bpf, selftests: Add cgroup v1 net_cls classid helpers (d8079d80) · Commits · EulixOS / Software / Kernel

tools/testing/selftests/bpf/cgroup_helpers.c

+128 −9

Original line number	Diff line number	Diff line
		@@ -12,27 +12,36 @@
		#include <unistd.h>
		#include <ftw.h>


		#include "cgroup_helpers.h"

		/*
		* To avoid relying on the system setup, when setup_cgroup_env is called
		* we create a new mount namespace, and cgroup namespace. The cgroup2
		* root is mounted at CGROUP_MOUNT_PATH
		*
		* Unfortunately, most people don't have cgroupv2 enabled at this point in time.
		* It's easier to create our own mount namespace and manage it ourselves.
		* we create a new mount namespace, and cgroup namespace. The cgroupv2
		* root is mounted at CGROUP_MOUNT_PATH. Unfortunately, most people don't
		* have cgroupv2 enabled at this point in time. It's easier to create our
		* own mount namespace and manage it ourselves. We assume /mnt exists.
		*
		* We assume /mnt exists.
		* Related cgroupv1 helpers are named classid(), since we only use the
		* net_cls controller for tagging net_cls.classid. We assume the default
		* mount under /sys/fs/cgroup/net_cls, which should be the case for the
		* vast majority of users.
		*/

		#define WALK_FD_LIMIT 16

		#define CGROUP_MOUNT_PATH "/mnt"
		#define CGROUP_MOUNT_DFLT "/sys/fs/cgroup"
		#define NETCLS_MOUNT_PATH CGROUP_MOUNT_DFLT "/net_cls"
		#define CGROUP_WORK_DIR "/cgroup-test-work-dir"

		#define format_cgroup_path(buf, path) \
		snprintf(buf, sizeof(buf), "%s%s%s", CGROUP_MOUNT_PATH, \
		CGROUP_WORK_DIR, path)

		#define format_classid_path(buf) \
		snprintf(buf, sizeof(buf), "%s%s", NETCLS_MOUNT_PATH, \
		CGROUP_WORK_DIR)

		/**
		* enable_all_controllers() - Enable all available cgroup v2 controllers
		*
		@@ -139,8 +148,7 @@ static int nftwfunc(const char filename, const struct stat statptr,
		return 0;
		}


		static int join_cgroup_from_top(char *cgroup_path)
		static int join_cgroup_from_top(const char *cgroup_path)
		{
		char cgroup_procs_path[PATH_MAX + 1];
		pid_t pid = getpid();
		@@ -313,3 +321,114 @@ int cgroup_setup_and_join(const char *path) {
		}
		return cg_fd;
		}

		/**
		* setup_classid_environment() - Setup the cgroupv1 net_cls environment
		*
		* After calling this function, cleanup_classid_environment should be called
		* once testing is complete.
		*
		* This function will print an error to stderr and return 1 if it is unable
		* to setup the cgroup environment. If setup is successful, 0 is returned.
		*/
		int setup_classid_environment(void)
		{
		char cgroup_workdir[PATH_MAX + 1];

		format_classid_path(cgroup_workdir);

		if (mount("tmpfs", CGROUP_MOUNT_DFLT, "tmpfs", 0, NULL) &&
		errno != EBUSY) {
		log_err("mount cgroup base");
		return 1;
		}

		if (mkdir(NETCLS_MOUNT_PATH, 0777) && errno != EEXIST) {
		log_err("mkdir cgroup net_cls");
		return 1;
		}

		if (mount("net_cls", NETCLS_MOUNT_PATH, "cgroup", 0, "net_cls") &&
		errno != EBUSY) {
		log_err("mount cgroup net_cls");
		return 1;
		}

		cleanup_classid_environment();

		if (mkdir(cgroup_workdir, 0777) && errno != EEXIST) {
		log_err("mkdir cgroup work dir");
		return 1;
		}

		return 0;
		}

		/**
		* set_classid() - Set a cgroupv1 net_cls classid
		* @id: the numeric classid
		*
		* Writes the passed classid into the cgroup work dir's net_cls.classid
		* file in order to later on trigger socket tagging.
		*
		* On success, it returns 0, otherwise on failure it returns 1. If there
		* is a failure, it prints the error to stderr.
		*/
		int set_classid(unsigned int id)
		{
		char cgroup_workdir[PATH_MAX - 42];
		char cgroup_classid_path[PATH_MAX + 1];
		int fd, rc = 0;

		format_classid_path(cgroup_workdir);
		snprintf(cgroup_classid_path, sizeof(cgroup_classid_path),
		"%s/net_cls.classid", cgroup_workdir);

		fd = open(cgroup_classid_path, O_WRONLY);
		if (fd < 0) {
		log_err("Opening cgroup classid: %s", cgroup_classid_path);
		return 1;
		}

		if (dprintf(fd, "%u\n", id) < 0) {
		log_err("Setting cgroup classid");
		rc = 1;
		}

		close(fd);
		return rc;
		}

		/**
		* join_classid() - Join a cgroupv1 net_cls classid
		*
		* This function expects the cgroup work dir to be already created, as we
		* join it here. This causes the process sockets to be tagged with the given
		* net_cls classid.
		*
		* On success, it returns 0, otherwise on failure it returns 1.
		*/
		int join_classid(void)
		{
		char cgroup_workdir[PATH_MAX + 1];

		format_classid_path(cgroup_workdir);
		return join_cgroup_from_top(cgroup_workdir);
		}

		/**
		* cleanup_classid_environment() - Cleanup the cgroupv1 net_cls environment
		*
		* At call time, it moves the calling process to the root cgroup, and then
		* runs the deletion process.
		*
		* On failure, it will print an error to stderr, and try to continue.
		*/
		void cleanup_classid_environment(void)
		{
		char cgroup_workdir[PATH_MAX + 1];

		format_classid_path(cgroup_workdir);
		join_cgroup_from_top(NETCLS_MOUNT_PATH);
		nftw(cgroup_workdir, nftwfunc, WALK_FD_LIMIT, FTW_DEPTH \| FTW_MOUNT);
		}

tools/testing/selftests/bpf/cgroup_helpers.h

+13 −3

Original line number	Diff line number	Diff line
		/* SPDX-License-Identifier: GPL-2.0 */
		#ifndef __CGROUP_HELPERS_H
		#define __CGROUP_HELPERS_H

		#include <errno.h>
		#include <string.h>

		@@ -8,12 +9,21 @@
		#define log_err(MSG, ...) fprintf(stderr, "(%s:%d: errno: %s) " MSG "\n", \
		__FILE__, __LINE__, clean_errno(), ##__VA_ARGS__)


		/* cgroupv2 related */
		int cgroup_setup_and_join(const char *path);
		int create_and_get_cgroup(const char *path);
		unsigned long long get_cgroup_id(const char *path);

		int join_cgroup(const char *path);

		int setup_cgroup_environment(void);
		void cleanup_cgroup_environment(void);
		unsigned long long get_cgroup_id(const char *path);

		#endif
		/* cgroupv1 related */
		int set_classid(unsigned int id);
		int join_classid(void);

		int setup_classid_environment(void);
		void cleanup_classid_environment(void);

		#endif /* __CGROUP_HELPERS_H */