Socket.h

00001 /*
00002  * Copyright (c) 2015 ARM Limited
00003  *
00004  * Licensed under the Apache License, Version 2.0 (the "License");
00005  * you may not use this file except in compliance with the License.
00006  * You may obtain a copy of the License at
00007  *
00008  *     http://www.apache.org/licenses/LICENSE-2.0
00009  *
00010  * Unless required by applicable law or agreed to in writing, software
00011  * distributed under the License is distributed on an "AS IS" BASIS,
00012  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013  * See the License for the specific language governing permissions and
00014  * limitations under the License.
00015  */
00016 
00017 /** @file Socket.h Abstract Socket interface */
00018 /** @addtogroup netsocket
00019  * Mbed OS Socket API
00020  * @{ */
00021 
00022 #ifndef SOCKET_H
00023 #define SOCKET_H
00024 
00025 #include "netsocket/SocketAddress.h"
00026 #include "Callback.h"
00027 
00028 /** Socket interface.
00029  *
00030  * This class defines the Mbed OS Socket API.
00031  * Socket is an abstract interface for communicating with remote endpoints.
00032  *
00033  * This API is intended for applications and libraries instead of
00034  * protocol-specific implementations. For example, TCPSocket
00035  * and UDPSocket are implementations of the Socket interface.
00036  * Socket API is intentionally not protocol-specific, and allows all protocol
00037  * to provide the same API regardless of the underlying transport mechanism.
00038  */
00039 class Socket {
00040 public:
00041     /** Destroy a socket.
00042      *
00043      *  Closes socket if the socket is still open.
00044      */
00045     virtual ~Socket() {}
00046 
00047     /** Closes the socket.
00048      *
00049      *  Closes any open connection and deallocates any memory associated
00050      *  with the socket. Called from destructor if socket is not closed.
00051      *
00052      *  @return         NSAPI_ERROR_OK on success.
00053      *                  Negative subclass-dependent error code on failure.
00054      */
00055     virtual nsapi_error_t close() = 0;
00056 
00057     /** Connects socket to a remote address.
00058      *
00059      *  Attempts to make connection on connection-mode protocol or set or reset
00060      *  the peer address on connectionless protocol.
00061      *
00062      *  Connectionless protocols also use the connected address to filter
00063      *  incoming packets for recv() and recvfrom() calls.
00064      *
00065      *  To reset the peer address, there must be zero initialized(default constructor) SocketAddress
00066      *  objects in the address parameter.
00067      *
00068      *  @note If connect() fails it is recommended to close the Socket and create
00069      *  a new one before attempting to reconnect.
00070      *
00071      *  @param address  The SocketAddress of the remote peer.
00072      *  @return         NSAPI_ERROR_OK on success.
00073      *                  Negative subclass-dependent error code on failure.
00074      */
00075     virtual nsapi_error_t connect(const SocketAddress &address) = 0;
00076 
00077     /** Send data on a socket
00078      *
00079      *  The socket must be connected to a remote host before send() call.
00080      *  Returns the number of bytes sent from the buffer.
00081      *  In case of connectionless socket, sends data to pre-specified remote.
00082      *
00083      *  By default, send blocks until all data is sent. If socket is set to
00084      *  non-blocking or times out, a partial amount can be written.
00085      *  NSAPI_ERROR_WOULD_BLOCK is returned if no data was written.
00086      *
00087      *  @param data     Buffer of data to send to the host.
00088      *  @param size     Size of the buffer in bytes.
00089      *  @return         NSAPI_ERROR_OK on success.
00090      *                  Negative subclass-dependent error code on failure.
00091      */
00092     virtual nsapi_size_or_error_t send(const void *data, nsapi_size_t size) = 0;
00093 
00094     /** Receive data from a socket.
00095      *
00096      *  Receive data from connected socket, or in the case of connectionless socket,
00097      *  equivalent to calling recvfrom(NULL, data, size).
00098      *
00099      *  If socket is connected, only packets coming from connected peer address
00100      *  are accepted.
00101      *
00102      *  @note recv() is allowed write to data buffer even if an error occurs.
00103      *
00104      *  By default, recv blocks until some data is received. If socket is set to
00105      *  non-blocking or times out, NSAPI_ERROR_WOULD_BLOCK can be returned to
00106      *  indicate no data.
00107      *
00108      *  @param data     Destination buffer for data received from the host.
00109      *  @param size     Size of the buffer in bytes.
00110      *  @return         Number of received bytes on success, negative, subclass-dependent
00111      *                  error code on failure. If no data is available to be received
00112      *                  and the peer has performed an orderly shutdown,
00113      *                  recv() returns 0.
00114      */
00115     virtual nsapi_size_or_error_t recv(void *data, nsapi_size_t size) = 0;
00116 
00117     /** Send a message on a socket.
00118      *
00119      * The sendto() function sends a message through a connection-mode or connectionless-mode socket.
00120      * If the socket is a connectionless-mode socket, the message is sent to the address specified.
00121      * If the socket is a connected-mode socket, address is ignored.
00122      *
00123      * By default, sendto blocks until data is sent. If socket is set to
00124      * non-blocking or times out, NSAPI_ERROR_WOULD_BLOCK is returned
00125      * immediately.
00126      *
00127      *  @param address  Remote address
00128      *  @param data     Buffer of data to send to the host
00129      *  @param size     Size of the buffer in bytes
00130      *  @return         Number of sent bytes on success, negative subclass-dependent error
00131      *                  code on failure
00132      */
00133     virtual nsapi_size_or_error_t sendto(const SocketAddress &address,
00134                                          const void *data, nsapi_size_t size) = 0;
00135 
00136     /** Receive a data from a socket
00137      *
00138      *  Receives a data and stores the source address in address if address
00139      *  is not NULL. Returns the number of bytes written into the buffer.
00140      *
00141      *  If socket is connected, only packets coming from connected peer address
00142      *  are accepted.
00143      *
00144      *  @note recvfrom() is allowed write to address and data buffers even if error occurs.
00145      *
00146      *  By default, recvfrom blocks until a datagram is received. If socket is set to
00147      *  non-blocking or times out with no data, NSAPI_ERROR_WOULD_BLOCK
00148      *  is returned.
00149      *
00150      *  @param address  Destination for the source address or NULL
00151      *  @param data     Destination buffer for datagram received from the host
00152      *  @param size     Size of the buffer in bytes
00153      *  @return         Number of received bytes on success, negative subclass-dependent
00154      *                  error code on failure
00155      */
00156     virtual nsapi_size_or_error_t recvfrom(SocketAddress *address,
00157                                            void *data, nsapi_size_t size) = 0;
00158 
00159     /** Bind a specific address to a socket.
00160      *
00161      *  Binding a socket specifies the address and port on which to receive
00162      *  data. If the IP address is zeroed, only the port is bound.
00163      *
00164      *  @param address  Local address to bind.
00165      *  @return         NSAPI_ERROR_OK on success, negative subclass-dependent error
00166      *                  code on failure.
00167      */
00168     virtual nsapi_error_t bind(const SocketAddress &address) = 0;
00169 
00170     /** Set blocking or non-blocking mode of the socket.
00171      *
00172      *  Initially all sockets are in blocking mode. In non-blocking mode
00173      *  blocking operations such as send/recv/accept return
00174      *  NSAPI_ERROR_WOULD_BLOCK if they cannot continue.
00175      *
00176      *  set_blocking(false) is equivalent to set_timeout(0)
00177      *  set_blocking(true) is equivalent to set_timeout(-1)
00178      *
00179      *  @param blocking true for blocking mode, false for non-blocking mode.
00180      */
00181     virtual void set_blocking(bool blocking) = 0;
00182 
00183     /** Set timeout on blocking socket operations.
00184      *
00185      *  Initially all sockets have unbounded timeouts. NSAPI_ERROR_WOULD_BLOCK
00186      *  is returned if a blocking operation takes longer than the specified
00187      *  timeout. A timeout of 0 removes the timeout from the socket. A negative
00188      *  value gives the socket an unbounded timeout.
00189      *
00190      *  set_timeout(0) is equivalent to set_blocking(false)
00191      *  set_timeout(-1) is equivalent to set_blocking(true)
00192      *
00193      *  @param timeout  Timeout in milliseconds
00194      */
00195     virtual void set_timeout(int timeout) = 0;
00196 
00197     /** Register a callback on state change of the socket.
00198      *
00199      *  The specified callback is called on state changes, such as when
00200      *  the socket can receive/send/accept successfully and when an error
00201      *  occurs. The callback may also be called spuriously without reason.
00202      *
00203      *  The callback may be called in an interrupt context and should not
00204      *  perform expensive operations such as receive/send calls.
00205      *
00206      *  Note! This is not intended as a replacement for a poll or attach-like
00207      *  asynchronous API, but rather as a building block for constructing
00208      *  such functionality. The exact timing of the registered function
00209      *  is not guaranteed and susceptible to change.
00210      *
00211      *  @param func     Function to call on state change.
00212      */
00213     virtual void sigio(mbed::Callback<void()> func) = 0;
00214 
00215     /** Set socket options.
00216      *
00217      *  setsockopt() allows an application to pass stack-specific options
00218      *  to the underlying stack using stack-specific level and option names,
00219      *  or to request generic options using levels from nsapi_socket_level_t.
00220      *
00221      *  For unsupported options, NSAPI_ERROR_UNSUPPORTED is returned
00222      *  and the socket is unmodified.
00223      *
00224      *  @param level    Stack-specific protocol level or nsapi_socket_level_t.
00225      *  @param optname  Level-specific option name.
00226      *  @param optval   Option value.
00227      *  @param optlen   Length of the option value.
00228      *  @retval         NSAPI_ERROR_OK on success.
00229      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not open.
00230      *  @retval         int Negative error code on failure, see @ref NetworkStack::setsockopt.
00231      */
00232     virtual nsapi_error_t setsockopt(int level, int optname, const void *optval, unsigned optlen) = 0;
00233 
00234     /** Get socket options.
00235      *
00236      *  getsockopt() allows an application to retrieve stack-specific options
00237      *  from the underlying stack using stack-specific level and option names,
00238      *  or to request generic options using levels from nsapi_socket_level_t.
00239      *
00240      *  For unsupported options, NSAPI_ERROR_UNSUPPORTED is returned
00241      *  and the socket is unmodified.
00242      *
00243      *  @param level    Stack-specific protocol level or nsapi_socket_level_t.
00244      *  @param optname  Level-specific option name.
00245      *  @param optval   Destination for option value.
00246      *  @param optlen   Length of the option value.
00247      *  @retval         NSAPI_ERROR_OK on success.
00248      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not open.
00249      *  @retval         int Negative error code on failure, see @ref NetworkStack::getsockopt.
00250      */
00251     virtual nsapi_error_t getsockopt(int level, int optname, void *optval, unsigned *optlen) = 0;
00252 
00253     /** Accepts a connection on a socket.
00254      *
00255      *  The server socket must be bound and set to listen for connections.
00256      *  On a new connection, returns connected network socket to call close()
00257      *  that deallocates the resources. Referencing a returned pointer after a close()
00258      *  call is not allowed and leads to undefined behavior.
00259      *
00260      *  By default, accept blocks until incoming connection occurs. If socket is set to
00261      *  non-blocking or times out, error is set to NSAPI_ERROR_WOULD_BLOCK.
00262      *
00263      *  @param error      Pointer to storage of the error value or NULL.
00264      *  @return           Pointer to a socket.
00265      */
00266     virtual Socket *accept(nsapi_error_t *error = NULL) = 0;
00267 
00268     /** Listen for incoming connections.
00269      *
00270      *  Marks the socket as a passive socket that can be used to accept
00271      *  incoming connections.
00272      *
00273      *  @param backlog  Number of pending connections that can be queued
00274      *                  simultaneously, defaults to 1.
00275      *  @return         NSAPI_ERROR_OK on success, negative error code on failure.
00276      */
00277     virtual nsapi_error_t listen(int backlog = 1) = 0;
00278 
00279     /** Get the remote-end peer associated with this socket.
00280      *
00281      * Copy the remote peer address to a SocketAddress structure pointed by
00282      * address parameter. Socket must be connected to have a peer address
00283      * associated.
00284      *
00285      *  @param address  Pointer to SocketAddress structure.
00286      *  @retval         NSAPI_ERROR_OK on success.
00287      *  @retval         NSAPI_ERROR_NO_SOCKET if socket is not connected.
00288      *  @retval         NSAPI_ERROR_NO_CONNECTION if the remote peer was not set.
00289      */
00290     virtual nsapi_error_t getpeername(SocketAddress *address) = 0;
00291 };
00292 
00293 
00294 #endif
00295 
00296 /** @}*/