RTFLAG
RTFLAG("U", RTF_UP);
RTFLAG("G", RTF_GATEWAY);
RTFLAG("H", RTF_HOST);
RTFLAG("R", RTF_REJECT);
RTFLAG("D", RTF_DYNAMIC);
RTFLAG("M", RTF_MODIFIED);
RTFLAG("d", RTF_DONE);
RTFLAG("m", RTF_MULTICAST);
RTFLAG("C", RTF_CLONING);
RTFLAG("c", RTF_CLONED);
RTFLAG("L", RTF_LLINFO);
RTFLAG("S", RTF_STATIC);
RTFLAG("B", RTF_BLACKHOLE);
RTFLAG("3", RTF_PROTO3);
RTFLAG("2", RTF_PROTO2);
RTFLAG("1", RTF_PROTO1);
RTFLAG("b", RTF_BROADCAST);