rts_copyfromsockaddr
size = rts_copyfromsockaddr(sa, dst_addrp);
size = rts_copyfromsockaddr(sa, gw_addrp);
size = rts_copyfromsockaddr(sa, net_maskp);
size = rts_copyfromsockaddr(sa, in_src_addrp);
size = rts_copyfromsockaddr(sa, if_addrp);
size = rts_copyfromsockaddr(sa, authorp);
static size_t rts_copyfromsockaddr(struct sockaddr *sa, in6_addr_t *addrp);