netfilter: nft_hash: convert to use rhashtable callbacks

A following patch will convert sets to use so called set extensions,
where the key is not located in a fixed position anymore. This will
require rhashtable hashing and comparison callbacks to be used.

As preparation, convert nft_hash to use these callbacks without any
functional changes.

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

1 files changed, 49 insertions, 5 deletions

diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index e35f0b2d8e65..dc96a7e94f80 100644
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -33,16 +33,50 @@ struct nft_hash_elem {
         struct nft_data                 data[];
 };
 
+struct nft_hash_cmp_arg {
+        const struct nft_set            *set;
+        const struct nft_data           *key;
+};
+
 static const struct rhashtable_params nft_hash_params;
 
+static inline u32 nft_hash_key(const void *data, u32 len, u32 seed)
+{
+        const struct nft_hash_cmp_arg *arg = data;
+
+        return jhash(arg->key, len, seed);
+}
+
+static inline u32 nft_hash_obj(const void *data, u32 len, u32 seed)
+{
+        const struct nft_hash_elem *he = data;
+
+        return jhash(&he->key, len, seed);
+}
+
+static inline int nft_hash_cmp(struct rhashtable_compare_arg *arg,
+                               const void *ptr)
+{
+        const struct nft_hash_cmp_arg *x = arg->key;
+        const struct nft_hash_elem *he = ptr;
+
+        if (nft_data_cmp(&he->key, x->key, x->set->klen))
+                return 1;
+        return 0;
+}
+
 static bool nft_hash_lookup(const struct nft_set *set,
                             const struct nft_data *key,
                             struct nft_data *data)
 {
         struct nft_hash *priv = nft_set_priv(set);
         const struct nft_hash_elem *he;
+        struct nft_hash_cmp_arg arg = {
+                .set     = set,
+                .key     = key,
+        };
 
-        he = rhashtable_lookup_fast(&priv->ht, key, nft_hash_params);
+        he = rhashtable_lookup_fast(&priv->ht, &arg, nft_hash_params);
         if (he && set->flags & NFT_SET_MAP)
                 nft_data_copy(data, he->data);
 
@@ -54,6 +88,10 @@ static int nft_hash_insert(const struct nft_set *set,
 {
         struct nft_hash *priv = nft_set_priv(set);
         struct nft_hash_elem *he;
+        struct nft_hash_cmp_arg arg = {
+                .set     = set,
+                .key     = &elem->key,
+        };
         unsigned int size;
         int err;
 
@@ -72,7 +110,8 @@ static int nft_hash_insert(const struct nft_set *set,
         if (set->flags & NFT_SET_MAP)
                 nft_data_copy(he->data, &elem->data);
 
-        err = rhashtable_insert_fast(&priv->ht, &he->node, nft_hash_params);
+        err = rhashtable_lookup_insert_key(&priv->ht, &arg, &he->node,
+                                           nft_hash_params);
         if (err)
                 kfree(he);
 
@@ -102,8 +141,12 @@ static int nft_hash_get(const struct nft_set *set, struct nft_set_elem *elem)
 {
         struct nft_hash *priv = nft_set_priv(set);
         struct nft_hash_elem *he;
+        struct nft_hash_cmp_arg arg = {
+                .set     = set,
+                .key     = &elem->key,
+        };
 
-        he = rhashtable_lookup_fast(&priv->ht, &elem->key, nft_hash_params);
+        he = rhashtable_lookup_fast(&priv->ht, &arg, nft_hash_params);
         if (!he)
                 return -ENOENT;
 
@@ -174,8 +217,9 @@ static unsigned int nft_hash_privsize(const struct nlattr * const nla[])
 
 static const struct rhashtable_params nft_hash_params = {
         .head_offset            = offsetof(struct nft_hash_elem, node),
-        .key_offset             = offsetof(struct nft_hash_elem, key),
-        .hashfn                 = jhash,
+        .hashfn                 = nft_hash_key,
+        .obj_hashfn             = nft_hash_obj,
+        .obj_cmpfn              = nft_hash_cmp,
         .automatic_shrinking    = true,
 };