NFNLA_HOOK_HOOKNUM
ret = nla_put_be32(nlskb, NFNLA_HOOK_HOOKNUM, htonl(hooknum));
[NFNLA_HOOK_HOOKNUM] = NLA_POLICY_MAX(NLA_BE32, 255),
hooknum = ntohl(nla_get_be32(nla[NFNLA_HOOK_HOOKNUM]));
if (!nla[NFNLA_HOOK_HOOKNUM])