+
+/**
+ * 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);
+}