TCA_NAT_PARMS
if (nla_put(skb, TCA_NAT_PARMS, sizeof(opt), &opt))
[TCA_NAT_PARMS] = { .len = sizeof(struct tc_nat) },
if (tb[TCA_NAT_PARMS] == NULL)
parm = nla_data(tb[TCA_NAT_PARMS]);