test: fix peer reflexive connectivity (#116)

client/internal/connection.go

@@ -188,11 +188,19 @@ func (conn *Connection) Open(timeout time.Duration) error {
 		}
 		// in case the remote peer is in the local network or one of the peers has public static IP -> no need for a Wireguard proxy, direct communication is possible.
 		if !useProxy(pair) {
-			log.Debugf("it is possible to establish a direct connection (without proxy) to peer %s - my addr: %s, remote addr: %s", conn.Config.RemoteWgKey.String(), pair.Local.Address(), pair.Remote.Address())
-			err = conn.wgProxy.StartLocal(fmt.Sprintf("%s:%d", pair.Remote.Address(), iface.WgPort))
+			log.Debugf("it is possible to establish a direct connection (without proxy) to peer %s - my addr: %s, remote addr: %s", conn.Config.RemoteWgKey.String(), pair.Local, pair.Remote)
+			var endpoint string
+			if isPublicIP(net.ParseIP(pair.Local.Address())) {
+				//skip endpoint because we are public - it will be discovered by Wireguard automatically
+				endpoint = ""
+			} else {
+				endpoint = fmt.Sprintf("%s:%d", pair.Remote.Address(), iface.WgPort)
+			}
+			err = conn.wgProxy.StartLocal(endpoint)
 			if err != nil {
 				return err
 			}
+
 		} else {
 			log.Infof("establishing secure tunnel to peer %s via selected candidate pair %s", conn.Config.RemoteWgKey.String(), pair)
 			err = conn.wgProxy.Start(remoteConn)
@@ -239,23 +247,31 @@ func isPublicIP(ip net.IP) bool {
 }
 
 //useProxy determines whether a direct connection (without a go proxy) is possible
-//There are 2 cases: one of the peers has a public IP or both peers are in teh same private network.
+//There are 3 cases: one of the peers has a public IP or both peers are in the same private network
 //Please note, that this check happens when peers were already able to ping each other with ICE layer.
 func useProxy(pair *ice.CandidatePair) bool {
 	remoteIP := net.ParseIP(pair.Remote.Address())
 	myIp := net.ParseIP(pair.Local.Address())
+	remoteIsPublic := isPublicIP(remoteIP)
+	myIsPublic := isPublicIP(myIp)
 	if pair.Local.Type() == ice.CandidateTypeHost && pair.Remote.Type() == ice.CandidateTypeHost {
-		if isPublicIP(remoteIP) || isPublicIP(myIp) {
+		if remoteIsPublic || myIsPublic {
 			//one of the hosts has a public IP
 			return false
 		}
 
-		if !isPublicIP(remoteIP) && !isPublicIP(myIp) {
+		if !remoteIsPublic && !myIsPublic {
 			//both hosts are in the same private network
 			return false
 		}
 	}
 
+	if (pair.Local.Type() == ice.CandidateTypeHost && myIsPublic) && pair.Remote.Type() == ice.CandidateTypePeerReflexive {
+		// same as the case when either host is public but adds additional case when remote is peer reflexive
+		// remote is peer reflexive and we are public -> no proxy needed
+		return false
+	}
+
 	return true
 }