Add a note that `peer_disconnected` impls must be idempotent

[rust-lightning] / lightning / src / ln / msgs.rs

diff --git a/lightning/src/ln/msgs.rs b/lightning/src/ln/msgs.rs
index 190907ce26e3a9f01edcc613d1112086692c6567..98831137b303b6a9edaae8e393bd32fae2ec48ec 100644 (file)
--- a/lightning/src/ln/msgs.rs
+++ b/lightning/src/ln/msgs.rs
@@ -883,6 +883,9 @@ pub trait ChannelMessageHandler : MessageSendEventsProvider {
        /// is believed to be possible in the future (eg they're sending us messages we don't
        /// understand or indicate they require unknown feature bits), no_connection_possible is set
        /// and any outstanding channels should be failed.
+       ///
+       /// Note that in some rare cases this may be called without a corresponding
+       /// [`Self::peer_connected`].
        fn peer_disconnected(&self, their_node_id: &PublicKey, no_connection_possible: bool);
 
        /// Handle a peer reconnecting, possibly generating channel_reestablish message(s).
@@ -896,6 +899,19 @@ pub trait ChannelMessageHandler : MessageSendEventsProvider {
        // Error:
        /// Handle an incoming error message from the given peer.
        fn handle_error(&self, their_node_id: &PublicKey, msg: &ErrorMessage);
+
+       // Handler information:
+       /// Gets the node feature flags which this handler itself supports. All available handlers are
+       /// queried similarly and their feature flags are OR'd together to form the [`NodeFeatures`]
+       /// which are broadcasted in our [`NodeAnnouncement`] message.
+       fn provided_node_features(&self) -> NodeFeatures;
+
+       /// Gets the init feature flags which should be sent to the given peer. All available handlers
+       /// are queried similarly and their feature flags are OR'd together to form the [`InitFeatures`]
+       /// which are sent in our [`Init`] message.
+       ///
+       /// Note that this method is called before [`Self::peer_connected`].
+       fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
 /// A trait to describe an object which can receive routing messages.
@@ -943,12 +959,46 @@ pub trait RoutingMessageHandler : MessageSendEventsProvider {
        /// Handles when a peer asks us to send routing gossip messages for a
        /// list of short_channel_ids.
        fn handle_query_short_channel_ids(&self, their_node_id: &PublicKey, msg: QueryShortChannelIds) -> Result<(), LightningError>;
+
+       // Handler information:
+       /// Gets the node feature flags which this handler itself supports. All available handlers are
+       /// queried similarly and their feature flags are OR'd together to form the [`NodeFeatures`]
+       /// which are broadcasted in our [`NodeAnnouncement`] message.
+       fn provided_node_features(&self) -> NodeFeatures;
+       /// Gets the init feature flags which should be sent to the given peer. All available handlers
+       /// are queried similarly and their feature flags are OR'd together to form the [`InitFeatures`]
+       /// which are sent in our [`Init`] message.
+       ///
+       /// Note that this method is called before [`Self::peer_connected`].
+       fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
 /// A trait to describe an object that can receive onion messages.
 pub trait OnionMessageHandler : OnionMessageProvider {
        /// Handle an incoming onion_message message from the given peer.
        fn handle_onion_message(&self, peer_node_id: &PublicKey, msg: &OnionMessage);
+       /// Called when a connection is established with a peer. Can be used to track which peers
+       /// advertise onion message support and are online.
+       fn peer_connected(&self, their_node_id: &PublicKey, init: &Init);
+       /// Indicates a connection to the peer failed/an existing connection was lost. Allows handlers to
+       /// drop and refuse to forward onion messages to this peer.
+       ///
+       /// Note that in some rare cases this may be called without a corresponding
+       /// [`Self::peer_connected`].
+       fn peer_disconnected(&self, their_node_id: &PublicKey, no_connection_possible: bool);
+
+       // Handler information:
+       /// Gets the node feature flags which this handler itself supports. All available handlers are
+       /// queried similarly and their feature flags are OR'd together to form the [`NodeFeatures`]
+       /// which are broadcasted in our [`NodeAnnouncement`] message.
+       fn provided_node_features(&self) -> NodeFeatures;
+
+       /// Gets the init feature flags which should be sent to the given peer. All available handlers
+       /// are queried similarly and their feature flags are OR'd together to form the [`InitFeatures`]
+       /// which are sent in our [`Init`] message.
+       ///
+       /// Note that this method is called before [`Self::peer_connected`].
+       fn provided_init_features(&self, their_node_id: &PublicKey) -> InitFeatures;
 }
 
 mod fuzzy_internal_msgs {