linux-kernel - Re: [PATCH v2] ipv4: Should use consistent conditional judgement for ip fragment in __ip_append_data and ip_finish

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Date:   Tue, 20 Dec 2016 10:45:46 -0500 (EST)
From:   David Miller <davem@...emloft.net>
To:     lizheng043@...il.com
Cc:     linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
        kuznet@....inr.ac.ru, jmorris@...ei.org, yoshfuji@...ux-ipv6.org,
        kaber@...sh.net, james.z.li@...csson.com
Subject: Re: [PATCH v2] ipv4: Should use consistent conditional judgement
 for ip fragment in __ip_append_data and ip_finish_output

From: Zheng Li <lizheng043@...il.com>
Date: Mon, 12 Dec 2016 09:56:05 +0800

> From: zheng li <james.z.li@...csson.com>
> 
> There is an inconsistent conditional judgement in __ip_append_data and
> ip_finish_output functions, the variable length in __ip_append_data just
> include the length of application's payload and udp header, don't include
> the length of ip header, but in ip_finish_output use
> (skb->len > ip_skb_dst_mtu(skb)) as judgement, and skb->len include the
> length of ip header.
> 
> That causes some particular application's udp payload whose length is
> between (MTU - IP Header) and MTU were fragmented by ip_fragment even
> though the rst->dev support UFO feature.
> 
> Add the length of ip header to length in __ip_append_data to keep
> consistent conditional judgement as ip_finish_output for ip fragment.
> 
> Signed-off-by: Zheng Li <james.z.li@...csson.com>

Applied, thanks.