Conditionally advertise OM support in InitFeatures

Based on whether the PeerManager's OnionMessageHandler supports forwarding

Author: valentinewallace

lightning/src/ln/features.rs

@@ -548,6 +548,12 @@ impl InitFeatures {
 	pub(crate) fn to_context<C: sealed::Context>(&self) -> Features<C> {
 		self.to_context_internal()
 	}
+
+	pub(crate) fn known_without_onion_messages() -> Self {
+		let mut features = Self::known();
+		features.flags[4] &= 0b00111111;
+		features
+	}
 }
 
 impl NodeFeatures {

lightning/src/ln/peer_handler.rs

@@ -1033,7 +1033,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 
 								peer.their_node_id = Some(their_node_id);
 								insert_node_id!();
-								let features = InitFeatures::known();
+								let features = if self.message_handler.onion_message_handler.supports_onion_message_forwarding()
+									{ InitFeatures::known() } else { InitFeatures::known_without_onion_messages() };
 								let resp = msgs::Init { features, remote_network_address: filter_addresses(peer.their_net_address.clone()) };
 								self.enqueue_message(peer, &resp);
 								peer.awaiting_pong_timer_tick_intervals = 0;
@@ -1045,7 +1046,8 @@ impl<Descriptor: SocketDescriptor, CM: Deref, RM: Deref, OM: Deref, L: Deref, CM
 								peer.pending_read_is_header = true;
 								peer.their_node_id = Some(their_node_id);
 								insert_node_id!();
-								let features = InitFeatures::known();
+								let features = if self.message_handler.onion_message_handler.supports_onion_message_forwarding()
+									{ InitFeatures::known() } else { InitFeatures::known_without_onion_messages() };
 								let resp = msgs::Init { features, remote_network_address: filter_addresses(peer.their_net_address.clone()) };
 								self.enqueue_message(peer, &resp);
 								peer.awaiting_pong_timer_tick_intervals = 0;