+static int link_down_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+ _cleanup_link_unref_ Link *link = userdata;
+ int r;
+
+ assert(link);
+
+ if (IN_SET(link->state, LINK_STATE_FAILED, LINK_STATE_LINGER))
+ return 1;
+
+ r = sd_rtnl_message_get_errno(m);
+ if (r < 0)
+ log_link_warning_errno(link, -r, "%-*s: could not bring down interface: %m", IFNAMSIZ, link->ifname);
+
+ return 1;
+}
+
+static int link_down(Link *link) {
+ _cleanup_rtnl_message_unref_ sd_rtnl_message *req = NULL;
+ int r;
+
+ assert(link);
+ assert(link->manager);
+ assert(link->manager->rtnl);
+
+ log_link_debug(link, "bringing link down");
+
+ r = sd_rtnl_message_new_link(link->manager->rtnl, &req,
+ RTM_SETLINK, link->ifindex);
+ if (r < 0) {
+ log_link_error(link, "Could not allocate RTM_SETLINK message");
+ return r;
+ }
+
+ r = sd_rtnl_message_link_set_flags(req, 0, IFF_UP);
+ if (r < 0) {
+ log_link_error(link, "Could not set link flags: %s",
+ strerror(-r));
+ return r;
+ }
+
+ r = sd_rtnl_call_async(link->manager->rtnl, req, link_down_handler, link,
+ 0, NULL);
+ if (r < 0) {
+ log_link_error(link,
+ "Could not send rtnetlink message: %s",
+ strerror(-r));
+ return r;
+ }
+
+ link_ref(link);
+
+ return 0;
+}
+
+static int link_handle_bound_to_list(Link *link) {
+ Link *l;
+ Iterator i;
+ int r;
+ bool required_up = false;
+ bool link_is_up = false;
+
+ assert(link);
+
+ if (hashmap_isempty(link->bound_to_links))
+ return 0;
+
+ if (link->flags & IFF_UP)
+ link_is_up = true;
+
+ HASHMAP_FOREACH (l, link->bound_to_links, i)
+ if (link_has_carrier(l)) {
+ required_up = true;
+ break;
+ }
+
+ if (!required_up && link_is_up) {
+ r = link_down(link);
+ if (r < 0)
+ return r;
+ } else if (required_up && !link_is_up) {
+ r = link_up(link);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int link_handle_bound_by_list(Link *link) {
+ Iterator i;
+ Link *l;
+ int r;
+
+ assert(link);
+
+ if (hashmap_isempty(link->bound_by_links))
+ return 0;
+
+ HASHMAP_FOREACH (l, link->bound_by_links, i) {
+ r = link_handle_bound_to_list(l);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int link_put_carrier(Link *link, Link *carrier, Hashmap **h) {
+ int r;
+
+ assert(link);
+ assert(carrier);
+
+ if (link == carrier)
+ return 0;
+
+ if (hashmap_get(*h, INT_TO_PTR(carrier->ifindex)))
+ return 0;
+
+ r = hashmap_ensure_allocated(h, NULL);
+ if (r < 0)
+ return r;
+
+ r = hashmap_put(*h, INT_TO_PTR(carrier->ifindex), carrier);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static int link_new_bound_by_list(Link *link) {
+ Manager *m;
+ Link *carrier;
+ Iterator i;
+ int r;
+ bool list_updated = false;
+
+ assert(link);
+ assert(link->manager);
+
+ m = link->manager;
+
+ HASHMAP_FOREACH (carrier, m->links, i) {
+ if (!carrier->network)
+ continue;
+
+ if (strv_isempty(carrier->network->bind_carrier))
+ continue;
+
+ if (strv_fnmatch(carrier->network->bind_carrier, link->ifname, 0)) {
+ r = link_put_carrier(link, carrier, &link->bound_by_links);
+ if (r < 0)
+ return r;
+
+ list_updated = true;
+ }
+ }
+
+ if (list_updated)
+ link_save(link);
+
+ HASHMAP_FOREACH (carrier, link->bound_by_links, i) {
+ r = link_put_carrier(carrier, link, &carrier->bound_to_links);
+ if (r < 0)
+ return r;
+
+ link_save(carrier);
+ }
+
+ return 0;
+}
+
+static int link_new_bound_to_list(Link *link) {
+ Manager *m;
+ Link *carrier;
+ Iterator i;
+ int r;
+ bool list_updated = false;
+
+ assert(link);
+ assert(link->manager);
+
+ if (!link->network)
+ return 0;
+
+ if (strv_isempty(link->network->bind_carrier))
+ return 0;
+
+ m = link->manager;
+
+ HASHMAP_FOREACH (carrier, m->links, i) {
+ if (strv_fnmatch(link->network->bind_carrier, carrier->ifname, 0)) {
+ r = link_put_carrier(link, carrier, &link->bound_to_links);
+ if (r < 0)
+ return r;
+
+ list_updated = true;
+ }
+ }
+
+ if (list_updated)
+ link_save(link);
+
+ HASHMAP_FOREACH (carrier, link->bound_to_links, i) {
+ r = link_put_carrier(carrier, link, &carrier->bound_by_links);
+ if (r < 0)
+ return r;
+
+ link_save(carrier);
+ }
+
+ return 0;
+}
+
+static int link_new_carrier_maps(Link *link) {
+ int r;
+
+ r = link_new_bound_by_list(link);
+ if (r < 0)
+ return r;
+
+ r = link_handle_bound_by_list(link);
+ if (r < 0)
+ return r;
+
+ r = link_new_bound_to_list(link);
+ if (r < 0)
+ return r;
+
+ r = link_handle_bound_to_list(link);
+ if (r < 0)
+ return r;
+
+ return 0;
+}
+
+static void link_free_bound_to_list(Link *link) {
+ Link *bound_to;
+ Iterator i;
+
+ HASHMAP_FOREACH (bound_to, link->bound_to_links, i) {
+ hashmap_remove(link->bound_to_links, INT_TO_PTR(bound_to->ifindex));
+
+ if (hashmap_remove(bound_to->bound_by_links, INT_TO_PTR(link->ifindex)))
+ link_save(bound_to);
+ }
+
+ return;
+}
+
+static void link_free_bound_by_list(Link *link) {
+ Link *bound_by;
+ Iterator i;
+
+ HASHMAP_FOREACH (bound_by, link->bound_by_links, i) {
+ hashmap_remove(link->bound_by_links, INT_TO_PTR(bound_by->ifindex));
+
+ if (hashmap_remove(bound_by->bound_to_links, INT_TO_PTR(link->ifindex))) {
+ link_save(bound_by);
+ link_handle_bound_to_list(bound_by);
+ }
+ }
+
+ return;
+}
+
+static void link_free_carrier_maps(Link *link) {
+ bool list_updated = false;
+
+ assert(link);
+
+ if (!hashmap_isempty(link->bound_to_links)) {
+ link_free_bound_to_list(link);
+ list_updated = true;
+ }
+
+ if (!hashmap_isempty(link->bound_by_links)) {
+ link_free_bound_by_list(link);
+ list_updated = true;
+ }
+
+ if (list_updated)
+ link_save(link);
+
+ return;
+}
+
+void link_drop(Link *link) {
+ if (!link || link->state == LINK_STATE_LINGER)
+ return;
+
+ link_set_state(link, LINK_STATE_LINGER);
+
+ link_free_carrier_maps(link);
+
+ log_link_debug(link, "link removed");
+
+ link_unref(link);
+
+ return;
+}
+