Re: [PATCH] ipv6: Should use consistent conditional judgement for ip6 fragment between __ip6_append_data and ip6_finish_output

From: David Miller
Date: Thu Dec 29 2016 - 11:55:49 EST

From: Zheng Li <lizheng043@xxxxxxxxx>
Date: Wed, 28 Dec 2016 23:23:46 +0800

> From: Zheng Li <>
> There is an inconsistent conditional judgement between __ip6_append_data
> and ip6_finish_output functions, the variable length in __ip6_append_data
> just include the length of application's payload and udp6 header, don't
> include the length of ipv6 header, but in ip6_finish_output use
> (skb->len > ip6_skb_dst_mtu(skb)) as judgement, and skb->len include the
> length of ipv6 header.
> That causes some particular application's udp6 payloads whose length are
> between (MTU - IPv6 Header) and MTU were fragmented by ip6_fragment even
> though the rst->dev support UFO feature.
> Add the length of ipv6 header to length in __ip6_append_data to keep
> consistent conditional judgement as ip6_finish_output for ip6 fragment.
> Signed-off-by: Zheng Li <>

Applied, thank you.