// author:			frenchwhale (http://frenchwhales_site.tripod.com)
//					for the WinSock tutorial
//
// file name:       wsserver.c
//
// description:     A TCP server that uses Winsock to
//                  listen for connections, receives data,
//                  and answers with a pre-specified message
// Copyright 2002 frenchwhale

#define MESSAGE         "Hello, Client!\n"

#include <winsock.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, int **argv)
{
   WSADATA wsda;			// Structure to store information returned from
					// WSAStartup

   char szRepMessage[80];               // Store the reply message
   int iMessageLen;

   int ret;                             // Return values

   char szInBuffer[128];
   int iBufferLen;

   int iPort, iAddrLen;

   SOCKET sListen, sClient;                    // Our TCP socket handle
   SOCKADDR_IN addr,            // The local interface
               remote_addr;     // The address of the connecting host

   // Check arguments
   if(argc != 2 || (argc==2 && strcmp((char *) &argv[1][0], "/?")==0))
   {
      printf("wsserver port\n");
      printf("   port:   the listening port\n");
      exit(1);
   }

   // Get the remote port
   iPort = atoi((char *) &argv[1][0]);

   if(iPort<0 || iPort>65563)   // 0 < iPort < 65563
   {
      printf("Invalid port number! (%s)\n", argv[2]);
      exit(1);
   }

   strcpy(szRepMessage, MESSAGE);
   iMessageLen = strlen(szRepMessage);


   // Load version 1.1 of Winsock

   WSAStartup(MAKEWORD(1,1), &wsda);

   // Create a TCP socket
   printf("Creating socket...");
   sListen = socket(AF_INET, SOCK_STREAM, IPPROTO_IP);

   // Error?
   if(sListen == SOCKET_ERROR)
   {
      printf("Error\nCall to socket(AF_INET, SOCK_STREAM, IPPROTO_IP); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   printf("OK\n");

   printf("Binding socket to port %d...", iPort);

   addr.sin_family = AF_INET;
   addr.sin_port = htons(iPort);
   addr.sin_addr.s_addr = htonl(INADDR_ANY);          // Listen on any interface

   ret = bind(sListen, (struct sockaddr *) &addr, sizeof(addr));

   // Error?
   if(ret == SOCKET_ERROR)
   {
      printf("Error\nCall to bind(sListen, (struct sockaddr *) &addr, sizeof(addr)); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   printf("OK\n");

   printf("Putting socket into listening mode...");

   ret = listen(sListen, 10);        // Backlog 10

   // Error?
   if(ret == SOCKET_ERROR)
   {
      printf("Error\nCall to listen(sListen, 10); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   printf("OK\n");

   printf("Waiting for connections (Press Ctrl-C to exit)...");

   iAddrLen = sizeof(remote_addr);

   sClient = accept(sListen, (struct sockaddr *) &remote_addr, &iAddrLen);

   // Error?
   if(sClient == SOCKET_ERROR)
   {
      printf("Error\nCall to accept(sListen, (struct sockaddr *) remote_addr, sizeof(remote_addr)); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }

   printf("%s connected\n",
          inet_ntoa(remote_addr.sin_addr));

   // Receive data

   printf("Waiting for a response...");
   ret = recv(sClient, szInBuffer, sizeof(szInBuffer), 0);

   if(ret == SOCKET_ERROR)
   {
      printf("Error\nCall to recv(sClient, szInBuffer, sizeof(szInBuffer), 0); failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }
   printf("Response recieved\n");

   iBufferLen = ret;		// recv() returns the number of bytes read

   szInBuffer[iBufferLen] = '\0';	// convert to cstring

   printf("Data recieved:\n%s\n", szInBuffer);

   // Ready to send data

   printf("Sending reply...");
   ret = send(sClient, szRepMessage, iMessageLen, 0);

   if(ret == SOCKET_ERROR)
   {
      printf("Error\nCall to send(sClient, szRepMessage, iMessageLen, 0) failed with:\n%d\n", WSAGetLastError());
      exit(1);
   }
   printf("OK\n");

   printf("Closing client socket...");
   closesocket(sClient);
   printf("OK\n");

   return 0;
}