// 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 the License "Symbian Foundation License v1.0" to Symbian Foundation members and "Symbian Foundation End User License Agreement v1.0" to non-members

// which accompanies this distribution, and is available

// at the URL "http://www.symbianfoundation.org/legal/licencesv10.html".

//

// Initial Contributors:

// Nokia Corporation - initial contribution.

//

// Contributors:

//

// Description:

// ext_hdr.h - IPv6 extension headers

// Defines the basic classes for accessing the extension

// header structures within IPv6 packets.

// All return types codified as TInt (Native form and signed)

//

/**

 @file ext_hdr.h

 @ingroup ip_packet_formats

 @publishedAll

 @released

*/

#ifndef __EXT_HDR_H__

#define __EXT_HDR_H__

#include <e32def.h>

#include "in_hdr.h"

/**

* @addtogroup  ip_packet_formats

* @{

*/

/**

* @name Additional protocol numbers

*

* @{

*/

/** Hop-by-Hop Extension Header. See TInet6HeaderHopByHop. */

const TUint KProtocolInet6HopOptions = 0;

/** Tunneled IPv4. The next header is TInet6HeaderIP4. */

const TUint KProtocolInetIpip = 4;

/** Routing Header. See TInet6HeaderRouting. */

const TUint KProtocolInet6RoutingHeader = 43;

/** IPv6 Fragment Header. See TInet6HeaderFragment. */

const TUint KProtocolInet6Fragment = 44;

/** IPsec ESP header. See TInet6HeaderESP. */

const TUint KProtocolInetEsp	= 50;

/** IPsec AH header. See TInet6HeaderAH. */

const TUint KProtocolInetAh = 51;

/** No Next Header. */

const TUint KProtocolInet6NoNextHeader = 59;

/** Destination Options Extension Header. See TInet6Options. */

const TUint KProtocolInet6DestinationOptions = 60;

/* @} */

//

// TInet6HeaderExtension

// *********************

class TInet6HeaderExtension

	/**

	* Basic part of normal IPv6 extension headers.

	*

	* This is simple class to be used in scanning the extension headers

	* which are known to follow the following format:

	*

	* - 1st octet = Next Header field

	*

	* - 2nd octet = Length of the extension header (= (x+1)*8 octets)

	*

	* @note

	*	Extension headers do not need to follow this format. Unknown

	*	headers cannot be skipped over by just assuming this format!

	*

	* @publishedAll

	* @released

	*/

	{

public:

	inline static TInt MinHeaderLength() {return 8; }

	inline static TInt MaxHeaderLength() {return 8; }	

	inline TUint8* EndPtr() { return i + HeaderLength(); }

	inline TInt NextHeader() const { return i[0]; }

	inline TInt HdrExtLen() const { return i[1]; }	// Return raw value

	inline TInt HeaderLength() const { return (i[1]+1) << 3; } // Return true byte length

private:

	union

		{

		TUint8 i[8];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6HeaderHBH

	/**

	* IPv6 Hop-by-hop options header.

@verbatim

	From RFC 2460

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |  Next Header  |  Hdr Ext Len  |                               |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +

    |                                                               |

    .                                                               .

    .                            Options                            .

    .                                                               .

    |                                                               |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Next Header          8-bit selector.  Identifies the type of header

                        immediately following the Hop-by-Hop Options

                        header.  Uses the same values as the IPv4

                        Protocol field [RFC-1700 et seq.].

   Hdr Ext Len          8-bit unsigned integer.  Length of the Hop-by-

                        Hop Options header in 8-octet units, not

                        including the first 8 octets.

   Options              Variable-length field, of length such that the

                        complete Hop-by-Hop Options header is an integer

                        multiple of 8 octets long.  Contains one or more

                        TLV-encoded options, as described in section

                        4.2.

  And Options is:

	  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -

      |  Option Type  |  Opt Data Len |  Option Data

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -

      Option Type          8-bit identifier of the type of option.

      Opt Data Len         8-bit unsigned integer.  Length of the Option

                           Data field of this option, in octets.

      Option Data          Variable-length field.  Option-Type-specific

                           data.

@endverbatim

	* @publishedAll

	* @released

	*/

	{

public:

	inline TInt HeaderLength() const

		{

		return (i[1]+1) << 3;	// Return length in octets.

		}

	inline TUint8* EndPtr() { return i + HeaderLength(); }

	inline static TInt MinHeaderLength() {return 8; }	

	inline static TInt MaxHeaderLength() {return 8; }

	//

	// Access, Get Hop By Hop header values from the packet

	//

	inline TInt NextHeader() const

		{

		return i[0];

		}

	//From Options

	inline TInt OptionType() const

		/** @return The type of the first option */

		{

		return i[2];

		}

	inline TInt OptionDataLen() const

		/** @return The data length of the first option */

		{

		return i[3];

		}

	//

	// Access, SET Hop By Hop header values

	//

	inline void SetHdrExtLen(TInt aLength)

		{

		i[1]=(TUint8)aLength;

		}

	inline void SetNextHeader(TInt aNext)

		{

		i[0]=(TUint8)aNext;

		}

	//From Options

	inline void SetOptionType(TInt aType)

		/** Sets type of the first option.*/

		{

		i[2]=(TUint8)aType;

		}

	inline void SetOptionDataLen(TInt aLength)

		/** Sets data length of the first option.*/

		{

		i[3]=(TUint8)aLength;

		}

private:

	union

		{

		TUint8 i[8];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6HeaderHopByHop

	/**

	* IPv6 Hop-by-hop options header.

	* @publishedAll

	* @deprecated

	*	Because of the non-standard method naming and

	*	semantics. Use TInet6HeaderHBH instead.

	*/

	{

public:

	inline TInt HeaderLength() const

		{

		return i[1];

		}

	inline TUint8* EndPtr() { return i + HeaderLength() * 8 + MinHeaderLength(); }

	inline static TInt MinHeaderLength() {return 8; }	

	inline static TInt MaxHeaderLength() {return 8; }

	//

	// Access, Get Hop By Hop header values from the packet

	//

	inline TInt NextHeader() const

		/** @return The length in 8-byte units! (non-standard, should be bytes!) */

		{

		return i[0];

		}

	//From Options

	inline TInt OptionType() const

		/** @return The type of the first option */

		{

		return i[2];

		}

	inline TInt OptionDataLen() const

		/** @return The data length of the first option */

		{

		return i[3];

		}

	//

	// Access, SET Hop By Hop header values

	//

	inline void SetHeaderLength(TInt aLength)

		{

		i[1]=(TUint8)aLength;

		}

	inline void SetNextHeader(TInt aNext)

		{

		i[0]=(TUint8)aNext;

		}

	//From Options

	inline void SetOptionType(TInt aType)

		/** Sets type of the first option.*/

		{

		i[2]=(TUint8)aType;

		}

	inline void SetOptionDataLen(TInt aLength)

		/** Sets data length of the first option.*/

		{

		i[3]=(TUint8)aLength;

		}

private:

	union

		{

		TUint8 i[8];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6HeaderRouting

	/**

	* IPv6 Routing Header.

	* The Type 0 Routing header has the following format:

@verbatim

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |  Next Header  |  Hdr Ext Len  | Routing Type=0| Segments Left |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |                            Reserved                           |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |                                                               |

    +                                                               +

    |                                                               |

    +                           Address[1]                          +

    |                                                               |

    +                                                               +

    |                                                               |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |                                                               |

    +                                                               +

    |                                                               |

    +                           Address[2]                          +

    |                                                               |

    +                                                               +

    |                                                               |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    .                               .                               .

    .                               .                               .

    .                               .                               .

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

    |                                                               |

    +                                                               +

    |                                                               |

    +                           Address[n]                          +

    |                                                               |

    +                                                               +

    |                                                               |

    +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Next Header          8-bit selector.  Identifies the type of header

                        immediately following the Routing header.  Uses

                        the same values as the IPv4 Protocol field

                        [RFC-1700 et seq.].

   Hdr Ext Len          8-bit unsigned integer.  Length of the Routing

                        header in 8-octet units, not including the first

                        8 octets.  For the Type 0 Routing header, Hdr

                        Ext Len is equal to two times the number of

                        addresses in the header.

   Routing Type         0.

   Segments Left        8-bit unsigned integer.  Number of route

                        segments remaining, i.e., number of explicitly

                        listed intermediate nodes still to be visited

                        before reaching the final destination.

   Reserved             32-bit reserved field.  Initialized to zero for

                        transmission; ignored on reception.

   Address[1..n]        Vector of 128-bit addresses, numbered 1 to n.

@endverbatim

	* This header mapping describes only the fixed part, without

	* any addresses.

	* @publishedAll

	* @released

	*/

	{

public:

	inline static TInt MinHeaderLength() {return 8; }

	inline static TInt MaxHeaderLength() {return 8; }	

	inline TUint8* EndPtr() { return i + HeaderLength(); }

	enum TOffsets

		{

		O_NextHeader,

		O_HdrExtLen,

		O_RoutingType,

		O_SegmentsLeft,

		O_Address = 8

		};

	inline TInt NextHeader() const { return i[0]; }

	inline TInt HdrExtLen() const { return i[1]; }	// Return raw value

	inline TInt HeaderLength() const { return (i[1]+1) << 3; } // Return true byte length

	inline TInt RoutingType() const { return i[2]; }

	inline TInt SegmentsLeft() const { return i[3]; }

	//SET

	inline void SetNextHeader(TInt aNext) { i[0] = (TInt8)aNext; }

	inline void SetHdrExtLen(TInt aLen) { i[1] = (TUint8)aLen; }	

	inline void SetRoutingType(TInt aType) { i[2] = (TUint8)aType; }

	inline void SetSegmentsLeft(TInt aValue) { i[3] = (TUint8)aValue; }

private:

	union

		{

		TUint8 i[8];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6Options

	/**

	* IPv6 Option extension headers (Hop-by-Hop, Destination Options).

	*

@verbatim

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |  Next Header  |  Hdr Ext Len  |                               |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               +

   |                                                               |

   .                                                               .

   .                            Options                            .

   .                                                               .

   |                                                               |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

  Next Header          8-bit selector.  Identifies the type of header

                       immediately following the Destination Options

                       header.  Uses the same values as the IPv4

                       Protocol field [RFC-1700 et seq.].

  Hdr Ext Len          8-bit unsigned integer.  Length of the

                       Destination Options header in 8-octet units, not

                       including the first 8 octets.

  Options              Variable-length field, of length such that the

                       complete Destination Options header is an

                       integer multiple of 8 octets long.  Contains one

                       or  more TLV-encoded options, as described in

                       section 4.2.

@endverbatim

	* This mapping describes only the minimal 8 bytes.

	* @publishedAll

	* @released

	*/

	{

public:

	inline TInt HeaderLength() const { return (i[1]+1) << 3; } // Return true byte length

	inline static TInt MinHeaderLength() {return 8; }

	inline static TInt MaxHeaderLength() {return 8; }	

	inline TUint8* EndPtr() { return i + HeaderLength(); }

	enum TOffsets

		{

		O_NextHeader,

		O_HdrExtLen,

		O_Options

		};

	inline TInt NextHeader() const { return i[0]; }

	inline TInt HdrExtLen() const { return i[1]; }	// Return raw value

	inline void SetNextHeader(TInt aNext) { i[0] = (TInt8)aNext; }

	inline void SetHdrExtLen(TInt aLen) { i[1] = (TUint8)aLen; }

private:

	TUint8 i[8];

	};

/**

* @name Destination option types.

*

* @{

*/

/** One octet padding. */

const TUint8 KDstOptionPad1				= 0;

/** N octets padding */

const TUint8 KDstOptionPadN				= 1;

/** not used? (MIP6) */

const TUint8 KDstOptionBindingAck		= 7;

/** not used? (MIP6) */

const TUint8 KDstOptionBindingRequest	= 8;

/** not used? (MIP6) */

const TUint8 KDstOptionBindingUpdate	= 0xC6;

/** Home Address option (MIP6) */

const TUint8 KDstOptionHomeAddress		= 0xC9;

/** @} */

class TInet6OptionBase

	/**

	* IPv6 Option value header.

	*

	* A basic class for handling Type-Length-Value (TLV) options.

	*

@verbatim

	  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -

      |  Option Type  |  Opt Data Len |  Option Data

      +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+- - - - - - - - -

      Option Type          8-bit identifier of the type of option.

      Opt Data Len         8-bit unsigned integer.  Length of the Option

                           Data field of this option, in octets.

      Option Data          Variable-length field.  Option-Type-specific

                           data.

@endverbatim

	* Option values are used inside option headers (for example:

	* Hop-by-Hop options and Destination options).

	*

	* @publishedAll

	* @released

	*/

	{

public:

	inline static TInt MinHeaderLength()	{ return 2; }

	inline static TInt MaxHeaderLength()	{ return 2; }

	inline TInt Type() const				{ return i[0]; }

	inline TInt HeaderLength() const { return i[1] + 2; }

	inline void SetType(TInt aType)			{ i[0] = (TUint8)aType; }

	inline void SetDataLen(TInt aLen)		{ i[1] = (TUint8)aLen; }

	inline TUint8* EndPtr() { return i + HeaderLength(); }

private:

	TUint8	i[2];

	};

class TInet6DstOptionBase

	/**

	* IPv6 Option value header.

	* @publishedAll

	* @deprecated

	*	Because of the non-standard method naming and

	*	semantics. Use TInet6OptionBase instead.

	*/

	{

public:

	inline static TInt MinHeaderLength()	{ return 2; }

	inline static TInt MaxHeaderLength()	{ return 2; }

	inline TInt Type() const				{ return i[0]; }

	inline TInt HeaderLength() const { return i[1]; }

	inline void SetType(TInt aType)			{ i[0] = (TUint8)aType; }

	inline void SetHeaderLength(TInt aLen)	{ i[1] = (TUint8)aLen; }

	inline TUint8* EndPtr() { return i + 2 + HeaderLength(); }

private:

	TUint8	i[2];

	};

class TInet6HeaderFragment

	/**

	* IPv6 Fragment Header.

@verbatim

RFC2460

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |  Next Header  |   Reserved    |      Fragment Offset    |Res|M|

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                         Identification                        |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   Next Header          8-bit selector.  Identifies the initial header

                        type of the Fragmentable Part of the original

                        packet (defined below).  Uses the same values as

                        the IPv4 Protocol field [RFC-1700 et seq.].

   Reserved             8-bit reserved field.  Initialized to zero for

                        transmission; ignored on reception.

   Fragment Offset      13-bit unsigned integer.  The offset, in 8-octet

                        units, of the data following this header,

                        relative to the start of the Fragmentable Part

                        of the original packet.

   Res                  2-bit reserved field.  Initialized to zero for

                        transmission; ignored on reception.

   M flag               1 = more fragments; 0 = last fragment.

   Identification       32 bits.  See description below.

@endverbatim

	* @publishedAll

	* @released

	*/

	{

public:

	enum TOffsets

		{

		O_FragmentOffset = 2

		};

	inline TInt HeaderLength() const

		{

		return 8;

		}

	inline TUint8* EndPtr() { return i + HeaderLength(); }

	inline static TInt MinHeaderLength() {return 8; }

	inline static TInt MaxHeaderLength() {return 8; }

	//

	// Access, Get Fragmentation header values from the packet

	//

	inline TInt NextHeader() const { return i[0]; }

	inline TInt FragmentOffset() const

		{

		//

		//	The Offset is returned as octet count (3 righmost bits are zero)

		//

		return ((i[2] << 8) + i[3]) & 0xfff8;

		}

	inline TInt MFlag() const

		{

		return i[3] & 0x01;

		}

	inline TInt32 Id() const

		{

		return *(TInt32 *)(&i[4]);	// *ASSUMES* proper aligment!!!

		}

	//

	// Building methods

	//

	inline void ZeroAll()

		{

		*((TInt32 *)&i[0]) = 0;		// *ASSUMES* proper aligment!!!

		*((TInt32 *)&i[4]) = 0;		// *ASSUMES* proper aligment!!!

		}

	inline void SetNextHeader(TInt aNext)

		{

		i[0] = (TUint8)aNext;

		}

	inline void SetFragmentOffset(TInt aOffset)

		{

		//

		// The aOffset is assumed to be given in octets. The least significant

		// 3 bits should be ZERO (bits are just masked away).

		//

		i[2]=(TUint8)(aOffset >> 8);

		i[3]=(TUint8)((i[3] & 0x7) | (aOffset & ~0x7));

		}

	inline void SetMFlag(TInt aFlag)

		{

		i[3]= (TUint8)((i[3] & ~0x1) | (aFlag & 0x1));

		}

	inline void SetId(TInt32 aId)

		{

		*((TInt32 *)&i[4]) = aId;	// *ASSUMES* proper aligment!!!

		}

private:

	union

		{

		TUint8 i[8];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6HeaderAH

	/**

	* IPsec Authentication Header.

	*

	* The function parameters and return values are in host order,

	* except SPI, which is always in network byte order.

@verbatim

Extract from RFC-2402

    0                   1                   2                   3

    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   | Next Header   |  Payload Len  |          RESERVED             |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                 Security Parameters Index (SPI)               |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                    Sequence Number Field                      |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

   |                                                               |

   +                Authentication Data (variable)                 |

   |                                                               |

   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

@endverbatim

	* @publishedAll

	* @released

	*/

	{

public:

	//

	// Basic

	//

	inline static TInt MinHeaderLength() {return 3*4; }

	inline static TInt MaxHeaderLength() {return 3*4; }

	inline TUint8 *EndPtr() {return i + HeaderLength();}

	//

	// Access, get values

	//

	inline TInt NextHeader() const

		{

		return i[0];

		}

	//

	// PayloadLength returns the raw value

	//

	inline TInt PayloadLength() const

		{

		return i[1];

		}

	//

	// *NOTE* AH is called IPv6 extension header, but its

	// length field semantics does not follow the normal

	// IPv6 extension header logic (it follows the IPv4)

	//

	inline TInt HeaderLength() const

		{

		return (i[1]+2) << 2;	// IPv4 and IPv6

		}

	//

	// SPI is returned in network byte order

	//

	inline TUint32 SPI() const

		{

		return *((TUint32 *)(i + 4));

		}

	inline TUint32 Sequence() const

		{

		return (i[8] << 24) | (i[9] << 16) | (i[10] << 8) | i[11];

		}

	// The length of the Authentication Data (in octets).

	// *NOTE* This will include the potential padding! -- msa

	inline TInt DataLength() const		{

		return HeaderLength() - 12;

		}

	inline TPtr8 ICV()

		{

		return TPtr8((TUint8 *)&i[12], DataLength(), DataLength());

		}

	//

	// Build

	//

	inline void SetNextHeader(TInt aNext)

		{

		i[0] = (TUint8)aNext;

		}

	inline void SetPayloadLength(TInt aByte)

		{

		i[1] = (TUint8)aByte;

		}

	//

	// *NOTE* AH is called IPv6 extension header, but its

	// length field semantics does not follow the normal

	// IPv6 extension header logic (it follows the IPv4)

	// As this is bit tricky, a "cooked version" of PayloadLength

	// setting is also provided (e.g. take in bytes, and compute

	// the real payload length value) -- msa

	inline void SetHeaderLength(TInt aLength)

		{

		i[1] = (TUint8)((aLength >> 2) - 2);

		}

	inline void SetSPI(TUint32 aSPI)

		{

		*((TUint32 *)(i + 4)) = aSPI;

		}

	inline void SetReserved(TInt aValue)

		{

		i[3] = (TUint8)aValue;

		i[2] = (TUint8)(aValue >> 8);

		}

	inline void SetSequence(TUint32 aSeq)

		{

		i[11] = (TUint8)aSeq;

		i[10] = (TUint8)(aSeq >> 8);

		i[9] = (TUint8)(aSeq >> 16);

		i[8] = (TUint8)(aSeq >> 24);

		}

protected:

	union

		{

		TUint8 i[3*4];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

class TInet6HeaderESP

	/**

	* IPsec Encapsulating Security Payload Packet Format.

	*

	* The function parameters and return values are in host

	* order (except SPI, which is always in network byte order)

	*

@verbatim

RFC-2406

 0                   1                   2                   3

 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ----

|               Security Parameters Index (SPI)                 | ^Auth.

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Cov-

|                      Sequence Number                          | |erage

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | ----

|                    Payload Data* (variable)                   | |   ^

~                                                               ~ |   |

|                                                               | |Conf.

+               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |Cov-

|               |     Padding (0-255 bytes)                     | |erage*

+-+-+-+-+-+-+-+-+               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |   |

|                               |  Pad Length   | Next Header   | v   v

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ ------

|                 Authentication Data (variable)                |

~                                                               ~

|                                                               |

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

@endverbatim

	* This only defines the fixed portion of the ESP, 8 bytes).

	* @publishedAll

	* @released

	*/

	{

public:

	//

	// Basic

	//

	inline static TInt MinHeaderLength() {return 2*4; }

	inline static TInt MaxHeaderLength() {return 2*4; }

	inline TInt HeaderLength() const {return 2*4; }

	inline TUint8 *EndPtr() {return i + HeaderLength();}

	//

	// Access, get values

	//

	//

	// SPI is returned in network byte order

	//

	inline TUint32 SPI() const

		{

		return *((TUint32 *)(i + 0));

		}

	inline TUint32 Sequence() const

		{

		return (i[4] << 24) | (i[5] << 16) | (i[6] << 8) | i[7];

		}

	//

	// IV is not exactly part of the header, but provide

	// a method that returns a Ptr to it (assuming the

	// IV is accessible directly after the fixed part).

	//

	inline TPtr8 IV(TInt aLen)

		{

		return TPtr8((TUint8 *)&i[sizeof(i)], aLen, aLen);

		}

	//

	// Build

	//

	inline void SetSPI(TUint32 aSPI)

		{

		*((TUint32 *)(i + 0)) = aSPI;

		}

	inline void SetSequence(TUint32 aSeq)

		{

		i[7] = (TUint8)aSeq;

		i[6] = (TUint8)(aSeq >> 8);

		i[5] = (TUint8)(aSeq >> 16);

		i[4] = (TUint8)(aSeq >> 24);

		}

protected:

	union

		{

		TUint8 i[2*4];

		TUint32 iAlign;	// A dummy member to force the 4 byte alignment

		};

	};

/** @} */

#endif