[BRIDGE] netfilter: vlan + hw checksum = bug?

It looks like the bridge netfilter code does not correctly update
the hardware checksum after popping off the VLAN header.

This is by inspection, I have *not* tested this.
To test you would need to set up a filtering bridge with vlans
and a device the does hardware receive checksum (skge, or sungem)

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 4 deletions

diff --git a/net/bridge/br_netfilter.c b/net/bridge/br_netfilter.c
index 223f8270daee..7cac3fb9f809 100644
--- a/net/bridge/br_netfilter.c
+++ b/net/bridge/br_netfilter.c
@@ -394,8 +394,9 @@ inhdr_error:
  * target in particular.  Save the original destination IP
  * address to be able to detect DNAT afterwards. */
 static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
-   const struct net_device *in, const struct net_device *out,
-   int (*okfn)(struct sk_buff *))
+                                      const struct net_device *in,
+                                      const struct net_device *out,
+                                      int (*okfn)(struct sk_buff *))
 {
         struct iphdr *iph;
         __u32 len;
@@ -412,8 +413,10 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
                         goto out;
 
                 if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+                        u8 *vhdr = skb->data;
                         skb_pull(skb, VLAN_HLEN);
-                        (skb)->nh.raw += VLAN_HLEN;
+                        skb_postpull_rcsum(skb, vhdr, VLAN_HLEN);
+                        skb->nh.raw += VLAN_HLEN;
                 }
                 return br_nf_pre_routing_ipv6(hook, skb, in, out, okfn);
         }
@@ -429,8 +432,10 @@ static unsigned int br_nf_pre_routing(unsigned int hook, struct sk_buff **pskb,
                 goto out;
 
         if (skb->protocol == __constant_htons(ETH_P_8021Q)) {
+                u8 *vhdr = skb->data;
                 skb_pull(skb, VLAN_HLEN);
-                (skb)->nh.raw += VLAN_HLEN;
+                skb_postpull_rcsum(skb, vhdr, VLAN_HLEN);
+                skb->nh.raw += VLAN_HLEN;
         }
 
         if (!pskb_may_pull(skb, sizeof(struct iphdr)))