expr: add limit

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

1 files changed, 213 insertions, 0 deletions

diff --git a/src/expr/limit.c b/src/expr/limit.c
new file mode 100644
index 0000000..64a5b70
--- /dev/null
+++ b/src/expr/limit.c
@@ -0,0 +1,213 @@
+/*
+ * (C) 2012-2013 by Pablo Neira Ayuso <pablo@netfilter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published
+ * by the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This code has been sponsored by Sophos Astaro <http://www.sophos.com>
+ */
+
+#include <stdio.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <arpa/inet.h>
+#include <errno.h>
+#include <linux/netfilter/nf_tables.h>
+
+#include "internal.h"
+#include <libmnl/libmnl.h>
+#include <libnftables/expr.h>
+#include <libnftables/rule.h>
+#include "expr_ops.h"
+
+struct nft_expr_limit {
+	uint64_t		rate;
+	uint64_t		depth;
+};
+
+static int
+nft_rule_expr_limit_set(struct nft_rule_expr *e, uint16_t type,
+		       const void *data, size_t data_len)
+{
+	struct nft_expr_limit *limit = (struct nft_expr_limit *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_LIMIT_RATE:
+		limit->rate = *((uint64_t *)data);
+		break;
+	case NFT_EXPR_LIMIT_DEPTH:
+		limit->depth = *((uint64_t *)data);
+		break;
+	default:
+		return -1;
+	}
+	return 0;
+}
+
+static const void *
+nft_rule_expr_limit_get(struct nft_rule_expr *e, uint16_t type, size_t *data_len)
+{
+	struct nft_expr_limit *limit = (struct nft_expr_limit *)e->data;
+
+	switch(type) {
+	case NFT_EXPR_LIMIT_RATE:
+		if (e->flags & (1 << NFT_EXPR_LIMIT_RATE))
+			return &limit->rate;
+		else
+			return NULL;
+		break;
+	case NFT_EXPR_LIMIT_DEPTH:
+		if (e->flags & (1 << NFT_EXPR_LIMIT_DEPTH))
+			return &limit->depth;
+		else
+			return NULL;
+		break;
+	default:
+		break;
+	}
+	return NULL;
+}
+
+static int nft_rule_expr_limit_cb(const struct nlattr *attr, void *data)
+{
+	const struct nlattr **tb = data;
+	int type = mnl_attr_get_type(attr);
+
+	if (mnl_attr_type_valid(attr, NFTA_LIMIT_MAX) < 0)
+		return MNL_CB_OK;
+
+	switch(type) {
+	case NFTA_LIMIT_RATE:
+	case NFTA_LIMIT_DEPTH:
+		if (mnl_attr_validate(attr, MNL_TYPE_U64) < 0) {
+			perror("mnl_attr_validate");
+			return MNL_CB_ERROR;
+		}
+		break;
+	}
+
+	tb[type] = attr;
+	return MNL_CB_OK;
+}
+
+static void
+nft_rule_expr_limit_build(struct nlmsghdr *nlh, struct nft_rule_expr *e)
+{
+	struct nft_expr_limit *limit = (struct nft_expr_limit *)e->data;
+
+	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));
+}
+
+static int
+nft_rule_expr_limit_parse(struct nft_rule_expr *e, struct nlattr *attr)
+{
+	struct nft_expr_limit *limit = (struct nft_expr_limit *)e->data;
+	struct nlattr *tb[NFTA_LIMIT_MAX+1] = {};
+
+	if (mnl_attr_parse_nested(attr, nft_rule_expr_limit_cb, tb) < 0)
+		return -1;
+
+	if (tb[NFTA_LIMIT_RATE]) {
+		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);
+	}
+
+	return 0;
+}
+
+static int nft_rule_expr_limit_xml_parse(struct nft_rule_expr *e, char *xml)
+{
+#ifdef XML_PARSING
+	struct nft_expr_limit *limit = (struct nft_expr_limit *)e->data;
+	mxml_node_t *tree = NULL;
+	mxml_node_t *node = NULL;
+	uint64_t tmp;
+	char *endptr;
+
+	tree = mxmlLoadString(NULL, xml, MXML_OPAQUE_CALLBACK);
+	if (tree == NULL)
+		return -1;
+
+	if (mxmlElementGetAttr(tree, "type") == NULL)
+		goto err;
+
+	if (strcmp("limit", mxmlElementGetAttr(tree, "type")) != 0)
+		goto err;
+
+	node = mxmlFindElement(tree, tree, "rate", NULL, NULL,
+			       MXML_DESCEND_FIRST);
+	if (node == NULL)
+		goto err;
+
+	tmp = strtoull(node->child->value.opaque, &endptr, 10);
+	if (tmp > UINT64_MAX || tmp < 0 || *endptr)
+		goto err;
+
+	limit->rate = tmp;
+	e->flags |= (1 << NFT_EXPR_LIMIT_RATE);
+
+	node = mxmlFindElement(tree, tree, "depth", NULL, NULL,
+			       MXML_DESCEND);
+	if (node == NULL)
+		goto err;
+
+	tmp = strtoull(node->child->value.opaque, &endptr, 10);
+	if (tmp > UINT64_MAX || tmp < 0 || *endptr)
+		goto err;
+
+	limit->depth = tmp;
+	e->flags |= (1 << NFT_EXPR_LIMIT_DEPTH);
+
+	mxmlDelete(tree);
+	return 0;
+err:
+	errno = EINVAL;
+	mxmlDelete(tree);
+	return -1;
+#else
+	errno = EOPNOTSUPP;
+	return -1;
+#endif
+}
+
+static int
+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 = (struct nft_expr_limit *)e->data;
+
+	switch(type) {
+	case NFT_RULE_O_DEFAULT:
+		return snprintf(buf, len, "rate=%"PRIu64" depth=%"PRIu64" ",
+				limit->rate, limit->depth);
+	case NFT_RULE_O_XML:
+		return snprintf(buf, len, "<rate>%"PRIu64"</rate>"
+					  "<depth>%"PRIu64"</depth>",
+				limit->rate, limit->depth);
+	default:
+		break;
+	}
+	return -1;
+}
+
+struct expr_ops expr_ops_limit = {
+	.name		= "limit",
+	.alloc_len	= sizeof(struct nft_expr_limit),
+	.max_attr	= NFTA_LIMIT_MAX,
+	.set		= nft_rule_expr_limit_set,
+	.get		= nft_rule_expr_limit_get,
+	.parse		= nft_rule_expr_limit_parse,
+	.build		= nft_rule_expr_limit_build,
+	.snprintf	= nft_rule_expr_limit_snprintf,
+	.xml_parse	= nft_rule_expr_limit_xml_parse,
+};