/* Copyright (C) 1997, 1998, 1999, 2000, 2001 Free Software Foundation, Inc.   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.   This program 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, write to the Free Software   Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,   MA 02110-1301 USA. */#ifdef HAVE_CONFIG_H#include <config.h>#endif#include <errno.h>#include <string.h>#include <stdio.h>#include <stdlib.h>#include <unistd.h>#include <sys/types.h>#include <sys/socket.h>/* Solaris at least earlier 2.6 and before does not include   the ioctl definitions if BSD_COMP is not set.  */#if defined(__svr4__)# define BSD_COMP 1#endif#include <sys/ioctl.h>#include <net/if.h>#include <ifconfig.h>unsigned intif_nametoindex (const char *ifname){  int result = 0;#ifdef SIOCGIFINDEX  {    int fd = socket (AF_INET, SOCK_DGRAM, 0);    if (fd >= 0)      {	struct ifreq ifr;	strncpy (ifr.ifr_name, ifname, sizeof (ifr.ifr_name));	ifr.ifr_name[IFNAMSIZ - 1] = '\0';	result = ioctl (fd, SIOCGIFINDEX, &ifr);	close (fd);	if (result == 0)	  return ifr.ifr_index;      }  }#endif  {    struct if_nameindex *idx;    idx = if_nameindex ();    if (idx != NULL)      {	struct if_nameindex *p;	for (p = idx; p->if_index || p->if_name; ++p)	  {	    if (strncmp (p->if_name, ifname, IFNAMSIZ) == 0)	      {		result = p->if_index;		break;	      }	  }	if_freenameindex (idx);      }    return result;  }}voidif_freenameindex (struct if_nameindex *ifn){  struct if_nameindex *ptr = ifn;  if (!ifn) return;  while (ptr->if_name || ptr->if_index)    {      if (ptr->if_name)	free (ptr->if_name);      ++ptr;    }  free (ifn);}struct if_nameindex *if_nameindex (void){#if defined(SIOCGIFCONF)  int fd = socket (AF_INET, SOCK_DGRAM, 0);  struct ifconf ifc;  unsigned int i = 0;  int rq_len, last_len;  struct if_nameindex *idx = NULL;  struct ifreq *ifr, *end, *cur;  if (fd < 0)    return NULL;  /* A first estimate.  */  rq_len = 4 * sizeof (struct ifreq);  ifc.ifc_buf = NULL;  ifc.ifc_len = 0;  /* Read all the interfaces out of the kernel.  */  do    {      last_len = ifc.ifc_len;      ifc.ifc_buf = alloca (ifc.ifc_len = rq_len);      if (ifc.ifc_buf == NULL || ioctl (fd, SIOCGIFCONF, &ifc) < 0)	{	  close (fd);	  return NULL;	}      rq_len *= 2;    }  while (ifc.ifc_len != last_len);  i = 0;  ifr = (struct ifreq *)ifc.ifc_req;  end = (struct ifreq *)((caddr_t)ifr + ifc.ifc_len);  while (ifr < end)    {      int len;#ifdef HAVE_SOCKADDR_SA_LEN#undef MAX#define MAX(a,b)  (((a) > (b)) ? (a) : (b))      len = MAX(sizeof (struct sockaddr), ifr->ifr_addr.sa_len);#else      len = sizeof (struct sockaddr);#endif      cur = ifr;      /* Step along the array by the size of the current structure */      ifr = (struct ifreq *)((caddr_t)ifr + len + IFNAMSIZ);      /* We ignore the other families .. OK ?  */      if (cur->ifr_addr.sa_family != AF_INET)	continue;      /* Make Room safely.  */      {	struct if_nameindex *tidx = NULL;	tidx = realloc (idx, (i + 1) * sizeof(*idx));	if (tidx == NULL)	  {	    if_freenameindex (idx);	    close (fd);	    errno = ENOBUFS;	    return NULL;	  }	idx = tidx;      }      /* FIXME: We did not deal with duplicates or interface aliases.  */      idx[i].if_name = strdup (cur->ifr_name);      if (idx[i].if_name == NULL)	{	  if_freenameindex (idx);	  close (fd);	  errno = ENOBUFS;	  return NULL;	}# if defined(SIOCGIFINDEX)      if (ioctl (fd, SIOCGIFINDEX, cur) >= 0)	idx[i].if_index = cur->ifr_index;      else# endif	idx[i].if_index =  i + 1;      i++;	    }  /* Terminate the array with an empty solt.  */  {    struct if_nameindex *tidx = NULL;    tidx = realloc (idx, (i + 1) * sizeof(*idx));    if (tidx == NULL)      {	if_freenameindex (idx);	close (fd);	errno = ENOBUFS;	return NULL;      }    idx = tidx;  }  idx[i].if_index = 0;  idx[i].if_name = NULL;  close (fd);  return idx;#else  errno = ENOSYS;  return NULL;#endif}char *if_indextoname (unsigned int ifindex, char *ifname){#if defined SIOCGIFNAME  {    int fd = socket (AF_INET, SOCK_DGRAM, 0);    if (fd >= 0)      {	struct ifreq ifr;	ifr.ifr_index = ifindex;	if (ioctl (fd, SIOCGIFNAME, &ifr) == 0)	  {	    close (fd);	    strncpy (ifname, ifr.ifr_name, IFNAMSIZ);	    ifname[IFNAMSIZ - 1] = '\0';	    return ifname;	  }	close (fd);      }  }#else  {    struct if_nameindex *idx;    char *result = NULL;    idx = if_nameindex ();    if (idx != NULL)      {	struct if_nameindex *p;	for (p = idx; p->if_index || p->if_name; ++p)	  {	    if (p->if_index == ifindex)	      {		result = strncpy (ifname, p->if_name, IFNAMSIZ);		result[IFNAMSIZ - 1] = '\0';		break;	      }	  }	if_freenameindex (idx);      }    return result;  }#endif}