identify: only store _reported_ multiaddrs

We still tell the remote host about the observed addr but we don't store it.
That way, we give them a chance to decide if they want to actually use and
advertise it.

Ideally, we'd distinguish between local information and signed routing
information but we don't do that yet.

This should reduce the address explosion issue where peers learn about
multiple (bad) observed addresses for the same peer. It should also give peers
more control over how they can be dialed.

Author: Stebalien

p2p/protocol/identify/id.go

@@ -238,11 +238,8 @@ func (ids *IDService) consumeMessage(mes *pb.Identify, c inet.Conn) {
 		lmaddrs = append(lmaddrs, maddr)
 	}
 
-	// if the address reported by the connection roughly matches their annoucned
-	// listener addresses, its likely to be an external NAT address
-	if HasConsistentTransport(c.RemoteMultiaddr(), lmaddrs) {
-		lmaddrs = append(lmaddrs, c.RemoteMultiaddr())
-	}
+	// NOTE: Do not add `c.RemoteMultiaddr()` to the peerstore if the remote
+	// peer doesn't tell us to do so. Otherwise, we'll advertise it.
 
 	// Extend the TTLs on the known (probably) good addresses.
 	// Taking the lock ensures that we don't concurrently process a disconnect.