Linux下使用混杂模式抓包

核心提示： 有时候不光要抓自己的包，还要抓目的地是其他网卡的包，Linux下使用混杂模式抓包，及时过路包，这时候就要将监听网卡设为混在模式#include <stdio.h>#include <stdlib.h>#include <string.h>#include <sys/socke

 有时候不光要抓自己的包，还要抓目的地是其他网卡的包，及时过路包，这时候就要将监听网卡设为混在模式

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <linux/if_ether.h>
#include <sys/ioctl.h>
#include <net/if.h>
#include <net/ethernet.h>

/**
* Set misc mode for interface
* \param if_name interface name we will set
* \param sockfd the socket id we will set
* */
int set_promisc (char *if_name, int sockfd)
{
struct ifreq ifr;

strcpy (ifr.ifr_name, if_name);
if (0 != ioctl (sockfd, SIOCGIFFLAGS, &ifr))
{
printf ("Get interface flag failed\n");
return -1;
}

/* add the misc mode */
ifr.ifr_flags |= IFF_PROMISC;

if (0 != ioctl (sockfd, SIOCSIFFLAGS, &ifr))
{
printf ("Set interface flag failed\n");
return -1;
}
}

int main (int argc, char *argv[])
{
int sockfd;
int ret = 0;
char buffer[1518] = {0};
char *eth_head = NULL;

if ((sockfd = socket (PF_PACKET, SOCK_RAW, htons (ETH_P_ALL))) < 0)
{
printf ("create socket failed\n");
return -1;
}

if (0 != set_promisc ("eth0", sockfd))
{
printf ("Failed to set interface promisc mode\n");
}

while (1)
{
memset (buffer, 0x0, sizeof (buffer));
ret = recvfrom (sockfd, buffer, sizeof (buffer), 0, NULL, NULL);
printf ("recview package length : %d\n", ret);

eth_head = buffer;
printf ("PACKAGE START\n");
/* get source and dectination mac address */
printf ("dectination mac:%02x-%02x-%02x-%02x-%02x-%02x,"
"source mac:%02x-%02x-%02x-%02x-%02x-%02x;\n", eth_head[0],
eth_head[1], eth_head[2], eth_head[3], eth_head[4],
eth_head[5], eth_head[6], eth_head[7], eth_head[8],
eth_head[9], eth_head[10], eth_head[11]);
printf ("eth_type:%02x%02x\n", eth_head[12], eth_head[13]);

/* ARP proptocol flag */
if (0x08 == eth_head[12] && 0x06 == eth_head[13])
{
printf ("ARP source ip:%d.%d.%d.%d,destination ip:%d.%d.%d.%d;\n",
eth_head[28], eth_head[29], eth_head[30], eth_head[31],
eth_head[38], eth_head[39], eth_head[40], eth_head[41]);
}
/* IPv4 proptocol flag */
else if (0x08 == eth_head[12] && 0x00 == eth_head[13])
{
if (0x45 == eth_head[14])
{
printf ("IPv4 source ip:%d.%d.%d.%d,destination ip:%d.%d.%d."
"%d;\n", eth_head[26], eth_head[27], eth_head[28],
eth_head[29], eth_head[30], eth_head[31],
eth_head[32], eth_head[33]);
}
else
{
printf ("p_head:%02x\n", eth_head[14]);
}
}
printf ("PACKAGE END\n");
}

return 0;
}