// Copyright (c) 2004-2009 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:

// dns.h - name resolver DNS client module header

//

#ifndef __DNS_H__

#define __DNS_H__

/**

@file dns.h

DNS protocol proviver

@internalComponent	Domain Name Resolver

*/

#include "listener.h"

#include "message.h"

#include "dns_sock.h"

#include "hostname.h"

#ifdef EXCLUDE_SYMBIAN_DNS_PUNYCODE

#undef SYMBIAN_DNS_PUNYCODE

#endif //EXCLUDE_SYMBIAN_DNS_PUNYCODE

const TUint KDndNumRequests = KDndNumResolver * 2;

class CDndRecord;

class CDndDnsclient;

class CDndCache;

/**

// @brief	The request data

//

// TDndReqData is the DNS protocol side of the <b>query session</b> used by a

// <b>resolver</b>. The <b>resolvers</b> side is only visible via the MDnsResolver

// callback class. On the other hand, the visible services of this class

// for the resolver (CDndResolver) are defined by the MDnsSession. 

*/

class TDndReqData : public TDnsRequest, public MDnsSession, public MDnsServerListNotify

	{

public:

	//

	// MDnsSession API (methods callable by resolver)

	// (documented in the mixin class)

	virtual TInt NewQuery(const TDnsMessage &aQuery, TDnsServerScope aServerScope, TUint32 aFlags);

	virtual void CancelQuery();

	virtual TInt DoQueryL(const TTime &aRequestTime, const EDnsQType aQType);

	virtual TInt DoNext(TDnsMessageBuf &aReply, TInt aNext) const;

	void DoError(TInt aError, TUint aTTL);

	virtual TBool PickNewServer();

	virtual TBool PickDefaultServer();

	void Close();

	//

	// MDnsServerListNotify callback

	//

	// The notify callback from the server manager

	virtual void ServerListComplete(const TDnsServerFilter &aFilter, TInt aResult);

	//

	// Upcalls from DNS Socket

	//

	// Build a complete DNS message from request data

	virtual TBool Build(CDnsSocket &aSource, TMsgBuf &aBuf, TInetAddr &aServer, TInt aMaxMessage);

	// Handle a reply message for the request (request remains queued)

	virtual TBool Reply(CDnsSocket &aSource, const TMsgBuf &aBuf, const TInetAddr &aServer);

	// The message has been sent (request remains queued)

	virtual void Sent(CDnsSocket &aSource);

	// The request has been aborted (not queued anymore)

	virtual void Abort(CDnsSocket &aSource, const TInt aReason);

	// Generate the callback event for the resolver owning this request

	void SendResponse(TInt aErr);

protected:

	//

	// Internal utilities

	//

	// Check the message question against request data

	TInt CheckQuestion(const TMsgBuf &aMsg, TInt &aRCode) const;

	// Check request against responce and translate RCODE value.

	TInt TranslateRCODE(const TDndHeader &aHdr, TInt aRCode) const;

	// Build a TNameRecord record from a RR

	TInt GetResponse(const TDndRR &aRR, TNameRecord &aReply) const;

	// Update DNS reply into cache

	TBool UpdateCacheData(const TMsgBuf &aMsg, const TInt aAnswerOffset, const TInt aErr);

	// Return instance ptr of the actual class instance

	virtual const void *const Instance() const {return this; }

public:

	TUint iIsReqPending:1;	//< Resolver is waiting for a reply

	TUint iIsUsingTCP:1;	//< Set when TCP is in use, only a safeguard against bad DNS servers.

	TUint iIsNewQuery:1;	//< Set in NewQuery, cleared in DoQuery (used in deciding whether a new ID is needed)

	TUint iIsFromCache:1;	//< Set if iRecord was from cached

	TUint iOpcode:4;		//< OPCODE field of the header

#ifdef SYMBIAN_DNS_PUNYCODE

	TUint iIdnEnabled:1;	//< =1, support for IDN is enabled for this request.

#endif //SYMBIAN_DNS_PUNYCODE

	TUint16 iQdCount;

	TUint32 iFlags;			//< Mofidier flags for the query (RD, PQ etc).

	TDndQuestion iQuestion;	//< Query Information

	TDnsServerFilter iFilter;

	TUint32 iCurrentServer;

	CDndRecord *iRecord;	//< Pointer to the record in the cache is stored here when a DNS query

							//< is sent - for quick update of cache.

	// Callback section

	MDnsResolver *iCallback;

	// "Owner" source

	CDndDnsclient *iOwner;	//< Actual owner of the request data

	TUint iNetworkId;      //< NetworkId from the request message.	

	};

class TInetAddressInfo;

class CDndDnsclient : public CDnsSocket, public MDnsSource

    {

	friend class CDndMonitor;

	friend class TDndReqData;

protected:

	CDndDnsclient(CDndEngine &aControl, MDnsServerManager &aServerManager);

	void ConstructL();

public:

	static CDndDnsclient *NewL(CDndEngine &aControl, MDnsServerManager &aServerManager);

	void HandleCommandL(TInt aCommand);

	virtual ~CDndDnsclient();

	// Configuration has changed

	virtual void ConfigurationChanged() = 0;

	// Assign a session slot

	MDnsSession *OpenSession(MDnsResolver *const aCallback);

	// Check if there is a route and valid source address for the aDestination

	TInt CheckAddress(const TInetAddr &aDestination);

	// Resolver has received a query from application

	void QueryBegin();

	// Resolver has completed the query from application

	void QueryEnd();

protected:

	// Received a Query Message from some server -- ignore by default

	void Query(const TMsgBuf &/*aBuf*/, const TInetAddr &/*aServer*/, const RSocket &/*aSocket*/) {}

	// Received an error indication for a server

	void Error(const TInetAddr &aServer, TInt aError);

	inline void ActivateSocketL(TUint aNetworkId = 0) { CDnsSocket::ActivateSocketL(aNetworkId); } // lint placebo

	CDndEngine &iControl;					//< The DND Engine

	MDnsServerManager &iServerManager;		//< The server manager

	TDndReqData	iDndReqData[KDndNumRequests];	//< Requests being served

	TUint iActivityCount;			//< Count of activity, shut DNS sockets when ZERO.

	CDndCache *iCache;				//< The Cache

	THostNames iHostNames;			//< The current hostnames

	};

#endif