Add proper syncinc check

Author: SWvheerden

src/ln/peer_handler.rs

@@ -109,6 +109,17 @@ impl Peer {
 	pub fn require_sync(&self)->bool{
 		if let msgs::InitSyncTracker::Sync(i) = self.sync_status {i} else {false}
 	}
+
+	/// this function checks if the the channel announcements and updates are allowed to be forwarded to a specific peer.
+	/// If the peer is in syncing state and the channel_id has not been synced then the function returns false as this info will forward at a later stage and
+	/// we dont want to send duplicate messages. If the channel was already synced then we can forward those messages and the function will then return true.
+	pub fn is_channel_allowed_to_forward(&self, channel_id : u64)->bool{
+		match self.sync_status {
+		msgs::InitSyncTracker::Sync(i) => !i,
+		msgs::InitSyncTracker::NodeCounter(_i) => false,
+		msgs::InitSyncTracker::ChannelCounter(i) => (i < channel_id),
+		}
+	}
 }
 
 struct PeerHolder<Descriptor: SocketDescriptor> {
@@ -904,7 +915,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 							let encoded_update_msg = encode_msg!(update_msg, 258);
 
 							for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-								if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() {
+								if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() ||!peer.is_channel_allowed_to_forward(msg.short_channel_id) {
 									continue
 								}
 								match peer.their_node_id {
@@ -927,7 +938,7 @@ impl<Descriptor: SocketDescriptor> PeerManager<Descriptor> {
 							let encoded_msg = encode_msg!(msg, 258);
 
 							for (ref descriptor, ref mut peer) in peers.peers.iter_mut() {
-								if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() || peer.sync_status != msgs::InitSyncTracker::Sync(false)  {
+								if !peer.channel_encryptor.is_ready_for_encryption() || peer.their_global_features.is_none() || !peer.is_channel_allowed_to_forward(msg.short_channel_id)  {
 									continue
 								}
 								peer.pending_outbound_buffer.push_back(peer.channel_encryptor.encrypt_message(&encoded_msg[..]));