attributereply.java

Introduction to Sybase IQ.pdf

/* Copyright (c) 2005-2008 Jan S. Rellermeyer
 * Information and Communication Systems Research Group (IKS),
 * Department of Computer Science, ETH Zurich.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *    - Redistributions of source code must retain the above copyright notice,
 *      this list of conditions and the following disclaimer.
 *    - Redistributions in binary form must reproduce the above copyright
 *      notice, this list of conditions and the following disclaimer in the
 *      documentation and/or other materials provided with the distribution.
 *    - Neither the name of ETH Zurich nor the names of its contributors may be
 *      used to endorse or promote products derived from this software without
 *      specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */
package ch.ethz.iks.slp.impl;

import java.io.ByteArrayOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.util.List;

import ch.ethz.iks.slp.ServiceLocationException;

/**
 * a AttributeReply Message is sent as reaction to a AttributeRequest message.
 * 
 * @author Jan S. Rellermeyer, Systems Group, ETH Z黵ich
 * @since 0.1
 */
class AttributeReply extends ReplyMessage {
	/**
	 * a List of attributes that have been retrieved.
	 */
	List attributes;

	/**
	 * an array of AuthenticationBlocks. Used to verify that the reply has not
	 * been modified during transport.
	 */
	AuthenticationBlock[] authBlocks;

	/**
	 * create a new AttributeReply from a list of attributes.
	 * 
	 * @param attList
	 *            a list of attributes in
	 * 
	 * <verbatim> (key=value) </verbatim>
	 * 
	 * format.
	 */
	AttributeReply(final AttributeRequest req, final List attList) {
		funcID = ATTRRPLY;
		errorCode = 0;
		attributes = attList;
		locale = req.locale;
		xid = req.xid;
		address = req.address;
		port = req.port;
		authBlocks = new AuthenticationBlock[0];
	}

	/**
	 * create a new AttributeReply from a DataInput streaming the bytes of an
	 * AttributeReply message body.
	 * 
	 * @param input
	 *            stream of bytes forming the message body.
	 * @throws ServiceLocationException
	 *             in case that the IO caused an exception.
	 */
	AttributeReply(final DataInputStream input) throws IOException,
			ServiceLocationException {
		errorCode = input.readShort();
		attributes = stringToList(input.readUTF(), ",");
		authBlocks = AuthenticationBlock.parse(input);

		if (SLPCore.CONFIG.getSecurityEnabled()) {
			if (!verify()) {
				throw new ServiceLocationException(
						ServiceLocationException.AUTHENTICATION_FAILED,
						"Authentication failed for " + toString());
			}
		}
	}

	/**
	 * get the bytes of the message body in the following RFC 2608 compliant
	 * format:
	 * <p>
	 * 
	 * <pre>
	 *    0                   1                   2                   3
	 *    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
	 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 *   |       Service Location header (function = AttrRply = 7)       |
	 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 *   |         Error Code            |      length of &lt;attr-list&gt;    |
	 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 *   |                         &lt;attr-list&gt;                           \
	 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 *   |# of AttrAuths |  Attribute Authentication Block (if present)  \
	 *   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
	 * </pre>.
	 * </p>
	 * 
	 * @return array of bytes.
	 * @throws ServiceLocationException
	 *             if an IO Exception occurs.
	 * @throws IOException 
	 */
	void writeTo(final DataOutputStream out) throws IOException {
		super.writeHeader(out, getSize());
			out.writeShort(errorCode);
			out.writeUTF(listToString(attributes, ","));
			out.write(authBlocks.length);
			for (int i = 0; i < authBlocks.length; i++) {
				authBlocks[i].write(out);
			}
	}
	
	/**
	 * get the length of the message.
	 * 
	 * @return the length of the message.
	 * @see ch.ethz.iks.slp.impl.SLPMessage#getSize()
	 */
	int getSize() {
		int len = getHeaderSize() + 4 + listToString(attributes, ",").length() + 1;
		for (int i=0; i<authBlocks.length; i++) {
			len += authBlocks[i].getLength();
		}
		return len;
	}

	/**
	 * get the result.
	 * 
	 * @see ch.ethz.iks.slp.impl.ReplyMessage#getResult()
	 * @return the <code>List</code> of results.
	 */
	List getResult() {
		return attributes;
	}

	/**
	 * get a string representation of the AttributeReply message.
	 * 
	 * @return a String displaying the properties of this message instance.
	 */
	public String toString() {
		StringBuffer buffer = new StringBuffer();
		buffer.append(super.toString());
		buffer.append(", errorCode " + errorCode);
		buffer.append(", attrCount " + attributes.size());
		buffer.append(", attributes " + attributes);
		return buffer.toString();
	}

	/**
	 * sign this AttributeReply.
	 * 
	 * @param spiStr
	 *            a String of SPIs.
	 * @throws ServiceLocationException
	 *             in case of IO errors.
	 */
	void sign(final String spiStr) throws ServiceLocationException {
		List spiList = stringToList(spiStr, ",");
		authBlocks = new AuthenticationBlock[spiList.size()];
		for (int k = 0; k < spiList.size(); k++) {
			int timestamp = SLPUtils.getTimestamp();

			String spi = (String) spiList.get(k);
			byte[] data = getAuthData(spi, timestamp);
			authBlocks[k] = new AuthenticationBlock(
					AuthenticationBlock.BSD_DSA, spi, timestamp, data, null);
		}
	}

	/**
	 * verify this AttributeReply.
	 * 
	 * @return true if verification suceeds.
	 * @throws ServiceLocationException
	 *             in case of IO errors.
	 */
	boolean verify() throws ServiceLocationException {
		for (int i = 0; i < authBlocks.length; i++) {
			if (authBlocks[i].verify(getAuthData(authBlocks[i].getSPI(),
					authBlocks[i].getTimestamp()))) {
				return true;
			}
		}
		return false;
	}

	/**
	 * get the authentication data.
	 * 
	 * @param spiStr
	 *            the SPI.
	 * @param timestamp
	 *            the timestamp.
	 * @return the auth data.
	 * @throws ServiceLocationException
	 *             in case of IO errors.
	 */
	private byte[] getAuthData(final String spiStr, final int timestamp)
			throws ServiceLocationException {
		try {
			ByteArrayOutputStream bos = new ByteArrayOutputStream();
			DataOutputStream dos = new DataOutputStream(bos);
			dos.writeUTF(spiStr);
			dos.writeUTF(listToString(attributes, ","));
			dos.writeInt(timestamp);
			return bos.toByteArray();
		} catch (IOException ioe) {
			throw new ServiceLocationException(
					ServiceLocationException.INTERNAL_SYSTEM_ERROR, ioe
							.getMessage());
		}
	}
}