package android.net;
import static android.net.ConnectivityManager.PacketKeepalive.*;
import android.net.util.IpUtils;
import android.os.Parcel;
import android.os.Parcelable;
import android.system.OsConstants;
import android.util.Log;
import java.net.Inet4Address;
import java.net.InetAddress;
import java.nio.ByteBuffer;
import java.nio.ByteOrder;
public class KeepalivePacketData implements Parcelable {
private static final String TAG = "KeepalivePacketData";
public final InetAddress srcAddress;
public final InetAddress dstAddress;
public final int srcPort;
public final int dstPort;
private final byte[] mPacket;
private static final int IPV4_HEADER_LENGTH = 20;
private static final int UDP_HEADER_LENGTH = 8;
protected KeepalivePacketData(InetAddress srcAddress, int srcPort,
InetAddress dstAddress, int dstPort, byte[] data) throws InvalidPacketException {
this.srcAddress = srcAddress;
this.dstAddress = dstAddress;
this.srcPort = srcPort;
this.dstPort = dstPort;
this.mPacket = data;
if (srcAddress == null || dstAddress == null || !srcAddress.getClass().getName()
.equals(dstAddress.getClass().getName())) {
Log.e(TAG, "Invalid or mismatched InetAddresses in KeepalivePacketData");
throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
}
if (!IpUtils.isValidUdpOrTcpPort(srcPort) || !IpUtils.isValidUdpOrTcpPort(dstPort)) {
Log.e(TAG, "Invalid ports in KeepalivePacketData");
throw new InvalidPacketException(ERROR_INVALID_PORT);
}
}
public static class InvalidPacketException extends Exception {
public final int error;
public InvalidPacketException(int error) {
this.error = error;
}
}
public byte[] getPacket() {
return mPacket.clone();
}
public static KeepalivePacketData nattKeepalivePacket(
InetAddress srcAddress, int srcPort, InetAddress dstAddress, int dstPort)
throws InvalidPacketException {
if (!(srcAddress instanceof Inet4Address) || !(dstAddress instanceof Inet4Address)) {
throw new InvalidPacketException(ERROR_INVALID_IP_ADDRESS);
}
if (dstPort != NATT_PORT) {
throw new InvalidPacketException(ERROR_INVALID_PORT);
}
int length = IPV4_HEADER_LENGTH + UDP_HEADER_LENGTH + 1;
ByteBuffer buf = ByteBuffer.allocate(length);
buf.order(ByteOrder.BIG_ENDIAN);
buf.putShort((short) 0x4500);
buf.putShort((short) length);
buf.putInt(0);
buf.put((byte) 64);
buf.put((byte) OsConstants.IPPROTO_UDP);
int ipChecksumOffset = buf.position();
buf.putShort((short) 0);
buf.put(srcAddress.getAddress());
buf.put(dstAddress.getAddress());
buf.putShort((short) srcPort);
buf.putShort((short) dstPort);
buf.putShort((short) (length - 20));
int udpChecksumOffset = buf.position();
buf.putShort((short) 0);
buf.put((byte) 0xff);
buf.putShort(ipChecksumOffset, IpUtils.ipChecksum(buf, 0));
buf.putShort(udpChecksumOffset, IpUtils.udpChecksum(buf, 0, IPV4_HEADER_LENGTH));
return new KeepalivePacketData(srcAddress, srcPort, dstAddress, dstPort, buf.array());
}
public int describeContents() {
return 0;
}
public void writeToParcel(Parcel out, int flags) {
out.writeString(srcAddress.getHostAddress());
out.writeString(dstAddress.getHostAddress());
out.writeInt(srcPort);
out.writeInt(dstPort);
out.writeByteArray(mPacket);
}
private KeepalivePacketData(Parcel in) {
srcAddress = NetworkUtils.numericToInetAddress(in.readString());
dstAddress = NetworkUtils.numericToInetAddress(in.readString());
srcPort = in.readInt();
dstPort = in.readInt();
mPacket = in.createByteArray();
}
public static final Parcelable.Creator<KeepalivePacketData> CREATOR =
new Parcelable.Creator<KeepalivePacketData>() {
public KeepalivePacketData createFromParcel(Parcel in) {
return new KeepalivePacketData(in);
}
public KeepalivePacketData[] newArray(int size) {
return new KeepalivePacketData[size];
}
};
}