Re: [PATCH net] openvswitch: Fix egress tunnel info.

[Thomas Graf <tgraf@suug.ch>]

On 10/07/15 at 10:09am, Jiri Benc wrote:
> The big difference to the other features is this cannot be detected
> until half way through the setup.
> 
> What I'm proposing instead is to introduce a way to clearly and
> unambiguously detect whether lwtunnels are supported or not. We'll need
> this anyway: kernel 4.3 won't really support IPv6 tunneling with ovs,
> yet there's currently no way to determine whether it's supported or not
> (and, unlike with lwtunnel detection, there's not even a hacky way).
> Querying the datapath for the supported features is needed
> nevertheless; it's only logical to use it for the lwtunnel vs. old
> vport decision, too.
> 
> I don't understand why you're opposed to this: it's much cleaner and
> there's no problem with lwtunnels not being used with the 4.3 kernel,
> everything should work just fine.

Extending ovs_dp_cmd_fill_info() to dump a new dp->kernel_features
via a new Netlink attribtue which signals these capabilities looks
like a straight forward way to solve this.

OVS just needs to set NLM_F_ECHO when creating the initial datapath.