struct match_ops defines polymorphic interface for matches. A match
consists of pointers to struct match_ops and struct xt_entry_match which
contains a payload for the match's type.
All match_ops are kept in a map by their name.
Signed-off-by: Dmitrii Banshchikov <me@xxxxxxxxxxxxx>
---
net/bpfilter/Makefile | 3 +-
net/bpfilter/context.c | 44 +++++++++++++
net/bpfilter/context.h | 5 ++
net/bpfilter/match.c | 49 +++++++++++++++
net/bpfilter/match.h | 33 ++++++++++
net/bpfilter/xt_udp.c | 33 ++++++++++
.../testing/selftests/bpf/bpfilter/.gitignore | 1 +
tools/testing/selftests/bpf/bpfilter/Makefile | 7 +++
.../selftests/bpf/bpfilter/test_match.c | 63 +++++++++++++++++++
9 files changed, 237 insertions(+), 1 deletion(-)
create mode 100644 net/bpfilter/context.c
create mode 100644 net/bpfilter/match.c
create mode 100644 net/bpfilter/match.h
create mode 100644 net/bpfilter/xt_udp.c
create mode 100644 tools/testing/selftests/bpf/bpfilter/test_match.c
diff --git a/net/bpfilter/Makefile b/net/bpfilter/Makefile
index 1809759d08c4..59f2d35c1627 100644
--- a/net/bpfilter/Makefile
+++ b/net/bpfilter/Makefile
@@ -4,7 +4,8 @@
#
userprogs := bpfilter_umh
-bpfilter_umh-objs := main.o map-common.o
+bpfilter_umh-objs := main.o map-common.o match.o context.o
+bpfilter_umh-objs += xt_udp.o
userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi
ifeq ($(CONFIG_BPFILTER_UMH), y)
diff --git a/net/bpfilter/context.c b/net/bpfilter/context.c
new file mode 100644
index 000000000000..6b6203dd22a7
--- /dev/null
+++ b/net/bpfilter/context.c
@@ -0,0 +1,44 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#define _GNU_SOURCE
+
+#include "context.h"
+
+#include <linux/err.h>
+#include <linux/list.h>
+
+#include "map-common.h"
+#include "match.h"
+
+static int init_match_ops_map(struct context *ctx)
+{
+ const struct match_ops *match_ops[] = { &xt_udp };
+ int i, err;
+
+ err = create_map(&ctx->match_ops_map, ARRAY_SIZE(match_ops));
+ if (err)
+ return err;
+
+ for (i = 0; i < ARRAY_SIZE(match_ops); ++i) {
+ const struct match_ops *m = match_ops[i];
+
+ err = map_insert(&ctx->match_ops_map, m->name, (void *)m);
+ if (err)
+ return err;
+ }
+
+ return 0;
+}
+
+int create_context(struct context *ctx)
+{
+ return init_match_ops_map(ctx);
+}
+
+void free_context(struct context *ctx)
+{
+ free_map(&ctx->match_ops_map);
+}
diff --git a/net/bpfilter/context.h b/net/bpfilter/context.h
index e7bc27ee1ace..60bb525843b0 100644
--- a/net/bpfilter/context.h
+++ b/net/bpfilter/context.h
@@ -10,9 +10,11 @@
#include <stdio.h>
#include <stdlib.h>
+#include <search.h>
struct context {
FILE *log_file;
+ struct hsearch_data match_ops_map;
};
#define BFLOG_IMPL(ctx, level, fmt, ...) \
@@ -34,4 +36,7 @@ struct context {
#define BFLOG_DEBUG(ctx, fmt, ...)
#endif
+int create_context(struct context *ctx);
+void free_context(struct context *ctx);
+
#endif // NET_BPFILTER_CONTEXT_H
diff --git a/net/bpfilter/match.c b/net/bpfilter/match.c
new file mode 100644
index 000000000000..3b49196efabf
--- /dev/null
+++ b/net/bpfilter/match.c
@@ -0,0 +1,49 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#define _GNU_SOURCE
+
+#include "match.h"
+
+#include <linux/err.h>
+
+#include <errno.h>
+#include <string.h>
+
+#include "context.h"
+#include "map-common.h"
+
+int init_match(struct context *ctx, const struct bpfilter_ipt_match *ipt_match, struct match *match)
+{
+ const size_t maxlen = sizeof(ipt_match->u.user.name);
+ const struct match_ops *found;
+ int err;
+
+ if (strnlen(ipt_match->u.user.name, maxlen) == maxlen) {
+ BFLOG_DEBUG(ctx, "cannot init match: too long match name\n");
+ return -EINVAL;
+ }
+
+ found = map_find(&ctx->match_ops_map, ipt_match->u.user.name);
+ if (IS_ERR(found)) {
+ BFLOG_DEBUG(ctx, "cannot find match by name: '%s'\n", ipt_match->u.user.name);
+ return PTR_ERR(found);
+ }
+
+ if (found->size + sizeof(*ipt_match) != ipt_match->u.match_size ||
+ found->revision != ipt_match->u.user.revision) {
+ BFLOG_DEBUG(ctx, "invalid match: '%s'\n", ipt_match->u.user.name);
+ return -EINVAL;
+ }
+
+ err = found->check(ctx, ipt_match);
+ if (err)
+ return err;
+
+ match->match_ops = found;
+ match->ipt_match = ipt_match;
+
+ return 0;
+}
diff --git a/net/bpfilter/match.h b/net/bpfilter/match.h
new file mode 100644
index 000000000000..9879a3670711
--- /dev/null
+++ b/net/bpfilter/match.h
@@ -0,0 +1,33 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#ifndef NET_BPFILTER_MATCH_H
+#define NET_BPFILTER_MATCH_H
+
+#include "../../include/uapi/linux/bpfilter.h"
+
+#include <stdint.h>
+
+struct bpfilter_ipt_match;
+struct context;
+
+struct match_ops {
+ char name[BPFILTER_EXTENSION_MAXNAMELEN];
+ uint8_t revision;
+ uint16_t size;
+ int (*check)(struct context *ctx, const struct bpfilter_ipt_match *ipt_match);
+};
+
+struct match {
+ const struct match_ops *match_ops;
+ const struct bpfilter_ipt_match *ipt_match;
+};
+
+extern const struct match_ops xt_udp;
+
+int init_match(struct context *ctx, const struct bpfilter_ipt_match *ipt_match,
+ struct match *match);
+
+#endif // NET_BPFILTER_MATCH_H
diff --git a/net/bpfilter/xt_udp.c b/net/bpfilter/xt_udp.c
new file mode 100644
index 000000000000..a7fbe77a53cc
--- /dev/null
+++ b/net/bpfilter/xt_udp.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2021 Telegram FZ-LLC
+ */
+
+#define _GNU_SOURCE
+
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_tcpudp.h>
+
+#include <errno.h>
+
+#include "context.h"
+#include "match.h"
+
+static int xt_udp_check(struct context *ctx, const struct bpfilter_ipt_match *ipt_match)
+{
+ const struct xt_udp *udp;
+
+ udp = (const struct xt_udp *)&ipt_match->data;
+
+ if (udp->invflags & XT_UDP_INV_MASK) {
+ BFLOG_DEBUG(ctx, "cannot check match 'udp': invalid flags\n");
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+const struct match_ops xt_udp = { .name = "udp",
+ .size = XT_ALIGN(sizeof(struct xt_udp)),
+ .revision = 0,
+ .check = xt_udp_check };
diff --git a/tools/testing/selftests/bpf/bpfilter/.gitignore b/tools/testing/selftests/bpf/bpfilter/.gitignore
index 983fd06cbefa..9250411fa7aa 100644
--- a/tools/testing/selftests/bpf/bpfilter/.gitignore
+++ b/tools/testing/selftests/bpf/bpfilter/.gitignore
@@ -1,2 +1,3 @@
# SPDX-License-Identifier: GPL-2.0-only
test_map
+test_match
diff --git a/tools/testing/selftests/bpf/bpfilter/Makefile b/tools/testing/selftests/bpf/bpfilter/Makefile
index 647229a0596c..0ef156cdb198 100644
--- a/tools/testing/selftests/bpf/bpfilter/Makefile
+++ b/tools/testing/selftests/bpf/bpfilter/Makefile
@@ -9,9 +9,16 @@ BPFILTERSRCDIR := $(top_srcdir)/net/bpfilter
CFLAGS += -Wall -g -pthread -I$(TOOLSINCDIR) -I$(APIDIR) -I$(BPFILTERSRCDIR)
TEST_GEN_PROGS += test_map
+TEST_GEN_PROGS += test_match
KSFT_KHDR_INSTALL := 1
include ../../lib.mk
+BPFILTER_MATCH_SRCS := $(BPFILTERSRCDIR)/match.c $(BPFILTERSRCDIR)/xt_udp.c
+
+BPFILTER_COMMON_SRCS := $(BPFILTERSRCDIR)/map-common.c $(BPFILTERSRCDIR)/context.c
+BPFILTER_COMMON_SRCS += $(BPFILTER_MATCH_SRCS)
+
$(OUTPUT)/test_map: test_map.c $(BPFILTERSRCDIR)/map-common.c
+$(OUTPUT)/test_match: test_match.c $(BPFILTER_COMMON_SRCS) $(BPFILTER_MATCH_SRCS)
diff --git a/tools/testing/selftests/bpf/bpfilter/test_match.c b/tools/testing/selftests/bpf/bpfilter/test_match.c
new file mode 100644
index 000000000000..3a56d79ed24c
--- /dev/null
+++ b/tools/testing/selftests/bpf/bpfilter/test_match.c
@@ -0,0 +1,63 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+
+#include "context.h"
+#include "match.h"
+
+#include <linux/bpfilter.h>
+#include <linux/err.h>
+
+#include <linux/netfilter_ipv4/ip_tables.h>
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_tcpudp.h>
+
+#include <stdio.h>
+
+#include "../../kselftest_harness.h"
+
+struct udp_match {
+ struct xt_entry_match ipt_match;
+ struct xt_udp udp;
+};
+
+FIXTURE(test_udp_match)
+{
+ struct context ctx;
+ struct udp_match udp_match;
+ struct match match;
+};
+
+FIXTURE_SETUP(test_udp_match)
+{
+ ASSERT_EQ(0, create_context(&self->ctx));
+ self->ctx.log_file = stderr;
+
+ memset(&self->udp_match, 0, sizeof(self->udp_match));
+ snprintf(self->udp_match.ipt_match.u.user.name,
+ sizeof(self->udp_match.ipt_match.u.user.name), "udp");
+ self->udp_match.ipt_match.u.user.match_size = sizeof(struct udp_match);
+ self->udp_match.ipt_match.u.user.revision = 0;
+};
+
+FIXTURE_TEARDOWN(test_udp_match)
+{
+ free_context(&self->ctx);
+}
+
+TEST_F(test_udp_match, init)
+{
+ self->udp_match.udp.spts[0] = 1;
+ self->udp_match.udp.spts[1] = 2;
+ self->udp_match.udp.dpts[0] = 3;
+ self->udp_match.udp.dpts[1] = 4;
+ self->udp_match.udp.invflags = 0;
+
+ ASSERT_EQ(init_match(&self->ctx,
+ (const struct bpfilter_ipt_match *)&self->udp_match
+ .ipt_match,
+ &self->match),
+ 0);
+}
+
+TEST_HARNESS_MAIN
--
2.25.1
