+ if (link->network->dhcp) {
+ if (!link->dhcp_client) {
+ r = sd_dhcp_client_new(&link->dhcp_client);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_attach_event(link->dhcp_client, NULL, 0);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_set_index(link->dhcp_client, link->ifindex);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_set_mac(link->dhcp_client, &link->mac);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_set_callback(link->dhcp_client, dhcp_handler, link);
+ if (r < 0)
+ return r;
+
+ if (link->network->dhcp_mtu) {
+ r = sd_dhcp_client_set_request_option(link->dhcp_client, 26);
+ if (r < 0)
+ return r;
+ }
+ }
+
+ log_debug_link(link, "acquiring DHCPv4 lease");
+
+ r = sd_dhcp_client_start(link->dhcp_client);
+ if (r < 0)
+ return r;
+ }
+
+ return 0;
+}
+
+static int link_update_flags(Link *link, unsigned flags) {
+ int r;
+
+ assert(link);
+ assert(link->network);
+
+ if (link->state == LINK_STATE_FAILED)
+ return 0;
+
+ if (link->flags == flags) {
+ log_debug_link(link, "link status unchanged: %#.8x", flags);
+ return 0;
+ }
+
+ if ((link->flags & IFF_UP) != (flags & IFF_UP))
+ log_info_link(link,
+ "link is %s", flags & IFF_UP ? "up": "down");
+
+ if ((link->flags & IFF_LOWER_UP) != (flags & IFF_LOWER_UP)) {
+ if (flags & IFF_LOWER_UP) {
+ log_info_link(link, "carrier on");
+
+ if (link->network->dhcp || link->network->ipv4ll) {
+ r = link_acquire_conf(link);
+ if (r < 0) {
+ log_warning_link(link, "Could not acquire configuration: %s", strerror(-r));
+ link_enter_failed(link);
+ return r;
+ }
+ }
+ } else {
+ log_info_link(link, "carrier off");
+
+ if (link->network->dhcp) {
+ r = sd_dhcp_client_stop(link->dhcp_client);
+ if (r < 0) {
+ log_warning_link(link, "Could not stop DHCPv4 client: %s", strerror(-r));
+ link_enter_failed(link);
+ return r;
+ }
+ }
+
+ if (link->network->ipv4ll) {
+ r = sd_ipv4ll_stop(link->ipv4ll);
+ if (r < 0) {
+ log_warning_link(link, "Could not stop IPv4 link-local: %s", strerror(-r));
+ link_enter_failed(link);
+ return r;
+ }
+ }
+ }
+ }
+
+ log_debug_link(link,
+ "link status updated: %#.8x -> %#.8x", link->flags, flags);
+
+ link->flags = flags;
+