[LEDE-DEV] [OpenWrt-Devel] [PATCH netifd 2/3] interface: Only teardown interfaces having no proto task when l3_dev link lost

[Felix Fietkau]

On 2016-07-14 13:28, Hans Dedecker wrote:
> On Thu, Jul 14, 2016 at 12:01 PM, Yousong Zhou <yszhou4tech at gmail.com> wrote:
>> On 14 July 2016 at 16:14, Hans Dedecker <dedeckeh at gmail.com> wrote:
>>> Commit c6858766 adds teardown support when l3_dev link is lost especially for shell protocols
>>> that have no proto task. However shell protocols which have a proto task running like ppp will
>>> also be teared down which is not always the expected action.
>>> As an example the PPP daemon can be put into persist state trying to re-establish the link via
>>> a hold off mechanism which is not possible when the daemon is terminated by the proto shell
>>> teardown.
>>> Therefore restrict the teardown action for shell protocols having no proto task.
>>>
>>
>> How about adding an extra flag like managed-link, persistent-link,
>> on-demand-link?  It looks to me doing teardown at link-down is more
>> common a case.
> Initially I was thinking about adding another flag like you propose
> but then I was doubting if the change in behavior for shell protocols
> having a proto task task was on purpose or not. In case of PPP and
> link failure you don't want an immediate restart by netifd in some
> cases (see https://github.com/lede-project/source/pull/200) as PPP
> daemon can take care of the link re-negotiation based on a holdoff
> timeout.
> Additionally if the wan link loses connectivity a link down
> notification will be received on the main device which will teardown
> the protocol. Anyway I'm open for suggestions which way to go forward.
Yousong,

please provide some more details on where your commit c6858766 is
actually needed/useful. In all the use cases I can think of, handling
setup/teardown based on the l2 dev should be enough.

- Felix