I have a wifi LAN setup which does not have internet access. Just various other local wifi devices connected to it. The DHCP is configured to not return a gateway or dns server. Only an IP and netmask.
When I connect my android to this wifi AP it connects fine, but all internet connectivity on the phone stops working.
I would expect that since the wifi has no gateway setting that android should realize the internet can't go through that connection and should instead be routed through the 3G connection which is at 5 bars.
I've tried setting a static IP on the android phone as well, but this did not help.
The main reason for this setup is so that the android device can transfer data on this remote network to an internet based server since it can connect to the local devices without issue. However the 3G side is broken once the wifi is setup.
Any thoughts on how to work around this issue?
After a bit of coding and testing I have merged Squonk and this solution. This is the class I have created:
package it.helian.exampleprj.network;
import java.net.InetAddress;
import java.net.UnknownHostException;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo.State;
import android.net.wifi.WifiManager;
import android.text.TextUtils;
import android.util.Log;
public class NetworkUtils {
private static final String TAG_LOG = "ExamplePrj";
Context context;
WifiManager wifiMan = null;
WifiManager.WifiLock wifiLock = null;
public NetworkUtils(Context context) {
super();
this.context = context;
}
/**
* Enable mobile connection for a specific address
* @param context a Context (application or activity)
* @param address the address to enable
* @return true for success, else false
*/
public boolean forceMobileConnectionForAddress(Context context, String address) {
ConnectivityManager connectivityManager = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
if (null == connectivityManager) {
Log.d(TAG_LOG, "ConnectivityManager is null, cannot try to force a mobile connection");
return false;
}
//check if mobile connection is available and connected
State state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
Log.d(TAG_LOG, "TYPE_MOBILE_HIPRI network state: " + state);
if (0 == state.compareTo(State.CONNECTED) || 0 == state.compareTo(State.CONNECTING)) {
return true;
}
//activate mobile connection in addition to other connection already activated
int resultInt = connectivityManager.startUsingNetworkFeature(ConnectivityManager.TYPE_MOBILE, "enableHIPRI");
Log.d(TAG_LOG, "startUsingNetworkFeature for enableHIPRI result: " + resultInt);
//-1 means errors
// 0 means already enabled
// 1 means enabled
// other values can be returned, because this method is vendor specific
if (-1 == resultInt) {
Log.e(TAG_LOG, "Wrong result of startUsingNetworkFeature, maybe problems");
return false;
}
if (0 == resultInt) {
Log.d(TAG_LOG, "No need to perform additional network settings");
return true;
}
//find the host name to route
String hostName = extractAddressFromUrl(address);
Log.d(TAG_LOG, "Source address: " + address);
Log.d(TAG_LOG, "Destination host address to route: " + hostName);
if (TextUtils.isEmpty(hostName)) hostName = address;
//create a route for the specified address
int hostAddress = lookupHost(hostName);
if (-1 == hostAddress) {
Log.e(TAG_LOG, "Wrong host address transformation, result was -1");
return false;
}
//wait some time needed to connection manager for waking up
try {
for (int counter=0; counter<30; counter++) {
State checkState = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
if (0 == checkState.compareTo(State.CONNECTED))
break;
Thread.sleep(1000);
}
} catch (InterruptedException e) {
//nothing to do
}
boolean resultBool = connectivityManager.requestRouteToHost(ConnectivityManager.TYPE_MOBILE_HIPRI, hostAddress);
Log.d(TAG_LOG, "requestRouteToHost result: " + resultBool);
if (!resultBool)
Log.e(TAG_LOG, "Wrong requestRouteToHost result: expected true, but was false");
state = connectivityManager.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
Log.d(TAG_LOG, "TYPE_MOBILE_HIPRI network state after routing: " + state);
return resultBool;
}
/**
* This method extracts from address the hostname
* @param url eg. http://some.where.com:8080/sync
* @return some.where.com
*/
public String extractAddressFromUrl(String url) {
String urlToProcess = null;
//find protocol
int protocolEndIndex = url.indexOf("://");
if(protocolEndIndex>0) {
urlToProcess = url.substring(protocolEndIndex + 3);
} else {
urlToProcess = url;
}
// If we have port number in the address we strip everything
// after the port number
int pos = urlToProcess.indexOf(':');
if (pos >= 0) {
urlToProcess = urlToProcess.substring(0, pos);
}
// If we have resource location in the address then we strip
// everything after the '/'
pos = urlToProcess.indexOf('/');
if (pos >= 0) {
urlToProcess = urlToProcess.substring(0, pos);
}
// If we have ? in the address then we strip
// everything after the '?'
pos = urlToProcess.indexOf('?');
if (pos >= 0) {
urlToProcess = urlToProcess.substring(0, pos);
}
return urlToProcess;
}
/**
* Transform host name in int value used by {@link ConnectivityManager.requestRouteToHost}
* method
*
* @param hostname
* @return -1 if the host doesn't exists, elsewhere its translation
* to an integer
*/
private int lookupHost(String hostname) {
InetAddress inetAddress;
try {
inetAddress = InetAddress.getByName(hostname);
} catch (UnknownHostException e) {
return -1;
}
byte[] addrBytes;
int addr;
addrBytes = inetAddress.getAddress();
addr = ((addrBytes[3] & 0xff) << 24)
| ((addrBytes[2] & 0xff) << 16)
| ((addrBytes[1] & 0xff) << 8 )
| (addrBytes[0] & 0xff);
return addr;
}
@SuppressWarnings("unused")
private int lookupHost2(String hostname) {
InetAddress inetAddress;
try {
inetAddress = InetAddress.getByName(hostname);
} catch (UnknownHostException e) {
return -1;
}
byte[] addrBytes;
int addr;
addrBytes = inetAddress.getAddress();
addr = ((addrBytes[3] & 0xff) << 24)
| ((addrBytes[2] & 0xff) << 16)
| ((addrBytes[1] & 0xff) << 8 )
| (addrBytes[0] & 0xff);
return addr;
}
public Boolean disableWifi() {
wifiMan = (WifiManager) context.getSystemService(Context.WIFI_SERVICE);
if (wifiMan != null) {
wifiLock = wifiMan.createWifiLock(WifiManager.WIFI_MODE_SCAN_ONLY, "HelianRCAWifiLock");
}
return wifiMan.setWifiEnabled(false);
}
public Boolean enableWifi() {
Boolean success = false;
if (wifiLock != null && wifiLock.isHeld())
wifiLock.release();
if (wifiMan != null)
success = wifiMan.setWifiEnabled(true);
return success;
}
}
This is the usage:
boolean mobileRoutingEnabled = checkMobileInternetRouting();
if(!mobileRoutingEnabled) {
networkUtils.disableWifi();
try {
Thread.sleep(3000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
networkUtils.forceMobileConnectionForAddress(context, RCA_URL);
if(!mobileRoutingEnabled) {
networkUtils.enableWifi();
}
// This second check is for testing purpose
checkMobileInternetRouting();
return callWebService(RCA_COMPLETE_URL, _plate);
where checkMobileInternetRouting is:
private boolean checkMobileInternetRouting() {
ConnectivityManager cm = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE);
State state = cm.getNetworkInfo(ConnectivityManager.TYPE_MOBILE_HIPRI).getState();
return 0 == state.compareTo(State.CONNECTED) || 0 == state.compareTo(State.CONNECTING);
}
This is a bit hacky but works properly. The only problem is that this routing has got a timeout of few seconds (like 20-30) that forces you to execute the entire above procedure once more. Setting this timeout to a higher value would be very good.