rtr_aspa
if (len < sizeof(struct rtr_aspa) || (len % 4) != 0)
struct rtr_aspa rtr_aspa;
if (ibuf_get(pdu, &rtr_aspa, sizeof(rtr_aspa)) == -1)
flags = rtr_aspa.hdr.flags;
needle.as = ntohl(rtr_aspa.cas);
aspa->as = ntohl(rtr_aspa.cas);