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/* $OpenBSD: if_nameindex.c,v 1.13 2016/12/16 17:44:59 krw Exp $ */
/* $KAME: if_nameindex.c,v 1.7 2000/11/24 08:17:20 itojun Exp $ */
/*-
* Copyright (c) 2015 Claudio Jeker <claudio@openbsd.org>
* Copyright (c) 1997, 2000
* Berkeley Software Design, Inc. 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.
*
* THIS SOFTWARE IS PROVIDED BY Berkeley Software Design, Inc. ``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 Berkeley Software Design, Inc. 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.
*
* BSDI Id: if_nameindex.c,v 2.3 2000/04/17 22:38:05 dab Exp
*/
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/sysctl.h>
#include <net/if.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
/*
* From RFC 2553:
*
* 4.3 Return All Interface Names and Indexes
*
* The if_nameindex structure holds the information about a single
* interface and is defined as a result of including the <net/if.h>
* header.
*
* struct if_nameindex {
* unsigned int if_index;
* char *if_name;
* };
*
* The final function returns an array of if_nameindex structures, one
* structure per interface.
*
* struct if_nameindex *if_nameindex(void);
*
* The end of the array of structures is indicated by a structure with
* an if_index of 0 and an if_name of NULL. The function returns a NULL
* pointer upon an error, and would set errno to the appropriate value.
*
* The memory used for this array of structures along with the interface
* names pointed to by the if_name members is obtained dynamically.
* This memory is freed by the next function.
*
* 4.4. Free Memory
*
* The following function frees the dynamic memory that was allocated by
* if_nameindex().
*
* #include <net/if.h>
*
* void if_freenameindex(struct if_nameindex *ptr);
*
* The argument to this function must be a pointer that was returned by
* if_nameindex().
*/
struct if_nameindex *
if_nameindex(void)
{
struct if_nameindex_msg *ifnm = NULL;
struct if_nameindex *ifni = NULL, *ifni2;
char *cp;
size_t needed;
unsigned int ni, i;
int mib[6];
mib[0] = CTL_NET;
mib[1] = PF_ROUTE;
mib[2] = 0; /* protocol */
mib[3] = 0; /* not used */
mib[4] = NET_RT_IFNAMES;
mib[5] = 0; /* no flags */
while (1) {
struct if_nameindex_msg *buf = NULL;
if (sysctl(mib, 6, NULL, &needed, NULL, 0) == -1)
goto out;
if (needed == 0)
break;
if ((buf = realloc(ifnm, needed)) == NULL)
goto out;
ifnm = buf;
if (sysctl(mib, 6, ifnm, &needed, NULL, 0) == -1) {
if (errno == ENOMEM)
continue;
goto out;
}
break;
}
/*
* Allocate a chunk of memory, use the first part for the array of
* structures, and the last part for the strings.
*/
ni = needed / sizeof(*ifnm);
ifni = calloc(ni + 1, sizeof(struct if_nameindex) + IF_NAMESIZE);
if (ifni == NULL)
goto out;
cp = (char *)(ifni + (ni + 1));
ifni2 = ifni;
for (i = 0; i < ni; i++) {
ifni2->if_index = ifnm[i].if_index;
/* don't care about truncation */
strlcpy(cp, ifnm[i].if_name, IF_NAMESIZE);
ifni2->if_name = cp;
ifni2++;
cp += IF_NAMESIZE;
}
/* Finally, terminate the array. */
ifni2->if_index = 0;
ifni2->if_name = NULL;
out:
free(ifnm);
return ifni;
}
void
if_freenameindex(struct if_nameindex *ptr)
{
free(ptr);
}
DEF_WEAK(if_nameindex);
DEF_WEAK(if_freenameindex);
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