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/* arping/src/findif_getifaddrs.c
*
* Copyright (C) 2000-2014 Thomas Habets <thomas@habets.se>
*
* 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.
*/
/**
* Most modern systems should have getifaddrs().
*/
#if HAVE_CONFIG_H
#include "config.h"
#endif
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <ifaddrs.h>
#include <net/if.h>
#include <netinet/in.h>
#if HAVE_LIBNET_H
#include <libnet.h>
#endif
#include "arping.h"
#define UNUSED(x) (void)(x)
const char *
arping_lookupdev(uint32_t srcip,
uint32_t dstip,
char *ebuf)
{
struct ifaddrs *ifa = NULL;
struct ifaddrs *cur;
const char *ret = NULL;
int match_count = 0; /* Matching interfaces */
UNUSED(srcip);
/* best match */
in_addr_t best_mask = 0;
/* Results */
static char ifname[IFNAMSIZ];
*ebuf = 0;
if (getifaddrs(&ifa)) {
if (verbose) {
printf("arping: getifaddrs(): %s\n", strerror(errno));
}
snprintf(ebuf, LIBNET_ERRBUF_SIZE,
"getifaddrs(): %s", strerror(errno));
goto out;
}
for (cur = ifa; cur; cur = cur->ifa_next) {
in_addr_t addr, mask;
if (!(cur->ifa_flags & IFF_UP)) {
continue;
}
if (!cur->ifa_addr
|| !cur->ifa_netmask
|| !cur->ifa_name) {
continue;
}
if (cur->ifa_addr->sa_family != AF_INET) {
continue;
}
if (cur->ifa_flags & (IFF_LOOPBACK|IFF_POINTOPOINT)) {
continue;
}
addr =((struct sockaddr_in*)cur->ifa_addr)->sin_addr.s_addr;
mask =((struct sockaddr_in*)cur->ifa_netmask)->sin_addr.s_addr;
if ((addr & mask) != (dstip & mask)) {
continue;
}
match_count++;
if (ntohl(mask) > ntohl(best_mask)) {
memset(ifname, 0, sizeof(ifname));
strncpy(ifname, cur->ifa_name, sizeof(ifname)-1);
best_mask = mask;
}
}
if (match_count) {
ret = ifname;
if (verbose) {
printf("arping: Autodetected interface %s\n", ret);
}
} else {
if (verbose > 1) {
printf("arping: Failed to find iface using"
" getifaddrs().\n");
}
snprintf(ebuf, LIBNET_ERRBUF_SIZE,
"No matching interface found using getifaddrs().");
}
out:
if (ifa) {
freeifaddrs(ifa);
}
return ret;
}
/* ---- Emacs Variables ----
* Local Variables:
* c-basic-offset: 8
* indent-tabs-mode: nil
* End:
*/
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