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| author | Vlad Yasevich <vyasevich@gmail.com> | 2015-11-16 21:43:44 +0100 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-11-17 20:38:35 +0100 |
| commit | a6e18ff111701b4ff6947605bfbe9594ec42a6e8 (patch) | |
| tree | b6905bc0ea1eadc2a237dcefe3d88f14fd1e00e0 /net | |
| parent | via-velocity: unconditionally drop frames with bad l2 length (diff) | |
| download | linux-a6e18ff111701b4ff6947605bfbe9594ec42a6e8.tar.xz linux-a6e18ff111701b4ff6947605bfbe9594ec42a6e8.zip | |
vlan: Fix untag operations of stacked vlans with REORDER_HEADER off
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>
Diffstat (limited to 'net')
| -rw-r--r-- | net/core/skbuff.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/net/core/skbuff.c b/net/core/skbuff.c index aa41e6dd6429..152b9c70e252 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -4268,7 +4268,8 @@ 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; } |