WiFi and Ethernet coexist in Android

Open the following file from Android framework.

    - /android/frameworks/base/services/java/com/android/server/ConnectivityService.java
    
    - Add below code at appropriate place.
    
    // the set of network types that can only be enabled by system/sig apps
    List mProtectedNetworks;
    +// Wifi/Eth coexist strategy V0.3
    +private NetworkInfo mSecondaryNetworkInfo = null;
    +private int mActiveSecondaryNetwork = -1;
    +// End
    
    - Go to "handleDisconnect" function. Add below code at appropriate place.
    
    int prevNetType = info.getType();

    +// Wifi/Eth coexist strategy V0.3
    +if (prevNetType == ConnectivityManager.TYPE_WIFI) {
    +    log("Wifi Disconnected!");
    +    mSecondaryNetworkInfo = null;
    +    mActiveSecondaryNetwork = -1;
    +}
    +// End
    
    ...
    
    if (mActiveDefaultNetwork != -1) {
            sendConnectedBroadcastDelayed(mNetTrackers[mActiveDefaultNetwork].getNetworkInfo(),
                    getConnectivityChangeDelay());
    }

    +// Wifi/Eth coexist strategy V0.3
    +if (prevNetType == ConnectivityManager.TYPE_ETHERNET && mActiveSecondaryNetwork != -1) {
    +    log("Ethernet disconnect, refresh netowrk info to wifi.");
    +    handleConnect(mSecondaryNetworkInfo);
    +    log("Add wlan0 default route info");
    +    LinkProperties wifiLp = mNetTrackers[mActiveDefaultNetwork].getLinkProperties();
    +    String ifname = wifiLp.getInterfaceName();
    +    for(RouteInfo r : wifiLp.getRoutes()) {
    +        try {
    +            if (r.isDefaultRoute()) {
    +                log(ifname + "add default route: " + r);
    +                mNetd.addRoute(ifname, r);
    +            }
    +        } catch (Exception e) {
    +            // never crash - catch them all
    +            if (DBG) loge("Exception trying to remove a route: " + e);
    +            //return false;
    +        }
    +    }
    +}
    +// End
    
    - Go to "handleConnectionFailure" function. Add below code at appropriate place.
    
    mNetTrackers[info.getType()].setTeardownRequested(false);

    +// Wifi/Eth coexist strategy V0.3
    +if (info.getType() == ConnectivityManager.TYPE_WIFI) {
    +    log("Wifi Disconnected!");
    +    mSecondaryNetworkInfo = null;
    +    mActiveSecondaryNetwork = -1;
    +}
    +// End
    
    ...
    
    if (mActiveDefaultNetwork != -1) {
        sendConnectedBroadcast(mNetTrackers[mActiveDefaultNetwork].getNetworkInfo());
    }

    +// Wifi/Eth coexixt strategy V0.3
    +if (info.getType() == ConnectivityManager.TYPE_ETHERNET && mActiveSecondaryNetwork != -1) {
    +    log("Ethernet disconnect, refresh netowrk info to wifi.[handleConnectionFailure]");
    +    handleConnect(mSecondaryNetworkInfo);
    +    log("Add wlan0 default route info[handleConnectionFailure]");
    +    LinkProperties wifiLp = mNetTrackers[mActiveDefaultNetwork].getLinkProperties();
    +    String ifname = wifiLp.getInterfaceName();
    +    for(RouteInfo r : wifiLp.getRoutes()) {
    +        try {
    +            if (r.isDefaultRoute()) {
    +                log(ifname + "add default route: " + r);
    +                mNetd.addRoute(ifname, r);
    +            }
    +        } catch (Exception e) {
    +            // never crash - catch them all
    +            if (DBG) loge("Exception trying to remove a route: " + e);
    +            //return false;
    +        }
    +    }
    +}
    +// End
    
    - Go to "handleConnect" function. Add below code at appropriate place.
    
    final int newNetType = info.getType();

    +// Wifi/Eth coexist strategy V0.3
    +log("Connected type: " + newNetType);
    +log("Current preferred type: " + mNetworkPreference);
    +// End
    
    ...
    
    // if this is a default net and other default is running
    // kill the one not preferred
    if (mNetConfigs[newNetType].isDefault()) {
        if (mActiveDefaultNetwork != -1 && mActiveDefaultNetwork != newNetType) {
            if (isNewNetTypePreferredOverCurrentNetType(newNetType)) {
                +// Wifi/Eth coexist strategy V0.3
                +if (newNetType == ConnectivityManager.TYPE_ETHERNET &&
                +        mActiveDefaultNetwork == ConnectivityManager.TYPE_WIFI) {
                +    log("Wifi already connected, but Eth connected after. Eth&Wifi coexit");
                +    mSecondaryNetworkInfo = mNetTrackers[ConnectivityManager.TYPE_WIFI].getNetworkInfo();;
                +    mActiveSecondaryNetwork = mActiveDefaultNetwork;
                +    log("Delete wlan0 default route info");
                +    LinkProperties wifiLp = mNetTrackers[mActiveDefaultNetwork].getLinkProperties();
                +    String ifname = wifiLp.getInterfaceName();
                +    for(RouteInfo r : wifiLp.getRoutes()) {
                +        try {
                +            if (r.isDefaultRoute()) {
                +                log(ifname + "remove default route: " + r);
                +                mNetd.removeRoute(ifname, r);
                +            }
                +        } catch (Exception e) {
                +            // never crash - catch them all
                +            if (DBG) loge("Exception trying to remove a route: " + e);
                +            //return false;
                +        }

                +    }
                +} else {
                +    // tear down the other
                +    NetworkStateTracker otherNet = mNetTrackers[mActiveDefaultNetwork];
                +    if (DBG) {
                +        log("Policy requires " + otherNet.getNetworkInfo().getTypeName() +
                +               " teardown");
                +    }
                +    if (!teardown(otherNet)) {
                +        loge("Network declined teardown request");
                +        teardown(thisNet);
                +        return;
                +    }
                +}
                +// End
            } else {
                +// Wifi/Eth coexist strategy V0.3
                +if (newNetType == ConnectivityManager.TYPE_WIFI &&
                +        mActiveDefaultNetwork == ConnectivityManager.TYPE_ETHERNET) {
                +    mSecondaryNetworkInfo = info;
                +    mActiveSecondaryNetwork = newNetType;
                +    log("Eth already connected, but wifi connected after. Eth&Wifi coexist.");
                +    log("Eth default active \t Wifi seconday active");
                +    return;
                +} else {
                +    // don't accept this one
                +    if (VDBG) {
                +        log("Not broadcasting CONNECT_ACTION " +
                +            "to torn down network " + info.getTypeName());
                +    }
                +    teardown(thisNet);
                +    return;
                +}
                +// End
            }
        }
        synchronized (ConnectivityService.this) {
            // have a new default network, release the transition wakelock in a second
            // if it's held.  The second pause is to allow apps to reconnect over the
            // new network
            if (mNetTransitionWakeLock.isHeld()) {
                mHandler.sendMessageDelayed(mHandler.obtainMessage(
                       EVENT_CLEAR_NET_TRANSITION_WAKELOCK,
                        mNetTransitionWakeLockSerialNumber, 0),
                        1000);
            }
        }
        mActiveDefaultNetwork = newNetType;
        // this will cause us to come up initially as unconnected and switching
        // to connected after our normal pause unless somebody reports us as reall
        // disconnected
        mDefaultInetConditionPublished = 0;
        mDefaultConnectionSequence++;
        mInetConditionChangeInFlight = false;
        // Don't do this - if we never sign in stay, grey
        //reportNetworkCondition(mActiveDefaultNetwork, 100);
    }
    
    - Go to "handleCaptivePortalTrackerCheck" function. Add below code at appropriate place.
    
    if (DBG) log("Tear down low priority net " + info.getTypeName());

    +// Wifi/Eth coexist strategy V0.3
    +//teardown(thisNet);
    +if (mActiveDefaultNetwork == ConnectivityManager.TYPE_ETHERNET)
    +     mCaptivePortalTracker.detectCaptivePortal(new NetworkInfo(info));
    +// End
    return;
    
    
    

Hello Dharmesh Patel, I am facing the same problem. I would like to have two connections, one wifi and one ethernet.

You had a great fix here. The problem is, that I have to use Android 9 and there were some changes in the code. Could you please help me to map your fix to Android 9 code?

Thanks for your awesome fix anyway :)

Best regards, Tobias.

Hello @tobias,

I will check for Android 9.0. I will update you in few days.

Hello Dharmesh Patel, I am facing the same problem. I would like to have two connections, one wifi and one ethernet.
You had a great fix here. The problem is, that I have to use Android 9 and there were some changes in the code. Could you please help me to map your fix to Android 9 code?
Thanks for your awesome fix anyway :)
Best regards, Tobias.

Hello @tobias,

I will check for Android 9.0. I will update you in few days.

Hello @tovias,

Please refer below link and try it.
https://www.fatalerrors.org/a/android-8.1-and-android-5.1-are-connected-via-ethernet.html

Hello @dmpatel151282,

thanks for your fast reply. I will try solving the problem using the link you offered and give an update :)

Hello @dmpatel151282

I made the changes according to the guide, but it doesnt seem to fix my problem. The change of network score seems to work, because if I am connected to ethernet and turn on wifi, ethernet turns off and wifi gets connected. The problem is, that ethernet gets disconnected if I turn on wifi and only gets connected if I turn off wifi. So I am connected to ethernet, wifi off -> turn on wifi, disconnected from ethernet and connected to wifi -> turn wifi off, disconnected from wifi and connected to ethernet.

Thanks for your help
Best regards, Tobias

Hello @dmpatel151282

I made the changes according to the guide, but it doesnt seem to fix my problem. The change of network score seems to work, because if I am connected to ethernet and turn on wifi, ethernet turns off and wifi gets connected. The problem is, that ethernet gets disconnected if I turn on wifi and only gets connected if I turn off wifi. So I am connected to ethernet, wifi off -> turn on wifi, disconnected from ethernet and connected to wifi -> turn wifi off, disconnected from wifi and connected to ethernet.

Thanks for your help
Best regards, Tobias

Hello @TobianVorsmann

I have checked in Android Q based device and Ethernet and WiFi are running at same time.

I will look into it for changes in Android 9 and Android Q. Can you please check parallelly to get solution???

Hello @dmpatel151282

Thanks for your help. I am trying to find a solution parallelly for sure :)

Hello @TobianVorsmann

Have you got any solution of it???

If not then add below patch line in frameworks/base/services/core/java/com/android/server/ConnectivityService.java file.

+ final NetworkRequest mEthernetRequest = createDefaultInternetRequestForTransport(
+                                                 NetworkCapabilities.TRANSPORT_ETHERNET,
+                                                 NetworkRequest.Type.REQUEST);
+           NetworkRequestInfo ethernetNRI = new NetworkRequestInfo(null, mEthernetRequest, new Binder());
+           mNetworkRequests.put(mEthernetRequest, ethernetNRI);
+           mNetworkRequestInfoLogs.log("REGISTER " + ethernetNRI); 

mDefaultMobileDataRequest = createDefaultInternetRequestForTransport(
  | NetworkCapabilities.TRANSPORT_CELLULAR, NetworkRequest.Type.BACKGROUND_REQUEST);

I have tried in Android Q and it's working.