Use pytap3 to provide cross-platform IP tunnelling

.github/copilot-instructions.md

@@ -194,7 +194,7 @@ The CLI is in `meshtastic/__main__.py`. When adding new CLI commands:
 
 ### Optional (extras)
 - `cli` extra: `pyqrcode`, `print-color`, `dotmap`, `argcomplete`
-- `tunnel` extra: `pytap2`
+- `tunnel` extra: `pytap3`
 - `analysis` extra: `dash`, `pandas`
 
 ## Important Notes

meshtastic/__main__.py

@@ -1165,8 +1165,7 @@ def setSimpleConfig(modem_preset):
         if args.listen:
             closeNow = False
 
-        have_tunnel = platform.system() == "Linux"
-        if have_tunnel and args.tunnel:
+        if args.tunnel:
             if args.dest != BROADCAST_ADDR:
                 print("A tunnel can only be created using the local node.")
                 return
@@ -1790,11 +1789,10 @@ def common():
             # We assume client is fully connected now
             onConnected(client)
 
-            have_tunnel = platform.system() == "Linux"
             if (
                 args.noproto
                 or args.reply
-                or (have_tunnel and args.tunnel)
+                or args.tunnel
                 or args.listen
             ):  # loop until someone presses ctrlc
                 try:
@@ -2581,22 +2579,20 @@ def initParser():
         "--gpio-watch", help="Start watching a GPIO mask for changes (ex: '0x10')"
     )
 
-    have_tunnel = platform.system() == "Linux"
-    if have_tunnel:
-        tunnelArgs = parser.add_argument_group(
-            "Tunnel", "Arguments related to establishing a tunnel device over the mesh."
-        )
-        tunnelArgs.add_argument(
-            "--tunnel",
-            action="store_true",
-            help="Create a TUN tunnel device for forwarding IP packets over the mesh",
-        )
-        tunnelArgs.add_argument(
-            "--subnet",
-            dest="tunnel_net",
-            help="Sets the local-end subnet address for the TUN IP bridge. (ex: 10.115' which is the default)",
-            default=None,
-        )
+    tunnelArgs = parser.add_argument_group(
+        "Tunnel", "Arguments related to establishing a tunnel device over the mesh."
+    )
+    tunnelArgs.add_argument(
+        "--tunnel",
+        action="store_true",
+        help="Create a TUN tunnel device for forwarding IP packets over the mesh",
+    )
+    tunnelArgs.add_argument(
+        "--subnet",
+        dest="tunnel_net",
+        help="Sets the local-end subnet address for the TUN IP bridge. (ex: 10.115' which is the default)",
+        default=None,
+    )
 
     parser.set_defaults(deprecated=None)
 

meshtastic/tests/test_tunnel.py

@@ -10,27 +10,12 @@
 
 from ..tcp_interface import TCPInterface
 try:
-    # Depends upon pytap2, not installed by default
+    # Depends upon pytap3, not installed by default
     from ..tunnel import Tunnel, onTunnelReceive
 except ImportError:
     pytest.skip("Can't import Tunnel or onTunnelReceive", allow_module_level=True)
 
 
-@pytest.mark.unit
-@patch("platform.system")
-def test_Tunnel_on_non_linux_system(mock_platform_system):
-    """Test that we cannot instantiate a Tunnel on a non Linux system"""
-    a_mock = MagicMock()
-    a_mock.return_value = "notLinux"
-    mock_platform_system.side_effect = a_mock
-    with patch("socket.socket") as mock_socket:
-        with pytest.raises(Tunnel.TunnelError) as pytest_wrapped_e:
-            iface = TCPInterface(hostname="localhost", noProto=True)
-            Tunnel(iface)
-        assert pytest_wrapped_e.type == Tunnel.TunnelError
-        assert mock_socket.called
-
-
 @pytest.mark.unit
 @patch("platform.system")
 def test_Tunnel_without_interface(mock_platform_system):

meshtastic/tunnel.py

@@ -1,7 +1,7 @@
 """Code for IP tunnel over a mesh
 
 # Note python-pytuntap was too buggy
-# using pip3 install pytap2
+# using pip3 install pytap3
 # make sure to "sudo setcap cap_net_admin+eip /usr/bin/python3.8" so python can access tun device without being root
 # sudo ip tuntap del mode tun tun0
 # sudo bin/run.sh --port /dev/ttyUSB0 --setch-shortfast
@@ -20,7 +20,7 @@
 import threading
 
 from pubsub import pub # type: ignore[import-untyped]
-from pytap2 import TapDevice
+from pytap3 import TapDevice
 
 from meshtastic.protobuf import portnums_pb2
 from meshtastic import mt_config
@@ -64,9 +64,6 @@ def __init__(self, iface, subnet: str="10.115", netmask: str="255.255.0.0") -> N
         self.iface = iface
         self.subnetPrefix = subnet
 
-        if platform.system() != "Linux":
-            raise Tunnel.TunnelError("Tunnel() can only be run instantiated on a Linux system")
-
         mt_config.tunnelInstance = self
 
         """A list of chatty UDP services we should never accidentally
@@ -109,6 +106,7 @@ def __init__(self, iface, subnet: str="10.115", netmask: str="255.255.0.0") -> N
 
         logger.debug("creating TUN device with MTU=200")
         # FIXME - figure out real max MTU, it should be 240 - the overhead bytes for SubPacket and Data
+        # Windows would like an MTU >= 576 bytes, but in practice the tunnel works without issues.
         self.tun = None
         if self.iface.noProto:
             logger.warning(