// Copyright (c) 2008-2009 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:

// dnsproxymessageproc.cpp

// This class constructs the response packet for matched query packet that

// it gets from the queue. First it will get the name from the database

// checks against the query name. If it matched then generates the answer for

// query packet and appends into buffer then sends to querying host. Otherwise

// generates the authoritive answer and sends back to querying hosts.

//

/**

 @file

 @internalTechnology

*/

#include <e32base.h>

#include <e32math.h>

#include <e32des8.h> 

#include <e32debug.h> 

#include <utf.h>

#include "dns_qry_internal.h"

#include "inet6log.h"

#include "dnsproxymsgproc.h"

#include "dnsproxylistener.h"

#include "dnsproxyengine.h"

#include "message.h"

#include "dnsproxylog.h"

CDnsProxyMessageProcessor* CDnsProxyMessageProcessor::NewL(CDnsProxyListener& aListener)

/**

 * This is the two phase construction method and is leaving function

 * @param aListener - reference CDnsProxyListener class

 *

 * @internalTechnology

 **/

	{

	CDnsProxyMessageProcessor* response = new(ELeave) CDnsProxyMessageProcessor(aListener);

	return response;

	}

CDnsProxyMessageProcessor::CDnsProxyMessageProcessor(CDnsProxyListener& aListener):iListener(aListener),iAntype(0)

/**

 * This is the constructor for this class

 * @param aListener - reference CDnsProxyListener class

 * @return - None

 *

 * @internalTechnology

 **/

	{

	}

CDnsProxyMessageProcessor::~CDnsProxyMessageProcessor()

/**

 * This is the destructor  and deletes all the member variables and thus

 * releases all the memory assosicated with those objects

 * @param - None

 * @return - None

 *

 * @internalTechnology

 **/

	{

	}

void CDnsProxyMessageProcessor::GetDnsFailureMessage(TMsgBuf& aMsgBuf)

/**

 * This is create DNS Failure message

 * @param - TMsgBuf&

 * @return - None

 *

 * @internalTechnology

 **/

	{

	TDndHeader &hdr = aMsgBuf.Header();

	hdr.SetQR(1);

	//set dns server failure

	hdr.SetRCode(2);

	}

void CDnsProxyMessageProcessor::GetLocalDnsResponseL(TMsgBuf& aMsgbuf)

/**

 * This function constructs the response packet. First it gets the 

 * only query name by filtering the qtype and qclass then it tries to

 * match the names. If it matches then, generates the ANResource reord 

 * otherwise generates the NSResource Record.

 * @param -aMsg - Query packet

 * @internalTechnology

 **/

	{

	TDndQuestion qDns;

	qDns.Create(aMsgbuf, sizeof(TDndHeader));

	TBuf<KDnsMaxName> queryName;

	TInt ret_val = qDns.GetName(queryName);

	if(ret_val==KErrNone)

		{

		HBufC8* q_name = CnvUtfConverter::ConvertFromUnicodeToUtf8L(queryName);

		CleanupStack::PushL(q_name);

		TPtrC8 qname = q_name->Right(q_name->Length());

		EDnsQType iQType = qDns.QType();

		switch(qDns.QType())

			{

				case EDnsQType_A:

					{

					TDnsProxydbElement* element;

					TDndHeader& hdr = aMsgbuf.Header();

					CDnsProxyEngine& engine = iListener.GetDnsProxyEngine();

					element = engine.iDnsproxydb->GetRecordList(qname);

					if(element)

						{

						hdr.SetNsCount(0);

						GetRecordsFromDb(aMsgbuf,*element);

						}

					else	

						{

						SetQHeaderBits(hdr);

						hdr.SetNsCount(1);

						GetNsRecordSetL(aMsgbuf);

						}	

					}

					break;

				case EDnsQType_PTR:

					{

					TDnsProxydbElement* element = NULL;

					element = LookupPTRInDb(aMsgbuf);

	                if(element)

	                    {           

	                    GetPTRRecord(aMsgbuf,element->iHostName);

	                    }

					}

					break;

			}

			CleanupStack::PopAndDestroy(q_name);

		}

	}

void CDnsProxyMessageProcessor::SetQHeaderBits(TDndHeader& aHdr)

/**

 * This will set bits fileds of query header as required for 

 * response message

 * @param aHdr - reference to header section of query

 * @internalTechnology

 **/	

	{

	TInt aId = aHdr.ID();

	aHdr.SetId(aId);

	aHdr.SetQR(1);

	aHdr.SetOpcode(0);

	aHdr.SetAA(0);

	aHdr.SetRCode(0);

	TInt qdcount = aHdr.QDCOUNT();

	aHdr.SetQdCount(qdcount);

	aHdr.SetArCount(0);

	}

void CDnsProxyMessageProcessor::GetRecordsFromDb(TMsgBuf& aMsg,TDnsProxydbElement& aElement)

/**

 * This will give constructed response message for given query

 * @param aMsg - query 

 * @param - aElement - reference to TDnsProxydbElement class

 * @internalTechnology

 *

 **/	

	{

	iAntype =0;

	TDndHeader &hdr = aMsg.Header();

	SetQHeaderBits(hdr);

	TInt hdr_id = hdr.ID();

	if(aElement.iRecord.Length()==0)

		{

		GetAnRecordSet(aMsg,aElement);

		}

	else

		{

		TBuf8<KDnsMaxMessage>record;

		record = aElement.iRecord;

		aMsg = TMsgBuf::Cast(record);

		TDndHeader& header = aMsg.Header();

		TInt hdid = header.ID();

		LOG(Log::Printf(_L("\t \n --- Transaction Id:[%d]"),hdid));

		header.SetId(hdr_id);

		TUint16 qtype = aElement.iDnsQType;

		if(qtype==EDnsType_A)

			iAntype++;

		}

	hdr.SetAnCount(iAntype);

	hdr.SetNsCount(0);

	}

void CDnsProxyMessageProcessor::GetAnRecordSet(TMsgBuf& aQMsg,TDnsProxydbElement& aElement)

/**

 * Constructs answer resource record/s and appends it to buffer

 * @param -  aQMsg, dns query message

 * @param -  aElement, reference to TDnsProxydbElement class

 * @leave - system wide errors, buffer overflow

 * @internalTechnology

 **/	

	{

	CDnsProxyEngine& engine = iListener.GetDnsProxyEngine();

	aQMsg.Header();

	TInetAddr address = aElement.iHostAddr;

	THostName name;

	aQMsg.GetName(sizeof(aQMsg.Header()),name);	

	TDndQuestion question;

	TInt index = question.Create(aQMsg,sizeof(aQMsg.Header()));

	TInt len = aQMsg.Length();

	TDndRROut rrout(aQMsg);

	TDnsProxyConfigParams iEngineConfig = iListener.GetDnsProxyEngine().GetConfig();

	rrout.iType = (TUint16)question.QType();

	rrout.iClass = (TUint16)question.QClass();

	rrout.iTTL = iEngineConfig.iTTL;

	TInt ret = rrout.Append(KNullDesC8, sizeof(TDndHeader));

	iAntype++;

	rrout.AppendRData(address);

	engine.iDnsproxydb->AddRRecord(aElement,aQMsg,question.QType());			

	}

void CDnsProxyMessageProcessor::GetNsRecordSetL(TMsgBuf& aMsg)

/**

 * constructs and appends the authoritive resource records

 * @param -  aQMsg, dns query message

 * @leave - system wide errors, buffer overflow

 *

 * @internalTechnology

 **/

	{

	TDnsProxyNsRecord nsrecord;

	TBuf8<KDnsMaxMessage> record;

	//read from TTL from config

	CDnsProxyEngine& engine = iListener.GetDnsProxyEngine();

	TUint ttl =  engine.GetConfig().iTTL;

	//Create RBuf

	RBuf8 qname;

	TInt offset = sizeof(TDndHeader);

	const TUint8* ptr = (aMsg.Ptr() + offset);

	TPtrC8 ptrc8(aMsg.Ptr() + offset, aMsg.Size() - offset);

	qname.Create(ptrc8.Size());

	CleanupClosePushL(qname);

	qname.Copy(TPtrC8(&ptr[0],ptrc8.Size()));

	nsrecord.ResetBuffer();

	nsrecord.iQType = EDnsType_SOA;

	nsrecord.iCType = EDnsClass_IN;

	nsrecord.iTTL = ttl;

	nsrecord.iSerialNum 	= engine.iConfigParams.iSerialNum;

	nsrecord.iRefreshTime	= engine.iConfigParams.iRefreshTime;

	nsrecord.iRetryTime		= engine.iConfigParams.iRetryTime;

	nsrecord.iExpiretime	= engine.iConfigParams.iExpiretime;

	record = nsrecord.CreateNSResourceRecord(qname);

	aMsg.Append(record);

	CleanupStack::PopAndDestroy(&qname);

	}

TInt CDnsProxyMessageProcessor::GetQNameSuffixL(TMsgBuf& aMsg)

/**

 * This function gets the suffix of recieved query

 * @param aMsg - reference to dns query message

 * @return ret_val - represents whether query is local or global query

 *

 * @internalTechnology

 **/

	{

    CDnsProxyEngine& engine = iListener.GetDnsProxyEngine();

	TInt retVal = KGlobalQuery;

	/*In case suffix information is not available

	  treat it as global query no need of comparison*/

	if(!engine.IsSuffixAvailable())

	    return retVal;

	TDndQuestion qDns;

	qDns.Create(aMsg, sizeof(TDndHeader));

	EDnsQType iQType = qDns.QType();

	switch (qDns.QType()) 

		{

		case EDnsQType_A:

			{

			TBuf<KMaxName> buf;

			buf.Copy(engine.iSuffixInfo);

			HBufC8* nsuffix = CnvUtfConverter::ConvertFromUnicodeToUtf8L(buf);

			CleanupStack::PushL(nsuffix);	

			TPtrC8 qsuffix = nsuffix->Right(nsuffix->Length());

			TBuf<KDnsMaxName> queryName;

			TInt err = qDns.GetName(queryName);

			if(err == KErrNone)

				{

				HBufC8* new_name = CnvUtfConverter::ConvertFromUnicodeToUtf8L(queryName);

				TPtrC8 qname = new_name->Right(new_name->Length());

				if(qname.Length() > qsuffix.Length())

					{

					TPtrC8 suffix = qname.Mid((qname.Length())-(qsuffix.Length()),qsuffix.Length());

					TInt errVal = suffix.Compare(qsuffix);

					if(errVal==KErrNone)

						{

						retVal = KLocalQuery;

						__LOG("Processing Local Query-Type-A");

						}

					else

						__LOG("Processing Global Query-Type-A");	

					}

				delete new_name;

				}

			CleanupStack::PopAndDestroy(nsuffix);	

			}

			break;

		case EDnsQType_PTR:

			{

			TDnsProxydbElement* element = NULL;			

			element = LookupPTRInDb(aMsg);

			if(element)

				{

				retVal = KLocalQuery;

				}

			else 

				{

				retVal = KGlobalQuery;

				}

			}

			break;

		default:

			{

			retVal = KGlobalQuery;

			}

		} // end switch

	return retVal;

	}

TDnsProxydbElement* CDnsProxyMessageProcessor::LookupPTRInDb(TMsgBuf& aMsg)

/**

* Looksup in db for existance of the recod. If present then process query as local

* otherwise treats PTR query as a global one

* @param aMsg - Query Message

* @return TDnsProxydbElement - pointer to TDnsProxydbElement object

*

**/

	{

	CDnsProxyEngine& engine = iListener.GetDnsProxyEngine();

	TBuf<KPTRSufix>ptrbuf;

	ptrbuf.Copy(KPTRSUFFIX);

	TDndQuestion qDns;

	qDns.Create(aMsg, sizeof(TDndHeader));

	TBuf<KDnsMaxName> queryName;

	TInt flag = qDns.GetName(queryName);

	TDnsProxydbElement* element = NULL;

	if(queryName.Length()>ptrbuf.Length())

		{

		TPtrC16 ipaddr = queryName.Mid(0,(queryName.Length()-(ptrbuf.Length()+1)));

		TInetAddr address;

		address.Input(ipaddr);

		TUint32 ad = address.Address();

		TUint32 swapaddr =(((ad&0x000000FF)<<24)+((ad&0x0000FF00)<<8)+

	   					  ((ad&0x00FF0000)>>8)+((ad&0xFF000000)>>24));

		TInetAddr inetaddr;

		inetaddr.SetAddress(swapaddr);

		element = engine.iDnsproxydb->FindIpAddress(inetaddr);

		}

	return element;

	}

void CDnsProxyMessageProcessor::GetPTRRecord(TMsgBuf& aMsg,const TDesC8& aName)

/**

* Constructs PTR record and appends to TMsgBuf

* @param aMsg - Query Message

* @param aElement - reference to TDnsProxydbElement class which matched to query name

*

* @internalTechnology

**/

	{

	TDndHeader &hdr = aMsg.Header();

	SetQHeaderBits(hdr);

	hdr.SetAA(1);

	hdr.SetAnCount(1);

	TDndQuestion question;

	TInt index = question.Create(aMsg,sizeof(TDndHeader));

	TInt len = aMsg.Length();

	TDndRROut rrout(aMsg);

	rrout.iType = (TUint16)question.QType();

	rrout.iClass = (TUint16)question.QClass();

	rrout.iTTL = iListener.GetDnsProxyEngine().GetConfig().iTTL;

	TInt ret = rrout.Append(KNullDesC8, sizeof(TDndHeader));

	TInt err = rrout.AppendRData(aName,0);

	}

TDesC8& TDnsProxyNsRecord::CreateNSResourceRecord(const TDesC8& aMsg)

/**

 * Creates new authorative answer record for given query. This will be 

 * generated when ther is no matching name found in db

 * @param aMsg - Dns query 

 * @return iNSBuf - buffer having constructed authorative answer record

 *

 * @internalTechnology

 **/	

	{

	TInt offset_pos = aMsg.Locate(0);

	const TUint8* ptr8 = (aMsg.Ptr());

	TBufC8<KDnsMaxMessage> abuf_ns = TPtrC8(&ptr8[0],offset_pos);

	iNSBuf.Append(abuf_ns);

	//this will identify the termination of the QName

	iNSBuf.Append((TChar)0);

	iNSBuf.Append(iQType/0x100);

	iNSBuf.Append(iQType%0x100);

	iNSBuf.Append(iCType/0x100);

	iNSBuf.Append(iCType%0x100);

	AppendTTLBuf();

	AppendRRLength(aMsg);

	return iNSBuf;

	}

void TDnsProxyNsRecord::AppendTTLBuf()

/**

 * Appends the TTL to ns record set

 *

 * @internalTechnology

 **/

	{

	iNSBuf.Append((TChar)(iTTL / 0x1000000));

	iNSBuf.Append((TChar)((iTTL / 0x10000) % 0x100));

	iNSBuf.Append((TChar)((iTTL / 0x100) % 0x100));

	iNSBuf.Append((TChar)(iTTL % 0x100));

	}

void TDnsProxyNsRecord::AppendRRLength(const TDesC8& aMsg)

/**

 * This function creates the NS Resource Record as specified in

 * the RFC1035 section 3.3.13.-SOA RDATA Format

 * @param - aMsg ,reference to buf which will have ns record set

 *

 * @internalTechnology

 **/

	{

	TBuf8<KDnsMaxMessage> buf;

	buf.Append(aMsg);

	buf.Append((TChar)0);

	buf.Append(aMsg);

	buf.Append((TChar)0);

	buf.Append((TChar)(iSerialNum / 0x1000000));

	buf.Append((TChar)((iSerialNum / 0x10000) % 0x100));

	buf.Append((TChar)((iSerialNum / 0x100) % 0x100));

	buf.Append((TChar)(iSerialNum % 0x100));

	buf.Append((TChar)(iRefreshTime / 0x1000000));

	buf.Append((TChar)((iRefreshTime / 0x10000) % 0x100));

	buf.Append((TChar)((iRefreshTime / 0x100) % 0x100));

	buf.Append((TChar)(iRefreshTime % 0x100));

	buf.Append((TChar)(iRetryTime / 0x1000000));

	buf.Append((TChar)((iRetryTime / 0x10000) % 0x100));

	buf.Append((TChar)((iRetryTime / 0x100) % 0x100));

	buf.Append((TChar)(iRetryTime % 0x100));

	buf.Append((TChar)(iExpiretime / 0x1000000));

	buf.Append((TChar)((iExpiretime / 0x10000) % 0x100));

	buf.Append((TChar)((iExpiretime / 0x100) % 0x100));

	buf.Append((TChar)(iExpiretime % 0x100));

	buf.Append((TChar)(iTTL / 0x1000000));

	buf.Append((TChar)((iTTL / 0x10000) % 0x100));

	buf.Append((TChar)((iTTL / 0x100) % 0x100));

	buf.Append((TChar)(iTTL % 0x100));

	TInt len = buf.Size();

	iNSBuf.Append((TChar)(len/0x0100));

	iNSBuf.Append((TChar)(len%0x0100));

	iNSBuf.Append(buf);

	}