First pass at USB Tethering.

bug:2281900

core/java/android/net/ConnectivityManager.java

@@ -115,6 +115,24 @@ public class ConnectivityManager
     public static final String ACTION_BACKGROUND_DATA_SETTING_CHANGED =
             "android.net.conn.BACKGROUND_DATA_SETTING_CHANGED";
 
+    /**
+     * Broadcast Action: A tetherable connection has come or gone
+     * TODO - finish the doc
+     * @hide
+     */
+    public static final String ACTION_TETHER_STATE_CHANGED =
+            "android.net.conn.TETHER_STATE_CHANGED";
+
+    /**
+     * @hide
+     */
+    public static final String EXTRA_AVAILABLE_TETHER_COUNT = "availableCount";
+
+    /**
+     * @hide
+     */
+    public static final String EXTRA_ACTIVE_TETHER_COUNT = "activeCount";
+
     /**
      * The Default Mobile data connection.  When active, all data traffic
      * will use this connection by default.  Should not coexist with other
@@ -338,4 +356,48 @@ public class ConnectivityManager
         }
         mService = service;
     }
+
+    /**
+     * {@hide}
+     */
+    public String[] getTetherableIfaces() {
+        try {
+            return mService.getTetherableIfaces();
+        } catch (RemoteException e) {
+            return new String[0];
+        }
+    }
+
+    /**
+     * {@hide}
+     */
+    public String[] getTetheredIfaces() {
+        try {
+            return mService.getTetheredIfaces();
+        } catch (RemoteException e) {
+            return new String[0];
+        }
+    }
+
+    /**
+     * {@hide}
+     */
+    public boolean tether(String iface) {
+        try {
+            return mService.tether(iface);
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
+
+    /**
+     * {@hide}
+     */
+    public boolean untether(String iface) {
+        try {
+            return mService.untether(iface);
+        } catch (RemoteException e) {
+            return false;
+        }
+    }
 }

core/java/android/net/IConnectivityManager.aidl

@@ -50,4 +50,12 @@ interface IConnectivityManager
     boolean getBackgroundDataSetting();
 
     void setBackgroundDataSetting(boolean allowBackgroundData);
+
+    boolean tether(String iface);
+
+    boolean untether(String iface);
+
+    String[] getTetherableIfaces();
+
+    String[] getTetheredIfaces();
 }

services/java/com/android/server/ConnectivityService.java

@@ -43,6 +43,8 @@ import android.util.Log;
 
 import com.android.internal.telephony.Phone;
 
+import com.android.server.connectivity.Tethering;
+
 import java.io.FileDescriptor;
 import java.io.PrintWriter;
 import java.util.ArrayList;
@@ -62,6 +64,9 @@ public class ConnectivityService extends IConnectivityManager.Stub {
     private static final String NETWORK_RESTORE_DELAY_PROP_NAME =
             "android.telephony.apn-restore";
 
+
+    private Tethering mTethering;
+
     /**
      * Sometimes we want to refer to the individual network state
      * trackers separately, and sometimes we just want to treat them
@@ -308,6 +313,8 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 continue;
             }
         }
+
+        mTethering = new Tethering(mContext);
     }
 
 
@@ -784,6 +791,13 @@ public class ConnectivityService extends IConnectivityManager.Stub {
                 "ConnectivityService");
     }
 
+    // TODO Make this a special check when it goes public
+    private void enforceTetherChangePermission() {
+        mContext.enforceCallingOrSelfPermission(
+                android.Manifest.permission.CHANGE_NETWORK_STATE,
+                "ConnectivityService");
+    }
+
     /**
      * Handle a {@code DISCONNECTED} event. If this pertains to the non-active
      * network, we ignore it. If it is for the active network, we send out a
@@ -1368,4 +1382,28 @@ public class ConnectivityService extends IConnectivityManager.Stub {
             }
         }
     }
+
+    // javadoc from interface
+    public boolean tether(String iface) {
+        enforceTetherChangePermission();
+        return mTethering.tether(iface);
+    }
+
+    // javadoc from interface
+    public boolean untether(String iface) {
+        enforceTetherChangePermission();
+        return mTethering.untether(iface);
+    }
+
+    // TODO - move iface listing, queries, etc to new module
+    // javadoc from interface
+    public String[] getTetherableIfaces() {
+        enforceAccessPermission();
+        return mTethering.getTetherableIfaces();
+    }
+
+    public String[] getTetheredIfaces() {
+        enforceAccessPermission();
+        return mTethering.getTetheredIfaces();
+    }
 }