williamr@2: // Copyright (c) 2004-2009 Nokia Corporation and/or its subsidiary(-ies).
williamr@2: // All rights reserved.
williamr@2: // This component and the accompanying materials are made available
williamr@4: // under the terms of "Eclipse Public License v1.0"
williamr@2: // which accompanies this distribution, and is available
williamr@4: // at the URL "http://www.eclipse.org/legal/epl-v10.html".
williamr@2: //
williamr@2: // Initial Contributors:
williamr@2: // Nokia Corporation - initial contribution.
williamr@2: //
williamr@2: // Contributors:
williamr@2: //
williamr@2: // Description:
williamr@2: // in_chk.h - IPv6/IPv4 checksum module
williamr@2: // Raw Internet Checksum computation from RMBufChain.
williamr@2: //
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: /**
williamr@2:  @file in_chk.h
williamr@2:  @publishedAll
williamr@2:  @released
williamr@2: */
williamr@2: 
williamr@2: #ifndef __IN_CHK_H__
williamr@2: #define __IN_CHK_H__
williamr@2: 
williamr@2: #include "in_pkt.h"
williamr@4: class RMBufChain;
williamr@4: class RMBufPktInfo;
williamr@2: 
williamr@2: /** Checksum calculation.
williamr@2: 
williamr@2: @publishedAll
williamr@2: @released
williamr@2: */
williamr@2: class TChecksum {
williamr@2: public:
williamr@2:         // TChecksum can be initialized with an old inverted checksum
williamr@4:         TChecksum(TUint16 aSum = ~0) : iSum((TUint16)~aSum) {}
williamr@2: 	inline void Init(TUint16 aSum = ~0);
williamr@2: 
williamr@2: 	inline TUint32 Sum();
williamr@2:         inline TUint32 Sum32();
williamr@2:         inline void Fold();
williamr@2:         inline void Reverse();
williamr@2: 
williamr@2:         // Complex Add methods
williamr@2:         IMPORT_C void Add(RMBufChain &aPacket, TInt aOffset);
williamr@2:         IMPORT_C void Add(RMBufChain &aPacket, const RMBufPktInfo *aInfo, TInt aOffset);
williamr@2: 
williamr@2:         // Inline Add methods
williamr@2:         inline void Add(const TUint16 *aPtr, TInt aLength);
williamr@2:         inline void AddHi(TUint8 aByte);
williamr@2:         inline void AddLo(TUint8 aByte);
williamr@2:         inline void Add(TUint16 aHalfWord);
williamr@2:         inline void Add(TUint32 aWord);
williamr@2:         inline void AddH(TUint16 aHalfWord);
williamr@2:         inline void AddH(TUint32 aWord);
williamr@2: 
williamr@2:         // Static methods
williamr@2:         static inline TUint32 Fold(TUint32 aSum);
williamr@2:         static inline TUint16 ComplementedFold(TUint32 aSum);
williamr@2:         IMPORT_C static TUint32 Calculate(const TUint16 *aPtr, TInt aLength);
williamr@2: 
williamr@2: private:
williamr@2: 	TUint32	iSum;   // 32-bit sum in network byte order
williamr@2: };
williamr@2: 
williamr@2: 
williamr@2: /**
williamr@2: // TInet6Checksum Template.
williamr@2: //
williamr@2: //		This template class provides utilitlies to compute and check
williamr@2: //		IPv6 Upper Layer Checksums
williamr@2: //		These are not merged with the TInet6Packet class, because that
williamr@2: //		class is intended (and is used) for all headers, not just upper
williamr@2: //		layers.
williamr@2: //
williamr@2: //	The template parameter (Header class) must
williamr@2: //		- have Checksum() method
williamr@2: //		- have SetChecksum() method
williamr@2: //		- the checkum in header must be aligned to 16 bit word
williamr@2: //
williamr@2: // @publishedAll
williamr@2: // @released
williamr@2: */
williamr@2: template <class T>
williamr@2: class TInet6Checksum : public TInet6Packet<T>
williamr@2: 	{
williamr@2: public:
williamr@2: 	TInet6Checksum() {}
williamr@2: 	TInet6Checksum(RMBufChain &aPacket) : TInet6Packet<T>(aPacket) {}
williamr@2: 	TInet6Checksum(RMBufChain &aPacket, TInt aOffset) : TInet6Packet<T>(aPacket, aOffset) {}
williamr@2: 	void ComputeChecksum(RMBufChain &aPacket, const RMBufPktInfo *aInfo, TInt aOffset = 0);
williamr@2: 	TBool VerifyChecksum(RMBufChain &aPacket, const RMBufPktInfo *aInfo, TInt aOffset = 0);
williamr@2: 	void ComputeChecksum();
williamr@2: 	TBool VerifyChecksum();
williamr@2: 	};
williamr@2: 
williamr@2: //
williamr@2: // Inline methods for TChecksum
williamr@2: //
williamr@2: 
williamr@2: inline void TChecksum::Init(TUint16 aSum)
williamr@2: {
williamr@2:         iSum = ~aSum & 0xffff;
williamr@2: }
williamr@2: 
williamr@2: inline void TChecksum::Add(const TUint16 *aPtr, TInt aLength)
williamr@2: {
williamr@2: 	iSum += Calculate(aPtr, aLength);
williamr@2: }
williamr@2: 
williamr@2: inline void TChecksum::AddHi(TUint8 aByte)
williamr@2: {
williamr@2:         iSum += (aByte << 8);
williamr@2: }
williamr@2: 
williamr@2: inline void TChecksum::AddLo(TUint8 aByte)
williamr@2: {
williamr@2:         iSum += aByte;
williamr@2: }
williamr@2: 
williamr@2: // Add halfword in network byte order
williamr@2: inline void TChecksum::Add(TUint16 aHalfWord)
williamr@2: {
williamr@2:         iSum += aHalfWord;
williamr@2: }
williamr@2: 
williamr@2: // Add word in network byte order
williamr@2: inline void TChecksum::Add(TUint32 aWord)
williamr@2: {
williamr@2: 	iSum += aWord >> 16;
williamr@2:         iSum += aWord & 0xffff;
williamr@2: }
williamr@2: 
williamr@2: // Add halfword in host byte order
williamr@2: inline void TChecksum::AddH(TUint16 aHalfWord)
williamr@2: {
williamr@2: 		__DEBUG_ONLY (const TInt one = 1;)
williamr@2: 		ASSERT(*(TUint8*)&one); //check that we are little-endian
williamr@2: 
williamr@2: 		iSum += ((aHalfWord << 8) | (aHalfWord >> 8)) & 0xffff;
williamr@2: }
williamr@2: 
williamr@2: // Add word in host byte order
williamr@2: inline void TChecksum::AddH(TUint32 aWord)
williamr@2: {
williamr@2: 		__DEBUG_ONLY (const TInt one = 1;)
williamr@2: 		ASSERT(*(TUint8*)&one); //check that we are little-endian
williamr@2: 
williamr@2:         iSum += (aWord >> 24);          // add octet  3
williamr@2:         iSum += (aWord >> 8) & 0xffff,  // add octets 2-1
williamr@2:         iSum += (aWord << 8) & 0xff00;  // add octet  0
williamr@2: }
williamr@2: 
williamr@2: // Fold 32-bit sum into 16 bits
williamr@2: inline void TChecksum::Fold()
williamr@2: {
williamr@2:         iSum = Fold(iSum);
williamr@2: }
williamr@2: 
williamr@2: // Return 16-bit inverted checksum
williamr@2: inline TUint32 TChecksum::Sum()
williamr@2: {
williamr@2:         return Fold(iSum) ^ 0xffff;
williamr@2: }
williamr@2: 
williamr@2: // Return 32-bit intermediate sum
williamr@2: inline TUint32 TChecksum::Sum32()
williamr@2: {
williamr@2:         return iSum;
williamr@2: }
williamr@2: 
williamr@2: // Reverse checksum direction. Can be used to back out partial sums.
williamr@2: inline void TChecksum::Reverse()
williamr@2: {
williamr@2:         iSum = Sum();
williamr@2: }
williamr@2: 
williamr@2: inline TUint32 TChecksum::Fold(TUint32 aSum)
williamr@2: {
williamr@2: 	aSum = (aSum >> 16) + (aSum & 0xffff);  // Max: 0x0001fffe
williamr@2: 	aSum += (aSum >> 16);                   // Max: 0x0001ffff
williamr@2:         return aSum & 0xffff;                   // Truncate to 16 bits
williamr@2: }
williamr@2: 
williamr@2: inline TUint16 TChecksum::ComplementedFold(TUint32 aSum)
williamr@2: {
williamr@2:         return (TUint16)~Fold(aSum);
williamr@2: }
williamr@2: 
williamr@2: template <class T>
williamr@2: void TInet6Checksum<T>::ComputeChecksum(RMBufChain &aPacket, const RMBufPktInfo *aInfo, TInt aOffset)
williamr@2: 	{
williamr@2:         TChecksum sum;
williamr@2: 	this->iHdr->SetChecksum(0);
williamr@2:         sum.Add(aPacket, aInfo, aOffset);
williamr@2: 	this->iHdr->SetChecksum(sum.Sum());
williamr@2: 	}
williamr@2: 
williamr@2: template <class T>
williamr@2: TBool TInet6Checksum<T>::VerifyChecksum(RMBufChain &aPacket, const RMBufPktInfo *aInfo, TInt aOffset)
williamr@2: 	{
williamr@2:         TChecksum sum;
williamr@2:         sum.Add(aPacket, aInfo, aOffset);
williamr@2:         return !sum.Sum();
williamr@2: 	}
williamr@2: //
williamr@2: // The following are mainly for the IPv4 Header checksum
williamr@2: //
williamr@2: template <class T>
williamr@2: void TInet6Checksum<T>::ComputeChecksum()
williamr@2: 	{
williamr@2:         TChecksum sum;
williamr@2: 	this->iHdr->SetChecksum(0);
williamr@2:         sum.Add((TUint16 *)(this->iHdr), this->iHdr->HeaderLength());
williamr@2: 	this->iHdr->SetChecksum(sum.Sum());
williamr@2: 	}
williamr@2: 
williamr@2: template <class T>
williamr@2: TBool TInet6Checksum<T>::VerifyChecksum()
williamr@2: 	{
williamr@2:         TChecksum sum;
williamr@2:         sum.Add((TUint16*)(this->iHdr), this->iHdr->HeaderLength());
williamr@2:         return !sum.Sum();
williamr@2: 	}
williamr@2: 
williamr@2: #endif