Andy Gospodarek wrote:
> On 9/11/06, David Kimdon <david.kimdon at devicescape.com> wrote:
>> Hi,
>>
>> The attached patches enables the bridge to filter and forward packets
>> according to their IEEE 802.1q headers. The goals behind this change
>> include :
>>
>> - Enable running STP on 802.1q tagged networks. STP packets
>> must be untagged. It isn't obvious how else to enable STP
>> with the current bridge and vlan code.
>> - Add native support for an untagged vlan. Currently an untagged
>> vlan can be implimented using ebtables or similar.
>> - On devices bridging a large number of interfaces across various
>> vlans this significantly simplifies configuration and, depending on
>> configuration, can improve performance.
>>
>> Comments appreciated,
>>
>> David
>
>
> David,
>
> It looks like this code specifically ignores (which is OK for now) and
> clears (which is not OK) the frame's 802.1p priority. Have you tested
> priority-tagged frames to see if they are passed correctly? It seems
> like you should consider adding another field to the sk_buff structure
> so priority of the incoming frame can be tracked as well as add logic
> to br_vlan_output_frame and br_vlan_input_frame so the tag is saved.
> Something like this would probably be fine:
>
> Signed-off-by: Andy Gospodarek <andy at greyhouse.net>
>
> --- ./include/linux/skbuff.h.gospo 2006-09-11 14:41:54.000000000 -0400
> +++ ./include/linux/skbuff.h 2006-09-11 14:43:27.000000000 -0400
> @@ -297,6 +297,7 @@ struct sk_buff {
> __u32 nfmark;
> #endif /* CONFIG_NETFILTER */
> #ifdef CONFIG_BRIDGE_VLAN
> + unsigned int vlan_priority;
> unsigned int vlan;
> #endif
SKB bloat is not good for performance. You can store the priority and the VID in
a single 32-bit number with room to spare...
The skb->priority is also a possible place to store the VLAN priority.
The actual VLAN code has a mapping from vlan-priority -> skb priority on ingress,
and another mapping of skb->priority -> vlan-priority on egress. You probably
don't need to worry about this mapping for a bridge, however.
Ben
--
Ben Greear <greearb at candelatech.com>
Candela Technologies Inc http://www.candelatech.com
