@corbet
> But it misses an important point
My use case used to be quite the opposite when not in my mobile network (travelling): some sketchy WiFi avail. which I was desperate to connect my laptop to but only could do through my phone. Fancy auth my phone could do (but not the laptop) easily worked-around by using phone's MAC, but in some situations it used to be more than that. So always wished to be able to tether to the WiFi.
Sorry for not answering your question
@corbet I don't think you can. Remember when teathering you're simply using the phone's global default route, which is preprogrammed to prefer WiFi over mobile. The phone could run a new network ns with a different default route and teather you to it, but that feature doesn't exist in AOSP.
@corbet Another usecase would be to give access to the second wifi without exposing the credentials. It's easier to renew the settings on the tethering device without affecting all those clients connected to the wifi.
But yes - sounds silly.
@corbet fwiw, I've found this feature useful when either my laptop's wifi antenna was insufficient or there was some strange incompatability with a wifi network