netfilter: nft_limit: factor out shared code with per-byte limiting

This patch prepares the introduction of per-byte limiting.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c
index c79703e..c4d1b1b 100644 (file)
--- a/net/netfilter/nft_limit.c
+++ b/net/netfilter/nft_limit.c
@@ -27,65 +27,54 @@ struct nft_limit {
        u64             nsecs;
 };
 
-static void nft_limit_pkts_eval(const struct nft_expr *expr,
-                               struct nft_regs *regs,
-                               const struct nft_pktinfo *pkt)
+static inline bool nft_limit_eval(struct nft_limit *limit, u64 cost)
 {
-       struct nft_limit *priv = nft_expr_priv(expr);
-       u64 now, tokens, cost = div_u64(priv->nsecs, priv->rate);
+       u64 now, tokens;
        s64 delta;
 
        spin_lock_bh(&limit_lock);
        now = ktime_get_ns();
-       tokens = priv->tokens + now - priv->last;
-       if (tokens > priv->tokens_max)
-               tokens = priv->tokens_max;
+       tokens = limit->tokens + now - limit->last;
+       if (tokens > limit->tokens_max)
+               tokens = limit->tokens_max;
 
-       priv->last = now;
+       limit->last = now;
        delta = tokens - cost;
        if (delta >= 0) {
-               priv->tokens = delta;
+               limit->tokens = delta;
                spin_unlock_bh(&limit_lock);
-               return;
+               return false;
        }
-       priv->tokens = tokens;
+       limit->tokens = tokens;
        spin_unlock_bh(&limit_lock);
-
-       regs->verdict.code = NFT_BREAK;
+       return true;
 }
 
-static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
-       [NFTA_LIMIT_RATE]       = { .type = NLA_U64 },
-       [NFTA_LIMIT_UNIT]       = { .type = NLA_U64 },
-};
-
-static int nft_limit_init(const struct nft_ctx *ctx,
-                         const struct nft_expr *expr,
+static int nft_limit_init(struct nft_limit *limit,
                          const struct nlattr * const tb[])
 {
-       struct nft_limit *priv = nft_expr_priv(expr);
        u64 unit;
 
        if (tb[NFTA_LIMIT_RATE] == NULL ||
            tb[NFTA_LIMIT_UNIT] == NULL)
                return -EINVAL;
 
-       priv->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
+       limit->rate = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
        unit = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
-       priv->nsecs = unit * NSEC_PER_SEC;
-       if (priv->rate == 0 || priv->nsecs < unit)
+       limit->nsecs = unit * NSEC_PER_SEC;
+       if (limit->rate == 0 || limit->nsecs < unit)
                return -EOVERFLOW;
-       priv->tokens = priv->tokens_max = priv->nsecs;
-       priv->last = ktime_get_ns();
+       limit->tokens = limit->tokens_max = limit->nsecs;
+       limit->last = ktime_get_ns();
+
        return 0;
 }
 
-static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr)
+static int nft_limit_dump(struct sk_buff *skb, const struct nft_limit *limit)
 {
-       const struct nft_limit *priv = nft_expr_priv(expr);
-       u64 secs = div_u64(priv->nsecs, NSEC_PER_SEC);
+       u64 secs = div_u64(limit->nsecs, NSEC_PER_SEC);
 
-       if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate)) ||
+       if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(limit->rate)) ||
            nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(secs)))
                goto nla_put_failure;
        return 0;
@@ -94,13 +83,44 @@ nla_put_failure:
        return -1;
 }
 
+static void nft_limit_pkts_eval(const struct nft_expr *expr,
+                               struct nft_regs *regs,
+                               const struct nft_pktinfo *pkt)
+{
+       struct nft_limit *priv = nft_expr_priv(expr);
+
+       if (nft_limit_eval(priv, div_u64(priv->nsecs, priv->rate)))
+               regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
+       [NFTA_LIMIT_RATE]       = { .type = NLA_U64 },
+       [NFTA_LIMIT_UNIT]       = { .type = NLA_U64 },
+};
+
+static int nft_limit_pkts_init(const struct nft_ctx *ctx,
+                              const struct nft_expr *expr,
+                              const struct nlattr * const tb[])
+{
+       struct nft_limit *priv = nft_expr_priv(expr);
+
+       return nft_limit_init(priv, tb);
+}
+
+static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+       const struct nft_limit *priv = nft_expr_priv(expr);
+
+       return nft_limit_dump(skb, priv);
+}
+
 static struct nft_expr_type nft_limit_type;
 static const struct nft_expr_ops nft_limit_pkts_ops = {
        .type           = &nft_limit_type,
        .size           = NFT_EXPR_SIZE(sizeof(struct nft_limit)),
        .eval           = nft_limit_pkts_eval,
-       .init           = nft_limit_init,
-       .dump           = nft_limit_dump,
+       .init           = nft_limit_pkts_init,
+       .dump           = nft_limit_pkts_dump,
 };
 
 static struct nft_expr_type nft_limit_type __read_mostly = {