network/ipv4ll: introduce ipv4ll_start() helper function

No effective functional change. Just refactoring.

src/network/networkd-dhcp4.c

@@ -16,7 +16,7 @@
 #include "networkd-dhcp-prefix-delegation.h"
 #include "networkd-dhcp4-bus.h"
 #include "networkd-dhcp4.h"
-#include "networkd-ipv4acd.h"
+#include "networkd-ipv4ll.h"
 #include "networkd-link.h"
 #include "networkd-manager.h"
 #include "networkd-network.h"
@@ -1192,13 +1192,11 @@ static int dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
                                 return 0;
                         }
 
-                        if (link->ipv4ll && !sd_ipv4ll_is_running(link->ipv4ll)) {
-                                log_link_debug(link, "DHCP client is stopped. Acquiring IPv4 link-local address");
-
-                                r = sd_ipv4ll_start(link->ipv4ll);
-                                if (r < 0 && r != -ESTALE) /* On exit, we cannot and should not start sd-ipv4ll. */
-                                        return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
-                        }
+                        r = ipv4ll_start(link);
+                        if (r < 0)
+                                return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
+                        if (r > 0)
+                                log_link_debug(link, "DHCP client is stopped. Acquiring IPv4 link-local address.");
 
                         if (link->dhcp_lease) {
                                 if (link->network->dhcp_send_release) {
@@ -1270,13 +1268,11 @@ static int dhcp4_handler(sd_dhcp_client *client, int event, void *userdata) {
                         break;
 
                 case SD_DHCP_CLIENT_EVENT_TRANSIENT_FAILURE:
-                        if (link->ipv4ll && !sd_ipv4ll_is_running(link->ipv4ll)) {
+                        r = ipv4ll_start(link);
+                        if (r < 0)
+                                return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
+                        if (r > 0)
                                 log_link_debug(link, "Problems acquiring DHCP lease, acquiring IPv4 link-local address");
-
-                                r = sd_ipv4ll_start(link->ipv4ll);
-                                if (r < 0)
-                                        return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
-                        }
                         break;
 
                 default:

src/network/networkd-ipv4ll.c

@@ -264,6 +264,34 @@ int ipv4ll_configure(Link *link) {
         return sd_ipv4ll_set_check_mac_callback(link->ipv4ll, ipv4ll_check_mac, link->manager);
 }
 
+int ipv4ll_start(Link *link) {
+        int r;
+
+        assert(link);
+
+        if (!link->ipv4ll)
+                return 0;
+
+        if (sd_ipv4ll_is_running(link->ipv4ll))
+                return 0;
+
+        if (!link_has_carrier(link))
+                return 0;
+
+        /* On exit, we cannot and should not start sd-ipv4ll. */
+        r = sd_event_get_state(link->manager->event);
+        if (r < 0)
+                return r;
+        if (r == SD_EVENT_FINISHED)
+                return 0;
+
+        r = sd_ipv4ll_start(link->ipv4ll);
+        if (r < 0)
+                return r;
+
+        return 1; /* started */
+}
+
 int link_drop_ipv4ll_config(Link *link, Network *network) {
         int ret = 0;
 

src/network/networkd-ipv4ll.h

@@ -11,6 +11,7 @@ typedef struct Network Network;
 bool link_ipv4ll_enabled(Link *link);
 
 int ipv4ll_configure(Link *link);
+int ipv4ll_start(Link *link);
 int link_drop_ipv4ll_config(Link *link, Network *network);
 int ipv4ll_update_mac(Link *link);
 

src/network/networkd-link.c

@@ -728,11 +728,11 @@ static int link_acquire_dynamic_ipv4_conf(Link *link) {
                                 return log_link_warning_errno(link, r, "Could not set IPv4 link-local start address: %m");
                 }
 
-                r = sd_ipv4ll_start(link->ipv4ll);
+                r = ipv4ll_start(link);
                 if (r < 0)
                         return log_link_warning_errno(link, r, "Could not acquire IPv4 link-local address: %m");
-
-                log_link_debug(link, "Acquiring IPv4 link-local address.");
+                if (r > 0)
+                        log_link_debug(link, "Acquiring IPv4 link-local address.");
         }
 
         r = link_start_dhcp4_server(link);