[peer_handler] Drop unused return from get_peer_for_forwarding!()
[rust-lightning] / lightning / src / ln / peer_handler.rs
index d7d52a0584525ba8b762147401387acd119d734a..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;
@@ -644,14 +648,13 @@ 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> {
@@ -695,7 +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;
                                                                                                },
                                                                                        }
@@ -737,7 +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[..]));
@@ -747,7 +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 {
@@ -795,7 +798,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                                        }
                                                                                };
 
-                                                                               match self.handle_message(&mut peers.peers_needing_send, peer, peer_descriptor.clone(), message) {
+                                                                               match self.handle_message(peer, message) {
                                                                                        Err(handling_error) => match handling_error {
                                                                                                MessageHandlingError::PeerHandleError(e) => { return Err(e) },
                                                                                                MessageHandlingError::LightningError(e) => {
@@ -814,7 +817,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                }
                                        }
 
-                                       peer.pending_outbound_buffer.len() > 10 // pause_read
+                                       peer.pending_outbound_buffer.len() > OUTBOUND_BUFFER_LIMIT_READ_PAUSE // pause_read
                                }
                        };
 
@@ -830,7 +833,7 @@ 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
        /// Returns the message back if it needs to be broadcasted to all other peers.
-       fn handle_message(&self, peers_needing_send: &mut HashSet<Descriptor>, peer: &mut Peer, peer_descriptor: Descriptor, message: wire::Message) -> Result<Option<wire::Message>, MessageHandlingError> {
+       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
@@ -865,7 +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()));
@@ -900,7 +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) => {
@@ -964,27 +966,21 @@ 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) => {
-                               if match self.message_handler.route_handler.handle_channel_announcement(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               } {
+                               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) => {
-                               if match self.message_handler.route_handler.handle_node_announcement(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               } {
+                               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);
-                               if match self.message_handler.route_handler.handle_channel_update(&msg) {
-                                       Ok(v) => v,
-                                       Err(e) => { return Err(e.into()); },
-                               } {
+                               if self.message_handler.route_handler.handle_channel_update(&msg)
+                                               .map_err(|e| -> MessageHandlingError { e.into() })? {
                                        should_forward = Some(wire::Message::ChannelUpdate(msg));
                                }
                        },
@@ -1022,11 +1018,14 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                        wire::Message::ChannelAnnouncement(ref msg) => {
                                let encoded_msg = encode_msg!(msg);
 
-                               for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
+                               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;
@@ -1035,17 +1034,19 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                continue;
                                        }
                                        peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
-                                       peers.peers_needing_send.insert((*descriptor).clone());
                                }
                        },
                        wire::Message::NodeAnnouncement(ref msg) => {
                                let encoded_msg = encode_msg!(msg);
 
-                               for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
+                               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;
                                        }
@@ -1053,22 +1054,23 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                continue;
                                        }
                                        peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));
-                                       peers.peers_needing_send.insert((*descriptor).clone());
                                }
                        },
                        wire::Message::ChannelUpdate(ref msg) => {
                                let encoded_msg = encode_msg!(msg);
 
-                               for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
+                               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[..]));
-                                       peers.peers_needing_send.insert((*descriptor).clone());
                                }
                        },
                        _ => debug_assert!(false, "We shouldn't attempt to forward anything but gossip messages"),
@@ -1092,20 +1094,19 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                macro_rules! get_peer_for_forwarding {
                                        ($node_id: expr) => {
                                                {
-                                                       let descriptor = match peers.node_id_to_descriptor.get($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 => {
                                                                        continue;
                                                                },
-                                                       };
-                                                       match peers.peers.get_mut(&descriptor) {
-                                                               Some(peer) => {
-                                                                       if peer.their_features.is_none() {
-                                                                               continue;
-                                                                       }
-                                                                       (descriptor, peer)
-                                                               },
-                                                               None => panic!("Inconsistent peers set state!"),
                                                        }
                                                }
                                        }
@@ -1115,17 +1116,15 @@ 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);
+                                               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);
+                                               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 {})",
@@ -1134,33 +1133,29 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
                                                                log_funding_channel_id!(msg.funding_txid, msg.funding_output_index));
                                                // 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 (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::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);
+                                               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);
+                                               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);
+                                               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 {}",
@@ -1169,7 +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);
+                                               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)));
                                                }
@@ -1186,39 +1181,34 @@ 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);
+                                               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);
+                                               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);
+                                               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);
+                                               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 { msg, update_msg } => {
                                                log_trace!(self.logger, "Handling BroadcastChannelAnnouncement event in peer_handler for short channel id {}", msg.contents.short_channel_id);
@@ -1246,7 +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 {}",
@@ -1269,21 +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);
+                                                               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={}",
@@ -1292,18 +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);
                        }
                }
        }
@@ -1322,7 +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"),
@@ -1350,7 +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();
                }
@@ -1364,14 +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) => {