PFR_A_ADDR
snl_add_msg_attr_ip6(nw, PFR_A_ADDR, &addr->pfra_ip6addr);
{ .type = PFR_A_ADDR, .off = _OUT(pfra_ip6addr), .cb = snl_attr_get_in6_addr },
{ .type = PFR_A_ADDR, .off = _OUT(pfra_u), .cb = nlattr_get_in6_addr },
nlattr_add_in6_addr(nw, PFR_A_ADDR, &a->pfra_u._pfra_ip6addr);