batman-adv/patches/0024-batman-adv-fix-packet-checksum-in-receive-path.patch

   1 From: Matthias Schiffer <mschiffer@universe-factory.net>
   2 Date: Tue, 23 Jan 2018 10:59:49 +0100
   3 Subject: batman-adv: fix packet checksum in receive path
   4
   5 eth_type_trans() internally calls skb_pull(), which does not adjust the
   6 skb checksum; skb_postpull_rcsum() is necessary to avoid log spam of the
   7 form "bat0: hw csum failure" when packets with CHECKSUM_COMPLETE are
   8 received.
   9
  10 Note that in usual setups, packets don't reach batman-adv with
  11 CHECKSUM_COMPLETE (I assume NICs bail out of checksumming when they see
  12 batadv's ethtype?), which is why the log messages do not occur on every
  13 system using batman-adv. I could reproduce this issue by stacking
  14 batman-adv on top of a VXLAN interface.
  15
  16 Fixes: fe28a94c01e1 ("batman-adv: receive packets directly using skbs")
  17 Signed-off-by: Matthias Schiffer <mschiffer@universe-factory.net>
  18 Signed-off-by: Sven Eckelmann <sven@narfation.org>
  19
  20 Origin: upstream, https://git.open-mesh.org/batman-adv.git/commit/798174b15153afd88268f2f87811602f68b3f2c6
  21
  22 diff --git a/net/batman-adv/soft-interface.c b/net/batman-adv/soft-interface.c
  23 index 08432b14386a53c771c54b9eb38893d94c6f9b53..5da1a1c0f1efb5d95f31bc852b899f61e462feb1 100644
  24 --- a/net/batman-adv/soft-interface.c
  25 +++ b/net/batman-adv/soft-interface.c
  26 @@ -470,13 +470,7 @@ void batadv_interface_rx(struct net_device *soft_iface,
  27
  28         /* skb->dev & skb->pkt_type are set here */
  29         skb->protocol = eth_type_trans(skb, soft_iface);
  30 -
  31 -       /* should not be necessary anymore as we use skb_pull_rcsum()
  32 -        * TODO: please verify this and remove this TODO
  33 -        * -- Dec 21st 2009, Simon Wunderlich
  34 -        */
  35 -
  36 -       /* skb->ip_summed = CHECKSUM_UNNECESSARY; */
  37 +       skb_postpull_rcsum(skb, eth_hdr(skb), ETH_HLEN);
  38
  39         batadv_inc_counter(bat_priv, BATADV_CNT_RX);
  40         batadv_add_counter(bat_priv, BATADV_CNT_RX_BYTES,