LWTUNNEL_IP_TTL
[LWTUNNEL_IP_TTL] = { .type = NLA_U8 },
if (tb[LWTUNNEL_IP_TTL])
tun_info->key.ttl = nla_get_u8(tb[LWTUNNEL_IP_TTL]);
nla_put_u8(skb, LWTUNNEL_IP_TTL, tun_info->key.ttl) ||