From 07b8fe1f92529f1b7bb8bf613955586cfd21a0e5 Mon Sep 17 00:00:00 2001
From: Seungjae Yoo <seungjaeyoo@google.com>
Date: Wed, 19 Jun 2024 16:18:51 +0900
Subject: [PATCH] Introduce TETHERING_VIRTUAL type

Bug: 340376953
Test: Presubmit
Change-Id: I0714b62ebfc63fc966d7873ebdd68ae72c015bc4
---
 .../TetheringLib/api/system-current.txt       |  1 +
 .../src/android/net/TetheringManager.java     | 12 ++++++++++-
 .../networkstack/tethering/Tethering.java     | 20 +++++++++++++++++++
 common/flags.aconfig                          |  8 ++++++++
 4 files changed, 40 insertions(+), 1 deletion(-)

diff --git a/Tethering/common/TetheringLib/api/system-current.txt b/Tethering/common/TetheringLib/api/system-current.txt
index a287b428db..cccafd58d2 100644
--- a/Tethering/common/TetheringLib/api/system-current.txt
+++ b/Tethering/common/TetheringLib/api/system-current.txt
@@ -47,6 +47,7 @@ package android.net {
     field public static final int TETHERING_INVALID = -1; // 0xffffffff
     field public static final int TETHERING_NCM = 4; // 0x4
     field public static final int TETHERING_USB = 1; // 0x1
+    field @FlaggedApi("com.android.net.flags.tethering_request_virtual") public static final int TETHERING_VIRTUAL = 7; // 0x7
     field public static final int TETHERING_WIFI = 0; // 0x0
     field public static final int TETHERING_WIFI_P2P = 3; // 0x3
     field public static final int TETHER_ERROR_DHCPSERVER_ERROR = 12; // 0xc
diff --git a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
index 7b769d49fe..2963f87a36 100644
--- a/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
+++ b/Tethering/common/TetheringLib/src/android/net/TetheringManager.java
@@ -68,6 +68,8 @@ public class TetheringManager {
     public static class Flags {
         static final String TETHERING_REQUEST_WITH_SOFT_AP_CONFIG =
                 "com.android.net.flags.tethering_request_with_soft_ap_config";
+        static final String TETHERING_REQUEST_VIRTUAL =
+                "com.android.net.flags.tethering_request_virtual";
     }
 
     private static final String TAG = TetheringManager.class.getSimpleName();
@@ -194,11 +196,19 @@ public class TetheringManager {
      */
     public static final int TETHERING_WIGIG = 6;
 
+    /**
+     * VIRTUAL tethering type.
+     * @hide
+     */
+    @FlaggedApi(Flags.TETHERING_REQUEST_VIRTUAL)
+    @SystemApi
+    public static final int TETHERING_VIRTUAL = 7;
+
     /**
      * The int value of last tethering type.
      * @hide
      */
-    public static final int MAX_TETHERING_TYPE = TETHERING_WIGIG;
+    public static final int MAX_TETHERING_TYPE = TETHERING_VIRTUAL;
 
     /** @hide */
     @Retention(RetentionPolicy.SOURCE)
diff --git a/Tethering/src/com/android/networkstack/tethering/Tethering.java b/Tethering/src/com/android/networkstack/tethering/Tethering.java
index d85d92f15e..29ced23a16 100644
--- a/Tethering/src/com/android/networkstack/tethering/Tethering.java
+++ b/Tethering/src/com/android/networkstack/tethering/Tethering.java
@@ -38,6 +38,7 @@ import static android.net.TetheringManager.TETHERING_ETHERNET;
 import static android.net.TetheringManager.TETHERING_INVALID;
 import static android.net.TetheringManager.TETHERING_NCM;
 import static android.net.TetheringManager.TETHERING_USB;
+import static android.net.TetheringManager.TETHERING_VIRTUAL;
 import static android.net.TetheringManager.TETHERING_WIFI;
 import static android.net.TetheringManager.TETHERING_WIFI_P2P;
 import static android.net.TetheringManager.TETHERING_WIGIG;
@@ -278,6 +279,7 @@ public class Tethering {
     private TetheredInterfaceRequestShim mBluetoothIfaceRequest;
     private String mConfiguredEthernetIface;
     private String mConfiguredBluetoothIface;
+    private String mConfiguredVirtualIface;
     private EthernetCallback mEthernetCallback;
     private TetheredInterfaceCallbackShim mBluetoothCallback;
     private SettingsObserver mSettingsObserver;
@@ -719,6 +721,9 @@ public class Tethering {
             case TETHERING_ETHERNET:
                 result = setEthernetTethering(enable);
                 break;
+            case TETHERING_VIRTUAL:
+                result = setVirtualMachineTethering(enable);
+                break;
             default:
                 Log.w(TAG, "Invalid tether type.");
                 result = TETHER_ERROR_UNKNOWN_TYPE;
@@ -972,6 +977,21 @@ public class Tethering {
         }
     }
 
+    private int setVirtualMachineTethering(final boolean enable) {
+        // TODO(340377643): Use bridge ifname when it's introduced, not fixed TAP ifname.
+        if (enable) {
+            mConfiguredVirtualIface = "avf_tap_fixed";
+            enableIpServing(
+                    TETHERING_VIRTUAL,
+                    mConfiguredVirtualIface,
+                    getRequestedState(TETHERING_VIRTUAL));
+        } else if (mConfiguredVirtualIface != null) {
+            ensureIpServerStopped(mConfiguredVirtualIface);
+            mConfiguredVirtualIface = null;
+        }
+        return TETHER_ERROR_NO_ERROR;
+    }
+
     void tether(String iface, int requestedState, final IIntResultListener listener) {
         mHandler.post(() -> {
             try {
diff --git a/common/flags.aconfig b/common/flags.aconfig
index bc4168b6cb..b320b61ee7 100644
--- a/common/flags.aconfig
+++ b/common/flags.aconfig
@@ -115,3 +115,11 @@ flag {
   description: "Flag for NET_CAPABILITY_NOT_BANDWIDTH_CONSTRAINED API"
   bug: "343823469"
 }
+
+flag {
+  name: "tethering_request_virtual"
+  is_exported: true
+  namespace: "android_core_networking"
+  description: "Flag for introducing TETHERING_VIRTUAL type"
+  bug: "340376953"
+}