From: Vlad Yasevich Date: Mon, 16 Nov 2015 20:43:44 +0000 (-0500) Subject: vlan: Fix untag operations of stacked vlans with REORDER_HEADER off X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=a6e18ff1117;p=sagit-ice-cold%2Fkernel_xiaomi_msm8998.git 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 Signed-off-by: David S. Miller --- 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; }