| Message ID | 05cee97344804ffb2a8df87603663a098fd0cb36.1516701590.git.mschiffer@universe-factory.net |
|---|---|
| State | Accepted, archived |
| Delegated to: | Simon Wunderlich |
| Headers | show |
| Series | [maint,v2,1/2] batman-adv: fix packet checksum in receive path | expand |
On Tue, Jan 23, 2018 at 10:59:49AM +0100, Matthias Schiffer wrote: > 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 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@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: https://www.open-mesh.org/issues/224 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?) Regards, Linus
On Dienstag, 23. Januar 2018 10:59:49 CET Matthias Schiffer wrote: > 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 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@universe-factory.net> > --- Applied both as 798174b15153 [1] and 2c1bce065baa [2]. They are also queued up in linux-merge [3] but will most likely only forwarded when Simon is back from his vacation. Tested-by's are still welcome :) Thanks, Sven [1] https://git.open-mesh.org/batman-adv.git/commit/798174b15153afd88268f2f87811602f68b3f2c6 [2] https://git.open-mesh.org/batman-adv.git/commit/2c1bce065baa688bc1eca4116f83ca3b790432a5 [3] https://git.open-mesh.org/linux-merge.git/shortlog/refs/heads/batadv/net
diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 9f673cdf..6f7ce7a6 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -451,13 +451,7 @@ void batadv_interface_rx(struct net_device *soft_iface, /* skb->dev & skb->pkt_type are set here */ skb->protocol = eth_type_trans(skb, soft_iface); - - /* should not be necessary anymore as we use skb_pull_rcsum() - * TODO: please verify this and remove this TODO - * -- Dec 21st 2009, Simon Wunderlich - */ - - /* skb->ip_summed = CHECKSUM_UNNECESSARY; */ + skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN); batadv_inc_counter(bat_priv, BATADV_CNT_RX); batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,
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 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@universe-factory.net> --- net/batman-adv/soft-interface.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-)