reghost(iadd);
intohost(iadd,hn);
if(strlen(hn)>0)
printf("%s",hn);
else{
for(i=0;i<3;++i)
printf("%d:",ipadd[i]);
printf("%d:",ipadd[i]);
}
}

//main
//the start and configure of getting packet
int main(int argc,char **argv)
{
char ebuf[PCAP_ERRBUF_SIZE];
pcap_t *pd;

if(argc<=1){
printf("usage:%s \n",argv[0]);
exit(0);
}

/*configure using pcap*/
if((pd=pcap_open_live(argv[1],DEFAULT_SNAPLEN,1,1000,ebuf))==NULL)
{
(void)fprintf(stderr,"%s",ebuf);
exit(1);
}

/*get the packet by the pcap_loop*/
if(pcap_loop(pd,-1,packet_print,NULL)<0){
(void)fprintf(stderr,"pcap_loop:%s\n",pcap_geterr(pd));
exit(1);
}
pcap_close(pd);
exit(0);
}