batman-adv: fix packet checksum in receive path
authorMatthias Schiffer <mschiffer@universe-factory.net>
Tue, 23 Jan 2018 09:59:49 +0000 (10:59 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 30 May 2018 05:50:31 +0000 (07:50 +0200)
commitb6aa03f189cde8996534ca55e8b8e15c719359ed
tree0407f8bb94d1b7224767a54ea1a08e1b4cb94c04
parentb6e82d779221034848dd73e0663f3288baf2003a
batman-adv: fix packet checksum in receive path

[ Upstream commit abd6360591d3f8259f41c34e31ac4826dfe621b8 ]

eth_type_trans() internally calls skb_pull(), which does not adjust the
skb checksum; skb_postpull_rcsum() is necessary to avoid log spam of the
form "bat0: hw csum failure" when packets with CHECKSUM_COMPLETE are
received.

Note that in usual setups, packets don't reach batman-adv with
CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see
batadv's ethtype?), which is why the log messages do not occur on every
system using batman-adv. I could reproduce this issue by stacking
batman-adv on top of a VXLAN interface.

Fixes: c6c8fea29769 ("net: Add batman-adv meshing protocol")
Tested-by: Maximilian Wilhelm <max@sdn.clinic>
Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/batman-adv/soft-interface.c