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@2: // under the terms of the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members
williamr@2: // which accompanies this distribution, and is available
williamr@2: // at the URL "http://www.symbianfoundation.org/legal/licencesv10.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: // ip6_hdr.h - IPv6 header structure
williamr@2: // This module defines the basic classes for accessing the header
williamr@2: // structures within IPv6 packets.
williamr@2: // Defines the IPv6 header structure.
williamr@2: //
williamr@2: 
williamr@2: 
williamr@2: 
williamr@2: /**
williamr@2:  @file ip6_hdr.h
williamr@2:  @ingroup ip_packet_formats
williamr@2:  @publishedAll
williamr@2:  @released
williamr@2: */
williamr@2: 
williamr@2: #ifndef __IP6_HDR_H__
williamr@2: #define __IP6_HDR_H__
williamr@2: 
williamr@2: #include "in_hdr.h"
williamr@2: #include <in_sock.h> // Only for TIp6Addr !
williamr@2: 
williamr@2: /**
williamr@2: * @defgroup  ip_packet_formats	IPv4 and IPv6 packet formats and constants
williamr@2: *
williamr@2: * These headers define various constants and special <em>mapping or overlay
williamr@2: * classes</em> to be used in accessing and building the IP packets. The
williamr@2: * mapping classes are not intended to be used in declaring
williamr@2: * variables (although some of them do support that use also).
williamr@2: *
williamr@2: * The normal usage is to typecast a binary buffer
williamr@2: * to a mapping class. For example
williamr@2: * assuming a buf contains a raw IPv6 packet:
williamr@2: *
williamr@2: @code
williamr@2: 	TBuf8<2000> buf;
williamr@2: 
williamr@2: 	TInet6HeaderIP &ip = *(TInet6HeaderIP *)buf.Ptr();
williamr@2: 	if (ip.MinHeaderLength() > buf.Length() ||
williamr@2: 		ip.HeaderLength() + ip.PayloadLength() > buf.Length())
williamr@2: 		{
williamr@2: 		// Oops. packet too short!
williamr@2: 		}
williamr@2: 	else if (ip.Version() == 6)
williamr@2: 		{
williamr@2: 		// Packet seems to be IPv6 packet.
williamr@2: 		}
williamr@2: @endcode
williamr@2: *
williamr@2: * Within the TCP/IP stack, the packets are stored in RMBufChain objects.
williamr@2: * The data is not in a contiguous memory area and accessing the headers is
williamr@2: * more complicated. For that purpose there is a template class TInet6Packet,
williamr@2: * which can use any <em>mapping class</em> as a template parameter and
williamr@2: * provides functions to access the header within the chain. Assuming the
williamr@2: * a RMBufChain object buf contains the packet, equivalent code would be:
williamr@2: *
williamr@2: @code
williamr@2: 	RMBufChain buf;
williamr@2: 
williamr@2: 	TInet6Packet<TInet6HeaderIP> ip(buf);
williamr@2: 	if (ip.iHdr == NULL ||
williamr@2: 		ip.iHdr->HeaderLength() + ip.iHdr->PayloadLength() > buf.Length())
williamr@2: 		{
williamr@2: 		// Opps. packet too short!
williamr@2: 		}
williamr@2: 	else if (ip.iHdr->Version() == 6)
williamr@2: 		{
williamr@2: 		// Packet seems to be IPv6 packet.
williamr@2: 		}
williamr@2: @endcode
williamr@2: * The TInet6Packet template does automatic MinHeaderLength check. The iHdr
williamr@2: * member variable is set only if the mapping succeeds at least for MinHeaderLength
williamr@2: * octets.
williamr@2: *
williamr@2: * All mapping headers must have the following functions defined:
williamr@2: *
williamr@2: * - static function MinHeaderLength returns the minimum header length in octets.
williamr@2: *
williamr@2: * - static function MaxHeaderLength returns the maximum header length in octets (not used much).
williamr@2: *
williamr@2: * - HeaderLength returns the actual length of a header instance in octets.
williamr@2: *	Note that this may return garbage value, if the mapped header is invalid.
williamr@2: *	The return value can be larger than indicated by MinHeaderLength, and
williamr@2: *	as the mapping is only guaranteed up to that size, user must separately
williamr@2: *	verify the accessibility of a full header in such case. 
williamr@2: * @{
williamr@2: * @}
williamr@2: */
williamr@2: 
williamr@2: /**
williamr@2: * @addtogroup  ip_packet_formats
williamr@2: * @{
williamr@2: */
williamr@2: 
williamr@2: /**
williamr@2: * The IPv6 minimum value for Maximum Transmission Unit (MTU) as defined in RFC 2460. 
williamr@2: * 
williamr@2: * @since v7.0
williamr@2: */
williamr@2: const TInt KInet6MinMtu = 1280;
williamr@2: 
williamr@2: //
williamr@2: // TInet6HeaderIP
williamr@2: // **************
williamr@2: //	Methods of manipulating IPv6 IP header.
williamr@2: //
williamr@2: //	This implementation assumes TUint8 is exactly 8 bits (and not
williamr@2: //	9 or more)
williamr@2: class TInet6HeaderIP
williamr@2: /**
williamr@2: * Encapsulates an IPv6 IP header. 
williamr@2: * @verbatim
williamr@2:  *************************
williamr@2:  Extract from the RFC-2460
williamr@2:  *************************
williamr@2: 
williamr@2:    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
williamr@2:    |Version| Traffic Class |           Flow Label                  |
williamr@2:    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
williamr@2:    |         Payload Length        |  Next Header  |   Hop Limit   |
williamr@2:    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
williamr@2:    |                                                               |
williamr@2:    +                                                               +
williamr@2:    |                                                               |
williamr@2:    +                         Source Address                        +
williamr@2:    |                                                               |
williamr@2:    +                                                               +
williamr@2:    |                                                               |
williamr@2:    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
williamr@2:    |                                                               |
williamr@2:    +                                                               +
williamr@2:    |                                                               |
williamr@2:    +                      Destination Address                      +
williamr@2:    |                                                               |
williamr@2:    +                                                               +
williamr@2:    |                                                               |
williamr@2:    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
williamr@2: 
williamr@2:    Version              4-bit Internet Protocol version number = 6.
williamr@2: 
williamr@2:    Traffic Class        8-bit traffic class field.  See section 7.
williamr@2: 
williamr@2:    Flow Label           20-bit flow label.  See section 6.
williamr@2: 
williamr@2:    Payload Length       16-bit unsigned integer.  Length of the IPv6
williamr@2:                         payload, i.e., the rest of the packet following
williamr@2:                         this IPv6 header, in octets.  (Note that any
williamr@2:                         extension headers [section 4] present are
williamr@2:                         considered part of the payload, i.e., included
williamr@2:                         in the length count.)
williamr@2: 
williamr@2:    Next Header          8-bit selector.  Identifies the type of header
williamr@2:                         immediately following the IPv6 header.  Uses the
williamr@2:                         same values as the IPv4 Protocol field [RFC-1700
williamr@2:                         et seq.].
williamr@2: 
williamr@2:    Hop Limit            8-bit unsigned integer.  Decremented by 1 by
williamr@2:                         each node that forwards the packet. The packet
williamr@2:                         is discarded if Hop Limit is decremented to
williamr@2:                         zero.
williamr@2: 
williamr@2:    Source Address       128-bit address of the originator of the packet.
williamr@2: 
williamr@2:    Destination Address  128-bit address of the intended recipient of the
williamr@2:                         packet (possibly not the ultimate recipient, if
williamr@2:                         a Routing header is present)
williamr@2: @endverbatim
williamr@2: * @publishedAll
williamr@2: * @released
williamr@2: * @since v7.0
williamr@2: */
williamr@2: 	{
williamr@2: public:
williamr@2: 	enum TOffsets
williamr@2: 		{
williamr@2: 		O_PayloadLength = 4,
williamr@2: 		O_NextHeader = 6,
williamr@2: 		O_HopLimit = 7,
williamr@2: 		O_SrcAddr = 8,
williamr@2: 		O_DstAddr = 24
williamr@2: 		};
williamr@2: 
williamr@2: 	// Basic functions, common to all header classes
williamr@2: 	// *********************************************
williamr@2: 
williamr@2: 	/**
williamr@2: 	* Gets the header length.	
williamr@2: 	* 
williamr@2: 	* Note that the header length is fixed.
williamr@2: 	* 
williamr@2: 	* @return	Header length.
williamr@2: 	*/
williamr@2: 	inline TInt HeaderLength() const {return 40;}
williamr@2: 	/**
williamr@2: 	* Gets the minimum header length.
williamr@2: 	* 
williamr@2: 	* Note that the header length is fixed.
williamr@2: 	* 
williamr@2: 	* @return	Minimum header length
williamr@2: 	*/
williamr@2: 	inline static TInt MinHeaderLength() {return 40; }
williamr@2: 	/**
williamr@2: 	* Gets the maximum header length.
williamr@2: 	* 
williamr@2: 	* Note that the header length is fixed.
williamr@2: 	* 
williamr@2: 	* @return	Maximum header length
williamr@2: 	*/
williamr@2: 	inline static TInt MaxHeaderLength() {return 40; }
williamr@2: 	/**
williamr@2: 	* Gets a pointer to the byte following the header.
williamr@2: 	* 
williamr@2: 	* @return	Pointer to the byte following the header
williamr@2: 	*/
williamr@2: 	inline TUint8 *EndPtr() {return i + HeaderLength();}
williamr@2: 
williamr@2: 	// IPv6 specific methods, get IP header field values from the packet
williamr@2: 	// *****************************************************************
williamr@2: 
williamr@2: 	inline TInt Version() const
williamr@2: 		/**
williamr@2: 		* Gets the IP version from the header.
williamr@2: 		*
williamr@2: 		* @return	IP version
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return (i[0] >> 4) & 0xf;
williamr@2: 		}
williamr@2: 	inline TInt TrafficClass() const
williamr@2: 		/**
williamr@2: 		* Gets the traffic class from the header.
williamr@2: 		*
williamr@2: 		* @return	Traffic class
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return ((i[0] << 4) & 0xf0) | ((i[1] >> 4) & 0x0f);
williamr@2: 		}
williamr@2: 	inline TInt FlowLabel() const
williamr@2: 		/**
williamr@2: 		* Gets the flow label from the header.
williamr@2: 		* 
williamr@2: 		* @return	Flow label (host byte order)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return ((i[1] << 16) | (i[2] << 8) | i[3]) & 0xfffff;
williamr@2: 		// Could also use any deterministic permutation of the 20 bits,
williamr@2: 		// if Flow label can be treated as opaque 20 bits, and not as
williamr@2: 		// integer where host/net byte order comes into play --msa
williamr@2: 		}
williamr@2: 	inline TInt PayloadLength() const
williamr@2: 		/**
williamr@2: 		* Gets the payload length from the header.
williamr@2: 		*
williamr@2: 		* @return	Payload length
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return (i[4] << 8) | i[5];
williamr@2: 		}
williamr@2: 	inline TInt NextHeader() const
williamr@2: 		/**
williamr@2: 		* Gets the next header selector from the header.
williamr@2: 		*
williamr@2: 		* @return	Next header selector (0..255)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return i[6];
williamr@2: 		}
williamr@2: 	inline TInt HopLimit() const
williamr@2: 		{
williamr@2: 		/**
williamr@2: 		* Gets the hop limit from the header.
williamr@2: 		*
williamr@2: 		* @return	Hop limit (0..255)
williamr@2: 		*/
williamr@2: 		return i[7];
williamr@2: 		}
williamr@2: 	//
williamr@2: 	// The following return a modifiable reference, so
williamr@2: 	// they can be used both for access and build.
williamr@2: 	//
williamr@2: 	inline TIp6Addr &SrcAddr() const
williamr@2: 		/**
williamr@2: 		* Gets the source address from the header.
williamr@2: 		*
williamr@2: 		* @return	Source address
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return (TIp6Addr &)i[8];
williamr@2: 		}
williamr@2: 	inline TIp6Addr &DstAddr() const
williamr@2: 		/**
williamr@2: 		* Gets the destination address from the header.
williamr@2: 		*
williamr@2: 		* @return	Destination address
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return (TIp6Addr &)i[24];
williamr@2: 		}
williamr@2: 
williamr@2: 	inline TBool EcnIsCongestion()
williamr@2: 		/**
williamr@2: 		* Gets ECN congestion status.
williamr@2: 		*
williamr@2: 		* see RFC-3168 for details.
williamr@2: 		*
williamr@2: 		* @return	True, if CE bit is set on an ECN capable packet.
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		return ((TrafficClass() & 3) == 3);
williamr@2: 		}
williamr@2: 
williamr@2: 
williamr@2: 	// IPv6 specific methods, set IP header field values into the packet
williamr@2: 	// *****************************************************************
williamr@2: 
williamr@2: 	inline void Init()
williamr@2: 		/**
williamr@2: 		* Initialises the header to basic initial values.
williamr@2: 		*
williamr@2: 		* @li Version = 6
williamr@2: 		* @li Traffic Class = 0
williamr@2: 		* @li Flow Label = 0
williamr@2: 		* @li Payload Length = 0
williamr@2: 		* @li Next Header = 0
williamr@2: 		* @li Hop Limit = 0
williamr@2: 		*
williamr@2: 		* The Source and Destination address fields are not touched.
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		static const union { TUint8 a[4]; TUint32 b;} x = { {6 << 4, 0, 0, 0} };
williamr@2: 		(TUint32 &)i[0] = x.b;
williamr@2: 		(TUint32 &)i[4] = 0;
williamr@2: 		}
williamr@2: 
williamr@2: 
williamr@2: 	inline void SetVersion(TInt aVersion)
williamr@2: 		/**
williamr@2: 		* Sets the IP version in the header.
williamr@2: 		*
williamr@2: 		* @param aVersion	IP version (0..15, = 6 for IPv6)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[0] = (TUint8)((i[0] & 0x0f) | ((aVersion << 4) & 0xf0));
williamr@2: 		}
williamr@2: 	inline void SetTrafficClass(TInt aClass)
williamr@2: 		/**
williamr@2: 		* Sets the traffic class in the header.
williamr@2: 		* 
williamr@2: 		* @param aClass	Traffic class (0..255)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[0] = (TUint8)((i[0] & 0xf0) | (aClass >> 4) & 0x0f);
williamr@2: 		i[1] = (TUint8)((i[1] & 0x0f) | (aClass << 4) & 0xf0);
williamr@2: 		}
williamr@2: 	inline void SetFlowLabel(TInt aFlow)
williamr@2: 		/**
williamr@2: 		* Sets the flow label in the header.
williamr@2: 		* 
williamr@2: 		* @param aFlow	Flow label (20 bit integer in host order)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[1] = (TUint8)((i[1] & 0xf0) | ((aFlow >> 16) & 0x0f));
williamr@2: 		i[2] = (TUint8)(aFlow >> 8);
williamr@2: 		i[3] = (TUint8)aFlow;
williamr@2: 		}
williamr@2: 
williamr@2: 	inline void SetPayloadLength(TInt aLength)
williamr@2: 		/**
williamr@2: 		* Sets the payload length in the header.
williamr@2: 		* 
williamr@2: 		* @param aLength	Payload length
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[4] = (TUint8)(aLength >> 8);
williamr@2: 		i[5] = (TUint8)aLength;
williamr@2: 		}
williamr@2: 
williamr@2: 	inline void SetNextHeader(TInt aNextHeader)
williamr@2: 		/**
williamr@2: 		* Sets the next header selector from the header.
williamr@2: 		*
williamr@2: 		* @param aNextHeader	Next header selector (0..255)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[6] = (TUint8)aNextHeader;
williamr@2: 		}
williamr@2: 	inline void SetHopLimit(TInt aLimit)
williamr@2: 		/**
williamr@2: 		* Sets the hop limit in the header.
williamr@2: 		*
williamr@2: 		* @param aLimit	Hop limit (0..255)
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		i[7] = (TUint8)aLimit;
williamr@2: 		}
williamr@2: 	inline void SetSrcAddr(const TIp6Addr &anAddr)
williamr@2: 		/**
williamr@2: 		* Sets the source address in the header.
williamr@2: 		* 
williamr@2: 		* @param anAddr	Source address
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		(TIp6Addr &)i[8] = anAddr;
williamr@2: 		}
williamr@2: 	inline void SetDstAddr(const TIp6Addr &anAddr)
williamr@2: 		/**
williamr@2: 		* Sets the destination address in the header.
williamr@2: 		* 
williamr@2: 		* @param anAddr	Destination address
williamr@2: 		*/
williamr@2: 		{
williamr@2: 		(TIp6Addr &)i[24] = anAddr;
williamr@2: 		}
williamr@2: 							
williamr@2: private:
williamr@2: 	union
williamr@2: 		{
williamr@2: 		TUint8 i[40];
williamr@2: 		TUint32 iAlign;	// A dummy member to force the 4 byte alignment
williamr@2: 		};
williamr@2: 	};
williamr@2: 
williamr@2: /** @} */
williamr@2: #endif