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/*
*
* Connection Manager
*
* Copyright (C) 2007-2010 Intel Corporation. All rights reserved.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* 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 St, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#define _GNU_SOURCE
#include <stdio.h>
#include <errno.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>
#include <sys/poll.h>
#include <sys/ioctl.h>
#include <netinet/in.h>
#include <netinet/ip.h>
#include <net/ethernet.h>
#include <net/if.h>
#include <net/if_arp.h>
#include <linux/if_tun.h>
static int inet_ifup(const char *ifname)
{
struct ifreq ifr;
int sk, err;
sk = socket(PF_INET, SOCK_DGRAM | SOCK_CLOEXEC, 0);
if (sk < 0)
return -errno;
memset(&ifr, 0, sizeof(ifr));
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(sk, SIOCGIFFLAGS, &ifr) < 0) {
err = -errno;
goto done;
}
if (ifr.ifr_flags & IFF_UP) {
err = -EALREADY;
goto done;
}
ifr.ifr_flags |= IFF_UP;
if (ioctl(sk, SIOCSIFFLAGS, &ifr) < 0) {
err = -errno;
goto done;
}
err = 0;
done:
close(sk);
return err;
}
static int create_tap(const char *ifname)
{
struct ifreq ifr;
int fd, val;
fd = open("/dev/net/tun", O_RDWR | O_CLOEXEC);
if (fd < 0) {
perror("Failed to open TUN/TAP device");
return -1;
}
memset(&ifr, 0, sizeof(ifr));
ifr.ifr_flags = IFF_TAP | IFF_NO_PI;
strncpy(ifr.ifr_name, ifname, sizeof(ifr.ifr_name));
if (ioctl(fd, TUNSETIFF, (void *) &ifr) < 0) {
perror("Failed to set TUN/TAP interface");
close(fd);
return -1;
}
val = ARPHRD_ETHER;
if (ioctl(fd, TUNSETLINK, (unsigned long) val) < 0)
perror("Failed to set TUN/TAP link type");
return fd;
}
static void dump_packet(unsigned char *buf, int len)
{
int i;
printf("[");
for (i = 0; i < len; i++) {
printf(" %02x", buf[i]);
if ((i + 1) % 16 == 0)
printf("\n ");
else if ((i + 1) % 8 == 0)
printf(" ");
}
printf(" ]\n");
}
static void decode_ip(unsigned char *buf, int len)
{
struct iphdr *ip = (void *) buf;
printf(" IP proto %d saddr 0x%08x daddr 0x%08x\n",
ip->protocol, ip->saddr, ip->daddr);
}
static void decode_packet(unsigned char *buf, int len)
{
struct ether_header *eh = (void *) buf;
char src[18], dst[18];
uint16_t type;
snprintf(dst, sizeof(dst), "%02x:%02x:%02x:%02x:%02x:%02x",
eh->ether_dhost[0], eh->ether_dhost[1],
eh->ether_dhost[2], eh->ether_dhost[3],
eh->ether_dhost[4], eh->ether_dhost[5]);
snprintf(src, sizeof(src), "%02x:%02x:%02x:%02x:%02x:%02x",
eh->ether_shost[0], eh->ether_shost[1],
eh->ether_shost[2], eh->ether_shost[3],
eh->ether_shost[4], eh->ether_shost[5]);
type = ntohs(eh->ether_type);
printf("> type 0x%04x src %s dst %s <\n", type, src, dst);
switch (type) {
case ETHERTYPE_IP:
decode_ip(buf + 14, len - 14);
break;
case ETHERTYPE_LOOPBACK:
dump_packet(buf, len);
break;
}
}
int main(int argc, char *argv[])
{
const char *ifname = "xxx";
struct pollfd p;
int fd;
fd = create_tap(ifname);
if (fd < 0)
return 1;
if (inet_ifup(ifname) < 0) {
close(fd);
return 1;
}
memset(&p, 0, sizeof(p));
p.fd = fd;
p.events = POLLHUP | POLLIN;
while (1) {
unsigned char buf[2048];
int len;
len = poll(&p, 1, -1);
if (len < 0)
break;
if (len == 0)
continue;
len = read(fd, buf, sizeof(buf));
if (len < 0)
break;
decode_packet(buf, len);
}
return 0;
}
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