sbappendaddrchain
ok = sbappendaddrchain(&so->so_rcv, (struct sockaddr *)&key_src, n,
ok = sbappendaddrchain(&so->so_rcv, (struct sockaddr *)&key_src, n,
ok = sbappendaddrchain(&rp->rcb_socket->so_rcv,
int sbappendaddrchain(struct sockbuf *, const struct sockaddr *,