From: Matt Corallo <git@bluematt.me>
Date: Thu, 10 Jun 2021 18:46:24 +0000 (+0000)
Subject: Drop peers_needing_send tracking and try to write for each peer
X-Git-Url: http://git.bitcoin.ninja/?a=commitdiff_plain;h=41bb42a99cd9df2d297ae938303b15deefe66e62;p=rust-lightning

Drop peers_needing_send tracking and try to write for each peer

We do a lot of work to track which peers have buffers which need
to be flushed, when we could instead just try to flush ever peer's
buffer.
---

diff --git a/lightning/src/ln/peer_handler.rs b/lightning/src/ln/peer_handler.rs
index 8695ffdb8..dd3955c19 100644
--- a/lightning/src/ln/peer_handler.rs
+++ b/lightning/src/ln/peer_handler.rs
@@ -32,7 +32,7 @@ use routing::network_graph::NetGraphMsgHandler;
 
 use prelude::*;
 use alloc::collections::LinkedList;
-use std::collections::{HashMap,hash_map,HashSet};
+use std::collections::{HashMap,hash_map};
 use std::sync::{Arc, Mutex};
 use core::sync::atomic::{AtomicUsize, Ordering};
 use core::{cmp, hash, fmt, mem};
@@ -286,9 +286,6 @@ 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>,
 }
@@ -419,7 +416,6 @@ 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,
@@ -651,14 +647,13 @@ 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> {
@@ -702,7 +697,7 @@ 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;
 												},
 											}
@@ -744,7 +739,7 @@ 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[..]));
@@ -754,7 +749,7 @@ 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 {
@@ -802,7 +797,7 @@ 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) => {
@@ -837,7 +832,7 @@ 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
@@ -872,7 +867,6 @@ 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()));
@@ -907,7 +901,7 @@ 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) => {
@@ -1029,7 +1023,7 @@ 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 (_, 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
@@ -1045,13 +1039,12 @@ 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 (_, 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
@@ -1066,13 +1059,12 @@ 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 (_, 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
@@ -1084,7 +1076,6 @@ 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());
 				}
 			},
 			_ => debug_assert!(false, "We shouldn't attempt to forward anything but gossip messages"),
@@ -1131,17 +1122,15 @@ 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 {})",
@@ -1150,9 +1139,8 @@ 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 {}",
@@ -1160,25 +1148,22 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
 								log_bytes!(msg.channel_id));
 						// 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::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 {}",
@@ -1187,7 +1172,7 @@ 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)));
 						}
@@ -1204,39 +1189,34 @@ 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);
@@ -1264,7 +1244,6 @@ 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 {}",
@@ -1287,21 +1266,18 @@ 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={}",
@@ -1310,18 +1286,14 @@ 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, ref mut peer) in peers.peers.iter_mut() {
+				self.do_attempt_write_data(&mut (*descriptor).clone(), peer);
 			}
 		}
 	}
@@ -1340,7 +1312,6 @@ 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"),
@@ -1368,7 +1339,6 @@ 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();
 		}
@@ -1382,14 +1352,12 @@ 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) => {