+static int unit_find_free_netclass_cgroup(Unit *u, uint32_t *ret) {
+
+ uint32_t start, i;
+ Manager *m;
+
+ assert(u);
+
+ m = u->manager;
+
+ i = start = m->cgroup_netclass_registry_last;
+
+ do {
+ i++;
+
+ if (!hashmap_get(m->cgroup_netclass_registry, UINT_TO_PTR(i))) {
+ m->cgroup_netclass_registry_last = i;
+ *ret = i;
+ return 0;
+ }
+
+ if (i == UINT32_MAX)
+ i = CGROUP_NETCLASS_FIXED_MAX;
+
+ } while (i != start);
+
+ return -ENOBUFS;
+}
+
+int unit_add_to_netclass_cgroup(Unit *u) {
+
+ CGroupContext *cc;
+ Unit *first;
+ void *key;
+ int r;
+
+ assert(u);
+
+ cc = unit_get_cgroup_context(u);
+ if (!cc)
+ return 0;
+
+ switch (cc->netclass_type) {
+ case CGROUP_NETCLASS_TYPE_NONE:
+ return 0;
+
+ case CGROUP_NETCLASS_TYPE_FIXED:
+ u->cgroup_netclass_id = cc->netclass_id;
+ break;
+
+ case CGROUP_NETCLASS_TYPE_AUTO:
+ /* Allocate a new ID in case it was requested and not done yet */
+ if (u->cgroup_netclass_id == 0) {
+ r = unit_find_free_netclass_cgroup(u, &u->cgroup_netclass_id);
+ if (r < 0)
+ return r;
+
+ log_debug("Dynamically assigned netclass cgroup id %" PRIu32 " to %s", u->cgroup_netclass_id, u->id);
+ }
+
+ break;
+ }
+
+ r = hashmap_ensure_allocated(&u->manager->cgroup_netclass_registry, &trivial_hash_ops);
+ if (r < 0)
+ return r;
+
+ key = UINT32_TO_PTR(u->cgroup_netclass_id);
+ first = hashmap_get(u->manager->cgroup_netclass_registry, key);
+
+ if (first) {
+ LIST_PREPEND(cgroup_netclass, first, u);
+ return hashmap_replace(u->manager->cgroup_netclass_registry, key, u);
+ }
+
+ return hashmap_put(u->manager->cgroup_netclass_registry, key, u);
+}
+
+int unit_remove_from_netclass_cgroup(Unit *u) {
+
+ Unit *head;
+ void *key;
+
+ assert(u);
+
+ key = UINT32_TO_PTR(u->cgroup_netclass_id);
+
+ LIST_FIND_HEAD(cgroup_netclass, u, head);
+ LIST_REMOVE(cgroup_netclass, head, u);
+
+ if (head)
+ return hashmap_replace(u->manager->cgroup_netclass_registry, key, head);
+
+ hashmap_remove(u->manager->cgroup_netclass_registry, key);
+
+ return 0;
+}
+