/****************************************************************************
* Copyright (c) 2005, 2010 Jan S. Rellermeyer, Systems Group,
* Department of Computer Science, ETH Zurich and others.
* All rights reserved. This program and the accompanying materials
* are made available under the terms of the Eclipse Public License v1.0
* which accompanies this distribution, and is available at
* http://www.eclipse.org/legal/epl-v10.html
*
* Contributors:
* Jan S. Rellermeyer - initial API and implementation
* Markus Alexander Kuppe - enhancements and bug fixes
*
*****************************************************************************/
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�rich
* @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 = attributeStringToListLiberal(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 <attr-list> |
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* | <attr-list> \
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* |# of AttrAuths | Attribute Authentication Block (if present) \
* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
* </pre>.
* </p>
*
* @return array of bytes.
* @throws ServiceLocationException
* if an IO Exception occurs.
* @throws IOException
*/
protected void writeTo(final DataOutputStream out) throws IOException {
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()
*/
protected 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());
}
}
}