After the receive problem was resolved, I tried to get four sockets working. I was only able to get three. Not the four expected.
Following is the code for an echo server which can handle multiple sessions:
using System;
using System.Threading;
using Microsoft.SPOT;
using Microsoft.SPOT.Hardware;
using GHIElectronics.NETMF.FEZ;
using GHIElectronics.NETMF.Net;
using GHIElectronics.NETMF.Net.Sockets;
using GHIElectronics.NETMF.Net.NetworkInformation;
using System.Text;
//using Socket = GHIElectronics.NETMF.Net.Sockets.Socket;
namespace EchoServer
{
public class EchoServer
{
private static int sessionCount = 0;
private const int MAX_SESSIONS = 4;
// putting the new session into a static variable
// to be picked up by the new session thread is
// NOT a good idea. It will create a race condition
// should two sessions start at the same time
// This was only done for testing...
private static Socket newSessionSocket = null;
public static void Main()
{
const Int32 c_port = 80;
byte[] ip = { 192, 168, 1, 201 };
byte[] subnet = { 255, 255, 255, 0 };
byte[] gateway = { 192, 168, 1, 1 };
byte[] mac = { 43, 185, 44, 2, 206, 127 };
WIZnet_W5100.Enable(SPI.SPI_module.SPI1, (Cpu.Pin)FEZ_Pin.Digital.Di10, (Cpu.Pin)FEZ_Pin.Digital.Di9);
NetworkInterface.EnableStaticIP(ip, subnet, gateway, mac);
NetworkInterface.EnableStaticDns(new byte[] { 192, 168, 1, 1 });
Socket server = new Socket(AddressFamily.InterNetwork,
SocketType.Stream, ProtocolType.Tcp);
IPEndPoint localEndPoint = new IPEndPoint(IPAddress.Any, c_port);
server.Bind(localEndPoint);
server.Listen(1);
Debug.Print("*** Echo Server Listening");
while (true)
{
// check for four running sessions
if (sessionCount < MAX_SESSIONS)
{
// Wait for a client to connect.
newSessionSocket = server.Accept();
Debug.Print("New Sesion");
Thread newSession = new Thread(new ThreadStart(SessionThread));
newSession.Start();
Thread.Sleep(0);
Interlocked.Increment(ref sessionCount);
}
else
{
Thread.Sleep(250);
}
}
}
static private void SessionThread()
{
byte[] buffer = new byte[1024];
Socket socket = newSessionSocket;
socket.ReceiveTimeout = -1;
while (true)
{
try
{
if (socket.Poll(-1, SelectMode.SelectRead))
{
int bytesToRead = socket.Available;
//Debug.Print("bytesToRead: " + bytesToRead.ToString());
if (bytesToRead == 0)
{
throw new Exception("Remote Disconnect");
}
else
{
int bytesRead = socket.Receive(buffer, bytesToRead, SocketFlags.None);
socket.Send(buffer, bytesRead, SocketFlags.None);
socket.Poll(-1, SelectMode.SelectWrite);
}
}
else
{
Debug.Print("Poll False");
}
}
catch (Exception ex)
{
socket.Close();
Interlocked.Decrement(ref sessionCount);
break;
}
}
}
}
}
Upon startup, one socket is consumed with the listening socket. I was then able to get two sessions working. When I started the third session, which would have been the fourth socket, I got the following output:
*** Echo Server Listening
New Sesion
New Sesion
#### Exception System.Exception - 0x00000000 (1) ####
#### Message: No free sockets
#### GHIElectronics.NETMF.Net.SocketNative::socket [IP: 0024] ####
#### GHIElectronics.NETMF.Net.SocketNative::accept [IP: 0007] ####
#### GHIElectronics.NETMF.Net.Sockets.Socket::Accept [IP: 0023] ####
#### EchoServer.EchoServer::Main [IP: 009b] ####
A first chance exception of type ‘System.Exception’ occurred in GHIElectronics.NETMF.W5100.dll
An unhandled exception of type ‘System.Exception’ occurred in GHIElectronics.NETMF.W5100.dll
Additional information: No free sockets
