From: David Miller <davem@davemloft.net>
To: wenxu@ucloud.cn
Cc: kuznet@ms2.inr.ac.ru, jmorris@namei.org, kaber@trash.net,
yoshfuji@linux-ipv6.org, netdev@vger.kernel.org,
shmulik.ladkani@gmail.com, wenx05124561@163.com,
hannes@stressinduktion.org
Subject: Re: [PATCH] net: ip_finish_output_gso: If skb_gso_network_seglen exceeds MTU, allow segmentation for gre tunneled skbs
Date: Wed, 10 Aug 2016 17:35:11 -0700 (PDT) [thread overview]
Message-ID: <20160810.173511.968926810628735179.davem@davemloft.net> (raw)
In-Reply-To: <1470726261-16371-1-git-send-email-wenxu@ucloud.cn>
From: wenxu@ucloud.cn
Date: Tue, 9 Aug 2016 15:04:21 +0800
> From: wenxu <wenxu@ucloud.cn>
>
> commit b8247f095edd ("net: ip_finish_output_gso: If skb_gso_network_seglen
> exceeds MTU, allow segmentation for local udp tunneled skbs")
>
> Given:
> - tap0 and ovs-gre
> - ovs-gre stacked on eth0, eth0 having the small mtu
>
> After encapsulation these skbs have skb_gso_network_seglen that exceed
> eth0's ip_skb_dst_mtu. So the finnal each segment would be larger than
> eth0 mtu. These packets maybe dropped.
>
> It has the same problem if tap0 bridge with ipgre or gretap device. So
> the IPSKB_FRAG_SEGS flags should also be set in gre tunneled skbs.
>
> Signed-off-by: wenxu <wenxu@ucloud.cn>
I am rather certain that this test is intentionally restricted to
UDP tunnel endpoints, because GRE and other tunnel types are PMTU safe.
Hannes and Shmulik?
next prev parent reply other threads:[~2016-08-11 0:35 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-09 7:04 [PATCH] net: ip_finish_output_gso: If skb_gso_network_seglen exceeds MTU, allow segmentation for gre tunneled skbs wenxu
2016-08-11 0:35 ` David Miller [this message]
2016-08-11 19:41 ` Shmulik Ladkani
2016-08-12 4:29 ` wenxu
[not found] ` <80d116d7-e61c-1bbd-64bf-e3b1f809419b@ucloud.cn>
2016-08-12 5:18 ` Shmulik Ladkani
2016-08-12 11:11 ` Hannes Frederic Sowa
2016-08-15 11:16 ` Shmulik Ladkani
2016-08-16 7:12 ` wenxu
2016-08-19 7:26 ` Shmulik Ladkani
2016-08-19 9:20 ` Hannes Frederic Sowa
2016-08-19 13:40 ` Shmulik Ladkani
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