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Message-Id: <1474844823-2026-52-git-send-email-pablo@netfilter.org>
Date: Mon, 26 Sep 2016 01:07:01 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 51/53] netfilter: nf_tables: add range expression
Inverse ranges != [a,b] are not currently possible because rules are
composites of && operations, and we need to express this:
data < a || data > b
This patch adds a new range expression. Positive ranges can be already
through two cmp expressions:
cmp(sreg, data, >=)
cmp(sreg, data, <=)
This new range expression provides an alternative way to express this.
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_tables_core.h | 3 +
include/uapi/linux/netfilter/nf_tables.h | 29 +++++++
net/netfilter/Makefile | 3 +-
net/netfilter/nf_tables_core.c | 7 +-
net/netfilter/nft_range.c | 138 +++++++++++++++++++++++++++++++
5 files changed, 178 insertions(+), 2 deletions(-)
create mode 100644 net/netfilter/nft_range.c
diff --git a/include/net/netfilter/nf_tables_core.h b/include/net/netfilter/nf_tables_core.h
index a9060dd99db7..00f4f6b1b1ba 100644
--- a/include/net/netfilter/nf_tables_core.h
+++ b/include/net/netfilter/nf_tables_core.h
@@ -28,6 +28,9 @@ extern const struct nft_expr_ops nft_cmp_fast_ops;
int nft_cmp_module_init(void);
void nft_cmp_module_exit(void);
+int nft_range_module_init(void);
+void nft_range_module_exit(void);
+
int nft_lookup_module_init(void);
void nft_lookup_module_exit(void);
diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index 1cf41dd838b2..c6c4477c136b 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -546,6 +546,35 @@ enum nft_cmp_attributes {
};
#define NFTA_CMP_MAX (__NFTA_CMP_MAX - 1)
+/**
+ * enum nft_range_ops - nf_tables range operator
+ *
+ * @NFT_RANGE_EQ: equal
+ * @NFT_RANGE_NEQ: not equal
+ */
+enum nft_range_ops {
+ NFT_RANGE_EQ,
+ NFT_RANGE_NEQ,
+};
+
+/**
+ * enum nft_range_attributes - nf_tables range expression netlink attributes
+ *
+ * @NFTA_RANGE_SREG: source register of data to compare (NLA_U32: nft_registers)
+ * @NFTA_RANGE_OP: cmp operation (NLA_U32: nft_cmp_ops)
+ * @NFTA_RANGE_FROM_DATA: data range from (NLA_NESTED: nft_data_attributes)
+ * @NFTA_RANGE_TO_DATA: data range to (NLA_NESTED: nft_data_attributes)
+ */
+enum nft_range_attributes {
+ NFTA_RANGE_UNSPEC,
+ NFTA_RANGE_SREG,
+ NFTA_RANGE_OP,
+ NFTA_RANGE_FROM_DATA,
+ NFTA_RANGE_TO_DATA,
+ __NFTA_RANGE_MAX
+};
+#define NFTA_RANGE_MAX (__NFTA_RANGE_MAX - 1)
+
enum nft_lookup_flags {
NFT_LOOKUP_F_INV = (1 << 0),
};
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 0c8581100ac6..c23c3c84416f 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -71,8 +71,9 @@ obj-$(CONFIG_NF_DUP_NETDEV) += nf_dup_netdev.o
# nf_tables
nf_tables-objs += nf_tables_core.o nf_tables_api.o nf_tables_trace.o
-nf_tables-objs += nft_immediate.o nft_cmp.o nft_lookup.o nft_dynset.o
+nf_tables-objs += nft_immediate.o nft_cmp.o nft_range.o
nf_tables-objs += nft_bitwise.o nft_byteorder.o nft_payload.o
+nf_tables-objs += nft_lookup.o nft_dynset.o
obj-$(CONFIG_NF_TABLES) += nf_tables.o
obj-$(CONFIG_NF_TABLES_INET) += nf_tables_inet.o
diff --git a/net/netfilter/nf_tables_core.c b/net/netfilter/nf_tables_core.c
index 67259cefef06..7c94ce0080d5 100644
--- a/net/netfilter/nf_tables_core.c
+++ b/net/netfilter/nf_tables_core.c
@@ -263,8 +263,13 @@ int __init nf_tables_core_module_init(void)
if (err < 0)
goto err7;
- return 0;
+ err = nft_range_module_init();
+ if (err < 0)
+ goto err8;
+ return 0;
+err8:
+ nft_dynset_module_exit();
err7:
nft_payload_module_exit();
err6:
diff --git a/net/netfilter/nft_range.c b/net/netfilter/nft_range.c
new file mode 100644
index 000000000000..c6d5358482d1
--- /dev/null
+++ b/net/netfilter/nft_range.c
@@ -0,0 +1,138 @@
+/*
+ * Copyright (c) 2016 Pablo Neira Ayuso <pablo@...filter.org>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/netlink.h>
+#include <linux/netfilter.h>
+#include <linux/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+#include <net/netfilter/nf_tables.h>
+
+struct nft_range_expr {
+ struct nft_data data_from;
+ struct nft_data data_to;
+ enum nft_registers sreg:8;
+ u8 len;
+ enum nft_range_ops op:8;
+};
+
+static void nft_range_eval(const struct nft_expr *expr,
+ struct nft_regs *regs,
+ const struct nft_pktinfo *pkt)
+{
+ const struct nft_range_expr *priv = nft_expr_priv(expr);
+ bool mismatch;
+ int d1, d2;
+
+ d1 = memcmp(®s->data[priv->sreg], &priv->data_from, priv->len);
+ d2 = memcmp(®s->data[priv->sreg], &priv->data_to, priv->len);
+ switch (priv->op) {
+ case NFT_RANGE_EQ:
+ mismatch = (d1 < 0 || d2 > 0);
+ break;
+ case NFT_RANGE_NEQ:
+ mismatch = (d1 >= 0 && d2 <= 0);
+ break;
+ }
+
+ if (mismatch)
+ regs->verdict.code = NFT_BREAK;
+}
+
+static const struct nla_policy nft_range_policy[NFTA_RANGE_MAX + 1] = {
+ [NFTA_RANGE_SREG] = { .type = NLA_U32 },
+ [NFTA_RANGE_OP] = { .type = NLA_U32 },
+ [NFTA_RANGE_FROM_DATA] = { .type = NLA_NESTED },
+ [NFTA_RANGE_TO_DATA] = { .type = NLA_NESTED },
+};
+
+static int nft_range_init(const struct nft_ctx *ctx, const struct nft_expr *expr,
+ const struct nlattr * const tb[])
+{
+ struct nft_range_expr *priv = nft_expr_priv(expr);
+ struct nft_data_desc desc_from, desc_to;
+ int err;
+
+ err = nft_data_init(NULL, &priv->data_from, sizeof(priv->data_from),
+ &desc_from, tb[NFTA_RANGE_FROM_DATA]);
+ if (err < 0)
+ return err;
+
+ err = nft_data_init(NULL, &priv->data_to, sizeof(priv->data_to),
+ &desc_to, tb[NFTA_RANGE_TO_DATA]);
+ if (err < 0)
+ goto err1;
+
+ if (desc_from.len != desc_to.len) {
+ err = -EINVAL;
+ goto err2;
+ }
+
+ priv->sreg = nft_parse_register(tb[NFTA_RANGE_SREG]);
+ err = nft_validate_register_load(priv->sreg, desc_from.len);
+ if (err < 0)
+ goto err2;
+
+ priv->op = ntohl(nla_get_be32(tb[NFTA_RANGE_OP]));
+ priv->len = desc_from.len;
+ return 0;
+err2:
+ nft_data_uninit(&priv->data_to, desc_to.type);
+err1:
+ nft_data_uninit(&priv->data_from, desc_from.type);
+ return err;
+}
+
+static int nft_range_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+ const struct nft_range_expr *priv = nft_expr_priv(expr);
+
+ if (nft_dump_register(skb, NFTA_RANGE_SREG, priv->sreg))
+ goto nla_put_failure;
+ if (nla_put_be32(skb, NFTA_RANGE_OP, htonl(priv->op)))
+ goto nla_put_failure;
+
+ if (nft_data_dump(skb, NFTA_RANGE_FROM_DATA, &priv->data_from,
+ NFT_DATA_VALUE, priv->len) < 0 ||
+ nft_data_dump(skb, NFTA_RANGE_TO_DATA, &priv->data_to,
+ NFT_DATA_VALUE, priv->len) < 0)
+ goto nla_put_failure;
+ return 0;
+
+nla_put_failure:
+ return -1;
+}
+
+static struct nft_expr_type nft_range_type;
+static const struct nft_expr_ops nft_range_ops = {
+ .type = &nft_range_type,
+ .size = NFT_EXPR_SIZE(sizeof(struct nft_range_expr)),
+ .eval = nft_range_eval,
+ .init = nft_range_init,
+ .dump = nft_range_dump,
+};
+
+static struct nft_expr_type nft_range_type __read_mostly = {
+ .name = "range",
+ .ops = &nft_range_ops,
+ .policy = nft_range_policy,
+ .maxattr = NFTA_RANGE_MAX,
+ .owner = THIS_MODULE,
+};
+
+int __init nft_range_module_init(void)
+{
+ return nft_register_expr(&nft_range_type);
+}
+
+void nft_range_module_exit(void)
+{
+ nft_unregister_expr(&nft_range_type);
+}
--
2.1.4
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