From: we...@ucloud.cn
Date: Tue, 9 Aug 2016 15:04:21 +0800
> From: wenxu <we...@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 <we...@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?
