diff options
Diffstat (limited to 'net/netfilter/nft_lookup.c')
| -rw-r--r-- | net/netfilter/nft_lookup.c | 46 |
1 files changed, 41 insertions, 5 deletions
diff --git a/net/netfilter/nft_lookup.c b/net/netfilter/nft_lookup.c index 40c602ffbcba..58c5b14889c4 100644 --- a/net/netfilter/nft_lookup.c +++ b/net/netfilter/nft_lookup.c @@ -24,11 +24,11 @@ struct nft_lookup { struct nft_set_binding binding; }; -#ifdef CONFIG_MITIGATION_RETPOLINE -const struct nft_set_ext * -nft_set_do_lookup(const struct net *net, const struct nft_set *set, - const u32 *key) +static const struct nft_set_ext * +__nft_set_do_lookup(const struct net *net, const struct nft_set *set, + const u32 *key) { +#ifdef CONFIG_MITIGATION_RETPOLINE if (set->ops == &nft_set_hash_fast_type.ops) return nft_hash_lookup_fast(net, set, key); if (set->ops == &nft_set_hash_type.ops) @@ -51,10 +51,46 @@ nft_set_do_lookup(const struct net *net, const struct nft_set *set, return nft_rbtree_lookup(net, set, key); WARN_ON_ONCE(1); +#endif return set->ops->lookup(net, set, key); } + +static unsigned int nft_base_seq(const struct net *net) +{ + /* pairs with smp_store_release() in nf_tables_commit() */ + return smp_load_acquire(&net->nft.base_seq); +} + +static bool nft_lookup_should_retry(const struct net *net, unsigned int seq) +{ + return unlikely(seq != nft_base_seq(net)); +} + +const struct nft_set_ext * +nft_set_do_lookup(const struct net *net, const struct nft_set *set, + const u32 *key) +{ + const struct nft_set_ext *ext; + unsigned int base_seq; + + do { + base_seq = nft_base_seq(net); + + ext = __nft_set_do_lookup(net, set, key); + if (ext) + break; + /* No match? There is a small chance that lookup was + * performed in the old generation, but nf_tables_commit() + * already unlinked a (matching) element. + * + * We need to repeat the lookup to make sure that we didn't + * miss a matching element in the new generation. + */ + } while (nft_lookup_should_retry(net, base_seq)); + + return ext; +} EXPORT_SYMBOL_GPL(nft_set_do_lookup); -#endif void nft_lookup_eval(const struct nft_expr *expr, struct nft_regs *regs, |