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/*
* Copyright (C) 2022 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.content.Context;
import android.net.INetd;
import android.os.Handler;
import android.os.IBinder;
import android.os.RemoteException;
import android.os.ServiceSpecificException;
import android.system.ErrnoException;
import android.util.Log;
import com.android.internal.annotations.VisibleForTesting;
import com.android.net.module.util.BaseNetdUnsolicitedEventListener;
import com.android.net.module.util.BpfMap;
import com.android.net.module.util.IBpfMap;
import com.android.net.module.util.InterfaceParams;
import com.android.net.module.util.Struct.U32;
/**
* Monitor interface added (without removed) and right interface name and its index to bpf map.
*/
public class BpfInterfaceMapUpdater {
private static final String TAG = BpfInterfaceMapUpdater.class.getSimpleName();
// This is current path but may be changed soon.
private static final String IFACE_INDEX_NAME_MAP_PATH =
"/sys/fs/bpf/netd_shared/map_netd_iface_index_name_map";
private final IBpfMap<U32, InterfaceMapValue> mBpfMap;
private final INetd mNetd;
private final Handler mHandler;
private final Dependencies mDeps;
public BpfInterfaceMapUpdater(Context ctx, Handler handler) {
this(ctx, handler, new Dependencies());
}
@VisibleForTesting
public BpfInterfaceMapUpdater(Context ctx, Handler handler, Dependencies deps) {
mDeps = deps;
mBpfMap = deps.getInterfaceMap();
mNetd = deps.getINetd(ctx);
mHandler = handler;
}
/**
* Dependencies of BpfInerfaceMapUpdater, for injection in tests.
*/
@VisibleForTesting
public static class Dependencies {
/** Create BpfMap for updating interface and index mapping. */
public IBpfMap<U32, InterfaceMapValue> getInterfaceMap() {
try {
return new BpfMap<>(IFACE_INDEX_NAME_MAP_PATH, BpfMap.BPF_F_RDWR,
U32.class, InterfaceMapValue.class);
} catch (ErrnoException e) {
Log.e(TAG, "Cannot create interface map: " + e);
return null;
}
}
/** Get InterfaceParams for giving interface name. */
public InterfaceParams getInterfaceParams(String ifaceName) {
return InterfaceParams.getByName(ifaceName);
}
/** Get INetd binder object. */
public INetd getINetd(Context ctx) {
return INetd.Stub.asInterface((IBinder) ctx.getSystemService(Context.NETD_SERVICE));
}
}
/**
* Start listening interface update event.
* Query current interface names before listening.
*/
public void start() {
mHandler.post(() -> {
if (mBpfMap == null) {
Log.wtf(TAG, "Fail to start: Null bpf map");
return;
}
try {
// TODO: use a NetlinkMonitor and listen for RTM_NEWLINK messages instead.
mNetd.registerUnsolicitedEventListener(new InterfaceChangeObserver());
} catch (RemoteException e) {
Log.wtf(TAG, "Unable to register netd UnsolicitedEventListener, " + e);
}
final String[] ifaces;
try {
// TODO: use a netlink dump to get the current interface list.
ifaces = mNetd.interfaceGetList();
} catch (RemoteException | ServiceSpecificException e) {
Log.wtf(TAG, "Unable to query interface names by netd, " + e);
return;
}
for (String ifaceName : ifaces) {
addInterface(ifaceName);
}
});
}
private void addInterface(String ifaceName) {
final InterfaceParams iface = mDeps.getInterfaceParams(ifaceName);
if (iface == null) {
Log.e(TAG, "Unable to get InterfaceParams for " + ifaceName);
return;
}
try {
mBpfMap.updateEntry(new U32(iface.index), new InterfaceMapValue(ifaceName));
} catch (ErrnoException e) {
Log.e(TAG, "Unable to update entry for " + ifaceName + ", " + e);
}
}
private class InterfaceChangeObserver extends BaseNetdUnsolicitedEventListener {
@Override
public void onInterfaceAdded(String ifName) {
mHandler.post(() -> addInterface(ifName));
}
}
}
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