Patchwork nftables: operational limit match

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Submitter Phil Oester
Date Oct. 5, 2013, 4:44 p.m.
Message ID <20131005164456.GB16881@home>
Download mbox | patch
Permalink /patch/280776/
State Accepted
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Comments

Phil Oester - Oct. 5, 2013, 4:44 p.m.
The nft limit match currently does not work at all.  Below patches to nftables,
libnftables, and kernel address the issue.  A few notes on the implementation:

- Removed support for nano/micro/milli second limits.  These seem pointless,
  given we are using jiffies in the limit match, not a hpet.  And who really
  needs to limit items down to sub-second level??

- 'depth' member is removed as unnecessary.  All we need in the kernel is the
  rate and the unit.  

- 'stamp' member becomes the time we need to next refresh the token bucket,
  instead of being updated on every packet which goes through the match.

This closes netfilter bugzilla #827, reported by Eric Leblond.

Signed-off-by: Phil Oester <kernel@linuxace.com>

diff --git a/include/libnftables/expr.h b/include/libnftables/expr.h
index b8f1d1e..232a810 100644
--- a/include/libnftables/expr.h
+++ b/include/libnftables/expr.h
@@ -134,7 +134,7 @@ enum {
 
 enum {
 	NFT_EXPR_LIMIT_RATE	= NFT_RULE_EXPR_ATTR_BASE,
-	NFT_EXPR_LIMIT_DEPTH,
+	NFT_EXPR_LIMIT_UNIT,
 };
 
 #ifdef __cplusplus
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index b690282..4ec8187 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -537,12 +537,12 @@ enum nft_ct_attributes {
  * enum nft_limit_attributes - nf_tables limit expression netlink attributes
  *
  * @NFTA_LIMIT_RATE: refill rate (NLA_U64)
- * @NFTA_LIMIT_DEPTH: bucket depth (NLA_U64)
+ * @NFTA_LIMIT_UNIT: refill unit (NLA_U64)
  */
 enum nft_limit_attributes {
 	NFTA_LIMIT_UNSPEC,
 	NFTA_LIMIT_RATE,
-	NFTA_LIMIT_DEPTH,
+	NFTA_LIMIT_UNIT,
 	__NFTA_LIMIT_MAX
 };
 #define NFTA_LIMIT_MAX		(__NFTA_LIMIT_MAX - 1)
diff --git a/src/expr/limit.c b/src/expr/limit.c
index 6954014..8c9d2ae 100644
--- a/src/expr/limit.c
+++ b/src/expr/limit.c
@@ -25,7 +25,7 @@
 
 struct nft_expr_limit {
 	uint64_t		rate;
-	uint64_t		depth;
+	uint64_t		unit;
 };
 
 static int
@@ -38,8 +38,8 @@ nft_rule_expr_limit_set(struct nft_rule_expr *e, uint16_t type,
 	case NFT_EXPR_LIMIT_RATE:
 		limit->rate = *((uint64_t *)data);
 		break;
-	case NFT_EXPR_LIMIT_DEPTH:
-		limit->depth = *((uint64_t *)data);
+	case NFT_EXPR_LIMIT_UNIT:
+		limit->unit = *((uint64_t *)data);
 		break;
 	default:
 		return -1;
@@ -57,9 +57,9 @@ nft_rule_expr_limit_get(const struct nft_rule_expr *e, uint16_t type,
 	case NFT_EXPR_LIMIT_RATE:
 		*data_len = sizeof(uint64_t);
 		return &limit->rate;
-	case NFT_EXPR_LIMIT_DEPTH:
+	case NFT_EXPR_LIMIT_UNIT:
 		*data_len = sizeof(uint64_t);
-		return &limit->depth;
+		return &limit->unit;
 	}
 	return NULL;
 }
@@ -74,7 +74,7 @@ static int nft_rule_expr_limit_cb(const struct nlattr *attr, void *data)
 
 	switch(type) {
 	case NFTA_LIMIT_RATE:
-	case NFTA_LIMIT_DEPTH:
+	case NFTA_LIMIT_UNIT:
 		if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
 			perror("mnl_attr_validate");
 			return MNL_CB_ERROR;
@@ -93,8 +93,8 @@ nft_rule_expr_limit_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
 
 	if (e->flags & (1 << NFT_EXPR_LIMIT_RATE))
 		mnl_attr_put_u64(nlh, NFTA_LIMIT_RATE, htobe64(limit->rate));
-	if (e->flags & (1 << NFT_EXPR_LIMIT_DEPTH))
-		mnl_attr_put_u64(nlh, NFTA_LIMIT_DEPTH, htobe64(limit->depth));
+	if (e->flags & (1 << NFT_EXPR_LIMIT_UNIT))
+		mnl_attr_put_u64(nlh, NFTA_LIMIT_UNIT, htobe64(limit->unit));
 }
 
 static int
@@ -110,9 +110,9 @@ nft_rule_expr_limit_parse(struct nft_rule_expr *e, struct nlattr *attr)
 		limit->rate = be64toh(mnl_attr_get_u64(tb[NFTA_LIMIT_RATE]));
 		e->flags |= (1 << NFT_EXPR_LIMIT_RATE);
 	}
-	if (tb[NFTA_LIMIT_DEPTH]) {
-		limit->depth = be64toh(mnl_attr_get_u64(tb[NFTA_LIMIT_DEPTH]));
-		e->flags |= (1 << NFT_EXPR_LIMIT_DEPTH);
+	if (tb[NFTA_LIMIT_UNIT]) {
+		limit->unit = be64toh(mnl_attr_get_u64(tb[NFTA_LIMIT_UNIT]));
+		e->flags |= (1 << NFT_EXPR_LIMIT_UNIT);
 	}
 
 	return 0;
@@ -128,10 +128,10 @@ static int nft_rule_expr_limit_json_parse(struct nft_rule_expr *e, json_t *root)
 
 	nft_rule_expr_set_u64(e, NFT_EXPR_LIMIT_RATE, uval64);
 
-	if (nft_jansson_parse_val(root, "depth", NFT_TYPE_U64, &uval64) < 0)
+	if (nft_jansson_parse_val(root, "unit", NFT_TYPE_U64, &uval64) < 0)
 		return -1;
 
-	nft_rule_expr_set_u64(e, NFT_EXPR_LIMIT_DEPTH, uval64);
+	nft_rule_expr_set_u64(e, NFT_EXPR_LIMIT_UNIT, uval64);
 
 	return 0;
 #else
@@ -151,11 +151,11 @@ static int nft_rule_expr_limit_xml_parse(struct nft_rule_expr *e, mxml_node_t *t
 
 	e->flags |= (1 << NFT_EXPR_LIMIT_RATE);
 
-	if (nft_mxml_num_parse(tree, "depth", MXML_DESCEND_FIRST, BASE_DEC,
-			       &limit->depth, NFT_TYPE_U64, NFT_XML_MAND) != 0)
+	if (nft_mxml_num_parse(tree, "unit", MXML_DESCEND_FIRST, BASE_DEC,
+			       &limit->unit, NFT_TYPE_U64, NFT_XML_MAND) != 0)
 		return -1;
 
-	e->flags |= (1 << NFT_EXPR_LIMIT_DEPTH);
+	e->flags |= (1 << NFT_EXPR_LIMIT_UNIT);
 
 	return 0;
 #else
@@ -169,19 +169,26 @@ nft_rule_expr_limit_snprintf(char *buf, size_t len, uint32_t type,
 			    uint32_t flags, struct nft_rule_expr *e)
 {
 	struct nft_expr_limit *limit = nft_expr_data(e);
+	static const char *units[] = {
+		[1]			= "second",
+		[1 * 60]		= "minute",
+		[1 * 60 * 60]		= "hour",
+		[1 * 60 * 60 * 24]	= "day",
+		[1 * 60 * 60 * 24 * 7]	= "week",
+	};
 
 	switch(type) {
 	case NFT_RULE_O_DEFAULT:
-		return snprintf(buf, len, "rate %"PRIu64" depth %"PRIu64" ",
-				limit->rate, limit->depth);
+		return snprintf(buf, len, "rate %"PRIu64"/%s ",
+				limit->rate, units[limit->unit]);
 	case NFT_RULE_O_XML:
 		return snprintf(buf, len, "<rate>%"PRIu64"</rate>"
-					  "<depth>%"PRIu64"</depth>",
-				limit->rate, limit->depth);
+					  "<unit>%"PRIu64"</unit>",
+				limit->rate, limit->unit);
 	case NFT_RULE_O_JSON:
 		return snprintf(buf, len, "\"rate\" : %"PRIu64", "
-					  "\"depth\" : %"PRIu64" ",
-				limit->rate, limit->depth);
+					  "\"unit\" : %"PRIu64" ",
+				limit->rate, limit->unit);
 	default:
 		break;
 	}
diff --git a/include/linux/netfilter/nf_tables.h b/include/linux/netfilter/nf_tables.h
index a236cc3..31dd907 100644
--- a/include/linux/netfilter/nf_tables.h
+++ b/include/linux/netfilter/nf_tables.h
@@ -544,12 +544,12 @@ enum nft_ct_attributes {
  * enum nft_limit_attributes - nf_tables limit expression netlink attributes
  *
  * @NFTA_LIMIT_RATE: refill rate (NLA_U64)
- * @NFTA_LIMIT_DEPTH: bucket depth (NLA_U64)
+ * @NFTA_LIMIT_UNIT: refill unit (NLA_U64)
  */
 enum nft_limit_attributes {
 	NFTA_LIMIT_UNSPEC,
 	NFTA_LIMIT_RATE,
-	NFTA_LIMIT_DEPTH,
+	NFTA_LIMIT_UNIT,
 	__NFTA_LIMIT_MAX
 };
 #define NFTA_LIMIT_MAX		(__NFTA_LIMIT_MAX - 1)
diff --git a/include/statement.h b/include/statement.h
index 5370231..6ecbb18 100644
--- a/include/statement.h
+++ b/include/statement.h
@@ -41,7 +41,6 @@ extern struct stmt *log_stmt_alloc(const struct location *loc);
 struct limit_stmt {
 	uint64_t		rate;
 	uint64_t		unit;
-	uint64_t		depth;
 };
 
 extern struct stmt *limit_stmt_alloc(const struct location *loc);
diff --git a/src/netlink_delinearize.c b/src/netlink_delinearize.c
index d80fc78..3bb143b 100644
--- a/src/netlink_delinearize.c
+++ b/src/netlink_delinearize.c
@@ -385,8 +385,8 @@ static void netlink_parse_limit(struct netlink_parse_ctx *ctx,
 	struct stmt *stmt;
 
 	stmt = limit_stmt_alloc(loc);
-	stmt->limit.rate  = nft_rule_expr_get_u32(nle, NFT_EXPR_LIMIT_RATE);
-	stmt->limit.depth  = nft_rule_expr_get_u32(nle, NFT_EXPR_LIMIT_DEPTH);
+	stmt->limit.rate  = nft_rule_expr_get_u64(nle, NFT_EXPR_LIMIT_RATE);
+	stmt->limit.unit  = nft_rule_expr_get_u64(nle, NFT_EXPR_LIMIT_UNIT);
 	list_add_tail(&stmt->list, &ctx->rule->stmts);
 }
 
diff --git a/src/netlink_linearize.c b/src/netlink_linearize.c
index 72c59e5..fd91155 100644
--- a/src/netlink_linearize.c
+++ b/src/netlink_linearize.c
@@ -551,8 +551,8 @@ static void netlink_gen_limit_stmt(struct netlink_linearize_ctx *ctx,
 	struct nft_rule_expr *nle;
 
 	nle = alloc_nft_expr("limit");
-	nft_rule_expr_set_u32(nle, NFT_EXPR_LIMIT_RATE, stmt->limit.rate);
-	nft_rule_expr_set_u32(nle, NFT_EXPR_LIMIT_DEPTH, stmt->limit.depth);
+	nft_rule_expr_set_u64(nle, NFT_EXPR_LIMIT_RATE, stmt->limit.rate);
+	nft_rule_expr_set_u64(nle, NFT_EXPR_LIMIT_UNIT, stmt->limit.unit);
 	nft_rule_add_expr(ctx->nlr, nle);
 }
 
diff --git a/src/parser.y b/src/parser.y
index 074f075..cfe1e86 100644
--- a/src/parser.y
+++ b/src/parser.y
@@ -1003,14 +1003,11 @@ limit_stmt		:	LIMIT	RATE	NUM	SLASH	time_unit
 			}
 			;
 
-time_unit		:	NANOSECOND	{ $$ = 1ULL; }
-			|	MICROSECOND	{ $$ = 1ULL * 1000; }
-			|	MILLISECOND	{ $$ = 1ULL * 1000 * 1000; }
-			|	SECOND		{ $$ = 1ULL * 1000 * 1000 * 1000; }
-			|	MINUTE		{ $$ = 1ULL * 1000 * 1000 * 1000 * 60; }
-			|	HOUR		{ $$ = 1ULL * 1000 * 1000 * 1000 * 60 * 60; }
-			|	DAY		{ $$ = 1ULL * 1000 * 1000 * 1000 * 60 * 60 * 24; }
-			|	WEEK		{ $$ = 1ULL * 1000 * 1000 * 1000 * 60 * 60 * 24 * 7; }
+time_unit		:	SECOND		{ $$ = 1ULL; }
+			|	MINUTE		{ $$ = 1ULL * 60; }
+			|	HOUR		{ $$ = 1ULL * 60 * 60; }
+			|	DAY		{ $$ = 1ULL * 60 * 60 * 24; }
+			|	WEEK		{ $$ = 1ULL * 60 * 60 * 24 * 7; }
 			;
 
 reject_stmt		:	_REJECT
diff --git a/src/statement.c b/src/statement.c
index 69db48f..658dc5f 100644
--- a/src/statement.c
+++ b/src/statement.c
@@ -144,8 +144,16 @@ struct stmt *log_stmt_alloc(const struct location *loc)
 
 static void limit_stmt_print(const struct stmt *stmt)
 {
-	printf("limit rate %" PRIu64 " depth %" PRIu64,
-	       stmt->limit.rate, stmt->limit.depth);
+	static const char *units[] = {
+		[1]			= "second",
+		[1 * 60]		= "minute",
+		[1 * 60 * 60]		= "hour",
+		[1 * 60 * 60 * 24]	= "day",
+		[1 * 60 * 60 * 24 * 7]	= "week",
+	};
+
+	printf("limit rate %" PRIu64 "/%s",
+	       stmt->limit.rate, units[stmt->limit.unit]);
 }
 
 static const struct stmt_ops limit_stmt_ops = {
Pablo Neira - Oct. 22, 2013, 8:55 a.m.
On Sat, Oct 05, 2013 at 09:44:56AM -0700, Phil Oester wrote:
> The nft limit match currently does not work at all.  Below patches to nftables,
> libnftables, and kernel address the issue.  A few notes on the implementation:
> 
> - Removed support for nano/micro/milli second limits.  These seem pointless,
>   given we are using jiffies in the limit match, not a hpet.  And who really
>   needs to limit items down to sub-second level??
> 
> - 'depth' member is removed as unnecessary.  All we need in the kernel is the
>   rate and the unit.  
> 
> - 'stamp' member becomes the time we need to next refresh the token bucket,
>   instead of being updated on every packet which goes through the match.
> 
> This closes netfilter bugzilla #827, reported by Eric Leblond.

Applied the userspace chunks to libnftables and nftables, please split
this in three patches next time. The kernel chunk was merged into the
nftables pull request.

Thanks.
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Patch

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index b8cd62f..a652136 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -538,12 +538,12 @@  enum nft_ct_attributes {
  * enum nft_limit_attributes - nf_tables limit expression netlink attributes
  *
  * @NFTA_LIMIT_RATE: refill rate (NLA_U64)
- * @NFTA_LIMIT_DEPTH: bucket depth (NLA_U64)
+ * @NFTA_LIMIT_UNIT: refill unit (NLA_U64)
  */
 enum nft_limit_attributes {
 	NFTA_LIMIT_UNSPEC,
 	NFTA_LIMIT_RATE,
-	NFTA_LIMIT_DEPTH,
+	NFTA_LIMIT_UNIT,
 	__NFTA_LIMIT_MAX
 };
 #define NFTA_LIMIT_MAX		(__NFTA_LIMIT_MAX - 1)
diff --git a/net/netfilter/nft_limit.c b/net/netfilter/nft_limit.c
index a40ccc0..85da5bd 100644
--- a/net/netfilter/nft_limit.c
+++ b/net/netfilter/nft_limit.c
@@ -21,8 +21,8 @@  static DEFINE_SPINLOCK(limit_lock);
 
 struct nft_limit {
 	u64		tokens;
-	u64		depth;
 	u64		rate;
+	u64		unit;
 	unsigned long	stamp;
 };
 
@@ -33,11 +33,9 @@  static void nft_limit_eval(const struct nft_expr *expr,
 	struct nft_limit *priv = nft_expr_priv(expr);
 
 	spin_lock_bh(&limit_lock);
-	if (priv->stamp != jiffies) {
-		priv->tokens += priv->rate * (jiffies - priv->stamp);
-		if (priv->tokens > priv->depth)
-			priv->tokens = priv->depth;
-		priv->stamp = jiffies;
+	if (time_after_eq(jiffies, priv->stamp)) {
+		priv->tokens = priv->rate;
+		priv->stamp = jiffies + priv->unit * HZ;
 	}
 
 	if (priv->tokens >= 1) {
@@ -52,7 +50,7 @@  static void nft_limit_eval(const struct nft_expr *expr,
 
 static const struct nla_policy nft_limit_policy[NFTA_LIMIT_MAX + 1] = {
 	[NFTA_LIMIT_RATE]	= { .type = NLA_U64 },
-	[NFTA_LIMIT_DEPTH]	= { .type = NLA_U64 },
+	[NFTA_LIMIT_UNIT]	= { .type = NLA_U64 },
 };
 
 static int nft_limit_init(const struct nft_ctx *ctx,
@@ -62,12 +60,13 @@  static int nft_limit_init(const struct nft_ctx *ctx,
 	struct nft_limit *priv = nft_expr_priv(expr);
 
 	if (tb[NFTA_LIMIT_RATE] == NULL ||
-	    tb[NFTA_LIMIT_DEPTH] == NULL)
+	    tb[NFTA_LIMIT_UNIT] == NULL)
 		return -EINVAL;
 
 	priv->rate   = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_RATE]));
-	priv->depth  = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_DEPTH]));
-	priv->tokens = priv->depth;
+	priv->unit   = be64_to_cpu(nla_get_be64(tb[NFTA_LIMIT_UNIT]));
+	priv->stamp  = jiffies + priv->unit * HZ;
+	priv->tokens = priv->rate;
 	return 0;
 }
 
@@ -77,7 +76,7 @@  static int nft_limit_dump(struct sk_buff *skb, const struct nft_expr *expr)
 
 	if (nla_put_be64(skb, NFTA_LIMIT_RATE, cpu_to_be64(priv->rate)))
 		goto nla_put_failure;
-	if (nla_put_be64(skb, NFTA_LIMIT_DEPTH, cpu_to_be64(priv->depth)))
+	if (nla_put_be64(skb, NFTA_LIMIT_UNIT, cpu_to_be64(priv->unit)))
 		goto nla_put_failure;
 	return 0;