text: /* NetworkStack
   * Copyright (c) 2015 ARM Limited
   *
   * 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 NETWORK_INTERFACE_H
  #define NETWORK_INTERFACE_H
  
  #include "mbed.h"
  #include "SocketAddress.h"
  
  
  /** Enum of standardized error codes 
   *
   *  Valid error codes have negative values and may
   *  be returned by any network operation.
   *
   *  @enum nsapi_error_t
   */
  enum nsapi_error_t {
      NSAPI_ERROR_WOULD_BLOCK   = -3001,     /*!< no data is not available but call is non-blocking */
      NSAPI_ERROR_UNSUPPORTED   = -3002,     /*!< unsupported functionality */
      NSAPI_ERROR_PARAMETER     = -3003,     /*!< invalid configuration */
      NSAPI_ERROR_NO_CONNECTION = -3004,     /*!< not connected to a network */
      NSAPI_ERROR_NO_SOCKET     = -3005,     /*!< socket not available for use */
      NSAPI_ERROR_NO_ADDRESS    = -3006,     /*!< IP address is not known */
      NSAPI_ERROR_NO_MEMORY     = -3007,     /*!< memory resource not available */
      NSAPI_ERROR_DNS_FAILURE   = -3008,     /*!< DNS failed to complete successfully */
      NSAPI_ERROR_DHCP_FAILURE  = -3009,     /*!< DHCP failed to complete successfully */
      NSAPI_ERROR_AUTH_FAILURE  = -3010,     /*!< connection to access point faield */
      NSAPI_ERROR_DEVICE_ERROR  = -3011      /*!< failure interfacing with the network procesor */
  };
  
  /** Enum of socket protocols
   *
   *  The socket protocol specifies a particular protocol to
   *  be used with a newly created socket. 
   *
   *  @enum nsapi_protocol_t
   */
  enum nsapi_protocol_t {
     NSAPI_TCP, /*!< Socket is of TCP type */
     NSAPI_UDP  /*!< Socket is of UDP type */
  };
  
  /*  Enum of standardized stack option levels
   *
   *  @enum nsapi_level_t
   */
  enum nsapi_level_t {
      NSAPI_STACK,  /*!< Stack option level */
      NSAPI_SOCKET  /*!< Socket option level */
  };
  
  /*  Enum of standardized stack options
   *
   *  These options may not be supported on all stacks, in which
   *  case NSAPI_ERROR_UNSUPPORTED may be returned from setsockopt.
   *
   *  @enum nsapi_option_t
   */
  enum nsapi_option_t {
      NSAPI_REUSEADDR, /*!< Allow bind to reuse local addresses */
      NSAPI_KEEPALIVE, /*!< Enables sending of keepalive messages */
      NSAPI_LINGER,    /*!< Keeps close from returning until queues empty */
      NSAPI_SNDBUF,    /*!< Sets send buffer size */
      NSAPI_RCVBUF     /*!< Sets recv buffer size */
  };
  
  
  /** NetworkStack class
   *
   *  Common interface that is shared between hardware that
   *  can connect to a network over IP. By implementing the
   *  NetworkStack, a network stack can be used as a target
   *  for instantiating network sockets.
   */
  class NetworkStack
  {
  public:
      virtual ~NetworkStack() {};
  
      /** Get the local IP address
       *
       *  @return         Null-terminated representation of the local IP address
       *                  or null if not yet connected
       */
      virtual const char *get_ip_address() = 0;
  
      /** Translates a hostname to an IP address
       *
       *  The hostname may be either a domain name or an IP address. If the
       *  hostname is an IP address, no network transactions will be performed.
       *  
       *  If no stack-specific DNS resolution is provided, the hostname
       *  will be resolve using a UDP socket on the stack. 
       *
       *  @param address  Destination for the host SocketAddress
       *  @param host     Hostname to resolve
       *  @return         0 on success, negative error code on failure
       */
      virtual int gethostbyname(SocketAddress *address, const char *host);
  
      /*  Set stack-specific stack options
       *
       *  The setstackopt allow an application to pass stack-specific hints
       *  to the underlying stack. For unsupported options,
       *  NSAPI_ERROR_UNSUPPORTED is returned and the stack is unmodified.
       *
       *  @param level    Stack-specific protocol level
       *  @param optname  Stack-specific option identifier
       *  @param optval   Option value
       *  @param optlen   Length of the option value
       *  @return         0 on success, negative error code on failure
       */    
      virtual int setstackopt(int level, int optname, const void *optval, unsigned optlen);
  
      /*  Get stack-specific stack options
       *
       *  The getstackopt allow an application to retrieve stack-specific hints
       *  from the underlying stack. For unsupported options,
       *  NSAPI_ERROR_UNSUPPORTED is returned and optval is unmodified.
       *
       *  @param level    Stack-specific protocol level
       *  @param optname  Stack-specific option identifier
       *  @param optval   Destination for option value
       *  @param optlen   Length of the option value
       *  @return         0 on success, negative error code on failure
       */    
      virtual int getstackopt(int level, int optname, void *optval, unsigned *optlen);
  
  protected:
      friend class Socket;
      friend class UDPSocket;
      friend class TCPSocket;
      friend class TCPServer;
  
      /** Opens a socket
       *
       *  Creates a network socket and stores it in the specified handle.
       *  The handle must be passed to following calls on the socket.
       *
       *  A stack may have a finite number of sockets, in this case
       *  NSAPI_ERROR_NO_SOCKET is returned if no socket is available.
       *
       *  @param handle   Destination for the handle to a newly created socket
       *  @param proto    Protocol of socket to open, NSAPI_TCP or NSAPI_UDP
       *  @return         0 on success, negative error code on failure
       */
      virtual int socket_open(void **handle, nsapi_protocol_t proto) = 0;
  
      /** Close the socket
       *
       *  Closes any open connection and deallocates any memory associated
       *  with the socket.
       *
       *  @param handle   Socket handle
       *  @return         0 on success, negative error code on failure
       */
      virtual int socket_close(void *handle) = 0;
  
      /** Bind a specific address to a socket
       *
       *  Binding a socket specifies the address and port on which to recieve
       *  data. If the IP address is zeroed, only the port is bound.
       *
       *  @param handle   Socket handle
       *  @param address  Local address to bind
       *  @return         0 on success, negative error code on failure.
       */
      virtual int socket_bind(void *handle, const SocketAddress &address) = 0;
  
      /** Listen for connections on a TCP socket
       *
       *  Marks the socket as a passive socket that can be used to accept
       *  incoming connections.
       *
       *  @param handle   Socket handle
       *  @param backlog  Number of pending connections that can be queued
       *                  simultaneously
       *  @return         0 on success, negative error code on failure
       */
      virtual int socket_listen(void *handle, int backlog) = 0;
  
      /** Connects TCP socket to a remote host
       *
       *  Initiates a connection to a remote server specified by the
       *  indicated address.
       *
       *  @param handle   Socket handle
       *  @param address  The SocketAddress of the remote host
       *  @return         0 on success, negative error code on failure
       */
      virtual int socket_connect(void *handle, const SocketAddress &address) = 0;
  
      /** Accepts a connection on a TCP socket
       *
       *  The server socket must be bound and set to listen for connections.
       *  On a new connection, creates a network socket and stores it in the
       *  specified handle. The handle must be passed to following calls on
       *  the socket.
       *
       *  A stack may have a finite number of sockets, in this case
       *  NSAPI_ERROR_NO_SOCKET is returned if no socket is available.
       *
       *  This call is non-blocking. If accept would block,
       *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
       *
       *  @param handle   Destination for a handle to the newly created sockey
       *  @param server   Socket handle to server to accept from
       *  @return         0 on success, negative error code on failure
       */
      virtual int socket_accept(void **handle, void *server) = 0;
  
      /** Send data over a TCP socket
       *
       *  The socket must be connected to a remote host. Returns the number of
       *  bytes sent from the buffer.
       *
       *  This call is non-blocking. If send would block,
       *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
       *
       *  @param handle   Socket handle
       *  @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 int socket_send(void *handle, const void *data, unsigned size) = 0;
  
      /** Receive data over a TCP socket
       *
       *  The socket must be connected to a remote host. Returns the number of
       *  bytes received into the buffer.
       *
       *  This call is non-blocking. If recv would block,
       *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
       *
       *  @param handle   Socket handle
       *  @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 error
       *                  code on failure
       */
      virtual int socket_recv(void *handle, void *data, unsigned size) = 0;
  
      /** Send a packet over a UDP socket
       *
       *  Sends data to the specified address. Returns the number of bytes
       *  sent from the buffer.
       *
       *  This call is non-blocking. If sendto would block,
       *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
       *
       *  @param handle   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 int socket_sendto(void *handle, const SocketAddress &address, const void *data, unsigned size) = 0;
  
      /** Receive a packet over a UDP socket
       *
       *  Receives data and stores the source address in address if address
       *  is not NULL. Returns the number of bytes received into the buffer.
       *
       *  This call is non-blocking. If recvfrom would block,
       *  NSAPI_ERROR_WOULD_BLOCK is returned immediately.
       *
       *  @param handle   Socket handle
       *  @param address  Destination for the source address or NULL
       *  @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 error
       *                  code on failure
       */
      virtual int socket_recvfrom(void *handle, SocketAddress *address, void *buffer, unsigned size) = 0;
  
      /** Register a callback on state change of the socket
       *
       *  The specified callback will be called on state changes such as when
       *  the socket can recv/send/accept successfully and on 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 recv/send calls.
       *
       *  @param handle   Socket handle
       *  @param callback Function to call on state change
       *  @param data     Argument to pass to callback
       */
      virtual void socket_attach(void *handle, void (*callback)(void *), void *data) = 0;
  
      /*  Set stack-specific socket options
       *
       *  The setsockopt allow an application to pass stack-specific hints
       *  to the underlying stack. For unsupported options,
       *  NSAPI_ERROR_UNSUPPORTED is returned and the socket is unmodified.
       *
       *  @param handle   Socket handle
       *  @param level    Stack-specific protocol level
       *  @param optname  Stack-specific option identifier
       *  @param optval   Option value
       *  @param optlen   Length of the option value
       *  @return         0 on success, negative error code on failure
       */    
      virtual int setsockopt(void *handle, int level, int optname, const void *optval, unsigned optlen);
  
      /*  Get stack-specific socket options
       *
       *  The getstackopt allow an application to retrieve stack-specific hints
       *  from the underlying stack. For unsupported options,
       *  NSAPI_ERROR_UNSUPPORTED is returned and optval is unmodified.
       *
       *  @param handle   Socket handle
       *  @param level    Stack-specific protocol level
       *  @param optname  Stack-specific option identifier
       *  @param optval   Destination for option value
       *  @param optlen   Length of the option value
       *  @return         0 on success, negative error code on failure
       */    
      virtual int getsockopt(void *handle, int level, int optname, void *optval, unsigned *optlen);
  };
  
  #endif
  