tcp.c

/*
** tcp.c                         A small ISC TCP/IP subsystem demo program
**
** Copyright (c) 1992 Peter Eriksson and Per Cederqvist of the
**                    Lysator Academic Computer Association.
**
** history:
** 910306 pen      initial coding
** 920211 pen      cleaned up
*/

#include <stdio.h>
#include <errno.h>

/*
** Could do a "#define ISC_UDGTYPE foobar" to change the type of
** the (IscSession) 'udg' member pointer type from "void *" to "foobar *".
*/
#include <isc.h>


extern void abort(void);

static IscConfig cfg =
{
  1005,
  {
    1001,
    { -1, -1, -1, -1, -1 }
  },
  {
    1001,
    { NULL, NULL, NULL },
    NULL
  }
};

#define TIMEOUT    30000    /* 30 seconds */

Perror(char *msg)
{
  perror(msg);
  exit(1);
}

void
main(void)
{
  IscMaster   * mcb;   /* ISC master control block */
  IscSession  * scb;   /* ISC session control block */
  IscEvent    * ecb;   /* ISC event control block */



  puts("Beginning operation...");
  
  /*
  ** Initialize the ISC subsystem, create a Master Control Block
  */
  if ((mcb = isc_initialize(&cfg)) == NULL)
    Perror("isc_initialize");

  puts("ISC initialized, connecting to remote service...");
  
  /*
  ** Establish a TCP session to a remote service (IRC)
  */
  if ((scb = isc_opentcp(mcb, "obel5.ida.liu.se", "2000")) == NULL)
    Perror("isc_opentcp");

  puts("Connection initiated, enabling listening ports...");
  
  /*
  ** Enable remote connection attempts at port #20000 and #20001
  */
  if (isc_listentcp(mcb, "localhost", "20000") == NULL)
    Perror("isc_listentcp-20000");

  if (isc_listentcp(mcb, NULL, "20001") == NULL)
    Perror("isc_listentcp-20001");

  puts("Listening ports installed, entering main event loop...");
  
  /*
  ** Handle all events
  */
  while (ecb = isc_getnextevent(mcb, TIMEOUT))
  {
    switch (ecb->event)
    {
      case ISC_EVENT_CONNECTED:
        puts("Server connection established.");
	break;
	
      case ISC_EVENT_REJECTED:
        puts("Server connection rejected.");
	isc_destroy(mcb, scb);
	scb = NULL;
	break;
	
      case ISC_EVENT_ERROR: /* ISC subsystem error */
	fprintf(stderr, "ISC-ERROR: errno = %d", errno);
	if (ecb->msg)
	  fprintf(stderr, " (%s)", ecb->msg->buffer);
	putc('\n', stderr);

	/*
	** Should probably do something more sensible than
	** just finishing off the session
	*/
	if (ecb->session)
	  isc_destroy(mcb, ecb->session);
	break;

      case ISC_EVENT_TIMEOUT: /* Timeout limit reached */
	puts("*** Timeout ***");
	break;

      case ISC_EVENT_LOGIN: /* New client requesting connection */
	{
	  char laddr[256];
	  char lserv[256];
	  char raddr[256];
	  char rserv[256];
	  
	  strcpy(raddr, "<unknown>");
	  strcpy(rserv, "<unknown>");
	  strcpy(laddr, "<unknown>");
	  strcpy(lserv, "<unknown>");

	  fetch_address(ecb->session->info.tcp.raddr,
			raddr,
			sizeof(raddr)-1,
			rserv,
			sizeof(rserv)-1);

	  fetch_address(ecb->session->info.tcp.laddr,
			laddr,
			sizeof(laddr)-1,
			lserv,
			sizeof(lserv)-1);
			   
	  
	  printf("New session #%d on %s/%s connecting from: %s/%s\n",
		 ecb->session,
		 laddr, lserv,
		 raddr, rserv);
	
	  /*
	  ** Here we could assign the 'ecb->session->udg' member some
	  ** arbitrary value to be used later by our own routines
	  */
	}
	break;

      case ISC_EVENT_LOGOUT: /* Client closed connection */
	if (ecb->session == scb)
	  printf("Server disconnecting\n");
	else
	  printf("Client #%d disconnecting\n", ecb->session);

	/*
	** Deallocate the storage reserved for the session
	*/
	isc_destroy(mcb, ecb->session);
	break;

      case ISC_EVENT_MESSAGE: /* Message from client or server */
	if (ecb->session == scb)
	  printf("Message from server: '%s'\n", ecb->msg->buffer);
	else
	{
	  printf("Message from client #%d: '%s'\n",
		 ecb->session,
		 ecb->msg->buffer);

	  /*
	  ** Reply with some text to the client
	  */
	  isc_write(ecb->session, "OK, got it\n\r", 12);
	  isc_flush(ecb->session);
	}
	break;

      default: /* NOTREACHED - OR SHOULDN'T BE ATLEAST :-) */
	Perror("NOTREACHED");
    }

    /*
    ** Finished with the event, lets get rid of it
    */
    isc_dispose(ecb);
  }

  /* NOTREACHED - I THINK ... */
  Perror("SHUTDOWN");
}


const char *strerror(int num)
{
  static char foo[256];

  sprintf(foo, "Error #%d", num);
  return foo;
}


fetch_address(IscAddress *ia,
	      char *host,
	      int hlen,
	      char *port,
	      int plen)
{
  char *cp;


  cp = isc_gethostname(ia, host, hlen);
  if (!cp)
    isc_getipnum(ia, host, hlen);

  cp = isc_getservice(ia, port, plen, ISC_TYPE_TCP);
  if (!cp)
    sprintf(port, "%d", isc_getportnum(ia));
}