/*
 *  iptools.c -- Some useful TCP/IP utils
 *
 *  iptools.c is a part of binkd project
 *
 *  Copyright (C) 1997-1998  Dima Maloff, 5047/13
 *
 *  This program 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 2 of the License, or
 *  (at your option) any later version. See COPYING.
 */

/*
 * $Id: iptools.c,v 2.10 2003/05/26 20:37:59 gul Exp $
 *
 * $Log: iptools.c,v $
 * Revision 2.10  2003/05/26 20:37:59  gul
 * typo in previous patch
 *
 * Revision 2.9  2003/05/26 20:34:38  gul
 * Bugfix on resolving raw IP when HAVE_FORK
 *
 * Revision 2.8  2003/05/04 08:45:30  gul
 * Lock semaphores more safely for resolve and IP-addr print
 *
 * Revision 2.7  2003/03/26 12:59:16  gul
 * Fix previous patch
 *
 * Revision 2.6  2003/03/26 10:44:40  gul
 * Code cleanup
 *
 * Revision 2.5  2003/03/25 20:37:46  gul
 * free_hostent() function
 *
 * Revision 2.4  2003/03/01 18:46:05  gul
 * Use HAVE_SYS_IOCTL_H macro
 *
 * Revision 2.3  2003/02/28 08:53:38  gul
 * Fixed proxy usage
 *
 * Revision 2.2  2003/02/22 12:12:33  gul
 * Cleanup sources
 *
 * Revision 2.1  2003/02/22 11:45:41  gul
 * Do not resolve hosts if proxy or socks5 using
 *
 * Revision 2.0  2001/01/10 12:12:38  gul
 * Binkd is under CVS again
 *
 * Revision 1.3  1998/06/19  05:19:33  mff
 * changes in get_hostname()
 *
 * Revision 1.2  1997/10/23  04:01:29  mff
 * +find_port(), minor changes for Amiga port
 *
 * Revision 1.1  1997/03/28  06:52:14  mff
 * Initial revision
 */

#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <ctype.h>

#if defined(HAVE_SYS_IOCTL_H)
#include <sys/ioctl.h>
#endif

#include "iphdr.h"
#include "iptools.h"
#include "tools.h"
#include "readcfg.h"
#include "sem.h"

/*
 * Finds ASCIIZ address
 */
const char *get_hostname (struct sockaddr_in *addr, char *host, int len)
{
  struct hostent *hp;
  struct sockaddr_in s;

  memcpy(&s, addr, sizeof(s));
  if (backresolv)
  {
    lockresolvsem();
    hp = gethostbyaddr ((char *) &s.sin_addr, sizeof s.sin_addr, AF_INET);
    if (hp)
    {
      strnzcpy (host, hp->h_name, len);
      releaseresolvsem();
      return host;
    }
    releaseresolvsem();
  }
  lockhostsem();
  strncpy (host, inet_ntoa (s.sin_addr), len);
  releasehostsem();
  return host;
}

#ifdef HAVE_THREADS
struct hostent *copy_hostent(struct hostent *dest, struct hostent *src)
{
  int naddr;
  char **cp;

  memcpy(dest, src, sizeof(struct hostent));
  for (cp = src->h_addr_list, naddr = 0; cp && *cp; naddr++, cp++);
  dest->h_addr_list = malloc((naddr+1)*sizeof(dest->h_addr_list[0]));
  if (dest->h_addr_list)
  {
    dest->h_addr_list[0] = malloc(naddr*src->h_length);
    if (dest->h_addr_list[0])
    {
      for (cp = src->h_addr_list, naddr=0; cp && *cp; cp++, naddr++)
      {
        dest->h_addr_list[naddr] = dest->h_addr_list[0]+naddr*src->h_length;
        memcpy(dest->h_addr_list[naddr], *cp, src->h_length);
      }
      dest->h_addr_list[naddr] = NULL;
    }
  }
  return dest;
}

void free_hostent(struct hostent *hp)
{
  if (hp)
  {
    if (hp->h_addr_list && hp->h_addr_list[0])
      free(hp->h_addr_list[0]);
    if (hp->h_addr_list)
      free(hp->h_addr_list);
    hp->h_addr_list = NULL;
  }
}
#endif

/*
 * Sets non-blocking mode for a given socket
 */
void setsockopts (SOCKET s)
{

#if defined(FIONBIO)
#if defined(UNIX) || defined(IBMTCPIP) || defined(AMIGA)
  int arg;

  arg = 1;
  if (ioctl (s, FIONBIO, (char *) &arg, sizeof arg) < 0)
    Log (1, "ioctl (FIONBIO): %s", TCPERR ());

#elif defined(WIN32)
  u_long arg;

  arg = 1;
  if (ioctlsocket (s, FIONBIO, &arg) < 0)
    Log (1, "ioctlsocket (FIONBIO): %s", TCPERR ());
#endif
#endif

#if defined(UNIX) || defined(EMX) || defined(AMIGA)
  if (fcntl (s, F_SETFL, O_NONBLOCK) == -1)
    Log (1, "fcntl: %s", strerror (errno));
#endif
}

/*
 * Find the port number (in the host byte order) by a port number string or
 * a service name. Find_port ("") will return binkp's port from
 * /etc/services or even (if there is no binkp entry) 24554.
 * Returns 0 on error.
 */
int find_port (char *s)
{
  struct servent *entry = getservbyname (*s ? s : PRTCLNAME, "tcp");

  if (entry)
    return ntohs (entry->s_port);
  if (*s == 0)
    return DEF_PORT;
  if (isdigit (*s))
    return atoi (s);

  Log (1, "%s: incorrect port", s);
  return 0;
}

/*
 * Find the host IP address list by a domain name or IP address string.
 * Returns NULL on error.
 */
struct hostent *find_host(char *host, struct hostent *he, struct in_addr *defaddr)
{
  struct hostent *hp;
#ifdef HAVE_THREADS
  struct hostent ht;
  char *alist[2];
#else
  static struct hostent ht;
  static char *alist[2];
#endif

  if (!isdigit(host[0]) ||
      (defaddr->s_addr = inet_addr (host)) == INADDR_NONE)
  {
    /* If not a raw ip address, try nameserver */
    Log (5, "resolving `%s'...", host);
    lockresolvsem();
    if ((hp = gethostbyname(host)) == NULL)
    {
      Log(1, "%s: unknown host", host);
      releaseresolvsem();
      return NULL;
    }
    hp = copy_hostent(he, hp);
    releaseresolvsem();
    return hp;
  }
  /* Raw ip address, fake */
  hp = &ht;
  hp->h_name = host;
  hp->h_aliases = 0;
  hp->h_addrtype = AF_INET;
  hp->h_length = sizeof (struct in_addr);
  hp->h_addr_list = alist;
  hp->h_addr_list[0] = (char *) defaddr;
  hp->h_addr_list[1] = (char *) 0;
  hp = copy_hostent(he, hp);
  return hp;
}