[LEDE-DEV] [PATCH netifd 1/2] interface-ip: set address indicator flag when IPv6 address lifetime changes

[Hans Dedecker]

On Fri, Mar 10, 2017 at 12:08 AM, Matthias Schiffer
<mschiffer at universe-factory.net> wrote:
> On 03/09/2017 11:03 PM, Hans Dedecker wrote:
>> On Thu, Mar 9, 2017 at 10:20 PM, Matthias Schiffer
>> <mschiffer at universe-factory.net> wrote:
>>> On 03/09/2017 05:32 PM, Hans Dedecker wrote:
>>>> Trigger interface update event when IPv6 address lifetime changes by setting
>>>> the address indicator flag to inform external subsystems about IPv6 address
>>>> lifetime change.
>>>>
>>>> Signed-off-by: Hans Dedecker <dedeckeh at gmail.com>
>>>
>>> AFAICT, this will cause a lot of ifupdate events in big IPv6 networks (for
>>> example, some large mesh networks based on Gluon have more than 4000 client
>>> and 5-10 radvds, often causing more than one RA per second, each updating
>>> valid/preferred lifetimes). We *really* want to avoid causing lots of
>>> reloads for services that set triggers on interface updates; the majority
>>> of services is not interested in the lifetimes of addresses at all.
>> The netifd patch set is a result of a reported hnet issue
>> (https://github.com/openwrt/openwrt/issues/346).
>> The problem is triggered by netifd commit
>> https://git.lede-project.org/?p=project/netifd.git;a=commit;h=b8ef742bd04ebef324ae11aee56c6e1d2cb7e0ad;
>> before this commit an interface update event was always triggered
>> independant from the interface updated flag and thus indeed causing
>> lots of service reloads that set triggers on interface updates. Now it
>> seems by restricting the interface update events hnet package is
>> broken as the lifetime of the IPv6 addresses is not refreshed anymore.
>> After doing code review in hnet package I noticed it relies on
>> interface update notifications; hnet certainly picks up the delegated
>> prefix via interface update notifications I'm not 100% sure about IPv6
>> addresses as I'm not a hnet package expert nor do I have a setup on
>> which I can test it. I'm fine leaving this patch out but leaving the
>> other netifd patch
>> (http://lists.infradead.org/pipermail/lede-dev/2017-March/006605.html)
>> out will certainly keep the hnet package broken.
>>
>> Hans
>>>
>
> Hmm, what exactly are these prefix objects in netifd? Is this only used for
> prefix delegation via DHCPv6? If it is, the second patch should not trigger
> updates for each RA, right? If that's the case, I don't see an issue with it.
It's indeed used for prefix delegation via DHCPv6 thus it should not
trigger an interface update for each RA

Hans
>
> Matthias
>