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

     2 /*

     3  * Copyright (c) 2009 MIRKO BANCHI

     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: Mirko Banchi <mk.banchi@gmail.com>

    19  */

    20 #include "ns3/log.h"

    21 

    22 #include "msdu-aggregator.h"

    23 #include "wifi-mac-header.h"

    24 

    25 NS_LOG_COMPONENT_DEFINE ("MsduAggregator");

    26 

    27 namespace ns3 {

    28 

    29 NS_OBJECT_ENSURE_REGISTERED (MsduAggregator);

    30 

    31 TypeId

    32 MsduAggregator::GetTypeId (void)

    33 {

    34   static TypeId tid = TypeId ("ns3::MsduAggregator")

    35     .SetParent<Object> ()

    36     ;

    37   return tid;

    38 }

    39 

    40 MsduAggregator::DeaggregatedMsdus

    41 MsduAggregator::Deaggregate (Ptr<Packet> aggregatedPacket)

    42 {

    43   NS_LOG_FUNCTION_NOARGS ();

    44   DeaggregatedMsdus set;

    45   

    46   AmsduSubframeHeader hdr;

    47   uint32_t maxSize = aggregatedPacket->GetSize ();

    48   // The worst condition is: two aggregated packets with no padding.

    49   // 28 bytes is the size of two Amsdu subframe headers.

    50   uint8_t *buffer = new uint8_t[maxSize-28];

    51   uint32_t padding;

    52   uint32_t deserialized = 0;

    53 

    54   while (deserialized < maxSize)

    55    {

    56      deserialized += aggregatedPacket->RemoveHeader (hdr);

    57      deserialized += aggregatedPacket->CopyData (buffer, hdr.GetLength ());

    58      aggregatedPacket->RemoveAtStart (hdr.GetLength ());

    59      

    60      padding = (4 - ((hdr.GetLength () + 14) %4 )) % 4;

    61   

    62      if (padding > 0)

    63        {

    64          aggregatedPacket->RemoveAtStart (padding);

    65          deserialized += padding;

    66        }

    67      //a new packet is created with the content of extracted msdu

    68      Ptr<Packet> p = Create<Packet> (buffer, hdr.GetLength ());

    69      

    70      std::pair<Ptr<Packet>, AmsduSubframeHeader> packetHdr (p,hdr);

    71      set.push_back (packetHdr);

    72    }

    73   delete [] buffer;

    74   NS_LOG_INFO ("Deaggreated A-MSDU: extracted "<< set.size () << " MSDUs");

    75   return set;

    76 }

    77 

    78 } //namespace ns3