selftests/bpf: Add some tests with new bpf_program__attach_sockmap() APIs

Add a few more tests in sockmap_basic.c and sockmap_listen.c to
test bpf_link based APIs for SK_MSG and SK_SKB programs.
Link attach/detach/update are all tested.

All tests are passed.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reviewed-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Yonghong Song <yonghong.song@linux.dev>
Link: https://lore.kernel.org/r/20240410043547.3738448-1-yonghong.song@linux.devSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/prog_tests/sockmap_basic.c

@@ -131,6 +131,65 @@ static void test_skmsg_helpers(enum bpf_map_type map_type)
 	test_skmsg_load_helpers__destroy(skel);
 }
 
+static void test_skmsg_helpers_with_link(enum bpf_map_type map_type)
+{
+	struct bpf_program *prog, *prog_clone, *prog_clone2;
+	DECLARE_LIBBPF_OPTS(bpf_link_update_opts, opts);
+	struct test_skmsg_load_helpers *skel;
+	struct bpf_link *link, *link2;
+	int err, map;
+
+	skel = test_skmsg_load_helpers__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_skmsg_load_helpers__open_and_load"))
+		return;
+
+	prog = skel->progs.prog_msg_verdict;
+	prog_clone = skel->progs.prog_msg_verdict_clone;
+	prog_clone2 = skel->progs.prog_msg_verdict_clone2;
+	map = bpf_map__fd(skel->maps.sock_map);
+
+	link = bpf_program__attach_sockmap(prog, map);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_sockmap"))
+		goto out;
+
+	/* Fail since bpf_link for the same prog has been created. */
+	err = bpf_prog_attach(bpf_program__fd(prog), map, BPF_SK_MSG_VERDICT, 0);
+	if (!ASSERT_ERR(err, "bpf_prog_attach"))
+		goto out;
+
+	/* Fail since bpf_link for the same prog type has been created. */
+	link2 = bpf_program__attach_sockmap(prog_clone, map);
+	if (!ASSERT_ERR_PTR(link2, "bpf_program__attach_sockmap")) {
+		bpf_link__detach(link2);
+		goto out;
+	}
+
+	err = bpf_link__update_program(link, prog_clone);
+	if (!ASSERT_OK(err, "bpf_link__update_program"))
+		goto out;
+
+	/* Fail since a prog with different type attempts to do update. */
+	err = bpf_link__update_program(link, skel->progs.prog_skb_verdict);
+	if (!ASSERT_ERR(err, "bpf_link__update_program"))
+		goto out;
+
+	/* Fail since the old prog does not match the one in the kernel. */
+	opts.old_prog_fd = bpf_program__fd(prog_clone2);
+	opts.flags = BPF_F_REPLACE;
+	err = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), &opts);
+	if (!ASSERT_ERR(err, "bpf_link_update"))
+		goto out;
+
+	opts.old_prog_fd = bpf_program__fd(prog_clone);
+	opts.flags = BPF_F_REPLACE;
+	err = bpf_link_update(bpf_link__fd(link), bpf_program__fd(prog), &opts);
+	if (!ASSERT_OK(err, "bpf_link_update"))
+		goto out;
+out:
+	bpf_link__detach(link);
+	test_skmsg_load_helpers__destroy(skel);
+}
+
 static void test_sockmap_update(enum bpf_map_type map_type)
 {
 	int err, prog, src;
@@ -298,6 +357,40 @@ static void test_sockmap_skb_verdict_attach(enum bpf_attach_type first,
 	test_sockmap_skb_verdict_attach__destroy(skel);
 }
 
+static void test_sockmap_skb_verdict_attach_with_link(void)
+{
+	struct test_sockmap_skb_verdict_attach *skel;
+	struct bpf_program *prog;
+	struct bpf_link *link;
+	int err, map;
+
+	skel = test_sockmap_skb_verdict_attach__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "open_and_load"))
+		return;
+	prog = skel->progs.prog_skb_verdict;
+	map = bpf_map__fd(skel->maps.sock_map);
+	link = bpf_program__attach_sockmap(prog, map);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_sockmap"))
+		goto out;
+
+	bpf_link__detach(link);
+
+	err = bpf_prog_attach(bpf_program__fd(prog), map, BPF_SK_SKB_STREAM_VERDICT, 0);
+	if (!ASSERT_OK(err, "bpf_prog_attach"))
+		goto out;
+
+	/* Fail since attaching with the same prog/map has been done. */
+	link = bpf_program__attach_sockmap(prog, map);
+	if (!ASSERT_ERR_PTR(link, "bpf_program__attach_sockmap"))
+		bpf_link__detach(link);
+
+	err = bpf_prog_detach2(bpf_program__fd(prog), map, BPF_SK_SKB_STREAM_VERDICT);
+	if (!ASSERT_OK(err, "bpf_prog_detach2"))
+		goto out;
+out:
+	test_sockmap_skb_verdict_attach__destroy(skel);
+}
+
 static __u32 query_prog_id(int prog_fd)
 {
 	struct bpf_prog_info info = {};
@@ -532,6 +625,38 @@ static void test_sockmap_skb_verdict_peek(void)
 	test_sockmap_pass_prog__destroy(pass);
 }
 
+static void test_sockmap_skb_verdict_peek_with_link(void)
+{
+	struct test_sockmap_pass_prog *pass;
+	struct bpf_program *prog;
+	struct bpf_link *link;
+	int err, map;
+
+	pass = test_sockmap_pass_prog__open_and_load();
+	if (!ASSERT_OK_PTR(pass, "open_and_load"))
+		return;
+	prog = pass->progs.prog_skb_verdict;
+	map = bpf_map__fd(pass->maps.sock_map_rx);
+	link = bpf_program__attach_sockmap(prog, map);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_sockmap"))
+		goto out;
+
+	err = bpf_link__update_program(link, pass->progs.prog_skb_verdict_clone);
+	if (!ASSERT_OK(err, "bpf_link__update_program"))
+		goto out;
+
+	/* Fail since a prog with different attach type attempts to do update. */
+	err = bpf_link__update_program(link, pass->progs.prog_skb_parser);
+	if (!ASSERT_ERR(err, "bpf_link__update_program"))
+		goto out;
+
+	test_sockmap_skb_verdict_peek_helper(map);
+	ASSERT_EQ(pass->bss->clone_called, 1, "clone_called");
+out:
+	bpf_link__detach(link);
+	test_sockmap_pass_prog__destroy(pass);
+}
+
 static void test_sockmap_unconnected_unix(void)
 {
 	int err, map, stream = 0, dgram = 0, zero = 0;
@@ -796,6 +921,8 @@ void test_sockmap_basic(void)
 		test_sockmap_skb_verdict_attach(BPF_SK_SKB_STREAM_VERDICT,
 						BPF_SK_SKB_VERDICT);
 	}
+	if (test__start_subtest("sockmap skb_verdict attach_with_link"))
+		test_sockmap_skb_verdict_attach_with_link();
 	if (test__start_subtest("sockmap msg_verdict progs query"))
 		test_sockmap_progs_query(BPF_SK_MSG_VERDICT);
 	if (test__start_subtest("sockmap stream_parser progs query"))
@@ -812,6 +939,8 @@ void test_sockmap_basic(void)
 		test_sockmap_skb_verdict_fionread(false);
 	if (test__start_subtest("sockmap skb_verdict msg_f_peek"))
 		test_sockmap_skb_verdict_peek();
+	if (test__start_subtest("sockmap skb_verdict msg_f_peek with link"))
+		test_sockmap_skb_verdict_peek_with_link();
 	if (test__start_subtest("sockmap unconnected af_unix"))
 		test_sockmap_unconnected_unix();
 	if (test__start_subtest("sockmap one socket to many map entries"))
@@ -820,4 +949,8 @@ void test_sockmap_basic(void)
 		test_sockmap_many_maps();
 	if (test__start_subtest("sockmap same socket replace"))
 		test_sockmap_same_sock();
+	if (test__start_subtest("sockmap sk_msg attach sockmap helpers with link"))
+		test_skmsg_helpers_with_link(BPF_MAP_TYPE_SOCKMAP);
+	if (test__start_subtest("sockhash sk_msg attach sockhash helpers with link"))
+		test_skmsg_helpers_with_link(BPF_MAP_TYPE_SOCKHASH);
 }

tools/testing/selftests/bpf/prog_tests/sockmap_listen.c

@@ -767,6 +767,24 @@ static void test_msg_redir_to_connected(struct test_sockmap_listen *skel,
 	xbpf_prog_detach2(verdict, sock_map, BPF_SK_MSG_VERDICT);
 }
 
+static void test_msg_redir_to_connected_with_link(struct test_sockmap_listen *skel,
+						  struct bpf_map *inner_map, int family,
+						  int sotype)
+{
+	int prog_msg_verdict = bpf_program__fd(skel->progs.prog_msg_verdict);
+	int verdict_map = bpf_map__fd(skel->maps.verdict_map);
+	int sock_map = bpf_map__fd(inner_map);
+	int link_fd;
+
+	link_fd = bpf_link_create(prog_msg_verdict, sock_map, BPF_SK_MSG_VERDICT, NULL);
+	if (!ASSERT_GE(link_fd, 0, "bpf_link_create"))
+		return;
+
+	redir_to_connected(family, sotype, sock_map, verdict_map, REDIR_EGRESS);
+
+	close(link_fd);
+}
+
 static void redir_to_listening(int family, int sotype, int sock_mapfd,
 			       int verd_mapfd, enum redir_mode mode)
 {
@@ -869,6 +887,24 @@ static void test_msg_redir_to_listening(struct test_sockmap_listen *skel,
 	xbpf_prog_detach2(verdict, sock_map, BPF_SK_MSG_VERDICT);
 }
 
+static void test_msg_redir_to_listening_with_link(struct test_sockmap_listen *skel,
+						  struct bpf_map *inner_map, int family,
+						  int sotype)
+{
+	struct bpf_program *verdict = skel->progs.prog_msg_verdict;
+	int verdict_map = bpf_map__fd(skel->maps.verdict_map);
+	int sock_map = bpf_map__fd(inner_map);
+	struct bpf_link *link;
+
+	link = bpf_program__attach_sockmap(verdict, sock_map);
+	if (!ASSERT_OK_PTR(link, "bpf_program__attach_sockmap"))
+		return;
+
+	redir_to_listening(family, sotype, sock_map, verdict_map, REDIR_EGRESS);
+
+	bpf_link__detach(link);
+}
+
 static void redir_partial(int family, int sotype, int sock_map, int parser_map)
 {
 	int s, c0 = -1, c1 = -1, p0 = -1, p1 = -1;
@@ -1316,7 +1352,9 @@ static void test_redir(struct test_sockmap_listen *skel, struct bpf_map *map,
 		TEST(test_skb_redir_to_listening),
 		TEST(test_skb_redir_partial),
 		TEST(test_msg_redir_to_connected),
+		TEST(test_msg_redir_to_connected_with_link),
 		TEST(test_msg_redir_to_listening),
+		TEST(test_msg_redir_to_listening_with_link),
 	};
 	const char *family_name, *map_name;
 	const struct redir_test *t;

tools/testing/selftests/bpf/progs/test_skmsg_load_helpers.c

@@ -49,4 +49,22 @@ int prog_msg_verdict(struct sk_msg_md *msg)
 	return prog_msg_verdict_common(msg);
 }
 
+SEC("sk_msg")
+int prog_msg_verdict_clone(struct sk_msg_md *msg)
+{
+	return prog_msg_verdict_common(msg);
+}
+
+SEC("sk_msg")
+int prog_msg_verdict_clone2(struct sk_msg_md *msg)
+{
+	return prog_msg_verdict_common(msg);
+}
+
+SEC("sk_skb/stream_verdict")
+int prog_skb_verdict(struct __sk_buff *skb)
+{
+	return SK_PASS;
+}
+
 char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/test_sockmap_pass_prog.c

@@ -23,10 +23,25 @@ struct {
 	__type(value, int);
 } sock_map_msg SEC(".maps");
 
-SEC("sk_skb")
+SEC("sk_skb/stream_verdict")
 int prog_skb_verdict(struct __sk_buff *skb)
 {
 	return SK_PASS;
 }
 
+int clone_called;
+
+SEC("sk_skb/stream_verdict")
+int prog_skb_verdict_clone(struct __sk_buff *skb)
+{
+	clone_called = 1;
+	return SK_PASS;
+}
+
+SEC("sk_skb/stream_parser")
+int prog_skb_parser(struct __sk_buff *skb)
+{
+	return SK_PASS;
+}
+
 char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/progs/test_sockmap_skb_verdict_attach.c

@@ -9,7 +9,7 @@ struct {
 	__type(value, __u64);
 } sock_map SEC(".maps");
 
-SEC("sk_skb")
+SEC("sk_skb/verdict")
 int prog_skb_verdict(struct __sk_buff *skb)
 {
 	return SK_DROP;