diff mbox series

[bpf-next,v1,07/10] bpfilter: Add struct rule

Message ID 20210603101425.560384-8-me@ubique.spb.ru (mailing list archive)
State Changes Requested
Delegated to: BPF
Headers show
Series bpfilter | expand

Checks

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netdev/cc_maintainers warning 5 maintainers not CCed: linux-kselftest@vger.kernel.org masahiroy@kernel.org yuehaibing@huawei.com shuah@kernel.org kuba@kernel.org
netdev/source_inline success Was 0 now: 0
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netdev/build_32bit success Errors and warnings before: 0 this patch: 0
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netdev/verify_fixes success Link
netdev/checkpatch warning CHECK: Prefer kernel type 'u16' over 'uint16_t' CHECK: Prefer kernel type 'u32' over 'uint32_t' WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 100 exceeds 80 columns WARNING: line length of 82 exceeds 80 columns WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns WARNING: line length of 90 exceeds 80 columns WARNING: line length of 93 exceeds 80 columns WARNING: line length of 95 exceeds 80 columns WARNING: line length of 97 exceeds 80 columns WARNING: line length of 98 exceeds 80 columns
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success Link

Commit Message

Dmitrii Banshchikov June 3, 2021, 10:14 a.m. UTC
struct rule is an equivalent of struct ipt_entry. A rule consists of
zero or more matches and a target. A rule has a pointer to its ipt_entry
in entries blob.  struct rule should simplify iteration over a blob and
avoid blob's guts in code generation.

Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
---
 net/bpfilter/Makefile                         |   2 +-
 net/bpfilter/rule.c                           | 163 ++++++++++++++++++
 net/bpfilter/rule.h                           |  32 ++++
 .../testing/selftests/bpf/bpfilter/.gitignore |   1 +
 tools/testing/selftests/bpf/bpfilter/Makefile |   5 +-
 .../selftests/bpf/bpfilter/bpfilter_util.h    |   8 +
 .../selftests/bpf/bpfilter/test_rule.c        |  55 ++++++
 7 files changed, 264 insertions(+), 2 deletions(-)
 create mode 100644 net/bpfilter/rule.c
 create mode 100644 net/bpfilter/rule.h
 create mode 100644 tools/testing/selftests/bpf/bpfilter/test_rule.c

Comments

Yonghong Song June 10, 2021, 12:30 a.m. UTC | #1
On 6/3/21 3:14 AM, Dmitrii Banshchikov wrote:
> struct rule is an equivalent of struct ipt_entry. A rule consists of
> zero or more matches and a target. A rule has a pointer to its ipt_entry
> in entries blob.  struct rule should simplify iteration over a blob and
> avoid blob's guts in code generation.
> 
> Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
> ---
>   net/bpfilter/Makefile                         |   2 +-
>   net/bpfilter/rule.c                           | 163 ++++++++++++++++++
>   net/bpfilter/rule.h                           |  32 ++++
>   .../testing/selftests/bpf/bpfilter/.gitignore |   1 +
>   tools/testing/selftests/bpf/bpfilter/Makefile |   5 +-
>   .../selftests/bpf/bpfilter/bpfilter_util.h    |   8 +
>   .../selftests/bpf/bpfilter/test_rule.c        |  55 ++++++
>   7 files changed, 264 insertions(+), 2 deletions(-)
>   create mode 100644 net/bpfilter/rule.c
>   create mode 100644 net/bpfilter/rule.h
>   create mode 100644 tools/testing/selftests/bpf/bpfilter/test_rule.c
> 
[...]
> +
> +bool rule_has_standard_target(const struct rule *rule);
> +bool is_rule_unconditional(const struct rule *rule);
> +int init_rule(struct context *ctx, const struct bpfilter_ipt_entry *ipt_entry, struct rule *rule);
> +void free_rule(struct rule *rule);
> +
> +#endif // NET_BPFILTER_RULE_H
> diff --git a/tools/testing/selftests/bpf/bpfilter/.gitignore b/tools/testing/selftests/bpf/bpfilter/.gitignore
> index 7e077f506af1..4d7c5083d980 100644
> --- a/tools/testing/selftests/bpf/bpfilter/.gitignore
> +++ b/tools/testing/selftests/bpf/bpfilter/.gitignore
> @@ -2,3 +2,4 @@
>   test_map
>   test_match
>   test_target
> +test_rule
> diff --git a/tools/testing/selftests/bpf/bpfilter/Makefile b/tools/testing/selftests/bpf/bpfilter/Makefile
> index a11775e8b5af..27a1ddcb6dc9 100644
> --- a/tools/testing/selftests/bpf/bpfilter/Makefile
> +++ b/tools/testing/selftests/bpf/bpfilter/Makefile
> @@ -11,6 +11,7 @@ CFLAGS += -Wall -g -pthread -I$(TOOLSINCDIR) -I$(APIDIR) -I$(BPFILTERSRCDIR)
>   TEST_GEN_PROGS += test_map
>   TEST_GEN_PROGS += test_match
>   TEST_GEN_PROGS += test_target
> +TEST_GEN_PROGS += test_rule
>   
>   KSFT_KHDR_INSTALL := 1
>   
> @@ -19,9 +20,11 @@ include ../../lib.mk
>   BPFILTER_MATCH_SRCS := $(BPFILTERSRCDIR)/match.c $(BPFILTERSRCDIR)/xt_udp.c
>   BPFILTER_TARGET_SRCS := $(BPFILTERSRCDIR)/target.c
>   
> -BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c
> +BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c \
> +	$(BPFILTERSRCDIR)/rule.c
>   BPFILTER_COMMON_SRCS += $(BPFILTER_MATCH_SRCS) $(BPFILTER_TARGET_SRCS)
>   
>   $(OUTPUT)/test_map: test_map.c $(BPFILTERSRCDIR)/map-common.c
>   $(OUTPUT)/test_match: test_match.c $(BPFILTER_COMMON_SRCS)
>   $(OUTPUT)/test_target: test_target.c $(BPFILTER_COMMON_SRCS)
> +$(OUTPUT)/test_rule: test_rule.c $(BPFILTER_COMMON_SRCS)
> diff --git a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> index d82ff86f280e..55fb0e959fca 100644
> --- a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> +++ b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> @@ -7,6 +7,7 @@
>   #include <linux/netfilter/x_tables.h>
>   
>   #include <stdio.h>
> +#include <string.h>
>   
>   static inline void init_standard_target(struct xt_standard_target *ipt_target, int revision,
>   					int verdict)
> @@ -28,4 +29,11 @@ static inline void init_error_target(struct xt_error_target *ipt_target, int rev
>   	snprintf(ipt_target->errorname, sizeof(ipt_target->errorname), "%s", error_name);
>   }
>   
> +static inline void init_standard_entry(struct ipt_entry *entry, __u16 matches_size)
> +{
> +	memset(entry, 0, sizeof(*entry));
> +	entry->target_offset = sizeof(*entry) + matches_size;
> +	entry->next_offset = sizeof(*entry) + matches_size + sizeof(struct xt_standard_target);
> +}
> +
>   #endif // BPFILTER_UTIL_H
> diff --git a/tools/testing/selftests/bpf/bpfilter/test_rule.c b/tools/testing/selftests/bpf/bpfilter/test_rule.c
> new file mode 100644
> index 000000000000..fe12adf32fe5
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/bpfilter/test_rule.c
> @@ -0,0 +1,55 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +#define _GNU_SOURCE
> +
> +#include "rule.h"
> +
> +#include <linux/bpfilter.h>
> +#include <linux/err.h>
> +
> +#include <linux/netfilter_ipv4/ip_tables.h>
> +
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +#include "../../kselftest_harness.h"
> +
> +#include "context.h"
> +#include "rule.h"
> +
> +#include "bpfilter_util.h"
> +
> +FIXTURE(test_standard_rule)
> +{
> +	struct context ctx;
> +	struct {
> +		struct ipt_entry entry;
> +		struct xt_standard_target target;
> +	} entry;
> +	struct rule rule;
> +};
> +
> +FIXTURE_SETUP(test_standard_rule)
> +{
> +	const int verdict = BPFILTER_NF_ACCEPT;
> +
> +	ASSERT_EQ(create_context(&self->ctx), 0);
> +	self->ctx.log_file = stderr;
> +
> +	init_standard_entry(&self->entry.entry, 0);
> +	init_standard_target(&self->entry.target, 0, -verdict - 1);
> +}
> +
> +FIXTURE_TEARDOWN(test_standard_rule)
> +{
> +	free_rule(&self->rule);
> +	free_context(&self->ctx);
> +}
> +
> +TEST_F(test_standard_rule, init)
> +{
> +	ASSERT_EQ(0, init_rule(&self->ctx, (const struct bpfilter_ipt_entry *)&self->entry.entry,
> +			       &self->rule));
> +}
> +
> +TEST_HARNESS_MAIN

When compiling selftests/bpf/bpfilter, I got the following compilation 
warning:

gcc -Wall -g -pthread -I/home/yhs/work/bpf-next/tools/include 
-I/home/yhs/work/bpf-next/tools/include/uapi 
-I../../../../../net/bpfilter    test_rule.c 
../../../../../net/bpfilter/map-common.c 
../../../../../net/bpfilter/context.c ../../../../../net/bpfilter/rule.c 
../../../../../net/bpfilter/table.c ../../../../../net/bpfilter/match.c 
../../../../../net/bpfilter/xt_udp.c 
../../../../../net/bpfilter/target.c  -o 
/home/yhs/work/bpf-next/tools/testing/selftests/bpf/bpfilter/test_rule
In file included from test_rule.c:15:
../../kselftest_harness.h:674: warning: "ARRAY_SIZE" redefined
  #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))

In file included from /usr/include/linux/netfilter/x_tables.h:4,
                  from /usr/include/linux/netfilter_ipv4/ip_tables.h:24,
                  from test_rule.c:10:
/home/yhs/work/bpf-next/tools/include/linux/kernel.h:105: note: this is 
the location of the previous definition
  #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) + 
__must_be_array(arr))
Dmitrii Banshchikov June 10, 2021, 1:16 p.m. UTC | #2
On Wed, Jun 09, 2021 at 05:30:56PM -0700, Yonghong Song wrote:
> 
> 
> On 6/3/21 3:14 AM, Dmitrii Banshchikov wrote:
> > struct rule is an equivalent of struct ipt_entry. A rule consists of
> > zero or more matches and a target. A rule has a pointer to its ipt_entry
> > in entries blob.  struct rule should simplify iteration over a blob and
> > avoid blob's guts in code generation.
> > 
> > Signed-off-by: Dmitrii Banshchikov <me@ubique.spb.ru>
> > ---
> >   net/bpfilter/Makefile                         |   2 +-
> >   net/bpfilter/rule.c                           | 163 ++++++++++++++++++
> >   net/bpfilter/rule.h                           |  32 ++++
> >   .../testing/selftests/bpf/bpfilter/.gitignore |   1 +
> >   tools/testing/selftests/bpf/bpfilter/Makefile |   5 +-
> >   .../selftests/bpf/bpfilter/bpfilter_util.h    |   8 +
> >   .../selftests/bpf/bpfilter/test_rule.c        |  55 ++++++
> >   7 files changed, 264 insertions(+), 2 deletions(-)
> >   create mode 100644 net/bpfilter/rule.c
> >   create mode 100644 net/bpfilter/rule.h
> >   create mode 100644 tools/testing/selftests/bpf/bpfilter/test_rule.c
> > 
> [...]
> > +
> > +bool rule_has_standard_target(const struct rule *rule);
> > +bool is_rule_unconditional(const struct rule *rule);
> > +int init_rule(struct context *ctx, const struct bpfilter_ipt_entry *ipt_entry, struct rule *rule);
> > +void free_rule(struct rule *rule);
> > +
> > +#endif // NET_BPFILTER_RULE_H
> > diff --git a/tools/testing/selftests/bpf/bpfilter/.gitignore b/tools/testing/selftests/bpf/bpfilter/.gitignore
> > index 7e077f506af1..4d7c5083d980 100644
> > --- a/tools/testing/selftests/bpf/bpfilter/.gitignore
> > +++ b/tools/testing/selftests/bpf/bpfilter/.gitignore
> > @@ -2,3 +2,4 @@
> >   test_map
> >   test_match
> >   test_target
> > +test_rule
> > diff --git a/tools/testing/selftests/bpf/bpfilter/Makefile b/tools/testing/selftests/bpf/bpfilter/Makefile
> > index a11775e8b5af..27a1ddcb6dc9 100644
> > --- a/tools/testing/selftests/bpf/bpfilter/Makefile
> > +++ b/tools/testing/selftests/bpf/bpfilter/Makefile
> > @@ -11,6 +11,7 @@ CFLAGS += -Wall -g -pthread -I$(TOOLSINCDIR) -I$(APIDIR) -I$(BPFILTERSRCDIR)
> >   TEST_GEN_PROGS += test_map
> >   TEST_GEN_PROGS += test_match
> >   TEST_GEN_PROGS += test_target
> > +TEST_GEN_PROGS += test_rule
> >   KSFT_KHDR_INSTALL := 1
> > @@ -19,9 +20,11 @@ include ../../lib.mk
> >   BPFILTER_MATCH_SRCS := $(BPFILTERSRCDIR)/match.c $(BPFILTERSRCDIR)/xt_udp.c
> >   BPFILTER_TARGET_SRCS := $(BPFILTERSRCDIR)/target.c
> > -BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c
> > +BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c \
> > +	$(BPFILTERSRCDIR)/rule.c
> >   BPFILTER_COMMON_SRCS += $(BPFILTER_MATCH_SRCS) $(BPFILTER_TARGET_SRCS)
> >   $(OUTPUT)/test_map: test_map.c $(BPFILTERSRCDIR)/map-common.c
> >   $(OUTPUT)/test_match: test_match.c $(BPFILTER_COMMON_SRCS)
> >   $(OUTPUT)/test_target: test_target.c $(BPFILTER_COMMON_SRCS)
> > +$(OUTPUT)/test_rule: test_rule.c $(BPFILTER_COMMON_SRCS)
> > diff --git a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> > index d82ff86f280e..55fb0e959fca 100644
> > --- a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> > +++ b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
> > @@ -7,6 +7,7 @@
> >   #include <linux/netfilter/x_tables.h>
> >   #include <stdio.h>
> > +#include <string.h>
> >   static inline void init_standard_target(struct xt_standard_target *ipt_target, int revision,
> >   					int verdict)
> > @@ -28,4 +29,11 @@ static inline void init_error_target(struct xt_error_target *ipt_target, int rev
> >   	snprintf(ipt_target->errorname, sizeof(ipt_target->errorname), "%s", error_name);
> >   }
> > +static inline void init_standard_entry(struct ipt_entry *entry, __u16 matches_size)
> > +{
> > +	memset(entry, 0, sizeof(*entry));
> > +	entry->target_offset = sizeof(*entry) + matches_size;
> > +	entry->next_offset = sizeof(*entry) + matches_size + sizeof(struct xt_standard_target);
> > +}
> > +
> >   #endif // BPFILTER_UTIL_H
> > diff --git a/tools/testing/selftests/bpf/bpfilter/test_rule.c b/tools/testing/selftests/bpf/bpfilter/test_rule.c
> > new file mode 100644
> > index 000000000000..fe12adf32fe5
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/bpfilter/test_rule.c
> > @@ -0,0 +1,55 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +
> > +#define _GNU_SOURCE
> > +
> > +#include "rule.h"
> > +
> > +#include <linux/bpfilter.h>
> > +#include <linux/err.h>
> > +
> > +#include <linux/netfilter_ipv4/ip_tables.h>
> > +
> > +#include <stdio.h>
> > +#include <stdlib.h>
> > +
> > +#include "../../kselftest_harness.h"
> > +
> > +#include "context.h"
> > +#include "rule.h"
> > +
> > +#include "bpfilter_util.h"
> > +
> > +FIXTURE(test_standard_rule)
> > +{
> > +	struct context ctx;
> > +	struct {
> > +		struct ipt_entry entry;
> > +		struct xt_standard_target target;
> > +	} entry;
> > +	struct rule rule;
> > +};
> > +
> > +FIXTURE_SETUP(test_standard_rule)
> > +{
> > +	const int verdict = BPFILTER_NF_ACCEPT;
> > +
> > +	ASSERT_EQ(create_context(&self->ctx), 0);
> > +	self->ctx.log_file = stderr;
> > +
> > +	init_standard_entry(&self->entry.entry, 0);
> > +	init_standard_target(&self->entry.target, 0, -verdict - 1);
> > +}
> > +
> > +FIXTURE_TEARDOWN(test_standard_rule)
> > +{
> > +	free_rule(&self->rule);
> > +	free_context(&self->ctx);
> > +}
> > +
> > +TEST_F(test_standard_rule, init)
> > +{
> > +	ASSERT_EQ(0, init_rule(&self->ctx, (const struct bpfilter_ipt_entry *)&self->entry.entry,
> > +			       &self->rule));
> > +}
> > +
> > +TEST_HARNESS_MAIN
> 
> When compiling selftests/bpf/bpfilter, I got the following compilation
> warning:
> 
> gcc -Wall -g -pthread -I/home/yhs/work/bpf-next/tools/include
> -I/home/yhs/work/bpf-next/tools/include/uapi -I../../../../../net/bpfilter
> test_rule.c ../../../../../net/bpfilter/map-common.c
> ../../../../../net/bpfilter/context.c ../../../../../net/bpfilter/rule.c
> ../../../../../net/bpfilter/table.c ../../../../../net/bpfilter/match.c
> ../../../../../net/bpfilter/xt_udp.c ../../../../../net/bpfilter/target.c
> -o /home/yhs/work/bpf-next/tools/testing/selftests/bpf/bpfilter/test_rule
> In file included from test_rule.c:15:
> ../../kselftest_harness.h:674: warning: "ARRAY_SIZE" redefined
>  #define ARRAY_SIZE(a) (sizeof(a) / sizeof(a[0]))
> 
> In file included from /usr/include/linux/netfilter/x_tables.h:4,
>                  from /usr/include/linux/netfilter_ipv4/ip_tables.h:24,
>                  from test_rule.c:10:
> /home/yhs/work/bpf-next/tools/include/linux/kernel.h:105: note: this is the
> location of the previous definition
>  #define ARRAY_SIZE(arr) (sizeof(arr) / sizeof((arr)[0]) +
> __must_be_array(arr))
> 

Hmm. I cannot reproduce it locally now though I saw this error and
fixed it by removing some of the includes from header files.
I will double check it.
diff mbox series

Patch

diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index 031c9dd40d2d..7ce961162283 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -4,7 +4,7 @@ 
 #
 
 userprogs := bpfilter_umh
-bpfilter_umh-objs := main.o map-common.o context.o match.o target.o
+bpfilter_umh-objs := main.o map-common.o context.o match.o target.o rule.o
 bpfilter_umh-objs += xt_udp.o
 userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
 
diff --git a/net/bpfilter/rule.c b/net/bpfilter/rule.c
new file mode 100644
index 000000000000..6018b4b7c0cc
--- /dev/null
+++ b/net/bpfilter/rule.c
@@ -0,0 +1,163 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#define _GNU_SOURCE
+
+#include "rule.h"
+
+#include "../../include/uapi/linux/bpfilter.h"
+
+#include <linux/err.h>
+#include <linux/netfilter/x_tables.h>
+
+#include <errno.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "context.h"
+#include "match.h"
+
+static const struct bpfilter_ipt_target *
+ipt_entry_target(const struct bpfilter_ipt_entry *ipt_entry)
+{
+	return (const void *)ipt_entry + ipt_entry->target_offset;
+}
+
+static const struct bpfilter_ipt_match *ipt_entry_match(const struct bpfilter_ipt_entry *entry,
+							size_t offset)
+{
+	return (const void *)entry + offset;
+}
+
+static int ipt_entry_num_matches(const struct bpfilter_ipt_entry *ipt_entry)
+{
+	const struct bpfilter_ipt_match *ipt_match;
+	uint32_t offset = sizeof(*ipt_entry);
+	int num_matches = 0;
+
+	while (offset < ipt_entry->target_offset) {
+		ipt_match = ipt_entry_match(ipt_entry, offset);
+
+		if ((uintptr_t)ipt_match % __alignof__(struct bpfilter_ipt_match))
+			return -EINVAL;
+
+		if (ipt_entry->target_offset < offset + sizeof(*ipt_match))
+			return -EINVAL;
+
+		if (ipt_match->u.match_size < sizeof(*ipt_match))
+			return -EINVAL;
+
+		if (ipt_entry->target_offset < offset + ipt_match->u.match_size)
+			return -EINVAL;
+
+		++num_matches;
+		offset += ipt_match->u.match_size;
+	}
+
+	if (offset != ipt_entry->target_offset)
+		return -EINVAL;
+
+	return num_matches;
+}
+
+static int init_rule_matches(struct context *ctx, const struct bpfilter_ipt_entry *ipt_entry,
+			     struct rule *rule)
+{
+	const struct bpfilter_ipt_match *ipt_match;
+	uint32_t offset = sizeof(*ipt_entry);
+	struct match *match;
+	int err;
+
+	rule->matches = calloc(rule->num_matches, sizeof(rule->matches[0]));
+	if (!rule->matches)
+		return -ENOMEM;
+
+	match = rule->matches;
+	while (offset < ipt_entry->target_offset) {
+		ipt_match = ipt_entry_match(ipt_entry, offset);
+		err = init_match(ctx, ipt_match, match);
+		if (err) {
+			free(rule->matches);
+			rule->matches = NULL;
+			return err;
+		}
+
+		++match;
+		offset += ipt_match->u.match_size;
+	}
+
+	return 0;
+}
+
+static int check_ipt_entry_ip(const struct bpfilter_ipt_ip *ip)
+{
+	if (ip->flags & ~BPFILTER_IPT_F_MASK)
+		return -EINVAL;
+
+	if (ip->invflags & ~BPFILTER_IPT_INV_MASK)
+		return -EINVAL;
+
+	return 0;
+}
+
+bool rule_has_standard_target(const struct rule *rule)
+{
+	return rule->target.target_ops == &standard_target_ops;
+}
+
+bool is_rule_unconditional(const struct rule *rule)
+{
+	static const struct bpfilter_ipt_ip unconditional;
+
+	if (rule->num_matches)
+		return false;
+
+	return !memcmp(&rule->ipt_entry->ip, &unconditional, sizeof(unconditional));
+}
+
+int init_rule(struct context *ctx, const struct bpfilter_ipt_entry *ipt_entry, struct rule *rule)
+{
+	const struct bpfilter_ipt_target *ipt_target;
+	int err;
+
+	err = check_ipt_entry_ip(&ipt_entry->ip);
+	if (err)
+		return err;
+
+	if (ipt_entry->target_offset < sizeof(*ipt_entry))
+		return -EINVAL;
+
+	if (ipt_entry->next_offset < ipt_entry->target_offset + sizeof(*ipt_target))
+		return -EINVAL;
+
+	ipt_target = ipt_entry_target(ipt_entry);
+
+	if (ipt_target->u.target_size < sizeof(*ipt_target))
+		return -EINVAL;
+
+	if (ipt_entry->next_offset < ipt_entry->target_offset + ipt_target->u.target_size)
+		return -EINVAL;
+
+	err = init_target(ctx, ipt_target, &rule->target);
+	if (err)
+		return err;
+
+	if (rule_has_standard_target(rule)) {
+		if (XT_ALIGN(ipt_entry->target_offset +
+			     sizeof(struct bpfilter_ipt_standard_target)) != ipt_entry->next_offset)
+			return -EINVAL;
+	}
+
+	rule->num_matches = ipt_entry_num_matches(ipt_entry);
+	if (rule->num_matches < 0)
+		return rule->num_matches;
+
+	return init_rule_matches(ctx, ipt_entry, rule);
+}
+
+void free_rule(struct rule *rule)
+{
+	free(rule->matches);
+}
diff --git a/net/bpfilter/rule.h b/net/bpfilter/rule.h
new file mode 100644
index 000000000000..cf879a19c670
--- /dev/null
+++ b/net/bpfilter/rule.h
@@ -0,0 +1,32 @@ 
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#ifndef NET_BPFILTER_RULE_H
+#define NET_BPFILTER_RULE_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+#include "target.h"
+
+struct bpfilter_ipt_entry;
+struct context;
+struct match;
+
+struct rule {
+	const struct bpfilter_ipt_entry *ipt_entry;
+	uint32_t came_from;
+	uint32_t hook_mask;
+	uint16_t num_matches;
+	struct match *matches;
+	struct target target;
+};
+
+bool rule_has_standard_target(const struct rule *rule);
+bool is_rule_unconditional(const struct rule *rule);
+int init_rule(struct context *ctx, const struct bpfilter_ipt_entry *ipt_entry, struct rule *rule);
+void free_rule(struct rule *rule);
+
+#endif // NET_BPFILTER_RULE_H
diff --git a/tools/testing/selftests/bpf/bpfilter/.gitignore b/tools/testing/selftests/bpf/bpfilter/.gitignore
index 7e077f506af1..4d7c5083d980 100644
--- a/tools/testing/selftests/bpf/bpfilter/.gitignore
+++ b/tools/testing/selftests/bpf/bpfilter/.gitignore
@@ -2,3 +2,4 @@ 
 test_map
 test_match
 test_target
+test_rule
diff --git a/tools/testing/selftests/bpf/bpfilter/Makefile b/tools/testing/selftests/bpf/bpfilter/Makefile
index a11775e8b5af..27a1ddcb6dc9 100644
--- a/tools/testing/selftests/bpf/bpfilter/Makefile
+++ b/tools/testing/selftests/bpf/bpfilter/Makefile
@@ -11,6 +11,7 @@  CFLAGS += -Wall -g -pthread -I$(TOOLSINCDIR) -I$(APIDIR) -I$(BPFILTERSRCDIR)
 TEST_GEN_PROGS += test_map
 TEST_GEN_PROGS += test_match
 TEST_GEN_PROGS += test_target
+TEST_GEN_PROGS += test_rule
 
 KSFT_KHDR_INSTALL := 1
 
@@ -19,9 +20,11 @@  include ../../lib.mk
 BPFILTER_MATCH_SRCS := $(BPFILTERSRCDIR)/match.c $(BPFILTERSRCDIR)/xt_udp.c
 BPFILTER_TARGET_SRCS := $(BPFILTERSRCDIR)/target.c
 
-BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c
+BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c \
+	$(BPFILTERSRCDIR)/rule.c
 BPFILTER_COMMON_SRCS += $(BPFILTER_MATCH_SRCS) $(BPFILTER_TARGET_SRCS)
 
 $(OUTPUT)/test_map: test_map.c $(BPFILTERSRCDIR)/map-common.c
 $(OUTPUT)/test_match: test_match.c $(BPFILTER_COMMON_SRCS)
 $(OUTPUT)/test_target: test_target.c $(BPFILTER_COMMON_SRCS)
+$(OUTPUT)/test_rule: test_rule.c $(BPFILTER_COMMON_SRCS)
diff --git a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
index d82ff86f280e..55fb0e959fca 100644
--- a/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
+++ b/tools/testing/selftests/bpf/bpfilter/bpfilter_util.h
@@ -7,6 +7,7 @@ 
 #include <linux/netfilter/x_tables.h>
 
 #include <stdio.h>
+#include <string.h>
 
 static inline void init_standard_target(struct xt_standard_target *ipt_target, int revision,
 					int verdict)
@@ -28,4 +29,11 @@  static inline void init_error_target(struct xt_error_target *ipt_target, int rev
 	snprintf(ipt_target->errorname, sizeof(ipt_target->errorname), "%s", error_name);
 }
 
+static inline void init_standard_entry(struct ipt_entry *entry, __u16 matches_size)
+{
+	memset(entry, 0, sizeof(*entry));
+	entry->target_offset = sizeof(*entry) + matches_size;
+	entry->next_offset = sizeof(*entry) + matches_size + sizeof(struct xt_standard_target);
+}
+
 #endif // BPFILTER_UTIL_H
diff --git a/tools/testing/selftests/bpf/bpfilter/test_rule.c b/tools/testing/selftests/bpf/bpfilter/test_rule.c
new file mode 100644
index 000000000000..fe12adf32fe5
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpfilter/test_rule.c
@@ -0,0 +1,55 @@ 
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include "rule.h"
+
+#include <linux/bpfilter.h>
+#include <linux/err.h>
+
+#include <linux/netfilter_ipv4/ip_tables.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "../../kselftest_harness.h"
+
+#include "context.h"
+#include "rule.h"
+
+#include "bpfilter_util.h"
+
+FIXTURE(test_standard_rule)
+{
+	struct context ctx;
+	struct {
+		struct ipt_entry entry;
+		struct xt_standard_target target;
+	} entry;
+	struct rule rule;
+};
+
+FIXTURE_SETUP(test_standard_rule)
+{
+	const int verdict = BPFILTER_NF_ACCEPT;
+
+	ASSERT_EQ(create_context(&self->ctx), 0);
+	self->ctx.log_file = stderr;
+
+	init_standard_entry(&self->entry.entry, 0);
+	init_standard_target(&self->entry.target, 0, -verdict - 1);
+}
+
+FIXTURE_TEARDOWN(test_standard_rule)
+{
+	free_rule(&self->rule);
+	free_context(&self->ctx);
+}
+
+TEST_F(test_standard_rule, init)
+{
+	ASSERT_EQ(0, init_rule(&self->ctx, (const struct bpfilter_ipt_entry *)&self->entry.entry,
+			       &self->rule));
+}
+
+TEST_HARNESS_MAIN