NFNLA_HOOK_HOOKNUM
ret = nla_put_be32(nlskb, NFNLA_HOOK_HOOKNUM, htonl(hooknum));
[NFNLA_HOOK_HOOKNUM] = { .type = NLA_U32 },
hooknum = ntohl(nla_get_be32(nla[NFNLA_HOOK_HOOKNUM]));
if (!nla[NFNLA_HOOK_HOOKNUM])