core: HomeKit Controller - Does not follow TCP port change

The problem

I use a Starling Home Hub as a HomeKit bridge for some Nest devices that aren’t (yet?) supported, such as door, alarm, and temperature sensors. When the Starling reboots (esp. after a firmware update), its TCP port being used for HomeKit integration may change. According to the developer, this is in line with the HomeKit specification, and connecting devices are supposed to use an mDNS query to look up the port for connecting.

It appears that for the HomeKit Controller component, however, the port is fixed in the core.config_entries file. In my log files you can see HA repeatedly trying to connect to the Starling hub on the old TCP port.

According to the Starling developer:

The right way to discover the port is to do an mDNS query for _hap._tcp to the hub. The port number of the HomeKit service will be returned in the SRV record. This is what HomeKit itself does.

I’m unsure if this is a HomeKit Controller component issue, or an aiohomekit issue that’s causing it to not re-query the port.

And indeed, when I query the device I get back its new TCP port. I can manually update core.config_entries for the HomeKit Controller device and change the AccessoryPort property to the new port, restart HA, and it will start working again.

Example of how to query for the correct TCP port (converted from hex to decimal):

dig @192.168.X.X -p 5353 -t ptr _hap._tcp.local | grep SRV | awk '{print $7}' | echo "obase=10; ibase=16; $(cut -c9-12)" | bc

What is version of Home Assistant Core has the issue?

core-2021.6.4

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant Core

Integration causing the issue

HomeKit Controller

Link to integration documentation on our website

https://www.home-assistant.io/integrations/homekit_controller/

Example YAML snippet

No response

Anything in the logs that might be useful for us?

2021-06-14 08:23:19 DEBUG (MainThread) [homeassistant.components.homekit_controller.connection] Starting HomeKit controller update: [redacted MAC]
2021-06-14 08:23:29 DEBUG (MainThread) [homeassistant.components.homekit_controller.connection] Called async_set_available_state with False for [redacted MAC]
2021-06-14 08:23:31 DEBUG (MainThread) [aiohomekit.controller.ip.connection] Attempting connection to 192.168.X.X:40313
2021-06-14 08:23:31 DEBUG (MainThread) [aiohomekit.controller.ip.connection] Connecting to accessory failed. Retrying in 60 seconds
2021-06-14 08:24:19 DEBUG (MainThread) [homeassistant.components.homekit_controller.connection] Starting HomeKit controller update: [redacted MAC]
2021-06-14 08:24:29 DEBUG (MainThread) [homeassistant.components.homekit_controller.connection] Called async_set_available_state with False for [redacted MAC]
2021-06-14 08:24:31 DEBUG (MainThread) [aiohomekit.controller.ip.connection] Attempting connection to 192.168.X.X:40313
2021-06-14 08:24:31 DEBUG (MainThread) [aiohomekit.controller.ip.connection] Connecting to accessory failed. Retrying in 60 seconds

Additional information

No response