Mbed OS Reference | AT_CellularStack.h Source File

 /*
  * Copyright (c) 2017, Arm Limited and affiliates.
  * 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.
  */
 
 #ifndef AT_CELLULAR_STACK_H_
 #define AT_CELLULAR_STACK_H_
 
 #include "AT_CellularBase.h"
 #include "NetworkStack.h"
 
 namespace mbed {
 
 // <PDP_addr_1> and <PDP_addr_2>: each is a string type that identifies the MT in the address space applicable to the PDP.
 // The string is given as dot-separated numeric (0-255) parameter of the form:
 // a1.a2.a3.a4 for IPv4 and
 // a1.a2.a3.a4.a5.a6.a7.a8.a9.a10.a11.a12.a13.a14.a15.a16 for IPv6.
 #define PDP_IPV6_SIZE 63+1
 
 /**
  * Class AT_CellularStack.
  *
  * Implements NetworkStack and introduces interface for modem specific stack implementations.
  */
 class AT_CellularStack : public NetworkStack, public AT_CellularBase {
 
 public:
     AT_CellularStack(ATHandler &at, int cid, nsapi_ip_stack_t stack_type);
     virtual ~AT_CellularStack();
 
 public: // NetworkStack
 
     virtual const char *get_ip_address();
 protected: // NetworkStack
 
     /**
      * Modem specific socket stack initialization
      *
      *  @return 0 on success
      */
     virtual nsapi_error_t socket_stack_init();
 
     /**
       * Note: Socket_open does not actually open socket on all drivers, but that's deferred until calling `sendto`.
       * The reason is that IP stack implementations are very much modem specific and it's quite common that when a
       * socket is created (via AT commands) it must also be given remote IP address, and that is usually known
       * only when calling `sendto`.
       */
     virtual nsapi_error_t socket_open(nsapi_socket_t *handle, nsapi_protocol_t proto);
 
     virtual nsapi_error_t socket_close(nsapi_socket_t handle);
 
     virtual nsapi_error_t socket_bind(nsapi_socket_t handle, const SocketAddress &address);
 
     virtual nsapi_error_t socket_listen(nsapi_socket_t handle, int backlog);
 
     virtual nsapi_error_t socket_connect(nsapi_socket_t handle, const SocketAddress &address);
 
     virtual nsapi_error_t socket_accept(nsapi_socket_t server,
                                         nsapi_socket_t *handle, SocketAddress *address = 0);
 
     virtual nsapi_size_or_error_t socket_send(nsapi_socket_t handle,
                                               const void *data, nsapi_size_t size);
 
     virtual nsapi_size_or_error_t socket_recv(nsapi_socket_t handle,
                                               void *data, nsapi_size_t size);
 
     virtual nsapi_size_or_error_t socket_sendto(nsapi_socket_t handle, const SocketAddress &address,
                                                 const void *data, nsapi_size_t size);
 
     virtual nsapi_size_or_error_t socket_recvfrom(nsapi_socket_t handle, SocketAddress *address,
                                                   void *buffer, nsapi_size_t size);
 
     virtual void socket_attach(nsapi_socket_t handle, void (*callback)(void *), void *data);
 
 protected:
 
     class CellularSocket {
     public:
         CellularSocket() :
             id(-1),
             connected(false),
             proto(NSAPI_UDP),
             remoteAddress("", 0),
             localAddress("", 0),
             _cb(NULL),
             _data(NULL),
             closed(false),
             started(false),
             tx_ready(false),
             rx_avail(false),
             pending_bytes(0)
         {
         }
         // Socket identifier, generally it will be the socket ID assigned by the
         // modem. In a few special cases, modems may take that as an input argument.
         int id;
         // Being connected means remote ip address and port are set
         bool connected;
         nsapi_protocol_t proto;
         SocketAddress remoteAddress;
         SocketAddress localAddress;
         void (*_cb)(void *);
         void *_data;
         bool closed; // socket has been closed by a peer
         bool started; // socket has been opened on modem stack
         bool tx_ready; // socket is ready for sending on modem stack
         bool rx_avail; // socket has data for reading on modem stack
         nsapi_size_t pending_bytes; // The number of received bytes pending
     };
 
     /**
     * Gets maximum number of sockets modem supports
     */
     virtual int get_max_socket_count() = 0;
 
     /**
     * Checks if modem supports the given protocol
     *
     * @param protocol   Protocol type
     */
     virtual bool is_protocol_supported(nsapi_protocol_t protocol) = 0;
 
     /**
     * Implements modem specific AT command set for socket closing
     *
     * @param sock_id   Socket id
     */
     virtual nsapi_error_t socket_close_impl(int sock_id) = 0;
 
     /**
     * Implements modem specific AT command set for creating socket
     *
     * @param socket   Cellular socket handle
     */
     virtual nsapi_error_t create_socket_impl(CellularSocket *socket) = 0;
 
     /**
     * Implements modem specific AT command set for sending data
     *
     * @param socket   Cellular socket handle
     * @param address  The SocketAddress of the remote host
     * @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 error
     *                 code on failure
     */
     virtual nsapi_size_or_error_t socket_sendto_impl(CellularSocket *socket, const SocketAddress &address,
                                                      const void *data, nsapi_size_t size) = 0;
 
     /**
      *  Implements modem specific AT command set for receiving data
      *
      *  @param socket   Socket handle
      *  @param address  Destination for the source address or NULL
      *  @param buffer   Destination buffer for data received from the host
      *  @param size     Size of the buffer in bytes
      *  @return         Number of received bytes on success, negative error
      *                  code on failure
      */
     virtual nsapi_size_or_error_t socket_recvfrom_impl(CellularSocket *socket, SocketAddress *address,
                                                        void *buffer, nsapi_size_t size) = 0;
 
     /**
      *  Find the socket handle based on the index of the socket construct
      *  in the socket container. Please note that this index may or may not be
      *  the socket id. The actual meaning of this index depends upon the modem
      *  being used.
      *
      *  @param index    Index of the socket construct in the container
      *  @return         Socket handle, NULL on error
      */
     CellularSocket *find_socket(int index);
 
     /**
      *  Find the index of the given CellularSocket handle. This index may or may
      *  not be the socket id. The actual meaning of this index depends upon the modem
      *  being used.
      */
     int find_socket_index(nsapi_socket_t handle);
 
     // socket container
     CellularSocket **_socket;
 
     // number of socket slots allocated in socket container
     int _socket_count;
 
     // IP address
     char _ip[PDP_IPV6_SIZE];
 
     // PDP context id
     int _cid;
 
     // stack type from PDP context
     nsapi_ip_stack_t _stack_type;
 
 private:
 
     int get_socket_index_by_port(uint16_t port);
 
     // mutex for write/read to a _socket array, needed when multiple threads may open sockets simultaneously
     PlatformMutex _socket_mutex;
 };
 
 } // namespace mbed
 
 #endif // AT_CELLULAR_STACK_H_
Important Information for this Arm website
