Merge pull request #4133 from wpaulino/send-gossip-on-peer-conn

peer: send local node announcement upon establishing peer connections

peer.go

@@ -425,6 +425,19 @@ func (p *peer) Start() error {
 		}
 	}
 
+	// Node announcements don't propagate very well throughout the network
+	// as there isn't a way to efficiently query for them through their
+	// timestamp, mostly affecting nodes that were offline during the time
+	// of broadcast. We'll resend our node announcement to the remote peer
+	// as a best-effort delivery such that it can also propagate to their
+	// peers. To ensure they can successfully process it in most cases,
+	// we'll only resend it as long as we have at least one confirmed
+	// advertised channel with the remote peer.
+	//
+	// TODO(wilmer): Remove this once we're able to query for node
+	// announcements through their timestamps.
+	p.maybeSendNodeAnn(activeChans)
+
 	return nil
 }
 
@@ -688,6 +701,37 @@ func (p *peer) addLink(chanPoint *wire.OutPoint,
 	return p.server.htlcSwitch.AddLink(link)
 }
 
+// maybeSendNodeAnn sends our node announcement to the remote peer if at least
+// one confirmed advertised channel exists with them.
+func (p *peer) maybeSendNodeAnn(channels []*channeldb.OpenChannel) {
+	hasConfirmedPublicChan := false
+	for _, channel := range channels {
+		if channel.IsPending {
+			continue
+		}
+		if channel.ChannelFlags&lnwire.FFAnnounceChannel == 0 {
+			continue
+		}
+
+		hasConfirmedPublicChan = true
+		break
+	}
+	if !hasConfirmedPublicChan {
+		return
+	}
+
+	ourNodeAnn, err := p.server.genNodeAnnouncement(false)
+	if err != nil {
+		srvrLog.Debugf("Unable to retrieve node announcement: %v", err)
+		return
+	}
+
+	if err := p.SendMessageLazy(false, &ourNodeAnn); err != nil {
+		srvrLog.Debugf("Unable to resend node announcement to %x: %v",
+			p.pubKeyBytes, err)
+	}
+}
+
 // WaitForDisconnect waits until the peer has disconnected. A peer may be
 // disconnected if the local or remote side terminating the connection, or an
 // irrecoverable protocol error has been encountered. This method will only