162 lines
3.1 KiB
C++
162 lines
3.1 KiB
C++
/* -*- Mode: C++; c-file-style: "gnu"; indent-tabs-mode:nil; -*- */
|
|
/*
|
|
* Copyright (c) 2005 INRIA
|
|
*
|
|
* 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
|
|
*
|
|
* Author: Emmanuelle Laprise <emmanuelle.laprise@bluekazoo.ca>
|
|
*/
|
|
|
|
#include "ns3/assert.h"
|
|
#include "ns3/log.h"
|
|
#include "ns3/trailer.h"
|
|
#include "ethernet-trailer.h"
|
|
|
|
NS_LOG_COMPONENT_DEFINE ("EthernetTrailer");
|
|
|
|
namespace ns3 {
|
|
|
|
NS_OBJECT_ENSURE_REGISTERED (EthernetTrailer);
|
|
|
|
EthernetTrailer::EthernetTrailer ()
|
|
: m_calcFcs (false),
|
|
m_fcs (0)
|
|
{}
|
|
|
|
void
|
|
EthernetTrailer::EnableFcs (bool enable)
|
|
{
|
|
m_calcFcs = enable;
|
|
}
|
|
|
|
bool
|
|
EthernetTrailer::CheckFcs (Ptr<const Packet> p) const
|
|
{
|
|
int len = p->GetSize ();
|
|
uint8_t *buffer;
|
|
uint32_t crc;
|
|
|
|
if (!m_calcFcs)
|
|
{
|
|
return true;
|
|
}
|
|
|
|
buffer = new uint8_t[len];
|
|
p->CopyData (buffer, len);
|
|
crc = DoCalcFcs (buffer, len);
|
|
delete[] buffer;
|
|
return (m_fcs == crc);
|
|
}
|
|
|
|
void
|
|
EthernetTrailer::CalcFcs (Ptr<const Packet> p)
|
|
{
|
|
int len = p->GetSize ();
|
|
uint8_t *buffer;
|
|
|
|
if (!m_calcFcs)
|
|
{
|
|
return;
|
|
}
|
|
|
|
buffer = new uint8_t[len];
|
|
p->CopyData (buffer, len);
|
|
m_fcs = DoCalcFcs (buffer, len);
|
|
delete[] buffer;
|
|
}
|
|
|
|
void
|
|
EthernetTrailer::SetFcs (uint32_t fcs)
|
|
{
|
|
m_fcs = fcs;
|
|
}
|
|
|
|
uint32_t
|
|
EthernetTrailer::GetFcs (void)
|
|
{
|
|
return m_fcs;
|
|
}
|
|
|
|
uint32_t
|
|
EthernetTrailer::GetTrailerSize (void) const
|
|
{
|
|
return GetSerializedSize();
|
|
}
|
|
|
|
TypeId
|
|
EthernetTrailer::GetTypeId (void)
|
|
{
|
|
static TypeId tid = TypeId ("ns3::EthernetTrailer")
|
|
.SetParent<Trailer> ()
|
|
.AddConstructor<EthernetTrailer> ()
|
|
;
|
|
return tid;
|
|
}
|
|
TypeId
|
|
EthernetTrailer::GetInstanceTypeId (void) const
|
|
{
|
|
return GetTypeId ();
|
|
}
|
|
void
|
|
EthernetTrailer::Print (std::ostream &os) const
|
|
{
|
|
os << "fcs=" << m_fcs;
|
|
}
|
|
uint32_t
|
|
EthernetTrailer::GetSerializedSize (void) const
|
|
{
|
|
return 4;
|
|
}
|
|
|
|
void
|
|
EthernetTrailer::Serialize (Buffer::Iterator end) const
|
|
{
|
|
Buffer::Iterator i = end;
|
|
i.Prev(GetSerializedSize());
|
|
|
|
i.WriteU32 (m_fcs);
|
|
}
|
|
uint32_t
|
|
EthernetTrailer::Deserialize (Buffer::Iterator end)
|
|
{
|
|
Buffer::Iterator i = end;
|
|
uint32_t size = GetSerializedSize();
|
|
i.Prev(size);
|
|
|
|
m_fcs = i.ReadU32 ();
|
|
|
|
return size;
|
|
}
|
|
|
|
// This code is copied from /lib/crc32.c in the linux kernel.
|
|
// It assumes little endian ordering.
|
|
uint32_t
|
|
EthernetTrailer::DoCalcFcs (uint8_t const *buffer, size_t len) const
|
|
{
|
|
uint32_t crc = 0xffffffff;
|
|
int i;
|
|
|
|
while (len--)
|
|
{
|
|
crc ^= *buffer++;
|
|
for (i = 0; i < 8; i++)
|
|
{
|
|
crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
|
|
}
|
|
}
|
|
return ~crc;
|
|
}
|
|
|
|
}; // namespace ns3
|