netfilter: nft_limit: constant token cost per packet

The cost per packet can be calculated from the control plane path since this
doesn't ever change.

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

diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c
index d8c5ff1..b418698 100644 (file)
--- a/net/netfilter/nft_limit.c
+++ b/net/netfilter/nft_limit.c
@@ -98,13 +98,18 @@ nla_put_failure:
        return -1;
 }
 
+struct nft_limit_pkts {
+       struct nft_limit        limit;
+       u64                     cost;
+};
+
 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);
+       struct nft_limit_pkts *priv = nft_expr_priv(expr);
 
-       if (nft_limit_eval(priv, div_u64(priv->nsecs, priv->rate)))
+       if (nft_limit_eval(&priv->limit, priv->cost))
                regs->verdict.code = NFT_BREAK;
 }
 
@@ -118,22 +123,28 @@ 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);
+       struct nft_limit_pkts *priv = nft_expr_priv(expr);
+       int err;
 
-       return nft_limit_init(priv, tb);
+       err = nft_limit_init(&priv->limit, tb);
+       if (err < 0)
+               return err;
+
+       priv->cost = div_u64(priv->limit.nsecs, priv->limit.rate);
+       return 0;
 }
 
 static int nft_limit_pkts_dump(struct sk_buff *skb, const struct nft_expr *expr)
 {
-       const struct nft_limit *priv = nft_expr_priv(expr);
+       const struct nft_limit_pkts *priv = nft_expr_priv(expr);
 
-       return nft_limit_dump(skb, priv);
+       return nft_limit_dump(skb, &priv->limit);
 }
 
 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)),
+       .size           = NFT_EXPR_SIZE(sizeof(struct nft_limit_pkts)),
        .eval           = nft_limit_pkts_eval,
        .init           = nft_limit_pkts_init,
        .dump           = nft_limit_pkts_dump,