Mbed OS Reference | Socket.h Source File

Go to the documentation of this file.
 /*
  * Copyright (c) 2015 ARM Limited
  * SPDX-License-Identifier: Apache-2.0
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
  *
  *     http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
 
 /** @file Socket.h Abstract Socket interface */
 /** @addtogroup netsocket
  * Mbed OS Socket API
  * @{ */
 
 #ifndef SOCKET_H
 #define SOCKET_H
 
 #include "netsocket/SocketAddress.h"
 #include "Callback.h"
 
 /** 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.
  */
 class Socket {
 public:
     /** Destroy a socket.
      *
      *  Closes socket if the socket is still open.
      */
     virtual ~Socket() = default;
 
     /** Closes the socket.
      *
      *  Closes any open connection and deallocates any memory associated
      *  with the socket. Called from destructor if socket is not closed.
      *
      *  @return         NSAPI_ERROR_OK on success.
      *                  Negative subclass-dependent error code on failure.
      */
     virtual nsapi_error_t close() = 0;
 
     /** 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.
      *
      *  @param address  The SocketAddress of the remote peer.
      *  @return         NSAPI_ERROR_OK on success.
      *                  Negative subclass-dependent error code on failure.
      */
     virtual nsapi_error_t connect(const SocketAddress &address) = 0;
 
     /** 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.
      *
      *  @param data     Buffer of data to send to the host.
      *  @param size     Size of the buffer in bytes.
      *  @return         NSAPI_ERROR_OK on success.
      *                  Negative subclass-dependent error code on failure.
      */
     virtual nsapi_size_or_error_t send(const void *data, nsapi_size_t size) = 0;
 
     /** 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.
      *
      *  @param data     Destination buffer for data received from the host.
      *  @param size     Size of the buffer in bytes.
      *  @return         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.
      */
     virtual nsapi_size_or_error_t recv(void *data, nsapi_size_t size) = 0;
 
     /** 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.
      *
      *  @param address  Remote address
      *  @param data     Buffer of data to send to the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of sent bytes on success, negative subclass-dependent error
      *                  code on failure
      */
     virtual nsapi_size_or_error_t sendto(const SocketAddress &address,
                                          const void *data, nsapi_size_t size) = 0;
 
     /** 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.
      *
      *  @param address  Destination for the source address or NULL
      *  @param data     Destination buffer for datagram received from the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of received bytes on success, negative subclass-dependent
      *                  error code on failure
      */
     virtual nsapi_size_or_error_t recvfrom(SocketAddress *address,
                                            void *data, nsapi_size_t size) = 0;
 
     /** 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.
      *
      *  @param address  Remote address
      *  @param data     Buffer of data to send to the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of sent bytes on success, negative subclass-dependent error
      *                  code on failure
      */
     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;
 
 
     /** 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.
      *
      * Additional information related to the message can be retrieved with the control 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.
      *
      *  @param address  Destination for the source address or NULL
      *  @param data     Destination buffer for datagram received from the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of received bytes on success, negative subclass-dependent
      *                  error code on failure
      */
     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;
 
     /** 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.
      *
      *  @param address  Local address to bind.
      *  @return         NSAPI_ERROR_OK on success, negative subclass-dependent error
      *                  code on failure.
      */
     virtual nsapi_error_t bind(const SocketAddress &address) = 0;
 
     /** 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)
      *
      *  @param blocking true for blocking mode, false for non-blocking mode.
      */
     virtual void set_blocking(bool blocking) = 0;
 
     /** 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)
      *
      *  @param timeout  Timeout in milliseconds
      */
     virtual void set_timeout(int timeout) = 0;
 
     /** 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.
      *
      *  @param func     Function to call on state change.
      */
     virtual void sigio(mbed::Callback<void()> func) = 0;
 
     /** 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.
      *
      *  @param level    Stack-specific protocol level or nsapi_socket_level_t.
      *  @param optname  Level-specific option name.
      *  @param optval   Option value.
      *  @param optlen   Length of the option value.
      *  @retval         NSAPI_ERROR_OK on success.
      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not open.
      *  @retval         int Negative error code on failure, see @ref NetworkStack::setsockopt.
      */
     virtual nsapi_error_t setsockopt(int level, int optname, const void *optval, unsigned optlen) = 0;
 
     /** 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.
      *
      *  @param level    Stack-specific protocol level or nsapi_socket_level_t.
      *  @param optname  Level-specific option name.
      *  @param optval   Destination for option value.
      *  @param optlen   Length of the option value.
      *  @retval         NSAPI_ERROR_OK on success.
      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not open.
      *  @retval         int Negative error code on failure, see @ref NetworkStack::getsockopt.
      */
     virtual nsapi_error_t getsockopt(int level, int optname, void *optval, unsigned *optlen) = 0;
 
     /** 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.
      *
      *  @param error      Pointer to storage of the error value or NULL.
      *  @return           Pointer to a socket.
      */
     virtual Socket *accept(nsapi_error_t *error = NULL) = 0;
 
     /** Listen for incoming connections.
      *
      *  Marks the socket as a passive socket that can be used to accept
      *  incoming connections.
      *
      *  @param backlog  Number of pending connections that can be queued
      *                  simultaneously, defaults to 1.
      *  @return         NSAPI_ERROR_OK on success, negative error code on failure.
      */
     virtual nsapi_error_t listen(int backlog = 1) = 0;
 
     /** 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.
      *
      *  @param address  Pointer to SocketAddress structure.
      *  @retval         NSAPI_ERROR_OK on success.
      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not connected.
      *  @retval         NSAPI_ERROR_NO_CONNECTION if the remote peer was not set.
      */
     virtual nsapi_error_t getpeername(SocketAddress *address) = 0;
 };
 
 
 #endif
 
 /** @}*/
Important Information for this Arm website
