+static int address_drop_handler(sd_rtnl *rtnl, sd_rtnl_message *m, void *userdata) {
+ Link *link = userdata;
+ int r;
+
+ assert(m);
+ assert(link);
+ assert(link->ifname);
+
+ if (link->state == LINK_STATE_FAILED)
+ return 1;
+
+ r = sd_rtnl_message_get_errno(m);
+ if (r < 0 && r != -EEXIST)
+ log_warning_link(link, "could not drop address: %s", strerror(-r));
+
+ return 1;
+}
+
+static void dhcp_handler(sd_dhcp_client *client, int event, void *userdata) {
+ Link *link = userdata;
+ struct in_addr address;
+ struct in_addr netmask;
+ struct in_addr gateway;
+ int prefixlen;
+ int r;
+
+ assert(link);
+
+ if (link->state == LINK_STATE_FAILED)
+ return;
+
+ if (event < 0) {
+ log_warning_link(link, "DHCP error: %s", strerror(-event));
+ link_enter_failed(link);
+ return;
+ }
+
+ if (event == DHCP_EVENT_NO_LEASE)
+ log_debug_link(link, "IP address in use.");
+
+ if (event == DHCP_EVENT_IP_CHANGE || event == DHCP_EVENT_EXPIRED ||
+ event == DHCP_EVENT_STOP) {
+ if (link->dhcp_address) {
+ address_drop(link->dhcp_address, link, address_drop_handler);
+
+ address_free(link->dhcp_address);
+ link->dhcp_address = NULL;
+ }
+
+ if (link->dhcp_route) {
+ route_free(link->dhcp_route);
+ link->dhcp_route = NULL;
+ }
+ }
+
+ r = sd_dhcp_client_get_address(client, &address);
+ if (r < 0) {
+ log_warning_link(link, "DHCP error: no address");
+ link_enter_failed(link);
+ return;
+ }
+
+ r = sd_dhcp_client_get_netmask(client, &netmask);
+ if (r < 0) {
+ log_warning_link(link, "DHCP error: no netmask");
+ link_enter_failed(link);
+ return;
+ }
+
+ prefixlen = sd_dhcp_client_prefixlen(&netmask);
+ if (prefixlen < 0) {
+ log_warning_link(link, "DHCP error: no prefixlen");
+ link_enter_failed(link);
+ return;
+ }
+
+ r = sd_dhcp_client_get_router(client, &gateway);
+ if (r < 0) {
+ log_warning_link(link, "DHCP error: no router");
+ link_enter_failed(link);
+ return;
+ }
+
+ if (event == DHCP_EVENT_IP_CHANGE || event == DHCP_EVENT_IP_ACQUIRE) {
+ _cleanup_address_free_ Address *addr = NULL;
+ _cleanup_route_free_ Route *rt = NULL;
+ struct in_addr **nameservers;
+
+ log_struct_link(LOG_INFO, link,
+ "MESSAGE=%s: DHCPv4 address %u.%u.%u.%u/%u via %u.%u.%u.%u",
+ link->ifname,
+ ADDRESS_FMT_VAL(address),
+ prefixlen,
+ ADDRESS_FMT_VAL(gateway),
+ "ADDRESS=%u.%u.%u.%u",
+ ADDRESS_FMT_VAL(address),
+ "PREFIXLEN=%u",
+ prefixlen,
+ "GATEWAY=%u.%u.%u.%u",
+ ADDRESS_FMT_VAL(gateway),
+ NULL);
+
+ r = address_new_dynamic(&addr);
+ if (r < 0) {
+ log_error_link(link, "Could not allocate address");
+ link_enter_failed(link);
+ return;
+ }
+
+ addr->family = AF_INET;
+ addr->in_addr.in = address;
+ addr->prefixlen = prefixlen;
+ addr->netmask = netmask;
+
+ r = route_new_dynamic(&rt);
+ if (r < 0) {
+ log_error_link(link, "Could not allocate route");
+ link_enter_failed(link);
+ return;
+ }
+
+ rt->family = AF_INET;
+ rt->in_addr.in = gateway;
+
+ link->dhcp_address = addr;
+ link->dhcp_route = rt;
+ addr = NULL;
+ rt = NULL;
+
+ r = sd_dhcp_client_get_dns(client, &nameservers);
+ if (r >= 0) {
+ r = manager_update_resolv_conf(link->manager);
+ if (r < 0)
+ log_error("Failed to update resolv.conf");
+ }
+
+ link_enter_set_addresses(link);
+ }
+
+ return;
+}
+
+static int link_acquire_conf(Link *link) {
+ int r;
+
+ assert(link);
+ assert(link->network);
+ assert(link->network->dhcp);
+ assert(link->manager);
+ assert(link->manager->event);
+
+ if (!link->dhcp) {
+ link->dhcp = sd_dhcp_client_new(link->manager->event);
+ if (!link->dhcp)
+ return -ENOMEM;
+
+ r = sd_dhcp_client_set_index(link->dhcp, link->ifindex);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_set_mac(link->dhcp, &link->mac);
+ if (r < 0)
+ return r;
+
+ r = sd_dhcp_client_set_callback(link->dhcp, dhcp_handler, link);
+ if (r < 0)
+ return r;
+ }
+
+ log_debug_link(link, "acquiring DHCPv4 lease");
+
+ r = sd_dhcp_client_start(link->dhcp);
+ 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,
+ "power %s", flags & IFF_UP ? "on": "off");
+
+ 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) {
+ r = link_acquire_conf(link);
+ if (r < 0) {
+ link_enter_failed(link);
+ return r;
+ }
+ }
+ } else {
+ log_info_link(link, "carrier off");
+
+ if (link->network->dhcp) {
+ r = sd_dhcp_client_stop(link->dhcp);
+ if (r < 0) {
+ link_enter_failed(link);
+ return r;
+ }
+ }
+ }
+ }
+
+ log_debug_link(link,
+ "link status updated: %#.8x -> %#.8x", link->flags, flags);
+
+ link->flags = flags;
+
+ return 0;
+}
+