On Tue, 13 Dec 2016 01:12:38 +0100 (CET), Michał Mirosław wrote:
> @@ -850,20 +848,11 @@ static int validate_vlan_from_nlattrs(const struct
> sw_flow_match *match,
> return -EINVAL;
> }
>
> - if (a[OVS_KEY_ATTR_VLAN])
> - tci = nla_get_be16(a[OVS_KEY_ATTR_VLAN]);
> -
> - if (!(tci & htons(VLAN_TAG_PRESENT))) {
> - if (tci) {
> - OVS_NLERR(log, "%s TCI does not have VLAN_TAG_PRESENT
> bit set.",
> - (inner) ? "C-VLAN" : "VLAN");
> - return -EINVAL;
> - } else if (nla_len(a[OVS_KEY_ATTR_ENCAP])) {
> - /* Corner case for truncated VLAN header. */
> - OVS_NLERR(log, "Truncated %s header has non-zero encap
> attribute.",
> - (inner) ? "C-VLAN" : "VLAN");
> - return -EINVAL;
> - }
> + if (!a[OVS_KEY_ATTR_VLAN] && nla_len(a[OVS_KEY_ATTR_ENCAP])) {
> + /* Corner case for truncated VLAN header. */
> + OVS_NLERR(log, "Truncated %s header has non-zero encap
> attribute.",
> + (inner) ? "C-VLAN" : "VLAN");
> + return -EINVAL;
This looks wrong. The zero value of nla_get_be16(a[OVS_KEY_ATTR_VLAN])
together with empty a[OVS_KEY_ATTR_ENCAP] means truncated VLAN header
and this needs to be preserved.
In other words, you need to check also !nla_get_be16(a[OVS_KEY_ATTR_VLAN])
here.
Overall, this whole patch looks very suspicious from the very
beginning. The xors used are strong indication that something is not
right.
And indeed, you're breaking uAPI compatibility. Previously, the
VLAG_TAG_PRESENT bit set in OVS_KEY_ATTR_VLAN caused the flow to match
on packets with VLAN tag present. After this patch, it causes the flow
to match only on those packets that have a certain value of
VLAN_CFI_MASK in their VLAN tag (I haven't bother deciphering what
value is checked after all these xors, it's as well possible that it
will also match on packets _without_ any VLAN header).
You have to preserve the old meaning of VLAN_TAG_PRESENT in
OVS_KEY_ATTR_VLAN. When doing flow lookups, VLAN_TAG_PRESENT must match
on and only on packets that have VLAN tag present, irrespective of their
VLAN_CFI_MASK.
If you want to introduce support for lookups on VLAN_CFI_MASK, you'll
have to do that by introducing a new netlink attribute.
Jiri
