Re: [PATCH net] ip6_tunnel: fix GRE6 segmentation
From: Vadim Fedorenko <hidden>
Date: 2021-06-22 01:58:26
On 22.06.2021 02:52, Jakub Kicinski wrote:
Commit 6c11fbf97e69 ("ip6_tunnel: add MPLS transmit support")
moved assiging inner_ipproto down from ipxip6_tnl_xmit() to
its callee ip6_tnl_xmit(). The latter is also used by GRE.
Since commit 38720352412a ("gre: Use inner_proto to obtain inner
header protocol") GRE had been depending on skb->inner_protocol
during segmentation. It sets it in gre_build_header() and reads
it in gre_gso_segment(). Changes to ip6_tnl_xmit() overwrite
the protocol, resulting in GSO skbs getting dropped.
Note that inner_protocol is a union with inner_ipproto,
GRE uses the former while the change switched it to the latter
(always setting it to just IPPROTO_GRE).
Restore the original location of skb_set_inner_ipproto(),
it is unclear why it was moved in the first place.
Fixes: 6c11fbf97e69 ("ip6_tunnel: add MPLS transmit support")
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
---Tested-by: Vadim Fedorenko <redacted>