3.16.7-ckt22 -stable review patch. If anyone has any objections, please let me
know.
------------------
From: Vlad Yasevich <vyasev...@gmail.com>
commit a6e18ff111701b4ff6947605bfbe9594ec42a6e8 upstream.
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 <vyase...@redhat.com>
Signed-off-by: David S. Miller <da...@davemloft.net>
Signed-off-by: Luis Henriques <luis.henriq...@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 a280d04a3414..d50deee76502 100644
--- a/net/core/skbuff.c
+++ b/net/core/skbuff.c
@@ -3996,7 +3996,8 @@ 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;
}
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