libsystemd-network: do not request each daemon exist in sd_xxx_stop()

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

@@ -2135,9 +2135,10 @@ int sd_dhcp_client_send_decline(sd_dhcp_client *client) {
 }
 
 int sd_dhcp_client_stop(sd_dhcp_client *client) {
-        DHCP_CLIENT_DONT_DESTROY(client);
+        if (!client)
+                return 0;
 
-        assert_return(client, -EINVAL);
+        DHCP_CLIENT_DONT_DESTROY(client);
 
         client_stop(client, SD_DHCP_CLIENT_EVENT_STOP);
         client->state = DHCP_STATE_STOPPED;

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

@@ -225,7 +225,8 @@ sd_event *sd_dhcp_server_get_event(sd_dhcp_server *server) {
 }
 
 int sd_dhcp_server_stop(sd_dhcp_server *server) {
-        assert_return(server, -EINVAL);
+        if (!server)
+                return 0;
 
         server->receive_message =
                 sd_event_source_unref(server->receive_message);

src/libsystemd-network/sd-dhcp6-client.c

@@ -1676,7 +1676,8 @@ static int client_start(sd_dhcp6_client *client, enum DHCP6State state) {
 }
 
 int sd_dhcp6_client_stop(sd_dhcp6_client *client) {
-        assert_return(client, -EINVAL);
+        if (!client)
+                return 0;
 
         client_stop(client, SD_DHCP6_CLIENT_EVENT_STOP);
 

src/libsystemd-network/sd-ipv4acd.c

@@ -144,7 +144,8 @@ static void ipv4acd_client_notify(sd_ipv4acd *acd, int event) {
 int sd_ipv4acd_stop(sd_ipv4acd *acd) {
         IPv4ACDState old_state;
 
-        assert_return(acd, -EINVAL);
+        if (!acd)
+                return 0;
 
         old_state = acd->state;
 

src/libsystemd-network/sd-ipv4ll.c

@@ -89,7 +89,8 @@ int sd_ipv4ll_new(sd_ipv4ll **ret) {
 }
 
 int sd_ipv4ll_stop(sd_ipv4ll *ll) {
-        assert_return(ll, -EINVAL);
+        if (!ll)
+                return 0;
 
         return sd_ipv4acd_stop(ll->acd);
 }

src/libsystemd-network/sd-lldp.c

@@ -276,7 +276,8 @@ fail:
 }
 
 _public_ int sd_lldp_stop(sd_lldp *lldp) {
-        assert_return(lldp, -EINVAL);
+        if (!lldp)
+                return 0;
 
         if (lldp->fd < 0)
                 return 0;

src/libsystemd-network/sd-ndisc.c

@@ -321,7 +321,8 @@ static int ndisc_timeout_no_ra(sd_event_source *s, uint64_t usec, void *userdata
 }
 
 _public_ int sd_ndisc_stop(sd_ndisc *nd) {
-        assert_return(nd, -EINVAL);
+        if (!nd)
+                return 0;
 
         if (nd->fd < 0)
                 return 0;

src/libsystemd-network/sd-radv.c

@@ -353,7 +353,8 @@ fail:
 _public_ int sd_radv_stop(sd_radv *ra) {
         int r;
 
-        assert_return(ra, -EINVAL);
+        if (!ra)
+                return 0;
 
         if (ra->state == SD_RADV_STATE_IDLE)
                 return 0;