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Commit b6aa03f1 authored by Matthias Schiffer's avatar Matthias Schiffer Committed by Greg Kroah-Hartman
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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: c6c8fea2 ("net: Add batman-adv meshing protocol")
Tested-by: default avatarMaximilian Wilhelm <max@sdn.clinic>
Signed-off-by: default avatarMatthias Schiffer <mschiffer@universe-factory.net>
Signed-off-by: default avatarSven Eckelmann <sven@narfation.org>
Signed-off-by: default avatarSimon Wunderlich <sw@simonwunderlich.de>
Signed-off-by: default avatarSasha Levin <alexander.levin@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent b6e82d77

net/batman-adv/soft-interface.c

+1 −7
Original line number Diff line number Diff line
@@ -448,13 +448,7 @@ 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,