--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/inc/nspsessionobserver.h	Tue Feb 02 01:04:58 2010 +0200
@@ -0,0 +1,97 @@
+/*
+* Copyright (c) 2007 Nokia Corporation and/or its subsidiary(-ies).
+* All rights reserved.
+* This component and the accompanying materials are made available
+* under the terms of "Eclipse Public License v1.0"
+* which accompanies this distribution, and is available
+* at the URL "http://www.eclipse.org/legal/epl-v10.html".
+*
+* Initial Contributors:
+* Nokia Corporation - initial contribution.
+*
+* Contributors:
+*
+* Description:    Session observer class, implemented by plugin client.
+*
+*/
+
+
+
+#ifndef NSPSESSIONOBSERVER_H
+#define NSPSESSIONOBSERVER_H
+
+#include <e32def.h>
+
+class CSdpDocument;
+
+/**
+ * Error limit which can be used to signal situations where Nat failed in
+ * asynchronous prosessing, and resume of normal SIP signaling is expected.
+ * All errors below this limit are considered as non-fatal, and normal SIP
+ * session is maintained without informing MCE Client.
+ */
+const TInt KNatNonFatalErrorLimit = -11000;
+
+/**
+ *  Session observer, implemented by plugin client to receive async calls.
+ *
+ *  @lib natfwsdpprovider.dll
+ *  @since S60 3.2
+ */
+class MNSPSessionObserver
+    {
+public: // New functions
+    
+    /**
+     * Callback for signaling that session is initialized, and ready for use.
+     */
+    virtual void Initialized( TUint aSessionId ) = 0;
+    
+    /**
+     * Callback for signaling that Offer is modified to point NAT.
+     *
+     * @param   aSessionId       Session unique identier.
+     * @param   aOffer           Modified Offer, ownership transferred.
+     */
+    virtual void OfferReady( TUint aSessionId, CSdpDocument* aOffer ) = 0;
+    
+    /**
+     * Callback for signaling that Answer is modified to point NAT.
+     *
+     * @param   aSessionId       Session unique identier.
+     * @param   aAnswer          Modified Answer, ownership transferred.
+     */
+    virtual void AnswerReady( TUint aSessionId, CSdpDocument* aAnswer ) = 0;
+    
+    /**
+     * Callback for signaling that NAT negotiation has resulted
+     * a different result than original SDP A/O. Hence updated SDP content
+     * must be sent. Only Controlling agent receives this callback.
+     *
+     * @param   aSessionId       Session unique identier.
+     * @param   aOffer           Last SDP document, but with modified content.
+     *                           Ownership transferred.
+     */
+    virtual void UpdateSdp( TUint aSessionId, CSdpDocument* aOffer ) = 0;
+    
+    /**
+     * Session errors. Session which is identified by aSessionId is deleted.
+     *
+     * @param   aSessionId       Session unique identier.
+     * @param   aError           System wide error code.
+     */
+    virtual void ErrorOccurred( TUint aSessionId, TInt aError ) = 0;
+
+    /**
+     * Session media related ICMP error occured.
+     *
+     * @param   aSessionId       Session unique identier.
+     * @param   aError           ICMP error code.
+     */
+    virtual void IcmpErrorOccurred( TUint aSessionId, TInt aError ) = 0;
+    
+    };
+
+#endif // NSPSESSIONOBSERVER_H
+
+// end of file