Release mobile request when default upstream is not mobile
Some OEM may have special mobile data icon show up when non-default
(e.g. DUN) mobile connection connected even wifi is also connected.
So always connected DUN may let user hard to distinguish tethering
upstream in those OEM's devices. Also release unused mobile connection
may safe power.
This CL removes unnecessary code from selectPreferredUpstreamType.
In particular:
- When a DUN or HIPRI upstream is selected, calling
registerMobileNetworkRequest is unnecessary. A mobile
NetworkRequest is always registered unless a non-mobile upstream
is selected.
- When a non-mobile upstream is found, releasing the mobile
NetworkRequest is unnecessary in selectPreferredUpstreamType
because it will be done by chooseUpstreamType immediately after
selectPreferredUpstreamType returns.
- When no upstream is found and cellular upstream is not permitted,
it is not necessary to release the mobile NetworkRequest. When
cellular is not permitted, no such NetworkRequest will be filed
because registerMobileNetworkRequest checks with EntitlementManager
before actually requesting the network. If cellular becomes the
upstream and then later becomes not permitted because of an
entitlement failure, all tethering will be stopped by Settings.
Note: currently legacy upstream selection has two known bugs:
1. If mobile has higher priority than non-mobile network, mobile request
should never be released and always prefer use mobile. But in practice,
mobile request would be released when tethering select non-mobile network
as upstream.
2. If mobile has higher priority than wifi network and default network
is wifi but mobile is still connected, tethering would choose mobile as
upstream because it has higher priority. Mobile disconnecting may not
trigger tethering to switch its upstream to wifi because currnetly
tethering rely on CONNECTIVITY_ACTION broadcast to handle upstream
disconnect.
Bug: 173068192
Test: atest TetheringTests
Change-Id: Id5df58af830cc534ecd79041ddf8a04171047e9b
5 files changed