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@xxxxxxxxxxxxx>
---
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
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
--
2.25.1
