Limit OnionMessenger event buffer size.

[rust-lightning] / lightning / src / onion_message / messenger.rs

diff --git a/lightning/src/onion_message/messenger.rs b/lightning/src/onion_message/messenger.rs
index d956b392a39631a6ce2ca761d0b457e7bb252da0..e71066561ec2fa18c054a9a152051ad865c3df2f 100644 (file)
--- a/lightning/src/onion_message/messenger.rs
+++ b/lightning/src/onion_message/messenger.rs
@@ -943,6 +943,27 @@ where
                }
        }
 
+       /// Forwards an [`OnionMessage`] to `peer_node_id`. Useful if we initialized
+       /// the [`OnionMessenger`] with [`Self::new_with_offline_peer_interception`]
+       /// and want to forward a previously intercepted onion message to a peer that
+       /// has just come online.
+       pub fn forward_onion_message(
+               &self, message: OnionMessage, peer_node_id: &PublicKey
+       ) -> Result<(), SendError> {
+               let mut message_recipients = self.message_recipients.lock().unwrap();
+               if outbound_buffer_full(&peer_node_id, &message_recipients) {
+                       return Err(SendError::BufferFull);
+               }
+
+               match message_recipients.entry(*peer_node_id) {
+                       hash_map::Entry::Occupied(mut e) if e.get().is_connected() => {
+                               e.get_mut().enqueue_message(message);
+                               Ok(())
+                       },
+                       _ => Err(SendError::InvalidFirstHop(*peer_node_id))
+               }
+       }
+
        #[cfg(any(test, feature = "_test_utils"))]
        pub fn send_onion_message_using_path<T: OnionMessageContents>(
                &self, path: OnionMessagePath, contents: T, reply_path: Option<BlindedPath>
@@ -986,6 +1007,20 @@ where
                }
                msgs
        }
+
+       fn enqueue_event(&self, event: Event) {
+               const MAX_EVENTS_BUFFER_SIZE: usize = (1 << 10) * 256;
+               let mut pending_events = self.pending_events.lock().unwrap();
+               let total_buffered_bytes: usize = pending_events
+                       .iter()
+                       .map(|ev| ev.serialized_length())
+                       .sum();
+               if total_buffered_bytes >= MAX_EVENTS_BUFFER_SIZE {
+                       log_trace!(self.logger, "Dropping event {:?}: buffer full", event);
+                       return
+               }
+               pending_events.push(event);
+       }
 }
 
 fn outbound_buffer_full(peer_node_id: &PublicKey, buffer: &HashMap<PublicKey, OnionMessageRecipient>) -> bool {
@@ -1113,7 +1148,7 @@ where
                                                log_trace!(logger, "Forwarding an onion message to peer {}", next_node_id);
                                        },
                                        _ if self.intercept_messages_for_offline_peers => {
-                                               self.pending_events.lock().unwrap().push(
+                                               self.enqueue_event(
                                                        Event::OnionMessageIntercepted {
                                                                peer_node_id: next_node_id, message: onion_message
                                                        }
@@ -1141,7 +1176,7 @@ where
                                .or_insert_with(|| OnionMessageRecipient::ConnectedPeer(VecDeque::new()))
                                .mark_connected();
                        if self.intercept_messages_for_offline_peers {
-                               self.pending_events.lock().unwrap().push(
+                               self.enqueue_event(
                                        Event::OnionMessagePeerConnected { peer_node_id: *their_node_id }
                                );
                        }