I try to send message to all members of the group. Sender:
// Create socket
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
// Multicast IP-address
IPAddress ip = IPAddress.Parse("224.168.55.25");
// Join multicast group
s.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(ip));
// TTL
s.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 2);
// Create an endpoint
IPEndPoint ipep = new IPEndPoint(ip, 4567);
// Connect to the endpoint
s.Connect(ipep);
// Scan message
while (true)
{
byte[] buffer = new byte[1024];
string msg = Console.ReadLine();
buffer = Encoding.ASCII.GetBytes(msg);
s.Send(buffer, buffer.Length, SocketFlags.None);
if (msg.Equals("Bye!", StringComparison.Ordinal))
break;
}
// Close socket
s.Close();
Receiver:
// Create new socket
Socket s = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
// Create IP endpoint
IPEndPoint ipep = new IPEndPoint(IPAddress.Any, 4567);
// Bind endpoint to the socket
s.Bind(ipep);
// Multicast IP-address
IPAddress ip = IPAddress.Parse("224.168.55.25");
// Add socket to the multicast group
s.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(ip, IPAddress.Any));
// Receive messages
while (true)
{
byte[] data = new byte[1024];
s.Receive(data);
string str = System.Text.Encoding.ASCII.GetString(data, 0, data.Length);
Console.WriteLine(str.Trim());
if (str.Equals("Bye!", StringComparison.Ordinal))
{
break;
}
}
I don't uderstand why there is a lot of free space between messages when I print them to screen on the client side? Why loop in the Receiver program doesn't stop after receiveing message Bye!? How can I fix this problems?
Thank you very much!
You are creating a udp socket. Udp sockets are not connection oriented. So it just receives messages and has no idea about the state of the sender. Even if the sender socket closes, the receiver would keep on listening.
I hope I have understood your question correctly.
if (strData.Trim().Equals("Bye!", StringComparison.Ordinal))
{
Console.WriteLine("that's right");
break;
}
Socket.Receive() return the bytes received you should use the return value to generate the string, or you will get a string with the length of 1024 and Trim cannot handle it.
int len = s.Receive(data);
string str = System.Text.Encoding.ASCII.GetString(data, 0, len);
Related
I´m trying to make a Windows Service which waits a conexion but not in a determinate port. It has to wait a conexion and then, get the port which the sender is trying to connect. The check if the port is free is done by me in the Sender part.
Listener:
Here is where I need help. I need to do something to don´t need a port to inicializate the conexion.
{
// Get Host IP Address that is used to establish a connection
// In this case, we get one IP address of localhost that is IP : 127.0.0.1
// If a host has multiple addresses, you will get a list of addresses
IPHostEntry host = Dns.GetHostEntry("localhost");
IPAddress ipAddress = host.AddressList[0];
IPEndPoint localEndPoint = new IPEndPoint(ipAddress, port);
try
{
// Create a Socket that will use Tcp protocol
Socket listener = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
// A Socket must be associated with an endpoint using the Bind method
listener.Bind(localEndPoint);
// Specify how many requests a Socket can listen before it gives Server busy response.
// We will listen 10 requests at a time
listener.Listen(10);
Console.WriteLine("Waiting for a connection...");
Socket handler = listener.Accept();
// Incoming data from the client.
string data = null;
byte[] bytes = null;
while (true)
{
bytes = new byte[1024];
int bytesRec = handler.Receive(bytes);
//_installerProcess = (Process) BinarySerialization.Deserializate(bytes);
//Console.WriteLine("Proceso recibido");
data += Encoding.ASCII.GetString(bytes, 0, bytesRec);
if (data.IndexOf("<EOF>") > -1)
{
break;
}
break;
}
{...}
Sender:
Here is where i check te port and where I send the data.
public static void StartClient(String toSend)
{
byte[] bytes = new byte[1024];
try
{
// Connect to a Remote server
// Get Host IP Address that is used to establish a connection
// In this case, we get one IP address of localhost that is IP : 127.0.0.1
// If a host has multiple addresses, you will get a list of addresses
IPHostEntry host = Dns.GetHostEntry("localhost");
IPAddress ipAddress = host.AddressList[0];
IPEndPoint remoteEP = new IPEndPoint(ipAddress, FreeTcpPort() );
// Create a TCP/IP socket.
Socket sender = new Socket(ipAddress.AddressFamily, SocketType.Stream, ProtocolType.Tcp);
// Connect the socket to the remote endpoint. Catch any errors.
try
{
// Connect to Remote EndPoint
sender.Connect(remoteEP);
Console.WriteLine("Socket connected to {0}",
sender.RemoteEndPoint.ToString());
// Encode the data string into a byte array.
byte[] msg = Encoding.ASCII.GetBytes(toSend);
// Send the data through the socket.
int bytesSent = sender.Send(msg);
// Receive the response from the remote device.
int bytesRec = sender.Receive(bytes);
Console.WriteLine("Echoed test = {0}",
Encoding.ASCII.GetString(bytes, 0, bytesRec));
{...}
}
static int FreeTcpPort()
{
TcpListener l = new TcpListener(IPAddress.Loopback, 0);
l.Start();
int port = ((IPEndPoint)l.LocalEndpoint).Port;
l.Stop();
return port;
}
In my adaption of a few multicast tutorials, I changed my method of sending packets.
In my case, I create a queue of packets of size bytes[1024], after which it is sent via Socket.Send() over all online network adapters
Problem:
When sending, another method called receiveMessage() is running on a separate thread. Using Socket.Bind(), it captures packets, but only 1 packet is captured.
Am I doing too much processing thus delaying (and losing) the packets received?
UPDATE
I am considering adding a queue for incoming packets, thus 1 threads captures and stores, the second processes the packets.
SendMethod
Socket _listener_socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
foreach (IPAddress localIP in Dns.GetHostAddresses(Dns.GetHostName()).Where(i => i.AddressFamily == AddressFamily.InterNetwork))
{
//handle image and files
_listener_socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(_MultiIP, localIP));
_listener_socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.MulticastTimeToLive, 1);
_listener_socket.SetSocketOption(SocketOptionLevel.Socket, SocketOptionName.ReuseAddress, true);
_listener_socket.MulticastLoopback = true;
_listener_socket.Connect(new IPEndPoint(_MultiIP, _PORT));
int count = MSGS_TO_SEND.Count;
while (count > 0)
{
count--;
byte[] temp = (byte[])(MSGS_TO_SEND.Dequeue());
_listener_socket.Send(temp, _BYTE_BUFFER_SIZE, SocketFlags.None);
MSGS_TO_SEND.Enqueue(temp);
}
//----------------------------------------------
//-------------------SEND DATA------------------
//----------------------------------------------
}
_listener_socket.Close();
Receive method
//initialise multicast group and bind to interface
Socket _sender_socket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
IPEndPoint ipep = new IPEndPoint(IPAddress.Any, _PORT);
_sender_socket.Bind(ipep);
IPAddress localip = _MultiIP;
_sender_socket.SetSocketOption(SocketOptionLevel.IP, SocketOptionName.AddMembership, new MulticastOption(localip, IPAddress.Any));
//{
while (_sender_socket.IsBound && !bStop)
{
byte[] b = new byte[_BYTE_BUFFER_SIZE];
_sender_socket.Receive(b);
char[] chars = new char[_BYTE_BUFFER_SIZE];
System.Buffer.BlockCopy(b, 0, chars, 0, b.Length);
string _message = new string(chars).Trim();
string ip = _message.Substring(0, _message.IndexOf("~"));
_message = _message.Remove(0, _message.IndexOf("~") + 1);
string _flag = _message.Substring(0, _message.IndexOf("~"));
_message = _message.Remove(0, _message.IndexOf("~") + 1);
_message = _message.Replace("\0", string.Empty);
ip = "1.0";
icount++;
handleData(ip, _flag, _message);
}
If you wan't to try, here is a fully working example: https://github.com/efaruk/playground/tree/master/Multicasting
You can use those re-usable components (MulticastSender, MulticastReceiver,) in your project if you whish...
The sender doesn't have to bind or add membership. Any datagram socket can send to a multicast address. The receiver needs to add membership to the multicast address. The sender and receiver also need to agree upon the port (receiver should be bound to the port.)
Your Multicast Options in each example have the arguments reversed.
The sockets already have buffering from the kernel, so you don't need to complicate your code with message queues.
I've tried multiple methods of doing this, and non seem to work out. But there must be a way.
What I'm trying to do (in C#) is create a server. I want the server to listen on a IP and port, and when it connects to a client, I want it to read what the client says, and send a reply. For the client, I want to connect to a server and send data, and receive the reply from the server.
How can I go about doing this?
I've used Microsoft examples and examples found on MSDN. They have Client > data > Server but it doesn't ever seem to include the server reply.
I know this can be done, obviously, because we have multiplayer games.
Thanks for the help.
EDIT - Code snippets
SERVER
static void Main(string[] args)
{
int recv;
byte[] data = new byte[1024];
IPEndPoint endPoint = new IPEndPoint(IPAddress.Any, 904);
Socket newSocket = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
newSocket.Bind(endPoint);
Console.WriteLine("Listening for connections...");
//LISTEN FOR CLIENT
IPEndPoint sender = new IPEndPoint(IPAddress.Any, 904);
EndPoint tmpRemote = (EndPoint)sender;
//READ MESSAGE FROM CLIENT
recv = newSocket.ReceiveFrom(data, ref tmpRemote);
Console.WriteLine("Messaged received from: " + tmpRemote.ToString());
Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
string welcome = "Welcome to server!";
data = Encoding.ASCII.GetBytes(welcome);
//SEND WELCOME REPLY TO CLIENT
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
sock.Bind(tmpRemote);
sock.SendTo(data, tmpRemote);
Console.WriteLine("Reply sent to client");
while (true)
{
if(!newSocket.Connected)
{
Console.WriteLine("Client disconnected.");
break;
}
data = new byte[1024];
recv = newSocket.ReceiveFrom(data, ref tmpRemote);
if (recv == 0)
break;
Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
}
newSocket.Close();
Console.WriteLine("Server disconnected.");
Console.ReadLine();
}
}
CLIENT
static void Main(string[] args)
{
Console.WriteLine("Message [127.0.0.1:904]: ");
string msg = Console.ReadLine();
byte[] packetData = ASCIIEncoding.ASCII.GetBytes(msg);
string IP = "127.0.0.1";
int port = 904;
IPEndPoint ep = new IPEndPoint(IPAddress.Parse(IP), port);
Socket client = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
client.SendTo(packetData, ep);
Console.WriteLine("Data sent!");
int recv;
byte[] data = new byte[1024];
EndPoint tmpRemote = (EndPoint)ep;
while(true)
{
//READ MESSAGE FROM SERVER
recv = client.ReceiveFrom(data, ref tmpRemote);
Console.WriteLine("Messaged received from: " + tmpRemote.ToString());
Console.WriteLine(Encoding.ASCII.GetString(data, 0, recv));
}
client.Close();
Console.WriteLine("Client disconnected.");
Console.ReadLine();
}
I can't get the server to talk back to the client and have the client read/display the server's reply.
change this sentence
sock.SendTo(data, tmpRemote);
to
newSocket.SendTo(data, tmpRemote);
and remove these sentences, you have bind local EndPoint twice.
Socket sock = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
sock.Bind(tmpRemote);
In Net, you can use UdpClient instead of Socket.
If you want a demo, look at this demo.
I have a program that multiple clients would be able to connect to a server using a socket:
private void performConnect()
{
while (true)
{
if (myList.Pending())
{
thrd = thrd + 1;
tcpClient = myList.AcceptTcpClient();
IPEndPoint ipEndPoint = (IPEndPoint)tcpClient.Client.RemoteEndPoint;
string clientIP = ipEndPoint.Address.ToString();
nStream[thrd] = tcpClient.GetStream();
currentMsg = "\n New IP client found :" + clientIP;
recieve[thrd].Start();
this.Invoke(new rcvData(addNotification));
try
{
addToIPList(clientIP);
}
catch (InvalidOperationException exp)
{
Console.Error.WriteLine(exp.Message);
}
Thread.Sleep(1000);
}
}
}
then the server could send data (chat messages) to a chosen client, using this code.
private void sendData(String data)
{
IPAddress ipep =IPAddress.Parse(comboBox1.SelectedItem.ToString());
Socket server = new Socket(AddressFamily.InterNetwork , SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipept = new IPEndPoint( ipep, hostPort);
NetworkStream nStream = tcpClient.GetStream();
ASCIIEncoding asciidata = new ASCIIEncoding();
byte[] buffer = asciidata.GetBytes(data);
if (nStream.CanWrite)
{
nStream.Write(buffer, 0, buffer.Length);
nStream.Flush();
}
}
the problem is that whatever IP i choose from the combo box, the message i send would always be directed/sent to the last IP that connected to the server.. Please somebody pinpoint my error! all help would be appreciated.
Look at those lines:
IPAddress ipep =IPAddress.Parse(comboBox1.SelectedItem.ToString());
Socket server = new Socket(AddressFamily.InterNetwork , SocketType.Stream, ProtocolType.Tcp);
IPEndPoint ipept = new IPEndPoint( ipep, hostPort);
NetworkStream nStream = tcpClient.GetStream();
You are creating a new socket but you are sending the data to the socket stored in the variable tcpClient that is global (since it was not defined in the method), thus totally ignoring the IPEndPoint parsed from the combobox.
You should not create a new socket in order to send data to the clients. Instead, store all clients in a collection and retrieve the appropriate one based on the input of the combobox.
I'm working with sockets in C# and I'm getting the following error:
A request to send or receive data was
disallowed because the socket is not
connected and (when sending on a
datagram socket using a sendto call)
no address was supplied
Here is the code that I'm executing:
private void HostSubscriberService()
{
IPAddress ipV4 = PublisherService.ReturnMachineIP();
var localEP = new IPEndPoint(ipV4, _port);
var server = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
server.Bind(localEP);
StartListening(server);
}
private void StartListening(Socket server)
{
EndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);
while (true)
{
var data = new byte[1024];
int recv = server.ReceiveFrom(data, ref remoteEP);
string messageSendFromClient = Encoding.ASCII.GetString(data, 0, recv);
MessageBox.Show(messageSendFromClient);
}
}
The error happens # int recv = server.ReceiveFrom(data, ref remoteEP);
I just need to listen for new incoming connections and then print the message that was sent from the new client.
I need it to work on the TCP protocol, because some of the messages will be > 1500 bytes
Thanks!
You need to .BeginAccept() before you can receive.
Here's a link with a sinple Asynchronous Socket Server example
ReceiveFrom() is for UDP, use Accept() and Receive() for TCP