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Commit af1905db authored by Ben Hutchings's avatar Ben Hutchings Committed by David S. Miller
Browse files

net: Fix some corner cases in dev_can_checksum() 



dev_can_checksum() incorrectly returns true in these cases:

1. The skb has both out-of-band and in-band VLAN tags and the device
   supports checksum offload for the encapsulated protocol but only with
   one layer of encapsulation.
2. The skb has a VLAN tag and the device supports generic checksumming
   but not in conjunction with VLAN encapsulation.

Rearrange the VLAN tag checks to avoid these.

Signed-off-by: default avatarBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent cd0ea241

net/core/dev.c

+6 −10
Original line number Diff line number Diff line
@@ -1696,22 +1696,18 @@ static bool can_checksum_protocol(unsigned long features, __be16 protocol) 


static bool dev_can_checksum(struct net_device *dev, struct sk_buff *skb)

{

	__be16 protocol = skb->protocol;

	int features = dev->features;



	if (vlan_tx_tag_present(skb))

	if (vlan_tx_tag_present(skb)) {

		features &= dev->vlan_features;



	if (can_checksum_protocol(features, skb->protocol))

		return true;



	if (skb->protocol == htons(ETH_P_8021Q)) {

	} else if (protocol == htons(ETH_P_8021Q)) {

		struct vlan_ethhdr *veh = (struct vlan_ethhdr *)skb->data;

		if (can_checksum_protocol(dev->features & dev->vlan_features,

					  veh->h_vlan_encapsulated_proto))

			return true;

		protocol = veh->h_vlan_encapsulated_proto;

		features &= dev->vlan_features;

	}



	return false;

	return can_checksum_protocol(features, protocol);

}



/**