#include <Socket.h>

Inheritance diagram for Socket:

Public Member Functions
virtual	~Socket ()=default
	Destroy a socket. More...

virtual nsapi_error_t	close ()=0
	Closes the socket. More...

virtual nsapi_error_t	connect (const SocketAddress &address)=0
	Connects socket to a remote address. More...

virtual nsapi_size_or_error_t	send (const void *data, nsapi_size_t size)=0
	Send data on a socket. More...

virtual nsapi_size_or_error_t	recv (void *data, nsapi_size_t size)=0
	Receive data from a socket. More...

virtual nsapi_size_or_error_t	sendto (const SocketAddress &address, const void *data, nsapi_size_t size)=0
	Send a message on a socket. More...

virtual nsapi_size_or_error_t	recvfrom (SocketAddress address, void data, nsapi_size_t size)=0
	Receive a data from a socket. More...

virtual nsapi_size_or_error_t	sendto_control (const SocketAddress &address, const void data, nsapi_size_t size, nsapi_msghdr_t control, nsapi_size_t control_size)=0
	Send a message on a socket. More...

virtual nsapi_size_or_error_t	recvfrom_control (SocketAddress address, void data, nsapi_size_t size, nsapi_msghdr_t *control, nsapi_size_t control_size)=0
	Receive a data from a socket. More...

virtual nsapi_error_t	bind (const SocketAddress &address)=0
	Bind a specific address to a socket. More...

virtual void	set_blocking (bool blocking)=0
	Set blocking or non-blocking mode of the socket. More...

virtual void	set_timeout (int timeout)=0
	Set timeout on blocking socket operations. More...

virtual void	sigio (mbed::Callback< void()> func)=0
	Register a callback on state change of the socket. More...

virtual nsapi_error_t	setsockopt (int level, int optname, const void *optval, unsigned optlen)=0
	Set socket options. More...

virtual nsapi_error_t	getsockopt (int level, int optname, void optval, unsigned optlen)=0
	Get socket options. More...

virtual Socket *	accept (nsapi_error_t *error=NULL)=0
	Accepts a connection on a socket. More...

virtual nsapi_error_t	listen (int backlog=1)=0
	Listen for incoming connections. More...

virtual nsapi_error_t	getpeername (SocketAddress *address)=0
	Get the remote-end peer associated with this socket. More...

Detailed Description

Socket interface.

This class defines the Mbed OS Socket API. Socket is an abstract interface for communicating with remote endpoints.

This API is intended for applications and libraries instead of protocol-specific implementations. For example, TCPSocket and UDPSocket are implementations of the Socket interface. Socket API is intentionally not protocol-specific, and allows all protocol to provide the same API regardless of the underlying transport mechanism.

Definition at line 40 of file Socket.h.

Constructor & Destructor Documentation

◆ ~Socket()

virtual ~Socket ( )

virtualdefault

Destroy a socket.

Closes socket if the socket is still open.

Member Function Documentation

◆ close()

virtual nsapi_error_t close ( )

pure virtual

Closes the socket.

Closes any open connection and deallocates any memory associated with the socket. Called from destructor if socket is not closed.

Returns: NSAPI_ERROR_OK on success. Negative subclass-dependent error code on failure.

Implemented in CellularNonIPSocket, DTLSSocketWrapper, InternetSocket, and TLSSocketWrapper.

◆ connect()

virtual nsapi_error_t connect ( const SocketAddress & address )

pure virtual

Connects socket to a remote address.

Attempts to make connection on connection-mode protocol or set or reset the peer address on connectionless protocol.

Connectionless protocols also use the connected address to filter incoming packets for recv() and recvfrom() calls.

To reset the peer address, there must be zero initialized(default constructor) SocketAddress objects in the address parameter.

Note: If connect() fails it is recommended to close the Socket and create a new one before attempting to reconnect.

Parameters

address The SocketAddress of the remote peer.

Returns: NSAPI_ERROR_OK on success. Negative subclass-dependent error code on failure.

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, TLSSocket, and TLSSocketWrapper.

◆ send()

virtual nsapi_size_or_error_t send	(	const void *	data,
		nsapi_size_t	size
	)

pure virtual

Send data on a socket.

The socket must be connected to a remote host before send() call. Returns the number of bytes sent from the buffer. In case of connectionless socket, sends data to pre-specified remote.

By default, send blocks until all data is sent. If socket is set to non-blocking or times out, a partial amount can be written. NSAPI_ERROR_WOULD_BLOCK is returned if no data was written.

Parameters

data	Buffer of data to send to the host.
size	Size of the buffer in bytes.

Returns: NSAPI_ERROR_OK on success. Negative subclass-dependent error code on failure.

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ recv()

virtual nsapi_size_or_error_t recv	(	void *	data,
		nsapi_size_t	size
	)

pure virtual

Receive data from a socket.

Receive data from connected socket, or in the case of connectionless socket, equivalent to calling recvfrom(NULL, data, size).

If socket is connected, only packets coming from connected peer address are accepted.

Note: recv() is allowed write to data buffer even if an error occurs.

By default, recv blocks until some data is received. If socket is set to non-blocking or times out, NSAPI_ERROR_WOULD_BLOCK can be returned to indicate no data.

Parameters

data	Destination buffer for data received from the host.
size	Size of the buffer in bytes.

Returns: Number of received bytes on success, negative, subclass-dependent error code on failure. If no data is available to be received and the peer has performed an orderly shutdown, recv() returns 0.

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ sendto()

virtual nsapi_size_or_error_t sendto	(	const SocketAddress &	address,
		const void *	data,
		nsapi_size_t	size
	)

pure virtual

Send a message on a socket.

The sendto() function sends a message through a connection-mode or connectionless-mode socket. If the socket is a connectionless-mode socket, the message is sent to the address specified. If the socket is a connected-mode socket, address is ignored.

By default, sendto blocks until data is sent. If socket is set to non-blocking or times out, NSAPI_ERROR_WOULD_BLOCK is returned immediately.

Parameters

address	Remote address
data	Buffer of data to send to the host
size	Size of the buffer in bytes

Returns: Number of sent bytes on success, negative subclass-dependent error code on failure

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ recvfrom()

virtual nsapi_size_or_error_t recvfrom	(	SocketAddress *	address,
		void *	data,
		nsapi_size_t	size
	)

pure virtual

Receive a data from a socket.

Receives a data and stores the source address in address if address is not NULL. Returns the number of bytes written into the buffer.

If socket is connected, only packets coming from connected peer address are accepted.

Note: recvfrom() is allowed write to address and data buffers even if error occurs.

By default, recvfrom blocks until a datagram is received. If socket is set to non-blocking or times out with no data, NSAPI_ERROR_WOULD_BLOCK is returned.

Parameters

address	Destination for the source address or NULL
data	Destination buffer for datagram received from the host
size	Size of the buffer in bytes

Returns: Number of received bytes on success, negative subclass-dependent error code on failure

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ sendto_control()

virtual nsapi_size_or_error_t sendto_control	(	const SocketAddress &	address,
		const void *	data,
		nsapi_size_t	size,
		nsapi_msghdr_t *	control,
		nsapi_size_t	control_size
	)

pure virtual

Send a message on a socket.

The sendto_control() function sends a message through a connection-mode or connectionless-mode socket. If the socket is a connectionless-mode socket, the message is sent to the address specified. If the socket is a connected-mode socket, address is ignored.

Additional control information can be passed to the stack for specific operations.

By default, sendto blocks until data is sent. If socket is set to non-blocking or times out, NSAPI_ERROR_WOULD_BLOCK is returned immediately.

Parameters

address	Remote address
data	Buffer of data to send to the host
size	Size of the buffer in bytes
control	Control data, for instance a populated nsapi_pktinfo structure.
control_size	Size of `control` in bytes.

Returns: Number of sent bytes on success, negative subclass-dependent error code on failure

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ recvfrom_control()

virtual nsapi_size_or_error_t recvfrom_control	(	SocketAddress *	address,
		void *	data,
		nsapi_size_t	size,
		nsapi_msghdr_t *	control,
		nsapi_size_t	control_size
	)

pure virtual

Receive a data from a socket.

Receives a data and stores the source address in address if address is not NULL. Returns the number of bytes written into the buffer.

If socket is connected, only packets coming from connected peer address are accepted.

Ancillary data is stored into control. The caller needs to allocate a buffer that is large enough to contain the data they want to receive, then pass the pointer in through the control member. The data will be filled into control, beginning with a header specifying what data was received. See MsgHeaderIterator for how to parse this data.

Note: recvfrom_control() is allowed write to address and data buffers even if error occurs.

By default, recvfrom blocks until a datagram is received. If socket is set to non-blocking or times out with no data, NSAPI_ERROR_WOULD_BLOCK is returned.

Parameters

address	Destination for the source address or NULL
data	Destination buffer for datagram received from the host
size	Size of the buffer in bytes
control	Caller-allocated buffer to store ancillary data.
control_size	Size of the `control` buffer that the caller has allocated.

Returns: Number of received bytes on success, negative subclass-dependent error code on failure

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ bind()

virtual nsapi_error_t bind ( const SocketAddress & address )

pure virtual

Bind a specific address to a socket.

Binding a socket specifies the address and port on which to receive data. If the IP address is zeroed, only the port is bound.

Parameters

address Local address to bind.

Returns: NSAPI_ERROR_OK on success, negative subclass-dependent error code on failure.

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ set_blocking()

virtual void set_blocking ( bool blocking )

pure virtual

Set blocking or non-blocking mode of the socket.

Initially all sockets are in blocking mode. In non-blocking mode blocking operations such as send/recv/accept return NSAPI_ERROR_WOULD_BLOCK if they cannot continue.

set_blocking(false) is equivalent to set_timeout(0) set_blocking(true) is equivalent to set_timeout(-1)

Parameters

blocking true for blocking mode, false for non-blocking mode.

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ set_timeout()

virtual void set_timeout ( int timeout )

pure virtual

Set timeout on blocking socket operations.

Initially all sockets have unbounded timeouts. NSAPI_ERROR_WOULD_BLOCK is returned if a blocking operation takes longer than the specified timeout. A timeout of 0 removes the timeout from the socket. A negative value gives the socket an unbounded timeout.

set_timeout(0) is equivalent to set_blocking(false) set_timeout(-1) is equivalent to set_blocking(true)

Parameters

timeout Timeout in milliseconds

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ sigio()

virtual void sigio ( mbed::Callback< void()> func )

pure virtual

Register a callback on state change of the socket.

The specified callback is called on state changes, such as when the socket can receive/send/accept successfully and when an error occurs. The callback may also be called spuriously without reason.

The callback may be called in an interrupt context and should not perform expensive operations such as receive/send calls.

Note! This is not intended as a replacement for a poll or attach-like asynchronous API, but rather as a building block for constructing such functionality. The exact timing of the registered function is not guaranteed and susceptible to change.

Parameters

func	Function to call on state change.

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ setsockopt()

virtual nsapi_error_t setsockopt	(	int	level,
		int	optname,
		const void *	optval,
		unsigned	optlen
	)

pure virtual

Set socket options.

setsockopt() allows an application to pass stack-specific options to the underlying stack using stack-specific level and option names, or to request generic options using levels from nsapi_socket_level_t.

For unsupported options, NSAPI_ERROR_UNSUPPORTED is returned and the socket is unmodified.

Parameters

level	Stack-specific protocol level or nsapi_socket_level_t.
optname	Level-specific option name.
optval	Option value.
optlen	Length of the option value.

Return values

NSAPI_ERROR_OK	on success.
NSAPI_ERROR_NO_SOCKET	if socket is not open.
Negative	error code on failure, see NetworkStack::setsockopt

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ getsockopt()

virtual nsapi_error_t getsockopt	(	int	level,
		int	optname,
		void *	optval,
		unsigned *	optlen
	)

pure virtual

Get socket options.

getsockopt() allows an application to retrieve stack-specific options from the underlying stack using stack-specific level and option names, or to request generic options using levels from nsapi_socket_level_t.

For unsupported options, NSAPI_ERROR_UNSUPPORTED is returned and the socket is unmodified.

Parameters

level	Stack-specific protocol level or nsapi_socket_level_t.
optname	Level-specific option name.
optval	Destination for option value.
optlen	Length of the option value.

Return values

NSAPI_ERROR_OK	on success.
NSAPI_ERROR_NO_SOCKET	if socket is not open.
Negative	error code on failure, see NetworkStack::getsockopt

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

◆ accept()

virtual Socket * accept ( nsapi_error_t * error = NULL )

pure virtual

Accepts a connection on a socket.

The server socket must be bound and set to listen for connections. On a new connection, returns connected network socket to call close() that deallocates the resources. Referencing a returned pointer after a close() call is not allowed and leads to undefined behavior.

By default, accept blocks until incoming connection occurs. If socket is set to non-blocking or times out, error is set to NSAPI_ERROR_WOULD_BLOCK.

Parameters

error Pointer to storage of the error value or NULL.

Returns: Pointer to a socket.

Implemented in CellularNonIPSocket, TCPSocket, TLSSocketWrapper, and InternetDatagramSocket.

◆ listen()

virtual nsapi_error_t listen ( int backlog = 1 )

pure virtual

Listen for incoming connections.

Marks the socket as a passive socket that can be used to accept incoming connections.

Parameters

backlog Number of pending connections that can be queued simultaneously, defaults to 1.

Returns: NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in CellularNonIPSocket, InternetDatagramSocket, TCPSocket, and TLSSocketWrapper.

◆ getpeername()

virtual nsapi_error_t getpeername ( SocketAddress * address )

pure virtual

Get the remote-end peer associated with this socket.

Copy the remote peer address to a SocketAddress structure pointed by address parameter. Socket must be connected to have a peer address associated.

Parameters

address Pointer to SocketAddress structure.

Return values

NSAPI_ERROR_OK	on success.
NSAPI_ERROR_NO_SOCKET	if socket is not connected.
NSAPI_ERROR_NO_CONNECTION	if the remote peer was not set.

Implemented in CellularNonIPSocket, InternetSocket, and TLSSocketWrapper.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

◆ ~Socket()

Member Function Documentation

◆ close()

◆ connect()

◆ send()

◆ recv()

◆ sendto()

◆ recvfrom()

◆ sendto_control()

◆ recvfrom_control()

◆ bind()

◆ set_blocking()

◆ set_timeout()

◆ sigio()

◆ setsockopt()

◆ getsockopt()

◆ accept()

◆ listen()

◆ getpeername()