Android 11 WiFi MAC Randomization

开启未连接

ClientModeImpl

service/java/com/android/server/wifi/ClientModeImpl.java

setupClientMode

3637         if (isConnectedMacRandomizationEnabled()) {
3638             mWifiNative.setMacAddress(mInterfaceName, MacAddressUtils.createRandomUnicastAddress());
3639         }

 打开WLAN，但不连接，关闭再打开WiFi MAC地址会变。

连接

更新MAC地址

updateWifiConfigOnStartConnection

连接时根据设置里的配置更新MAC地址，“网络详情"-》"高级”-》“隐私”，使用随机MAC(默认)，使用设备MAC。

Network & internet -》WiFi -》Netowrk details -》Privacy:Use randomized MAC (default)、Use device MAC

6378     /**
6379      * Update the wifi configuration before sending connect to
6380      * supplicant/driver.
6381      *
6382      * @param config wifi configuration object.
6383      * @param bssid BSSID to assocaite with.
6384      */
6385     void updateWifiConfigOnStartConnection(WifiConfiguration config, String bssid) {


6470         if (isConnectedMacRandomizationEnabled()) {
6471             if (config.macRandomizationSetting == WifiConfiguration.RANDOMIZATION_PERSISTENT) {
6472                 configureRandomizedMacAddress(config);
6473             } else {
6474                 setCurrentMacToFactoryMac(config);
6475             }
6476         }

 使用随机MAC(默认)

configureRandomizedMacAddress

配置随机MAC地址。

3301      * Dynamically change the MAC address to use the locally randomized
3302      * MAC address generated for each network.
3303      * @param config WifiConfiguration with mRandomizedMacAddress to change into. If the address
3304      * is masked out or not set, it will generate a new random MAC address.
3305      */
3306     private void configureRandomizedMacAddress(WifiConfiguration config) {
3307         if (config == null) {
3308             Log.e(TAG, "No config to change MAC address to");
3309             return;
3310         }
3311         String currentMacString = mWifiNative.getMacAddress(mInterfaceName);
3312         MacAddress currentMac = currentMacString == null ? null :
3313                 MacAddress.fromString(currentMacString);
3314         MacAddress newMac = mWifiConfigManager.getRandomizedMacAndUpdateIfNeeded(config);
3315         if (!WifiConfiguration.isValidMacAddressForRandomization(newMac)) {
3316             Log.wtf(TAG, "Config generated an invalid MAC address");
3317         } else if (newMac.equals(currentMac)) {
3318             Log.d(TAG, "No changes in MAC address");
3319         } else {
3320             mWifiMetrics.logStaEvent(StaEvent.TYPE_MAC_CHANGE, config);
3321             boolean setMacSuccess =
3322                     mWifiNative.setMacAddress(mInterfaceName, newMac);
3323             if (setMacSuccess) {
3324                 mWifiNative.removeNetworkCachedDataIfNeeded(config.networkId, newMac);
3325             }
3326             Log.d(TAG, "ConnectedMacRandomization SSID(" + config.getPrintableSsid()
3327                     + "). setMacAddress(" + newMac.toString() + ") from "
3328                     + currentMacString + " = " + setMacSuccess);
3329         }
3330     }

获取随机MAC地址

getRandomizedMacAndUpdateIfNeeded

 enhanced_mac_randomization_force_enabled=1按需更新MAC地址。

 573     /**
 574      * Returns the randomized MAC address that should be used for this WifiCo