Android-双网络实现

原本很早就想把这些东西写文章保留下来，但是只怪自己真的太懒啦，2年后的今天才开始整理当时工作时的思路

背景

借助Android 4G ，WiFi 双网络模式可以互补，大大的提高应用的稳定性
作为一款工具类产品，WiFi，4G流量，使我们的业务重心，如何将4G & WiFi
彻底打通，为用户提供更沉浸式的服务体验，使我们一直以来的最求

思路

非常感谢国外的一款产品，在实现上为我们提供了一个入门的思路 speedify

no bb show my code
如果有人感兴趣这个实现过程，可以单独来交流

具体实现方案

准备工作：
1. 此方案借助了VPN来实现本地流量的劫持，并控制发送网络通道
2. 因为Android版本的差异性，实现方案也将按照高低不同版本来设计
3. 因为现在手上已经没有那么多资源，所以更多的是代码和思路讲解，如果你感兴趣可能需要自己做一部分前置工作
  eg： VPN 搭建，后台配套服务

基本实现思路

API < 6.0

启动Android手机高速网卡，在启动成功后将高速网卡和 VPN出口IP绑定

  public class SetupHIPRIEnableTask extends TimerTask {

    private static final String TAG = "SetupHIPRIEnableTask\t";

    private Context mContext;

    public SetupHIPRIEnableTask(Context context) {
        mContext = context;
    }

    @Override
    public void run() {
        try {
            DLog.i(TAG + "Polling mobile network to make sure it stays up");
            ConnectivityManager connectivityManager = (ConnectivityManager) mContext
                    .getSystemService(CONNECTIVITY_SERVICE);
            if (connectivityManager == null) {
                Log.e(TAG, "ConnectivityManager is null, cannot try to force a mobile connection");
            } else if (connectivityManager.getNetworkInfo(5) == null) {
                Log.e(TAG, "Mobile Interface Not Found.");
            } else {
                int startUsingNetworkFeature = connectivityManager.startUsingNetworkFeature(0, "enableHIPRI");
                Log.d(TAG, "startUsingNetworkFeature for enableHIPRI result: " + startUsingNetworkFeature);
                if (-1 == startUsingNetworkFeature) {
                    Log.e(TAG, "Wrong result of startUsingNetworkFeature, maybe problems");
                }
                if (connectivityManager.getNetworkInfo(5).getState().compareTo(NetworkInfo.State.CONNECTED) == 0) {
                    Log.d(TAG, "Mobile network is connected");
                } else {
                    Log.d(TAG, "Mobile network is not connected");
                }
            }
            requestRouteToHost();
        } catch (Exception e) {
            Log.e(TAG, "Hit error in KeepMobileAliveTask ", e);
        }
    }

    /**
     * 等待 ： TYPE_MOBILE_HIPRI类型的网络建立连接后
     * <p/>
     * deliver traffic to the specified host via the specified network interface
     */
    private void requestRouteToHost() {
        String ip = AuthDataManager.getInstance().getAuthData().getIp();
        int i = AppUtil.convertIpToInt(ip);
        ConnectivityManager connectivityManager = (ConnectivityManager) mContext.getSystemService(CONNECTIVITY_SERVICE);
        if (connectivityManager == null) {
            DLog.i(TAG + "ConnectivityManager is null, cannot try to force a mobile connection");
        } else if (connectivityManager.getNetworkInfo(5) == null) {
            DLog.i(TAG + "Mobile Interface Not Found.");
        } else {
            int i2 = 0;
            while (i2 < 20) {
                try {
                    if (connectivityManager.getNetworkInfo(5).getState().compareTo(NetworkInfo.State.CONNECTED) == 0) {
                        break;
                    }
                    Thread.sleep(1000);
                    i2++;
                } catch (InterruptedException ignored) {
                }
            }
            DLog.i(TAG + "requestRouteToHost result: " + connectivityManager.requestRouteToHost(5, i));
        }
    }

}

API >= 6.0

通过Android标准API在WiFi连接的情况下，请求4G网络通道，

当4G网络通道成功后，Android会回调一个networkId ，

通过NDK将此networkId与VPN的上网了进程绑定，从而实现走VPN的数据流量都通过4G 网络

public void requestWorkNetForHigh(Context context) {
        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
        if (cm == null) {
            DLog.i("ConnectivityManager is null, cannot try to force a mobile connection");
            return;
        }
        DLog.i("post50MobileEnable, requesting Cellular network");
        NetworkRequest.Builder builder = new NetworkRequest.Builder();
        builder.addTransportType(0);
        builder.addCapability(12);
        NetworkRequest build = builder.build();
        unregisterNetworkCallback();
        try {
            if (mNetWorkCallBack == null) {
                mNetWorkCallBack = new MNetWorkCallBack();
            }
            DLog.i("Requesting Connectivity Manager");
            cm.requestNetwork(build, mNetWorkCallBack);
        } catch (SecurityException e) {
            DLog.i("com.speedify.speedifyAndroid.MobileController Cannot write settings. Requesting Permission");

        } catch (Exception e2) {
            DLog.e("Unknown Exception", e2);
            e2.printStackTrace();
        }
    }

  private class MNetWorkCallBack extends ConnectivityManager.NetworkCallback {

        @Override
        public void onAvailable(Network network) {
            DLog.i(TAG + "NetWorkCallBack " + network);
            super.onAvailable(network);
        }
    }

POC当时的技术结论：

技术POC测试结论

--未完待补充