[v3] netfilter: nft_numgen: add number generator expression
diff mbox

Message ID 20160813223941.GA11051@sonyv
State Changes Requested
Delegated to: Pablo Neira
Headers show

Commit Message

Laura Garcia Liebana Aug. 13, 2016, 10:39 p.m. UTC
Add support for the number generator expression in netfilter.

Signed-off-by: Laura Garcia Liebana <nevola@gmail.com>
---
Changes in V3:
	- Include random number generation
	- Rename nft_nth by nft_numgen

 include/uapi/linux/netfilter/nf_tables.h |  25 ++++
 net/netfilter/Kconfig                    |   6 +
 net/netfilter/Makefile                   |   1 +
 net/netfilter/nft_numgen.c               | 193 +++++++++++++++++++++++++++++++
 4 files changed, 225 insertions(+)
 create mode 100644 net/netfilter/nft_numgen.c

Comments

kernel test robot Aug. 14, 2016, 4:03 p.m. UTC | #1
Hi Laura,

[auto build test ERROR on nf-next/master]
[also build test ERROR on v4.8-rc1 next-20160812]
[if your patch is applied to the wrong git tree, please drop us a note to help improve the system]

url:    https://github.com/0day-ci/linux/commits/Laura-Garcia-Liebana/netfilter-nft_numgen-add-number-generator-expression/20160814-185132
base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git master
config: i386-allyesconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
        # save the attached .config to linux build tree
        make ARCH=i386 

All errors (new ones prefixed by >>):

>> net/netfilter/nft_numgen.o:(.discard+0x0): multiple definition of `__pcpu_unique_nft_prandom_state'
   net/netfilter/nft_meta.o:(.discard+0x0): first defined here

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation
Laura Garcia Liebana Aug. 17, 2016, 1:59 p.m. UTC | #2
On Mon, Aug 15, 2016 at 12:03:19AM +0800, kbuild test robot wrote:
> Hi Laura,
> 
> [auto build test ERROR on nf-next/master]
> [also build test ERROR on v4.8-rc1 next-20160812]
> [if your patch is applied to the wrong git tree, please drop us a note to help improve the system]
> 
> url:    https://github.com/0day-ci/linux/commits/Laura-Garcia-Liebana/netfilter-nft_numgen-add-number-generator-expression/20160814-185132
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/pablo/nf-next.git master
> config: i386-allyesconfig (attached as .config)
> compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
>         # save the attached .config to linux build tree
>         make ARCH=i386 
> 
> All errors (new ones prefixed by >>):
> 
> >> net/netfilter/nft_numgen.o:(.discard+0x0): multiple definition of `__pcpu_unique_nft_prandom_state'
>    net/netfilter/nft_meta.o:(.discard+0x0): first defined here
> 
> ---
> 0-DAY kernel test infrastructure                Open Source Technology Center
> https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

Hi, I've been compiling with several options like:

CONFIG_NFT_META=m
CONFIG_NFT_NUMGEN=m

and

CONFIG_NFT_META=y
CONFIG_NFT_NUMGEN=y

but I was unable to reproduce it.

Anyway, I'll rename the identifier in a new patch.

Thanks.

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Patch
diff mbox

diff --git a/include/uapi/linux/netfilter/nf_tables.h b/include/uapi/linux/netfilter/nf_tables.h
index c674ba2..38fd1ef 100644
--- a/include/uapi/linux/netfilter/nf_tables.h
+++ b/include/uapi/linux/netfilter/nf_tables.h
@@ -1082,4 +1082,29 @@  enum nft_trace_types {
 	__NFT_TRACETYPE_MAX
 };
 #define NFT_TRACETYPE_MAX (__NFT_TRACETYPE_MAX - 1)
+
+/**
+ * enum nft_ng_attributes - nf_tables number generator expression netlink
+ *			    attributes
+ *
+ * @NFTA_NG_DREG: destination register (NLA_U32)
+ * @NFTA_NG_UNTIL: source value to increment the counter until reset (NLA_U32)
+ * @NFTA_NG_TYPE: operation type (NLA_U32)
+ */
+enum nft_ng_attributes {
+	NFTA_NG_UNSPEC,
+	NFTA_NG_DREG,
+	NFTA_NG_UNTIL,
+	NFTA_NG_TYPE,
+	__NFTA_NG_MAX
+};
+#define NFTA_NG_MAX	(__NFTA_NG_MAX - 1)
+
+enum nft_ng_types {
+	NFT_NG_INCREMENTAL,
+	NFT_NG_RANDOM,
+	__NFT_NG_MAX
+};
+#define NFT_NG_MAX	(__NFT_NG_MAX - 1)
+
 #endif /* _LINUX_NF_TABLES_H */
diff --git a/net/netfilter/Kconfig b/net/netfilter/Kconfig
index 9266cee..31def7d 100644
--- a/net/netfilter/Kconfig
+++ b/net/netfilter/Kconfig
@@ -474,6 +474,12 @@  config NFT_META
 	  This option adds the "meta" expression that you can use to match and
 	  to set packet metainformation such as the packet mark.
 
+config NFT_NUMGEN
+	tristate "Netfilter nf_tables number generator module"
+	help
+	  This option adds the number generator expression used to perform
+	  operations like the incremental counter until a reset value or random.
+
 config NFT_CT
 	depends on NF_CONNTRACK
 	tristate "Netfilter nf_tables conntrack module"
diff --git a/net/netfilter/Makefile b/net/netfilter/Makefile
index 6913454..81f22c3 100644
--- a/net/netfilter/Makefile
+++ b/net/netfilter/Makefile
@@ -80,6 +80,7 @@  obj-$(CONFIG_NF_TABLES_NETDEV)	+= nf_tables_netdev.o
 obj-$(CONFIG_NFT_COMPAT)	+= nft_compat.o
 obj-$(CONFIG_NFT_EXTHDR)	+= nft_exthdr.o
 obj-$(CONFIG_NFT_META)		+= nft_meta.o
+obj-$(CONFIG_NFT_NUMGEN)	+= nft_numgen.o
 obj-$(CONFIG_NFT_CT)		+= nft_ct.o
 obj-$(CONFIG_NFT_LIMIT)		+= nft_limit.o
 obj-$(CONFIG_NFT_NAT)		+= nft_nat.o
diff --git a/net/netfilter/nft_numgen.c b/net/netfilter/nft_numgen.c
new file mode 100644
index 0000000..d6bceab
--- /dev/null
+++ b/net/netfilter/nft_numgen.c
@@ -0,0 +1,193 @@ 
+/*
+ * Copyright (c) 2016 Laura Garcia <nevola@gmail.com>
+ *
+ * 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 <linux/static_key.h>
+#include <net/netfilter/nf_tables.h>
+#include <net/netfilter/nf_tables_core.h>
+
+static DEFINE_PER_CPU(struct rnd_state, nft_prandom_state);
+
+struct nft_ng_inc {
+	enum nft_registers      dreg:8;
+	u32			until;
+	atomic_t		counter;
+};
+
+struct nft_ng_random {
+	enum nft_registers      dreg:8;
+	u32			until;
+};
+
+static void nft_ng_inc_eval(const struct nft_expr *expr,
+			    struct nft_regs *regs,
+			    const struct nft_pktinfo *pkt)
+{
+	struct nft_ng_inc *priv = nft_expr_priv(expr);
+	u32 nval, oval;
+
+	do {
+		oval = atomic_read(&priv->counter);
+		nval = (oval + 1 < priv->until) ? oval + 1 : 0;
+	} while (atomic_cmpxchg(&priv->counter, oval, nval) != oval);
+
+	memcpy(&regs->data[priv->dreg], &priv->counter, sizeof(u32));
+}
+
+static void nft_ng_random_eval(const struct nft_expr *expr,
+			       struct nft_regs *regs,
+			       const struct nft_pktinfo *pkt)
+{
+	struct nft_ng_random *priv = nft_expr_priv(expr);
+	struct rnd_state *state = this_cpu_ptr(&nft_prandom_state);
+	u32 p;
+
+	p = reciprocal_scale(prandom_u32_state(state), priv->until);
+
+	regs->data[priv->dreg] = p;
+}
+
+const struct nla_policy nft_ng_policy[NFTA_NG_MAX + 1] = {
+	[NFTA_NG_DREG]		= { .type = NLA_U32 },
+	[NFTA_NG_UNTIL]		= { .type = NLA_U32 },
+	[NFTA_NG_TYPE]		= { .type = NLA_U32 },
+};
+
+static int nft_ng_inc_init(const struct nft_ctx *ctx,
+			   const struct nft_expr *expr,
+			   const struct nlattr * const tb[])
+{
+	struct nft_ng_inc *priv = nft_expr_priv(expr);
+
+	priv->until = ntohl(nla_get_be32(tb[NFTA_NG_UNTIL]));
+	if (priv->until == 0)
+		return -EINVAL;
+
+	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
+	atomic_set(&priv->counter, 0);
+
+	return nft_validate_register_store(ctx, priv->dreg, NULL,
+					   NFT_DATA_VALUE, sizeof(u32));
+}
+
+static int nft_ng_random_init(const struct nft_ctx *ctx,
+			      const struct nft_expr *expr,
+			      const struct nlattr * const tb[])
+{
+	struct nft_ng_random *priv = nft_expr_priv(expr);
+	u32 len;
+
+	priv->until = ntohl(nla_get_be32(tb[NFTA_NG_UNTIL]));
+
+	prandom_init_once(&nft_prandom_state);
+	len = sizeof(u32);
+
+	priv->dreg = nft_parse_register(tb[NFTA_NG_DREG]);
+
+	return nft_validate_register_store(ctx, priv->dreg, NULL,
+					   NFT_DATA_VALUE, len);
+}
+
+static int nft_ng_dump(struct sk_buff *skb, enum nft_registers dreg,
+		       u32 until, enum nft_ng_types type)
+{
+	if (nft_dump_register(skb, NFTA_NG_DREG, dreg))
+		goto nla_put_failure;
+	if (nft_dump_register(skb, NFTA_NG_UNTIL, until))
+		goto nla_put_failure;
+	if (nft_dump_register(skb, NFTA_NG_TYPE, type))
+		goto nla_put_failure;
+
+	return 0;
+
+nla_put_failure:
+	return -1;
+}
+
+static int nft_ng_inc_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_ng_inc *priv = nft_expr_priv(expr);
+
+	return nft_ng_dump(skb, priv->dreg, priv->until, NFT_NG_INCREMENTAL);
+}
+
+static int nft_ng_random_dump(struct sk_buff *skb, const struct nft_expr *expr)
+{
+	const struct nft_ng_random *priv = nft_expr_priv(expr);
+
+	return nft_ng_dump(skb, priv->dreg, priv->until, NFT_NG_RANDOM);
+}
+
+static struct nft_expr_type nft_ng_type;
+static const struct nft_expr_ops nft_ng_inc_ops = {
+	.type		= &nft_ng_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_inc)),
+	.eval		= nft_ng_inc_eval,
+	.init		= nft_ng_inc_init,
+	.dump		= nft_ng_inc_dump,
+};
+
+static const struct nft_expr_ops nft_ng_random_ops = {
+	.type		= &nft_ng_type,
+	.size		= NFT_EXPR_SIZE(sizeof(struct nft_ng_random)),
+	.eval		= nft_ng_random_eval,
+	.init		= nft_ng_random_init,
+	.dump		= nft_ng_random_dump,
+};
+
+static const struct nft_expr_ops *
+nft_ng_select_ops(const struct nft_ctx *ctx, const struct nlattr * const tb[])
+{
+	u32 type;
+
+	if (!tb[NFTA_NG_DREG]	||
+	    !tb[NFTA_NG_UNTIL]	||
+	    !tb[NFTA_NG_TYPE])
+		return ERR_PTR(-EINVAL);
+
+	type = ntohl(nla_get_be32(tb[NFTA_NG_TYPE]));
+
+	if (type == NFT_NG_INCREMENTAL)
+		return &nft_ng_inc_ops;
+
+	if (type == NFT_NG_RANDOM)
+		return &nft_ng_random_ops;
+
+	return ERR_PTR(-EINVAL);
+}
+
+static struct nft_expr_type nft_ng_type __read_mostly = {
+	.name		= "numgen",
+	.select_ops	= &nft_ng_select_ops,
+	.policy		= nft_ng_policy,
+	.maxattr	= NFTA_NG_MAX,
+	.owner		= THIS_MODULE,
+};
+
+static int __init nft_ng_module_init(void)
+{
+	return nft_register_expr(&nft_ng_type);
+}
+
+static void __exit nft_ng_module_exit(void)
+{
+	nft_unregister_expr(&nft_ng_type);
+}
+
+module_init(nft_ng_module_init);
+module_exit(nft_ng_module_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Laura Garcia <nevola@gmail.com>");
+MODULE_ALIAS_NFT_EXPR("numgen");