| From | Kamal Mostafa <> | Subject | [PATCH 3.19.y-ckt 016/160] vlan: Fix untag operations of stacked vlans with REORDER_HEADER off | Date | Tue, 19 Jan 2016 17:04:54 -0800 |
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3.19.8-ckt13 -stable review patch. If anyone has any objections, please let me know.
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From: Vlad Yasevich <vyasevich@gmail.com>
[ Upstream commit a6e18ff111701b4ff6947605bfbe9594ec42a6e8 ]
When we have multiple stacked vlan devices all of which have turned off REORDER_HEADER flag, the untag operation does not locate the ethernet addresses correctly for nested vlans. The reason is that in case of REORDER_HEADER flag being off, the outer vlan headers are put back and the mac_len is adjusted to account for the presense of the header. Then, the subsequent untag operation, for the next level vlan, always use VLAN_ETH_HLEN to locate the begining of the ethernet header and that ends up being a multiple of 4 bytes short of the actuall beginning of the mac header (the multiple depending on the how many vlan encapsulations ethere are).
As a reslult, if there are multiple levles of vlan devices with REODER_HEADER being off, the recevied packets end up being dropped.
To solve this, we use skb->mac_len as the offset. The value is always set on receive path and starts out as a ETH_HLEN. The value is also updated when the vlan header manupations occur so we know it will be correct.
Signed-off-by: Vladislav Yasevich <vyasevic@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Kamal Mostafa <kamal@canonical.com> --- net/core/skbuff.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index ce3b085..060b5f7 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4216,7 +4216,8 @@ static struct sk_buff *skb_reorder_vlan_header(struct sk_buff *skb) return NULL; } - memmove(skb->data - ETH_HLEN, skb->data - VLAN_ETH_HLEN, 2 * ETH_ALEN); + memmove(skb->data - ETH_HLEN, skb->data - skb->mac_len, + 2 * ETH_ALEN); skb->mac_header += VLAN_HLEN; return skb; } -- 1.9.1
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