Subject: IP ID check (flush_id) in inet_gro_receive is necessary or not？

From: Tan Xiaojun <[email-masked]>
Date: Tue, 28 Jun 2016 12:40:01 +0800

Hi everyone,

	I'm sorry to bother you. But I was confused.

	The IP ID check (flush_id) in inet_gro_receive is only used by tcp_gro_receive, and in tcp_gro_receive we have tcphdr check to ensure the order of skbs,
	like below:

	flush |= (__force int)(th->ack_seq ^ th2->ack_seq);
	flush |= (ntohl(th2->seq) + skb_gro_len(p)) ^ ntohl(th->seq);

	So if I remove the IP ID check in inet_gro_receive, there will be a problem ? And under what circumstances ?

Thanks.
Xiaojun.