[PATCH bpf-next 5/7] selftests: bpf: verify token of struct mptcp_sock

[Mat Martineau <mathew.j.martineau@linux.intel.com>]

From: Geliang Tang <geliang.tang@suse.com>

This patch verifies the struct member token of struct mptcp_sock. Add a
new function get_msk_token() to parse the msk token from the output of
the command 'ip mptcp monitor', and verify it in verify_msk().

Acked-by: Matthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <mathew.j.martineau@linux.intel.com>
---
 .../testing/selftests/bpf/bpf_mptcp_helpers.h |  1 +
 .../testing/selftests/bpf/prog_tests/mptcp.c  | 66 +++++++++++++++++++
 .../testing/selftests/bpf/progs/mptcp_sock.c  |  5 ++
 3 files changed, 72 insertions(+)

diff --git a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
index 18da4cc65e89..87e15810997d 100644
--- a/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
+++ b/tools/testing/selftests/bpf/bpf_mptcp_helpers.h
@@ -9,6 +9,7 @@
 struct mptcp_sock {
 	struct inet_connection_sock	sk;
 
+	__u32		token;
 } __attribute__((preserve_access_index));
 
 #endif
diff --git a/tools/testing/selftests/bpf/prog_tests/mptcp.c b/tools/testing/selftests/bpf/prog_tests/mptcp.c
index 4b40bbdaf91f..c5d96ba81e04 100644
--- a/tools/testing/selftests/bpf/prog_tests/mptcp.c
+++ b/tools/testing/selftests/bpf/prog_tests/mptcp.c
@@ -8,8 +8,11 @@
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	__u32 token;
 };
 
+static char monitor_log_path[64];
+
 static int verify_tsk(int map_fd, int client_fd)
 {
 	char *msg = "plain TCP socket";
@@ -36,11 +39,58 @@ static int verify_tsk(int map_fd, int client_fd)
 	return err;
 }
 
+/*
+ * Parse the token from the output of 'ip mptcp monitor':
+ *
+ * [       CREATED] token=3ca933d3 remid=0 locid=0 saddr4=127.0.0.1 ...
+ * [       CREATED] token=2ab57040 remid=0 locid=0 saddr4=127.0.0.1 ...
+ */
+static __u32 get_msk_token(void)
+{
+	char *prefix = "[       CREATED] token=";
+	char buf[BUFSIZ] = {};
+	__u32 token = 0;
+	ssize_t len;
+	int fd;
+
+	sync();
+
+	fd = open(monitor_log_path, O_RDONLY);
+	if (CHECK_FAIL(fd < 0)) {
+		log_err("Failed to open %s", monitor_log_path);
+		return token;
+	}
+
+	len = read(fd, buf, sizeof(buf));
+	if (CHECK_FAIL(len < 0)) {
+		log_err("Failed to read %s", monitor_log_path);
+		goto err;
+	}
+
+	if (strncmp(buf, prefix, strlen(prefix))) {
+		log_err("Invalid prefix %s", buf);
+		goto err;
+	}
+
+	token = strtol(buf + strlen(prefix), NULL, 16);
+
+err:
+	close(fd);
+	return token;
+}
+
 static int verify_msk(int map_fd, int client_fd)
 {
 	char *msg = "MPTCP subflow socket";
 	int err = 0, cfd = client_fd;
 	struct mptcp_storage val;
+	__u32 token;
+
+	token = get_msk_token();
+	if (token <= 0) {
+		log_err("Unexpected token %x", token);
+		return -1;
+	}
 
 	if (CHECK_FAIL(bpf_map_lookup_elem(map_fd, &cfd, &val) < 0)) {
 		perror("Failed to read socket storage");
@@ -59,6 +109,12 @@ static int verify_msk(int map_fd, int client_fd)
 		err++;
 	}
 
+	if (val.token != token) {
+		log_err("Unexpected mptcp_sock.token %x != %x",
+			val.token, token);
+		err++;
+	}
+
 	return err;
 }
 
@@ -124,6 +180,7 @@ static int run_test(int cgroup_fd, int server_fd, bool is_mptcp)
 
 void test_base(void)
 {
+	char cmd[256], tmp_dir[] = "/tmp/XXXXXX";
 	int server_fd, cgroup_fd;
 
 	cgroup_fd = test__join_cgroup("/mptcp");
@@ -141,6 +198,13 @@ void test_base(void)
 
 with_mptcp:
 	/* with MPTCP */
+	if (CHECK_FAIL(!mkdtemp(tmp_dir)))
+		goto close_cgroup_fd;
+	snprintf(monitor_log_path, sizeof(monitor_log_path),
+		 "%s/ip_mptcp_monitor", tmp_dir);
+	snprintf(cmd, sizeof(cmd), "ip mptcp monitor > %s &", monitor_log_path);
+	if (CHECK_FAIL(system(cmd)))
+		goto close_cgroup_fd;
 	server_fd = start_mptcp_server(AF_INET, NULL, 0, 0);
 	if (CHECK_FAIL(server_fd < 0))
 		goto close_cgroup_fd;
@@ -148,6 +212,8 @@ void test_base(void)
 	CHECK_FAIL(run_test(cgroup_fd, server_fd, true));
 
 	close(server_fd);
+	snprintf(cmd, sizeof(cmd), "rm -rf %s", tmp_dir);
+	system(cmd);
 
 close_cgroup_fd:
 	close(cgroup_fd);
diff --git a/tools/testing/selftests/bpf/progs/mptcp_sock.c b/tools/testing/selftests/bpf/progs/mptcp_sock.c
index 5cfaec4e7245..56cc7c61131b 100644
--- a/tools/testing/selftests/bpf/progs/mptcp_sock.c
+++ b/tools/testing/selftests/bpf/progs/mptcp_sock.c
@@ -11,6 +11,7 @@ __u32 _version SEC("version") = 1;
 struct mptcp_storage {
 	__u32 invoked;
 	__u32 is_mptcp;
+	__u32 token;
 };
 
 struct {
@@ -45,6 +46,8 @@ int _sockops(struct bpf_sock_ops *ctx)
 					     BPF_SK_STORAGE_GET_F_CREATE);
 		if (!storage)
 			return 1;
+
+		storage->token = 0;
 	} else {
 		msk = bpf_skc_to_mptcp_sock(sk);
 		if (!msk)
@@ -54,6 +57,8 @@ int _sockops(struct bpf_sock_ops *ctx)
 					     BPF_SK_STORAGE_GET_F_CREATE);
 		if (!storage)
 			return 1;
+
+		storage->token = msk->token;
 	}
 	storage->invoked++;
 	storage->is_mptcp = tcp_sk->is_mptcp;
-- 
2.36.0