/*
* Copyright (c) 2012 Alexander Diener,
*
* This program is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
* FOR A PARTICULAR PURPOSE. See the GNU General Public License for more
* details.
*
* You should have received a copy of the GNU General Public License along with
* this program. If not, see <http://www.gnu.org/licenses/>.
*/
package de.fhkn.in.uce.stun.attribute.rfc3489;
import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.net.Inet4Address;
import java.net.Inet6Address;
import java.net.InetAddress;
import java.net.InetSocketAddress;
import de.fhkn.in.uce.stun.attribute.Attribute;
import de.fhkn.in.uce.stun.attribute.AttributeHeader;
import de.fhkn.in.uce.stun.attribute.AttributeType;
import de.fhkn.in.uce.stun.util.MessageFormatException;
/**
* The SOURCE-ADDRESS attribute indicates the source IP address and port that
* the server is sending the response from. Its syntax is identical to that of
* MAPPED- ADDRESS.
*
* @author Alexander Diener (aldiener@htwg-konstanz.de)
*
*/
public final class SourceAddress implements Attribute {
private static final int IPV4_FAMILY = 0x01;
private static final int IPV6_FAMILY = 0x02;
private static final int IPV4_MESSAGE_LENGTH = 8;
private static final int IPV6_MESSAGE_LENGTH = 20;
private final InetSocketAddress endpoint;
private final int length;
private final int ipFamily;
/**
* Creates a {@link SourceAddress} attribute for an endpoint.
*
* @param endpoint
* the endpoint for the attribute
*/
public SourceAddress(final InetSocketAddress endpoint) {
this.length = this.determineLengthOfAttribute(endpoint);
this.endpoint = endpoint;
this.ipFamily = this.determineIpFamily(endpoint);
}
private int determineLengthOfAttribute(final InetSocketAddress endpoint) {
int result = 0;
if (endpoint.getAddress() instanceof Inet4Address) {
result = IPV4_MESSAGE_LENGTH;
} else if (endpoint.getAddress() instanceof Inet6Address) {
result = IPV6_MESSAGE_LENGTH;
} else {
throw new IllegalArgumentException("Unknown address familiy " + endpoint.getAddress().getClass()); //$NON-NLS-1$
}
return result;
}
private int determineIpFamily(final InetSocketAddress endpoint) {
int result;
if (endpoint.getAddress() instanceof Inet4Address) {
result = IPV4_FAMILY;
} else if (endpoint.getAddress() instanceof Inet6Address) {
result = IPV6_FAMILY;
} else {
throw new IllegalArgumentException("Unknown address familiy " + endpoint.getAddress().getClass()); //$NON-NLS-1$
}
return result;
}
/**
* Returns the endpoint.
*
* @return the endpoint
*/
public InetSocketAddress getEndpoint() {
return this.endpoint;
}
@Override
public AttributeType getType() {
return Rfc3489AttributeType.SOURCE_ADDRESS;
}
@Override
public int getLength() {
return this.length;
}
@Override
public void writeTo(final OutputStream out) throws IOException {
final ByteArrayOutputStream bout = new ByteArrayOutputStream();
final DataOutputStream dout = new DataOutputStream(bout);
// leading zeros
dout.writeByte(0x00);
dout.writeByte(this.ipFamily);
dout.writeShort(this.endpoint.getPort());
dout.write(this.endpoint.getAddress().getAddress());
out.write(bout.toByteArray());
out.flush();
}
/**
* Creates a {@link SourceAddress} from the given encoded attribute and
* header.
*
* @param encoded
* the encoded {@link SourceAddress} attribute
* @param header
* the attribute header
* @return the {@link SourceAddress} of the given encoding
* @throws IOException
* if an I/O exception occurs
* @throws MessageFormatException
* if the encoded {@link SourceAddress} is malformed
*/
public static SourceAddress fromBytes(final byte[] encoded, final AttributeHeader header) throws IOException,
MessageFormatException {
final ByteArrayInputStream bin = new ByteArrayInputStream(encoded);
final DataInputStream din = new DataInputStream(bin);
final int leadingZeroBits = din.readUnsignedByte();
checkLeadingZeros(leadingZeroBits);
final int ipFamilyBits = din.readUnsignedByte();
final byte[] ipAsBytes = getByteArrayForIp(ipFamilyBits);
final int port = din.readUnsignedShort();
din.readFully(ipAsBytes);
final InetAddress address = InetAddress.getByAddress(ipAsBytes);
return new SourceAddress(new InetSocketAddress(address, port));
}
private static void checkLeadingZeros(final int leadingZeroBits) throws MessageFormatException {
if (leadingZeroBits != 0) {
throw new MessageFormatException("Wrong message format, the leading zeros were " + leadingZeroBits); //$NON-NLS-1$
}
}
private static byte[] getByteArrayForIp(final int ipFamilyBits) throws MessageFormatException {
byte[] bytesForIp;
if (ipFamilyBits == IPV4_FAMILY) {
bytesForIp = new byte[4];
} else if (ipFamilyBits == IPV6_FAMILY) {
bytesForIp = new byte[16];
} else {
throw new MessageFormatException("Unknown address family " + ipFamilyBits); //$NON-NLS-1$
}
return bytesForIp;
}
}