1 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */ 2 /* 3 * Copyright (c) 2007 Emmanuelle Laprise 4 * 5 * This program is free software; you can redistribute it and/or modify 6 * it under the terms of the GNU General Public License version 2 as 7 * published by the Free Software Foundation; 8 * 9 * This program is distributed in the hope that it will be useful, 10 * but WITHOUT ANY WARRANTY; without even the implied warranty of 11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 12 * GNU General Public License for more details. 13 * 14 * You should have received a copy of the GNU General Public License 15 * along with this program; if not, write to the Free Software 16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 17 * 18 * Author: Emmanuelle Laprise <emmanuelle.laprise@bluekazoo.ca> 19 */ 20 21 #ifndef ETHERNET_TRAILER_H 22 #define ETHERNET_TRAILER_H 23 24 #include "ns3/trailer.h" 25 #include "ns3/packet.h" 26 #include <string> 27 28 namespace ns3 { 29 30 31 /** 32 * \ingroup network 33 * 34 * \brief Packet trailer for Ethernet 35 * 36 * This class can be used to add and verify the FCS at the end of an 37 * Ethernet packet. 38 */ 39 class EthernetTrailer : public Trailer 40 { 41 public: 42 /** 43 * \brief Construct a null ethernet trailer 44 */ 45 EthernetTrailer (); 46 47 /** 48 * \brief Enable or disable FCS checking and calculations 49 * \param enable If true, enables FCS calculations. 50 */ 51 void EnableFcs (bool enable); 52 53 /** 54 * \brief Updates the Fcs Field to the correct FCS 55 * \param p Reference to a packet on which the FCS should be 56 * calculated. The packet should not currently contain an 57 * EthernetTrailer. 58 */ 59 void CalcFcs (Ptr<const Packet> p); 60 61 /** 62 * \brief Sets the FCS to a new value 63 * \param fcs New FCS value 64 */ 65 void SetFcs (uint32_t fcs); 66 67 /** 68 * \return the FCS contained in this trailer 69 */ 70 uint32_t GetFcs () const; 71 72 /** 73 * Calculate an FCS on the provided packet and check this value against 74 * the FCS found when the trailer was deserialized (the one in the transmitted 75 * packet). 76 * 77 * If FCS checking is disabled, this method will always 78 * return true. 79 * 80 * \param p Reference to the packet on which the FCS should be 81 * calculated. The packet should not contain an EthernetTrailer. 82 * 83 * \return Returns true if the Packet FCS matches the FCS in the trailer, 84 * false otherwise. 85 */ 86 bool CheckFcs (Ptr<const Packet> p) const; 87 88 /** 89 *\return Returns the size of the trailer 90 */ 91 uint32_t GetTrailerSize () const; 92 93 /** 94 * \brief Get the type ID. 95 * \return the object TypeId 96 */ 97 static TypeId GetTypeId (void); 98 virtual TypeId GetInstanceTypeId (void) const; 99 virtual void Print (std::ostream &os) const; 100 virtual uint32_t GetSerializedSize (void) const; 101 virtual void Serialize (Buffer::Iterator end) const; 102 virtual uint32_t Deserialize (Buffer::Iterator end); 103 private: 104 /** 105 * Enabled FCS calculations. If false, m_fcs is set to 0 and CheckFcs 106 * returns true. 107 */ 108 bool m_calcFcs; 109 uint32_t m_fcs; //!< Value of the fcs contained in the trailer 110 111 }; 112 113 } // namespace ns3 114 115 #endif /* ETHERNET_TRAILER_H */ 116