netdev - Re: [PATCH net-next 0/2] net: fix flowlabel inconsistency in reset packet

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Date:   Sun, 19 Nov 2017 12:26:49 +0900 (KST)
From:   David Miller <davem@...emloft.net>
To:     shli@...nel.org
Cc:     netdev@...r.kernel.org, kafai@...com, eric.dumazet@...il.com,
        flo@...rcot.fr, xiyou.wangcong@...il.com, tom@...bertland.com,
        Kernel-team@...com, shli@...com
Subject: Re: [PATCH net-next 0/2] net: fix flowlabel inconsistency in reset
 packet

From: Shaohua Li <shli@...nel.org>
Date: Fri, 17 Nov 2017 10:24:49 -0800

> From: Shaohua Li <shli@...com>
> 
> Hi,
> 
> Please see below tcpdump output:
...
> The tcp reset packet has a different flowlabel, which causes our router
> doesn't correctly close tcp connection. We are using flowlabel to do
> load balance. Routers in the path maintain connection state. So if flow
> label changes, the packet is routed through a different router. In this
> case, the old router doesn't get the reset packet to close the tcp
> connection.
> 
> The reason is the normal packet gets the skb->hash from sk->sk_txhash,
> which is generated randomly. ip6_make_flowlabel then uses the hash to
> create a flowlabel. The reset packet doesn't get assigned a hash, so the
> flowlabel is calculated with flowi6.
> 
> The patches fix the issue.

Please resubmit this when the net-next tree opens back up as it is
closed right now, thank you.