/*
  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 <stdlib.h>
#include <string.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <protocols/talkd.h>
#include <netdb.h>
#include <stdio.h>
#include <unistd.h>
#if defined HAVE_IDN2_H && defined HAVE_IDN2
# include <idn2.h>
#elif defined HAVE_IDNA_H
# include <idna.h>
#endif

#include "talk_ctl.h"

int
get_addrs (char *my_machine_name, char *his_machine_name)
{
#if HAVE_DECL_GETADDRINFO || defined HAVE_IDN || defined HAVE_IDN2
  int err;
#endif
  char *lhost, *rhost;
#if HAVE_DECL_GETADDRINFO
  struct addrinfo hints, *res, *ai;
#else /* !HAVE_DECL_GETADDRINFO */
  struct hostent *hp;
#endif
  struct servent *sp;

#if defined HAVE_IDN || defined HAVE_IDN2
  err = idna_to_ascii_lz (my_machine_name, &lhost, 0);
  if (err)
    {
      fprintf (stderr, "talk: %s: %s\n",
	       my_machine_name, idna_strerror (err));
      exit (-1);
    }

  err = idna_to_ascii_lz (his_machine_name, &rhost, 0);
  if (err)
    {
      fprintf (stderr, "talk: %s: %s\n",
	       his_machine_name, idna_strerror (err));
      exit (-1);
    }
#else /* !HAVE_IDN && !HAVE_IDN2 */
  lhost = my_machine_name;
  rhost = his_machine_name;
#endif

  msg.pid = htonl (getpid ());

  /* Look up the address of the local host.  */

#if HAVE_DECL_GETADDRINFO
  memset (&hints, 0, sizeof (hints));

  /* The talk-protocol is IPv4 only!  */
  hints.ai_family = AF_INET;
  hints.ai_socktype = SOCK_DGRAM;
# ifdef AI_IDN
  hints.ai_flags |= AI_IDN;
# endif

  err = getaddrinfo (lhost, NULL, &hints, &res);
  if (err)
    {
      fprintf (stderr, "talk: %s: %s\n", lhost, gai_strerror (err));
      exit (-1);
    }

  /* Perform all sanity checks available.
   * Reduction of tests?
   */
  for (ai = res; ai; ai = ai->ai_next)
    {
      int f;

      if (ai->ai_family != AF_INET)
	continue;

      f = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol);
      if (f < 0)
	continue;

      /* Attempt binding to this local address.  */
      if (bind (f, ai->ai_addr, ai->ai_addrlen))
	{
	  close (f);
	  f = -1;
	  continue;
	}

      /* We have a usable address.  */
      close (f);
      break;
    }

  if (ai)
    memcpy (&my_machine_addr,
	    &((struct sockaddr_in *) ai->ai_addr)->sin_addr,
	    sizeof (my_machine_addr));

  freeaddrinfo (res);
  if (!ai)
    {
      fprintf (stderr, "talk: %s: %s\n", lhost, "address not found");
      exit (-1);
    }

#else /* !HAVE_DECL_GETADDRINFO */
  hp = gethostbyname (lhost);
  if (hp == NULL)
    {
      fprintf (stderr, "talk: %s(%s): ", lhost, my_machine_name);
      herror ((char *) NULL);
      exit (-1);
    }
  memmove (&my_machine_addr, hp->h_addr, hp->h_length);
#endif /* !HAVE_DECL_GETADDRINFO */

  /*
   * If the callee is on-machine, just copy the
   * network address, otherwise do a lookup...
   */
  if (strcmp (rhost, lhost))
    {
#if HAVE_DECL_GETADDRINFO
      err = getaddrinfo (rhost, NULL, &hints, &res);
      if (err)
	{
	  fprintf (stderr, "talk: %s: %s\n", rhost, gai_strerror (err));
	  exit (-1);
	}

      /* Perform all sanity checks available.  */
      for (ai = res; ai; ai = ai->ai_next)
	{
	  int f;

	  if (ai->ai_family != AF_INET)
	    continue;

	  f = socket (ai->ai_family, ai->ai_socktype, ai->ai_protocol);
	  if (f < 0)
	    continue;

	  /* We have a usable address family!  */
	  close (f);
	  break;
	}

      if (ai)
	memcpy (&his_machine_addr,
		&((struct sockaddr_in *) ai->ai_addr)->sin_addr,
		sizeof (his_machine_addr));

      freeaddrinfo (res);
      if (!ai)
	{
	  fprintf (stderr, "talk: %s: %s\n", rhost, "address not found");
	  exit (-1);
	}

#else /* !HAVE_DECL_GETADDRINFO */
      hp = gethostbyname (rhost);
      if (hp == NULL)
	{
	  fprintf (stderr, "talk: %s(%s): ", rhost, his_machine_name);
	  herror ((char *) NULL);
	  exit (-1);
	}
      memmove (&his_machine_addr, hp->h_addr, hp->h_length);
#endif /* !HAVE_DECL_GETADDRINFO */
    }
  else
    his_machine_addr = my_machine_addr;

  /* Find the server's port.  */
  sp = getservbyname ("ntalk", "udp");
  if (sp == 0)
    {
      fprintf (stderr, "talk: %s/%s: service is not registered.\n",
	       "ntalk", "udp");
      exit (-1);
    }
  daemon_port = ntohs (sp->s_port);

#if defined HAVE_IDN || defined HAVE_IDN2
  free (lhost);
  free (rhost);
#endif

  return 0;
}