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

1 files changed, 4 insertions, 4 deletions

diff --git a/packages/Tethering/src/android/net/ip/IpServer.java b/packages/Tethering/src/android/net/ip/IpServer.java
index 336124dc1b90..52d59fcdc19b 100644
--- a/packages/Tethering/src/android/net/ip/IpServer.java
+++ b/packages/Tethering/src/android/net/ip/IpServer.java
@@ -616,7 +616,7 @@ public class IpServer extends StateMachine {
         if (VDBG) Log.d(TAG, "configureIPv4(" + enabled + ")");
 
         if (enabled) {
-            mIpv4Address = requestIpv4Address();
+            mIpv4Address = requestIpv4Address(true /* useLastAddress */);
         }
 
         if (mIpv4Address == null) {
@@ -661,14 +661,14 @@ public class IpServer extends StateMachine {
         return configureDhcp(enabled, mIpv4Address, mStaticIpv4ClientAddr);
     }
 
-    private LinkAddress requestIpv4Address() {
+    private LinkAddress requestIpv4Address(final boolean useLastAddress) {
         if (mStaticIpv4ServerAddr != null) return mStaticIpv4ServerAddr;
 
         if (mInterfaceType == TetheringManager.TETHERING_BLUETOOTH) {
             return new LinkAddress(BLUETOOTH_IFACE_ADDR);
         }
 
-        return mPrivateAddressCoordinator.requestDownstreamAddress(this);
+        return mPrivateAddressCoordinator.requestDownstreamAddress(this, useLastAddress);
     }
 
     private boolean startIPv6() {
@@ -957,7 +957,7 @@ public class IpServer extends StateMachine {
         }
 
         final LinkAddress deprecatedLinkAddress = mIpv4Address;
-        mIpv4Address = requestIpv4Address();
+        mIpv4Address = requestIpv4Address(false);
         if (mIpv4Address == null) {
             mLog.e("Fail to request a new downstream prefix");
             return;