From: Matthias Schiffer Date: Tue, 23 Jan 2018 10:59:49 +0100 Subject: batman-adv: fix packet checksum in receive path 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: fe28a94c01e1 ("batman-adv: receive packets directly using skbs") Signed-off-by: Matthias Schiffer Signed-off-by: Sven Eckelmann Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/798174b15153afd88268f2f87811602f68b3f2c6 diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c index 08432b14386a53c771c54b9eb38893d94c6f9b53..5da1a1c0f1efb5d95f31bc852b899f61e462feb1 100644 --- a/net/batman-adv/soft-interface.c +++ b/net/batman-adv/soft-interface.c @@ -470,13 +470,7 @@ 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,