From af1905dbec44445d75851996819ac2203670bd0f Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Fri, 22 Oct 2010 04:12:19 +0000 Subject: [PATCH] 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: Ben Hutchings Signed-off-by: David S. Miller --- net/core/dev.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/net/core/dev.c b/net/core/dev.c index e8a8dc19365b..3c5fbfbb3181 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -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); } /** -- 2.34.1