B2buaHelperImpl.java

/*
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 */
package org.mobicents.servlet.sip.message;

import gov.nist.javax.sip.header.ims.PathHeader;
import gov.nist.javax.sip.message.SIPMessage;

import java.io.Serializable;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.Map.Entry;
import java.util.concurrent.ConcurrentHashMap;

import javax.servlet.ServletException;
import javax.servlet.sip.B2buaHelper;
import javax.servlet.sip.SipServletMessage;
import javax.servlet.sip.SipServletRequest;
import javax.servlet.sip.SipServletResponse;
import javax.servlet.sip.SipSession;
import javax.servlet.sip.TooManyHopsException;
import javax.servlet.sip.UAMode;
import javax.servlet.sip.SipSession.State;
import javax.servlet.sip.ar.SipApplicationRoutingDirective;
import javax.sip.ClientTransaction;
import javax.sip.ServerTransaction;
import javax.sip.Transaction;
import javax.sip.header.CSeqHeader;
import javax.sip.header.CallIdHeader;
import javax.sip.header.ContactHeader;
import javax.sip.header.ContentDispositionHeader;
import javax.sip.header.ContentLengthHeader;
import javax.sip.header.ContentTypeHeader;
import javax.sip.header.FromHeader;
import javax.sip.header.Header;
import javax.sip.header.MaxForwardsHeader;
import javax.sip.header.RecordRouteHeader;
import javax.sip.header.RouteHeader;
import javax.sip.header.ToHeader;
import javax.sip.header.ViaHeader;
import javax.sip.message.Request;

import org.apache.log4j.Logger;
import org.mobicents.servlet.sip.JainSipUtils;
import org.mobicents.servlet.sip.SipFactories;
import org.mobicents.servlet.sip.core.ApplicationRoutingHeaderComposer;
import org.mobicents.servlet.sip.core.ExtendedListeningPoint;
import org.mobicents.servlet.sip.core.RoutingState;
import org.mobicents.servlet.sip.core.session.MobicentsSipApplicationSession;
import org.mobicents.servlet.sip.core.session.MobicentsSipSession;
import org.mobicents.servlet.sip.core.session.SessionManagerUtil;
import org.mobicents.servlet.sip.core.session.SipManager;
import org.mobicents.servlet.sip.core.session.SipSessionKey;

/**
 * Implementation of the B2BUA helper class.
 * 
 * 
 * @author mranga
 * @author Jean Deruelle
 */

public class B2buaHelperImpl implements B2buaHelper, Serializable {
	private static final long serialVersionUID = 1L;

	private static transient Logger logger = Logger.getLogger(B2buaHelperImpl.class);
	
	protected transient static final HashSet<String> singletonHeadersNames = new HashSet<String>();
	static {
		singletonHeadersNames.add(FromHeader.NAME);
		singletonHeadersNames.add(ToHeader.NAME);
		singletonHeadersNames.add(CSeqHeader.NAME);
		singletonHeadersNames.add(CallIdHeader.NAME);
		singletonHeadersNames.add(MaxForwardsHeader.NAME);
		singletonHeadersNames.add(ContentLengthHeader.NAME);		
		singletonHeadersNames.add(ContentDispositionHeader.NAME);
		singletonHeadersNames.add(ContentTypeHeader.NAME);
		//TODO are there any other singleton headers ?
	}	
	
	protected transient static final HashSet<String> b2buaSystemHeaders = new HashSet<String>();
	static {
		b2buaSystemHeaders.add(CallIdHeader.NAME);
		b2buaSystemHeaders.add(CSeqHeader.NAME);
		b2buaSystemHeaders.add(ViaHeader.NAME);
		b2buaSystemHeaders.add(RouteHeader.NAME);
		b2buaSystemHeaders.add(RecordRouteHeader.NAME);
		b2buaSystemHeaders.add(PathHeader.NAME);
	}
	
	//Map to handle linked sessions
	private Map<SipSessionKey, SipSessionKey> sessionMap = null;	

	//Map to handle responses to original request and cancel on original request
	private transient Map<SipSessionKey, SipServletRequest> originalRequestMap = null;

	private transient SipFactoryImpl sipFactoryImpl;
	
	private transient SipManager sipManager;

	public B2buaHelperImpl() {
		sessionMap = new ConcurrentHashMap<SipSessionKey, SipSessionKey>();
		originalRequestMap = new ConcurrentHashMap<SipSessionKey, SipServletRequest>();
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#createRequest(javax.servlet.sip.SipServletRequest, boolean, java.util.Map)
	 */
	public SipServletRequest createRequest(SipServletRequest origRequest,
			boolean linked, Map<String, List<String>> headerMap) throws TooManyHopsException {
		
		if(origRequest == null) {
			throw new NullPointerException("original request cannot be null");
		}
		
		if(origRequest.getMaxForwards() == 0) {
			throw new TooManyHopsException();
		}
		
		try {
			final SipServletRequestImpl origRequestImpl = (SipServletRequestImpl) origRequest;
			Request newRequest = (Request) origRequestImpl.message.clone();
			((SIPMessage)newRequest).setApplicationData(null);
			//content should be copied too, so commented out
//		 	newRequest.removeContent();				
			//removing the via header from original request
			newRequest.removeHeader(ViaHeader.NAME);	
						
			// Remove the route header ( will point to us ).
			// commented as per issue 649
//			newRequest.removeHeader(RouteHeader.NAME);
//			String tag = Integer.toString((int) (Math.random()*1000));
//			((FromHeader) newRequest.getHeader(FromHeader.NAME)).setParameter("tag", tag);
			
			// Remove the record route headers. This is a new call leg.
			newRequest.removeHeader(RecordRouteHeader.NAME);
			
			//For non-REGISTER requests, the Contact header field is not copied 
			//but is populated by the container as usualB2buaHelperImpl
			if(!Request.REGISTER.equalsIgnoreCase(origRequest.getMethod())) {
				newRequest.removeHeader(ContactHeader.NAME);
			}
	
			//Creating new call id
			final ExtendedListeningPoint extendedListeningPoint = sipFactoryImpl.getSipNetworkInterfaceManager().getExtendedListeningPoints().next();
			final CallIdHeader callIdHeader = SipFactories.headerFactory.createCallIdHeader(extendedListeningPoint.getSipProvider().getNewCallId().getCallId());
			newRequest.setHeader(callIdHeader);
			
			final List<String> contactHeaderSet = retrieveContactHeaders(headerMap,
					newRequest);	
			final FromHeader newFromHeader = (FromHeader) newRequest.getHeader(FromHeader.NAME);
			newFromHeader.removeParameter("tag");
			((ToHeader) newRequest.getHeader(ToHeader.NAME))
					.removeParameter("tag");
			
			final MobicentsSipSession originalSession = origRequestImpl.getSipSession();
			final MobicentsSipApplicationSession appSession = originalSession
					.getSipApplicationSession();			
			
			newFromHeader.setTag(ApplicationRoutingHeaderComposer.getHash(sipFactoryImpl.getSipApplicationDispatcher(), originalSession.getKey().getApplicationName(), appSession.getKey().getId()));
			
			final SipSessionKey key = SessionManagerUtil.getSipSessionKey(appSession.getKey().getId(), originalSession.getKey().getApplicationName(), newRequest, false);
			final MobicentsSipSession session = appSession.getSipContext().getSipManager().getSipSession(key, true, sipFactoryImpl, appSession);			
			session.setHandler(originalSession.getHandler());
		
			
			final SipServletRequestImpl newSipServletRequest = new SipServletRequestImpl(
					newRequest,
					sipFactoryImpl,					
					session, 
					null, 
					null, 
					JainSipUtils.dialogCreatingMethods.contains(newRequest.getMethod()));			
			//JSR 289 Section 15.1.6
			newSipServletRequest.setRoutingDirective(SipApplicationRoutingDirective.CONTINUE, origRequest);			
			//If Contact header is present in the headerMap 
			//then relevant portions of Contact header is to be used in the request created, 
			//in accordance with section 4.1.3 of the specification.
			for (String contactHeaderValue : contactHeaderSet) {
				newSipServletRequest.addHeaderInternal(ContactHeader.NAME, contactHeaderValue, true);
			}
			
			originalRequestMap.put(originalSession.getKey(), origRequest);
			originalRequestMap.put(session.getKey(), newSipServletRequest);
			
			if (linked) {
				sessionMap.put(originalSession.getKey(), session.getKey());
				sessionMap.put(session.getKey(), originalSession.getKey());
				dumpLinkedSessions();
			}
			session.setB2buaHelper(this);
			originalSession.setB2buaHelper(this);
			
			return newSipServletRequest;
		} catch (ParseException ex) {
			logger.error("Unexpected parse exception ", ex);
			throw new IllegalArgumentException(
					"Illegal arg encountered while creating b2bua", ex);
		} catch (ServletException ex) {
			logger.error("Unexpected exception ", ex);
			throw new IllegalArgumentException(
					"Unexpected problem while creating b2bua", ex);
		}
	}

	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#createRequest(javax.servlet.sip.SipSession, javax.servlet.sip.SipServletRequest, java.util.Map)
	 */
	public SipServletRequest createRequest(SipSession session,
			SipServletRequest origRequest, Map<String, List<String>> headerMap) {
		
		if(origRequest == null) {
			throw new NullPointerException("original request cannot be null");
		}
		
		try {
			final SipServletRequestImpl origRequestImpl = (SipServletRequestImpl) origRequest;
			final MobicentsSipSession originalSession = origRequestImpl.getSipSession();
			final MobicentsSipSession sessionImpl = (MobicentsSipSession) session;

			final SipServletRequestImpl newSubsequentServletRequest = (SipServletRequestImpl) session.createRequest(origRequest.getMethod());
			
			
			//For non-REGISTER requests, the Contact header field is not copied 
			//but is populated by the container as usual
			
			//commented since this is not true in this case since this is a subsequent request
			// this is needed for sending challenge requests
//			if(!Request.REGISTER.equalsIgnoreCase(origRequest.getMethod())) {
//				newSubsequentServletRequest.getMessage().removeHeader(ContactHeader.NAME);
//			}
			//If Contact header is present in the headerMap 
			//then relevant portions of Contact header is to be used in the request created, 
			//in accordance with section 4.1.3 of the specification.
			//They will be added later after the sip servlet request has been created
			final List<String> contactHeaderSet = retrieveContactHeaders(headerMap,
					(Request) newSubsequentServletRequest.getMessage());
						
			//If Contact header is present in the headerMap 
			//then relevant portions of Contact header is to be used in the request created, 
			//in accordance with section 4.1.3 of the specification.
			for (String contactHeaderValue : contactHeaderSet) {
				newSubsequentServletRequest.addHeaderInternal(ContactHeader.NAME, contactHeaderValue, true);
			}
			
			//Fix for Issue 585 by alexandre sova
			if(origRequest.getContent() != null && origRequest.getContentType() != null) {
				newSubsequentServletRequest.setContentLength(origRequest.getContentLength());
				newSubsequentServletRequest.setContent(origRequest.getContent(), origRequest.getContentType());
			}
			
			if(logger.isDebugEnabled()) {
				logger.debug("newSubsequentServletRequest = " + newSubsequentServletRequest);
			}			
			
			originalRequestMap.put(originalSession.getKey(), origRequest);
			originalRequestMap.put(((MobicentsSipSession)session).getKey(), newSubsequentServletRequest);
			
			sessionMap.put(originalSession.getKey(), sessionImpl.getKey());
			sessionMap.put(sessionImpl.getKey(), originalSession.getKey());
			dumpLinkedSessions();

			sessionImpl.setB2buaHelper(this);
			originalSession.setB2buaHelper(this);
			return newSubsequentServletRequest;
		} catch (Exception ex) {
			logger.error("Unexpected exception ", ex);
			throw new IllegalArgumentException(
					"Illegal arg ecnountered while creatigng b2bua", ex);
		}
	}

	/**
	 * @param headerMap
	 * @param newRequest
	 * @return
	 * @throws ParseException
	 */
	private final static List<String> retrieveContactHeaders(
			Map<String, List<String>> headerMap, Request newRequest)
			throws ParseException {
		List<String> contactHeaderList = new ArrayList<String>();
		if(headerMap != null) {
			for (Entry<String, List<String>> entry : headerMap.entrySet()) {
				final String headerName = entry.getKey();
				if(!headerName.equalsIgnoreCase(ContactHeader.NAME)) {
					if(b2buaSystemHeaders.contains(headerName)) {
						throw new IllegalArgumentException(headerName + " in the provided map is a system header");
					}
					for (String value : entry.getValue()) {							
						final Header header = SipFactories.headerFactory.createHeader(
								headerName, value);					
						if(! singletonHeadersNames.contains(header.getName())) {
							newRequest.addHeader(header);
						} else {
							newRequest.setHeader(header);
						}
					}
				} else {
					contactHeaderList = headerMap.get(headerName);
				}
			}
		}
		return contactHeaderList;
	}

	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#createResponseToOriginalRequest(javax.servlet.sip.SipSession, int, java.lang.String)
	 */
	public SipServletResponse createResponseToOriginalRequest(
			SipSession session, int status, String reasonPhrase) {

		if (session == null) {
			throw new NullPointerException("Null arg");
		}
		if(!session.isValid()) {
			throw new IllegalArgumentException("session is invalid !");
		}
		
		final MobicentsSipSession sipSession = (MobicentsSipSession) session;
		final Transaction trans = sipSession.getSessionCreatingTransaction();				
		final TransactionApplicationData appData = (TransactionApplicationData) trans.getApplicationData();
		
		final SipServletRequestImpl sipServletRequestImpl = (SipServletRequestImpl) appData.getSipServletMessage();
		if(RoutingState.FINAL_RESPONSE_SENT.equals(sipServletRequestImpl.getRoutingState())) {
			throw new IllegalStateException("subsequent response is inconsistent with an already sent response. a Final response has already been sent ! ");
		}
		return sipServletRequestImpl.createResponse(status, reasonPhrase);
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#getLinkedSession(javax.servlet.sip.SipSession)
	 */
	public SipSession getLinkedSession(final SipSession session) {
		if ( session == null) { 
			throw new NullPointerException("the argument is null");
		}
		if(!session.isValid()) {
			throw new IllegalArgumentException("the session is invalid");
		}
		final MobicentsSipSession mobicentsSipSession = (MobicentsSipSession)session;
		final SipSessionKey sipSessionKey = this.sessionMap.get(mobicentsSipSession.getKey());
		if(sipSessionKey == null) {
			dumpLinkedSessions();
			return null;
		}
		final MobicentsSipSession linkedSession = sipManager.getSipSession(sipSessionKey, false, null, mobicentsSipSession.getSipApplicationSession());
		if(logger.isDebugEnabled()) {
			if(linkedSession != null) {
				logger.debug("Linked Session found : " + linkedSession.getKey() + " for this session " + session.getId());
			} else {
				logger.debug("No Linked Session found for this session " + session.getId());
			}
		}
		if(linkedSession != null) {
			return linkedSession.getSession();
		} else {
			return null;
		}		
	}

	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#getLinkedSipServletRequest(javax.servlet.sip.SipServletRequest)
	 */
	public SipServletRequest getLinkedSipServletRequest(SipServletRequest req) {
		if ( req == null) { 
			throw new NullPointerException("the argument is null");
		}
		final MobicentsSipSession mobicentsSipSession = (MobicentsSipSession)req.getSession();
		final SipSessionKey sipSessionKey = this.sessionMap.get(mobicentsSipSession.getKey());
		if(sipSessionKey == null) {
			return null;
		}
		final MobicentsSipSession linkedSipSession = sipManager.getSipSession(sipSessionKey, false, null, mobicentsSipSession.getSipApplicationSession());
		if(linkedSipSession == null) {
			return null;
		}
		final SipServletRequest linkedSipServletRequest = originalRequestMap.get(linkedSipSession.getKey());
		return linkedSipServletRequest;
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#getPendingMessages(javax.servlet.sip.SipSession, javax.servlet.sip.UAMode)
	 */
	public List<SipServletMessage> getPendingMessages(SipSession session,
			UAMode mode) {
		if(!session.isValid()) {
			throw new IllegalArgumentException("the session is invalid!");
		}
		final MobicentsSipSession sipSessionImpl = (MobicentsSipSession) session;
		final List<SipServletMessage> retval = new ArrayList<SipServletMessage> ();
		if (mode.equals(UAMode.UAC)) {
			final Set<Transaction> ongoingTransactions = sipSessionImpl.getOngoingTransactions();
			if(ongoingTransactions != null) {
				for ( Transaction transaction: ongoingTransactions) {
					if ( transaction instanceof ClientTransaction) {
						final TransactionApplicationData tad = (TransactionApplicationData) transaction.getApplicationData();
						final SipServletMessage sipServletMessage = tad.getSipServletMessage();
						//not specified if ACK is a committed message in the spec but it seems not since Proxy api test
						//testCanacel101 method adds a header to the ACK and it cannot be on a committed message
						//so we don't want to return ACK as pending messages here. related to TCK test B2BUAHelper.testCreateRequest002
						if (!sipServletMessage.isCommitted() && !Request.ACK.equals(sipServletMessage.getMethod()) && !Request.PRACK.equals(sipServletMessage.getMethod())) {
							retval.add(sipServletMessage);
						}
						for(SipServletResponseImpl sipServletResponseImpl : tad.getSipServletResponses()) {
							if (!sipServletResponseImpl.isCommitted()) {
								retval.add(sipServletResponseImpl);
							}
						}
					}
				}
			}
			
		} else {
			for ( Transaction transaction: sipSessionImpl.getOngoingTransactions()) {
				if ( transaction instanceof ServerTransaction) {
					final TransactionApplicationData tad = (TransactionApplicationData) transaction.getApplicationData();
					final SipServletMessage sipServletMessage = tad.getSipServletMessage();
					//not specified if ACK is a committed message in the spec but it seems not since Proxy api test
					//testCanacel101 method adds a header to the ACK and it cannot be on a committed message
					//so we don't want to return ACK as pending messages here. related to TCK test B2BUAHelper.testCreateRequest002
					if (!sipServletMessage.isCommitted() && !Request.ACK.equals(sipServletMessage.getMethod())) {
						retval.add(sipServletMessage);
					}
				}
			}
		}
		return retval;
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#linkSipSessions(javax.servlet.sip.SipSession, javax.servlet.sip.SipSession)
	 */
	public void linkSipSessions(SipSession session1, SipSession session2) {
		if ( session1 == null) {
			throw new NullPointerException("First argument is null");
		}
		if ( session2 == null) {
			throw new NullPointerException("Second argument is null");
		}
		
		if(!session1.isValid() || !session2.isValid() || 
				State.TERMINATED.equals(((MobicentsSipSession)session1).getState()) ||
				State.TERMINATED.equals(((MobicentsSipSession)session2).getState()) ||
				!session1.getApplicationSession().equals(session2.getApplicationSession()) ||
				sessionMap.get(((MobicentsSipSession)session1).getKey()) != null ||
				sessionMap.get(((MobicentsSipSession)session2).getKey()) != null) {
			throw new IllegalArgumentException("either of the specified sessions has been terminated " +
					"or the sessions do not belong to the same application session or " +
					"one or both the sessions are already linked with some other session(s)");
		}
		this.sessionMap.put(((MobicentsSipSession)session1).getKey(), ((MobicentsSipSession)session2).getKey());
		this.sessionMap.put(((MobicentsSipSession)session2).getKey(), ((MobicentsSipSession) session1).getKey());
		dumpLinkedSessions();
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#unlinkSipSessions(javax.servlet.sip.SipSession)
	 */
	public void unlinkSipSessions(SipSession session) {		
		unlinkSipSessionsInternal(session, true);
	}
	
	/*
	 * (non-Javadoc)
	 * @see javax.servlet.sip.B2buaHelper#unlinkSipSessions(javax.servlet.sip.SipSession)
	 */
	public void unlinkSipSessionsInternal(SipSession session, boolean checkSession) {		
		if ( session == null) { 
			throw new NullPointerException("the argument is null");
		}
		final MobicentsSipSession key = (MobicentsSipSession) session;
		if(checkSession) {
			if(!session.isValid() || 
					State.TERMINATED.equals(key.getState()) ||
					sessionMap.get(key.getKey()) == null) {
				throw new IllegalArgumentException("the session is not currently linked to another session or it has been terminated");
			}		
		}
		final SipSessionKey value  = this.sessionMap.get(key.getKey());
		if (value != null) {
			this.sessionMap.remove(value);
		}
		this.sessionMap.remove(key.getKey());
		dumpLinkedSessions();
	}
	
	/**
	 * {@inheritDoc}
	 */
	public SipServletRequest createRequest(SipServletRequest origRequest) {
		try {
			final SipServletRequestImpl origRequestImpl = (SipServletRequestImpl) origRequest;
			final Request newRequest = (Request) origRequestImpl.message.clone();
			((SIPMessage)newRequest).setApplicationData(null);
			//removing the via header from original request
			newRequest.removeHeader(ViaHeader.NAME);	
			
			final FromHeader newFromHeader = (FromHeader) newRequest.getHeader(FromHeader.NAME); 
			
			//assign a new from tag
			newFromHeader.removeParameter("tag");
			//remove the to tag
			((ToHeader) newRequest.getHeader(ToHeader.NAME))
					.removeParameter("tag");
			// Remove the route header ( will point to us ).
			// commented as per issue 649
//			newRequest.removeHeader(RouteHeader.NAME);
			
			// Remove the record route headers. This is a new call leg.
			newRequest.removeHeader(RecordRouteHeader.NAME);
			
			//For non-REGISTER requests, the Contact header field is not copied 
			//but is populated by the container as usual
			if(!Request.REGISTER.equalsIgnoreCase(origRequest.getMethod())) {
				newRequest.removeHeader(ContactHeader.NAME);
			}
			//Creating new call id
			final ExtendedListeningPoint extendedListeningPoint = sipFactoryImpl.getSipNetworkInterfaceManager().getExtendedListeningPoints().next();
			final CallIdHeader callIdHeader = SipFactories.headerFactory.createCallIdHeader(extendedListeningPoint.getSipProvider().getNewCallId().getCallId());
			newRequest.setHeader(callIdHeader);
			
			final MobicentsSipSession originalSession = origRequestImpl.getSipSession();
			final MobicentsSipApplicationSession originalAppSession = originalSession
					.getSipApplicationSession();				
						
			newFromHeader.setTag(ApplicationRoutingHeaderComposer.getHash(sipFactoryImpl.getSipApplicationDispatcher(), originalSession.getKey().getApplicationName(), originalAppSession.getKey().getId()));
			
			final SipSessionKey key = SessionManagerUtil.getSipSessionKey(originalAppSession.getKey().getId(), originalSession.getKey().getApplicationName(), newRequest, false);
			final MobicentsSipSession session = ((SipManager)originalAppSession.getSipContext().getManager()).getSipSession(key, true, sipFactoryImpl, originalAppSession);			
			session.setHandler(originalSession.getHandler());
			
			final SipServletRequestImpl newSipServletRequest = new SipServletRequestImpl(
					newRequest,
					sipFactoryImpl,					
					session, 
					null, 
					null, 
					JainSipUtils.dialogCreatingMethods.contains(newRequest.getMethod()));			
			//JSR 289 Section 15.1.6
			newSipServletRequest.setRoutingDirective(SipApplicationRoutingDirective.CONTINUE, origRequest);			
			
			sessionMap.put(originalSession.getKey(), session.getKey());
			sessionMap.put(session.getKey(), originalSession.getKey());	
			dumpLinkedSessions();

			originalRequestMap.put(originalSession.getKey(), origRequest);
			originalRequestMap.put(session.getKey(), newSipServletRequest);						
			
			session.setB2buaHelper(this);
			originalSession.setB2buaHelper(this);
			
			return newSipServletRequest;
		} catch (Exception ex) {
			logger.error("Unexpected exception ", ex);
			throw new IllegalArgumentException(
					"Illegal arg ecnountered while creatigng b2bua", ex);
		}
	}

	/**
	 * {@inheritDoc}
	 */
	public SipServletRequest createCancel(SipSession session) {
		final SipServletRequest sipServletRequest = originalRequestMap.get(((MobicentsSipSession)session).getKey());
		
		final SipServletRequestImpl sipServletRequestImpl = (SipServletRequestImpl)sipServletRequest.createCancel();
		((MobicentsSipSession)sipServletRequestImpl.getSession()).setB2buaHelper(this);
		return sipServletRequestImpl;
	}

	/**
	 * @return the sipFactoryImpl
	 */
	public SipFactoryImpl getSipFactoryImpl() {
		return sipFactoryImpl;
	}

	/**
	 * @param sipFactoryImpl the sipFactoryImpl to set
	 */
	public void setSipFactoryImpl(SipFactoryImpl sipFactoryImpl) {
		this.sipFactoryImpl = sipFactoryImpl;
	}

	/**
	 * @return the sipManager
	 */
	public SipManager getSipManager() {
		return sipManager;
	}

	/**
	 * @param sipManager the sipManager to set
	 */
	public void setSipManager(SipManager sipManager) {
		this.sipManager = sipManager;
	}
	
	private void dumpLinkedSessions() {
		if(logger.isDebugEnabled()) {
			for (SipSessionKey key : sessionMap.keySet()) {
				logger.debug(key + " tied to session " + sessionMap.get(key));
			}
		}
	}
}