lsa_find_rtr_frag
struct vertex *lsa_find_rtr_frag(struct area *, u_int32_t, unsigned int);
return lsa_find_rtr_frag(area, rtr_id, 0);
v = lsa_find_rtr_frag(v->area, htonl(v->adv_rtr), n++);
v = lsa_find_rtr_frag(v->area, htonl(v->adv_rtr), frag++);