daemon: updates to support configuring and tracking mtu, along with over refactoring

daemon/core/emulator/distributed.py

@@ -196,10 +196,10 @@ class DistributedController:
                 continue
             for name in self.servers:
                 server = self.servers[name]
-                self.create_gre_tunnel(node, server, mtu)
+                self.create_gre_tunnel(node, server, mtu, True)
 
     def create_gre_tunnel(
-        self, node: CoreNetwork, server: DistributedServer, mtu: int
+        self, node: CoreNetwork, server: DistributedServer, mtu: int, start: bool
     ) -> Tuple[GreTap, GreTap]:
         """
         Create gre tunnel using a pair of gre taps between the local and remote server.
@@ -207,6 +207,7 @@ class DistributedController:
         :param node: node to create gre tunnel for
         :param server: server to create tunnel for
         :param mtu: mtu for gre taps
+        :param start: True to start gre taps, False otherwise
         :return: local and remote gre taps created for tunnel
         """
         host = server.host
@@ -216,16 +217,18 @@ class DistributedController:
             return tunnel
         # local to server
         logger.info("local tunnel node(%s) to remote(%s) key(%s)", node.name, host, key)
-        local_tap = GreTap(session=self.session, remoteip=host, key=key, mtu=mtu)
-        local_tap.net_client.set_iface_master(node.brname, local_tap.localname)
+        local_tap = GreTap(self.session, host, key=key, mtu=mtu)
+        if start:
+            local_tap.startup()
+            local_tap.net_client.set_iface_master(node.brname, local_tap.localname)
         # server to local
         logger.info(
             "remote tunnel node(%s) to local(%s) key(%s)", node.name, self.address, key
         )
-        remote_tap = GreTap(
-            session=self.session, remoteip=self.address, key=key, server=server, mtu=mtu
-        )
-        remote_tap.net_client.set_iface_master(node.brname, remote_tap.localname)
+        remote_tap = GreTap(self.session, self.address, key=key, server=server, mtu=mtu)
+        if start:
+            remote_tap.startup()
+            remote_tap.net_client.set_iface_master(node.brname, remote_tap.localname)
         # save tunnels for shutdown
         tunnel = (local_tap, remote_tap)
         self.tunnels[key] = tunnel

daemon/core/emulator/session.py

@@ -1496,6 +1496,7 @@ class Session:
                 mac=utils.random_mac(),
                 ip4=ip4,
                 ip4_mask=ip4_mask,
+                mtu=DEFAULT_MTU,
             )
             iface = node.new_iface(control_net, iface_data)
             iface.control = True