BPF compiler using libpcap

pcapbpfc.c

#include <pcap.h>
#include <unistd.h>

int main(int argc, char **argv)
{
        struct bpf_program bpfprog;
        int dflag = 0;
        int c;

        while ((c = getopt(argc, argv, "d")) != -1) {
                switch (c) {
                case 'd':
                        dflag++;
                        break;
                default:
                        fprintf(stderr, "Usage: %s [-d|-dd|-ddd] filter\n", argv[0]);
                        return 1;
                }
        }

        if (pcap_compile_nopcap(1, 0, &bpfprog, argv[optind], 0, 0) < 0) {
                fprintf(stderr, "pcap_compile_nopcap()\n");
                return 1;
        }

        bpf_dump(&bpfprog, dflag);

        return 0;
}