netfilter: nft_numgen: add map lookups for numgen random operations

This patch uses the map lookup already included to be applied
for random number generation.

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

diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c
index 8a64db8f2e69d900adb1a98caf08587f30c00f62..cdbc62a53933e5940ce2049af61ab0d453f8962d 100644 (file)
--- a/net/netfilter/nft_numgen.c
+++ b/net/netfilter/nft_numgen.c
@@ -166,18 +166,43 @@ struct nft_ng_random {
        enum nft_registers      dreg:8;
        u32                     modulus;
        u32                     offset;
+       struct nft_set          *map;
 };
 
+static u32 nft_ng_random_gen(struct nft_ng_random *priv)
+{
+       struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
+
+       return reciprocal_scale(prandom_u32_state(state), priv->modulus) +
+              priv->offset;
+}
+
 static void nft_ng_random_eval(const struct nft_expr *expr,
                               struct nft_regs *regs,
                               const struct nft_pktinfo *pkt)
 {
        struct nft_ng_random *priv = nft_expr_priv(expr);
-       struct rnd_state *state = this_cpu_ptr(&nft_numgen_prandom_state);
-       u32 val;
 
-       val = reciprocal_scale(prandom_u32_state(state), priv->modulus);
-       regs->data[priv->dreg] = val + priv->offset;
+       regs->data[priv->dreg] = nft_ng_random_gen(priv);
+}
+
+static void nft_ng_random_map_eval(const struct nft_expr *expr,
+                                  struct nft_regs *regs,
+                                  const struct nft_pktinfo *pkt)
+{
+       struct nft_ng_random *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_random_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 int nft_ng_random_init(const struct nft_ctx *ctx,
@@ -204,6 +229,23 @@ static int nft_ng_random_init(const struct nft_ctx *ctx,
                                           NFT_DATA_VALUE, sizeof(u32));
 }
 
+static int nft_ng_random_map_init(const struct nft_ctx *ctx,
+                                 const struct nft_expr *expr,
+                                 const struct nlattr * const tb[])
+{
+       struct nft_ng_random *priv = nft_expr_priv(expr);
+       u8 genmask = nft_genmask_next(ctx->net);
+
+       nft_ng_random_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_random_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
        const struct nft_ng_random *priv = nft_expr_priv(expr);
@@ -212,6 +254,22 @@ static int nft_ng_random_dump(struct sk_buff *skb, const struct nft_expr *expr)
                           priv->offset);
 }
 
+static int nft_ng_random_map_dump(struct sk_buff *skb,
+                                 const struct nft_expr *expr)
+{
+       const struct nft_ng_random *priv = nft_expr_priv(expr);
+
+       if (nft_ng_dump(skb, priv->dreg, priv->modulus,
+                       NFT_NG_RANDOM, priv->offset) ||
+           nla_put_string(skb, NFTA_NG_SET_NAME, priv->map->name))
+               goto nla_put_failure;
+
+       return 0;
+
+nla_put_failure:
+       return -1;
+}
+
 static struct nft_expr_type nft_ng_type;
 static const struct nft_expr_ops nft_ng_inc_ops = {
        .type           = &nft_ng_type,
@@ -237,6 +295,14 @@ static const struct nft_expr_ops nft_ng_random_ops = {
        .dump           = nft_ng_random_dump,
 };
 
+static const struct nft_expr_ops nft_ng_random_map_ops = {
+       .type           = &nft_ng_type,
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
+       .eval           = nft_ng_random_map_eval,
+       .init           = nft_ng_random_map_init,
+       .dump           = nft_ng_random_map_dump,
+};
+
 static const struct nft_expr_ops *
 nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
 {
@@ -255,6 +321,8 @@ nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
                        return &nft_ng_inc_map_ops;
                return &nft_ng_inc_ops;
        case NFT_NG_RANDOM:
+               if (tb[NFTA_NG_SET_NAME])
+                       return &nft_ng_random_map_ops;
                return &nft_ng_random_ops;
        }