First pass at USB Tethering.

bug:2281900
diff --git a/core/java/android/net/ConnectivityManager.java b/core/java/android/net/ConnectivityManager.java
index 30799ec..d435df5 100644
--- a/core/java/android/net/ConnectivityManager.java
+++ b/core/java/android/net/ConnectivityManager.java
@@ -116,6 +116,24 @@
             "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
      * default connections.
@@ -338,4 +356,48 @@
         }
         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;
+        }
+    }
 }
diff --git a/core/java/android/net/IConnectivityManager.aidl b/core/java/android/net/IConnectivityManager.aidl
index 9f59cce..caa3f2b 100644
--- a/core/java/android/net/IConnectivityManager.aidl
+++ b/core/java/android/net/IConnectivityManager.aidl
@@ -50,4 +50,12 @@
     boolean getBackgroundDataSetting();
 
     void setBackgroundDataSetting(boolean allowBackgroundData);
+
+    boolean tether(String iface);
+
+    boolean untether(String iface);
+
+    String[] getTetherableIfaces();
+
+    String[] getTetheredIfaces();
 }
diff --git a/core/java/android/os/INetworkManagementService.aidl b/core/java/android/os/INetworkManagementService.aidl
index e4ec098..f48f45f 100644
--- a/core/java/android/os/INetworkManagementService.aidl
+++ b/core/java/android/os/INetworkManagementService.aidl
@@ -140,7 +140,8 @@
      * Attaches a PPP server daemon to the specified TTY with the specified
      * local/remote addresses.
      */
-    void attachPppd(String tty, String localAddr, String remoteAddr);
+    void attachPppd(String tty, String localAddr, String remoteAddr, String dns1Addr,
+            String dns2Addr);
 
     /**
      * Detaches a PPP server daemon from the specified TTY.
diff --git a/core/java/android/provider/Settings.java b/core/java/android/provider/Settings.java
index 7128005..bacaf43 100644
--- a/core/java/android/provider/Settings.java
+++ b/core/java/android/provider/Settings.java
@@ -2944,6 +2944,13 @@
         public static final String MOUNT_UMS_NOTIFY_ENABLED = "mount_ums_notify_enabled";
 
         /**
+         * Whether or not a notification is displayed when a Tetherable interface is detected.
+         * (0 = false, 1 = true)
+         * @hide
+         */
+        public static final String TETHER_NOTIFY = "tether_notify";
+
+        /**
          * If nonzero, ANRs in invisible background processes bring up a dialog.
          * Otherwise, the process will be silently killed.
          * @hide
diff --git a/core/java/com/android/internal/app/TetherActivity.java b/core/java/com/android/internal/app/TetherActivity.java
new file mode 100644
index 0000000..2b93dbc
--- /dev/null
+++ b/core/java/com/android/internal/app/TetherActivity.java
@@ -0,0 +1,151 @@
+/*
+ * Copyright (C) 2007 Google Inc.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.internal.app;
+
+import android.app.AlertDialog;
+import android.content.BroadcastReceiver;
+import android.content.Context;
+import android.content.DialogInterface;
+import android.content.Intent;
+import android.content.IntentFilter;
+import android.net.ConnectivityManager;
+import android.os.Bundle;
+import android.os.Handler;
+import android.os.IMountService;
+import android.os.Message;
+import android.os.RemoteException;
+import android.os.ServiceManager;
+import android.widget.Toast;
+import android.util.Log;
+
+/**
+ * This activity is shown to the user for him/her to connect/disconnect a Tether
+ * connection.  It will display notification when a suitable connection is made
+ * to allow the tether to be setup.  A second notification will be show when a
+ * tether is active, allowing the user to manage tethered connections.
+ */
+public class TetherActivity extends AlertActivity implements
+        DialogInterface.OnClickListener {
+
+    private static final int POSITIVE_BUTTON = AlertDialog.BUTTON1;
+
+    /* Used to detect when the USB cable is unplugged, so we can call finish() */
+    private BroadcastReceiver mTetherReceiver = new BroadcastReceiver() {
+        @Override
+        public void onReceive(Context context, Intent intent) {
+            if (intent.getAction() == ConnectivityManager.ACTION_TETHER_STATE_CHANGED) {
+                handleTetherStateChanged(intent);
+            }
+        }
+    };
+
+    private boolean mWantTethering;
+
+    @Override
+    protected void onCreate(Bundle savedInstanceState) {
+        super.onCreate(savedInstanceState);
+
+        // determine if we advertise tethering or untethering
+        ConnectivityManager cm =
+                (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
+        if (cm.getTetheredIfaces().length > 0) {
+            mWantTethering = false;
+        } else if (cm.getTetherableIfaces().length > 0) {
+            mWantTethering = true;
+        } else {
+            finish();
+            return;
+        }
+
+        // Set up the "dialog"
+        if (mWantTethering == true) {
+            mAlertParams.mIconId = com.android.internal.R.drawable.ic_dialog_usb;
+            mAlertParams.mTitle = getString(com.android.internal.R.string.tether_title);
+            mAlertParams.mMessage = getString(com.android.internal.R.string.tether_message);
+            mAlertParams.mPositiveButtonText =
+                    getString(com.android.internal.R.string.tether_button);
+            mAlertParams.mPositiveButtonListener = this;
+            mAlertParams.mNegativeButtonText =
+                    getString(com.android.internal.R.string.tether_button_cancel);
+            mAlertParams.mNegativeButtonListener = this;
+        } else {
+            mAlertParams.mIconId = com.android.internal.R.drawable.ic_dialog_usb;
+            mAlertParams.mTitle = getString(com.android.internal.R.string.tether_stop_title);
+            mAlertParams.mMessage = getString(com.android.internal.R.string.tether_stop_message);
+            mAlertParams.mPositiveButtonText =
+                    getString(com.android.internal.R.string.tether_stop_button);
+            mAlertParams.mPositiveButtonListener = this;
+            mAlertParams.mNegativeButtonText =
+                    getString(com.android.internal.R.string.tether_stop_button_cancel);
+            mAlertParams.mNegativeButtonListener = this;
+        }
+        setupAlert();
+    }
+
+    @Override
+    protected void onResume() {
+        super.onResume();
+
+        registerReceiver(mTetherReceiver, new IntentFilter(
+                ConnectivityManager.ACTION_TETHER_STATE_CHANGED));
+    }
+
+    @Override
+    protected void onPause() {
+        super.onPause();
+
+        unregisterReceiver(mTetherReceiver);
+    }
+
+    /**
+     * {@inheritDoc}
+     */
+    public void onClick(DialogInterface dialog, int which) {
+
+        if (which == POSITIVE_BUTTON) {
+            ConnectivityManager connManager =
+                    (ConnectivityManager)getSystemService(Context.CONNECTIVITY_SERVICE);
+            // start/stop tethering
+            if (mWantTethering) {
+                if (!connManager.tether("ppp0")) {
+                    showTetheringError();
+                }
+            } else {
+                if (!connManager.untether("ppp0")) {
+                    showUnTetheringError();
+                }
+            }
+        }
+        // No matter what, finish the activity
+        finish();
+    }
+
+    private void handleTetherStateChanged(Intent intent) {
+        finish();
+    }
+
+    private void showTetheringError() {
+        Toast.makeText(this, com.android.internal.R.string.tether_error_message,
+                Toast.LENGTH_LONG).show();
+    }
+
+    private void showUnTetheringError() {
+        Toast.makeText(this, com.android.internal.R.string.tether_stop_error_message,
+                Toast.LENGTH_LONG).show();
+    }
+
+}