Merge pull request #29544 from yuwata/network-dhcp-bus-command

network: several fixlets for DBus methods for DHCP client and server

src/libsystemd-network/sd-dhcp-server.c

@@ -113,7 +113,8 @@ int sd_dhcp_server_configure_pool(
 }
 
 int sd_dhcp_server_is_running(sd_dhcp_server *server) {
-        assert_return(server, false);
+        if (!server)
+                return false;
 
         return !!server->receive_message;
 }

src/network/networkd-link-bus.c

@@ -599,7 +599,7 @@ int bus_link_method_force_renew(sd_bus_message *message, void *userdata, sd_bus_
         if (r == 0)
                 return 1; /* Polkit will call us back */
 
-        if (l->dhcp_server) {
+        if (sd_dhcp_server_is_running(l->dhcp_server)) {
                 r = sd_dhcp_server_forcerenew(l->dhcp_server);
                 if (r < 0)
                         return r;
@@ -626,11 +626,15 @@ int bus_link_method_renew(sd_bus_message *message, void *userdata, sd_bus_error
         if (r == 0)
                 return 1; /* Polkit will call us back */
 
-        if (l->dhcp_client) {
+        if (sd_dhcp_client_is_running(l->dhcp_client))
                 r = sd_dhcp_client_send_renew(l->dhcp_client);
-                if (r < 0)
+        else
-                        return r;
+                /* The DHCPv4 client may have been stopped by the IPv6 only mode. Let's unconditionally
-        }
+                 * restart the client here. Note, if the DHCPv4 client is disabled, then dhcp4_start() does
+                 * nothing and returns 0. */
+                r = dhcp4_start(l);
+        if (r < 0)
+                return r;
 
         return sd_bus_reply_method_return(message, NULL);
 }

test/test-network/systemd-networkd-tests.py

@@ -5271,6 +5271,31 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
         print(f"DHCPv4 client state = {state}")
         self.assertEqual(state, 'stopped')
 
+        # restart dnsmasq to clear log
+        stop_dnsmasq()
+        start_dnsmasq('--dhcp-option=108,00:00:02:00')
+
+        # Test renew command
+        # See https://github.com/systemd/systemd/pull/29472#issuecomment-1759092138
+        check_output(*networkctl_cmd, 'renew', 'veth99', env=env)
+
+        for _ in range(100):
+            state = get_dhcp4_client_state('veth99')
+            if state == 'stopped':
+                break
+            time.sleep(.2)
+
+        print(f"DHCPv4 client state = {state}")
+        self.assertEqual(state, 'stopped')
+
+        print('## dnsmasq log')
+        output = read_dnsmasq_log_file()
+        print(output)
+        self.assertIn('DHCPDISCOVER(veth-peer) 12:34:56:78:9a:bc', output)
+        self.assertIn('DHCPOFFER(veth-peer)', output)
+        self.assertNotIn('DHCPREQUEST(veth-peer)', output)
+        self.assertNotIn('DHCPACK(veth-peer)', output)
+
     def test_dhcp_client_ipv6_only_with_custom_client_identifier(self):
         copy_network_unit('25-veth.netdev', '25-dhcp-server-veth-peer.network', '25-dhcp-client-ipv6-only-custom-client-identifier.network')
 
@@ -5294,8 +5319,6 @@ class NetworkdDHCPClientTests(unittest.TestCase, Utilities):
         self.assertIn('DHCPREPLY(veth-peer)', output)
         self.assertIn('sent size:  0 option: 14 rapid-commit', output)
 
-        stop_dnsmasq()
-
     def test_dhcp_client_ipv4_only(self):
         copy_network_unit('25-veth.netdev', '25-dhcp-server-veth-peer.network', '25-dhcp-client-ipv4-only.network')