NAT routes should not be mirrored back to the original sender

Signed-off-by: Guvenc Gulce <guevenc.guelce@sap.com>

metalbond.go

@@ -380,17 +380,23 @@ func (m *MetalBond) addSubscriber(peer *metalBondPeer, vni VNI) error {
 	m.log().Infof("Peer %s added Subscription to VNI %d", peer, vni)
 
 	// TODO: we're missing a read-lock on routeTable
-	for dest, hops := range m.routeTable.GetDestinationsByVNI(vni) {
-		for _, hop := range hops {
-			err := peer.SendUpdate(msgUpdate{
-				Action:      ADD,
-				VNI:         vni,
-				Destination: dest,
-				NextHop:     hop,
-			})
-			if err != nil {
-				m.log().Errorf("Could not send UPDATE to peer: %v", err)
-				peer.Reset()
+	for dest, hopToPeersMap := range m.routeTable.GetDestinationsByVNIWithPeer(vni) {
+		for hop, peers := range hopToPeersMap {
+			for _, peerFromList := range peers {
+				// Dont send the NAT routes back to the original peer which announced it
+				if peerFromList == peer && hop.Type == pb.NextHopType_NAT {
+					continue
+				}
+				err := peer.SendUpdate(msgUpdate{
+					Action:      ADD,
+					VNI:         vni,
+					Destination: dest,
+					NextHop:     hop,
+				})
+				if err != nil {
+					m.log().Errorf("Could not send UPDATE to peer: %v", err)
+					peer.Reset()
+				}
 			}
 		}
 	}

routetable.go

@@ -64,6 +64,33 @@ func (rt *routeTable) GetDestinationsByVNI(vni VNI) map[Destination][]NextHop {
 	return ret
 }
 
+func (rt *routeTable) GetDestinationsByVNIWithPeer(vni VNI) map[Destination]map[NextHop][]*metalBondPeer {
+	rt.rwmtx.RLock()
+	defer rt.rwmtx.RUnlock()
+
+	ret := make(map[Destination]map[NextHop][]*metalBondPeer)
+
+	if _, exists := rt.routes[vni]; !exists {
+		return ret
+	}
+
+	for dest, nhm := range rt.routes[vni] {
+		if ret[dest] == nil {
+			ret[dest] = make(map[NextHop][]*metalBondPeer)
+		}
+
+		for nh, peersMap := range nhm {
+			peers := []*metalBondPeer{}
+			for peer := range peersMap {
+				peers = append(peers, peer)
+			}
+			ret[dest][nh] = peers
+		}
+	}
+
+	return ret
+}
+
 func (rt *routeTable) GetNextHopsByDestination(vni VNI, dest Destination) []NextHop {
 	rt.rwmtx.RLock()
 	defer rt.rwmtx.RUnlock()