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Listen to message from an IP from another machine

I am trying to send a message to Unity through UDP. The machine that sends the message has IP as 192.16.14.1 and port as 3034. How do I enter these two inside of Unity application? I have found a code to listen for UDP messages but I cannot set the IP address here. Also the Unity application should be running at all times even if the message from another machine is sent or not.
using System.Collections;
using System.Collections.Generic;
using System.Net;
using System.Net.Sockets;
using UnityEngine;
public class UDP_Listen : MonoBehaviour
{
UdpClient clientData;
int portData = 3034;
public int receiveBufferSize = 120000;
public bool showDebug = false;
IPEndPoint ipEndPointData;
private object obj = null;
private System.AsyncCallback AC;
byte[] receivedBytes;
void Start()
{
InitializeUDPListener();
}
public void InitializeUDPListener()
{
ipEndPointData = new IPEndPoint(IPAddress.Any, portData);
clientData = new UdpClient();
clientData.Client.ReceiveBufferSize = receiveBufferSize;
clientData.Client.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, optionValue: true);
clientData.ExclusiveAddressUse = false;
clientData.EnableBroadcast = true;
clientData.Client.Bind(ipEndPointData);
clientData.DontFragment = true;
if (showDebug) Debug.Log("BufSize: " + clientData.Client.ReceiveBufferSize);
AC = new System.AsyncCallback(ReceivedUDPPacket);
clientData.BeginReceive(AC, obj);
Debug.Log("UDP - Start Receiving..");
}
void ReceivedUDPPacket(System.IAsyncResult result)
{
//stopwatch.Start();
receivedBytes = clientData.EndReceive(result, ref ipEndPointData);
ParsePacket();
clientData.BeginReceive(AC, obj);
//stopwatch.Stop();
//Debug.Log(stopwatch.ElapsedTicks);
//stopwatch.Reset();
} // ReceiveCallBack
void ParsePacket()
{
// work with receivedBytes
Debug.Log("receivedBytes len = " + receivedBytes.Length);
}
void OnDestroy()
{
if (clientData != null)
{
clientData.Close();
}
}
}

If the Unity application is to be receiving the messages constantly, it needs to be something like:
UdpClient listener = new UdpClient(11000);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Parse("192.16.14.1"), 3034);
while (true)
{
byte[] bytes = listener.Receive(ref groupEP);
}
This should read only calls from the specific IP, not sure which port you want the UDPClient to read out from (specified in the UDPClient constructor) but you can set this to whatever you need it to be.

So there are two different things:
You want to define the receiving local port you Bind your socket to
You want to define the expected sending remote ip + port you want to Receive from
Currently you are using the very same one
ipEndPointData = new IPEndPoint(IPAddress.Any, portData);
for both! (Fun fact: As a side effect by using always the same field you basically allow any sender but are then bond to that specific sender from this moment on)
Actually a lot of things you configure there are the default values anyway so here is more or less what I would do
using System;
using System.Collections.Concurrent;
using System.Net;
using System.Net.Sockets;
using System.Threading;
using UnityEngine;
public class UDP_Listen : MonoBehaviour
{
public ushort localReceiverPort = 3034;
public string senderIP = "192.168.111.1";
public ushort remoteSenderPort = 3034;
public bool showDebug = false;
// Thread-safe Queue to handle enqueued actions in the Unity main thread
private readonly ConcurrentQueue<Action> mainThreadActions = new ConcurrentQueue<Action>();
private Thread udpListenerThread;
private void Start()
{
// do your things completely asynchronous in a background thread
udpListenerThread = new Thread(UDPListenerThread);
udpListenerThread.Start();
}
private void Update()
{
// in the Unity main thread work off the actions
while (mainThreadActions.TryDequeue(out var action))
{
action?.Invoke();
}
}
private void UDPListenerThread()
{
UdpClient udpClient = null;
try
{
// local end point listens on any local IP
var localEndpoint = new IPEndPoint(IPAddress.Any, localReceiverPort);
udpClient = new UdpClient(localEndpoint);
if (showDebug)
{
Debug.Log("BufSize: " + clientData.Client.ReceiveBufferSize);
}
Debug.Log("UDP - Start Receiving..");
// endless loop -> ok since in a thread and containing blocking call(s)
while (true)
{
// remote sender endpoint -> listens only to specific IP
var expectedSenderEndpoint = new IPEndPoint(IPAddress.Parse(senderIP), remoteSenderPort);
// blocking call - but doesn't matter since this is a thread
var receivedBytes = udpClient.Receive(ref expectedSenderEndpoint);
// parse the bytes here
// do any expensive work while still on a background thread
mainThreadActions.Enqueue(() =>
{
// Put anything in here that is required to happen in the Unity main thread
// so basically anything using GameObject, Transform, etc
});
}
}
// thrown for "Abort"
catch (ThreadAbortException)
{
Debug.Log("UDP Listener terminated");
}
// Catch but Log any other exception
catch (Exception e)
{
Debug.LogException(e);
}
// This is run even if an exception happend
finally
{
// either way dispose the UDP client
udpClient?.Dispose();
}
}
private void OnDestroy()
{
udpListenerThread?.Abort();
}
}
I'm sure the same can be done also using the BeginReceive/EndReceive or task based alternatives but since it is going to run endless anyway I personally find a thread often easier to read and maintain.

I think you got it backwards. This code you shared is for, like you said, listen UDP protocol on desired port. This piece of code needs to be inside your "server". By server try to understand that as the receiving side.
on your shared method InitializeUDPListener(); we have this piece:
ipEndPointData = new IPEndPoint(IPAddress.Any, portData);
this means you are initializing your udp socket to listen for ANY ip adresses at the given port. That said, you have your server ready to go, what you need to do is setup the client side, the one who sends the message.
here some example:
public string serverIp = "127.0.0.1"; // your server ip, this one is sending to local host
public int serverPort = 28500; // your server port
public void ClientSendMessage()
{
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
IPAddress broadcast = IPAddress.Parse(serverIp);
byte[] sendbuf = Encoding.ASCII.GetBytes("THIS IS A MESSAGE FROM CLIENT!");
IPEndPoint ep = new IPEndPoint(broadcast, serverPort);
s.SendTo(sendbuf, ep);
}
I encourage you to read about UDP/TCP protocols before using them. MS has documentation with details.
here some links:
TCP
UDP
Sockets

C# - Can't receive UDP on second computer

I can send UDP messages from one computer to itself on a certain port but I can't send this messages from one computer to another in the same lan. I am pretty new to C# and I am also new to network programming so the solution is probably easy...
I have tried an example from Microsoft Docs and did only small changes. (names, etc.)
Both codes run as seperate programs.
//RECEIVE
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
public class UDPListener
{
private const int listenPort = 11000;
private static void Listen()
{
UdpClient listener = new UdpClient(listenPort);
IPEndPoint groupEP = new IPEndPoint(IPAddress.Any, listenPort);
try
{
while (true)
{
Console.WriteLine("Waiting for broadcast");
byte[] receivebytes = listener.Receive(ref groupEP);
Console.WriteLine(Encoding.ASCII.GetString(receivebytes, 0, receivebytes.Length));
}
}
catch (SocketException e)
{
Console.WriteLine(e);
}
finally
{
listener.Close();
}
}
public static void Main()
{
Listen();
}
}
//SEND
using System;
using System.Net;
using System.Net.Sockets;
using System.Text;
class Program
{
static void Main(string[] args)
{
Socket socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
//192.168.2.5 is the IP Address of the receiving computer
IPAddress broadcast = IPAddress.Parse("192.168.2.5");
byte[] bytestosend = Encoding.ASCII.GetBytes("Hi");
IPEndPoint ep = new IPEndPoint(broadcast, 11000);
socket.SendTo(bytestosend, ep);
Console.WriteLine("bytestosend were send");
}
}
The sending program tells me that the message was sent but the receiving program gives no output.
EDIT 1: The Ressource Manager said that on the receiving computer was no network activity while on the sending computer is actually sending something.
EDIT 2: I tried my applications in an other network and it worked fine. I did some research and I found that sometimes routers don't allow udp broadcasts through a subnet (or anything similar...). So I assume it might be my router. (unfortunately I can not access it's settings.) So I think the problem has resolved itself!

Why do I need two sockets in server application?

I am trying to learn socket programming in C#
By using google I found a lot of good tutorials and examples.
But here is my own code :
Sender application :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net; // socket library
using System.Net.Sockets; // socket library
namespace Sender
{
class Program
{
static void Main(string[] args)
{
Console.Write("Enter remote IP : ");
IPAddress ipAddress = IPAddress.Parse(Console.ReadLine());
Socket sender = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
sender.Connect(ipAddress, 4444);
Console.Write("Enter text to send : ");
byte[] message = Encoding.ASCII.GetBytes(Console.ReadLine().ToString());
sender.Send(message);
sender.Shutdown(SocketShutdown.Both);
sender.Close();
Console.ReadKey();
} // main
} // main
} // main
Receiver application :
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net; // socket library
using System.Net.Sockets; // socket library
namespace Listener
{
class Program
{
static void Main(string[] args)
{
IPAddress ipAddress = Dns.GetHostAddresses(Dns.GetHostName()).Where(address => address.AddressFamily == AddressFamily.InterNetwork).First();
Console.WriteLine("Listening on " + ipAddress.ToString() + " : 4444");
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, 4444);
Socket listener = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
listener.Bind(localEndPoint);
listener.Listen(10);
Socket handler = listener.Accept();
byte[] bytes = new Byte[1024];
int bytesRec = handler.Receive(bytes);
Console.WriteLine(Encoding.ASCII.GetString(bytes, 0, bytesRec));
handler.Shutdown(SocketShutdown.Both);
handler.Close();
listener.Close();
Console.ReadKey();
} // main
} // main
} // main
The code works fine, but I want to know why do I need two sockets in server side? The first one is listener and the second one is handler. Is it possible to omit one of them so that the code become more simple?
By the way my code is based on these codes :
Synchronous Client Socket Example : https://learn.microsoft.com/en-us/dotnet/framework/network-programming/synchronous-client-socket-example
Synchronous Server Socket Example : https://learn.microsoft.com/en-us/dotnet/framework/network-programming/synchronous-server-socket-example
Also I am using Microsoft Visual C# 2008 Express Edition

The listener socket is listening for the incoming connections. If there were no handler socket, then there were no one to listen for parallel incoming connections until the communication with the client is over.
That's why Accept returns another socket, which is used for communication, and the listening socket continues waiting for incoming connections.
You can see it as a kind of weakly-typed objects: the Socket is responsible for both listening and communication roles, although it might be better to have different types for these two different tasks. But this behaviour reflects the traditional socket behaviour, so it remains as it is in order to be familiar to the people having background in network programming.
The more high-level API (TcpListener and TcpClient) makes a clear distinction between listening and communication roles.

Verifying delivery of TCP messages

I'm writing an application to send syslogs to a central server. The network connection to the server is expected to be unreliable. For this reason, I need to be able to check whether the messages have been received by the server, so that if the send is unsuccessful I can try sending them again later.
I have no control over the server, only the ability to form a TCP connection with it - most questions I've seen recommend writing custom ACK logic, but that's not an option for me. I need an entirely client-side approach. Is there any way I can access the TCP acknowledgements in order to mark a message as sent?

The TCP protocol guarantees that the data is properly delivered at the remote server. To quote from the original TCP specification in RFC 793:
An acknowledgment by TCP does not guarantee that the data has been
delivered to the end user, but only that the receiving TCP has taken
the responsibility to do so.
So if you do not get an error from your sending part, you have a confirm that the remove server TCP stack has properly received your data. TCP has built-in detection for damaged, lost, duplicated, or out of order delivered packets (using sequence numbers) and will retransmit packets when it detects problems.

As the other poster has mentioned, TCP is a reliable protocol. You can wrap this in some exception handling code to ensure that messages are re-sent when the connection is restored, for example:
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Net;
using System.Net.Sockets;
namespace TCPClientTest
{
class SyslogMessage
{
public Guid Guid = Guid.NewGuid();
public byte[] MessageData;
}
class Program
{
static readonly int TCP_PORT = 1337;
static byte[] SendTCPMessage(String hostname, int port, byte[] data)
{
using (var client = new TcpClient(hostname, port))
{
using (var stream = client.GetStream())
{
stream.Write(data, 0, data.Length);
var responseData = new byte[1024];
var byteCount = stream.Read(responseData, 0, responseData.Length);
return responseData.Take(byteCount).ToArray();
}
}
}
static void SendSyslog(String hostname, int port, SyslogMessage m)
{
SendTCPMessage(hostname, port, m.MessageData);
}
static Queue<SyslogMessage> sysLogQueue = new Queue<SyslogMessage>(new List<SyslogMessage>()
{
new SyslogMessage() { MessageData = Encoding.UTF8.GetBytes("Test data 1")},
new SyslogMessage() { MessageData = Encoding.UTF8.GetBytes("Test data 2")}
});
static void Main(string[] args)
{
System.Threading.Timer timer = new System.Threading.Timer(SendLogs, null, 1000, 5000);
Console.WriteLine("Press return to continue...");
Console.Read();
}
static void SendLogs(object state)
{
while (sysLogQueue.Count > 0)
{
try
{
var m = sysLogQueue.Peek();
SendSyslog("localhost", TCP_PORT, m);
Console.WriteLine("Sent sys log: " + Encoding.UTF8.GetString(m.MessageData));
// Remove from queue.
sysLogQueue.Dequeue();
}
catch (SocketException e)
{
// Leave in the queue.
Console.WriteLine("Failed to send log: Socket exception occurred: {0}", e);
// Break until next attempt.
break;
}
}
}
}
}
I've used port 1337 for this, just set this to whatever you need.

Winsock server/client application in c#

I'm working to make a Client/Server Application in C# using winsock Control. I done every thing in that but i stuck the place of sending data from client to server. In my program server always listen the client using the ip and port. I send the data from the client to server.
1)When click the Listen button on the server form it open the server where client is connect.
2)In Client form 1st i click the connect button for that the server is connected Gives an message (Connect Event: ip) for this message we easly know that the client is connected to the server.
3)Then we enter some data in the Send Data text Box then click Send Button to send the data to server and also save in client.
Code Below:
SERVER:
using System;
using System.Collections.Generic;
using System.Windows.Forms;
using System.Net;
using System.Threading;
using System.Net.Sockets;
namespace Server
{
public partial class Form1 : Form
{
public Form1()
{
InitializeComponent();
}
const string DEFAULT_SERVER = "ip";
const int DEFAULT_PORT = 120;
System.Net.Sockets.Socket serverSocket;
System.Net.Sockets.SocketInformation serverSocketInfo;
public string Startup()
{
IPHostEntry hostInfo = Dns.GetHostByName(DEFAULT_SERVER);
IPAddress serverAddr = hostInfo.AddressList[0];
var serverEndPoint = new IPEndPoint(serverAddr, DEFAULT_PORT);
serverSocket = new System.Net.Sockets.Socket(System.Net.Sockets.AddressFamily.InterNetwork, System.Net.Sockets.SocketType.Stream, System.Net.Sockets.ProtocolType.Tcp);
serverSocket.Bind(serverEndPoint);
return serverSocket.LocalEndPoint.ToString();
}
public string Listen()
{
int backlog = 0;
try
{
serverSocket.Listen(backlog);
return "Server listening";
}
catch (Exception ex)
{
return "Failed to listen" + ex.ToString();
}
}
public string ReceiveData()
{
System.Net.Sockets.Socket receiveSocket;
byte[] buffer = new byte[256];
receiveSocket = serverSocket.Accept();
var bytesrecd = receiveSocket.Receive(buffer);
receiveSocket.Close();
System.Text.Encoding encoding = System.Text.Encoding.UTF8;
return encoding.GetString(buffer);
}
private void Listen_Click(object sender, EventArgs e)
{
string serverInfo = Startup();
textBox1.Text = "Server started at:" + serverInfo;
serverInfo = Listen();
textBox1.Text = serverInfo;
//string datatosend = Console.ReadLine();
//SendData(datatosend);
serverInfo = ReceiveData();
textBox1.Text = serverInfo;
//Console.ReadLine();
}
private void winsock_DataArrival(object sender, AxMSWinsockLib.DMSWinsockControlEvents_DataArrivalEvent e)
{
ReceiveData();
Listen();
}
private void winsock_ConnectEvent(object sender, EventArgs e)
{
Listen();
}
}
}
This all are work perfectly But here my problem is that i get data form the client to server at only one time. When i send data again from the client to the server its not working and gives me some Message like
Additional information: Only one usage of each socket address
(protocol/network address/port) is normally permitted
In the server form
serverSocket.Bind(serverEndPoint);
Please someone help me to solve my problem.
Thank you.

Try this. It helps you
delegate void AddTextCallback(string text);
public Form1()
{
InitializeComponent();
}
private void ButtonConnected_Click(object sender, EventArgs e)
{
ThreadPool.QueueUserWorkItem(new WaitCallback(ServerHandler));
}
private void ServerHandler(object state)
{
TcpListener _listner = new TcpListener(IPAddress.Parse("12.2.54.658"), 145);
_listner.Start();
AddText("Server started - Listening on port 145");
Socket _sock = _listner.AcceptSocket();
//AddText("User from IP " + _sock.RemoteEndPoint);
while (_sock.Connected)
{
byte[] _Buffer = new byte[1024];
int _DataReceived = _sock.Receive(_Buffer);
if (_DataReceived == 0)
{
break;
}
AddText("Message Received...");
string _Message = Encoding.ASCII.GetString(_Buffer);
AddText(_Message);
}
_sock.Close();
AddText("Client Disconnected.");
_listner.Stop();
AddText("Server Stop.");
}
private void AddText(string text)
{
if (this.listBox1.InvokeRequired)
{
AddTextCallback d = new AddTextCallback(AddText);
this.Invoke(d, new object[] { text });
}
else
{
this.listBox1.Items.Add(text);
}
}
I'm also have the same problem like you on last month but i solve that using this Receive multiple different messages TcpListener C# from stackoverflow. This helps me lot hope it helps to solve your problem also.

I'm not 100% sure you understand TCP sockets so here goes.
When you use a TCP listener socket you first bind to a port so that clients have a fixed, known point to connect to. This reserves the port for your socket until you give it up by calling Close() on that socket.
Next you Listen in order to begin the process of accepting clients on the port you bound to. You can do both this and the first step in one but as you haven't I haven't here.
Next you call Accept(). This blocks (halts execution) until a client connects and then it returns a socket which is dedicated to communication with that client. If you want to allow another client to connect, you have to call Accept() again.
You can then communicate with your client using the socket that was returned by Accept() until you're done, at which point you call Close() on that socket.
When you're done listening for new connections you call Close() on your listener socket.
However when you press your listen button the following happens:
You bind correctly, you begin listening correctly and then your call to ReceiveData() blocks on the Accept call until a client is received. You then receive some data (though this is TCP so that might not be the whole data!) and then you instantly close the connection to your client.
I presume to get the error you're getting you must then press listen again on your server. This therefore restarts the whole listener socket and when you get to bind to the port the second time your previous listener is still bound to it and thus the call fails because something's already allocated on that port.
Solution wise you need to keep the socket returned from the Accept() call open until you're done with it. Have the client handle the close by calling the Shutdown() method on their socket or establish some convention for marking the end of communication.
You're also going to run into trouble when you try and have multiple users connected and so at some point you're either going to require threads or some asynchronous sockets but I feel that's out the scope of this question.

I suggest you do not use AxMSWinsockLib.. Have a look at socket example given here where it shows how to create a client socket and server socket - https://msdn.microsoft.com/en-us/library/kb5kfec7(v=vs.110).aspx AND this one - https://msdn.microsoft.com/en-us/library/6y0e13d3(v=vs.110).aspx