Infinite loop ping test for each player

Question

For my Unity game I have a Client-Server model, and I want both sides to ping each other repeatedly to make sure I know what latency between players is. In the server's case, a client connects and their details are logged. Their details are then used when the game creates coroutines. This coroutine starts a loop which pings and waits and pings and waits, etc, until the game ends.

However, it doesn't work. The debug messages are throwing up strange results. It attempts to ping to IP "::ffff:192.168.0.10", and then is waiting forever. I don't suppose the fact I am running this via Unity editor and another app window on the same machine should be an issue? What is the "::ffff" about in the IP it saves when a client connects? Is that the issue? If so, how can I best format it properly?

Yes, I need to add another loop in the coroutine to make it go forever. Once would be a nice start though.

CLIENT CONNECTS TO SERVER

    // Recieve data from all.
    NetworkEventType recData = NetworkTransport.Receive(out socketId, out connectionId, out channelId, buffer, bufferSize, out dataSize, out error);

    switch (recData)
    {
        case NetworkEventType.ConnectEvent:
            if (localConnectionId == connectionId)
            {
                // My active connect request approved.
                Debug.Log("Connection request approved.");
            }
            else // New client.
            {
                string outIp;
                int outPort;
                UnityEngine.Networking.Types.NetworkID outNetwork;
                UnityEngine.Networking.Types.NodeID dstNode;
                byte outError;
                NetworkTransport.GetConnectionInfo(socketId, connectionId, out outIp, out outPort, out outNetwork, out dstNode, out outError);
                AllocateNewLobbyPlayer(socketId, connectionId, channelId, outIp, outPort);
            }
            break;
   }

CREATE PING LOOP COROUTINES

    for (int i = (Game.isServer) ? 1 : 0; i < lobbyPlayers.Length; i++)
    {
        if (lobbyPlayers[i] != null)
        {
            Debug.Log(" STARTED PING FOR " + i);
            StartCoroutine(PingTest(lobbyPlayers[i].ip));
        }
    }

PING LOOP COROUTINE

protected IEnumerator PingTest(string ip)
{
    Ping ping = new Ping(ip);
    Debug.Log(" SENT PING " + ip);
    while (!ping.isDone)
    {
        Debug.Log("WAITING");
        yield return new WaitForFixedUpdate();
    }
    Debug.Log(" PING COMPLETED " + ping.time);
    yield return new WaitForFixedUpdate();
}

DEBUG OUTPUT

 STARTED PING FOR 1
 SENT PING ::ffff:192.168.0.10
 WAITING
 WAITING
 WAITING

etc, etc, etc...

Answer 1

Ping is implemented differently on different platforms.

On some platforms, it's an ICMP Echo Request (the thing that happens when you enter ping [ip-address] in your command shell). These might be blocked by firewalls or routers which do not block the normal game traffic. On others it tries to open a HTTP connection to port 80, which of course doesn't do much if the target IP does not run a webserver.

If what you actually want to do is check the quality of the game connection, you are better off implementing your own Ping message as part of your game's network protocol.

Answer 2

To add to @Philipp answer,

don't forget that there is NetworkTransport.GetCurrentRTT() that allows you to get milliseconds that it takes to travel to destination and back. Notice, you have to be already connected for this to work.