Packet trailer for Ethernet. More...

#include <ethernet-trailer.h>

Inheritance diagram for ns3::EthernetTrailer:

Collaboration 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.
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.
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.
Public Member Functions inherited from ns3::Trailer
virtual	~Trailer ()

Static Public Member Functions
static TypeId	GetTypeId (void)
	This method returns the TypeId associated to ns3::EthernetTrailer.

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.

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

Constructor & Destructor Documentation

ns3::EthernetTrailer::EthernetTrailer ( )

Construct a null ethernet trailer.

Definition at line 32 of file ethernet-trailer.cc.

Member Function Documentation

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

Updates the Fcs Field to the correct FCS.

Parameters

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

Definition at line 64 of file ethernet-trailer.cc.

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

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

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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

p	Reference 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 45 of file ethernet-trailer.cc.

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

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

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uint32_t ns3::EthernetTrailer::Deserialize ( Buffer::Iterator end )

virtual

Parameters

end	an 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 132 of file ethernet-trailer.cc.

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

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uint32_t ns3::EthernetTrailer::DoCalcFcs	(	uint8_t const *	buffer,
		size_t	len
	)		const

private

Value of the fcs contained in the trailer.

Definition at line 146 of file ethernet-trailer.cc.

Referenced by CalcFcs(), and CheckFcs().

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

Enable or disable FCS checking and calculations.

Parameters

enable If true, enables FCS calculations.

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

References m_calcFcs.

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

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uint32_t ns3::EthernetTrailer::GetFcs ( void )

Returns: the FCS contained in this trailer

Definition at line 87 of file ethernet-trailer.cc.

References m_fcs.

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 108 of file ethernet-trailer.cc.

References GetTypeId().

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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 118 of file ethernet-trailer.cc.

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

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uint32_t ns3::EthernetTrailer::GetTrailerSize ( void ) const

Returns: Returns the size of the trailer

Definition at line 93 of file ethernet-trailer.cc.

References GetSerializedSize().

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TypeId ns3::EthernetTrailer::GetTypeId ( void )

static

This method returns the TypeId associated to ns3::EthernetTrailer.

No Attributes defined for this type.
No TraceSources defined for this type.

Reimplemented from ns3::Trailer.

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

References ns3::TypeId::SetParent().

Referenced by GetInstanceTypeId().

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void ns3::EthernetTrailer::Print ( std::ostream & os ) const

virtual

Parameters

os output 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 113 of file ethernet-trailer.cc.

References m_fcs.

void ns3::EthernetTrailer::Serialize ( Buffer::Iterator start ) const

virtual

Parameters

start an 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 124 of file ethernet-trailer.cc.

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

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