IP ID check (flush_id) in inet_gro_receive is necessary or notï

From: Tan Xiaojun
Date: Tue Jun 28 2016 - 00:40:38 EST


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.