                let mut peers = self.peers.write().unwrap();
                let peer_option = peers.remove(descriptor);
                match peer_option {
@@ -1843,12 +1968,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                        Some(peer_lock) => {
                                let peer = peer_lock.lock().unwrap();
                                if let Some((node_id, _)) = peer.their_node_id {
-                                       log_trace!(self.logger,
-                                               "Handling disconnection of peer {}, with {}future connection to the peer possible.",
-                                               log_pubkey!(node_id), if no_connection_possible { "no " } else { "" });
-                                       self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
-                                       self.message_handler.chan_handler.peer_disconnected(&node_id, no_connection_possible);
-                                       self.message_handler.onion_message_handler.peer_disconnected(&node_id, no_connection_possible);
+                                       log_trace!(self.logger, "Handling disconnection of peer {}", log_pubkey!(node_id));
+                                       let removed = self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
+                                       debug_assert!(removed.is_some(), "descriptor maps should be consistent");
+                                       if !peer.handshake_complete() { return; }
+                                       self.message_handler.chan_handler.peer_disconnected(&node_id);
+                                       self.message_handler.onion_message_handler.peer_disconnected(&node_id);
                                }
                        }
                };
@@ -1856,21 +1981,17 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
        /// Disconnect a peer given its node id.
        ///
-       /// Set `no_connection_possible` to true to prevent any further connection with this peer,
-       /// force-closing any channels we have with it.
-       ///
        /// If a peer is connected, this will call [`disconnect_socket`] on the descriptor for the
        /// peer. Thus, be very careful about reentrancy issues.
        ///
        /// [`disconnect_socket`]: SocketDescriptor::disconnect_socket
-       pub fn disconnect_by_node_id(&self, node_id: PublicKey, no_connection_possible: bool) {
+       pub fn disconnect_by_node_id(&self, node_id: PublicKey) {
                let mut peers_lock = self.peers.write().unwrap();
-               if let Some(mut descriptor) = self.node_id_to_descriptor.lock().unwrap().remove(&node_id) {
-                       log_trace!(self.logger, "Disconnecting peer with id {} due to client request", node_id);
-                       peers_lock.remove(&descriptor);
-                       self.message_handler.chan_handler.peer_disconnected(&node_id, no_connection_possible);
-                       self.message_handler.onion_message_handler.peer_disconnected(&node_id, no_connection_possible);
-                       descriptor.disconnect_socket();
+               if let Some(descriptor) = self.node_id_to_descriptor.lock().unwrap().remove(&node_id) {
+                       let peer_opt = peers_lock.remove(&descriptor);
+                       if let Some(peer_mutex) = peer_opt {
+                               self.do_disconnect(descriptor, &*peer_mutex.lock().unwrap(), "client request");
+                       } else { debug_assert!(false, "node_id_to_descriptor thought we had a peer"); }
                }
        }
 
@@ -1881,13 +2002,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                let mut peers_lock = self.peers.write().unwrap();
                self.node_id_to_descriptor.lock().unwrap().clear();
                let peers = &mut *peers_lock;
-               for (mut descriptor, peer) in peers.drain() {
-                       if let Some((node_id, _)) = peer.lock().unwrap().their_node_id {
-                               log_trace!(self.logger, "Disconnecting peer with id {} due to client request to disconnect all peers", node_id);
-                               self.message_handler.chan_handler.peer_disconnected(&node_id, false);
-                               self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
-                       }
-                       descriptor.disconnect_socket();
+               for (descriptor, peer_mutex) in peers.drain() {
+                       self.do_disconnect(descriptor, &*peer_mutex.lock().unwrap(), "client request to disconnect all peers");
                }
        }
 
@@ -1921,9 +2037,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                {
                        let peers_lock = self.peers.read().unwrap();
 
+                       self.update_gossip_backlogged();
+                       let flush_read_disabled = self.gossip_processing_backlog_lifted.swap(false, Ordering::Relaxed);
+
                        for (descriptor, peer_mutex) in peers_lock.iter() {
                                let mut peer = peer_mutex.lock().unwrap();
-                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_node_id.is_none() {
+                               if flush_read_disabled { peer.received_channel_announce_since_backlogged = false; }
+
+                               if !peer.handshake_complete() {
                                        // The peer needs to complete its handshake before we can exchange messages. We
                                        // give peers one timer tick to complete handshake, reusing
                                        // `awaiting_pong_timer_tick_intervals` to track number of timer ticks taken
@@ -1935,56 +2056,56 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
                                        }
                                        continue;
                                }
+                               debug_assert!(peer.channel_encryptor.is_ready_for_encryption());
+                               debug_assert!(peer.their_node_id.is_some());
 
-                               if peer.awaiting_pong_timer_tick_intervals == -1 {
-                                       // Magic value set in `maybe_send_extra_ping`.
-                                       peer.awaiting_pong_timer_tick_intervals = 1;
+                               loop { // Used as a `goto` to skip writing a Ping message.
+                                       if peer.awaiting_pong_timer_tick_intervals == -1 {
+                                               // Magic value set in `maybe_send_extra_ping`.
+                                               peer.awaiting_pong_timer_tick_intervals = 1;
+                                               peer.received_message_since_timer_tick = false;
+                                               break;
+                                       }
+
+                                       if (peer.awaiting_pong_timer_tick_intervals > 0 && !peer.received_message_since_timer_tick)
+                                               || peer.awaiting_pong_timer_tick_intervals as u64 >
+                                                       MAX_BUFFER_DRAIN_TICK_INTERVALS_PER_PEER as u64 * peers_lock.len() as u64
+                                       {
+                                               descriptors_needing_disconnect.push(descriptor.clone());
+                                               break;
+                                       }
                                        peer.received_message_since_timer_tick = false;
-                                       continue;
-                               }
 
-                               if (peer.awaiting_pong_timer_tick_intervals > 0 && !peer.received_message_since_timer_tick)
-                                       || peer.awaiting_pong_timer_tick_intervals as u64 >
-                                               MAX_BUFFER_DRAIN_TICK_INTERVALS_PER_PEER as u64 * peers_lock.len() as u64
-                               {
-                                       descriptors_needing_disconnect.push(descriptor.clone());
-                                       continue;
-                               }
-                               peer.received_message_since_timer_tick = false;
+                                       if peer.awaiting_pong_timer_tick_intervals > 0 {
+                                               peer.awaiting_pong_timer_tick_intervals += 1;
+                                               break;
+                                       }
 
-                               if peer.awaiting_pong_timer_tick_intervals > 0 {
-                                       peer.awaiting_pong_timer_tick_intervals += 1;
-                                       continue;
+                                       peer.awaiting_pong_timer_tick_intervals = 1;
+                                       let ping = msgs::Ping {
+                                               ponglen: 0,
+                                               byteslen: 64,
+                                       };
+                                       self.enqueue_message(&mut *peer, &ping);
+                                       break;
                                }
-
-                               peer.awaiting_pong_timer_tick_intervals = 1;
-                               let ping = msgs::Ping {
-                                       ponglen: 0,
-                                       byteslen: 64,
-                               };
-                               self.enqueue_message(&mut *peer, &ping);
-                               self.do_attempt_write_data(&mut (descriptor.clone()), &mut *peer);
+                               self.do_attempt_write_data(&mut (descriptor.clone()), &mut *peer, flush_read_disabled);
                        }
                }
 
                if !descriptors_needing_disconnect.is_empty() {
                        {
                                let mut peers_lock = self.peers.write().unwrap();
-                               for descriptor in descriptors_needing_disconnect.iter() {
-                                       if let Some(peer) = peers_lock.remove(descriptor) {
-                                               if let Some((node_id, _)) = peer.lock().unwrap().their_node_id {
-                                                       log_trace!(self.logger, "Disconnecting peer with id {} due to ping timeout", node_id);
+                               for descriptor in descriptors_needing_disconnect {
+                                       if let Some(peer_mutex) = peers_lock.remove(&descriptor) {
+                                               let peer = peer_mutex.lock().unwrap();
+                                               if let Some((node_id, _)) = peer.their_node_id {
                                                        self.node_id_to_descriptor.lock().unwrap().remove(&node_id);
-                                                       self.message_handler.chan_handler.peer_disconnected(&node_id, false);
-                                                       self.message_handler.onion_message_handler.peer_disconnected(&node_id, false);
                                                }
+                                               self.do_disconnect(descriptor, &*peer, "ping timeout");
                                        }
                                }
                        }
-
-                       for mut descriptor in descriptors_needing_disconnect.drain(..) {
-                               descriptor.disconnect_socket();
-                       }
                }
        }
 
@@ -2072,6 +2193,7 @@ fn is_gossip_msg(type_id: u16) -> bool {
 #[cfg(test)]
 mod tests {
        use crate::chain::keysinterface::{NodeSigner, Recipient};
+       use crate::ln::peer_channel_encryptor::PeerChannelEncryptor;
        use crate::ln::peer_handler::{PeerManager, MessageHandler, SocketDescriptor, IgnoringMessageHandler, filter_addresses};
        use crate::ln::{msgs, wire};
        use crate::ln::msgs::NetAddress;
@@ -2082,12 +2204,13 @@ mod tests {
 
        use crate::prelude::*;
        use crate::sync::{Arc, Mutex};
-       use core::sync::atomic::Ordering;
+       use core::sync::atomic::{AtomicBool, Ordering};
 
        #[derive(Clone)]
        struct FileDescriptor {
                fd: u16,
                outbound_data: Arc<Mutex<Vec<u8>>>,
+               disconnect: Arc<AtomicBool>,
        }
        impl PartialEq for FileDescriptor {
                fn eq(&self, other: &Self) -> bool {
@@ -2107,7 +2230,7 @@ mod tests {
                        data.len()
                }
 
-               fn disconnect_socket(&mut self) {}
+               fn disconnect_socket(&mut self) { self.disconnect.store(true, Ordering::Release); }
        }
 
        struct PeerManagerCfg {
@@ -2147,11 +2270,20 @@ mod tests {
        }
 
        fn establish_connection<'a>(peer_a: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler, &'a test_utils::TestRoutingMessageHandler, IgnoringMessageHandler, &'a test_utils::TestLogger, IgnoringMessageHandler, &'a test_utils::TestNodeSigner>, peer_b: &PeerManager<FileDescriptor, &'a test_utils::TestChannelMessageHandler, &'a test_utils::TestRoutingMessageHandler, IgnoringMessageHandler, &'a test_utils::TestLogger, IgnoringMessageHandler, &'a test_utils::TestNodeSigner>) -> (FileDescriptor, FileDescriptor) {
-               let a_id = peer_a.node_signer.get_node_id(Recipient::Node).unwrap();
-               let mut fd_a = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
-               let mut fd_b = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
-               let initial_data = peer_b.new_outbound_connection(a_id, fd_b.clone(), None).unwrap();
-               peer_a.new_inbound_connection(fd_a.clone(), None).unwrap();
+               let id_a = peer_a.node_signer.get_node_id(Recipient::Node).unwrap();
+               let mut fd_a = FileDescriptor {
+                       fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                       disconnect: Arc::new(AtomicBool::new(false)),
+               };
+               let addr_a = NetAddress::IPv4{addr: [127, 0, 0, 1], port: 1000};
+               let id_b = peer_b.node_signer.get_node_id(Recipient::Node).unwrap();
+               let mut fd_b = FileDescriptor {
+                       fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                       disconnect: Arc::new(AtomicBool::new(false)),
+               };
+               let addr_b = NetAddress::IPv4{addr: [127, 0, 0, 1], port: 1001};
+               let initial_data = peer_b.new_outbound_connection(id_a, fd_b.clone(), Some(addr_a.clone())).unwrap();
+               peer_a.new_inbound_connection(fd_a.clone(), Some(addr_b.clone())).unwrap();
                assert_eq!(peer_a.read_event(&mut fd_a, &initial_data).unwrap(), false);
                peer_a.process_events();
 
@@ -2166,27 +2298,106 @@ mod tests {
                let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
                assert_eq!(peer_b.read_event(&mut fd_b, &a_data).unwrap(), false);
 
+               assert!(peer_a.get_peer_node_ids().contains(&(id_b, Some(addr_b))));
+               assert!(peer_b.get_peer_node_ids().contains(&(id_a, Some(addr_a))));
+
                (fd_a.clone(), fd_b.clone())
        }
 
+       #[test]
+       #[cfg(feature = "std")]
+       fn fuzz_threaded_connections() {
+               // Spawn two threads which repeatedly connect two peers together, leading to "got second
+               // connection with peer" disconnections and rapid reconnect. This previously found an issue
+               // with our internal map consistency, and is a generally good smoke test of disconnection.
+               let cfgs = Arc::new(create_peermgr_cfgs(2));
+               // Until we have std::thread::scoped we have to unsafe { turn off the borrow checker }.
+               let peers = Arc::new(create_network(2, unsafe { &*(&*cfgs as *const _) as &'static _ }));
+
+               let start_time = std::time::Instant::now();
+               macro_rules! spawn_thread { ($id: expr) => { {
+                       let peers = Arc::clone(&peers);
+                       let cfgs = Arc::clone(&cfgs);
+                       std::thread::spawn(move || {
+                               let mut ctr = 0;
+                               while start_time.elapsed() < std::time::Duration::from_secs(1) {
+                                       let id_a = peers[0].node_signer.get_node_id(Recipient::Node).unwrap();
+                                       let mut fd_a = FileDescriptor {
+                                               fd: $id  + ctr * 3, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                                               disconnect: Arc::new(AtomicBool::new(false)),
+                                       };
+                                       let addr_a = NetAddress::IPv4{addr: [127, 0, 0, 1], port: 1000};
+                                       let mut fd_b = FileDescriptor {
+                                               fd: $id + ctr * 3, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                                               disconnect: Arc::new(AtomicBool::new(false)),
+                                       };
+                                       let addr_b = NetAddress::IPv4{addr: [127, 0, 0, 1], port: 1001};
+                                       let initial_data = peers[1].new_outbound_connection(id_a, fd_b.clone(), Some(addr_a.clone())).unwrap();
+                                       peers[0].new_inbound_connection(fd_a.clone(), Some(addr_b.clone())).unwrap();
+                                       if peers[0].read_event(&mut fd_a, &initial_data).is_err() { break; }
+
+                                       while start_time.elapsed() < std::time::Duration::from_secs(1) {
+                                               peers[0].process_events();
+                                               if fd_a.disconnect.load(Ordering::Acquire) { break; }
+                                               let a_data = fd_a.outbound_data.lock().unwrap().split_off(0);
+                                               if peers[1].read_event(&mut fd_b, &a_data).is_err() { break; }
+
+                                               peers[1].process_events();
+                                               if fd_b.disconnect.load(Ordering::Acquire) { break; }
+                                               let b_data = fd_b.outbound_data.lock().unwrap().split_off(0);
+                                               if peers[0].read_event(&mut fd_a, &b_data).is_err() { break; }
+
+                                               cfgs[0].chan_handler.pending_events.lock().unwrap()
+                                                       .push(crate::util::events::MessageSendEvent::SendShutdown {
+                                                               node_id: peers[1].node_signer.get_node_id(Recipient::Node).unwrap(),
+                                                               msg: msgs::Shutdown {
+                                                                       channel_id: [0; 32],
+                                                                       scriptpubkey: bitcoin::Script::new(),
+                                                               },
+                                                       });
+                                               cfgs[1].chan_handler.pending_events.lock().unwrap()
+                                                       .push(crate::util::events::MessageSendEvent::SendShutdown {
+                                                               node_id: peers[0].node_signer.get_node_id(Recipient::Node).unwrap(),
+                                                               msg: msgs::Shutdown {
+                                                                       channel_id: [0; 32],
+                                                                       scriptpubkey: bitcoin::Script::new(),
+                                                               },
+                                                       });
+
+                                               if ctr % 2 == 0 {
+                                                       peers[0].timer_tick_occurred();
+                                                       peers[1].timer_tick_occurred();
+                                               }
+                                       }
+
+                                       peers[0].socket_disconnected(&fd_a);
+                                       peers[1].socket_disconnected(&fd_b);
+                                       ctr += 1;
+                                       std::thread::sleep(std::time::Duration::from_micros(1));
+                               }
+                       })
+               } } }
+               let thrd_a = spawn_thread!(1);
+               let thrd_b = spawn_thread!(2);
+
+               thrd_a.join().unwrap();
+               thrd_b.join().unwrap();
+       }
+
        #[test]
        fn test_disconnect_peer() {
                // Simple test which builds a network of PeerManager, connects and brings them to NoiseState::Finished and
                // push a DisconnectPeer event to remove the node flagged by id
                let cfgs = create_peermgr_cfgs(2);
-               let chan_handler = test_utils::TestChannelMessageHandler::new();
-               let mut peers = create_network(2, &cfgs);
+               let peers = create_network(2, &cfgs);
                establish_connection(&peers[0], &peers[1]);
                assert_eq!(peers[0].peers.read().unwrap().len(), 1);
 
                let their_id = peers[1].node_signer.get_node_id(Recipient::Node).unwrap();
-
-               chan_handler.pending_events.lock().unwrap().push(events::MessageSendEvent::HandleError {
+               cfgs[0].chan_handler.pending_events.lock().unwrap().push(events::MessageSendEvent::HandleError {
                        node_id: their_id,
                        action: msgs::ErrorAction::DisconnectPeer { msg: None },
                });
-               assert_eq!(chan_handler.pending_events.lock().unwrap().len(), 1);
-               peers[0].message_handler.chan_handler = &chan_handler;
 
                peers[0].process_events();
                assert_eq!(peers[0].peers.read().unwrap().len(), 0);
@@ -2220,6 +2431,38 @@ mod tests {
                assert_eq!(peers[1].read_event(&mut fd_b, &a_data).unwrap(), false);
        }
 
+       #[test]
+       fn test_non_init_first_msg() {
+               // Simple test of the first message received over a connection being something other than
+               // Init. This results in an immediate disconnection, which previously included a spurious
+               // peer_disconnected event handed to event handlers (which would panic in
+               // `TestChannelMessageHandler` here).
+               let cfgs = create_peermgr_cfgs(2);
+               let peers = create_network(2, &cfgs);
+
+               let mut fd_dup = FileDescriptor {
+                       fd: 3, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                       disconnect: Arc::new(AtomicBool::new(false)),
+               };
+               let addr_dup = NetAddress::IPv4{addr: [127, 0, 0, 1], port: 1003};
+               let id_a = cfgs[0].node_signer.get_node_id(Recipient::Node).unwrap();
+               peers[0].new_inbound_connection(fd_dup.clone(), Some(addr_dup.clone())).unwrap();
+
+               let mut dup_encryptor = PeerChannelEncryptor::new_outbound(id_a, SecretKey::from_slice(&[42; 32]).unwrap());
+               let initial_data = dup_encryptor.get_act_one(&peers[1].secp_ctx);
+               assert_eq!(peers[0].read_event(&mut fd_dup, &initial_data).unwrap(), false);
+               peers[0].process_events();
+
+               let a_data = fd_dup.outbound_data.lock().unwrap().split_off(0);
+               let (act_three, _) =
+                       dup_encryptor.process_act_two(&a_data[..], &&cfgs[1].node_signer).unwrap();
+               assert_eq!(peers[0].read_event(&mut fd_dup, &act_three).unwrap(), false);
+
+               let not_init_msg = msgs::Ping { ponglen: 4, byteslen: 0 };
+               let msg_bytes = dup_encryptor.encrypt_message(&not_init_msg);
+               assert!(peers[0].read_event(&mut fd_dup, &msg_bytes).is_err());
+       }
+
        #[test]
        fn test_disconnect_all_peer() {
                // Simple test which builds a network of PeerManager, connects and brings them to NoiseState::Finished and
@@ -2304,8 +2547,14 @@ mod tests {
                let peers = create_network(2, &cfgs);
 
                let a_id = peers[0].node_signer.get_node_id(Recipient::Node).unwrap();
-               let mut fd_a = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
-               let mut fd_b = FileDescriptor { fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())) };
+               let mut fd_a = FileDescriptor {
+                       fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                       disconnect: Arc::new(AtomicBool::new(false)),
+               };
+               let mut fd_b = FileDescriptor {
+                       fd: 1, outbound_data: Arc::new(Mutex::new(Vec::new())),
+                       disconnect: Arc::new(AtomicBool::new(false)),
+               };
                let initial_data = peers[1].new_outbound_connection(a_id, fd_b.clone(), None).unwrap();
                peers[0].new_inbound_connection(fd_a.clone(), None).unwrap();