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Public Member Functions
Socket Class Referenceabstract

Socket interface. More...

#include <Socket.h>

Inheritance diagram for Socket:
InternetSocket TLSSocketWrapper TCPSocket UDPSocket DTLSSocketWrapper TLSSocket TCPServer DTLSSocket

Public Member Functions

virtual ~Socket ()
 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_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 Socketaccept (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 39 of file Socket.h.

Constructor & Destructor Documentation

virtual ~Socket ( )
virtual

Destroy a socket.

Closes socket if the socket is still open.

Definition at line 45 of file Socket.h.

Member Function Documentation

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
errorPointer to storage of the error value or NULL.
Returns
Pointer to a socket.

Implemented in TCPSocket, UDPSocket, and TLSSocketWrapper.

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
addressLocal address to bind.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TLSSocketWrapper, and InternetSocket.

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 error code on failure

Implemented in TLSSocketWrapper, and InternetSocket.

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.

Parameters
addressThe SocketAddress of the remote peer.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TLSSocketWrapper, UDPSocket, and TCPSocket.

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
addressPointer to SocketAddress structure.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TLSSocketWrapper, and InternetSocket.

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
levelStack-specific protocol level or nsapi_socket_level_t.
optnameLevel-specific option name.
optvalDestination for option value.
optlenLength of the option value.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TLSSocketWrapper, and InternetSocket.

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
backlogNumber of pending connections that can be queued simultaneously, defaults to 1.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TCPSocket, UDPSocket, and TLSSocketWrapper.

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
dataDestination buffer for data received from the host.
sizeSize of the buffer in bytes.
Returns
Number of received bytes on success, negative 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 UDPSocket, TLSSocketWrapper, and TCPSocket.

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
addressDestination for the source address or NULL
dataDestination buffer for datagram received from the host
sizeSize of the buffer in bytes
Returns
Number of received bytes on success, negative error code on failure

Implemented in TCPSocket, TLSSocketWrapper, and UDPSocket.

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
dataBuffer of data to send to the host.
sizeSize of the buffer in bytes.
Returns
Number of sent bytes on success, negative error code on failure.

Implemented in UDPSocket, TLSSocketWrapper, and TCPSocket.

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
addressRemote address
dataBuffer of data to send to the host
sizeSize of the buffer in bytes
Returns
Number of sent bytes on success, negative error code on failure

Implemented in TCPSocket, TLSSocketWrapper, and UDPSocket.

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

Implemented in TLSSocketWrapper, and InternetSocket.

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
timeoutTimeout in milliseconds

Implemented in TLSSocketWrapper, and InternetSocket.

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
levelStack-specific protocol level or nsapi_socket_level_t.
optnameLevel-specific option name.
optvalOption value.
optlenLength of the option value.
Returns
NSAPI_ERROR_OK on success, negative error code on failure.

Implemented in TLSSocketWrapper, and InternetSocket.

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
funcFunction to call on state change.

Implemented in TLSSocketWrapper, and InternetSocket.

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