selftests/net: Add trace events matching to tcp_ao

Setup trace points, add a new ftrace instance in order to not interfere with the rest of the system, filtering by net namespace cookies. Raise a new background thread that parses trace_pipe, matches them with the list of expected events. Wiring up trace events to selftests provides another insight if there is anything unexpected happining in the tcp-ao code (i.e. key rotation when it's not expected). Note: in real programs libtraceevent should be used instead of this manual labor of setting ftrace up and parsing. I'm not using it here as I don't want to have an .so library dependency that one would have to bring into VM or DUT (Device Under Test). Please, don't copy it over into any real world programs, that aren't tests. Signed-off-by: Dmitry Safonov <0x7f454c46@gmail.com> Link: https://patch.msgid.link/20240823-tcp-ao-selftests-upd-6-12-v4-8-05623636fe8c@gmail.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
author: Dmitry Safonov <0x7f454c46@gmail.com> 2024-08-23 23:04:58 +0100
committer: Jakub Kicinski <kuba@kernel.org> 2024-08-27 14:11:27 -0700
commit: 586d87021f224b0434372f5b4418216e29b0a544 (patch)
tree: 4455fded839323f5a798e878cbd97118ab970191 /tools/testing/selftests/net/tcp_ao/lib/ftrace.c
parent: 044e037051252ca8df07e1355bf4d7964645a6e8 (diff)
1 files changed, 543 insertions, 0 deletions
diff --git a/tools/testing/selftests/net/tcp_ao/lib/ftrace.c b/tools/testing/selftests/net/tcp_ao/lib/ftrace.c
new file mode 100644
index 000000000000..e4d0b173bc94
--- /dev/null
+++ b/tools/testing/selftests/net/tcp_ao/lib/ftrace.c
@@ -0,0 +1,543 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mount.h>
+#include <sys/time.h>
+#include <unistd.h>
+#include "../../../../../include/linux/kernel.h"
+#include "aolib.h"
+
+static char ftrace_path[] = "ksft-ftrace-XXXXXX";
+static bool ftrace_mounted;
+uint64_t ns_cookie1, ns_cookie2;
+
+struct test_ftracer {
+	pthread_t tracer_thread;
+	int	error;
+	char	*instance_path;
+	FILE	*trace_pipe;
+
+	enum ftracer_op (*process_line)(const char *line);
+	void (*destructor)(struct test_ftracer *tracer);
+	bool (*expecting_more)(void);
+
+	char	**saved_lines;
+	size_t	saved_lines_size;
+	size_t	next_line_ind;
+
+	pthread_cond_t met_all_expected;
+	pthread_mutex_t met_all_expected_lock;
+
+	struct test_ftracer *next;
+};
+
+static struct test_ftracer *ftracers;
+static pthread_mutex_t ftracers_lock = PTHREAD_MUTEX_INITIALIZER;
+
+static int mount_ftrace(void)
+{
+	if (!mkdtemp(ftrace_path))
+		test_error("Can't create temp dir");
+
+	if (mount("tracefs", ftrace_path, "tracefs", 0, "rw"))
+		return -errno;
+
+	ftrace_mounted = true;
+
+	return 0;
+}
+
+static void unmount_ftrace(void)
+{
+	if (ftrace_mounted && umount(ftrace_path))
+		test_print("Failed on cleanup: can't unmount tracefs: %m");
+
+	if (rmdir(ftrace_path))
+		test_error("Failed on cleanup: can't remove ftrace dir %s",
+			   ftrace_path);
+}
+
+struct opts_list_t {
+	char *opt_name;
+	struct opts_list_t *next;
+};
+
+static int disable_trace_options(const char *ftrace_path)
+{
+	struct opts_list_t *opts_list = NULL;
+	char *fopts, *line = NULL;
+	size_t buf_len = 0;
+	ssize_t line_len;
+	int ret = 0;
+	FILE *opts;
+
+	fopts = test_sprintf("%s/%s", ftrace_path, "trace_options");
+	if (!fopts)
+		return -ENOMEM;
+
+	opts = fopen(fopts, "r+");
+	if (!opts) {
+		ret = -errno;
+		goto out_free;
+	}
+
+	while ((line_len = getline(&line, &buf_len, opts)) != -1) {
+		struct opts_list_t *tmp;
+
+		if (!strncmp(line, "no", 2))
+			continue;
+
+		tmp = malloc(sizeof(*tmp));
+		if (!tmp) {
+			ret = -ENOMEM;
+			goto out_free_opts_list;
+		}
+		tmp->next = opts_list;
+		tmp->opt_name = test_sprintf("no%s", line);
+		if (!tmp->opt_name) {
+			ret = -ENOMEM;
+			free(tmp);
+			goto out_free_opts_list;
+		}
+		opts_list = tmp;
+	}
+
+	while (opts_list) {
+		struct opts_list_t *tmp = opts_list;
+
+		fseek(opts, 0, SEEK_SET);
+		fwrite(tmp->opt_name, 1, strlen(tmp->opt_name), opts);
+
+		opts_list = opts_list->next;
+		free(tmp->opt_name);
+		free(tmp);
+	}
+
+out_free_opts_list:
+	while (opts_list) {
+		struct opts_list_t *tmp = opts_list;
+
+		opts_list = opts_list->next;
+		free(tmp->opt_name);
+		free(tmp);
+	}
+	free(line);
+	fclose(opts);
+out_free:
+	free(fopts);
+	return ret;
+}
+
+static int setup_buffer_size(const char *ftrace_path, size_t sz)
+{
+	char *fbuf_size = test_sprintf("%s/buffer_size_kb", ftrace_path);
+	int ret;
+
+	if (!fbuf_size)
+		return -1;
+
+	ret = test_echo(fbuf_size, 0, "%zu", sz);
+	free(fbuf_size);
+	return ret;
+}
+
+static int setup_ftrace_instance(struct test_ftracer *tracer, const char *name)
+{
+	char *tmp;
+
+	tmp = test_sprintf("%s/instances/ksft-%s-XXXXXX", ftrace_path, name);
+	if (!tmp)
+		return -ENOMEM;
+
+	tracer->instance_path = mkdtemp(tmp);
+	if (!tracer->instance_path) {
+		free(tmp);
+		return -errno;
+	}
+
+	return 0;
+}
+
+static void remove_ftrace_instance(struct test_ftracer *tracer)
+{
+	if (rmdir(tracer->instance_path))
+		test_print("Failed on cleanup: can't remove ftrace instance %s",
+			   tracer->instance_path);
+	free(tracer->instance_path);
+}
+
+static void tracer_cleanup(void *arg)
+{
+	struct test_ftracer *tracer = arg;
+
+	fclose(tracer->trace_pipe);
+}
+
+static void tracer_set_error(struct test_ftracer *tracer, int error)
+{
+	if (!tracer->error)
+		tracer->error = error;
+}
+
+const size_t tracer_get_savedlines_nr(struct test_ftracer *tracer)
+{
+	return tracer->next_line_ind;
+}
+
+const char **tracer_get_savedlines(struct test_ftracer *tracer)
+{
+	return (const char **)tracer->saved_lines;
+}
+
+static void *tracer_thread_func(void *arg)
+{
+	struct test_ftracer *tracer = arg;
+
+	pthread_cleanup_push(tracer_cleanup, arg);
+
+	while (tracer->next_line_ind < tracer->saved_lines_size) {
+		char **lp = &tracer->saved_lines[tracer->next_line_ind];
+		enum ftracer_op op;
+		size_t buf_len = 0;
+		ssize_t line_len;
+
+		line_len = getline(lp, &buf_len, tracer->trace_pipe);
+		if (line_len == -1)
+			break;
+
+		pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, NULL);
+		op = tracer->process_line(*lp);
+		pthread_setcancelstate(PTHREAD_CANCEL_ENABLE, NULL);
+
+		if (tracer->expecting_more) {
+			pthread_mutex_lock(&tracer->met_all_expected_lock);
+			if (!tracer->expecting_more())
+				pthread_cond_signal(&tracer->met_all_expected);
+			pthread_mutex_unlock(&tracer->met_all_expected_lock);
+		}
+
+		if (op == FTRACER_LINE_DISCARD)
+			continue;
+		if (op == FTRACER_EXIT)
+			break;
+		if (op != FTRACER_LINE_PRESERVE)
+			test_error("unexpected tracer command %d", op);
+
+		tracer->next_line_ind++;
+		buf_len = 0;
+	}
+	test_print("too many lines in ftracer buffer %zu, exiting tracer",
+		   tracer->next_line_ind);
+
+	pthread_cleanup_pop(1);
+	return NULL;
+}
+
+static int setup_trace_thread(struct test_ftracer *tracer)
+{
+	int ret = 0;
+	char *path;
+
+	path = test_sprintf("%s/trace_pipe", tracer->instance_path);
+	if (!path)
+		return -ENOMEM;
+
+	tracer->trace_pipe = fopen(path, "r");
+	if (!tracer->trace_pipe) {
+		ret = -errno;
+		goto out_free;
+	}
+
+	if (pthread_create(&tracer->tracer_thread, NULL,
+			   tracer_thread_func, (void *)tracer)) {
+		ret = -errno;
+		fclose(tracer->trace_pipe);
+	}
+
+out_free:
+	free(path);
+	return ret;
+}
+
+static void stop_trace_thread(struct test_ftracer *tracer)
+{
+	void *res;
+
+	if (pthread_cancel(tracer->tracer_thread)) {
+		test_print("Can't stop tracer pthread: %m");
+		tracer_set_error(tracer, -errno);
+	}
+	if (pthread_join(tracer->tracer_thread, &res)) {
+		test_print("Can't join tracer pthread: %m");
+		tracer_set_error(tracer, -errno);
+	}
+	if (res != PTHREAD_CANCELED) {
+		test_print("Tracer thread wasn't canceled");
+		tracer_set_error(tracer, -errno);
+	}
+	if (tracer->error)
+		test_fail("tracer errored by %s", strerror(tracer->error));
+}
+
+static void final_wait_for_events(struct test_ftracer *tracer,
+				  unsigned timeout_sec)
+{
+	struct timespec timeout;
+	struct timeval now;
+	int ret = 0;
+
+	if (!tracer->expecting_more)
+		return;
+
+	pthread_mutex_lock(&tracer->met_all_expected_lock);
+	gettimeofday(&now, NULL);
+	timeout.tv_sec = now.tv_sec + timeout_sec;
+	timeout.tv_nsec = now.tv_usec * 1000;
+
+	while (tracer->expecting_more() && ret != ETIMEDOUT)
+		ret = pthread_cond_timedwait(&tracer->met_all_expected,
+				&tracer->met_all_expected_lock, &timeout);
+	pthread_mutex_unlock(&tracer->met_all_expected_lock);
+}
+
+int setup_trace_event(struct test_ftracer *tracer,
+		      const char *event, const char *filter)
+{
+	char *enable_path, *filter_path, *instance = tracer->instance_path;
+	int ret;
+
+	enable_path = test_sprintf("%s/events/%s/enable", instance, event);
+	if (!enable_path)
+		return -ENOMEM;
+
+	filter_path = test_sprintf("%s/events/%s/filter", instance, event);
+	if (!filter_path) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+
+	ret = test_echo(filter_path, 0, "%s", filter);
+	if (!ret)
+		ret = test_echo(enable_path, 0, "1");
+
+out_free:
+	free(filter_path);
+	free(enable_path);
+	return ret;
+}
+
+struct test_ftracer *create_ftracer(const char *name,
+				    enum ftracer_op (*process_line)(const char *line),
+				    void (*destructor)(struct test_ftracer *tracer),
+				    bool (*expecting_more)(void),
+				    size_t lines_buf_sz, size_t buffer_size_kb)
+{
+	struct test_ftracer *tracer;
+	int err;
+
+	/* XXX: separate __create_ftracer() helper and do here
+	 * if (!kernel_config_has(KCONFIG_FTRACE))
+	 *	return NULL;
+	 */
+
+	tracer = malloc(sizeof(*tracer));
+	if (!tracer) {
+		test_print("malloc()");
+		return NULL;
+	}
+
+	memset(tracer, 0, sizeof(*tracer));
+
+	err = setup_ftrace_instance(tracer, name);
+	if (err) {
+		test_print("setup_ftrace_instance(): %d", err);
+		goto err_free;
+	}
+
+	err = disable_trace_options(tracer->instance_path);
+	if (err) {
+		test_print("disable_trace_options(): %d", err);
+		goto err_remove;
+	}
+
+	err = setup_buffer_size(tracer->instance_path, buffer_size_kb);
+	if (err) {
+		test_print("disable_trace_options(): %d", err);
+		goto err_remove;
+	}
+
+	tracer->saved_lines = calloc(lines_buf_sz, sizeof(tracer->saved_lines[0]));
+	if (!tracer->saved_lines) {
+		test_print("calloc()");
+		goto err_remove;
+	}
+	tracer->saved_lines_size = lines_buf_sz;
+
+	tracer->process_line	= process_line;
+	tracer->destructor	= destructor;
+	tracer->expecting_more	= expecting_more;
+
+	err = pthread_cond_init(&tracer->met_all_expected, NULL);
+	if (err) {
+		test_print("pthread_cond_init(): %d", err);
+		goto err_free_lines;
+	}
+
+	err = pthread_mutex_init(&tracer->met_all_expected_lock, NULL);
+	if (err) {
+		test_print("pthread_mutex_init(): %d", err);
+		goto err_cond_destroy;
+	}
+
+	err = setup_trace_thread(tracer);
+	if (err) {
+		test_print("setup_trace_thread(): %d", err);
+		goto err_mutex_destroy;
+	}
+
+	pthread_mutex_lock(&ftracers_lock);
+	tracer->next = ftracers;
+	ftracers = tracer;
+	pthread_mutex_unlock(&ftracers_lock);
+
+	return tracer;
+
+err_mutex_destroy:
+	pthread_mutex_destroy(&tracer->met_all_expected_lock);
+err_cond_destroy:
+	pthread_cond_destroy(&tracer->met_all_expected);
+err_free_lines:
+	free(tracer->saved_lines);
+err_remove:
+	remove_ftrace_instance(tracer);
+err_free:
+	free(tracer);
+	return NULL;
+}
+
+static void __destroy_ftracer(struct test_ftracer *tracer)
+{
+	size_t i;
+
+	final_wait_for_events(tracer, TEST_TIMEOUT_SEC);
+	stop_trace_thread(tracer);
+	remove_ftrace_instance(tracer);
+	if (tracer->destructor)
+		tracer->destructor(tracer);
+	for (i = 0; i < tracer->saved_lines_size; i++)
+		free(tracer->saved_lines[i]);
+	pthread_cond_destroy(&tracer->met_all_expected);
+	pthread_mutex_destroy(&tracer->met_all_expected_lock);
+	free(tracer);
+}
+
+void destroy_ftracer(struct test_ftracer *tracer)
+{
+	pthread_mutex_lock(&ftracers_lock);
+	if (tracer == ftracers) {
+		ftracers = tracer->next;
+	} else {
+		struct test_ftracer *f = ftracers;
+
+		while (f->next != tracer) {
+			if (!f->next)
+				test_error("tracers list corruption or double free %p", tracer);
+			f = f->next;
+		}
+		f->next = tracer->next;
+	}
+	tracer->next = NULL;
+	pthread_mutex_unlock(&ftracers_lock);
+	__destroy_ftracer(tracer);
+}
+
+static void destroy_all_ftracers(void)
+{
+	struct test_ftracer *f;
+
+	pthread_mutex_lock(&ftracers_lock);
+	f = ftracers;
+	ftracers = NULL;
+	pthread_mutex_unlock(&ftracers_lock);
+
+	while (f) {
+		struct test_ftracer *n = f->next;
+
+		f->next = NULL;
+		__destroy_ftracer(f);
+		f = n;
+	}
+}
+
+static void test_unset_tracing(void)
+{
+	destroy_all_ftracers();
+	unmount_ftrace();
+}
+
+int test_setup_tracing(void)
+{
+	/*
+	 * Just a basic protection - this should be called only once from
+	 * lib/kconfig. Not thread safe, which is fine as it's early, before
+	 * threads are created.
+	 */
+	static int already_set;
+	int err;
+
+	if (already_set)
+		return -1;
+
+	/* Needs net-namespace cookies for filters */
+	if (ns_cookie1 == ns_cookie2) {
+		test_print("net-namespace cookies: %" PRIu64 " == %" PRIu64 ", can't set up tracing",
+			   ns_cookie1, ns_cookie2);
+		return -1;
+	}
+
+	already_set = 1;
+
+	test_add_destructor(test_unset_tracing);
+
+	err = mount_ftrace();
+	if (err) {
+		test_print("failed to mount_ftrace(): %d", err);
+		return err;
+	}
+
+	return setup_aolib_ftracer();
+}
+
+static int get_ns_cookie(int nsfd, uint64_t *out)
+{
+	int old_ns = switch_save_ns(nsfd);
+	socklen_t size = sizeof(*out);
+	int sk;
+
+	sk = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
+	if (sk < 0) {
+		test_print("socket(): %m");
+		return -errno;
+	}
+
+	if (getsockopt(sk, SOL_SOCKET, SO_NETNS_COOKIE, out, &size)) {
+		test_print("getsockopt(SO_NETNS_COOKIE): %m");
+		close(sk);
+		return -errno;
+	}
+
+	close(sk);
+	switch_close_ns(old_ns);
+	return 0;
+}
+
+void test_init_ftrace(int nsfd1, int nsfd2)
+{
+	get_ns_cookie(nsfd1, &ns_cookie1);
+	get_ns_cookie(nsfd2, &ns_cookie2);
+	/* Populate kernel config state */
+	kernel_config_has(KCONFIG_FTRACE);
+}
author	Dmitry Safonov <0x7f454c46@gmail.com>	2024-08-23 23:04:58 +0100
committer	Jakub Kicinski <kuba@kernel.org>	2024-08-27 14:11:27 -0700
commit	586d87021f224b0434372f5b4418216e29b0a544 (patch)
tree	4455fded839323f5a798e878cbd97118ab970191 /tools/testing/selftests/net/tcp_ao/lib/ftrace.c
parent	044e037051252ca8df07e1355bf4d7964645a6e8 (diff)