Add L2capNetwork class
The L2capNetwork class keeps track of the IpClient (configured in IPv6
link-local only mode), NetworkAgent, and L2capPacketForwarder.
Test: mm
Change-Id: Icfba2964dec7e8260973591395a391d30bbae6c2
diff --git a/service/src/com/android/server/net/L2capNetwork.java b/service/src/com/android/server/net/L2capNetwork.java
new file mode 100644
index 0000000..b9d5f13
--- /dev/null
+++ b/service/src/com/android/server/net/L2capNetwork.java
@@ -0,0 +1,141 @@
+/*
+ * Copyright (C) 2025 The Android Open Source Project
+ *
+ * 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.server.net;
+
+import android.annotation.Nullable;
+import android.bluetooth.BluetoothSocket;
+import android.content.Context;
+import android.net.LinkProperties;
+import android.net.NetworkAgent;
+import android.net.NetworkAgentConfig;
+import android.net.NetworkCapabilities;
+import android.net.NetworkProvider;
+import android.net.NetworkScore;
+import android.net.ip.IIpClient;
+import android.net.ip.IpClientCallbacks;
+import android.net.ip.IpClientManager;
+import android.net.ip.IpClientUtil;
+import android.net.shared.ProvisioningConfiguration;
+import android.os.ConditionVariable;
+import android.os.Handler;
+import android.os.ParcelFileDescriptor;
+import android.util.Log;
+
+public class L2capNetwork {
+ private static final NetworkScore NETWORK_SCORE = new NetworkScore.Builder().build();
+ private final String mLogTag;
+ private final Handler mHandler;
+ private final String mIfname;
+ private final L2capPacketForwarder mForwarder;
+ private final NetworkCapabilities mNetworkCapabilities;
+ private final L2capIpClient mIpClient;
+ private final NetworkAgent mNetworkAgent;
+
+ /** IpClient wrapper to handle IPv6 link-local provisioning for L2CAP tun.
+ *
+ * Note that the IpClient does not need to be stopped.
+ */
+ private static class L2capIpClient extends IpClientCallbacks {
+ private final String mLogTag;
+ private final ConditionVariable mOnIpClientCreatedCv = new ConditionVariable(false);
+ private final ConditionVariable mOnProvisioningSuccessCv = new ConditionVariable(false);
+ @Nullable
+ private IpClientManager mIpClient;
+ @Nullable
+ private LinkProperties mLinkProperties;
+
+ L2capIpClient(String logTag, Context context, String ifname) {
+ mLogTag = logTag;
+ IpClientUtil.makeIpClient(context, ifname, this);
+ }
+
+ @Override
+ public void onIpClientCreated(IIpClient ipClient) {
+ mIpClient = new IpClientManager(ipClient, mLogTag);
+ mOnIpClientCreatedCv.open();
+ }
+
+ @Override
+ public void onProvisioningSuccess(LinkProperties lp) {
+ Log.d(mLogTag, "Successfully provisionined l2cap tun: " + lp);
+ mLinkProperties = lp;
+ mOnProvisioningSuccessCv.open();
+ }
+
+ public LinkProperties start() {
+ mOnIpClientCreatedCv.block();
+ // mIpClient guaranteed non-null.
+ final ProvisioningConfiguration config = new ProvisioningConfiguration.Builder()
+ .withoutIPv4()
+ .withIpv6LinkLocalOnly()
+ .withRandomMacAddress() // addr_gen_mode EUI64 -> random on tun.
+ .build();
+ mIpClient.startProvisioning(config);
+ // "Provisioning" is guaranteed to succeed as link-local only mode does not actually
+ // require any provisioning.
+ mOnProvisioningSuccessCv.block();
+ return mLinkProperties;
+ }
+ }
+
+ public interface ICallback {
+ /** Called when an error is encountered */
+ void onError(L2capNetwork network);
+ /** Called when CS triggers NetworkAgent#onNetworkUnwanted */
+ void onNetworkUnwanted(L2capNetwork network);
+ }
+
+ public L2capNetwork(Handler handler, Context context, NetworkProvider provider, String ifname,
+ BluetoothSocket socket, ParcelFileDescriptor tunFd,
+ NetworkCapabilities networkCapabilities, ICallback cb) {
+ // TODO: add a check that this constructor is invoked on the handler thread.
+ mLogTag = String.format("L2capNetwork[%s]", ifname);
+ mHandler = handler;
+ mIfname = ifname;
+ mForwarder = new L2capPacketForwarder(handler, tunFd, socket, () -> {
+ // TODO: add a check that this callback is invoked on the handler thread.
+ cb.onError(L2capNetwork.this);
+ });
+ mNetworkCapabilities = networkCapabilities;
+ mIpClient = new L2capIpClient(mLogTag, context, ifname);
+ final LinkProperties linkProperties = mIpClient.start();
+
+ final NetworkAgentConfig config = new NetworkAgentConfig.Builder().build();
+ mNetworkAgent = new NetworkAgent(context, mHandler.getLooper(), mLogTag,
+ networkCapabilities, linkProperties, NETWORK_SCORE, config, provider) {
+ @Override
+ public void onNetworkUnwanted() {
+ Log.i(mLogTag, mIfname + ": Network is unwanted");
+ // TODO: add a check that this callback is invoked on the handler thread.
+ cb.onNetworkUnwanted(L2capNetwork.this);
+ }
+ };
+ mNetworkAgent.register();
+ mNetworkAgent.markConnected();
+ }
+
+ /** Get the NetworkCapabilities used for this Network */
+ public NetworkCapabilities getNetworkCapabilities() {
+ return mNetworkCapabilities;
+ }
+
+ /** Tear down the network and associated resources */
+ public void tearDown() {
+ mNetworkAgent.unregister();
+ mForwarder.tearDown();
+ }
+}