DLT_RAW
bpfattach(&ifp->if_bpf, ifp, DLT_RAW, 0);
bpf_attach(ifp, DLT_RAW, 0);
ifp->if_dlt = DLT_RAW;
ifp->if_dlt = DLT_RAW;
bpf_attach(ifp, DLT_RAW, 0);
bpf_attach(ifp, DLT_RAW, 0);
sc->intf.if_dlt = DLT_RAW;
pd = pcap_open_dead(DLT_RAW, maxsnaplen);