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/* darkstat 3
* copyright (c) 2001-2008 Emil Mikulic.
*
* localip.c: determine local IP of our capture interface
*
* You may use, modify and redistribute this file under the terms of the
* GNU General Public License version 2. (see COPYING.GPL)
*/
#include "darkstat.h"
#include "conv.h" /* for strlcpy */
#include "decode.h" /* for ip_to_str */
#include "err.h"
#include "localip.h"
#ifdef HAVE_SYS_SOCKIO_H
# include <sys/sockio.h> /* for SIOCGIFADDR, especially on Solaris */
#endif
#include <sys/socket.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <errno.h>
#include <string.h>
#include <unistd.h>
static const char *iface = NULL;
in_addr_t localip = 0;
static in_addr_t last_localip = 0;
void
localip_init(const char *interface)
{
iface = interface;
localip_update();
}
void
localip_update(void)
{
int tmp = socket(AF_INET, SOCK_DGRAM, IPPROTO_IP);
struct ifreq ifr;
struct sockaddr sa;
if (iface == NULL) {
/* reading from capfile */
localip = 0;
return;
}
strlcpy(ifr.ifr_name, iface, IFNAMSIZ);
ifr.ifr_addr.sa_family = AF_INET;
if (ioctl(tmp, SIOCGIFADDR, &ifr) == -1) {
if (errno == EADDRNOTAVAIL) {
/* lost IP, e.g. ifconfig eth0 delete, don't die */
localip = 0;
close(tmp);
return;
} else
err(1, "can't get own IP address on interface \"%s\"", iface);
}
close(tmp);
sa = ifr.ifr_addr;
/* struct sockaddr {
* sa_family_t sa_family; * address family, AF_xxx
* char sa_data[14]; * 14 bytes of protocol address
*
* struct sockaddr_in {
* sa_family_t sin_family; * Address family
* unsigned short int sin_port; * Port number
* struct in_addr sin_addr; * Internet address
*
* struct in_addr {
* __u32 s_addr;
*/
localip = ((struct sockaddr_in*)&sa)->sin_addr.s_addr;
if (last_localip != localip) {
verbosef("local_ip update(%s) = %s", iface, ip_to_str(localip));
last_localip = localip;
}
}
/* vim:set ts=3 sw=3 tw=78 expandtab: */
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