netfilter: nft_hash: add map lookups for hashing operations

This patch creates new attributes to accept a map as argument and
then perform the lookup with the generated hash accordingly.

Both current hash functions are supported: Jenkins and Symmetric Hash.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index ce031cf72288dfc5bbc50903c76d0915f9dec672..9c71f024f9cc466f1fa758d5f65b1d4e80420792 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -856,6 +856,8 @@ enum nft_hash_types {
  * @NFTA_HASH_SEED: seed value (NLA_U32)
  * @NFTA_HASH_OFFSET: add this offset value to hash result (NLA_U32)
  * @NFTA_HASH_TYPE: hash operation (NLA_U32: nft_hash_types)
+ * @NFTA_HASH_SET_NAME: name of the map to lookup (NLA_STRING)
+ * @NFTA_HASH_SET_ID: id of the map (NLA_U32)
  */
 enum nft_hash_attributes {
        NFTA_HASH_UNSPEC,
@@ -866,6 +868,8 @@ enum nft_hash_attributes {
        NFTA_HASH_SEED,
        NFTA_HASH_OFFSET,
        NFTA_HASH_TYPE,
+       NFTA_HASH_SET_NAME,
+       NFTA_HASH_SET_ID,
        __NFTA_HASH_MAX,
 };
 #define NFTA_HASH_MAX  (__NFTA_HASH_MAX - 1)

diff --git a/net/netfilter/nft_hash.c b/net/netfilter/nft_hash.c
index e235c17f1b8b7211d33d95f5a348bc7a6ed2046f..f0fc21f887753c6cc91be5ada551c12385cbb579 100644 (file)
--- a/net/netfilter/nft_hash.c
+++ b/net/netfilter/nft_hash.c
@@ -25,6 +25,7 @@ struct nft_jhash {
        u32                     modulus;
        u32                     seed;
        u32                     offset;
+       struct nft_set          *map;
 };
 
 static void nft_jhash_eval(const struct nft_expr *expr,
@@ -35,14 +36,39 @@ static void nft_jhash_eval(const struct nft_expr *expr,
        const void *data = &regs->data[priv->sreg];
        u32 h;
 
-       h = reciprocal_scale(jhash(data, priv->len, priv->seed), priv->modulus);
+       h = reciprocal_scale(jhash(data, priv->len, priv->seed),
+                            priv->modulus);
+
        regs->data[priv->dreg] = h + priv->offset;
 }
 
+static void nft_jhash_map_eval(const struct nft_expr *expr,
+                              struct nft_regs *regs,
+                              const struct nft_pktinfo *pkt)
+{
+       struct nft_jhash *priv = nft_expr_priv(expr);
+       const void *data = &regs->data[priv->sreg];
+       const struct nft_set *map = priv->map;
+       const struct nft_set_ext *ext;
+       u32 result;
+       bool found;
+
+       result = reciprocal_scale(jhash(data, priv->len, priv->seed),
+                                       priv->modulus) + priv->offset;
+
+       found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
+       if (!found)
+               return;
+
+       nft_data_copy(&regs->data[priv->dreg],
+                     nft_set_ext_data(ext), map->dlen);
+}
+
 struct nft_symhash {
        enum nft_registers      dreg:8;
        u32                     modulus;
        u32                     offset;
+       struct nft_set          *map;
 };
 
 static void nft_symhash_eval(const struct nft_expr *expr,
@@ -58,6 +84,28 @@ static void nft_symhash_eval(const struct nft_expr *expr,
        regs->data[priv->dreg] = h + priv->offset;
 }
 
+static void nft_symhash_map_eval(const struct nft_expr *expr,
+                                struct nft_regs *regs,
+                                const struct nft_pktinfo *pkt)
+{
+       struct nft_symhash *priv = nft_expr_priv(expr);
+       struct sk_buff *skb = pkt->skb;
+       const struct nft_set *map = priv->map;
+       const struct nft_set_ext *ext;
+       u32 result;
+       bool found;
+
+       result = reciprocal_scale(__skb_get_hash_symmetric(skb),
+                                 priv->modulus) + priv->offset;
+
+       found = map->ops->lookup(nft_net(pkt), map, &result, &ext);
+       if (!found)
+               return;
+
+       nft_data_copy(&regs->data[priv->dreg],
+                     nft_set_ext_data(ext), map->dlen);
+}
+
 static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
        [NFTA_HASH_SREG]        = { .type = NLA_U32 },
        [NFTA_HASH_DREG]        = { .type = NLA_U32 },
@@ -66,6 +114,9 @@ static const struct nla_policy nft_hash_policy[NFTA_HASH_MAX + 1] = {
        [NFTA_HASH_SEED]        = { .type = NLA_U32 },
        [NFTA_HASH_OFFSET]      = { .type = NLA_U32 },
        [NFTA_HASH_TYPE]        = { .type = NLA_U32 },
+       [NFTA_HASH_SET_NAME]    = { .type = NLA_STRING,
+                                   .len = NFT_SET_MAXNAMELEN - 1 },
+       [NFTA_HASH_SET_ID]      = { .type = NLA_U32 },
 };
 
 static int nft_jhash_init(const struct nft_ctx *ctx,
@@ -115,6 +166,23 @@ static int nft_jhash_init(const struct nft_ctx *ctx,
                                           NFT_DATA_VALUE, sizeof(u32));
 }
 
+static int nft_jhash_map_init(const struct nft_ctx *ctx,
+                             const struct nft_expr *expr,
+                             const struct nlattr * const tb[])
+{
+       struct nft_jhash *priv = nft_expr_priv(expr);
+       u8 genmask = nft_genmask_next(ctx->net);
+
+       nft_jhash_init(ctx, expr, tb);
+       priv->map = nft_set_lookup_global(ctx->net, ctx->table,
+                                         tb[NFTA_HASH_SET_NAME],
+                                         tb[NFTA_HASH_SET_ID], genmask);
+       if (IS_ERR(priv->map))
+               return PTR_ERR(priv->map);
+
+       return 0;
+}
+
 static int nft_symhash_init(const struct nft_ctx *ctx,
                            const struct nft_expr *expr,
                            const struct nlattr * const tb[])
@@ -141,6 +209,23 @@ static int nft_symhash_init(const struct nft_ctx *ctx,
                                           NFT_DATA_VALUE, sizeof(u32));
 }
 
+static int nft_symhash_map_init(const struct nft_ctx *ctx,
+                               const struct nft_expr *expr,
+                               const struct nlattr * const tb[])
+{
+       struct nft_jhash *priv = nft_expr_priv(expr);
+       u8 genmask = nft_genmask_next(ctx->net);
+
+       nft_symhash_init(ctx, expr, tb);
+       priv->map = nft_set_lookup_global(ctx->net, ctx->table,
+                                         tb[NFTA_HASH_SET_NAME],
+                                         tb[NFTA_HASH_SET_ID], genmask);
+       if (IS_ERR(priv->map))
+               return PTR_ERR(priv->map);
+
+       return 0;
+}
+
 static int nft_jhash_dump(struct sk_buff *skb,
                          const struct nft_expr *expr)
 {
@@ -168,6 +253,18 @@ nla_put_failure:
        return -1;
 }
 
+static int nft_jhash_map_dump(struct sk_buff *skb,
+                              const struct nft_expr *expr)
+{
+       const struct nft_jhash *priv = nft_expr_priv(expr);
+
+       if (nft_jhash_dump(skb, expr) ||
+           nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
+               return -1;
+
+       return 0;
+}
+
 static int nft_symhash_dump(struct sk_buff *skb,
                            const struct nft_expr *expr)
 {
@@ -188,6 +285,18 @@ nla_put_failure:
        return -1;
 }
 
+static int nft_symhash_map_dump(struct sk_buff *skb,
+                               const struct nft_expr *expr)
+{
+       const struct nft_symhash *priv = nft_expr_priv(expr);
+
+       if (nft_symhash_dump(skb, expr) ||
+           nla_put_string(skb, NFTA_HASH_SET_NAME, priv->map->name))
+               return -1;
+
+       return 0;
+}
+
 static struct nft_expr_type nft_hash_type;
 static const struct nft_expr_ops nft_jhash_ops = {
        .type           = &nft_hash_type,
@@ -197,6 +306,14 @@ static const struct nft_expr_ops nft_jhash_ops = {
        .dump           = nft_jhash_dump,
 };
 
+static const struct nft_expr_ops nft_jhash_map_ops = {
+       .type           = &nft_hash_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_jhash)),
+       .eval           = nft_jhash_map_eval,
+       .init           = nft_jhash_map_init,
+       .dump           = nft_jhash_map_dump,
+};
+
 static const struct nft_expr_ops nft_symhash_ops = {
        .type           = &nft_hash_type,
        .size           = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
@@ -205,6 +322,14 @@ static const struct nft_expr_ops nft_symhash_ops = {
        .dump           = nft_symhash_dump,
 };
 
+static const struct nft_expr_ops nft_symhash_map_ops = {
+       .type           = &nft_hash_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_symhash)),
+       .eval           = nft_symhash_map_eval,
+       .init           = nft_symhash_map_init,
+       .dump           = nft_symhash_map_dump,
+};
+
 static const struct nft_expr_ops *
 nft_hash_select_ops(const struct nft_ctx *ctx,
                    const struct nlattr * const tb[])
@@ -217,8 +342,12 @@ nft_hash_select_ops(const struct nft_ctx *ctx,
        type = ntohl(nla_get_be32(tb[NFTA_HASH_TYPE]));
        switch (type) {
        case NFT_HASH_SYM:
+               if (tb[NFTA_HASH_SET_NAME])
+                       return &nft_symhash_map_ops;
                return &nft_symhash_ops;
        case NFT_HASH_JENKINS:
+               if (tb[NFTA_HASH_SET_NAME])
+                       return &nft_jhash_map_ops;
                return &nft_jhash_ops;
        default:
                break;