Handle L2CAP info dynamically (#28)

* Add feature and MTU fields in L2CAP manager constructor
* Add register/unregister API for fixed channels

.github/workflows/python-build-test.yml

@@ -29,11 +29,11 @@ jobs:
     - name: Install dependencies
       run: |
         python -m pip install --upgrade pip
-        python -m pip install ".[test,development,documentation]"
+        python -m pip install ".[build,test,development,documentation]"
     - name: Test with pytest
       run: |
         pytest
     - name: Build
       run: |
         inv build
-        inv mkdocs
+        inv build.mkdocs

bumble/device.py

@@ -315,6 +315,8 @@ class DeviceConfiguration:
         self.le_simultaneous_enabled  = True
         self.classic_sc_enabled       = True
         self.classic_ssp_enabled      = True
+        self.connectable              = True
+        self.discoverable             = True
         self.advertising_data = bytes(
             AdvertisingData([(AdvertisingData.COMPLETE_LOCAL_NAME, bytes(self.name, 'utf-8'))])
         )
@@ -333,6 +335,8 @@ class DeviceConfiguration:
         self.le_simultaneous_enabled  = config.get('le_simultaneous_enabled', self.le_simultaneous_enabled)
         self.classic_sc_enabled       = config.get('classic_sc_enabled', self.classic_sc_enabled)
         self.classic_ssp_enabled      = config.get('classic_ssp_enabled', self.classic_ssp_enabled)
+        self.connectable              = config.get('connectable', self.connectable)
+        self.discoverable             = config.get('discoverable', self.discoverable)
 
         # Load or synthesize an IRK
         irk = config.get('irk')
@@ -446,7 +450,8 @@ class Device(CompositeEventEmitter):
         self.command_timeout          = 10  # seconds
         self.gatt_server              = gatt_server.Server(self)
         self.sdp_server               = sdp.Server(self)
-        self.l2cap_channel_manager    = l2cap.ChannelManager()
+        self.l2cap_channel_manager    = l2cap.ChannelManager(
+            [l2cap.L2CAP_Information_Request.EXTENDED_FEATURE_FIXED_CHANNELS])
         self.advertisement_data       = {}
         self.scanning                 = False
         self.discovering              = False
@@ -454,8 +459,6 @@ class Device(CompositeEventEmitter):
         self.disconnecting            = False
         self.connections              = {}  # Connections, by connection handle
         self.classic_enabled          = False
-        self.discoverable             = False
-        self.connectable              = False
         self.inquiry_response         = None
         self.address_resolver         = None
 
@@ -476,6 +479,8 @@ class Device(CompositeEventEmitter):
         self.le_simultaneous_enabled  = config.le_simultaneous_enabled
         self.classic_ssp_enabled      = config.classic_ssp_enabled
         self.classic_sc_enabled       = config.classic_sc_enabled
+        self.discoverable             = config.discoverable
+        self.connectable              = config.connectable
 
         # If a name is passed, override the name from the config
         if name:
@@ -490,6 +495,8 @@ class Device(CompositeEventEmitter):
         # Setup SMP
         # TODO: allow using a public address
         self.smp_manager = smp.Manager(self, self.random_address)
+        self.l2cap_channel_manager.register_fixed_channel(
+            smp.SMP_CID, self.on_smp_pdu)
 
         # Register the SDP server with the L2CAP Channel Manager
         self.sdp_server.register(self.l2cap_channel_manager)
@@ -497,6 +504,7 @@ class Device(CompositeEventEmitter):
         # Add a GAP Service if requested
         if generic_access_service:
             self.gatt_server.add_service(GenericAccessService(self.name))
+        self.l2cap_channel_manager.register_fixed_channel(ATT_CID, self.on_gatt_pdu)
 
         # Forward some events
         setup_event_forwarding(self.gatt_server, self, 'characteristic_subscription')
@@ -623,6 +631,8 @@ class Device(CompositeEventEmitter):
                 HCI_Write_Secure_Connections_Host_Support_Command(
                     secure_connections_host_support=int(self.classic_sc_enabled))
             )
+            await self.set_connectable(self.connectable)
+            await self.set_discoverable(self.discoverable)
 
         # Let the SMP manager know about the address
         # TODO: allow using a public address
@@ -1497,7 +1507,6 @@ class Device(CompositeEventEmitter):
     def on_pairing_failure(self, connection, reason):
         connection.emit('pairing_failure', reason)
 
-    @host_event_handler
     @with_connection_from_handle
     def on_gatt_pdu(self, connection, pdu):
         # Parse the L2CAP payload into an ATT PDU object
@@ -1516,7 +1525,6 @@ class Device(CompositeEventEmitter):
                 return
             connection.gatt_server.on_gatt_pdu(connection, att_pdu)
 
-    @host_event_handler
     @with_connection_from_handle
     def on_smp_pdu(self, connection, pdu):
         self.smp_manager.on_smp_pdu(connection, pdu)

bumble/host.py

@@ -56,13 +56,7 @@ class Connection:
 
     def on_acl_pdu(self, pdu):
         l2cap_pdu = L2CAP_PDU.from_bytes(pdu)
-
-        if l2cap_pdu.cid == ATT_CID:
-            self.host.on_gatt_pdu(self, l2cap_pdu.payload)
-        elif l2cap_pdu.cid == SMP_CID:
-            self.host.on_smp_pdu(self, l2cap_pdu.payload)
-        else:
-            self.host.on_l2cap_pdu(self, l2cap_pdu.cid, l2cap_pdu.payload)
+        self.host.on_l2cap_pdu(self, l2cap_pdu.cid, l2cap_pdu.payload)
 
 
 # -----------------------------------------------------------------------------
@@ -299,12 +293,6 @@ class Host(EventEmitter):
         if connection := self.connections.get(packet.connection_handle):
             connection.on_hci_acl_data_packet(packet)
 
-    def on_gatt_pdu(self, connection, pdu):
-        self.emit('gatt_pdu', connection.handle, pdu)
-
-    def on_smp_pdu(self, connection, pdu):
-        self.emit('smp_pdu', connection.handle, pdu)
-
     def on_l2cap_pdu(self, connection, cid, pdu):
         self.emit('l2cap_pdu', connection.handle, cid, pdu)
 

bumble/l2cap.py

@@ -20,11 +20,11 @@ import logging
 import struct
 
 from colors import color
+from pyee import EventEmitter
 
 from .core import BT_CENTRAL_ROLE, InvalidStateError, ProtocolError
 from .hci import (HCI_LE_Connection_Update_Command, HCI_Object, key_with_value,
                   name_or_number)
-from .utils import EventEmitter
 
 # -----------------------------------------------------------------------------
 # Logging
@@ -414,6 +414,18 @@ class L2CAP_Information_Request(L2CAP_Control_Frame):
     EXTENDED_FEATURES_SUPPORTED = 0x0002
     FIXED_CHANNELS_SUPPORTED    = 0x0003
 
+    EXTENDED_FEATURE_FLOW_MODE_CONTROL                 = 0x0001
+    EXTENDED_FEATURE_RETRANSMISSION_MODE               = 0x0002
+    EXTENDED_FEATURE_BIDIRECTIONAL_QOS                 = 0x0004
+    EXTENDED_FEATURE_ENHANCED_RETRANSMISSION_MODE      = 0x0008
+    EXTENDED_FEATURE_STREAMING_MODE                    = 0x0010
+    EXTENDED_FEATURE_FCS_OPTION                        = 0x0020
+    EXTENDED_FEATURE_EXTENDED_FLOW_SPEC                = 0x0040
+    EXTENDED_FEATURE_FIXED_CHANNELS                    = 0x0080
+    EXTENDED_FEATURE_EXTENDED_WINDOW_SIZE              = 0x0100
+    EXTENDED_FEATURE_UNICAST_CONNECTIONLESS_DATA       = 0x0200
+    EXTENDED_FEATURE_ENHANCED_CREDIT_BASE_FLOW_CONTROL = 0x0400
+
     INFO_TYPE_NAMES = {
         CONNECTIONLESS_MTU:          'CONNECTIONLESS_MTU',
         EXTENDED_FEATURES_SUPPORTED: 'EXTENDED_FEATURES_SUPPORTED',
@@ -817,11 +829,16 @@ class Channel(EventEmitter):
 
 # -----------------------------------------------------------------------------
 class ChannelManager:
-    def __init__(self):
-        self.host        = None
-        self.channels    = {}  # Channels, mapped by connection and cid
-        self.identifiers = {}  # Incrementing identifier values by connection
-        self.servers     = {}  # Servers accepting connections, by PSM
+    def __init__(self, extended_features=None, connectionless_mtu=1024):
+        self.host               = None
+        self.channels           = {}  # Channels, mapped by connection and cid
+        # Fixed channel handlers, mapped by cid
+        self.fixed_channels     = {
+            L2CAP_SIGNALING_CID: None, L2CAP_LE_SIGNALING_CID: None}
+        self.identifiers        = {}  # Incrementing identifier values by connection
+        self.servers            = {}  # Servers accepting connections, by PSM
+        self.extended_features  = [] if extended_features is None else extended_features
+        self.connectionless_mtu = connectionless_mtu
 
     def find_channel(self, connection_handle, cid):
         if connection_channels := self.channels.get(connection_handle):
@@ -840,6 +857,13 @@ class ChannelManager:
         identifier = (self.identifiers.setdefault(connection.handle, 0) + 1) % 256
         self.identifiers[connection.handle] = identifier
         return identifier
+    
+    def register_fixed_channel(self, cid, handler):
+        self.fixed_channels[cid] = handler
+    
+    def deregister_fixed_channel(self, cid):
+        if cid in self.fixed_channels:
+            del self.fixed_channels[cid]
 
     def register_server(self, psm, server):
         self.servers[psm] = server
@@ -855,6 +879,8 @@ class ChannelManager:
             control_frame = L2CAP_Control_Frame.from_bytes(pdu)
 
             self.on_control_frame(connection, cid, control_frame)
+        elif cid in self.fixed_channels:
+            self.fixed_channels[cid](connection.handle, pdu)
         else:
             if (channel := self.find_channel(connection.handle, cid)) is None:
                 logger.warn(color(f'channel not found for 0x{connection.handle:04X}:{cid}', 'red'))
@@ -999,13 +1025,13 @@ class ChannelManager:
     def on_l2cap_information_request(self, connection, cid, request):
         if request.info_type == L2CAP_Information_Request.CONNECTIONLESS_MTU:
             result = L2CAP_Information_Response.SUCCESS
-            data = struct.pack('<H', 1024)  # TODO: don't use a fixed value
+            data = self.connectionless_mtu.to_bytes(2, 'little')
         elif request.info_type == L2CAP_Information_Request.EXTENDED_FEATURES_SUPPORTED:
             result = L2CAP_Information_Response.SUCCESS
-            data = bytes.fromhex('00000000')  # TODO: don't use a fixed value
+            data = sum(self.extended_features).to_bytes(4, 'little')
         elif request.info_type == L2CAP_Information_Request.FIXED_CHANNELS_SUPPORTED:
             result = L2CAP_Information_Response.SUCCESS
-            data = bytes.fromhex('FFFFFFFFFFFFFFFF')  # TODO: don't use a fixed value
+            data = sum(1 << cid for cid in self.fixed_channels).to_bytes(8, 'little')
         else:
             result = L2CAP_Information_Request.NO_SUPPORTED
 

bumble/rfcomm.py

@@ -17,9 +17,10 @@
 # -----------------------------------------------------------------------------
 import logging
 import asyncio
-from colors import color
 
-from .utils import EventEmitter
+from colors import color
+from pyee import EventEmitter
+
 from .core import InvalidStateError, ProtocolError, ConnectionError
 
 # -----------------------------------------------------------------------------

docs/mkdocs/src/apps_and_tools/console.md

@@ -7,10 +7,12 @@ The Console app is an interactive text user interface that offers a number of fu
 
   * scanning
   * advertising
-  * connecting to devices
+  * connecting to and disconnecting from devices
   * changing connection parameters
+  * enabling encryption
   * discovering GATT services and characteristics
-  * read & write GATT characteristics
+  * reading and writing GATT characteristics
+  * subscribing to and unsubscribing from GATT characteristics
 
 The console user interface has 3 main panes:
 

setup.cfg

@@ -57,12 +57,13 @@ console_scripts =
     bumble-link-relay = bumble.apps.link_relay.link_relay:main
 
 [options.extras_require]
+build = 
+    build >= 0.7
 test =
     pytest >= 6.2
     pytest-asyncio >= 0.17
 development =
     invoke >= 1.4
-    build >= 0.7
     nox >= 2022
 documentation =
     mkdocs >= 1.2.3

tasks.py

@@ -23,35 +23,52 @@ ROOT_DIR = os.path.dirname(os.path.realpath(__file__))
 
 ns = Collection()
 
+# Building
 build_tasks = Collection()
-ns.add_collection(build_tasks, name='build')
-
+ns.add_collection(build_tasks, name="build")
 
 @task
-def build(ctx):
-    ctx.run('python -m build')
+def build(ctx, install=False):
+    if install:
+        ctx.run('python -m pip install .[build]')
 
-build_tasks.add_task(build, default=True, name='build')
+    ctx.run("python -m build")
 
+build_tasks.add_task(build, default=True)
+
+@task
+def release_build(ctx):
+    build(ctx, install=True)
+
+build_tasks.add_task(release_build, name="release")
+
+@task
+def mkdocs(ctx):
+    ctx.run("mkdocs build -f docs/mkdocs/mkdocs.yml")
+
+build_tasks.add_task(mkdocs, name="mkdocs")
+
+# Testing
 test_tasks = Collection()
-ns.add_collection(test_tasks, name='test')
+ns.add_collection(test_tasks, name="test")
 
 @task
-def test(ctx, filter=None, junit=False):
+def test(ctx, filter=None, junit=False, install=False):
+    # Install the package before running the tests
+    if install:
+        ctx.run("python -m pip install .[test]")
+
     args = ""
     if junit:
         args += "--junit-xml test-results.xml"
     if filter is not None:
         args += " -k '{}'".format(filter)
-    ctx.run('python -m pytest {} {}'
-            .format(os.path.join(ROOT_DIR, "tests"), args))
-
-test_tasks.add_task(test, name='test', default=True)
+    ctx.run("python -m pytest {} {}".format(os.path.join(ROOT_DIR, "tests"), args))
 
+test_tasks.add_task(test, default=True)
 
 @task
-def mkdocs(ctx):
-    ctx.run('mkdocs build -f docs/mkdocs/mkdocs.yml')
+def release_test(ctx):
+    test(ctx, install=True)
 
-
-ns.add_task(mkdocs)
+test_tasks.add_task(release_test, name="release")