Re: [PATCH nft] tests: shell: check that rule add with index works with echo

[Pablo Neira Ayuso <pablo@netfilter.org>]

On Wed, Sep 04, 2019 at 10:13:37AM +0200, Phil Sutter wrote:
> Pablo,
> 
> On Tue, Sep 03, 2019 at 07:27:13PM -0400, Eric Garver wrote:
> > If --echo is used the rule cache will not be populated. This causes
> > rules added using the "index" keyword to be simply appended to the
> > chain. The bug was introduced in commit 3ab02db5f836 ("cache: add
> > NFT_CACHE_UPDATE and NFT_CACHE_FLUSHED flags").
> > 
> > Signed-off-by: Eric Garver <eric@garver.life>
> > ---
> > I think the issue is in cache_evaluate(). It sets the flags to
> > NFT_CACHE_FULL and then bails early, but I'm not sure of the best way to
> > fix it. So I'll start by submitting a test case. :)
> 
> In 3ab02db5f836a ("cache: add NFT_CACHE_UPDATE and NFT_CACHE_FLUSHED
> flags"), you introduced NFT_CACHE_UPDATE to control whether
> rule_evaluate() should call rule_cache_update(), probably assuming the
> latter function merely changes cache depending on current command. In
> fact, this function also links rules if needed (see call to
> link_rules()).
> 
> The old code you replaced also did not always call rule_cache_update(),
> but that was merely for sanity: If cache doesn't contain rules, there is
> no point in updating it with added/replaced/removed rules. The implicit
> logic is if we saw a rule command with 'index' reference, cache would be
> completed up to rule level (because of the necessary index to handle
> translation).
> 
> I'm not sure why you introduced NFT_CACHE_UPDATE in the first place, but
> following my logic (and it seems to serve no other purpose) I would set
> that flag whenever NFT_CACHE_RULE_BIT gets set. So IMHO,
> NFT_CACHE_UPDATE is redundant.

Please, just go ahead simplify this in case you found a way to do it.

Thanks.