Android11 Wifi连接流程之IP地址分配

最新推荐文章于 2025-09-04 01:45:00 发布

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最新推荐文章于 2025-09-04 01:45:00 发布 · 3.8k 阅读

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#android #IP

本文详细介绍了Android 11中WiFi连接成功后IP地址的获取流程，从ClientModeImpl的startIpClient函数开始，经过Supplicant状态监听，到ObtainingIpState状态启动IPClient，最终进入RunningState进行IPv4和IPv6的配置。过程中涉及到DHCPClient的交互，以及如何处理静态和动态IP的情况。

在Android11 wifi连接流程中我们代码跟踪到了supplicant中开始associate，关联成功以后就是四次握手然后连接成功。连接成功以后还需要分配IP地址，才可以通信，这一节我们看一下IP地址的获取流程。

一、在ClientModeImpl中有一个函数startIpClient。这个函数会在俩个地方被调用，一个是连接的时候ConnectModeState，一个是连接成功以后进入ObtainingIpState。这俩个地方的区别就是isFilsConnection的不同，连接过程中isFilsConnection为true，把IPClinet先关掉。如果isFilsConnection为flase，则开始处理IP地址分配。
frameworks/opt/net/wifi/service/java/com/android/server/wifi/ClientModeImpl.java
这里我们先看是怎么进入ObtainingIpState的
SupplicantStaIfaceHal中注册了一个Supplicant的回调函数，当supplicant的状态发生改变时这里就会监听到，然后WifiMonitor就会发送statechange的广播。

private class SupplicantVendorStaIfaceHalCallback extends ISupplicantVendorStaIfaceCallback.Stub {
   
   
    private String mIfaceName;
    private SupplicantStaIfaceHalCallback mSupplicantStaIfacecallback;

    SupplicantVendorStaIfaceHalCallback(@NonNull String ifaceName, SupplicantStaIfaceHalCallback callback) {
   
   
        mIfaceName = ifaceName;
        mSupplicantStaIfacecallback = callback;
    }

    @Override
    public void onVendorStateChanged(int newState, byte[/* 6 */] bssid, int id,
                               ArrayList<Byte> ssid, boolean filsHlpSent) {
   
   
        synchronized (mLock) {
   
   
            logCallback("onVendorStateChanged");
            SupplicantState newSupplicantState =
                SupplicantStaIfaceCallbackImpl.supplicantHidlStateToFrameworkState(newState);
            WifiSsid wifiSsid = // wifigbk++
                    WifiGbk.createWifiSsidFromByteArray(NativeUtil.byteArrayFromArrayList(ssid));
            String bssidStr = NativeUtil.macAddressFromByteArray(bssid);
            if (newSupplicantState == SupplicantState.COMPLETED) {
   
   
                mWifiMonitor.broadcastNetworkConnectionEvent(
                        mIfaceName, getCurrentNetworkId(mIfaceName), filsHlpSent, bssidStr);
            }
            mWifiMonitor.broadcastSupplicantStateChangeEvent(
                    mIfaceName, getCurrentNetworkId(mIfaceName), wifiSsid, bssidStr, newSupplicantState);
        }
    }

frameworks/opt/net/wifi/service/java/com/android/server/wifi/WifiMonitor.java

public void broadcastNetworkConnectionEvent(String iface, int networkId, boolean filsHlpSent,
        String bssid) {
   
   
    sendMessage(iface, NETWORK_CONNECTION_EVENT, networkId, filsHlpSent ? 1 : 0, bssid);
}

此时wifi状态机还在ConnectModeState，对于NETWORK_CONNECTION_EVENT的处理结果就是跳转到ObtainingIpState

case WifiMonitor.NETWORK_CONNECTION_EVENT:
    if (mVerboseLoggingEnabled) log("Network connection established");
    mLastNetworkId = message.arg1;
    mSentHLPs = message.arg2 == 1;
    if (mSentHLPs) mWifiMetrics.incrementL2ConnectionThroughFilsAuthCount();
    mWifiConfigManager.clearRecentFailureReason(mLastNetworkId);
    mLastBssid = (String) message.obj;
    reasonCode = message.arg2;
    // TODO: This check should not be needed after ClientModeImpl refactor.
    // Currently, the last connected network configuration is left in
    // wpa_supplicant, this may result in wpa_supplicant initiating connection
    // to it after a config store reload. Hence the old network Id lookups may not
    // work, so disconnect the network and let network selector reselect a new
    // network.
    config = getCurrentWifiConfiguration();
    if (config != null) {
   
   
        if (mWifiConfigManager.saveAutoConnectedNewNetwork(config.networkId)) {
   
   
            Log.i(TAG, "Successfully connected to new network " + config.getPrintableSsid());
            mAutoConnectNewNetworkResultNotifier.onConnectionAttemptSuccess(config.SSID);
        }
        mWifiInfo.setBSSID(mLastBssid);
        mWifiInfo.setNetworkId(mLastNetworkId);
        mWifiInfo.setMacAddress