On Tue, Jan 23, 2018 at 10:59:49AM +0100, Matthias Schiffer wrote:
eth_type_trans() internally calls skb_pull(), which does not adjust
skb checksum; skb_postpull_rcsum() is necessary to avoid log spam of the
form "bat0: hw csum failure" when packets with CHECKSUM_COMPLETE are
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 nor occur on every
system using batman-adv. I could reproduce this issue by stacking
batman-adv on top of a VXLAN interface.
Signed-off-by: Matthias Schiffer <mschiffer(a)universe-factory.net>
Seems reasonable, this change.
I'm just a little confused though: Two years ago someone had reported
checksumming errors with a Raspberry Pi and batman-adv:
And they seemed to be gone in newer kernel versions, while hardware
checksumming was supposedly still enabled.
Are the issues reproduceable without using VXLANs (for instance on
a Pi1 or Pi2)? Are they reproduceable on a recent kernel version?
(I guess you tested with a 4.4 kernel?)