text: /*	$KAME: ifname.c,v 1.4 2001/08/20 02:32:40 itojun Exp $	*/
  
  /*
   * Copyright (C) 1995, 1996, 1997, and 1998 WIDE Project.
   * 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 project 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 PROJECT 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 PROJECT 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 <sys/cdefs.h>
  #include <sys/types.h>
  #include <sys/types.h>
  
  /*
   * TODO:
   * - prototype defs into arpa/inet.h, not net/if.h (bsd-api-new-02)
   */
  
  #include <sys/param.h>
  #include <sys/socket.h>
  #include <sys/sockio.h>
  #include <sys/sysctl.h>
  #include <net/if.h>
  #include <net/route.h>
  #include <net/if_dl.h>
  
  #include <unistd.h>
  #include <errno.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define ROUNDUP(a) \
  	((a) > 0 ? (1 + (((a) - 1) | (sizeof(long) - 1))) : sizeof(long))
  #define ADVANCE(x, n)
  
  static unsigned int
  if_onametoindex(ifname)
  	const char *ifname;
  {
  	struct if_nameindex *iff = if_nameindex(), *ifx;
  	int ret;
  
  	if (iff == NULL) return 0;
  	ifx = iff;
  	while (ifx->if_name != NULL) {
  		if (strcmp(ifx->if_name, ifname) == 0) {
  			ret = ifx->if_index;
  			if_freenameindex(iff);
  			return ret;
  		}
  		ifx++;
  	}
  	if_freenameindex(iff);
  	errno = ENXIO;
  	return 0;
  }
   
  unsigned int
  if_nametoindex(ifname)
  	const char *ifname;
  {
  	int s;
  	struct ifreq ifr;
  
  	s = socket(AF_INET, SOCK_DGRAM, 0);
  	if (s == -1)
  		return (0);
  	strlcpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
  	if (ioctl(s, SIOCGIFINDEX, &ifr) == -1) {
  		close (s);
  		return (if_onametoindex(ifname));
  	}
  	close(s);
  	return (ifr.ifr_index);
  }
  
  char *
  if_indextoname(ifindex, ifname)
  	unsigned int ifindex;
  	char *ifname; /* at least IF_NAMESIZE */
  {
  	struct if_nameindex *iff = if_nameindex(), *ifx;
  	char *cp, *dp;
  
  	if (iff == NULL) return NULL;
  	ifx = iff;
  	while (ifx->if_index != 0) {
  		if (ifx->if_index == ifindex) {
  			cp = ifname;
  			dp = ifx->if_name;
  			while ((*cp++ = *dp++)) ;
  			if_freenameindex(iff);
  			return (ifname);
  		}
  		ifx++;
  	}
  	if_freenameindex(iff);
  	errno = ENXIO;
  	return NULL;
  }
  
  struct if_nameindex *
  if_nameindex()
  {
  	size_t needed;
  	int mib[6], i, ifn = 0, off = 0, hlen;
  	char *buf = NULL, *lim, *next, *cp, *ifbuf = NULL;
  	struct rt_msghdr *rtm;
  	struct if_msghdr *ifm;
  	struct sockaddr *sa;
  	struct if_nameindex *ret = NULL;
  	static int ifxs = 64;	/* initial upper limit */
  	struct _ifx {
  		int if_index;
  		int if_off;
  	} *ifx = NULL;
  
  	mib[0] = CTL_NET;
  	mib[1] = PF_ROUTE;
  	mib[2] = 0;		/* protocol */
  	mib[3] = 0;		/* wildcard address family */
  	mib[4] = 0;
  	mib[5] = 0;		/* no flags */
  	if (__sysctl(mib, 6, NULL, &needed, NULL, 0) < 0)
  		return NULL;
  	if ((buf = malloc(needed)) == NULL) {
  		errno = ENOMEM;
  		goto end;
  	}
  	/* XXX: we may have allocated too much than necessary */
  	if ((ifbuf = malloc(needed)) == NULL) {
  		errno = ENOMEM;
  		goto end;
  	}
  	if ((ifx = (struct _ifx *)malloc(sizeof(*ifx) * ifxs)) == NULL) {
  		errno = ENOMEM;
  		goto end;
  	}
  	if (__sysctl(mib, 6, buf, &needed, NULL, 0) < 0) {
  		/* sysctl has set errno */
  		goto end;
  	}
  	lim = buf + needed;
  	for (next = buf; next < lim; next += rtm->rtm_msglen) {
  		rtm = (struct rt_msghdr *)next;
  		if (rtm->rtm_version != RTM_VERSION) {
  			errno = EPROTONOSUPPORT;
  			goto end;
  		}
  		switch (rtm->rtm_type) {
  		case RTM_IFINFO:
  			ifm = (struct if_msghdr *)rtm;
  			ifx[ifn].if_index = ifm->ifm_index;
  			ifx[ifn].if_off = off;
  			cp = (char *)(ifm + 1);
  			for (i = 1; i; i <<= 1) {
  				if (i & ifm->ifm_addrs) {
  					sa = (struct sockaddr *)cp;
  					ADVANCE(cp, sa);
  				}
  			}
  			if (++ifn == ifxs) {
  				/* we need more memory */
  				struct _ifx *newifx;
  
  				ifxs *= 2;
  				if ((newifx = (struct _ifx *)malloc(sizeof(*newifx) * ifxs)) == NULL) {
  					errno = ENOMEM;
  					goto end;
  				}
  
  				/* copy and free old data */
  				memcpy(newifx, ifx, (sizeof(*ifx) * ifxs) / 2);
  				free(ifx);
  				ifx = newifx;
  			}
  		}
  	}
  	hlen = sizeof(struct if_nameindex) * (ifn + 1);
  	if ((cp = (char *)malloc(hlen + off)) == NULL) {
  		errno = ENOMEM;
  		goto end;
  	}
  	bcopy(ifbuf, cp + hlen, off);
  	ret = (struct if_nameindex *)cp;
  	for (i = 0; i < ifn; i++) {
  		ret[i].if_index = ifx[i].if_index;
  		ret[i].if_name = cp + hlen + ifx[i].if_off;
  	}
  	ret[ifn].if_index = 0;
  	ret[ifn].if_name = NULL;
  
    end:
  	if (buf) free(buf);
  	if (ifbuf) free(ifbuf);
  	if (ifx) free(ifx);
  
  	return ret;
  }
  
  void if_freenameindex(ptr)
  	struct if_nameindex *ptr;
  {
  	free(ptr);
  }
  