ns3::Socket Class Reference
[Socket]

A low-level Socket API based loosely on the BSD Socket API.

A few things to keep in mind about this type of socket:

• it uses ns-3 API constructs such as class ns3::Address instead of C-style structs
• in contrast to the original BSD socket API, this API is asynchronous: it does not contain blocking calls. Sending and receiving operations must make use of the callbacks provided.
• It also uses class ns3::Packet as a fancy byte buffer, allowing data to be passed across the API using an ns-3 Packet instead of a raw data pointer.
• Not all of the full POSIX sockets API is supported.

More...

#include <socket.h>

Inheritance diagram for ns3::Socket:

[legend]

Collaboration diagram for ns3::Socket:

[legend]

List of all members.

Public Member Functions
virtual enum Socket::SocketErrno	GetErrno (void) const =0
virtual Ptr< Node >	GetNode (void) const =0
void	SetConnectCallback (Callback< void, Ptr< Socket > > connectionSucceeded, Callback< void, Ptr< Socket > > connectionFailed)
void	SetAcceptCallback (Callback< bool, Ptr< Socket >, const Address & > connectionRequest, Callback< void, Ptr< Socket >, const Address & > newConnectionCreated)
	Accept connection requests from remote hosts.
void	SetDataSentCallback (Callback< void, Ptr< Socket >, uint32_t > dataSent)
	Notify application when a packet has been sent from transport protocol (non-standard socket call).
void	SetSendCallback (Callback< void, Ptr< Socket >, uint32_t > sendCb)
	Notify application when space in transmit buffer is added.
void	SetRecvCallback (Callback< void, Ptr< Socket > >)
	Notify application when new data is available to be read.
virtual int	Bind (const Address &address)=0
virtual int	Bind ()=0
virtual int	Close (void)=0
	Close a socket.
virtual int	ShutdownSend (void)=0
virtual int	ShutdownRecv (void)=0
virtual int	Connect (const Address &address)=0
	Initiate a connection to a remote host.
virtual int	Listen (void)=0
	Listen for incoming connections.
virtual uint32_t	GetTxAvailable (void) const =0
	Returns the number of bytes which can be sent in a single call to Send.
virtual int	Send (Ptr< Packet > p, uint32_t flags)=0
	Send data (or dummy data) to the remote host.
virtual int	SendTo (Ptr< Packet > p, uint32_t flags, const Address &toAddress)=0
	Send data to a specified peer.
virtual uint32_t	GetRxAvailable (void) const =0
virtual Ptr< Packet >	Recv (uint32_t maxSize, uint32_t flags)=0
	Read data from the socket.
virtual Ptr< Packet >	RecvFrom (uint32_t maxSize, uint32_t flags, Address &fromAddress)=0
	Read a single packet from the socket and retrieve the sender address.
int	Send (Ptr< Packet > p)
	Send data (or dummy data) to the remote host.
int	Send (const uint8_t *buf, uint32_t size, uint32_t flags)
	Send data (or dummy data) to the remote host.
int	SendTo (const uint8_t *buf, uint32_t size, uint32_t flags, const Address &address)
	Send data to a specified peer.
Ptr< Packet >	Recv (void)
	Read a single packet from the socket.
int	Recv (uint8_t *buf, uint32_t size, uint32_t flags)
	Recv data (or dummy data) from the remote host.
Ptr< Packet >	RecvFrom (Address &fromAddress)
	Read a single packet from the socket and retrieve the sender address.
int	RecvFrom (uint8_t *buf, uint32_t size, uint32_t flags, Address &fromAddress)
	Read a single packet from the socket and retrieve the sender address.
virtual int	GetSockName (Address &address) const =0
Static Public Member Functions
static Ptr< Socket >	CreateSocket (Ptr< Node > node, TypeId tid)
Protected Member Functions
virtual void	DoDispose (void)

---

Detailed Description

A low-level Socket API based loosely on the BSD Socket API.

A few things to keep in mind about this type of socket:

• it uses ns-3 API constructs such as class ns3::Address instead of C-style structs
• in contrast to the original BSD socket API, this API is asynchronous: it does not contain blocking calls. Sending and receiving operations must make use of the callbacks provided.
• It also uses class ns3::Packet as a fancy byte buffer, allowing data to be passed across the API using an ns-3 Packet instead of a raw data pointer.
• Not all of the full POSIX sockets API is supported.

Other than that, it tries to stick to the BSD API to make it easier for those who know the BSD API to use this API. More details are provided in the ns-3 tutorial.

---

Member Function Documentation

virtual int ns3::Socket::Bind

(

)

[pure virtual]

Allocate a local endpoint for this socket.

Returns:

0 on success, -1 on failure.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::Bind

(

const Address &

address

)

[pure virtual]

Parameters:

address

the address to try to allocate

Returns:

0 on success, -1 on failure.

Allocate a local endpoint for this socket.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::Close

(

void

)

[pure virtual]

Close a socket.

After the Close call, the socket is no longer valid, and cannot safely be used for subsequent operations.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::Connect

(

const Address &

address

)

[pure virtual]

Initiate a connection to a remote host.

Parameters:

address

Address of remote.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

static Ptr<Socket> ns3::Socket::CreateSocket	(	Ptr< Node >	node,
		TypeId	tid
	)			[static]

This method wraps the creation of sockets that is performed by a socket factory on a given node based on a TypeId.

Returns:

A smart pointer to a newly created socket.

Parameters:

	node	The node on which to create the socket
	tid	The TypeId of the socket to create

virtual void ns3::Socket::DoDispose

(

void

)

[protected, virtual]

This method is called by Object::Dispose or by the object's destructor, whichever comes first.

Subclasses are expected to implement their real destruction code in an overriden version of this method and chain up to their parent's implementation once they are done. i.e., for simplicity, the destructor of every subclass should be empty and its content should be moved to the associated DoDispose method.

Reimplemented from ns3::Object.

Reimplemented in ns3::PacketSocket.

virtual enum Socket::SocketErrno ns3::Socket::GetErrno

(

void

)

const [pure virtual]

Returns:

the errno associated to the last call which failed in this socket. Each socket's errno is initialized to zero when the socket is created.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual Ptr<Node> ns3::Socket::GetNode

(

void

)

const [pure virtual]

Returns:

the node this socket is associated with.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual uint32_t ns3::Socket::GetRxAvailable

(

void

)

const [pure virtual]

Return number of bytes which can be returned from one or multiple calls to Recv. Must be possible to call this method from the Recv callback.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::GetSockName

(

Address &

address

)

const [pure virtual]

Returns:

the address name this socket is associated with.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual uint32_t ns3::Socket::GetTxAvailable

(

void

)

const [pure virtual]

Returns the number of bytes which can be sent in a single call to Send.

For datagram sockets, this returns the number of bytes that can be passed atomically through the underlying protocol.

For stream sockets, this returns the available space in bytes left in the transmit buffer.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::Listen

(

void

)

[pure virtual]

Listen for incoming connections.

Returns:

0 on success, -1 on error (in which case errno is set).

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

int ns3::Socket::Recv	(	uint8_t *	buf,
		uint32_t	size,
		uint32_t	flags
	)

Recv data (or dummy data) from the remote host.

This method is provided so as to have an API which is closer in appearance to that of real network or BSD sockets.

If the underlying packet was carring null (fake) data, this buffer will be zeroed up to the length specified by the return value.

Parameters:

	buf	A pointer to a raw byte buffer to write the data to.
	size	Number of bytes (at most) to copy to buf
	flags	any flags to pass to the socket

Returns:

number of bytes copied into buf

Ptr<Packet> ns3::Socket::Recv

(

void

)

Read a single packet from the socket.

Overloaded version of Recv(maxSize, flags) with maxSize implicitly set to maximum sized integer, and flags set to zero.

Returns:

Ptr<Packet> of the next in-sequence packet. Returns 0 if the socket cannot return a next in-sequence packet.

virtual Ptr<Packet> ns3::Socket::Recv	(	uint32_t	maxSize,
		uint32_t	flags
	)			[pure virtual]

Read data from the socket.

This function matches closely in semantics to the recv() function call in the standard C library (libc): ssize_t recv (int s, void *buf, size_t len, int flags); except that the receive I/O is asynchronous. This is the primary Recv method at this low-level API and must be implemented by subclasses.

This method is normally used only on a connected socket. In a typical blocking sockets model, this call would block until at least one byte is returned or the connection closes. In ns-3 at this API, the call returns immediately in such a case and returns 0 if nothing is available to be read. However, an application can set a callback, ns3::SetRecvCallback, to be notified of data being available to be read (when it conceptually unblocks); this is an asynchronous I/O model for recv().

This variant of Recv() uses class ns3::Packet to encapsulate data, rather than providing a raw pointer and length field. This allows an ns-3 application to attach tags if desired (such as a flow ID) and may allow the simulator to avoid some data copies. Despite the appearance of receiving Packets on a stream socket, just think of it as a fancy byte buffer with streaming semantics.

The semantics depend on the type of socket. For a datagram socket, each Recv() returns the data from at most one Send(), and order is not necessarily preserved. For a stream socket, the bytes are delivered in order, and on-the-wire packet boundaries are not preserved.

The flags argument is formed by or'ing one or more of the values: MSG_OOB process out-of-band data MSG_PEEK peek at incoming message None of these flags are supported for now.

Some variants of Recv() are supported as additional API, including RecvFrom(), overloaded Recv() without arguments, and variants that use raw character buffers.

Parameters:

	maxSize	reader will accept packet up to maxSize
	flags	Socket control flags

Returns:

Ptr<Packet> of the next in-sequence packet. Returns 0 if the socket cannot return a next in-sequence packet conforming to the maxSize and flags.

See also:

SetRecvCallback

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

int ns3::Socket::RecvFrom	(	uint8_t *	buf,
		uint32_t	size,
		uint32_t	flags,
		Address &	fromAddress
	)

Read a single packet from the socket and retrieve the sender address.

This method is provided so as to have an API which is closer in appearance to that of real network or BSD sockets.

Parameters:

	buf	A pointer to a raw byte buffer to write the data to. If the underlying packet was carring null (fake) data, this buffer will be zeroed up to the length specified by the return value.
	size	Number of bytes (at most) to copy to buf
	flags	any flags to pass to the socket
	fromAddress	output parameter that will return the address of the sender of the received packet, if any. Remains untouched if no packet is received.

Returns:

number of bytes copied into buf

Ptr<Packet> ns3::Socket::RecvFrom

(

Address &

fromAddress

)

Read a single packet from the socket and retrieve the sender address.

Calls RecvFrom (maxSize, flags, fromAddress) with maxSize implicitly set to maximum sized integer, and flags set to zero.

Parameters:

fromAddress

output parameter that will return the address of the sender of the received packet, if any. Remains untouched if no packet is received.

Returns:

Ptr<Packet> of the next in-sequence packet. Returns 0 if the socket cannot return a next in-sequence packet.

virtual Ptr<Packet> ns3::Socket::RecvFrom	(	uint32_t	maxSize,
		uint32_t	flags,
		Address &	fromAddress
	)			[pure virtual]

Read a single packet from the socket and retrieve the sender address.

Calls Recv(maxSize, flags) with maxSize implicitly set to maximum sized integer, and flags set to zero.

This method has similar semantics to Recv () but subclasses may want to provide checks on socket state, so the implementation is pushed to subclasses.

Parameters:

	maxSize	reader will accept packet up to maxSize
	flags	Socket control flags
	fromAddress	output parameter that will return the address of the sender of the received packet, if any. Remains untouched if no packet is received.

Returns:

Ptr<Packet> of the next in-sequence packet. Returns 0 if the socket cannot return a next in-sequence packet.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

int ns3::Socket::Send	(	const uint8_t *	buf,
		uint32_t	size,
		uint32_t	flags
	)

Send data (or dummy data) to the remote host.

This method is provided so as to have an API which is closer in appearance to that of real network or BSD sockets.

Parameters:

	buf	A pointer to a raw byte buffer of some data to send. If this buffer is 0, we send dummy data whose size is specified by the second parameter
	size	the number of bytes to copy from the buffer
	flags	Socket control flags

int ns3::Socket::Send

(

Ptr< Packet >

p

)

Send data (or dummy data) to the remote host.

Overloaded version of Send(..., flags) with flags set to zero.

Parameters:

p

ns3::Packet to send

Returns:

the number of bytes accepted for transmission if no error occurs, and -1 otherwise.

virtual int ns3::Socket::Send	(	Ptr< Packet >	p,
		uint32_t	flags
	)			[pure virtual]

Send data (or dummy data) to the remote host.

This function matches closely in semantics to the send() function call in the standard C library (libc): ssize_t send (int s, const void *msg, size_t len, int flags); except that the send I/O is asynchronous. This is the primary Send method at this low-level API and must be implemented by subclasses.

In a typical blocking sockets model, this call would block upon lack of space to hold the message to be sent. In ns-3 at this API, the call returns immediately in such a case, but the callback registered with SetSendCallback() is invoked when the socket has space (when it conceptually unblocks); this is an asynchronous I/O model for send().

This variant of Send() uses class ns3::Packet to encapsulate data, rather than providing a raw pointer and length field. This allows an ns-3 application to attach tags if desired (such as a flow ID) and may allow the simulator to avoid some data copies. Despite the appearance of sending Packets on a stream socket, just think of it as a fancy byte buffer with streaming semantics.

If either the message buffer within the Packet is too long to pass atomically through the underlying protocol (for datagram sockets), or the message buffer cannot entirely fit in the transmit buffer (for stream sockets), -1 is returned and SocketErrno is set to ERROR_MSGSIZE. If the packet does not fit, the caller can split the Packet (based on information obtained from GetTxAvailable) and reattempt to send the data.

The flags argument is formed by or'ing one or more of the values: MSG_OOB process out-of-band data MSG_DONTROUTE bypass routing, use direct interface These flags are _unsupported_ as of ns-3.1.

Parameters:

	p	ns3::Packet to send
	flags	Socket control flags

Returns:

the number of bytes accepted for transmission if no error occurs, and -1 otherwise.

See also:

SetSendCallback

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

int ns3::Socket::SendTo	(	const uint8_t *	buf,
		uint32_t	size,
		uint32_t	flags,
		const Address &	address
	)

Send data to a specified peer.

This method is provided so as to have an API which is closer in appearance to that of real network or BSD sockets.

Parameters:

	buf	A pointer to a raw byte buffer of some data to send. If this is 0, we send dummy data whose size is specified by the third parameter
	size	the number of bytes to copy from the buffer
	flags	Socket control flags
	address	IP Address of remote host

Returns:

-1 in case of error or the number of bytes copied in the internal buffer and accepted for transmission.

virtual int ns3::Socket::SendTo	(	Ptr< Packet >	p,
		uint32_t	flags,
		const Address &	toAddress
	)			[pure virtual]

Send data to a specified peer.

This method has similar semantics to Send () but subclasses may want to provide checks on socket state, so the implementation is pushed to subclasses.

Parameters:

	p	packet to send
	flags	Socket control flags
	toAddress	IP Address of remote host

Returns:

-1 in case of error or the number of bytes copied in the internal buffer and accepted for transmission.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

void ns3::Socket::SetAcceptCallback	(	Callback< bool, Ptr< Socket >, const Address & >	connectionRequest,
		Callback< void, Ptr< Socket >, const Address & >	newConnectionCreated
	)

Accept connection requests from remote hosts.

Parameters:

	connectionRequest	Callback for connection request from peer. This user callback is passed a pointer to this socket, the ip address and the port number of the connection originator. This callback must return true to accept the incoming connection, false otherwise. If the connection is accepted, the "newConnectionCreated" callback will be invoked later to give access to the user to the socket created to match this new connection. If the user does not explicitly specify this callback, all incoming connections will be refused.
	newConnectionCreated	Callback for new connection: when a new is accepted, it is created and the corresponding socket is passed back to the user through this callback. This user callback is passed a pointer to the new socket, and the ip address and port number of the connection originator.

void ns3::Socket::SetConnectCallback	(	Callback< void, Ptr< Socket > >	connectionSucceeded,
		Callback< void, Ptr< Socket > >	connectionFailed
	)

Parameters:

	connectionSucceeded	this callback is invoked when the connection request initiated by the user is successfully completed. The callback is passed back a pointer to the same socket object.
	connectionFailed	this callback is invoked when the connection request initiated by the user is unsuccessfully completed. The callback is passed back a pointer to the same socket object.

void ns3::Socket::SetDataSentCallback

(

Callback< void, Ptr< Socket >, uint32_t >

dataSent

)

Notify application when a packet has been sent from transport protocol (non-standard socket call).

Parameters:

dataSent

Callback for the event that data is sent from the underlying transport protocol. This callback is passed a pointer to the socket, and the number of bytes sent.

void ns3::Socket::SetRecvCallback

(

Callback< void, Ptr< Socket > >

)

Notify application when new data is available to be read.

This callback is intended to notify a socket that would have been blocked in a blocking socket model that data is available to be read.

void ns3::Socket::SetSendCallback

(

Callback< void, Ptr< Socket >, uint32_t >

sendCb

)

Notify application when space in transmit buffer is added.

This callback is intended to notify a socket that would have been blocked in a blocking socket model that space is available in the transmit buffer and that it can call Send() again.

Parameters:

sendCb

Callback for the event that the socket transmit buffer fill level has decreased. This callback is passed a pointer to the socket, and the number of bytes available for writing into the buffer (an absolute value). If there is no transmit buffer limit, a maximum-sized integer is always returned.

virtual int ns3::Socket::ShutdownRecv

(

void

)

[pure virtual]

Returns:

zero on success, -1 on failure.

Do not allow any further Recv calls. This method is typically implemented for Tcp sockets by a half close.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

virtual int ns3::Socket::ShutdownSend

(

void

)

[pure virtual]

Returns:

zero on success, -1 on failure.

Do not allow any further Send calls. This method is typically implemented for Tcp sockets by a half close.

Implemented in ns3::NscTcpSocketImpl, ns3::TcpSocketImpl, ns3::UdpSocketImpl, and ns3::PacketSocket.

---

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

• src/node/socket.h