) {     struct ip_header *ip;     unsigned int IP_header_length;     packet += sizeof(struct ether_header);     capture_len -= sizeof(struct ether_header);     ip = (struct ip_header*) packet;     IP_header_length = ip->vhl * 0; /* ip_hl is in 0-byte words */     char *sinfo = strdup(inet_ntoa(ip->src));     char *dinfo = strdup(inet_ntoa(ip->dst));     printf ("%s<-__->%s\n", sinfo ,dinfo);     free (sinfo);     free (dinfo); }  