Possible to select which network interface to use?

Question

I have an app which is used to connect to a service running on the user's home PC.

There are two 'simple' scenarios...

1. The user has wi-fi enabled on their device and simply connects using their home WLAN.
2. The user is away from a wi-fi connection and they are able to connect with mobile internet

I'm now faced with a more complex scenario which is when the user is at their place of work and their device detects/connects to their office WLAN and there is no route to the outside world.

The problem is that even if they have both wi-fi AND mobile internet enabled on their device, the wi-fi interface will normally be used in preference to the mobile internet interface when any app attempts to connect to the internet.

So the question is, can I somehow bind to the mobile interface and make an outgoing connection even when the wi-fi interface is taking priority? If so, any pointers to information on how to achieve this would be useful. Thanks.

Answer 1

This is where I would start digging. ConnectivityManager.requestRouteToHost

The primary responsibilities of this class are to:

Monitor network connections (Wi-Fi,GPRS, UMTS, etc.)

Send broadcast intents when network connectivity changes

Attempt to "fail over" to another network when connectivity to a network is lost

Provide an API that allows applications to query the coarse-grained or fine-grained state of the available networks

I'd also try grep'ing over the AOSP code to see where and how it is used.