跪求解决嗅探问题
...我自己网上找了个代码,,..用来分析有所经过网卡的IP数据包,,
但不知道怎么的老是收不到包,就是在read那里阻塞住了,,,,,,,,很奇怪,搞了一天了...郁闷死了,,=   =我用freebsd的,,,,,,....先谢谢了...
代码如下:
#define   INTERFACE   "vr0 "  

int   bytes_recieved   =   0;

int   Open_Raw_Socket(void);
int   Set_Promisc(char   *interface,   int   sock);
static   void
sig_alrm(int   signo)
{
printf( "alrm.bytes_recieved   :%d...\n ",   bytes_recieved);
alarm(2);
}


int   main()  
{

int   sock,   bytes_recieved;
char   buffer[2048];
memset(buffer,   0,   2048);

struct   ip   *iptemp;
struct   tcphdr   *tcptemp;

sock   =   Open_Raw_Socket();
Set_Promisc(INTERFACE,   sock);

#if   1
/*alarm   time*/
if   (signal(SIGALRM,   sig_alrm)   ==   SIG_ERR)
{
exit(1);
}

alarm(2);
#endif

while(1)
{
printf( "waiting   data:\n ");
bytes_recieved   =   read(sock,   buffer,     sizeof(buffer));


//printf( "recived   %d\n ",   bytes_recieved);

if(bytes_recieved   <=   0)
{
continue;
}


iptemp   =   (struct   ip   *)buffer;

#if   0
/*See   if   this   is   a   TCP   packet*/
if(iptemp-> ip_p   ==   6)
  {
printf( "IP   header   length   :::%d\n ",   iptemp-> ip_hl);
printf( "Protocol   :::%d\n ",   iptemp-> ip_p);
tcptemp   =   (struct   tcphdr   *)(buffer   +   (4*iptemp-> ip_len));
printf( "Source   port   :::%d\n ",   ntohs(tcptemp-> th_sport));
printf( "Dest   port   :::%d\n ",   ntohs(tcptemp-> th_dport));  
}
#endif

}
}

int   Open_Raw_Socket(void)  
{
int   sock;
if((sock   =   socket(PF_INET,   SOCK_RAW,   0))   <   0)
{
/*Then   the   socket   was   not   created   properly   and   must   die*/
perror( "The   raw   socket   was   not   created ");
exit(0);
};

return(sock);
}

int   Set_Promisc(char   *interface,   int   sock   )  
{
struct   ifreq   ifr;
memset(&ifr,   0,   sizeof(struct   ifreq));
strncpy(ifr.ifr_name,   interface,strlen(interface)+1);

if((ioctl(sock,   SIOCGIFFLAGS,   &ifr)   ==   -1))
{
/*Could   not   retrieve   flags   for   the   interface*/
perror( "Could   not   retrive   flags   for   the   interface ");
exit(0);
}

printf( "The   interface   is   :::   %s\n ",   interface);
printf( "Retrieved   flags   from   interface   successfully\n ");

ifr.ifr_flags   |=   IFF_PROMISC;
if   (ioctl   (sock,   SIOCSIFFLAGS,   &ifr)   ==   -1   )
{
/*Could   not   set &nb