Android 9

1.修改 frameworks/base/core/java/android/net/NetworkFactory.java

evalRequest 方法 注释两行

private void evalRequest(NetworkRequestInfo n) {if (VDBG) log("evalRequest");if (n.requested == false && n.score < mScore &&n.request.networkCapabilities.satisfiedByNetworkCapabilities(mCapabilityFilter) && acceptRequest(n.request, n.score)) {if (VDBG) log("  needNetworkFor");needNetworkFor(n.request, n.score);n.requested = true;Log.d(TAG, "needNetworkFor");} else if (n.requested == true &&(n.score > mScore || n.request.networkCapabilities.satisfiedByNetworkCapabilities(mCapabilityFilter) == false || acceptRequest(n.request, n.score) == false)) {if (VDBG) log("  releaseNetworkFor");Log.d(TAG, "releaseNetworkFor");//releaseNetworkFor(n.request);//注释//n.requested = false;//注释} else {if (VDBG) log("  done");}}

2.修改frameworks/opt/net/ethernet/java/com/android/server/ethernet/EthernetNetworkFactory.java文件修改 NETWORK_SCORE=30 降低优先级

这样以太网和wifi都能连接成功

Android 12 

frameworks\opt\net\ethernet\java\com\android\server\ethernet\EthernetNetworkFactory.java

需要修改下面的得分

private static final SparseArray<TransportInfo> sTransports = new SparseArray();static {// LowpanInterfaceTracker.NETWORK_SCOREsTransports.put(NetworkCapabilities.TRANSPORT_LOWPAN,new TransportInfo(ConnectivityManager.TYPE_NONE, 30));// WifiAwareDataPathStateManager.NETWORK_FACTORY_SCORE_AVAILsTransports.put(NetworkCapabilities.TRANSPORT_WIFI_AWARE,new TransportInfo(ConnectivityManager.TYPE_NONE, 1));// EthernetNetworkFactory.NETWORK_SCOREsTransports.put(NetworkCapabilities.TRANSPORT_ETHERNET,new TransportInfo(ConnectivityManager.TYPE_ETHERNET, 70));// BluetoothTetheringNetworkFactory.NETWORK_SCOREsTransports.put(NetworkCapabilities.TRANSPORT_BLUETOOTH,new TransportInfo(ConnectivityManager.TYPE_BLUETOOTH, 69));// WifiNetworkFactory.SCORE_FILTER / NetworkAgent.WIFI_BASE_SCOREsTransports.put(NetworkCapabilities.TRANSPORT_WIFI,new TransportInfo(ConnectivityManager.TYPE_WIFI, 60));// TelephonyNetworkFactory.TELEPHONY_NETWORK_SCOREsTransports.put(NetworkCapabilities.TRANSPORT_CELLULAR,new TransportInfo(ConnectivityManager.TYPE_MOBILE, 50));}

frameworks\libs\net\common\device\android\net\NetworkFactoryLegacyImpl.java

原因是updateAgent变了

Android 9

private void updateAgent() {if (mNetworkAgent == null) return;if (DBG) {Log.i(TAG, "Updating mNetworkAgent with: " +mCapabilities + ", " +mNetworkInfo + ", " +mLinkProperties);}mNetworkAgent.sendNetworkCapabilities(mCapabilities);mNetworkAgent.sendNetworkInfo(mNetworkInfo);mNetworkAgent.sendLinkProperties(mLinkProperties);// never set the network score below 0.mNetworkAgent.sendNetworkScore(mLinkUp? NETWORK_SCORE : 0);}

Android12

private void updateAgent() {if (mNetworkAgent == null) return;if (DBG) {Log.i(TAG, "Updating mNetworkAgent with: " +mCapabilities + ", " +mLinkProperties);}mNetworkAgent.sendNetworkCapabilities(mCapabilities);mNetworkAgent.sendLinkProperties(mLinkProperties);// As a note, getNetworkScore() is fairly expensive to calculate. This is fine for now// since the agent isn't updated frequently. Consider caching the score in the future if// agent updating is required more oftenmNetworkAgent.sendNetworkScore(getNetworkScore());}

/*** Determines the network score based on the transport associated with the interface.* Ethernet interfaces could propagate a transport types forward. Since we can't* get more information about the statuses of the interfaces on the other end of the local* interface, we'll best-effort assign the score as the base score of the assigned transport* when the link is up. When the link is down, the score is set to zero.** This function is called with the purpose of assigning and updating the network score of* the member NetworkAgent.*/private int getNetworkScore() {// never set the network score below 0.if (!mLinkUp) {return 0;}int[] transportTypes = mCapabilities.getTransportTypes();if (transportTypes.length < 1) {Log.w(TAG, "Network interface '" + mLinkProperties.getInterfaceName() + "' has no "+ "transport type associated with it. Score set to zero");return 0;}TransportInfo transportInfo = sTransports.get(transportTypes[0], /* if dne */ null);if (transportInfo != null) {return transportInfo.mScore;}return 0;}

所谓共存就是让两个网络同时使用，如果想让哪个网络作为外网，则该网络优先级要高于内网的网络，即可达到外网用来上网的需求，那么要想共存，就必须到从低优先级网络切换到优先级高的网络时，不要做断开操作，即可达到，两个网络同时存在的需求，做到以上两点，我们便满足了2个网络同时存在，且使用优先级高的外网上网

到了android12已经废弃了这种直接的打分机制，使用了policy机制，具体可参考
packages/modules/Connectivity/service/src/com/android/server/connectivity/NetworkRanker.java
但由于这种评分机制涉及的条件比较多，对于我们做网络共存这个需求来说更加复杂，
对此android开发者也给我么预留了以前的评分方案，只要我们简单的将
USE_POLICY_RANKING = false; 即可

 /*** Find the best network satisfying this request among the list of passed networks.*/@Nullablepublic NetworkAgentInfo getBestNetwork(@NonNull final NetworkRequest request,@NonNull final Collection<NetworkAgentInfo> nais,@Nullable final NetworkAgentInfo currentSatisfier) {final ArrayList<NetworkAgentInfo> candidates = filter(nais, nai -> nai.satisfies(request));if (candidates.size() == 1) return candidates.get(0); // Only one potential satisfierif (candidates.size() <= 0) return null; // No network can satisfy this requestif (USE_POLICY_RANKING) {return getBestNetworkByPolicy(candidates, currentSatisfier);} else {return getBestNetworkByLegacyInt(candidates);}}