/***************************************************************************

   tcp_server.c    Designed as a simple class example.  The program waits for
                   a request.  It assumes that request is numerical.  It adds
                   +1 to the input and sends it back.

   This program expects no arguments:
   tcp_server
   

   Version 1.0   Ocotber, 2002 Yvan Petillot.
****************************************************************************/

#include       <stdlib.h>
#include       <sys/socket.h>
#include       <netinet/in.h>

#define         TRUE            1
#define         FALSE           0
#define         BUFFER_SIZE     100
#define         PORT            10000

void    SysError( char * );

/* Main Program */
main ( int argc, char *argv[] )
{
  long               input_value;
  int                family = AF_INET;       /* The default for most cases */
  int                type   = SOCK_STREAM;   /* Says it's a TCP connection */
  in_port_t          port   = PORT;          /* Use a free port to establish connection */
  int                result;
  struct sockaddr_in server;                 /* Structure storing socket info */
  struct sockaddr_in client;                 /* Structure storing socket info */
  int                lsa = sizeof(server);
  int                fdListen, fdConn, fd;   /* Socket id. On Unix a socket is a file descriptor */
  char               console_buffer[BUFFER_SIZE];
  char               ip_input_buffer[BUFFER_SIZE];
  char               ip_output_buffer[BUFFER_SIZE];

  /* Create socket*/
  if ((fd = socket (family, type, 0)) < 0)
    {
      SysError ("Error on socket");
    }
  /* Fills sa socket structure with correct fields */
  server.sin_family       = family;
  server.sin_port         = port;              /* port*/
  server.sin_addr.s_addr  = htonl(INADDR_ANY); /* the kernel assigns the IP addr*/
 
  /* Server code */
  /* First bind fd and sa structure*/ 
  if (bind (fd, (struct sockaddr *)&server, lsa ) == -1)
    SysError ("Error on bind");
  /* Now listen for a client to connect */
  if (listen (fd, SOMAXCONN) == -1)   /* set up for listening */
    SysError ("Error on listen");
  
  fdListen = fd;
  /* Infinite loop until fault */
  while( TRUE )
    {
      /* Wait for a client and do accept */
      if ((fdConn = accept (fdListen, (struct sockaddr *)&client, &lsa )) <0)
	SysError ("Error on accept");
      printf("Got Connection from %s\n",inet_ntoa(client.sin_addr));
      /* After Accept Create Son and handle connection */
      if (!fork())
      {
	/* Fd not needed in child */
	close(fd);
	/*Make sure inout buffer is void */
	bzero( ip_input_buffer, sizeof( ip_input_buffer ));
	/* While client is sending info  This is blocking*/ 
	while ( recv( fdConn, ip_input_buffer, BUFFER_SIZE - 2, 0 ) > 0 )
	  {
	    /* Old version */
	    /* Get Value
	       input_value = atoi( ip_input_buffer );
	       /* Increment value by one
		  input_value = input_value + 1;*/
	    /* Make sure output buffer is empty */
	    bzero( ip_output_buffer, sizeof( ip_output_buffer ));
	    /* Put output value in output buffer */
	    strcpy(ip_output_buffer,ip_input_buffer);
	    //sprintf( ip_output_buffer, "%d", input_value );
	    /* Send value back to client */
	    if ( send( fdConn, ip_output_buffer, 
		       strlen(ip_output_buffer) +1, 0) <= 0 )
	      SysError( "Error on send" );
	    
	  }          
	}/* End of while recv is successful */
	close (fdConn);
	}                           /* End of while TRUE    */
}                                   /* End of server case   */


void    SysError( char *string )
{
  printf( "Error found:  String given is --> %s\n", string );
  exit(0);
}