[완료]libpcap 프로그래밍 공부중인데요.

...
 /* Compiles the filter expression into a BPF filter program */
 if ( pcap_compile(descr, &filter, "(tcp[13] == 0x10) or (tcp[13] == 0x18)", 1, mask) == -1){
    fprintf(stderr, "Error in pcap_compile(): %s\n", pcap_geterr(descr) );
    exit(1);
 }
 
 /* Load the filter program into the packet capture device. */
 if( pcap_setfilter(descr,&filter) == -1 ){
    fprintf(stderr, "Error in pcap_setfilter(): %s\n", pcap_geterr(descr));
    exit(1);
 }