[WIP] L2CAP Enhanced Retransmission mode

bumble/device.py

@@ -2072,6 +2072,10 @@ class DeviceConfiguration:
     io_capability: int = pairing.PairingDelegate.IoCapability.NO_OUTPUT_NO_INPUT
     gap_service_enabled: bool = True
     gatt_service_enabled: bool = True
+    enhanced_retransmission_supported: bool = False
+    l2cap_extended_features: Sequence[int] = (
+        l2cap.L2CAP_Information_Request.ExtendedFeatures.FIXED_CHANNELS,
+    )
 
     def __post_init__(self) -> None:
         self.gatt_services: list[dict[str, Any]] = []
@@ -2341,14 +2345,18 @@ def __init__(
     ) -> None:
         super().__init__()
 
+        # Use the initial config or a default
+        config = config or DeviceConfiguration()
+        self.config = config
+
         self._host = None
         self.powered_on = False
         self.auto_restart_inquiry = True
         self.command_timeout = 10  # seconds
         self.gatt_server = gatt_server.Server(self)
         self.sdp_server = sdp.Server(self)
         self.l2cap_channel_manager = l2cap.ChannelManager(
-            [l2cap.L2CAP_Information_Request.EXTENDED_FEATURE_FIXED_CHANNELS]
+            config.l2cap_extended_features
         )
         self.advertisement_accumulators = {}  # Accumulators, by address
         self.periodic_advertising_syncs = []
@@ -2383,10 +2391,6 @@ def __init__(
         # Own address type cache
         self.connect_own_address_type = None
 
-        # Use the initial config or a default
-        config = config or DeviceConfiguration()
-        self.config = config
-
         self.name = config.name
         self.public_address = hci.Address.ANY
         self.random_address = config.address

bumble/host.py

@@ -707,7 +707,9 @@ async def send_command(command: hci.HCI_Command) -> None:
 
         asyncio.create_task(send_command(command))
 
-    def send_l2cap_pdu(self, connection_handle: int, cid: int, pdu: bytes) -> None:
+    def send_l2cap_pdu(
+        self, connection_handle: int, cid: int, pdu: bytes, with_fcs: bool = False
+    ) -> None:
         if not (connection := self.connections.get(connection_handle)):
             logger.warning(f'connection 0x{connection_handle:04X} not found')
             return
@@ -719,26 +721,23 @@ def send_l2cap_pdu(self, connection_handle: int, cid: int, pdu: bytes) -> None:
             return
 
         # Create a PDU
-        l2cap_pdu = bytes(L2CAP_PDU(cid, pdu))
+        l2cap_pdu = L2CAP_PDU(cid, pdu).to_bytes(with_fcs)
 
         # Send the data to the controller via ACL packets
-        bytes_remaining = len(l2cap_pdu)
-        offset = 0
-        pb_flag = 0
-        while bytes_remaining:
-            data_total_length = min(bytes_remaining, packet_queue.max_packet_size)
+        max_packet_size = packet_queue.max_packet_size
+        for offset in range(0, len(l2cap_pdu), max_packet_size):
+            pdu = l2cap_pdu[offset : offset + max_packet_size]
             acl_packet = hci.HCI_AclDataPacket(
                 connection_handle=connection_handle,
-                pb_flag=pb_flag,
+                pb_flag=1 if offset > 0 else 0,
                 bc_flag=0,
-                data_total_length=data_total_length,
-                data=l2cap_pdu[offset : offset + data_total_length],
+                data_total_length=len(pdu),
+                data=pdu,
+            )
+            logger.debug(
+                '>>> ACL packet enqueue: (Handle=0x%04X) %s', connection_handle, pdu
             )
-            logger.debug(f'>>> ACL packet enqueue: (CID={cid}) {acl_packet}')
             packet_queue.enqueue(acl_packet, connection_handle)
-            pb_flag = 1
-            offset += data_total_length
-            bytes_remaining -= data_total_length
 
     def get_data_packet_queue(self, connection_handle: int) -> DataPacketQueue | None:
         if connection := self.connections.get(connection_handle):