Networking How should I use local discovery with NetworkTransport?

Hi Philippe
We are creating HLAPI adapter for local discovery feature right now. If by some reason it won't be included in 5.1. It is not very difficult to use HLAPI with local discovery. I will update documentation on this week (I hope ) So with RC you will receive as minimum documents and possible HLAPI solution.

 

Small bad news, discussed with my colleagues yesterday. RC will be open for bug fix only... (it is expected). so there won't direct support of this feature from hlapi. Hence, llapi for this feature is quite straightforward and should be clean.

There is a two roles here: sender and receiver(s).

Sender send Local Discovery (LD) messages to local network (actually to all local subnets which it is connected).
Receiver(s) are waiting on corresponding ports and when they receive LD they will inform about this.

Send message looks like "I'm a peer and I'm able to receive connections on the ip: port"
To do this Sender should call the following function:
bool StartBroadcastDiscovery ( int hostId, int broadcastPort, int key, int version, int subversion, byte[] buffer, int size, int timeout, out byte error )
where
hostId is a id of the host which you want to receive connections: (NetwokConnection.hostId from HLAPI stuff)
broadcastPort it is a port which Sender will send LD messages.
key, version and subversion are 3 values which will be checked by LD receiver, if they are not the same, LD message will be dropped.
buffer, size define message which will be delivered to receiver and will be accessible for user
timeout defines how often these LD messages will send.
So after all information from LD message delivered to end user will contain: ip: port of hostId and buffer[], size message.

To stop spamming network with LD messages sender should call
StopBroadcastDiscovery().

Receivers:
It should call SetBroadcastCredentials() function to set exactly the same key, version, subversion;
It should call AddHost LLAPI function directly and register it on broadcasting port:
int localDiscoveryReceiverId = AddHost(..., broadcastPort ); (llapi func)
It should run ReceiveFromHost() (llapi func) inside unity Update() waiting for BroacastEvent:
And when it receive this event, it can grab connection information
evnt = ReceiveFromHost(localDiscoveryReceiverId, ...)
if(evnt ==BroadcastEvent)
{
GetBroadcastConnectionInfo(.. out ip, out port );
GetBroadcastConnectionMessage( .... byte[] message, out messageLen);
}

It was short description.

 

Here is a script that does local discovery and auto-joins game if it finds a NetworkManager. The IP and port of the host are included in the broadcasted message as data. You can change the function public virtual void OnReceivedBroadcast(string fromAddress, string data) to do something more friendly when a broadcast is received on a client.

Maybe there should be a component like this in HLAPI?

using System;
using UnityEngine;
using UnityEngine.Networking;
using System.Collections;

public class NetworkDiscovery : MonoBehaviour
{
const int kMaxBroadcastMsgSize = 1024;

// config data
[SerializeField]
public int broadcastPort = 47777;

[SerializeField]
public int broadcastKey = 1000;

[SerializeField]
public int broadcastVersion = 1;

[SerializeField]
public int broadcastSubVersion = 1;

[SerializeField]
public string broadcastData = "HELLO";

[SerializeField]
public int offsetX;

[SerializeField]
public int offsetY;

// runtime data
public int hostId = -1;
public bool running = false;
public bool isServer = false;
public bool isClient = false;

byte[] msgOutBuffer = null;
byte[] msgInBuffer = null;

static byte[] GetBytes(string str)
{
byte[] bytes = new byte[str.Length * sizeof(char)];
System.Buffer.BlockCopy(str.ToCharArray(), 0, bytes, 0, bytes.Length);
return bytes;
}

static string GetString(byte[] bytes)
{
char[] chars = new char[bytes.Length / sizeof(char)];
System.Buffer.BlockCopy(bytes, 0, chars, 0, bytes.Length);
return new string(chars);
}

public bool Initialize()
{
if (broadcastData.Length >= kMaxBroadcastMsgSize)
{
Debug.LogError("NetworkDiscovery Initialize - data too large. max is " + kMaxBroadcastMsgSize);
return false;
}

if (!NetworkTransport.IsStarted)
{
NetworkTransport.Init();
}


if (NetworkManager.singleton != null)
{
broadcastData = "NetworkManager:"+NetworkManager.singleton.networkAddress + ":" + NetworkManager.singleton.networkPort;
}

DontDestroyOnLoad(gameObject);
msgOutBuffer = GetBytes(broadcastData);
msgInBuffer = new byte[kMaxBroadcastMsgSize];
return true;
}

// listen for broadcasts
public bool StartAsClient()
{
if (hostId != -1 || running)
{
Debug.LogWarning("NetworkDiscovery StartAsClient already started");
return false;
}

ConnectionConfig cc = new ConnectionConfig();
cc.AddChannel(QosType.Unreliable);
HostTopology defaultTopology = new HostTopology(cc, 1);

hostId = NetworkTransport.AddHost(defaultTopology, broadcastPort);
if (hostId == -1)
{
Debug.LogError("NetworkDiscovery StartAsClient - addHost failed");
return false;
}

byte error;
NetworkTransport.SetBroadcastCredentials(hostId, broadcastKey, broadcastVersion, broadcastSubVersion, out error);

running = true;
isClient = true;
Debug.Log("StartAsClient Discovery listening");
return true;
}

// perform actual broadcasts
public bool StartAsServer()
{
if (hostId != -1 ||running)
{
Debug.LogWarning("NetworkDiscovery StartAsServer already started");
return false;
}

ConnectionConfig cc = new ConnectionConfig();
cc.AddChannel(QosType.Unreliable);
HostTopology defaultTopology = new HostTopology(cc, 1);

hostId = NetworkTransport.AddHost(defaultTopology, 0);
if (hostId == -1)
{
Debug.LogError("NetworkDiscovery StartAsServer - addHost failed");
return false;
}

byte err;
if (!NetworkTransport.StartBroadcastDiscovery(hostId, broadcastPort, broadcastKey, broadcastVersion, broadcastSubVersion, msgOutBuffer, msgOutBuffer.Length, 1000, out err))
{
Debug.LogError("NetworkDiscovery StartBroadcast failed err: " + err);
return false;
}

running = true;
isServer = true;
Debug.Log("StartAsServer Discovery broadcasting");
return true;
}

public void StopBroadcast()
{
if (hostId == -1)
{
Debug.LogError("NetworkDiscovery StopBroadcast not initialized");
return;
}

if (!running)
{
Debug.LogWarning("NetworkDiscovery StopBroadcast not started");
return;
}
if (isServer)
{
NetworkTransport.StopBroadcastDiscovery();
}

NetworkTransport.RemoveHost(hostId);
hostId = -1;
running = false;
isServer = false;
isClient = false;
Debug.Log("Stopped Discovery broadcasting");
}

void Update()
{
if (hostId == -1)
return;

if (isServer)
return;

int connectionId;
int channelId;
int receivedSize;
byte error;
NetworkEventType networkEvent = NetworkEventType.DataEvent;

do
{
networkEvent = NetworkTransport.ReceiveFromHost(hostId, out connectionId, out channelId, msgInBuffer, kMaxBroadcastMsgSize, out receivedSize, out error);

if (networkEvent == NetworkEventType.BroadcastEvent)
{
NetworkTransport.GetBroadcastConnectionMessage(hostId, msgInBuffer, kMaxBroadcastMsgSize, out receivedSize, out error);

string senderAddr;
int senderPort;
NetworkTransport.GetBroadcastConnectionInfo(hostId, out senderAddr, out senderPort, out error);

OnReceivedBroadcast(senderAddr, GetString(msgInBuffer));
}
} while (networkEvent != NetworkEventType.Nothing);

}

public virtual void OnReceivedBroadcast(string fromAddress, string data)
{
Debug.Log("Got broadcast from [" + fromAddress + "] " + data);
var items = data.Split(':');
if (items.Length == 3 && items[0] == "NetworkManager")
{
if (NetworkManager.singleton != null && NetworkManager.singleton.client == null)
{
NetworkManager.singleton.networkAddress = items[1];
NetworkManager.singleton.networkPort = Convert.ToInt32(items[2]);
NetworkManager.singleton.StartClient();
}
}

}

void OnGUI()
{
int xpos = 10 + offsetX;
int ypos = 40 + offsetY;
int spacing = 24;

if (msgInBuffer == null)
{
if (GUI.Button(new Rect(xpos, ypos, 200, 20), "Initialize Broadcast"))
{
Initialize();
}
return;
}
else
{
GUI.Label(new Rect(xpos, ypos, 200, 20), "initialized");
}
ypos += spacing;

if (running)
{
if (GUI.Button(new Rect(xpos, ypos, 200, 20), "Stop"))
{
StopBroadcast();
}
ypos += spacing;
}
else
{
if (GUI.Button(new Rect(xpos, ypos, 200, 20), "Start Broadcasting"))
{
StartAsServer();
}
ypos += spacing;

if (GUI.Button(new Rect(xpos, ypos, 200, 20), "Listen for Broadcast"))
{
StartAsClient();
}
ypos += spacing;
}
}
}

 

Maybe it is a configuration issue. Here is a simple project with the components setup

 

Hi, could you paste ifconfig information here? Was it localdiscovery between two different computers? If yes, paste please ifconfig info from both machines.