A Discrete-Event Network Simulator
API
 All Classes Namespaces Files Functions Variables Typedefs Enumerations Enumerator Friends Groups Pages
ns3::EthernetTrailer Class Reference

Packet trailer for Ethernet. More...

#include <ethernet-trailer.h>

+ Inheritance diagram for ns3::EthernetTrailer:

Public Member Functions

 EthernetTrailer ()
 Construct a null ethernet trailer.
 
void CalcFcs (Ptr< const Packet > p)
 Updates the Fcs Field to the correct FCS. More...
 
bool CheckFcs (Ptr< const Packet > p) const
 
virtual uint32_t Deserialize (Buffer::Iterator end)
 
void EnableFcs (bool enable)
 Enable or disable FCS checking and calculations. More...
 
uint32_t GetFcs ()
 
virtual TypeId GetInstanceTypeId (void) const
 
virtual uint32_t GetSerializedSize (void) const
 
uint32_t GetTrailerSize () const
 
virtual void Print (std::ostream &os) const
 
virtual void Serialize (Buffer::Iterator end) const
 
void SetFcs (uint32_t fcs)
 Sets the FCS to a new value. More...
 
- Public Member Functions inherited from ns3::ObjectBase
void GetAttribute (std::string name, AttributeValue &value) const
 
bool GetAttributeFailSafe (std::string name, AttributeValue &attribute) const
 
void SetAttribute (std::string name, const AttributeValue &value)
 
bool SetAttributeFailSafe (std::string name, const AttributeValue &value)
 
bool TraceConnect (std::string name, std::string context, const CallbackBase &cb)
 
bool TraceConnectWithoutContext (std::string name, const CallbackBase &cb)
 
bool TraceDisconnect (std::string name, std::string context, const CallbackBase &cb)
 
bool TraceDisconnectWithoutContext (std::string name, const CallbackBase &cb)
 

Static Public Member Functions

static TypeId GetTypeId (void)
 
- Static Public Member Functions inherited from ns3::Trailer
static TypeId GetTypeId (void)
 
- Static Public Member Functions inherited from ns3::Chunk
static TypeId GetTypeId (void)
 
- Static Public Member Functions inherited from ns3::ObjectBase
static TypeId GetTypeId (void)
 

Private Member Functions

uint32_t DoCalcFcs (uint8_t const *buffer, size_t len) const
 Value of the fcs contained in the trailer.
 

Private Attributes

bool m_calcFcs
 
uint32_t m_fcs
 

Additional Inherited Members

- Protected Member Functions inherited from ns3::ObjectBase
void ConstructSelf (const AttributeConstructionList &attributes)
 
virtual void NotifyConstructionCompleted (void)
 

Detailed Description

Packet trailer for Ethernet.

This class can be used to add and verify the FCS at the end of an Ethernet packet.

Doxygen introspection did not find any typical Config paths.
No Attributes are defined for this type.
No TraceSources are defined for this type.

Definition at line 39 of file ethernet-trailer.h.

Member Function Documentation

void ns3::EthernetTrailer::CalcFcs ( Ptr< const Packet p)

Updates the Fcs Field to the correct FCS.

Parameters
pReference to a packet on which the FCS should be calculated. The packet should not currently contain an EthernetTrailer.

Definition at line 67 of file ethernet-trailer.cc.

References ns3::Packet::CopyData(), DoCalcFcs(), ns3::Packet::GetSize(), m_calcFcs, and NS_LOG_FUNCTION.

Referenced by ns3::CsmaNetDevice::AddHeader().

bool ns3::EthernetTrailer::CheckFcs ( Ptr< const Packet p) const

Calculate an FCS on the provided packet and check this value against the FCS found when the trailer was deserialized (the one in the transmitted packet).

If FCS checking is disabled, this method will always return true.

Parameters
pReference to the packet on which the FCS should be calculated. The packet should not contain an EthernetTrailer.
Returns
Returns true if the Packet FCS matches the FCS in the trailer, false otherwise.

Definition at line 47 of file ethernet-trailer.cc.

References ns3::Packet::CopyData(), DoCalcFcs(), ns3::Packet::GetSize(), m_calcFcs, and NS_LOG_FUNCTION.

Referenced by ns3::CsmaNetDevice::Receive().

uint32_t ns3::EthernetTrailer::Deserialize ( Buffer::Iterator  end)
virtual
Parameters
endan iterator which points to the end of the buffer where the trailer should be read from.
Returns
the number of bytes read.

This method is used by Packet::RemoveTrailer to re-create a trailer from the byte buffer of a packet. The data read is expected to match bit-for-bit the representation of this trailer in real networks. The input iterator points to the end of the area where the data shall be written. This method is thus expected to call Buffer::Iterator::Prev prio to actually reading any data.

Implements ns3::Trailer.

Definition at line 142 of file ethernet-trailer.cc.

References GetSerializedSize(), NS_LOG_FUNCTION, ns3::Buffer::Iterator::Prev(), and ns3::Buffer::Iterator::ReadU32().

void ns3::EthernetTrailer::EnableFcs ( bool  enable)

Enable or disable FCS checking and calculations.

Parameters
enableIf true, enables FCS calculations.

Definition at line 40 of file ethernet-trailer.cc.

References m_calcFcs, and NS_LOG_FUNCTION.

Referenced by ns3::CsmaNetDevice::AddHeader(), and ns3::CsmaNetDevice::Receive().

uint32_t ns3::EthernetTrailer::GetFcs ( void  )
Returns
the FCS contained in this trailer

Definition at line 92 of file ethernet-trailer.cc.

References NS_LOG_FUNCTION.

TypeId ns3::EthernetTrailer::GetInstanceTypeId ( void  ) const
virtual
Returns
the TypeId associated to the most-derived type of this instance.

This method is typically implemented by ns3::Object::GetInstanceTypeId but some classes which derive from ns3::ObjectBase directly have to implement it themselves.

Implements ns3::ObjectBase.

Definition at line 115 of file ethernet-trailer.cc.

uint32_t ns3::EthernetTrailer::GetSerializedSize ( void  ) const
virtual
Returns
the expected size of the trailer.

This method is used by Packet::AddTrailer to store a trailer into the byte buffer of a packet. This method should return the number of bytes which are needed to store the full trailer data by Serialize.

Implements ns3::Trailer.

Definition at line 126 of file ethernet-trailer.cc.

References NS_LOG_FUNCTION.

Referenced by Deserialize(), GetTrailerSize(), and Serialize().

uint32_t ns3::EthernetTrailer::GetTrailerSize ( void  ) const
Returns
Returns the size of the trailer

Definition at line 99 of file ethernet-trailer.cc.

References GetSerializedSize(), and NS_LOG_FUNCTION.

void ns3::EthernetTrailer::Print ( std::ostream &  os) const
virtual
Parameters
osoutput stream This method is used by Packet::Print to print the content of a trailer as ascii data to a c++ output stream. Although the trailer is free to format its output as it wishes, it is recommended to follow a few rules to integrate with the packet pretty printer: start with flags, small field values located between a pair of parens. Values should be separated by whitespace. Follow the parens with the important fields, separated by whitespace. i.e.: (field1 val1 field2 val2 field3 val3) field4 val4 field5 val5

Implements ns3::Trailer.

Definition at line 120 of file ethernet-trailer.cc.

References NS_LOG_FUNCTION.

void ns3::EthernetTrailer::Serialize ( Buffer::Iterator  start) const
virtual
Parameters
startan iterator which points to where the trailer should be written.

This method is used by Packet::AddTrailer to store a header into the byte buffer of a packet. The data written is expected to match bit-for-bit the representation of this trailer in real networks. The input iterator points to the end of the area where the data shall be written. This method is thus expected to call Buffer::Iterator::Prev prior to actually writing any data.

Implements ns3::Trailer.

Definition at line 133 of file ethernet-trailer.cc.

References GetSerializedSize(), NS_LOG_FUNCTION, ns3::Buffer::Iterator::Prev(), and ns3::Buffer::Iterator::WriteU32().

void ns3::EthernetTrailer::SetFcs ( uint32_t  fcs)

Sets the FCS to a new value.

Parameters
fcsNew FCS value

Definition at line 85 of file ethernet-trailer.cc.

References NS_LOG_FUNCTION.

Member Data Documentation

bool ns3::EthernetTrailer::m_calcFcs
private

Enabled FCS calculations. If false, m_fcs is set to 0 and CheckFcs returns true.

Definition at line 104 of file ethernet-trailer.h.

Referenced by CalcFcs(), CheckFcs(), and EnableFcs().


The documentation for this class was generated from the following files: