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/*
* Copyright (C) 2015 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 android.net.netlink;
import android.system.ErrnoException;
import android.system.NetlinkSocketAddress;
import android.system.Os;
import android.system.OsConstants;
import android.system.StructTimeval;
import android.util.Log;
import libcore.io.IoUtils;
import libcore.io.Libcore;
import java.io.Closeable;
import java.io.FileDescriptor;
import java.io.InterruptedIOException;
import java.net.SocketAddress;
import java.net.SocketException;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
/**
* NetlinkSocket
*
* A small wrapper class to assist with AF_NETLINK socket operations.
*
* @hide
*/
public class NetlinkSocket implements Closeable {
private static final String TAG = "NetlinkSocket";
private static final int SOCKET_RECV_BUFSIZE = 64 * 1024;
private static final int DEFAULT_RECV_BUFSIZE = 8 * 1024;
final private FileDescriptor mDescriptor;
private NetlinkSocketAddress mAddr;
private long mLastRecvTimeoutMs;
private long mLastSendTimeoutMs;
public NetlinkSocket(int nlProto) throws ErrnoException {
mDescriptor = Os.socket(
OsConstants.AF_NETLINK, OsConstants.SOCK_DGRAM, nlProto);
Libcore.os.setsockoptInt(
mDescriptor, OsConstants.SOL_SOCKET,
OsConstants.SO_RCVBUF, SOCKET_RECV_BUFSIZE);
}
public NetlinkSocketAddress getLocalAddress() throws ErrnoException {
return (NetlinkSocketAddress) Os.getsockname(mDescriptor);
}
public void bind(NetlinkSocketAddress localAddr) throws ErrnoException, SocketException {
Os.bind(mDescriptor, (SocketAddress)localAddr);
}
public void connectTo(NetlinkSocketAddress peerAddr)
throws ErrnoException, SocketException {
Os.connect(mDescriptor, (SocketAddress) peerAddr);
}
public void connectToKernel() throws ErrnoException, SocketException {
connectTo(new NetlinkSocketAddress(0, 0));
}
/**
* Wait indefinitely (or until underlying socket error) for a
* netlink message of at most DEFAULT_RECV_BUFSIZE size.
*/
public ByteBuffer recvMessage()
throws ErrnoException, InterruptedIOException {
return recvMessage(DEFAULT_RECV_BUFSIZE, 0);
}
/**
* Wait up to |timeoutMs| (or until underlying socket error) for a
* netlink message of at most DEFAULT_RECV_BUFSIZE size.
*/
public ByteBuffer recvMessage(long timeoutMs) throws ErrnoException, InterruptedIOException {
return recvMessage(DEFAULT_RECV_BUFSIZE, timeoutMs);
}
private void checkTimeout(long timeoutMs) {
if (timeoutMs < 0) {
throw new IllegalArgumentException("Negative timeouts not permitted");
}
}
/**
* Wait up to |timeoutMs| (or until underlying socket error) for a
* netlink message of at most |bufsize| size.
*
* Multi-threaded calls with different timeouts will cause unexpected results.
*/
public ByteBuffer recvMessage(int bufsize, long timeoutMs)
throws ErrnoException, IllegalArgumentException, InterruptedIOException {
checkTimeout(timeoutMs);
synchronized (mDescriptor) {
if (mLastRecvTimeoutMs != timeoutMs) {
Os.setsockoptTimeval(mDescriptor,
OsConstants.SOL_SOCKET, OsConstants.SO_RCVTIMEO,
StructTimeval.fromMillis(timeoutMs));
mLastRecvTimeoutMs = timeoutMs;
}
}
ByteBuffer byteBuffer = ByteBuffer.allocate(bufsize);
int length = Os.read(mDescriptor, byteBuffer);
if (length == bufsize) {
Log.w(TAG, "maximum read");
}
byteBuffer.position(0);
byteBuffer.limit(length);
byteBuffer.order(ByteOrder.nativeOrder());
return byteBuffer;
}
/**
* Send a message to a peer to which this socket has previously connected.
*
* This blocks until completion or an error occurs.
*/
public boolean sendMessage(byte[] bytes, int offset, int count)
throws ErrnoException, InterruptedIOException {
return sendMessage(bytes, offset, count, 0);
}
/**
* Send a message to a peer to which this socket has previously connected,
* waiting at most |timeoutMs| milliseconds for the send to complete.
*
* Multi-threaded calls with different timeouts will cause unexpected results.
*/
public boolean sendMessage(byte[] bytes, int offset, int count, long timeoutMs)
throws ErrnoException, IllegalArgumentException, InterruptedIOException {
checkTimeout(timeoutMs);
synchronized (mDescriptor) {
if (mLastSendTimeoutMs != timeoutMs) {
Os.setsockoptTimeval(mDescriptor,
OsConstants.SOL_SOCKET, OsConstants.SO_SNDTIMEO,
StructTimeval.fromMillis(timeoutMs));
mLastSendTimeoutMs = timeoutMs;
}
}
return (count == Os.write(mDescriptor, bytes, offset, count));
}
@Override
public void close() {
IoUtils.closeQuietly(mDescriptor);
}
}
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