Hi Phil,
On Tue, Oct 08, 2019 at 06:14:40PM +0200, Phil Sutter wrote:
> Replace the simple have_cache boolean by a cache level indicator
> defining how complete the cache is. Since have_cache indicated full
> cache (including rules), make code depending on it check for cache level
> NFT_CL_RULES.
>
> Core cache fetching routine __nft_build_cache() accepts a new level via
> parameter and raises cache completeness to that level.
>
> Signed-off-by: Phil Sutter <phil@xxxxxx>
> ---
> iptables/nft-cache.c | 51 +++++++++++++++++++++++++++++++-------------
> iptables/nft.h | 9 +++++++-
> 2 files changed, 44 insertions(+), 16 deletions(-)
>
> diff --git a/iptables/nft-cache.c b/iptables/nft-cache.c
> index 5444419a5cc3b..22a87e94efd76 100644
> --- a/iptables/nft-cache.c
> +++ b/iptables/nft-cache.c
> @@ -224,30 +224,49 @@ static int fetch_rule_cache(struct nft_handle *h)
> return 0;
> }
>
> -static void __nft_build_cache(struct nft_handle *h)
> +static void __nft_build_cache(struct nft_handle *h, enum nft_cache_level level)
> {
> uint32_t genid_start, genid_stop;
>
> + if (level <= h->cache_level)
> + return;
> retry:
> mnl_genid_get(h, &genid_start);
> - fetch_table_cache(h);
> - fetch_chain_cache(h);
> - fetch_rule_cache(h);
> - h->have_cache = true;
> - mnl_genid_get(h, &genid_stop);
>
> + switch (h->cache_level) {
> + case NFT_CL_NONE:
> + fetch_table_cache(h);
> + if (level == NFT_CL_TABLES)
> + break;
> + /* fall through */
> + case NFT_CL_TABLES:
If the existing level is TABLES and use wants chains, then you have to
invalidate the existing table cache, then fetch the tables and chains
to make sure cache is consistent. I mean, extending an existing cache
might lead to inconsistencies.
Am I missing anything?
> + fetch_chain_cache(h);
> + if (level == NFT_CL_CHAINS)
> + break;
> + /* fall through */
> + case NFT_CL_CHAINS:
> + fetch_rule_cache(h);
> + if (level == NFT_CL_RULES)
> + break;
> + /* fall through */
> + case NFT_CL_RULES:
> + break;
> + }
> +
> + mnl_genid_get(h, &genid_stop);
> if (genid_start != genid_stop) {
> flush_chain_cache(h, NULL);
> goto retry;
> }
>
> + h->cache_level = level;
> h->nft_genid = genid_start;
> }
