networkd: vlan add GVRP support (#5761)

Add support to configure GVRP.

Closes #5760

src/network/netdev/vlan.c

@@ -17,12 +17,14 @@
   along with systemd; If not, see <http://www.gnu.org/licenses/>.
 ***/
 
+#include <linux/if_vlan.h>
 #include <net/if.h>
 
 #include "netdev/vlan.h"
 #include "vlan-util.h"
 
 static int netdev_vlan_fill_message_create(NetDev *netdev, Link *link, sd_netlink_message *req) {
+        struct ifla_vlan_flags flags = {};
         VLan *v;
         int r;
 
@@ -38,6 +40,19 @@ static int netdev_vlan_fill_message_create(NetDev *netdev, Link *link, sd_netlin
         if (r < 0)
                 return log_netdev_error_errno(netdev, r, "Could not append IFLA_VLAN_ID attribute: %m");
 
+        if (v->gvrp != -1) {
+                flags.mask |= VLAN_FLAG_GVRP;
+
+                if (v->gvrp)
+                        flags.flags |= VLAN_FLAG_GVRP;
+                else
+                        flags.flags &= ~VLAN_FLAG_GVRP;
+        }
+
+        r = sd_netlink_message_append_data(req, IFLA_VLAN_FLAGS, &flags, sizeof(struct ifla_vlan_flags));
+        if (r < 0)
+                return log_netdev_error_errno(netdev, r, "Could not append IFLA_VLAN_FLAGS attribute: %m");
+
         return 0;
 }
 
@@ -66,6 +81,7 @@ static void vlan_init(NetDev *netdev) {
         assert(v);
 
         v->id = VLANID_INVALID;
+        v->gvrp = -1;
 }
 
 const NetDevVTable vlan_vtable = {