/* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */

/*

 * Copyright (c) 2010 Dean Armstrong

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License version 2 as

 * published by the Free Software Foundation;

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, write to the Free Software

 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

 *

 * Authors: Dean Armstrong <deanarm@gmail.com>

 */

#ifndef WIFI_INFORMATION_ELEMENT_H

#define WIFI_INFORMATION_ELEMENT_H

#include "ns3/header.h"

#include "ns3/simple-ref-count.h"

namespace ns3 {

/**

 * This type is used to represent an Information Element ID. An

 * enumeration would be tidier, but doesn't provide for the

 * inheritance that is currently preferable to cleanly support

 * pre-standard modules such as mesh. Maybe there is a nice way of

 * doing this with a class.

 *

 * Until such time as a better way of implementing this is dreamt up

 * and applied, developers will need to be careful to avoid

 * duplication of IE IDs in the defines below (and in files which

 * declare "subclasses" of WifiInformationElement). Sorry.

 */

typedef uint8_t WifiInformationElementId;

/**

 * Here we have definition of all Information Element IDs in IEEE

 * 802.11-2007. See the comments for WifiInformationElementId - this could

 * probably be done in a considerably tidier manner.

 */

#define IE_SSID                                ((WifiInformationElementId)0)

#define IE_SUPPORTED_RATES                     ((WifiInformationElementId)1)

#define IE_FH_PARAMETER_SET                    ((WifiInformationElementId)2)

#define IE_DS_PARAMETER_SET                    ((WifiInformationElementId)3)

#define IE_CF_PARAMETER_SET                    ((WifiInformationElementId)4)

#define IE_TIM                                 ((WifiInformationElementId)5)

#define IE_IBSS_PARAMETER_SET                  ((WifiInformationElementId)6)

#define IE_COUNTRY                             ((WifiInformationElementId)7)

#define IE_HOPPING_PATTERN_PARAMETERS          ((WifiInformationElementId)8)

#define IE_HOPPING_PATTERN_TABLE               ((WifiInformationElementId)9)

#define IE_REQUEST                             ((WifiInformationElementId)10)

#define IE_BSS_LOAD                            ((WifiInformationElementId)11)

#define IE_EDCA_PARAMETER_SET                  ((WifiInformationElementId)12)

#define IE_TSPEC                               ((WifiInformationElementId)13)

#define IE_TCLAS                               ((WifiInformationElementId)14)

#define IE_SCHEDULE                            ((WifiInformationElementId)15)

#define IE_CHALLENGE_TEXT                      ((WifiInformationElementId)16)

// 17 to 31 are reserved in 802.11-2007

#define IE_POWER_CONSTRAINT                    ((WifiInformationElementId)32)

#define IE_POWER_CAPABILITY                    ((WifiInformationElementId)33)

#define IE_TPC_REQUEST                         ((WifiInformationElementId)34)

#define IE_TPC_REPORT                          ((WifiInformationElementId)35)

#define IE_SUPPORTED_CHANNELS                  ((WifiInformationElementId)36)

#define IE_CHANNEL_SWITCH_ANNOUNCEMENT         ((WifiInformationElementId)37)

#define IE_MEASUREMENT_REQUEST                 ((WifiInformationElementId)38)

#define IE_MEASUREMENT_REPORT                  ((WifiInformationElementId)39)

#define IE_QUIET                               ((WifiInformationElementId)40)

#define IE_IBSS_DFS                            ((WifiInformationElementId)41)

#define IE_ERP_INFORMATION                     ((WifiInformationElementId)42)

#define IE_TS_DELAY                            ((WifiInformationElementId)43)

#define IE_TCLAS_PROCESSING                    ((WifiInformationElementId)44)

#define IE_QOS_CAPABILITY                      ((WifiInformationElementId)46)

// 47 is reserved in 802.11-2007

#define IE_RSN                                 ((WifiInformationElementId)48)

// 49 is reserved in 802.11-2007

#define IE_EXTENDED_SUPPORTED_RATES            ((WifiInformationElementId)50)

// 51 to 126 are reserved in 802.11-2007

#define IE_EXTENDED_CAPABILITIES               ((WifiInformationElementId)127)

// 128 to 220 are reserved in 802.11-2007

#define IE_VENDOR_SPECIFIC                     ((WifiInformationElementId)221)

// 222 to 255 are reserved in 802.11-2007

/**

 * \brief Information element, as defined in 802.11-2007 standard

 * \ingroup wifi

 *

 * The IEEE 802.11 standard includes the notion of Information

 * Elements, which are encodings of management information to be

 * communicated between STAs in the payload of various frames of type

 * Management. Information Elements (IEs) have a common format, each

 * starting with a single octet - the Element ID, which indicates the

 * specific type of IE (a type to represent the options here is

 * defined as WifiInformationElementId). The next octet is a length field and

 * encodes the number of octets in the third and final field, which is

 * the IE Information field.

 *

 * The class ns3::WifiInformationElement provides a base for classes

 * which represent specific Information Elements. This class defines

 * pure virtual methods for serialisation

 * (ns3::WifiInformationElement::SerializeInformationField) and

 * deserialisation

 * (ns3::WifiInformationElement::DeserializeInformationField) of IEs, from

 * or to data members or other objects that simulation objects use to

 * maintain the relevant state.

 *

 * This class also provides an implementation of the equality

 * operator, which operates by comparing the serialised versions of

 * the two WifiInformationElement objects concerned.

 *

 * Elements are defined to have a common general format consisting of

 * a 1 octet Element ID field, a 1 octet length field, and a

 * variable-length element-specific information field. Each element is

 * assigned a unique Element ID as defined in this standard. The

 * Length field specifies the number of octets in the Information

 * field.

 *

 * This class is pure virtual and acts as base for classes which know

 * how to serialize specific IEs.

 */

class WifiInformationElement : public SimpleRefCount<WifiInformationElement>

{

public:

  virtual ~WifiInformationElement ();

  /// Serialize entire IE including Element ID and length fields

  Buffer::Iterator Serialize (Buffer::Iterator i) const;

  /// Deserialize entire IE, which must be present. The iterator

  /// passed in must be pointing at the Element ID (i.e., the very

  /// first octet) of the correct type of information element,

  /// otherwise this method will generate a fatal error.

  Buffer::Iterator Deserialize (Buffer::Iterator i);

  /// Deserialize entire IE if it is present. The iterator passed in

  /// must be pointing at the Element ID of an information element. If

  /// the Element ID is not the one that the given class is interested

  /// in then it will return the same iterator.

  Buffer::Iterator DeserializeIfPresent (Buffer::Iterator i);

  /// Get the size of the serialized IE including Element ID and

  /// length fields.

  uint16_t GetSerializedSize () const;

  ///\name Each subclass must implement

  //\{

  /// Own unique Element ID

  virtual WifiInformationElementId ElementId () const = 0;

  /// Length of serialized information (i.e., the length of the body

  /// of the IE, not including the Element ID and length octets. This

  /// is the value that will appear in the second octet of the entire

  /// IE - the length field)

  virtual uint8_t GetInformationFieldSize () const = 0;

  /// Serialize information (i.e., the body of the IE, not including

  /// the Element ID and length octets)

  virtual void SerializeInformationField (Buffer::Iterator start) const = 0;

  /// Deserialize information (i.e., the body of the IE, not including

  /// the Element ID and length octets)

  virtual uint8_t DeserializeInformationField (Buffer::Iterator start,

                                               uint8_t length) = 0;

  //\}

  /// In addition, a subclass may optionally override the following...

  //\{

  /// Generate human-readable form of IE

  virtual void Print (std::ostream &os) const;

  /// Compare information elements using Element ID

  virtual bool operator< (WifiInformationElement const & a) const;

  /// Compare two IEs for equality by ID & Length, and then through

  /// memcmp of serialised version

  virtual bool operator== (WifiInformationElement const & a) const;

  //\}

};

}

#endif /* WIFI_INFORMATION_ELEMENT_H */