Randomize thread network names (#108302)

* Randomize thread network names

* Use PAN ID as network name suffix

* Apply suggestions from code review

Co-authored-by: Stefan Agner <stefan@agner.ch>

* Update tests

* Format code

* Change format of network name again

---------

Co-authored-by: Stefan Agner <stefan@agner.ch>

homeassistant/components/otbr/config_flow.py

@@ -28,7 +28,11 @@ from homeassistant.exceptions import HomeAssistantError
 from homeassistant.helpers.aiohttp_client import async_get_clientsession
 
 from .const import DEFAULT_CHANNEL, DOMAIN
-from .util import get_allowed_channel
+from .util import (
+    compose_default_network_name,
+    generate_random_pan_id,
+    get_allowed_channel,
+)
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -85,10 +89,12 @@ class OTBRConfigFlow(ConfigFlow, domain=DOMAIN):
                 _LOGGER.debug(
                     "not importing TLV with channel %s", thread_dataset_channel
                 )
+                pan_id = generate_random_pan_id()
                 await api.create_active_dataset(
                     python_otbr_api.ActiveDataSet(
                         channel=allowed_channel if allowed_channel else DEFAULT_CHANNEL,
-                        network_name="home-assistant",
+                        network_name=compose_default_network_name(pan_id),
+                        pan_id=pan_id,
                     )
                 )
             await api.set_enabled(True)

homeassistant/components/otbr/util.py

@@ -5,6 +5,7 @@ from collections.abc import Callable, Coroutine
 import dataclasses
 from functools import wraps
 import logging
+import random
 from typing import Any, Concatenate, ParamSpec, TypeVar, cast
 
 import python_otbr_api
@@ -48,6 +49,17 @@ INSECURE_PASSPHRASES = (
 )
 
 
+def compose_default_network_name(pan_id: int) -> str:
+    """Generate a default network name."""
+    return f"ha-thread-{pan_id:04x}"
+
+
+def generate_random_pan_id() -> int:
+    """Generate a random PAN ID."""
+    # PAN ID is 2 bytes, 0xffff is reserved for broadcast
+    return random.randint(0, 0xFFFE)
+
+
 def _handle_otbr_error(
     func: Callable[Concatenate[OTBRData, _P], Coroutine[Any, Any, _R]],
 ) -> Callable[Concatenate[OTBRData, _P], Coroutine[Any, Any, _R]]:

homeassistant/components/otbr/websocket_api.py

@@ -16,7 +16,13 @@ from homeassistant.core import HomeAssistant, callback
 from homeassistant.exceptions import HomeAssistantError
 
 from .const import DEFAULT_CHANNEL, DOMAIN
-from .util import OTBRData, get_allowed_channel, update_issues
+from .util import (
+    OTBRData,
+    compose_default_network_name,
+    generate_random_pan_id,
+    get_allowed_channel,
+    update_issues,
+)
 
 
 @callback
@@ -99,10 +105,13 @@ async def websocket_create_network(
         connection.send_error(msg["id"], "factory_reset_failed", str(exc))
         return
 
+    pan_id = generate_random_pan_id()
     try:
         await data.create_active_dataset(
             python_otbr_api.ActiveDataSet(
-                channel=channel, network_name="home-assistant"
+                channel=channel,
+                network_name=compose_default_network_name(pan_id),
+                pan_id=pan_id,
             )
         )
     except HomeAssistantError as exc:

tests/components/otbr/test_config_flow.py

@@ -121,9 +121,11 @@ async def test_user_flow_router_not_setup(
     # Check we create a dataset and enable the router
     assert aioclient_mock.mock_calls[-2][0] == "PUT"
     assert aioclient_mock.mock_calls[-2][1].path == "/node/dataset/active"
+    pan_id = aioclient_mock.mock_calls[-2][2]["PanId"]
     assert aioclient_mock.mock_calls[-2][2] == {
         "Channel": 15,
-        "NetworkName": "home-assistant",
+        "NetworkName": f"ha-thread-{pan_id:04x}",
+        "PanId": pan_id,
     }
 
     assert aioclient_mock.mock_calls[-1][0] == "PUT"
@@ -425,9 +427,11 @@ async def test_hassio_discovery_flow_router_not_setup(
     # Check we create a dataset and enable the router
     assert aioclient_mock.mock_calls[-2][0] == "PUT"
     assert aioclient_mock.mock_calls[-2][1].path == "/node/dataset/active"
+    pan_id = aioclient_mock.mock_calls[-2][2]["PanId"]
     assert aioclient_mock.mock_calls[-2][2] == {
         "Channel": 15,
-        "NetworkName": "home-assistant",
+        "NetworkName": f"ha-thread-{pan_id:04x}",
+        "PanId": pan_id,
     }
 
     assert aioclient_mock.mock_calls[-1][0] == "PUT"
@@ -532,9 +536,11 @@ async def test_hassio_discovery_flow_router_not_setup_has_preferred_2(
     # Check we create a dataset and enable the router
     assert aioclient_mock.mock_calls[-2][0] == "PUT"
     assert aioclient_mock.mock_calls[-2][1].path == "/node/dataset/active"
+    pan_id = aioclient_mock.mock_calls[-2][2]["PanId"]
     assert aioclient_mock.mock_calls[-2][2] == {
         "Channel": 15,
-        "NetworkName": "home-assistant",
+        "NetworkName": f"ha-thread-{pan_id:04x}",
+        "PanId": pan_id,
     }
 
     assert aioclient_mock.mock_calls[-1][0] == "PUT"

tests/components/otbr/test_websocket_api.py

@@ -105,7 +105,10 @@ async def test_create_network(
         "python_otbr_api.OTBR.get_active_dataset_tlvs", return_value=DATASET_CH16
     ) as get_active_dataset_tlvs_mock, patch(
         "homeassistant.components.thread.dataset_store.DatasetStore.async_add"
-    ) as mock_add:
+    ) as mock_add, patch(
+        "homeassistant.components.otbr.util.random.randint",
+        return_value=0x1234,
+    ):
         await websocket_client.send_json_auto_id({"type": "otbr/create_network"})
 
         msg = await websocket_client.receive_json()
@@ -113,7 +116,9 @@ async def test_create_network(
         assert msg["result"] is None
 
     create_dataset_mock.assert_called_once_with(
-        python_otbr_api.models.ActiveDataSet(channel=15, network_name="home-assistant")
+        python_otbr_api.models.ActiveDataSet(
+            channel=15, network_name="ha-thread-1234", pan_id=0x1234
+        )
     )
     factory_reset_mock.assert_called_once_with()
     assert len(set_enabled_mock.mock_calls) == 2