main.c

ip数据包截获

#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#include<sys/socket.h>
#include<sys/types.h>
#include<sys/ioctl.h>
#include<netinet/if_ether.h>
#include<netdb.h>
#include<net/ethernet.h>
#include<net/if.h>
#include<signal.h>
#include<sys/wait.h>
#include<unistd.h>                                                              
void handler(int signo){
    int pid;
    while((pid=wait(NULL))!=-1) ;
}
int main()
{
    int sock, i=0, id, bytes;
    int fromlen;
    struct sockaddr_in from;
    char url[100], dns[100], buffer[65535];
    signal(SIGCHLD,handler);
    sock=set_promisc();
    fromlen = sizeof(from);
    while (1) {
	if ((bytes = recvfrom(sock, buffer, sizeof(buffer), 0,
			      (struct sockaddr *) &from, &fromlen)) < 0)
	    perror("recvfrom\n");
	id = fork();
	if (id == 0) {
	    i = intercept(buffer, dns);
	    exit(0);
	} else if (id == -1)
	    perror("fork");
	else;
    }
    close(sock);
    return 0;
}