text: /***************************************************************************//**
   * # License
   *
   * The licensor of this software is Silicon Laboratories Inc. Your use of this
   * software is governed by the terms of Silicon Labs Master Software License
   * Agreement (MSLA) available at
   * www.silabs.com/about-us/legal/master-software-license-agreement. This
   * software is Third Party Software licensed by Silicon Labs from a third party
   * and is governed by the sections of the MSLA applicable to Third Party
   * Software and the additional terms set forth below.
   *
   ******************************************************************************/
  /**
   * \file net_sockets.h
   *
   * \brief Network communication functions
   */
  /*
   *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
   *  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.
   *
   *  This file is part of mbed TLS (https://tls.mbed.org)
   */
  #ifndef MBEDTLS_NET_SOCKETS_H
  #define MBEDTLS_NET_SOCKETS_H
  
  #if !defined(MBEDTLS_CONFIG_FILE)
  #include "config.h"
  #else
  #include MBEDTLS_CONFIG_FILE
  #endif
  
  #include "ssl.h"
  
  #include <stddef.h>
  #include <stdint.h>
  
  #define MBEDTLS_ERR_NET_SOCKET_FAILED                     -0x0042  /**< Failed to open a socket. */
  #define MBEDTLS_ERR_NET_CONNECT_FAILED                    -0x0044  /**< The connection to the given server / port failed. */
  #define MBEDTLS_ERR_NET_BIND_FAILED                       -0x0046  /**< Binding of the socket failed. */
  #define MBEDTLS_ERR_NET_LISTEN_FAILED                     -0x0048  /**< Could not listen on the socket. */
  #define MBEDTLS_ERR_NET_ACCEPT_FAILED                     -0x004A  /**< Could not accept the incoming connection. */
  #define MBEDTLS_ERR_NET_RECV_FAILED                       -0x004C  /**< Reading information from the socket failed. */
  #define MBEDTLS_ERR_NET_SEND_FAILED                       -0x004E  /**< Sending information through the socket failed. */
  #define MBEDTLS_ERR_NET_CONN_RESET                        -0x0050  /**< Connection was reset by peer. */
  #define MBEDTLS_ERR_NET_UNKNOWN_HOST                      -0x0052  /**< Failed to get an IP address for the given hostname. */
  #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL                  -0x0043  /**< Buffer is too small to hold the data. */
  #define MBEDTLS_ERR_NET_INVALID_CONTEXT                   -0x0045  /**< The context is invalid, eg because it was free()ed. */
  
  #define MBEDTLS_NET_LISTEN_BACKLOG         10 /**< The backlog that listen() should use. */
  
  #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */
  #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */
  
  #ifdef __cplusplus
  extern "C" {
  #endif
  
  /**
   * Wrapper type for sockets.
   *
   * Currently backed by just a file descriptor, but might be more in the future
   * (eg two file descriptors for combined IPv4 + IPv6 support, or additional
   * structures for hand-made UDP demultiplexing).
   */
  typedef struct
  {
      int fd;             /**< The underlying file descriptor                 */
  }
  mbedtls_net_context;
  
  /**
   * \brief          Initialize a context
   *                 Just makes the context ready to be used or freed safely.
   *
   * \param ctx      Context to initialize
   */
  void mbedtls_net_init( mbedtls_net_context *ctx );
  
  /**
   * \brief          Initiate a connection with host:port in the given protocol
   *
   * \param ctx      Socket to use
   * \param host     Host to connect to
   * \param port     Port to connect to
   * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
   *
   * \return         0 if successful, or one of:
   *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
   *                      MBEDTLS_ERR_NET_UNKNOWN_HOST,
   *                      MBEDTLS_ERR_NET_CONNECT_FAILED
   *
   * \note           Sets the socket in connected mode even with UDP.
   */
  int mbedtls_net_connect( mbedtls_net_context *ctx, const char *host, const char *port, int proto );
  
  /**
   * \brief          Create a receiving socket on bind_ip:port in the chosen
   *                 protocol. If bind_ip == NULL, all interfaces are bound.
   *
   * \param ctx      Socket to use
   * \param bind_ip  IP to bind to, can be NULL
   * \param port     Port number to use
   * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
   *
   * \return         0 if successful, or one of:
   *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
   *                      MBEDTLS_ERR_NET_BIND_FAILED,
   *                      MBEDTLS_ERR_NET_LISTEN_FAILED
   *
   * \note           Regardless of the protocol, opens the sockets and binds it.
   *                 In addition, make the socket listening if protocol is TCP.
   */
  int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto );
  
  /**
   * \brief           Accept a connection from a remote client
   *
   * \param bind_ctx  Relevant socket
   * \param client_ctx Will contain the connected client socket
   * \param client_ip Will contain the client IP address, can be NULL
   * \param buf_size  Size of the client_ip buffer
   * \param ip_len    Will receive the size of the client IP written,
   *                  can be NULL if client_ip is null
   *
   * \return          0 if successful, or
   *                  MBEDTLS_ERR_NET_ACCEPT_FAILED, or
   *                  MBEDTLS_ERR_NET_BUFFER_TOO_SMALL if buf_size is too small,
   *                  MBEDTLS_ERR_SSL_WANT_READ if bind_fd was set to
   *                  non-blocking and accept() would block.
   */
  int mbedtls_net_accept( mbedtls_net_context *bind_ctx,
                          mbedtls_net_context *client_ctx,
                          void *client_ip, size_t buf_size, size_t *ip_len );
  
  /**
   * \brief          Set the socket blocking
   *
   * \param ctx      Socket to set
   *
   * \return         0 if successful, or a non-zero error code
   */
  int mbedtls_net_set_block( mbedtls_net_context *ctx );
  
  /**
   * \brief          Set the socket non-blocking
   *
   * \param ctx      Socket to set
   *
   * \return         0 if successful, or a non-zero error code
   */
  int mbedtls_net_set_nonblock( mbedtls_net_context *ctx );
  
  /**
   * \brief          Portable usleep helper
   *
   * \param usec     Amount of microseconds to sleep
   *
   * \note           Real amount of time slept will not be less than
   *                 select()'s timeout granularity (typically, 10ms).
   */
  void mbedtls_net_usleep( unsigned long usec );
  
  /**
   * \brief          Read at most 'len' characters. If no error occurs,
   *                 the actual amount read is returned.
   *
   * \param ctx      Socket
   * \param buf      The buffer to write to
   * \param len      Maximum length of the buffer
   *
   * \return         the number of bytes received,
   *                 or a non-zero error code; with a non-blocking socket,
   *                 MBEDTLS_ERR_SSL_WANT_READ indicates read() would block.
   */
  int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len );
  
  /**
   * \brief          Write at most 'len' characters. If no error occurs,
   *                 the actual amount read is returned.
   *
   * \param ctx      Socket
   * \param buf      The buffer to read from
   * \param len      The length of the buffer
   *
   * \return         the number of bytes sent,
   *                 or a non-zero error code; with a non-blocking socket,
   *                 MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block.
   */
  int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len );
  
  /**
   * \brief          Read at most 'len' characters, blocking for at most
   *                 'timeout' seconds. If no error occurs, the actual amount
   *                 read is returned.
   *
   * \param ctx      Socket
   * \param buf      The buffer to write to
   * \param len      Maximum length of the buffer
   * \param timeout  Maximum number of milliseconds to wait for data
   *                 0 means no timeout (wait forever)
   *
   * \return         the number of bytes received,
   *                 or a non-zero error code:
   *                 MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
   *                 MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
   *
   * \note           This function will block (until data becomes available or
   *                 timeout is reached) even if the socket is set to
   *                 non-blocking. Handling timeouts with non-blocking reads
   *                 requires a different strategy.
   */
  int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len,
                        uint32_t timeout );
  
  /**
   * \brief          Gracefully shutdown the connection and free associated data
   *
   * \param ctx      The context to free
   */
  void mbedtls_net_free( mbedtls_net_context *ctx );
  
  #ifdef __cplusplus
  }
  #endif
  
  #endif /* net_sockets.h */
  