From eac13f7677f5d48720eaa446001236436b2d5471 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bram=20Bonn=C3=A9?= <brambonne@google.com>
Date: Tue, 20 Oct 2020 11:07:54 +0200
Subject: Use EUI64 IPv6 link-local address generation only when randomizing
 MAC

When connected MAC address randomization is used, generate IPv6
link-local addresses using EUI64 with the per-network defined MAC
address.
Networks that do not use MAC address randomization keep using RFC7217
stable privacy address generation instead.

Bug: 154114734

Test: atest ClientModeImplTest
Test: atest WifiManagerTest
Test: Connect to network
Test: Set up hotspot
Test: Observe that IPv6 link-local address differs for two networks
using randomization
Test: Observe that stable-privacy link-local address is used for network
when not using randomization

Merged-In: Iefb027b17657031116e068bbccdb7b2231a65238
Merged-In: I0a59c750511aacddb38b19bf64b56fd18ff545c5
Merged-In: I4512b87459d036630925ca5ac5ea42179c42ea71
Change-Id: Ief51232b6a4c284331afba74f1fe467dd1b254c8
---
 .../com/android/server/wifi/WifiStateMachine.java     | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/service/java/com/android/server/wifi/WifiStateMachine.java b/service/java/com/android/server/wifi/WifiStateMachine.java
index 390a10238..994b0d048 100644
--- a/service/java/com/android/server/wifi/WifiStateMachine.java
+++ b/service/java/com/android/server/wifi/WifiStateMachine.java
@@ -4969,12 +4969,17 @@ public class WifiStateMachine extends StateMachine {
             final WifiConfiguration currentConfig = getCurrentWifiConfiguration();
             final boolean isUsingStaticIp =
                     (currentConfig.getIpAssignment() == IpConfiguration.IpAssignment.STATIC);
+            final boolean isUsingMacRandomization =
+                    currentConfig.macRandomizationSetting
+                            == WifiConfiguration.RANDOMIZATION_PERSISTENT
+                            && isConnectedMacRandomizationEnabled();
             if (mVerboseLoggingEnabled) {
                 final String key = currentConfig.configKey();
                 log("enter ObtainingIpState netId=" + Integer.toString(mLastNetworkId)
                         + " " + key + " "
                         + " roam=" + mIsAutoRoaming
-                        + " static=" + isUsingStaticIp);
+                        + " static=" + isUsingStaticIp
+                        + " randomMac=" + isUsingMacRandomization);
             }
 
             // Send event to CM & network change broadcast
@@ -5001,25 +5006,25 @@ public class WifiStateMachine extends StateMachine {
             if (!TextUtils.isEmpty(mTcpBufferSizes)) {
                 mIpClient.setTcpBufferSizes(mTcpBufferSizes);
             }
-            final IpClient.ProvisioningConfiguration prov;
+            final IpClient.ProvisioningConfiguration.Builder prov;
             if (!isUsingStaticIp) {
                 prov = IpClient.buildProvisioningConfiguration()
                             .withPreDhcpAction()
                             .withApfCapabilities(mWifiNative.getApfCapabilities(mInterfaceName))
                             .withNetwork(getCurrentNetwork())
                             .withDisplayName(currentConfig.SSID)
-                            .withRandomMacAddress()
-                            .build();
+                if (isUsingMacRandomization) {
+                    prov.withRandomMacAddress();
+                }
             } else {
                 StaticIpConfiguration staticIpConfig = currentConfig.getStaticIpConfiguration();
                 prov = IpClient.buildProvisioningConfiguration()
                             .withStaticConfiguration(staticIpConfig)
                             .withApfCapabilities(mWifiNative.getApfCapabilities(mInterfaceName))
                             .withNetwork(getCurrentNetwork())
-                            .withDisplayName(currentConfig.SSID)
-                            .build();
+                            .withDisplayName(currentConfig.SSID);
             }
-            mIpClient.startProvisioning(prov);
+            mIpClient.startProvisioning(prov.build());
             // Get Link layer stats so as we get fresh tx packet counters
             getWifiLinkLayerStats();
         }
-- 
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