diff options
| author | Cong Wang <amwang@redhat.com> | 2013-02-22 17:32:26 +0800 |
|---|---|---|
| committer | Jesse Gross <jesse@nicira.com> | 2013-02-22 17:02:38 -0800 |
| commit | 7b024082b2b279af58e24ebd46e81777723d58da (patch) | |
| tree | bea9b80e2869695f4da100df6c0b3731bd02fe1e /net/openvswitch | |
| parent | 17b682a04841233f827073b327c6533e478dfcd4 (diff) | |
openvswitch: fix the calculation of checksum for vlan header
In vlan_insert_tag(), we insert a 4-byte VLAN header _after_
mac header:
memmove(skb->data, skb->data + VLAN_HLEN, 2 * ETH_ALEN);
...
veth->h_vlan_proto = htons(ETH_P_8021Q);
...
veth->h_vlan_TCI = htons(vlan_tci);
so after it, we should recompute the checksum to include these 4 bytes.
skb->data still points to the mac header, therefore VLAN header is at
(2 * ETH_ALEN = 12) bytes after it, not (ETH_HLEN = 14) bytes.
This can also be observed via tcpdump:
0x0000: ffff ffff ffff 5254 005d 6f6e 8100 000a
0x0010: 0806 0001 0800 0604 0001 5254 005d 6f6e
0x0020: c0a8 026e 0000 0000 0000 c0a8 0282
Similar for __pop_vlan_tci(), the vlan header we remove is the one
overwritten in:
memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
Therefore the VLAN_HLEN = 4 bytes after 2 * ETH_ALEN is the part
we want to sub from checksum.
Cc: David S. Miller <davem@davemloft.net>
Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Signed-off-by: Jesse Gross <jesse@nicira.com>
Diffstat (limited to 'net/openvswitch')
| -rw-r--r-- | net/openvswitch/actions.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/net/openvswitch/actions.c b/net/openvswitch/actions.c index ac2defeeba83..d4d5363c7ba7 100644 --- a/net/openvswitch/actions.c +++ b/net/openvswitch/actions.c @@ -58,7 +58,7 @@ static int __pop_vlan_tci(struct sk_buff *skb, __be16 *current_tci) if (skb->ip_summed == CHECKSUM_COMPLETE) skb->csum = csum_sub(skb->csum, csum_partial(skb->data - + ETH_HLEN, VLAN_HLEN, 0)); + + (2 * ETH_ALEN), VLAN_HLEN, 0)); vhdr = (struct vlan_hdr *)(skb->data + ETH_HLEN); *current_tci = vhdr->h_vlan_TCI; @@ -115,7 +115,7 @@ static int push_vlan(struct sk_buff *skb, const struct ovs_action_push_vlan *vla if (skb->ip_summed == CHECKSUM_COMPLETE) skb->csum = csum_add(skb->csum, csum_partial(skb->data - + ETH_HLEN, VLAN_HLEN, 0)); + + (2 * ETH_ALEN), VLAN_HLEN, 0)); } __vlan_hwaccel_put_tag(skb, ntohs(vlan->vlan_tci) & ~VLAN_TAG_PRESENT); |