reorder the order of printing

Some USB device properties are only accessible if the user has the
appropriate permissions. Handle libusb1 errors to graciously skip
showing details for these devices.

apps/usb_probe.py

@@ -28,6 +28,7 @@
 # -----------------------------------------------------------------------------
 import os
 import logging
+import sys
 import usb1
 from colors import color
 
@@ -35,6 +36,7 @@ from colors import color
 # -----------------------------------------------------------------------------
 # Constants
 # -----------------------------------------------------------------------------
+USB_DEVICE_CLASS_DEVICE                          = 0x00
 USB_DEVICE_CLASS_WIRELESS_CONTROLLER             = 0xE0
 USB_DEVICE_SUBCLASS_RF_CONTROLLER                = 0x01
 USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER = 0x01
@@ -75,9 +77,79 @@ USB_DEVICE_CLASSES = {
     0xFF: 'Vendor Specific'
 }
 
+USB_ENDPOINT_IN    = 0x80
+USB_ENDPOINT_TYPES = ['CONTROL', 'ISOCHRONOUS', 'BULK', 'INTERRUPT']
+
+USB_BT_HCI_CLASS_TUPLE = (
+    USB_DEVICE_CLASS_WIRELESS_CONTROLLER,
+    USB_DEVICE_SUBCLASS_RF_CONTROLLER,
+    USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+)
+
 
 # -----------------------------------------------------------------------------
-def main():
+def show_device_details(device):
+    for configuration in device:
+        print(f'  Configuration {configuration.getConfigurationValue()}')
+        for interface in configuration:
+            for setting in interface:
+                alternateSetting = setting.getAlternateSetting()
+                suffix = f'/{alternateSetting}' if interface.getNumSettings() > 1 else ''
+                (class_string, subclass_string) = get_class_info(
+                    setting.getClass(),
+                    setting.getSubClass(),
+                    setting.getProtocol()
+                )
+                details = f'({class_string}, {subclass_string})'
+                print(f'      Interface: {setting.getNumber()}{suffix} {details}')
+                for endpoint in setting:
+                    endpoint_type = USB_ENDPOINT_TYPES[endpoint.getAttributes() & 3]
+                    endpoint_direction = 'OUT' if (endpoint.getAddress() & USB_ENDPOINT_IN == 0) else 'IN'
+                    print(f'        Endpoint 0x{endpoint.getAddress():02X}: {endpoint_type} {endpoint_direction}')
+
+
+# -----------------------------------------------------------------------------
+def get_class_info(cls, subclass, protocol):
+    class_info = USB_DEVICE_CLASSES.get(cls)
+    protocol_string = ''
+    if class_info is None:
+        class_string = f'0x{cls:02X}'
+    else:
+        if type(class_info) is tuple:
+            class_string = class_info[0]
+            subclass_info = class_info[1].get(subclass)
+            if subclass_info:
+                protocol_string = subclass_info.get(protocol)
+                if protocol_string is not None:
+                    protocol_string = f' [{protocol_string}]'
+
+        else:
+            class_string = class_info
+
+    subclass_string = f'{subclass}/{protocol}{protocol_string}'
+
+    return (class_string, subclass_string)
+
+
+# -----------------------------------------------------------------------------
+def is_bluetooth_hci(device):
+    # Check if the device class indicates a match
+    if (device.getDeviceClass(), device.getDeviceSubClass(), device.getDeviceProtocol()) == USB_BT_HCI_CLASS_TUPLE:
+        return True
+
+    # If the device class is 'Device', look for a matching interface
+    if device.getDeviceClass() == USB_DEVICE_CLASS_DEVICE:
+        for configuration in device:
+            for interface in configuration:
+                for setting in interface:
+                    if (setting.getClass(), setting.getSubClass(), setting.getProtocol()) == USB_BT_HCI_CLASS_TUPLE:
+                        return True
+
+    return False
+
+
+# -----------------------------------------------------------------------------
+def main(verbose):
     logging.basicConfig(level = os.environ.get('BUMBLE_LOGLEVEL', 'WARNING').upper())
 
     with usb1.USBContext() as context:
@@ -91,23 +163,28 @@ def main():
 
             device_id = (device.getVendorID(), device.getProductID())
 
-            device_is_bluetooth_hci = (
-                device_class    == USB_DEVICE_CLASS_WIRELESS_CONTROLLER and
-                device_subclass == USB_DEVICE_SUBCLASS_RF_CONTROLLER and
-                device_protocol == USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+            (device_class_string, device_subclass_string) = get_class_info(
+                device_class,
+                device_subclass,
+                device_protocol
             )
 
-            device_class_details = ''
-            device_class_info    = USB_DEVICE_CLASSES.get(device_class)
-            if device_class_info is not None:
-                if type(device_class_info) is tuple:
-                    device_class = device_class_info[0]
-                    device_subclass_info = device_class_info[1].get(device_subclass)
-                    if device_subclass_info:
-                        device_class_details = f' [{device_subclass_info.get(device_protocol)}]'
-                else:
-                    device_class = device_class_info
+            try:
+                device_serial_number = device.getSerialNumber()
+            except usb1.USBError:
+                device_serial_number = None
 
+            try:
+                device_manufacturer = device.getManufacturer()
+            except usb1.USBError:
+                device_manufacturer = None
+
+            try:
+                device_product = device.getProduct()
+            except usb1.USBError:
+                device_product = None
+
+            device_is_bluetooth_hci = is_bluetooth_hci(device)
             if device_is_bluetooth_hci:
                 bluetooth_device_count += 1
                 fg_color = 'black'
@@ -123,35 +200,42 @@ def main():
             if device_is_bluetooth_hci:
                 bumble_transport_names.append(f'usb:{bluetooth_device_count - 1}')
 
-            serial_number_collision = False
-            if device_id in devices:
-                for device_serial in devices[device_id]:
-                    if device_serial == device.getSerialNumber():
-                        serial_number_collision = True
-
             if device_id not in devices:
                 bumble_transport_names.append(basic_transport_name)
             else:
                 bumble_transport_names.append(f'{basic_transport_name}#{len(devices[device_id])}')
 
-            if device.getSerialNumber() and not serial_number_collision:
-                bumble_transport_names.append(f'{basic_transport_name}/{device.getSerialNumber()}')
+            if device_serial_number is not None:
+                if device_id not in devices or device_serial_number not in devices[device_id]:
+                    bumble_transport_names.append(f'{basic_transport_name}/{device_serial_number}')
 
+            # Print the results
             print(color(f'ID {device.getVendorID():04X}:{device.getProductID():04X}', fg=fg_color, bg=bg_color))
             if bumble_transport_names:
                 print(color('  Bumble Transport Names:', 'blue'), ' or '.join(color(x, 'cyan' if device_is_bluetooth_hci else 'red') for x in bumble_transport_names))
             print(color('  Bus/Device:            ', 'green'), f'{device.getBusNumber():03}/{device.getDeviceAddress():03}')
-            if device.getSerialNumber():
-                print(color('  Serial:                ', 'green'), device.getSerialNumber())
-            print(color('  Class:                 ', 'green'), device_class)
-            print(color('  Subclass/Protocol:     ', 'green'), f'{device_subclass}/{device_protocol}{device_class_details}')
-            print(color('  Manufacturer:          ', 'green'), device.getManufacturer())
-            print(color('  Product:               ', 'green'), device.getProduct())
+            print(color('  Class:                 ', 'green'), device_class_string)
+            print(color('  Subclass/Protocol:     ', 'green'), device_subclass_string)
+            if device_serial_number is not None:
+                print(color('  Serial:                ', 'green'), device_serial_number)
+            if device_manufacturer is not None:
+                print(color('  Manufacturer:          ', 'green'), device_manufacturer)
+            if device_product is not None:
+                print(color('  Product:               ', 'green'), device_product)
+
+            if verbose:
+                show_device_details(device)
+
             print()
 
-            devices.setdefault(device_id, []).append(device.getSerialNumber())
+            devices.setdefault(device_id, []).append(device_serial_number)
 
 
 # -----------------------------------------------------------------------------
 if __name__ == '__main__':
-    main()
+    if len(sys.argv) == 2 and sys.argv[1] == '--verbose':
+        verbose = True
+    else:
+        verbose = False
+
+    main(verbose)

bumble/helpers.py

@@ -18,6 +18,8 @@
 import logging
 from colors import color
 
+from bumble.smp import SMP_CID, SMP_Command
+
 from .core import name_or_number
 from .gatt import ATT_PDU, ATT_CID
 from .l2cap import (
@@ -73,6 +75,9 @@ class PacketTracer:
             if l2cap_pdu.cid == ATT_CID:
                 att_pdu = ATT_PDU.from_bytes(l2cap_pdu.payload)
                 self.analyzer.emit(att_pdu)
+            elif l2cap_pdu.cid == SMP_CID:
+                smp_command = SMP_Command.from_bytes(l2cap_pdu.payload)
+                self.analyzer.emit(smp_command)
             elif l2cap_pdu.cid == L2CAP_SIGNALING_CID or l2cap_pdu.cid == L2CAP_LE_SIGNALING_CID:
                 control_frame = L2CAP_Control_Frame.from_bytes(l2cap_pdu.payload)
                 self.analyzer.emit(control_frame)

bumble/smp.py

@@ -155,6 +155,7 @@ SMP_CT2_AUTHREQ      = 0b00100000
 SMP_CTKD_H7_LEBR_SALT = bytes.fromhex('00000000000000000000000000000000746D7031')
 SMP_CTKD_H7_BRLE_SALT = bytes.fromhex('00000000000000000000000000000000746D7032')
 
+
 # -----------------------------------------------------------------------------
 # Utils
 # -----------------------------------------------------------------------------
@@ -879,7 +880,7 @@ class Session:
                 )
             )
         )
-    
+
     async def derive_ltk(self):
         link_key = await self.manager.device.get_link_key(self.connection.peer_address)
         assert link_key is not None
@@ -914,7 +915,7 @@ class Session:
             csrk = bytes(16)  # FIXME: testing
             if self.initiator_key_distribution & SMP_SIGN_KEY_DISTRIBUTION_FLAG:
                 self.send_command(SMP_Signing_Information_Command(signature_key=csrk))
-            
+
             # CTKD, calculate BR/EDR link key
             if self.initiator_key_distribution & SMP_LINK_KEY_DISTRIBUTION_FLAG:
                 ilk = crypto.h7(
@@ -946,7 +947,7 @@ class Session:
             csrk = bytes(16)  # FIXME: testing
             if self.responder_key_distribution & SMP_SIGN_KEY_DISTRIBUTION_FLAG:
                 self.send_command(SMP_Signing_Information_Command(signature_key=csrk))
-            
+
             # CTKD, calculate BR/EDR link key
             if self.responder_key_distribution & SMP_LINK_KEY_DISTRIBUTION_FLAG:
                 ilk = crypto.h7(
@@ -980,12 +981,7 @@ class Session:
             self.peer_expected_distributions.remove(command_class)
             logger.debug(f'remaining distributions: {[c.__name__ for c in self.peer_expected_distributions]}')
             if not self.peer_expected_distributions:
-                # The initiator can now send its keys
-                if self.is_initiator:
-                    self.distribute_keys()
-
-                # Nothing left to expect, we're done
-                asyncio.create_task(self.on_pairing())
+                self.on_peer_key_distribution_complete()
         else:
             logger.warn(color(f'!!! unexpected key distribution command: {command_class.__name__}', 'red'))
             self.send_pairing_failed(SMP_UNSPECIFIED_REASON_ERROR)
@@ -1006,12 +1002,23 @@ class Session:
         self.connection.remove_listener('connection_encryption_key_refresh', self.on_connection_encryption_key_refresh)
         self.manager.on_session_end(self)
 
+    def on_peer_key_distribution_complete(self):
+        # The initiator can now send its keys
+        if self.is_initiator:
+            self.distribute_keys()
+
+        asyncio.create_task(self.on_pairing())
+
     def on_connection_encryption_change(self):
         if self.connection.is_encrypted:
             if self.is_responder:
                 # The responder distributes its keys first, the initiator later
                 self.distribute_keys()
 
+            # If we're not expecting key distributions from the peer, we're done
+            if not self.peer_expected_distributions:
+                self.on_peer_key_distribution_complete()
+
     def on_connection_encryption_key_refresh(self):
         # Do as if the connection had just been encrypted
         self.on_connection_encryption_change()

bumble/transport/usb.py

@@ -36,7 +36,7 @@ logger = logging.getLogger(__name__)
 async def open_usb_transport(spec):
     '''
     Open a USB transport.
-    The parameter string has this syntax:
+    The moniker string has this syntax:
     either <index> or
     <vendor>:<product> or
     <vendor>:<product>/<serial-number>] or
@@ -47,27 +47,40 @@ async def open_usb_transport(spec):
     /<serial-number> suffix or #<index> suffix max be specified when more than one device with
     the same vendor and product identifiers are present.
 
+    In addition, if the moniker ends with the symbol "!", the device will be used in "forced" mode:
+    the first USB interface of the device will be used, regardless of the interface class/subclass.
+    This may be useful for some devices that use a custom class/subclass but may nonetheless work as-is.
+
     Examples:
     0 --> the first BT USB dongle
     04b4:f901 --> the BT USB dongle with vendor=04b4 and product=f901
     04b4:f901#2 --> the third USB device with vendor=04b4 and product=f901
     04b4:f901/00E04C239987 --> the BT USB dongle with vendor=04b4 and product=f901 and serial number 00E04C239987
+    usb:0B05:17CB! --> the BT USB dongle vendor=0B05 and product=17CB, in "forced" mode.
     '''
 
     USB_RECIPIENT_DEVICE                             = 0x00
     USB_REQUEST_TYPE_CLASS                           = 0x01 << 5
-    USB_ENDPOINT_EVENTS_IN                           = 0x81
-    USB_ENDPOINT_ACL_IN                              = 0x82
-    USB_ENDPOINT_ACL_OUT                             = 0x02
+    USB_DEVICE_CLASS_DEVICE                          = 0x00
     USB_DEVICE_CLASS_WIRELESS_CONTROLLER             = 0xE0
     USB_DEVICE_SUBCLASS_RF_CONTROLLER                = 0x01
     USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER = 0x01
+    USB_ENDPOINT_TRANSFER_TYPE_BULK                  = 0x02
+    USB_ENDPOINT_TRANSFER_TYPE_INTERRUPT             = 0x03
+    USB_ENDPOINT_IN                                  = 0x80
+
+    USB_BT_HCI_CLASS_TUPLE = (
+        USB_DEVICE_CLASS_WIRELESS_CONTROLLER,
+        USB_DEVICE_SUBCLASS_RF_CONTROLLER,
+        USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
+    )
 
     READ_SIZE = 1024
 
     class UsbPacketSink:
-        def __init__(self, device):
+        def __init__(self, device, acl_out):
             self.device      = device
+            self.acl_out     = acl_out
             self.transfer    = device.getTransfer()
             self.packets     = collections.deque()  # Queue of packets waiting to be sent
             self.loop        = asyncio.get_running_loop()
@@ -116,7 +129,7 @@ async def open_usb_transport(spec):
             packet_type = packet[0]
             if packet_type == hci.HCI_ACL_DATA_PACKET:
                 self.transfer.setBulk(
-                    USB_ENDPOINT_ACL_OUT,
+                    self.acl_out,
                     packet[1:],
                     callback=self.on_packet_sent
                 )
@@ -152,10 +165,12 @@ async def open_usb_transport(spec):
                     logger.debug('OUT transfer likely already completed')
 
     class UsbPacketSource(asyncio.Protocol, ParserSource):
-        def __init__(self, context, device):
+        def __init__(self, context, device, acl_in, events_in):
             super().__init__()
             self.context         = context
             self.device          = device
+            self.acl_in          = acl_in
+            self.events_in       = events_in
             self.loop            = asyncio.get_running_loop()
             self.queue           = asyncio.Queue()
             self.closed          = False
@@ -172,7 +187,7 @@ async def open_usb_transport(spec):
             # Set up transfer objects for input
             self.events_in_transfer = device.getTransfer()
             self.events_in_transfer.setInterrupt(
-                USB_ENDPOINT_EVENTS_IN,
+                self.events_in,
                 READ_SIZE,
                 callback=self.on_packet_received,
                 user_data=hci.HCI_EVENT_PACKET
@@ -181,7 +196,7 @@ async def open_usb_transport(spec):
 
             self.acl_in_transfer = device.getTransfer()
             self.acl_in_transfer.setBulk(
-                USB_ENDPOINT_ACL_IN,
+                self.acl_in,
                 READ_SIZE,
                 callback=self.on_packet_received,
                 user_data=hci.HCI_ACL_DATA_PACKET
@@ -248,7 +263,7 @@ async def open_usb_transport(spec):
             await self.event_loop_done
 
     class UsbTransport(Transport):
-        def __init__(self, context, device, interface, source, sink):
+        def __init__(self, context, device, interface, setting, source, sink):
             super().__init__(source, sink)
             self.context   = context
             self.device    = device
@@ -257,6 +272,10 @@ async def open_usb_transport(spec):
             # Get exclusive access
             device.claimInterface(interface)
 
+            # Set the alternate setting if not the default
+            if setting != 0:
+                device.setInterfaceAltSetting(interface, setting)
+
             # The source and sink can now start
             source.start()
             sink.start()
@@ -273,6 +292,13 @@ async def open_usb_transport(spec):
     context.open()
     try:
         found = None
+
+        if spec.endswith('!'):
+            spec = spec[:-1]
+            forced_mode = True
+        else:
+            forced_mode = False
+
         if ':' in spec:
             vendor_id, product_id = spec.split(':')
             serial_number = None
@@ -284,10 +310,14 @@ async def open_usb_transport(spec):
                 device_index = int(device_index_str)
 
             for device in context.getDeviceIterator(skip_on_error=True):
+                try:
+                    device_serial_number = device.getSerialNumber()
+                except usb1.USBError:
+                    device_serial_number = None
                 if (
                     device.getVendorID() == int(vendor_id, 16) and
                     device.getProductID() == int(product_id, 16) and
-                    (serial_number is None or device.getSerialNumber() == serial_number)
+                    (serial_number is None or serial_number == device_serial_number)
                 ):
                     if device_index == 0:
                         found = device
@@ -295,13 +325,27 @@ async def open_usb_transport(spec):
                     device_index -= 1
                 device.close()
         else:
+            # Look for a compatible device by index
+            def device_is_bluetooth_hci(device):
+                # Check if the device class indicates a match
+                if (device.getDeviceClass(), device.getDeviceSubClass(), device.getDeviceProtocol()) == \
+                        USB_BT_HCI_CLASS_TUPLE:
+                    return True
+
+                # If the device class is 'Device', look for a matching interface
+                if device.getDeviceClass() == USB_DEVICE_CLASS_DEVICE:
+                    for configuration in device:
+                        for interface in configuration:
+                            for setting in interface:
+                                if (setting.getClass(), setting.getSubClass(), setting.getProtocol()) == \
+                                        USB_BT_HCI_CLASS_TUPLE:
+                                    return True
+
+                return False
+
             device_index = int(spec)
             for device in context.getDeviceIterator(skip_on_error=True):
-                if (
-                    device.getDeviceClass()    == USB_DEVICE_CLASS_WIRELESS_CONTROLLER and
-                    device.getDeviceSubClass() == USB_DEVICE_SUBCLASS_RF_CONTROLLER and
-                    device.getDeviceProtocol() == USB_DEVICE_PROTOCOL_BLUETOOTH_PRIMARY_CONTROLLER
-                ):
+                if device_is_bluetooth_hci(device):
                     if device_index == 0:
                         found = device
                         break
@@ -313,10 +357,62 @@ async def open_usb_transport(spec):
             raise ValueError('device not found')
 
         logger.debug(f'USB Device: {found}')
-        device = found.open()
 
-        # Use the first interface
-        interface = 0
+        # Look for the first interface with the right class and endpoints
+        def find_endpoints(device):
+            for (configuration_index, configuration) in enumerate(device):
+                interface = None
+                for interface in configuration:
+                    setting = None
+                    for setting in interface:
+                        if (
+                            not forced_mode and
+                            (setting.getClass(), setting.getSubClass(), setting.getProtocol()) != USB_BT_HCI_CLASS_TUPLE
+                        ):
+                            continue
+
+                        events_in = None
+                        acl_in    = None
+                        acl_out   = None
+                        for endpoint in setting:
+                            attributes = endpoint.getAttributes()
+                            address    = endpoint.getAddress()
+                            if attributes & 0x03 == USB_ENDPOINT_TRANSFER_TYPE_BULK:
+                                if address & USB_ENDPOINT_IN and acl_in is None:
+                                    acl_in = address
+                                elif acl_out is None:
+                                    acl_out = address
+                            elif attributes & 0x03 == USB_ENDPOINT_TRANSFER_TYPE_INTERRUPT:
+                                if address & USB_ENDPOINT_IN and events_in is None:
+                                    events_in = address
+
+                        # Return if we found all 3 endpoints
+                        if acl_in is not None and acl_out is not None and events_in is not None:
+                            return (
+                                configuration_index + 1,
+                                setting.getNumber(),
+                                setting.getAlternateSetting(),
+                                acl_in,
+                                acl_out,
+                                events_in
+                            )
+                        else:
+                            logger.debug(f'skipping configuration {configuration_index + 1} / interface {setting.getNumber()}')
+
+        endpoints = find_endpoints(found)
+        if endpoints is None:
+            raise ValueError('no compatible interface found for device')
+        (configuration, interface, setting, acl_in, acl_out, events_in) = endpoints
+        logger.debug(
+            f'selected endpoints: configuration={configuration}, '
+            f'interface={interface}, '
+            f'setting={setting}, '
+            f'acl_in=0x{acl_in:02X}, '
+            f'acl_out=0x{acl_out:02X}, '
+            f'events_in=0x{events_in:02X}, '
+        )
+
+        device = found.open()
 
         # Detach the kernel driver if supported and needed
         if usb1.hasCapability(usb1.CAP_SUPPORTS_DETACH_KERNEL_DRIVER):
@@ -329,21 +425,21 @@ async def open_usb_transport(spec):
 
         # Set the configuration if needed
         try:
-            configuration = device.getConfiguration()
-            logger.debug(f'current configuration = {configuration}')
+            current_configuration = device.getConfiguration()
+            logger.debug(f'current configuration = {current_configuration}')
         except usb1.USBError:
-            configuration = 0
+            current_configuration = 0
 
-        if configuration != 1:
+        if current_configuration != configuration:
             try:
-                logger.debug('setting configuration 1')
-                device.setConfiguration(1)
+                logger.debug(f'setting configuration {configuration}')
+                device.setConfiguration(configuration)
             except usb1.USBError:
-                logger.warning('failed to set configuration 1')
+                logger.warning('failed to set configuration')
 
-        source = UsbPacketSource(context, device)
-        sink   = UsbPacketSink(device)
-        return UsbTransport(context, device, interface, source, sink)
+        source = UsbPacketSource(context, device, acl_in, events_in)
+        sink   = UsbPacketSink(device, acl_out)
+        return UsbTransport(context, device, interface, setting, source, sink)
     except usb1.USBError as error:
         logger.warning(color(f'!!! failed to open USB device: {error}', 'red'))
         context.close()

docs/mkdocs/mkdocs.yml

@@ -45,6 +45,10 @@ nav:
     - HCI Bridge: apps_and_tools/hci_bridge.md
     - Golden Gate Bridge: apps_and_tools/gg_bridge.md
     - Show: apps_and_tools/show.md
+    - GATT Dump: apps_and_tools/gatt_dump.md
+    - Pair: apps_and_tools/pair.md
+    - Unbond: apps_and_tools/unbond.md
+    - USB Probe: apps_and_tools/usb_probe.md
   - Hardware:
     - Overview: hardware/index.md
   - Platforms:

docs/mkdocs/src/apps_and_tools/usb_probe.md

@@ -13,17 +13,29 @@ type of device (there's no way to tell).
 
 ## Usage
 
-This command line tool takes no arguments.
+This command line tool may be invoked with no arguments, or with `--verbose`
+for extra details.
 When installed from PyPI, run as
 ```
 $ bumble-usb-probe
 ```
 
+or, for extra details, with the `--verbose` argument
+```
+$ bumble-usb-probe --v
+```
+
 When running from the source distribution:
 ```
 $ python3 apps/usb-probe.py
 ```
 
+or 
+
+```
+$ python3 apps/usb-probe.py --verbose
+```
+
 !!! example
     ```
     $ python3 apps/usb_probe.py 

docs/mkdocs/src/transports/usb.md

@@ -5,6 +5,7 @@ The USB transport interfaces with a local Bluetooth USB dongle.
 
 ## Moniker
 The moniker for a USB transport is either:
+
   * `usb:<index>`
   * `usb:<vendor>:<product>`
   * `usb:<vendor>:<product>/<serial-number>`
@@ -16,6 +17,10 @@ In the `usb:<vendor>:<product>#<index>` form, matching devices are the ones with
 
 `<vendor>` and `<product>` are a vendor ID and product ID in hexadecimal.
 
+In addition, if the moniker ends with the symbol "!", the device will be used in "forced" mode:
+the first USB interface of the device will be used, regardless of the interface class/subclass.
+This may be useful for some devices that use a custom class/subclass but may nonetheless work as-is.
+
 !!! examples
     `usb:04b4:f901`  
     The USB dongle with `<vendor>` equal to `04b4` and `<product>` equal to `f901`
@@ -29,6 +34,10 @@ In the `usb:<vendor>:<product>#<index>` form, matching devices are the ones with
     `usb:04b4:f901/#1`
     The second USB dongle with `<vendor>` equal to `04b4` and `<product>` equal to `f901`
 
+    `usb:0B05:17CB!`
+    The BT USB dongle vendor=0B05 and product=17CB, in "forced" mode.
+
+
 ## Alternative
 The library includes two different implementations of the USB transport, implemented using different python bindings for `libusb`.
 Using the transport prefix `pyusb:` instead of `usb:` selects the implementation based on  [PyUSB](https://pypi.org/project/pyusb/), using the synchronous API of `libusb`, whereas the default implementation is based on [libusb1](https://pypi.org/project/libusb1/), using the asynchronous API of `libusb`. In order to use the alternative PyUSB-based implementation, you need to ensure that you have installed that python module, as it isn't installed by default as a dependency of Bumble.

tests/self_test.py

@@ -246,8 +246,7 @@ IO_CAP = [
 SC = [False, True]
 MITM = [False, True]
 # Key distribution is a 4-bit bitmask
-# IdKey is necessary for current SMP structure
-KEY_DIST = [i for i in range(16) if (i & SMP_ID_KEY_DISTRIBUTION_FLAG)]
+KEY_DIST = range(16)
 
 @pytest.mark.asyncio
 @pytest.mark.parametrize('io_cap, sc, mitm, key_dist',