On 11 July 2017 at 20:11, Phil Sutter <phil@xxxxxx> wrote:
> Hi,
>
> On Thu, Jul 06, 2017 at 04:36:45PM +0200, Arturo Borrero Gonzalez wrote:
>> If you add set elements to interval sets, the output is wrong.
>> Fix this by caching first element of the range (first event),
>> then wait for the second element of the range (second event) to
>> print them both at the same time.
>
> As promised, I am preparing my own solution for side-by-side comparison.
> Though I'm running into problems and want to use the occasion to discuss
> them first:
>
> What I wasn't able to solve yet are half-open ranges, like so:
>
> | nft add set ip t portrange { type inet_service; flags interval; }
> | nft add element ip t portrange { 1024-65535 }
>
> In this case there is only a single element with value 1024 which
> doesn't have EXPR_F_INTERVAL_END set. Looking at
> interval_map_decompose(), this is identified to be a range till the end
> of the scope if it's the last element in the set.
>
> In monitor code though, I can't predict whether an interval end element
> will come afterwards or not, so I end up caching the element and
> everything turns into a mess. I'm pretty sure your solution has the same
> problem, could you check that?
>
> Right now, I only see two ways to get this sorted:
>
> 1) Change kernel code to always include both start end end of a range in
> a single notification. This would eliminate the need for any caching
> in netlink_events_setelem_cb() altogether!
>
> 2) Change monitor code to cache all events until the final NFTA_GEN_ID
> message, then handle all messages at once.
>
> What do you think?
>
We should avoid touching the kernel for this.
Anyway, my patch doesn't solve the same issue for deleting range elements.
In this patch I added the logic in netlink_events_setelem_cb() and
probably a better place for this
is in the netlink_events_cache_update() routine.
I'm sending a patch to add a bit of debugging to the monitor code path
meanwhile we solve this issue.
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