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/*
* Copyright (c) 1998-1999, Craig Metz, 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. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Craig Metz and
* by other contributors.
* 4. Neither the name of the author nor the names of 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 <sys/types.h>
#include <stdlib.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/if_dl.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
unsigned int
if_nametoindex(const char *name)
{
int i, fd = -1, extra, len = 0;
struct ifconf ifconf;
char lastname[IFNAMSIZ], *thisname, *inbuf;
unsigned int index = 0;
struct sockaddr *sa;
void *p;
ifconf.ifc_buf = 0;
if ((fd = socket(PF_INET, SOCK_DGRAM, 0)) < 0)
goto ret;
/*
* Try ifc_len == 0 hack first, to get the actual length.
* If that fails, revert to a loop which grows the ifc_buf
* until it is sufficiently large.
*/
extra = sizeof(struct ifreq);
while (1) {
ifconf.ifc_len = len;
if (ioctl(fd, SIOCGIFCONF, (void *) &ifconf) == -1 &&
ifconf.ifc_buf)
goto ret;
if (ifconf.ifc_buf &&
ifconf.ifc_len + extra < len)
break;
if (ifconf.ifc_buf) {
if (len == 0)
len = 4096;
ifconf.ifc_len = len *= 2;
} else {
len = ifconf.ifc_len;
extra = 0;
}
inbuf = realloc(ifconf.ifc_buf, ifconf.ifc_len);
if (inbuf == NULL)
goto ret;
ifconf.ifc_buf = inbuf;
}
i = 0;
p = ifconf.ifc_buf;
len = ifconf.ifc_len;
lastname[0] = 0;
lastname[sizeof(lastname)-1] = 0;
while (len > 0) {
if (len < IFNAMSIZ + sizeof(struct sockaddr))
goto ret;
thisname = p;
if (strncmp(lastname, p, IFNAMSIZ)) {
if (!strcmp(lastname, name)) {
index = i;
goto ret;
}
memcpy(lastname, thisname, IFNAMSIZ);
i++;
}
len -= IFNAMSIZ;
p += IFNAMSIZ;
sa = (struct sockaddr *)p;
if (!strncmp(thisname, name, IFNAMSIZ) &&
sa->sa_family == AF_LINK) {
struct sockaddr_dl *sd = p;
index = sd->sdl_index;
goto ret;
}
if (len < sa->sa_len)
goto ret;
len -= sa->sa_len;
p += sa->sa_len;
}
if (!strcmp(lastname, name))
index = i;
ret:
if (fd != -1)
close(fd);
if (ifconf.ifc_buf)
free(ifconf.ifc_buf);
return index;
}
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