Complete CSIP and CAP

Also add random address generation functions.

bumble/crypto.py

@@ -100,6 +100,16 @@ class EccKey:
 # -----------------------------------------------------------------------------
 
 
+# -----------------------------------------------------------------------------
+def generate_prand() -> bytes:
+    '''Generates random 3 bytes, with the 2 most significant bits of 0b01.
+
+    See Bluetooth spec, Vol 6, Part E - Table 1.2.
+    '''
+    prand_bytes = secrets.token_bytes(6)
+    return prand_bytes[:2] + bytes([(prand_bytes[2] & 0b01111111) | 0b01000000])
+
+
 # -----------------------------------------------------------------------------
 def xor(x: bytes, y: bytes) -> bytes:
     assert len(x) == len(y)

bumble/gatt.py

@@ -368,9 +368,12 @@ class TemplateService(Service):
     UUID: UUID
 
     def __init__(
-        self, characteristics: List[Characteristic], primary: bool = True
+        self,
+        characteristics: List[Characteristic],
+        primary: bool = True,
+        included_services: List[Service] = [],
     ) -> None:
-        super().__init__(self.UUID, characteristics, primary)
+        super().__init__(self.UUID, characteristics, primary, included_services)
 
 
 # -----------------------------------------------------------------------------

bumble/profiles/cap.py

@@ -0,0 +1,52 @@
+# Copyright 2021-2023 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
+# -----------------------------------------------------------------------------
+from __future__ import annotations
+
+from bumble import gatt
+from bumble import gatt_client
+from bumble.profiles import csip
+
+
+# -----------------------------------------------------------------------------
+# Server
+# -----------------------------------------------------------------------------
+class CommonAudioServiceService(gatt.TemplateService):
+    UUID = gatt.GATT_COMMON_AUDIO_SERVICE
+
+    def __init__(
+        self,
+        coordinated_set_identification_service: csip.CoordinatedSetIdentificationService,
+    ) -> None:
+        self.coordinated_set_identification_service = (
+            coordinated_set_identification_service
+        )
+        super().__init__(
+            characteristics=[],
+            included_services=[coordinated_set_identification_service],
+        )
+
+
+# -----------------------------------------------------------------------------
+# Client
+# -----------------------------------------------------------------------------
+class CommonAudioServiceServiceProxy(gatt_client.ProfileServiceProxy):
+    SERVICE_CLASS = CommonAudioServiceService
+
+    def __init__(self, service_proxy: gatt_client.ServiceProxy) -> None:
+        self.service_proxy = service_proxy

bumble/profiles/csip.py

@@ -21,6 +21,9 @@ import enum
 import struct
 from typing import Optional
 
+from bumble import core
+from bumble import crypto
+from bumble import device
 from bumble import gatt
 from bumble import gatt_client
 
@@ -43,9 +46,43 @@ class MemberLock(enum.IntEnum):
 
 
 # -----------------------------------------------------------------------------
-# Utils
+# Crypto Toolbox
 # -----------------------------------------------------------------------------
-# TODO: Implement RSI Generator
+def s1(m: bytes) -> bytes:
+    '''
+    Coordinated Set Identification Service - 4.3 s1 SALT generation function.
+    '''
+    return crypto.aes_cmac(m[::-1], bytes(16))[::-1]
+
+
+def k1(n: bytes, salt: bytes, p: bytes) -> bytes:
+    '''
+    Coordinated Set Identification Service - 4.4 k1 derivation function.
+    '''
+    t = crypto.aes_cmac(n[::-1], salt[::-1])
+    return crypto.aes_cmac(p[::-1], t)[::-1]
+
+
+def sef(k: bytes, r: bytes) -> bytes:
+    '''
+    Coordinated Set Identification Service - 4.5 SIRK encryption function sef.
+    '''
+    return crypto.xor(k1(k, s1(b'SIRKenc'[::-1]), b'csis'[::-1]), r)
+
+
+def sih(k: bytes, r: bytes) -> bytes:
+    '''
+    Coordinated Set Identification Service - 4.7 Resolvable Set Identifier hash function sih.
+    '''
+    return crypto.e(k, r + bytes(13))[:3]
+
+
+def generate_rsi(sirk: bytes) -> bytes:
+    '''
+    Coordinated Set Identification Service - 4.8 Resolvable Set Identifier generation operation.
+    '''
+    prand = crypto.generate_prand()
+    return sih(sirk, prand) + prand
 
 
 # -----------------------------------------------------------------------------
@@ -54,6 +91,7 @@ class MemberLock(enum.IntEnum):
 class CoordinatedSetIdentificationService(gatt.TemplateService):
     UUID = gatt.GATT_COORDINATED_SET_IDENTIFICATION_SERVICE
 
+    set_identity_resolving_key: bytes
     set_identity_resolving_key_characteristic: gatt.Characteristic
     coordinated_set_size_characteristic: Optional[gatt.Characteristic] = None
     set_member_lock_characteristic: Optional[gatt.Characteristic] = None
@@ -62,19 +100,21 @@ class CoordinatedSetIdentificationService(gatt.TemplateService):
     def __init__(
         self,
         set_identity_resolving_key: bytes,
+        set_identity_resolving_key_type: SirkType,
         coordinated_set_size: Optional[int] = None,
         set_member_lock: Optional[MemberLock] = None,
         set_member_rank: Optional[int] = None,
     ) -> None:
         characteristics = []
 
+        self.set_identity_resolving_key = set_identity_resolving_key
+        self.set_identity_resolving_key_type = set_identity_resolving_key_type
         self.set_identity_resolving_key_characteristic = gatt.Characteristic(
             uuid=gatt.GATT_SET_IDENTITY_RESOLVING_KEY_CHARACTERISTIC,
             properties=gatt.Characteristic.Properties.READ
             | gatt.Characteristic.Properties.NOTIFY,
             permissions=gatt.Characteristic.Permissions.READABLE,
-            # TODO: Implement encrypted SIRK reader.
+            value=gatt.CharacteristicValue(read=self.on_sirk_read),
-            value=struct.pack('B', SirkType.PLAINTEXT) + set_identity_resolving_key,
         )
         characteristics.append(self.set_identity_resolving_key_characteristic)
 
@@ -112,6 +152,24 @@ class CoordinatedSetIdentificationService(gatt.TemplateService):
 
         super().__init__(characteristics)
 
+    def on_sirk_read(self, _connection: device.Connection) -> bytes:
+        if self.set_identity_resolving_key_type == SirkType.PLAINTEXT:
+            return bytes([SirkType.PLAINTEXT]) + self.set_identity_resolving_key
+        else:
+            raise NotImplementedError('TODO: Pending async Characteristic read.')
+
+    def get_advertising_data(self) -> bytes:
+        return bytes(
+            core.AdvertisingData(
+                [
+                    (
+                        core.AdvertisingData.RESOLVABLE_SET_IDENTIFIER,
+                        generate_rsi(self.set_identity_resolving_key),
+                    ),
+                ]
+            )
+        )
+
 
 # -----------------------------------------------------------------------------
 # Client

examples/run_csis_servers.py

@@ -0,0 +1,116 @@
+# Copyright 2021-2023 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 logging
+import sys
+import os
+import secrets
+
+from bumble.core import AdvertisingData
+from bumble.device import Device
+from bumble.hci import (
+    Address,
+    OwnAddressType,
+    HCI_LE_Set_Extended_Advertising_Parameters_Command,
+)
+from bumble.profiles.cap import CommonAudioServiceService
+from bumble.profiles.csip import CoordinatedSetIdentificationService, SirkType
+
+from bumble.transport import open_transport_or_link
+
+
+# -----------------------------------------------------------------------------
+async def main() -> None:
+    if len(sys.argv) < 3:
+        print(
+            'Usage: run_cig_setup.py <config-file>'
+            '<transport-spec-for-device-1> <transport-spec-for-device-2>'
+        )
+        print(
+            'example: run_cig_setup.py device1.json'
+            'tcp-client:127.0.0.1:6402 tcp-client:127.0.0.1:6402'
+        )
+        return
+
+    print('<<< connecting to HCI...')
+    hci_transports = await asyncio.gather(
+        open_transport_or_link(sys.argv[2]), open_transport_or_link(sys.argv[3])
+    )
+    print('<<< connected')
+
+    devices = [
+        Device.from_config_file_with_hci(
+            sys.argv[1], hci_transport.source, hci_transport.sink
+        )
+        for hci_transport in hci_transports
+    ]
+
+    sirk = secrets.token_bytes(16)
+
+    for i, device in enumerate(devices):
+        device.random_address = Address(secrets.token_bytes(6))
+        await device.power_on()
+        csis = CoordinatedSetIdentificationService(
+            set_identity_resolving_key=sirk,
+            set_identity_resolving_key_type=SirkType.PLAINTEXT,
+            coordinated_set_size=2,
+        )
+        device.add_service(CommonAudioServiceService(csis))
+        advertising_data = (
+            bytes(
+                AdvertisingData(
+                    [
+                        (
+                            AdvertisingData.COMPLETE_LOCAL_NAME,
+                            bytes(f'Bumble LE Audio-{i}', 'utf-8'),
+                        ),
+                        (
+                            AdvertisingData.FLAGS,
+                            bytes(
+                                [
+                                    AdvertisingData.LE_GENERAL_DISCOVERABLE_MODE_FLAG
+                                    | AdvertisingData.BR_EDR_HOST_FLAG
+                                    | AdvertisingData.BR_EDR_CONTROLLER_FLAG
+                                ]
+                            ),
+                        ),
+                        (
+                            AdvertisingData.INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS,
+                            bytes(CoordinatedSetIdentificationService.UUID),
+                        ),
+                    ]
+                )
+            )
+            + csis.get_advertising_data()
+        )
+        await device.start_extended_advertising(
+            advertising_properties=(
+                HCI_LE_Set_Extended_Advertising_Parameters_Command.AdvertisingProperties.CONNECTABLE_ADVERTISING
+            ),
+            own_address_type=OwnAddressType.RANDOM,
+            advertising_data=advertising_data,
+        )
+
+    await asyncio.gather(
+        *[hci_transport.source.terminated for hci_transport in hci_transports]
+    )
+
+
+# -----------------------------------------------------------------------------
+logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'DEBUG').upper())
+asyncio.run(main())

examples/run_unicast_server.py

@@ -20,6 +20,7 @@ import logging
 import sys
 import os
 import struct
+import secrets
 from bumble.core import AdvertisingData
 from bumble.device import Device, CisLink
 from bumble.hci import (
@@ -39,6 +40,8 @@ from bumble.profiles.bap import (
     PublishedAudioCapabilitiesService,
     AudioStreamControlService,
 )
+from bumble.profiles.cap import CommonAudioServiceService
+from bumble.profiles.csip import CoordinatedSetIdentificationService, SirkType
 
 from bumble.transport import open_transport_or_link
 
@@ -60,6 +63,11 @@ async def main() -> None:
 
         await device.power_on()
 
+        csis = CoordinatedSetIdentificationService(
+            set_identity_resolving_key=secrets.token_bytes(16),
+            set_identity_resolving_key_type=SirkType.PLAINTEXT,
+        )
+        device.add_service(CommonAudioServiceService(csis))
         device.add_service(
             PublishedAudioCapabilitiesService(
                 supported_source_context=ContextType.PROHIBITED,
@@ -108,29 +116,32 @@ async def main() -> None:
 
         device.add_service(AudioStreamControlService(device, sink_ase_id=[1, 2]))
 
-        advertising_data = bytes(
+        advertising_data = (
-            AdvertisingData(
+            bytes(
-                [
+                AdvertisingData(
-                    (
+                    [
-                        AdvertisingData.COMPLETE_LOCAL_NAME,
+                        (
-                        bytes('Bumble LE Audio', 'utf-8'),
+                            AdvertisingData.COMPLETE_LOCAL_NAME,
-                    ),
+                            bytes('Bumble LE Audio', 'utf-8'),
-                    (
-                        AdvertisingData.FLAGS,
-                        bytes(
-                            [
-                                AdvertisingData.LE_GENERAL_DISCOVERABLE_MODE_FLAG
-                                | AdvertisingData.BR_EDR_HOST_FLAG
-                                | AdvertisingData.BR_EDR_CONTROLLER_FLAG
-                            ]
                         ),
-                    ),
+                        (
-                    (
+                            AdvertisingData.FLAGS,
-                        AdvertisingData.INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS,
+                            bytes(
-                        bytes(PublishedAudioCapabilitiesService.UUID),
+                                [
-                    ),
+                                    AdvertisingData.LE_GENERAL_DISCOVERABLE_MODE_FLAG
-                ]
+                                    | AdvertisingData.BR_EDR_HOST_FLAG
+                                    | AdvertisingData.BR_EDR_CONTROLLER_FLAG
+                                ]
+                            ),
+                        ),
+                        (
+                            AdvertisingData.INCOMPLETE_LIST_OF_16_BIT_SERVICE_CLASS_UUIDS,
+                            bytes(PublishedAudioCapabilitiesService.UUID),
+                        ),
+                    ]
+                )
             )
+            + csis.get_advertising_data()
         )
         subprocess = await asyncio.create_subprocess_shell(
             f'dlc3 | ffplay pipe:0',

tests/cap_test.py

@@ -0,0 +1,71 @@
+# Copyright 2021-2023 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 os
+import pytest
+import logging
+
+from bumble import device
+from bumble import gatt
+from bumble.profiles import cap
+from bumble.profiles import csip
+from .test_utils import TwoDevices
+
+# -----------------------------------------------------------------------------
+# Logging
+# -----------------------------------------------------------------------------
+logger = logging.getLogger(__name__)
+
+
+# -----------------------------------------------------------------------------
+@pytest.mark.asyncio
+async def test_cas():
+    SIRK = bytes.fromhex('2f62c8ae41867d1bb619e788a2605faa')
+
+    devices = TwoDevices()
+    devices[0].add_service(
+        cap.CommonAudioServiceService(
+            csip.CoordinatedSetIdentificationService(
+                set_identity_resolving_key=SIRK,
+                set_identity_resolving_key_type=csip.SirkType.PLAINTEXT,
+            )
+        )
+    )
+
+    await devices.setup_connection()
+    peer = device.Peer(devices.connections[1])
+    cas_client = await peer.discover_service_and_create_proxy(
+        cap.CommonAudioServiceServiceProxy
+    )
+
+    included_services = await peer.discover_included_services(cas_client.service_proxy)
+    assert any(
+        service.uuid == gatt.GATT_COORDINATED_SET_IDENTIFICATION_SERVICE
+        for service in included_services
+    )
+
+
+# -----------------------------------------------------------------------------
+async def run():
+    await test_cas()
+
+
+# -----------------------------------------------------------------------------
+if __name__ == '__main__':
+    logging.basicConfig(level=os.environ.get('BUMBLE_LOGLEVEL', 'INFO').upper())
+    asyncio.run(run())

tests/csip_test.py

@@ -31,6 +31,41 @@ from .test_utils import TwoDevices
 logger = logging.getLogger(__name__)
 
 
+# -----------------------------------------------------------------------------
+def test_s1():
+    assert (
+        csip.s1(b'SIRKenc'[::-1])
+        == bytes.fromhex('6901983f 18149e82 3c7d133a 7d774572')[::-1]
+    )
+
+
+# -----------------------------------------------------------------------------
+def test_k1():
+    K = bytes.fromhex('676e1b9b d448696f 061ec622 3ce5ced9')[::-1]
+    SALT = csip.s1(b'SIRKenc'[::-1])
+    P = b'csis'[::-1]
+    assert (
+        csip.k1(K, SALT, P)
+        == bytes.fromhex('5277453c c094d982 b0e8ee53 2f2d1f8b')[::-1]
+    )
+
+
+# -----------------------------------------------------------------------------
+def test_sih():
+    SIRK = bytes.fromhex('457d7d09 21a1fd22 cecd8c86 dd72cccd')[::-1]
+    PRAND = bytes.fromhex('69f563')[::-1]
+    assert csip.sih(SIRK, PRAND) == bytes.fromhex('1948da')[::-1]
+
+
+# -----------------------------------------------------------------------------
+def test_sef():
+    SIRK = bytes.fromhex('457d7d09 21a1fd22 cecd8c86 dd72cccd')[::-1]
+    K = bytes.fromhex('676e1b9b d448696f 061ec622 3ce5ced9')[::-1]
+    assert (
+        csip.sef(K, SIRK) == bytes.fromhex('170a3835 e13524a0 7e2562d5 f25fd346')[::-1]
+    )
+
+
 # -----------------------------------------------------------------------------
 @pytest.mark.asyncio
 async def test_csis():
@@ -40,6 +75,7 @@ async def test_csis():
     devices[0].add_service(
         csip.CoordinatedSetIdentificationService(
             set_identity_resolving_key=SIRK,
+            set_identity_resolving_key_type=csip.SirkType.PLAINTEXT,
             coordinated_set_size=2,
             set_member_lock=csip.MemberLock.UNLOCKED,
             set_member_rank=0,
@@ -65,6 +101,7 @@ async def test_csis():
 
 # -----------------------------------------------------------------------------
 async def run():
+    test_sih()
     await test_csis()