inetutils/talk/invite.c

/*
  Copyright (C) 1995-2025 Free Software Foundation, Inc.

  This file is part of GNU Inetutils.

  GNU Inetutils is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 3 of the License, or (at
  your option) any later version.

  GNU Inetutils is distributed in the hope that it will be useful, but
  WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with this program.  If not, see `http://www.gnu.org/licenses/'. */

/*
 * Copyright (c) 1983, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

#include <config.h>

#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <sys/time.h>
#include <time.h>
#include <signal.h>
#include <netinet/in.h>
#include <protocols/talkd.h>
#include <errno.h>
#include <unistd.h>
#include <setjmp.h>
#include <attribute.h>
#include "talk_ctl.h"
#include "talk.h"

static char *answers[] = {
  "answer #0",			/* SUCCESS */
  "Your party is not logged on",	/* NOT_HERE */
  "Target machine is too confused to talk to us",	/* FAILED */
  "Target machine does not recognize us",	/* MACHINE_UNKNOWN */
  "Your party is refusing messages",	/* PERMISSION_REFUSED */
  "Target machine cannot handle remote talk",	/* UNKNOWN_REQUEST */
  "Target machine indicates protocol mismatch",	/* BADVERSION */
  "Target machine indicates protocol botch (addr)",	/* BADADDR */
  "Target machine indicates protocol botch (ctl_addr)",	/* BADCTLADDR */
};

#define NANSWERS	(sizeof (answers) / sizeof (answers[0]))

/*
 * The msg.id's for the invitations
 * on the local and remote machines.
 * These are used to delete the
 * invitations.
 */
int local_id, remote_id;
jmp_buf invitebuf;

/*
 * Transmit the invitation and process the response
 */
int
announce_invite (void)
{
  CTL_RESPONSE response;

  current_state = "Trying to connect to your party's talk daemon";
  ctl_transact (his_machine_addr, msg, ANNOUNCE, &response);
  remote_id = response.id_num;
  if (response.answer != SUCCESS)
    {
      if (response.answer < NANSWERS)
	message (answers[response.answer]);
      quit ();
    }
  /* leave the actual invitation on my talk daemon */
  ctl_transact (my_machine_addr, msg, LEAVE_INVITE, &response);
  local_id = response.id_num;

  return 0;
}

/*
 * Routine called on interrupt to re-invite the callee
 */
void
re_invite (int sig MAYBE_UNUSED)
{

  message ("Ringing your party again");
  current_line++;
  /* force a re-announce */
  msg.id_num = htonl (remote_id + 1);
  announce_invite ();
  longjmp (invitebuf, 1);
}

int
invite_remote (void)
{
  int new_sockt;
  struct itimerval itimer;
  CTL_RESPONSE response;

  itimer.it_value.tv_sec = RING_WAIT;
  itimer.it_value.tv_usec = 0;
  itimer.it_interval = itimer.it_value;
  if (listen (sockt, 5) != 0)
    p_error ("Error on attempt to listen for caller");

  msg.addr.sa_family = htons (my_addr.sin_family);
  memcpy (msg.addr.sa_data,
	  ((struct sockaddr *) &my_addr)->sa_data,
	  sizeof ((struct sockaddr *) & my_addr)->sa_data);

  msg.id_num = htonl (-1);	/* an impossible id_num */
  invitation_waiting = 1;
  announce_invite ();
  /*
   * Shut off the automatic messages for a while,
   * so we can use the interrupt timer to resend the invitation
   */
  end_msgs ();
  setitimer (ITIMER_REAL, &itimer, (struct itimerval *) 0);
  message ("Waiting for your party to respond");
  signal (SIGALRM, re_invite);
  setjmp (invitebuf);
  while ((new_sockt = accept (sockt, 0, 0)) < 0)
    {
      if (errno == EINTR)
	continue;
      p_error ("Unable to connect with your party");
    }
  close (sockt);
  sockt = new_sockt;

  /*
   * Have the daemons delete the invitations now that we
   * have connected.
   */
  current_state = "Waiting for your party to respond";
  start_msgs ();

  msg.id_num = htonl (local_id);
  ctl_transact (my_machine_addr, msg, DELETE, &response);
  msg.id_num = htonl (remote_id);
  ctl_transact (his_machine_addr, msg, DELETE, &response);
  invitation_waiting = 0;

  return 0;
}

/*
 * Tell the daemon to remove your invitation
 */
int
send_delete (void)
{

  msg.type = DELETE;
  /*
   * This is just a extra clean up, so just send it
   * and don't wait for an answer
   */
  msg.id_num = htonl (remote_id);
  daemon_addr.sin_family = AF_INET;
#ifdef HAVE_STRUCT_SOCKADDR_IN_SIN_LEN
  daemon_addr.sin_len = sizeof (daemon_addr);
#endif
  daemon_addr.sin_addr = his_machine_addr;
  if (sendto (ctl_sockt, (const char *) &msg, sizeof (msg), 0,
	      (struct sockaddr *) &daemon_addr,
	      sizeof (daemon_addr)) != sizeof (msg))
    perror ("send_delete (remote)");
  msg.id_num = htonl (local_id);
  daemon_addr.sin_addr = my_machine_addr;
  if (sendto (ctl_sockt, (const char *) &msg, sizeof (msg), 0,
	      (struct sockaddr *) &daemon_addr,
	      sizeof (daemon_addr)) != sizeof (msg))
    perror ("send_delete (local)");

  return 0;
}