static void ip_cmsg_recv_ttl(struct msghdr *msg, struct sk_buff *skb)
{
	int ttl = ip_hdr(skb)->ttl;
	put_cmsg(msg, SOL_IP, IP_TTL, sizeof(int), &ttl);
}
static void ip_cmsg_recv_ttl(struct msghdr *msg, struct sk_buff *skb)
{
	int ttl = ip_hdr(skb)->ttl;
	put_cmsg(msg, SOL_IP, IP_TTL, sizeof(int), &ttl);
}