/**
* Creates a client transaction to handle a new request. Gets the real message channel from the
* superclass, and then creates a new client transaction wrapped around this channel.
*
* @param nextHop Hop to create a channel to contact.
*/
public MessageChannel createMessageChannel(int sourcePort, Hop nextHop)
throws UnknownHostException {
synchronized (clientTransactions) {
// New client transaction to return
SIPTransaction returnChannel;
// Create a new client transaction around the
// superclass' message channel
MessageChannel mc = super.createMessageChannel(sourcePort, nextHop);
// Superclass will return null if no message processor
// available for the transport.
if (mc == null) return null;
returnChannel = createClientTransaction(mc);
clientTransactions.add(0, (SIPClientTransaction) returnChannel);
((SIPClientTransaction) returnChannel).setViaPort(nextHop.getPort());
((SIPClientTransaction) returnChannel).setViaHost(nextHop.getHost());
// Add the transaction timer for the state machine.
returnChannel.startTransactionTimer();
return returnChannel;
}
}
/**
* Return addresses for default proxy to forward the request to. The list is organized in the
* following priority. If the requestURI refers directly to a host, the host and port information
* are extracted from it and made the next hop on the list. If the default route has been
* specified, then it is used to construct the next element of the list. <code>
* RouteHeader firstRoute = (RouteHeader) req.getHeader( RouteHeader.NAME );
* if (firstRoute!=null) {
* URI uri = firstRoute.getAddress().getURI();
* if (uri.isSIPUri()) {
* SipURI nextHop = (SipURI) uri;
* if ( nextHop.hasLrParam() ) {
* // OK, use it
* } else {
* nextHop = fixStrictRouting( req ); <--- Here, make the modifications as per RFC3261
* }
* } else {
* // error: non-SIP URI not allowed in Route headers
* throw new SipException( "Request has Route header with non-SIP URI" );
* }
* } else if (outboundProxy!=null) {
* // use outbound proxy for nextHop
* } else if ( req.getRequestURI().isSipURI() ) {
* // use request URI for nextHop
* }
*
* </code>
*
* @param request is the sip request to route.
*/
public Hop getNextHop(Request request) throws SipException {
SIPRequest sipRequest = (SIPRequest) request;
RequestLine requestLine = sipRequest.getRequestLine();
if (requestLine == null) {
return defaultRoute;
}
javax.sip.address.URI requestURI = requestLine.getUri();
if (requestURI == null) throw new IllegalArgumentException("Bad message: Null requestURI");
RouteList routes = sipRequest.getRouteHeaders();
/*
* In case the topmost Route header contains no 'lr' parameter (which
* means the next hop is a strict router), the implementation will
* perform 'Route Information Postprocessing' as described in RFC3261
* section 16.6 step 6 (also known as "Route header popping"). That is,
* the following modifications will be made to the request:
*
* The implementation places the Request-URI into the Route header field
* as the last value.
*
* The implementation then places the first Route header field value
* into the Request-URI and removes that value from the Route header
* field.
*
* Subsequently, the request URI will be used as next hop target
*/
if (routes != null) {
// to send the request through a specified hop the application is
// supposed to prepend the appropriate Route header which.
Route route = (Route) routes.getFirst();
URI uri = route.getAddress().getURI();
if (uri.isSipURI()) {
SipURI sipUri = (SipURI) uri;
if (!sipUri.hasLrParam()) {
fixStrictRouting(sipRequest);
if (sipStack.isLoggingEnabled())
sipStack.getStackLogger().logDebug("Route post processing fixed strict routing");
}
Hop hop = createHop(sipUri, request);
if (sipStack.isLoggingEnabled())
sipStack.getStackLogger().logDebug("NextHop based on Route:" + hop);
return hop;
} else {
throw new SipException("First Route not a SIP URI");
}
} else if (requestURI.isSipURI() && ((SipURI) requestURI).getMAddrParam() != null) {
Hop hop = createHop((SipURI) requestURI, request);
if (sipStack.isLoggingEnabled())
sipStack
.getStackLogger()
.logDebug("Using request URI maddr to route the request = " + hop.toString());
// JvB: don't remove it!
// ((SipURI) requestURI).removeParameter("maddr");
return hop;
} else if (defaultRoute != null) {
if (sipStack.isLoggingEnabled())
sipStack
.getStackLogger()
.logDebug("Using outbound proxy to route the request = " + defaultRoute.toString());
return defaultRoute;
} else if (requestURI.isSipURI()) {
Hop hop = createHop((SipURI) requestURI, request);
if (hop != null && sipStack.isLoggingEnabled())
sipStack.getStackLogger().logDebug("Used request-URI for nextHop = " + hop.toString());
else if (sipStack.isLoggingEnabled()) {
sipStack.getStackLogger().logDebug("returning null hop -- loop detected");
}
return hop;
} else {
// The internal router should never be consulted for non-sip URIs.
InternalErrorHandler.handleException(
"Unexpected non-sip URI", this.sipStack.getStackLogger());
return null;
}
}