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>
This commit is contained in:
Pablo Neira Ayuso 2015-08-02 14:16:42 +02:00
parent dba27ec1bc
commit f8d3a6bc76
1 changed files with 53 additions and 33 deletions

View File

@ -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 = {