Make the IP subnet persistent till reboot

Make the IP subnet persistent if it do not conflict with upstream.
It allow client to reuse its IP that usually reduce DHCP procedure.

Bug: 168169687
Test: atest TetheringTests
Change-Id: Iddc5304730dce7b11c5d124b7eddce057d752bbd

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/1432958

Change-Id: I60ed54651034f21ca1cd253d272ac3478881b4e0
Merged-In: Iddc5304730dce7b11c5d124b7eddce057d752bbd
(cherry picked from commit 177e2d8d1867d7e72d00c81d6fbbed756c9f0568)
4 files changed
tree: c0420833486d060be1569143eab7e4cc2f30c157
  1. Tethering/