CGW_DST_IF
if (!tb[CGW_SRC_IF] || !tb[CGW_DST_IF])
ccgw->dst_idx = nla_get_u32(tb[CGW_DST_IF]);
if (nla_put_u32(skb, CGW_DST_IF, gwj->ccgw.dst_idx) < 0)
[CGW_DST_IF] = { .type = NLA_U32 },