vlan: adjust vlan_set_encap_proto() for its callers
authorCong Wang <amwang@redhat.com>
Thu, 21 Feb 2013 23:32:27 +0000 (23:32 +0000)
committerDavid S. Miller <davem@davemloft.net>
Sun, 24 Feb 2013 02:00:06 +0000 (21:00 -0500)
commitda8c87241c26aac81a64c7e4d21d438a33018f4e
treeff2224eaeac133a20ce0ab7f128d386a8216c4b3
parent8e904550d0fffcda2b18d7ab12750b0c75757e89
vlan: adjust vlan_set_encap_proto() for its callers

There are two places to call vlan_set_encap_proto():
vlan_untag() and __pop_vlan_tci().

vlan_untag() assumes skb->data points after mac addr, otherwise
the following code

        vhdr = (struct vlan_hdr *) skb->data;
        vlan_tci = ntohs(vhdr->h_vlan_TCI);
        __vlan_hwaccel_put_tag(skb, vlan_tci);

        skb_pull_rcsum(skb, VLAN_HLEN);

won't be correct. But __pop_vlan_tci() assumes points _before_
mac addr.

In vlan_set_encap_proto(), it looks for some magic L2 value
after mac addr:

        rawp = skb->data;
        if (*(unsigned short *) rawp == 0xFFFF)
...

Therefore __pop_vlan_tci() is obviously wrong.

A quick fix is avoiding using skb->data in vlan_set_encap_proto(),
use 'vhdr+1' is always correct in both cases.

Cc: David S. Miller <davem@davemloft.net>
Cc: Jesse Gross <jesse@nicira.com>
Signed-off-by: Cong Wang <amwang@redhat.com>
Acked-by: Jesse Gross <jesse@nicira.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
include/linux/if_vlan.h