Am 19. Juni 2015 19:40:46 MESZ, schrieb Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>:
>On Fri, Jun 19, 2015 at 03:59:48PM +0200, Patrick McHardy wrote:
>> On 19.06, Pablo Neira Ayuso wrote:
>> > On Fri, Jun 19, 2015 at 03:44:44PM +0200, Patrick McHardy wrote:
>> > > On 19.06, Pablo Neira Ayuso wrote:
>> > > > On Fri, Jun 19, 2015 at 03:13:36PM +0200, Patrick McHardy
>wrote:
>> > > > > > static int do_add_setelems(struct netlink_ctx *ctx, const
>struct handle *h,
>> > > > > > - const struct expr *expr)
>> > > > > > + const struct location *loc, struct expr *expr)
>> > > > > > {
>> > > > > > - if (netlink_add_setelems(ctx, h, expr) < 0)
>> > > > > > + struct set *set;
>> > > > > > +
>> > > > > > + if (netlink_get_set(ctx, h, loc) < 0)
>> > > > >
>> > > > > I think we should get it from the internal list and not from
>the
>> > > > > kernel.
>> > > >
>> > > > There is no such internal list at this moment, we retrieve the
>list
>> > > > only for do_command_list(). Are you suggesting to add the code
>to
>> > > > retrieve it inconditionally initially?
>> > >
>> > > We do have the table->sets list. Yeah, but we don't add it to
>that
>> > > list in the creation part, I see. Actually we should be doing
>that,
>> > > since otherwise we also won't support creating a set and adding
>> > > new elements in seperate commands but a single transaction.
>> >
>> > Right.
>> >
>> > > > > We can't add intervals to existing sets so far anyways, and
>this
>> > > > > would allow it, but it wouldn't work.
>> > > >
>> > > > Not sure what you mean with this.
>> > >
>> > > Intervals need to know the entire set content to be created
>correctly.
>> > > We don't handle incremental updates with intervals correctly ATM.
>> >
>> > What's the problem?
>>
>> Consider a set with an interval 0-10. We add an interval 9-11. This
>> effectively means 0-10 needs to be transformed to 0-8 and we don't
>> do that.
>>
>> The root cause is that the kernel must not have overlapping
>intervals.
>> They need to be transformed before adding them. This is what segtree
>> does.
>
>OK, so that transformation would look like:
>
>1) Fetch the existing elements in the set via netlink.
>2) Handle merges with the elements that the user has passed through
> command line.
>3) Build the segtree.
>4) Push it into the kernel. We need to mark all existing elements for
> the deletion plus add the new elements, all that in one single
> transaction.
>
>Is this your idea? So it looks like we need a bit more userspace code.
>
>With the existing approach, the kernel rejects overlapping segments
>with -EEXIST, so if the user is careful to avoid them there should be
>no problem. It's more restrictive than what the logic above, but set
>declarations with intervals will work until that code lands in the
>tree.
Sorry, missed this part. Are you sure about that? I'm pretty sure we only reject exact duplicates. Otherwise I'd agree, that would be fine for now.
>
>Thanks.
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