netfilter: nft_numgen: add map lookups for numgen statements

This patch includes a new attribute in the numgen structure to allow
the lookup of an element based on the number generator as a key.

For this purpose, different ops have been included to extend the
current numgen inc functions.

Currently, only supported for numgen incremental operations, but
it will be supported for random in a follow-up patch.

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 6a3d653..5a5551a 100644 (file)
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1450,6 +1450,8 @@ enum nft_trace_types {
  * @NFTA_NG_MODULUS: maximum counter value (NLA_U32)
  * @NFTA_NG_TYPE: operation type (NLA_U32)
  * @NFTA_NG_OFFSET: offset to be added to the counter (NLA_U32)
+ * @NFTA_NG_SET_NAME: name of the map to lookup (NLA_STRING)
+ * @NFTA_NG_SET_ID: id of the map (NLA_U32)
  */
 enum nft_ng_attributes {
        NFTA_NG_UNSPEC,
@@ -1457,6 +1459,8 @@ enum nft_ng_attributes {
        NFTA_NG_MODULUS,
        NFTA_NG_TYPE,
        NFTA_NG_OFFSET,
+       NFTA_NG_SET_NAME,
+       NFTA_NG_SET_ID,
        __NFTA_NG_MAX
 };
 #define NFTA_NG_MAX    (__NFTA_NG_MAX - 1)

diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c
index 5a3a52c..8a64db8 100644 (file)
--- a/net/netfilter/nft_numgen.c
+++ b/net/netfilter/nft_numgen.c
@@ -24,13 +24,11 @@ struct nft_ng_inc {
        u32                     modulus;
        atomic_t                counter;
        u32                     offset;
+       struct nft_set          *map;
 };
 
-static void nft_ng_inc_eval(const struct nft_expr *expr,
-                           struct nft_regs *regs,
-                           const struct nft_pktinfo *pkt)
+static u32 nft_ng_inc_gen(struct nft_ng_inc *priv)
 {
-       struct nft_ng_inc *priv = nft_expr_priv(expr);
        u32 nval, oval;
 
        do {
@@ -38,7 +36,36 @@ static void nft_ng_inc_eval(const struct nft_expr *expr,
                nval = (oval + 1 < priv->modulus) ? oval + 1 : 0;
        } while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);
 
-       regs->data[priv->dreg] = nval + priv->offset;
+       return nval + priv->offset;
+}
+
+static void nft_ng_inc_eval(const struct nft_expr *expr,
+                           struct nft_regs *regs,
+                           const struct nft_pktinfo *pkt)
+{
+       struct nft_ng_inc *priv = nft_expr_priv(expr);
+
+       regs->data[priv->dreg] = nft_ng_inc_gen(priv);
+}
+
+static void nft_ng_inc_map_eval(const struct nft_expr *expr,
+                               struct nft_regs *regs,
+                               const struct nft_pktinfo *pkt)
+{
+       struct nft_ng_inc *priv = nft_expr_priv(expr);
+       const struct nft_set *map = priv->map;
+       const struct nft_set_ext *ext;
+       u32 result;
+       bool found;
+
+       result = nft_ng_inc_gen(priv);
+       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_ng_policy[NFTA_NG_MAX + 1] = {
@@ -46,6 +73,9 @@ static const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
        [NFTA_NG_MODULUS]       = { .type = NLA_U32 },
        [NFTA_NG_TYPE]          = { .type = NLA_U32 },
        [NFTA_NG_OFFSET]        = { .type = NLA_U32 },
+       [NFTA_NG_SET_NAME]      = { .type = NLA_STRING,
+                                   .len = NFT_SET_MAXNAMELEN - 1 },
+       [NFTA_NG_SET_ID]        = { .type = NLA_U32 },
 };
 
 static int nft_ng_inc_init(const struct nft_ctx *ctx,
@@ -71,6 +101,25 @@ static int nft_ng_inc_init(const struct nft_ctx *ctx,
                                           NFT_DATA_VALUE, sizeof(u32));
 }
 
+static int nft_ng_inc_map_init(const struct nft_ctx *ctx,
+                              const struct nft_expr *expr,
+                              const struct nlattr * const tb[])
+{
+       struct nft_ng_inc *priv = nft_expr_priv(expr);
+       u8 genmask = nft_genmask_next(ctx->net);
+
+       nft_ng_inc_init(ctx, expr, tb);
+
+       priv->map = nft_set_lookup_global(ctx->net, ctx->table,
+                                         tb[NFTA_NG_SET_NAME],
+                                         tb[NFTA_NG_SET_ID], genmask);
+
+       if (IS_ERR(priv->map))
+               return PTR_ERR(priv->map);
+
+       return 0;
+}
+
 static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
                       u32 modulus, enum nft_ng_types type, u32 offset)
 {
@@ -97,6 +146,22 @@ static int nft_ng_inc_dump(struct sk_buff *skb, const struct nft_expr *expr)
                           priv->offset);
 }
 
+static int nft_ng_inc_map_dump(struct sk_buff *skb,
+                              const struct nft_expr *expr)
+{
+       const struct nft_ng_inc *priv = nft_expr_priv(expr);
+
+       if (nft_ng_dump(skb, priv->dreg, priv->modulus,
+                       NFT_NG_INCREMENTAL, priv->offset) ||
+           nla_put_string(skb, NFTA_NG_SET_NAME, priv->map->name))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
 struct nft_ng_random {
        enum nft_registers      dreg:8;
        u32                     modulus;
@@ -156,6 +221,14 @@ static const struct nft_expr_ops nft_ng_inc_ops = {
        .dump           = nft_ng_inc_dump,
 };
 
+static const struct nft_expr_ops nft_ng_inc_map_ops = {
+       .type           = &nft_ng_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
+       .eval           = nft_ng_inc_map_eval,
+       .init           = nft_ng_inc_map_init,
+       .dump           = nft_ng_inc_map_dump,
+};
+
 static const struct nft_expr_ops nft_ng_random_ops = {
        .type           = &nft_ng_type,
        .size           = NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
@@ -178,6 +251,8 @@ nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
 
        switch (type) {
        case NFT_NG_INCREMENTAL:
+               if (tb[NFTA_NG_SET_NAME])
+                       return &nft_ng_inc_map_ops;
                return &nft_ng_inc_ops;
        case NFT_NG_RANDOM:
                return &nft_ng_random_ops;