Pass channel updates to ChannelManager and Channel.

This will be used to expose forwarding info for route hints in the next commit.

Co-authored-by: Valentine Wallace <vwallace@protonmail.com>
Co-authored-by: Antoine Riard <ariard@student.42.fr>

lightning-net-tokio/src/lib.rs

@@ -561,6 +561,7 @@ mod tests {
 		fn handle_revoke_and_ack(&self, _their_node_id: &PublicKey, _msg: &RevokeAndACK) {}
 		fn handle_update_fee(&self, _their_node_id: &PublicKey, _msg: &UpdateFee) {}
 		fn handle_announcement_signatures(&self, _their_node_id: &PublicKey, _msg: &AnnouncementSignatures) {}
+		fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &ChannelUpdate) {}
 		fn peer_disconnected(&self, their_node_id: &PublicKey, _no_connection_possible: bool) {
 			if *their_node_id == self.expected_pubkey {
 				self.disconnected_flag.store(true, Ordering::SeqCst);

lightning/src/ln/channel.rs

@@ -4132,6 +4132,20 @@ impl<Signer: Sign> Channel<Signer> {
 		}
 	}
 
+	pub fn channel_update(&mut self, msg: &msgs::ChannelUpdate) -> Result<(), ChannelError> {
+		let usable_channel_value_msat = (self.channel_value_satoshis - self.counterparty_selected_channel_reserve_satoshis) * 1000;
+		if msg.contents.htlc_minimum_msat >= usable_channel_value_msat {
+			return Err(ChannelError::Close("Minimum htlc value is greater than channel value".to_string()));
+		}
+		self.counterparty_forwarding_info = Some(CounterpartyForwardingInfo {
+			fee_base_msat: msg.contents.fee_base_msat,
+			fee_proportional_millionths: msg.contents.fee_proportional_millionths,
+			cltv_expiry_delta: msg.contents.cltv_expiry_delta
+		});
+
+		Ok(())
+	}
+
 	/// Begins the shutdown process, getting a message for the remote peer and returning all
 	/// holding cell HTLCs for payment failure.
 	pub fn get_shutdown(&mut self) -> Result<(msgs::Shutdown, Vec<(HTLCSource, PaymentHash)>), APIError> {

lightning/src/ln/channelmanager.rs

@@ -2994,6 +2994,29 @@ impl<Signer: Sign, M: Deref, T: Deref, K: Deref, F: Deref, L: Deref> ChannelMana
 		Ok(())
 	}
 
+	fn internal_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) -> Result<(), MsgHandleErrInternal> {
+		let mut channel_state_lock = self.channel_state.lock().unwrap();
+		let channel_state = &mut *channel_state_lock;
+		let chan_id = match channel_state.short_to_id.get(&msg.contents.short_channel_id) {
+			Some(chan_id) => chan_id.clone(),
+			None => {
+				// It's not a local channel
+				return Ok(())
+			}
+		};
+		match channel_state.by_id.entry(chan_id) {
+			hash_map::Entry::Occupied(mut chan) => {
+				if chan.get().get_counterparty_node_id() != *counterparty_node_id {
+					// TODO: see issue #153, need a consistent behavior on obnoxious behavior from random node
+					return Err(MsgHandleErrInternal::send_err_msg_no_close("Got a message for a channel from the wrong node!".to_owned(), chan_id));
+				}
+				try_chan_entry!(self, chan.get_mut().channel_update(&msg), channel_state, chan);
+			},
+			hash_map::Entry::Vacant(_) => unreachable!()
+		}
+		Ok(())
+	}
+
 	fn internal_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) -> Result<(), MsgHandleErrInternal> {
 		let mut channel_state_lock = self.channel_state.lock().unwrap();
 		let channel_state = &mut *channel_state_lock;
@@ -3517,6 +3540,11 @@ impl<Signer: Sign, M: Deref + Sync + Send, T: Deref + Sync + Send, K: Deref + Sy
 		let _ = handle_error!(self, self.internal_announcement_signatures(counterparty_node_id, msg), *counterparty_node_id);
 	}
 
+	fn handle_channel_update(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelUpdate) {
+		let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
+		let _ = handle_error!(self, self.internal_channel_update(counterparty_node_id, msg), *counterparty_node_id);
+	}
+
 	fn handle_channel_reestablish(&self, counterparty_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
 		let _persistence_guard = PersistenceNotifierGuard::new(&self.total_consistency_lock, &self.persistence_notifier);
 		let _ = handle_error!(self, self.internal_channel_reestablish(counterparty_node_id, msg), *counterparty_node_id);

lightning/src/ln/msgs.rs

@@ -796,6 +796,9 @@ pub trait ChannelMessageHandler : MessageSendEventsProvider + Send + Sync {
 	/// Handle an incoming channel_reestablish message from the given peer.
 	fn handle_channel_reestablish(&self, their_node_id: &PublicKey, msg: &ChannelReestablish);
 
+	/// Handle an incoming channel update from the given peer.
+	fn handle_channel_update(&self, their_node_id: &PublicKey, msg: &ChannelUpdate);
+
 	// Error:
 	/// Handle an incoming error message from the given peer.
 	fn handle_error(&self, their_node_id: &PublicKey, msg: &ErrorMessage);

lightning/src/ln/peer_handler.rs

@@ -142,6 +142,8 @@ impl ChannelMessageHandler for ErroringMessageHandler {
 	fn handle_channel_reestablish(&self, their_node_id: &PublicKey, msg: &msgs::ChannelReestablish) {
 		ErroringMessageHandler::push_error(self, their_node_id, msg.channel_id);
 	}
+	// msgs::ChannelUpdate does not contain the channel_id field, so we just drop them.
+	fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &msgs::ChannelUpdate) {}
 	fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}
 	fn peer_connected(&self, _their_node_id: &PublicKey, _msg: &msgs::Init) {}
 	fn handle_error(&self, _their_node_id: &PublicKey, _msg: &msgs::ErrorMessage) {}
@@ -970,6 +972,7 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, L: Deref> PeerManager<D
 				}
 			},
 			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()); },

lightning/src/util/test_utils.rs

@@ -231,6 +231,7 @@ impl msgs::ChannelMessageHandler for TestChannelMessageHandler {
 	fn handle_commitment_signed(&self, _their_node_id: &PublicKey, _msg: &msgs::CommitmentSigned) {}
 	fn handle_revoke_and_ack(&self, _their_node_id: &PublicKey, _msg: &msgs::RevokeAndACK) {}
 	fn handle_update_fee(&self, _their_node_id: &PublicKey, _msg: &msgs::UpdateFee) {}
+	fn handle_channel_update(&self, _their_node_id: &PublicKey, _msg: &msgs::ChannelUpdate) {}
 	fn handle_announcement_signatures(&self, _their_node_id: &PublicKey, _msg: &msgs::AnnouncementSignatures) {}
 	fn handle_channel_reestablish(&self, _their_node_id: &PublicKey, _msg: &msgs::ChannelReestablish) {}
 	fn peer_disconnected(&self, _their_node_id: &PublicKey, _no_connection_possible: bool) {}