和我一起学libpcap(2)

#ifdef __cplusplus
extern "C" {
#endif
#include 
#ifdef __cplusplus
}
#endif
void printer(u_char * user, const struct pcap_pkthdr 
* h, const u_char * p)
{
printf("I get one packet! ");
/* 哈哈,我都想喝一杯庆祝一下了! */
}
#define DEFAULT_SNAPLEN 68
/* 别问我为什么是68,我从tcpdump看来的 */
int main()
{
        char ebuf[PCAP_ERRBUF_SIZE];
        char *device = pcap_lookupdev(ebuf);
        bpf_u_int32 localnet, netmask;
        pcap_lookupnet(device, &localnet, &netmask, ebuf);
        printf("%u.%u.%u.%u", localnet&0xff, localnet>>8&0xff,
                localnet>>16&0xff, localnet>>24&0xff);
        printf(":%d.%d.%d.%d ", netmask&0xff, netmask>>8&0xff,
                netmask>>16&0xff, netmask>>24&0xff);
        struct pcap_t *pd = pcap_open_live(device, 
	DEFAULT_SNAPLEN, 0, 1000, ebuf);
        if(pcap_datalink(pd) == DLT_EN10MB)
                printf("10Mb以太网 ");
        struct bpf_program fcode;
        pcap_compile(pd, &fcode, NULL, 1, 0);
        pcap_setfilter(pd, &fcode);
        pcap_loop(pd, 10, printer, NULL);
        struct pcap_stat stat;
        pcap_stats(pd, &stat);
        printf("recv %d, drop %d. ", stat.ps_recv, stat.ps_drop);
        pcap_close(pd);
}
#gcc p.cxx -lpcap
#./a.out
166.111.168.0:255.255.252.0
10Mb以太网
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
I get one packet!
recv 10, drop 0.
#