Merge pull request #948 from TheBlueMatt/2021-06-p2p-fixes
authorMatt Corallo <649246+TheBlueMatt@users.noreply.github.com>
Mon, 21 Jun 2021 20:23:39 +0000 (20:23 +0000)
committerGitHub <noreply@github.com>
Mon, 21 Jun 2021 20:23:39 +0000 (20:23 +0000)
Clean up message forwarding and relay gossip messages

lightning/src/ln/peer_handler.rs

index 6e05b5498cf284391db623152242a571c57aa346..2eb9b2e78f06aba02f0c8cebff65871b3ff94f1d 100644 (file)
@@ -233,6 +233,15 @@ enum InitSyncTracker{
        NodesSyncing(PublicKey),
 }
 
+/// When the outbound buffer has this many messages, we'll stop reading bytes from the peer until
+/// we have fewer than this many messages in the outbound buffer again.
+/// We also use this as the target number of outbound gossip messages to keep in the write buffer,
+/// refilled as we send bytes.
+const OUTBOUND_BUFFER_LIMIT_READ_PAUSE: usize = 10;
+/// When the outbound buffer has this many messages, we'll simply skip relaying gossip messages to
+/// the peer.
+const OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP: usize = 20;
+
 struct Peer {
        channel_encryptor: PeerChannelEncryptor,
        their_node_id: Option<PublicKey>,
@@ -278,9 +287,6 @@ impl Peer {
 
 struct PeerHolder<Descriptor: SocketDescriptor> {
        peers: HashMap<Descriptor, Peer>,
-       /// Added to by do_read_event for cases where we pushed a message onto the send buffer but
-       /// didn't call do_attempt_write_data to avoid reentrancy. Cleared in process_events()
-       peers_needing_send: HashSet<Descriptor>,
        /// Only add to this set when noise completes:
        node_id_to_descriptor: HashMap<PublicKey, Descriptor>,
 }
@@ -411,7 +417,6 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                        message_handler,
                        peers: Mutex::new(PeerHolder {
                                peers: HashMap::new(),
-                               peers_needing_send: HashSet::new(),
                                node_id_to_descriptor: HashMap::new()
                        }),
                        our_node_secret,
@@ -531,13 +536,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                }
                        }
                }
-               const MSG_BUFF_SIZE: usize = 10;
                while !peer.awaiting_write_event {
-                       if peer.pending_outbound_buffer.len() < MSG_BUFF_SIZE {
+                       if peer.pending_outbound_buffer.len() < OUTBOUND_BUFFER_LIMIT_READ_PAUSE {
                                match peer.sync_status {
                                        InitSyncTracker::NoSyncRequested => {},
                                        InitSyncTracker::ChannelsSyncing(c) if c < 0xffff_ffff_ffff_ffff => {
-                                               let steps = ((MSG_BUFF_SIZE - peer.pending_outbound_buffer.len() + 2) / 3) as u8;
+                                               let steps = ((OUTBOUND_BUFFER_LIMIT_READ_PAUSE - peer.pending_outbound_buffer.len() + 2) / 3) as u8;
                                                let all_messages = self.message_handler.route_handler.get_next_channel_announcements(c, steps);
                                                for &(ref announce, ref update_a_option, ref update_b_option) in all_messages.iter() {
                                                        encode_and_send_msg!(announce);
@@ -554,7 +558,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                }
                                        },
                                        InitSyncTracker::ChannelsSyncing(c) if c == 0xffff_ffff_ffff_ffff => {
-                                               let steps = (MSG_BUFF_SIZE - peer.pending_outbound_buffer.len()) as u8;
+                                               let steps = (OUTBOUND_BUFFER_LIMIT_READ_PAUSE - peer.pending_outbound_buffer.len()) as u8;
                                                let all_messages = self.message_handler.route_handler.get_next_node_announcements(None, steps);
                                                for msg in all_messages.iter() {
                                                        encode_and_send_msg!(msg);
@@ -566,7 +570,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                        },
                                        InitSyncTracker::ChannelsSyncing(_) => unreachable!(),
                                        InitSyncTracker::NodesSyncing(key) => {
-                                               let steps = (MSG_BUFF_SIZE - peer.pending_outbound_buffer.len()) as u8;
+                                               let steps = (OUTBOUND_BUFFER_LIMIT_READ_PAUSE - peer.pending_outbound_buffer.len()) as u8;
                                                let all_messages = self.message_handler.route_handler.get_next_node_announcements(Some(&key), steps);
                                                for msg in all_messages.iter() {
                                                        encode_and_send_msg!(msg);
@@ -585,7 +589,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                        Some(buff) => buff,
                                };
 
-                               let should_be_reading = peer.pending_outbound_buffer.len() < MSG_BUFF_SIZE;
+                               let should_be_reading = peer.pending_outbound_buffer.len() < OUTBOUND_BUFFER_LIMIT_READ_PAUSE;
                                let pending = &next_buff[peer.pending_outbound_buffer_first_msg_offset..];
                                let data_sent = descriptor.send_data(pending, should_be_reading);
                                peer.pending_outbound_buffer_first_msg_offset += data_sent;
@@ -644,20 +648,21 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
        }
 
        /// Append a message to a peer's pending outbound/write buffer, and update the map of peers needing sends accordingly.
-       fn enqueue_message<M: Encode + Writeable>(&self, peers_needing_send: &mut HashSet<Descriptor>, peer: &mut Peer, descriptor: Descriptor, message: &M) {
+       fn enqueue_message<M: Encode + Writeable>(&self, peer: &mut Peer, message: &M) {
                let mut buffer = VecWriter(Vec::new());
                wire::write(message, &mut buffer).unwrap(); // crash if the write failed
                let encoded_message = buffer.0;
 
                log_trace!(self.logger, "Enqueueing message of type {} to {}", message.type_id(), log_pubkey!(peer.their_node_id.unwrap()));
                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_message[..]));
-               peers_needing_send.insert(descriptor);
        }
 
        fn do_read_event(&self, peer_descriptor: &mut Descriptor, data: &[u8]) -> Result<bool, PeerHandleError> {
                let pause_read = {
                        let mut peers_lock = self.peers.lock().unwrap();
                        let peers = &mut *peers_lock;
+                       let mut msgs_to_forward = Vec::new();
+                       let mut peer_node_id = None;
                        let pause_read = match peers.peers.get_mut(peer_descriptor) {
                                None => panic!("Descriptor for read_event is not already known to PeerManager"),
                                Some(peer) => {
@@ -693,7 +698,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                                                },
                                                                                                msgs::ErrorAction::SendErrorMessage { msg } => {
                                                                                                        log_trace!(self.logger, "Got Err handling message, sending Error message because {}", e.err);
-                                                                                                       self.enqueue_message(&mut peers.peers_needing_send, peer, peer_descriptor.clone(), &msg);
+                                                                                                       self.enqueue_message(peer, &msg);
                                                                                                        continue;
                                                                                                },
                                                                                        }
@@ -735,7 +740,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                        insert_node_id!();
                                                                        let features = InitFeatures::known();
                                                                        let resp = msgs::Init { features };
-                                                                       self.enqueue_message(&mut peers.peers_needing_send, peer, peer_descriptor.clone(), &resp);
+                                                                       self.enqueue_message(peer, &resp);
                                                                },
                                                                NextNoiseStep::ActThree => {
                                                                        let their_node_id = try_potential_handleerror!(peer.channel_encryptor.process_act_three(&peer.pending_read_buffer[..]));
@@ -745,7 +750,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                        insert_node_id!();
                                                                        let features = InitFeatures::known();
                                                                        let resp = msgs::Init { features };
-                                                                       self.enqueue_message(&mut peers.peers_needing_send, peer, peer_descriptor.clone(), &resp);
+                                                                       self.enqueue_message(peer, &resp);
                                                                },
                                                                NextNoiseStep::NoiseComplete => {
                                                                        if peer.pending_read_is_header {
@@ -793,13 +798,18 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                                        }
                                                                                };
 
-                                                                               if let Err(handling_error) = self.handle_message(&mut peers.peers_needing_send, peer, peer_descriptor.clone(), message){
-                                                                                       match handling_error {
+                                                                               match self.handle_message(peer, message) {
+                                                                                       Err(handling_error) => match handling_error {
                                                                                                MessageHandlingError::PeerHandleError(e) => { return Err(e) },
                                                                                                MessageHandlingError::LightningError(e) => {
                                                                                                        try_potential_handleerror!(Err(e));
                                                                                                },
-                                                                                       }
+                                                                                       },
+                                                                                       Ok(Some(msg)) => {
+                                                                                               peer_node_id = Some(peer.their_node_id.expect("After noise is complete, their_node_id is always set"));
+                                                                                               msgs_to_forward.push(msg);
+                                                                                       },
+                                                                                       Ok(None) => {},
                                                                                }
                                                                        }
                                                                }
@@ -807,12 +817,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                }
                                        }
 
-                                       self.do_attempt_write_data(peer_descriptor, peer);
-
-                                       peer.pending_outbound_buffer.len() > 10 // pause_read
+                                       peer.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_READ_PAUSE // pause_read
                                }
                        };
 
+                       for msg in msgs_to_forward.drain(..) {
+                               self.forward_broadcast_msg(peers, &msg, peer_node_id.as_ref());
+                       }
+
                        pause_read
                };
 
@@ -820,7 +832,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
        }
 
        /// Process an incoming message and return a decision (ok, lightning error, peer handling error) regarding the next action with the peer
-       fn handle_message(&self, peers_needing_send: &mut HashSet<Descriptor>, peer: &mut Peer, peer_descriptor: Descriptor, message: wire::Message) -> Result<(), MessageHandlingError> {
+       /// Returns the message back if it needs to be broadcasted to all other peers.
+       fn handle_message(&self, peer: &mut Peer, message: wire::Message) -> Result<Option<wire::Message>, MessageHandlingError> {
                log_trace!(self.logger, "Received message of type {} from {}", message.type_id(), log_pubkey!(peer.their_node_id.unwrap()));
 
                // Need an Init as first message
@@ -830,6 +843,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                        return Err(PeerHandleError{ no_connection_possible: false }.into());
                }
 
+               let mut should_forward = None;
+
                match message {
                        // Setup and Control messages:
                        wire::Message::Init(msg) => {
@@ -853,7 +868,6 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
 
                                if msg.features.initial_routing_sync() {
                                        peer.sync_status = InitSyncTracker::ChannelsSyncing(0);
-                                       peers_needing_send.insert(peer_descriptor.clone());
                                }
                                if !msg.features.supports_static_remote_key() {
                                        log_debug!(self.logger, "Peer {} does not support static remote key, disconnecting with no_connection_possible", log_pubkey!(peer.their_node_id.unwrap()));
@@ -888,7 +902,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                        wire::Message::Ping(msg) => {
                                if msg.ponglen < 65532 {
                                        let resp = msgs::Pong { byteslen: msg.ponglen };
-                                       self.enqueue_message(peers_needing_send, peer, peer_descriptor.clone(), &resp);
+                                       self.enqueue_message(peer, &resp);
                                }
                        },
                        wire::Message::Pong(_msg) => {
@@ -952,34 +966,22 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                self.message_handler.chan_handler.handle_announcement_signatures(&peer.their_node_id.unwrap(), &msg);
                        },
                        wire::Message::ChannelAnnouncement(msg) => {
-                               let should_forward = match self.message_handler.route_handler.handle_channel_announcement(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               };
-
-                               if should_forward {
-                                       // TODO: forward msg along to all our other peers!
+                               if self.message_handler.route_handler.handle_channel_announcement(&msg)
+                                               .map_err(|e| -> MessageHandlingError { e.into() })? {
+                                       should_forward = Some(wire::Message::ChannelAnnouncement(msg));
                                }
                        },
                        wire::Message::NodeAnnouncement(msg) => {
-                               let should_forward = match self.message_handler.route_handler.handle_node_announcement(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               };
-
-                               if should_forward {
-                                       // TODO: forward msg along to all our other peers!
+                               if self.message_handler.route_handler.handle_node_announcement(&msg)
+                                               .map_err(|e| -> MessageHandlingError { e.into() })? {
+                                       should_forward = Some(wire::Message::NodeAnnouncement(msg));
                                }
                        },
                        wire::Message::ChannelUpdate(msg) => {
                                self.message_handler.chan_handler.handle_channel_update(&peer.their_node_id.unwrap(), &msg);
-                               let should_forward = match self.message_handler.route_handler.handle_channel_update(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               };
-
-                               if should_forward {
-                                       // TODO: forward msg along to all our other peers!
+                               if self.message_handler.route_handler.handle_channel_update(&msg)
+                                               .map_err(|e| -> MessageHandlingError { e.into() })? {
+                                       should_forward = Some(wire::Message::ChannelUpdate(msg));
                                }
                        },
                        wire::Message::QueryShortChannelIds(msg) => {
@@ -1008,7 +1010,71 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                log_trace!(self.logger, "Received unknown odd message of type {}, ignoring", msg_type);
                        }
                };
-               Ok(())
+               Ok(should_forward)
+       }
+
+       fn forward_broadcast_msg(&self, peers: &mut PeerHolder<Descriptor>, msg: &wire::Message, except_node: Option<&PublicKey>) {
+               match msg {
+                       wire::Message::ChannelAnnouncement(ref msg) => {
+                               let encoded_msg = encode_msg!(msg);
+
+                               for (_, peer) in peers.peers.iter_mut() {
+                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                                       !peer.should_forward_channel_announcement(msg.contents.short_channel_id) {
+                                               continue
+                                       }
+                                       if peer.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP {
+                                               continue;
+                                       }
+                                       if peer.their_node_id.as_ref() == Some(&msg.contents.node_id_1) ||
+                                          peer.their_node_id.as_ref() == Some(&msg.contents.node_id_2) {
+                                               continue;
+                                       }
+                                       if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
+                                               continue;
+                                       }
+                                       peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
+                               }
+                       },
+                       wire::Message::NodeAnnouncement(ref msg) => {
+                               let encoded_msg = encode_msg!(msg);
+
+                               for (_, peer) in peers.peers.iter_mut() {
+                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                                       !peer.should_forward_node_announcement(msg.contents.node_id) {
+                                               continue
+                                       }
+                                       if peer.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP {
+                                               continue;
+                                       }
+                                       if peer.their_node_id.as_ref() == Some(&msg.contents.node_id) {
+                                               continue;
+                                       }
+                                       if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
+                                               continue;
+                                       }
+                                       peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
+                               }
+                       },
+                       wire::Message::ChannelUpdate(ref msg) => {
+                               let encoded_msg = encode_msg!(msg);
+
+                               for (_, peer) in peers.peers.iter_mut() {
+                                       if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
+                                                       !peer.should_forward_channel_announcement(msg.contents.short_channel_id)  {
+                                               continue
+                                       }
+                                       if peer.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_DROP_GOSSIP {
+                                               continue;
+                                       }
+                                       if except_node.is_some() && peer.their_node_id.as_ref() == except_node {
+                                               continue;
+                                       }
+                                       peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
+                               }
+                       },
+                       _ => debug_assert!(false, "We shouldn't attempt to forward anything but gossip messages"),
+               }
        }
 
        /// Checks for any events generated by our handlers and processes them. Includes sending most
@@ -1026,24 +1092,21 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                        let peers = &mut *peers_lock;
                        for event in events_generated.drain(..) {
                                macro_rules! get_peer_for_forwarding {
-                                       ($node_id: expr, $handle_no_such_peer: block) => {
+                                       ($node_id: expr) => {
                                                {
-                                                       let descriptor = match peers.node_id_to_descriptor.get($node_id) {
-                                                               Some(descriptor) => descriptor.clone(),
+                                                       match peers.node_id_to_descriptor.get($node_id) {
+                                                               Some(descriptor) => match peers.peers.get_mut(&descriptor) {
+                                                                       Some(peer) => {
+                                                                               if peer.their_features.is_none() {
+                                                                                       continue;
+                                                                               }
+                                                                               peer
+                                                                       },
+                                                                       None => panic!("Inconsistent peers set state!"),
+                                                               },
                                                                None => {
-                                                                       $handle_no_such_peer;
                                                                        continue;
                                                                },
-                                                       };
-                                                       match peers.peers.get_mut(&descriptor) {
-                                                               Some(peer) => {
-                                                                       if peer.their_features.is_none() {
-                                                                               $handle_no_such_peer;
-                                                                               continue;
-                                                                       }
-                                                                       (descriptor, peer)
-                                                               },
-                                                               None => panic!("Inconsistent peers set state!"),
                                                        }
                                                }
                                        }
@@ -1053,65 +1116,46 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                log_trace!(self.logger, "Handling SendAcceptChannel event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Drop the pending channel? (or just let it timeout, but that sucks)
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendOpenChannel { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendOpenChannel event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Drop the pending channel? (or just let it timeout, but that sucks)
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendFundingCreated { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendFundingCreated event in peer_handler for node {} for channel {} (which becomes {})",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.temporary_channel_id),
                                                                log_funding_channel_id!(msg.funding_txid, msg.funding_output_index));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: generate a DiscardFunding event indicating to the wallet that
-                                                               //they should just throw away this funding transaction
-                                                       });
+                                               // TODO: If the peer is gone we should generate a DiscardFunding event
+                                               // indicating to the wallet that they should just throw away this funding transaction
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendFundingSigned { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendFundingSigned event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: generate a DiscardFunding event indicating to the wallet that
-                                                               //they should just throw away this funding transaction
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendFundingLocked { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendFundingLocked event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendAnnouncementSignatures { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendAnnouncementSignatures event in peer_handler for node {} for channel {})",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: generate a DiscardFunding event indicating to the wallet that
-                                                               //they should just throw away this funding transaction
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::UpdateHTLCs { ref node_id, updates: msgs::CommitmentUpdate { ref update_add_htlcs, ref update_fulfill_htlcs, ref update_fail_htlcs, ref update_fail_malformed_htlcs, ref update_fee, ref commitment_signed } } => {
                                                log_trace!(self.logger, "Handling UpdateHTLCs event in peer_handler for node {} with {} adds, {} fulfills, {} fails for channel {}",
@@ -1120,9 +1164,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                update_fulfill_htlcs.len(),
                                                                update_fail_htlcs.len(),
                                                                log_bytes!(commitment_signed.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                for msg in update_add_htlcs {
                                                        peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
                                                }
@@ -1139,101 +1181,52 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                        peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
                                                }
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(commitment_signed)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendRevokeAndACK { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendRevokeAndACK event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendClosingSigned { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendClosingSigned event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendShutdown { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling Shutdown event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendChannelReestablish { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendChannelReestablish event in peer_handler for node {} for channel {}",
                                                                log_pubkey!(node_id),
                                                                log_bytes!(msg.channel_id));
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                               //TODO: Do whatever we're gonna do for handling dropped messages
-                                                       });
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
-                                       MessageSendEvent::BroadcastChannelAnnouncement { ref msg, ref update_msg } => {
+                                       MessageSendEvent::BroadcastChannelAnnouncement { msg, update_msg } => {
                                                log_trace!(self.logger, "Handling BroadcastChannelAnnouncement event in peer_handler for short channel id {}", msg.contents.short_channel_id);
-                                               if self.message_handler.route_handler.handle_channel_announcement(msg).is_ok() && self.message_handler.route_handler.handle_channel_update(update_msg).is_ok() {
-                                                       let encoded_msg = encode_msg!(msg);
-                                                       let encoded_update_msg = encode_msg!(update_msg);
-
-                                                       for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
-                                                                               !peer.should_forward_channel_announcement(msg.contents.short_channel_id) {
-                                                                       continue
-                                                               }
-                                                               match peer.their_node_id {
-                                                                       None => continue,
-                                                                       Some(their_node_id) => {
-                                                                               if their_node_id == msg.contents.node_id_1 || their_node_id == msg.contents.node_id_2 {
-                                                                                       continue
-                                                                               }
-                                                                       }
-                                                               }
-                                                               peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
-                                                               peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_update_msg[..]));
-                                                               self.do_attempt_write_data(&mut (*descriptor).clone(), peer);
-                                                       }
+                                               if self.message_handler.route_handler.handle_channel_announcement(&msg).is_ok() && self.message_handler.route_handler.handle_channel_update(&update_msg).is_ok() {
+                                                       self.forward_broadcast_msg(peers, &wire::Message::ChannelAnnouncement(msg), None);
+                                                       self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(update_msg), None);
                                                }
                                        },
-                                       MessageSendEvent::BroadcastNodeAnnouncement { ref msg } => {
+                                       MessageSendEvent::BroadcastNodeAnnouncement { msg } => {
                                                log_trace!(self.logger, "Handling BroadcastNodeAnnouncement event in peer_handler");
-                                               if self.message_handler.route_handler.handle_node_announcement(msg).is_ok() {
-                                                       let encoded_msg = encode_msg!(msg);
-
-                                                       for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
-                                                                               !peer.should_forward_node_announcement(msg.contents.node_id) {
-                                                                       continue
-                                                               }
-                                                               peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
-                                                               self.do_attempt_write_data(&mut (*descriptor).clone(), peer);
-                                                       }
+                                               if self.message_handler.route_handler.handle_node_announcement(&msg).is_ok() {
+                                                       self.forward_broadcast_msg(peers, &wire::Message::NodeAnnouncement(msg), None);
                                                }
                                        },
-                                       MessageSendEvent::BroadcastChannelUpdate { ref msg } => {
+                                       MessageSendEvent::BroadcastChannelUpdate { msg } => {
                                                log_trace!(self.logger, "Handling BroadcastChannelUpdate event in peer_handler for short channel id {}", msg.contents.short_channel_id);
-                                               if self.message_handler.route_handler.handle_channel_update(msg).is_ok() {
-                                                       let encoded_msg = encode_msg!(msg);
-
-                                                       for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-                                                               if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_features.is_none() ||
-                                                                               !peer.should_forward_channel_announcement(msg.contents.short_channel_id)  {
-                                                                       continue
-                                                               }
-                                                               peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
-                                                               self.do_attempt_write_data(&mut (*descriptor).clone(), peer);
-                                                       }
+                                               if self.message_handler.route_handler.handle_channel_update(&msg).is_ok() {
+                                                       self.forward_broadcast_msg(peers, &wire::Message::ChannelUpdate(msg), None);
                                                }
                                        },
                                        MessageSendEvent::PaymentFailureNetworkUpdate { ref update } => {
@@ -1243,7 +1236,6 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                match *action {
                                                        msgs::ErrorAction::DisconnectPeer { ref msg } => {
                                                                if let Some(mut descriptor) = peers.node_id_to_descriptor.remove(node_id) {
-                                                                       peers.peers_needing_send.remove(&descriptor);
                                                                        if let Some(mut peer) = peers.peers.remove(&descriptor) {
                                                                                if let Some(ref msg) = *msg {
                                                                                        log_trace!(self.logger, "Handling DisconnectPeer HandleError event in peer_handler for node {} with message {}",
@@ -1266,23 +1258,18 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                log_trace!(self.logger, "Handling SendErrorMessage HandleError event in peer_handler for node {} with message {}",
                                                                                log_pubkey!(node_id),
                                                                                msg.data);
-                                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {
-                                                                       //TODO: Do whatever we're gonna do for handling dropped messages
-                                                               });
+                                                               let peer = get_peer_for_forwarding!(node_id);
                                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                                               self.do_attempt_write_data(&mut descriptor, peer);
                                                        },
                                                }
                                        },
                                        MessageSendEvent::SendChannelRangeQuery { ref node_id, ref msg } => {
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {});
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        },
                                        MessageSendEvent::SendShortIdsQuery { ref node_id, ref msg } => {
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {});
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        }
                                        MessageSendEvent::SendReplyChannelRange { ref node_id, ref msg } => {
                                                log_trace!(self.logger, "Handling SendReplyChannelRange event in peer_handler for node {} with num_scids={} first_blocknum={} number_of_blocks={}, sync_complete={}",
@@ -1291,18 +1278,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                        msg.first_blocknum,
                                                        msg.number_of_blocks,
                                                        msg.sync_complete);
-                                               let (mut descriptor, peer) = get_peer_for_forwarding!(node_id, {});
+                                               let peer = get_peer_for_forwarding!(node_id);
                                                peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encode_msg!(msg)));
-                                               self.do_attempt_write_data(&mut descriptor, peer);
                                        }
                                }
                        }
 
-                       for mut descriptor in peers.peers_needing_send.drain() {
-                               match peers.peers.get_mut(&descriptor) {
-                                       Some(peer) => self.do_attempt_write_data(&mut descriptor, peer),
-                                       None => panic!("Inconsistent peers set state!"),
-                               }
+                       for (descriptor, peer) in peers.peers.iter_mut() {
+                               self.do_attempt_write_data(&mut (*descriptor).clone(), peer);
                        }
                }
        }
@@ -1321,7 +1304,6 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
 
        fn disconnect_event_internal(&self, descriptor: &Descriptor, no_connection_possible: bool) {
                let mut peers = self.peers.lock().unwrap();
-               peers.peers_needing_send.remove(descriptor);
                let peer_option = peers.peers.remove(descriptor);
                match peer_option {
                        None => panic!("Descriptor for disconnect_event is not already known to PeerManager"),
@@ -1349,7 +1331,6 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                if let Some(mut descriptor) = peers_lock.node_id_to_descriptor.remove(&node_id) {
                        log_trace!(self.logger, "Disconnecting peer with id {} due to client request", node_id);
                        peers_lock.peers.remove(&descriptor);
-                       peers_lock.peers_needing_send.remove(&descriptor);
                        self.message_handler.chan_handler.peer_disconnected(&node_id, no_connection_possible);
                        descriptor.disconnect_socket();
                }
@@ -1363,14 +1344,12 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                let mut peers_lock = self.peers.lock().unwrap();
                {
                        let peers = &mut *peers_lock;
-                       let peers_needing_send = &mut peers.peers_needing_send;
                        let node_id_to_descriptor = &mut peers.node_id_to_descriptor;
                        let peers = &mut peers.peers;
                        let mut descriptors_needing_disconnect = Vec::new();
 
                        peers.retain(|descriptor, peer| {
                                if peer.awaiting_pong {
-                                       peers_needing_send.remove(descriptor);
                                        descriptors_needing_disconnect.push(descriptor.clone());
                                        match peer.their_node_id {
                                                Some(node_id) => {
@@ -1494,7 +1473,9 @@ mod tests {
                let initial_data = peer_b.new_outbound_connection(a_id, fd_b.clone()).unwrap();
                peer_a.new_inbound_connection(fd_a.clone()).unwrap();
                assert_eq!(peer_a.read_event(&mut fd_a, &initial_data).unwrap(), false);
+               peer_a.process_events();
                assert_eq!(peer_b.read_event(&mut fd_b, &fd_a.outbound_data.lock().unwrap().split_off(0)).unwrap(), false);
+               peer_b.process_events();
                assert_eq!(peer_a.read_event(&mut fd_a, &fd_b.outbound_data.lock().unwrap().split_off(0)).unwrap(), false);
                (fd_a.clone(), fd_b.clone())
        }
@@ -1533,10 +1514,12 @@ mod tests {
 
                // peers[0] awaiting_pong is set to true, but the Peer is still connected
                peers[0].timer_tick_occurred();
+               peers[0].process_events();
                assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 1);
 
                // Since timer_tick_occurred() is called again when awaiting_pong is true, all Peers are disconnected
                peers[0].timer_tick_occurred();
+               peers[0].process_events();
                assert_eq!(peers[0].peers.lock().unwrap().peers.len(), 0);
        }
 
@@ -1557,7 +1540,9 @@ mod tests {
                let (mut fd_a, mut fd_b) = establish_connection(&peers[0], &peers[1]);
 
                // Make each peer to read the messages that the other peer just wrote to them.
+               peers[0].process_events();
                peers[1].read_event(&mut fd_b, &fd_a.outbound_data.lock().unwrap().split_off(0)).unwrap();
+               peers[1].process_events();
                peers[0].read_event(&mut fd_a, &fd_b.outbound_data.lock().unwrap().split_off(0)).unwrap();
 
                // Check that each peer has received the expected number of channel updates and channel