On Thu, Mar 30, 2017 at 6:22 AM, Jiri Benc <jb...@redhat.com> wrote:
> On Wed, 29 Mar 2017 17:14:10 -0700, Yi-Hung Wei wrote:
>> ovs_flow_key_update() is called when the flow key is invalid, and it is
>> used to update and revalidate the flow key. Commit 329f45bc4f19
>> ("openvswitch: add mac_proto field to the flow key") introduces mac_proto
>> field to flow key and use it to determine whether the flow key is valid.
>> However, the commit does not update the code path in ovs_flow_key_update()
>> to revalidate the flow key which may cause BUG_ON() on execute_recirc().
>> This patch addresses the aforementioned issue.
>
> Good catch.
>
>> int ovs_flow_key_update(struct sk_buff *skb, struct sw_flow_key *key)
>> {
>> + int res;
>> +
>> + res = key_extract_mac_proto(skb);
>> + if (res < 0)
>> + return res;
>> + key->mac_proto = res;
>> +
>> return key_extract(skb, key);
>> }
>
> But this should just reset the SW_FLOW_KEY_INVALID flag, there's no
> need to recompute mac_proto.
>
> Something like this:
>
> int ovs_flow_key_update(struct sk_buff *skb, struct sw_flow_key *key)
> {
> - return key_extract(skb, key);
> + int res;
> +
> + res = key_extract(skb, key);
> + if (!res)
> + key->mac_proto &= ~SW_FLOW_KEY_INVALID;
> + return res;
> }
Hi Jiri,
One case that I worry is that key_extract() currently relies on mac_proto to
decide whether to process the link layer. So if we update key->mac_proto
after key_extract(), wouldn't we run into a problem like the following?
If we invalidate a flow key of a L3 packet, the flow's mac_proto is like this
(MAC_PROTO_NONE | SW_FLOW_KEY_INVALID), then key_extract() will
process the link layer of this L3 packet since mac_proto !=MAC_PROTO_NONE?
In this case, shall we update key_extract() like this
static int key_extract(struct sk_buff *skb, struct sw_flow_key *key)
/* Link layer. */
clear_vlan(key);
- if (key->mac_proto == MAC_PROTO_NONE) {
+ if (key->mac_proto & MAC_PROTO_NONE) {
if (unlikely(eth_type_vlan(skb->protocol)))
return -EINVAL;
Thanks,
-Yi-Hung
>
> Thanks,
>
> Jiri
