Re: [PATCH net-next RFC v2 1/3] lwt: infrastructure to support light weight tunnels

[roopa <roopa@cumulusnetworks.com>]

On 6/21/15, 1:40 PM, Thomas Graf wrote:
> On 06/20/15 at 07:27am, roopa wrote:
>> On 6/19/15, 11:39 AM, Robert Shearman wrote:
>>>
>>> Sorry for not being clear, but I meant that there would have to be
>>> lwtunnel_skb_lwstate functions for ipv4 and ipv6 to match the output
>>> functions. So in the vxlan use case where it's using a netdevice, how
>>> would it determine which one to call?
>> thanks for that clarification, and good point. I see some areas of the
>> kernel checking for skb->protocol to do the conversion (something like
>> below). I am guessing that is acceptable.
>> if (skb->protocol == htons(ETH_P_IPV6))
>>                  struct rt6_info *rt6 = (struct rt6_info *)skb_dst(skb);
> I'm not yet convinced that it makes sense to offer the no-netdevice
> shortcut for VXLAN. I'm not convinced we need yet another VXLAN data
> path. In fact, I'm trying to get rid of the OVS one for this specific
> reason.
>
> I have no objection though if somebody comes up with an architecture
> that can't just pass the required metadata between the namespaces and
> do the actual encapsulation in a single net_device in the root/host
> namespace.
>
> Either way, I thin it's fair to defer to this to a later point. We
> don't need to solve this for the first iteration of MPLS and VXLAN
> implementation.
ack, thanks for your thoughts on this.