Linux下几例抓包程序代码

抓包程序1 grub_allpacket.c
#include <stdio.h>
#include <string.h>
#include <errno.h> 
#include <unistd.h>
#include <sys/socket.h>
#include <sys/types.h> 
#include <linux/in.h>
#include <linux/if_ether.h>
#include <net/if.h>
#include <sys/ioctl.h>
#include <stdlib.h>
int main(int argc, char **argv) {
   int sock, n,i;
   char buffer[2048];
   unsigned char *iphead, *ethhead;
   struct ifreq ethreq;
 
   if ( (sock=socket(PF_PACKET, SOCK_RAW,
                     htons(ETH_P_IP)))<0) {
     perror("socket");
     exit(1);
   }
   /* Set the network card in promiscuos mode */
   strncpy(ethreq.ifr_name,"eth0",IFNAMSIZ);
   if (ioctl(sock,SIOCGIFFLAGS,&ethreq)==-1) {
     perror("ioctl");
     close(sock);
     exit(1);
}
   ethreq.ifr_flags|=IFF_PROMISC;
   if (ioctl(sock,SIOCSIFFLAGS,&ethreq)==-1) {
     perror("ioctl");
     close(sock);
     exit(1);
   }
 
   while (1) {
     printf("----------\n");
     n = recvfrom(sock,buffer,2048,0,NULL,NULL);
     printf("%d bytes read\n",n);
     printf("the frame content is :\n");
     for(i=0;i<n;)
 {
 printf("%02x",(unsigned char)buffer[i]);
 fflush(stdout);
 i=i+1;
 if(i%8==0)
  printf("\n");
 else
  printf(":");
 }
     printf("\n");
     /* Check to see if the packet contains at least
&nbs