L2CAP: Enhanced Retransmission Mode

examples/run_l2cap_server.py

@@ -0,0 +1,81 @@
+# Copyright 2021-2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# -----------------------------------------------------------------------------
+# Imports
+# -----------------------------------------------------------------------------
+import asyncio
+import sys
+
+from typing import Optional
+
+import bumble.logging
+from bumble.device import Device
+from bumble import l2cap
+from bumble.transport import open_transport
+
+
+# -----------------------------------------------------------------------------
+async def main() -> None:
+
+    print('<<< connecting to HCI...')
+    async with await open_transport(sys.argv[2]) as hci_transport:
+        print('<<< connected')
+
+        # Create a device
+        device = Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
+        device.classic_enabled = True
+        device.l2cap_channel_manager.extended_features.add(
+            l2cap.L2CAP_Information_Request.ExtendedFeatures.ENHANCED_RETRANSMISSION_MODE
+        )
+
+        # Start the controller
+        await device.power_on()
+
+        # Start being discoverable and connectable
+        await device.set_discoverable(True)
+        await device.set_connectable(True)
+
+        channels: list[l2cap.ClassicChannel] = []
+
+        def on_connection(channel: l2cap.ClassicChannel):
+
+            def on_sdu(sdu: bytes):
+                print(f'<<< {sdu.decode()}')
+
+            channel.sink = on_sdu
+            if channels:
+                channels.clear()
+            channels.append(channel)
+
+        server = device.create_l2cap_server(
+            spec=l2cap.ClassicChannelSpec(
+                mode=l2cap.TransmissionMode.ENHANCED_RETRANSMISSION
+            ),
+            handler=on_connection,
+        )
+        print(f'Listen L2CAP on channel {server.psm}')
+
+        while sdu := await asyncio.to_thread(lambda: input('>>> ')):
+            if channels:
+                channels[0].write(sdu.encode())
+
+        await hci_transport.source.terminated
+
+
+# -----------------------------------------------------------------------------
+bumble.logging.setup_basic_logging('INFO')
+asyncio.run(main())