net_sockets.h

00001 /**
00002  * \file net_sockets.h
00003  *
00004  * \brief   Network sockets abstraction layer to integrate Mbed TLS into a
00005  *          BSD-style sockets API.
00006  *
00007  *          The network sockets module provides an example integration of the
00008  *          Mbed TLS library into a BSD sockets implementation. The module is
00009  *          intended to be an example of how Mbed TLS can be integrated into a
00010  *          networking stack, as well as to be Mbed TLS's network integration
00011  *          for its supported platforms.
00012  *
00013  *          The module is intended only to be used with the Mbed TLS library and
00014  *          is not intended to be used by third party application software
00015  *          directly.
00016  *
00017  *          The supported platforms are as follows:
00018  *              * Microsoft Windows and Windows CE
00019  *              * POSIX/Unix platforms including Linux, OS X
00020  *
00021  */
00022 /*
00023  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
00024  *  SPDX-License-Identifier: Apache-2.0
00025  *
00026  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
00027  *  not use this file except in compliance with the License.
00028  *  You may obtain a copy of the License at
00029  *
00030  *  http://www.apache.org/licenses/LICENSE-2.0
00031  *
00032  *  Unless required by applicable law or agreed to in writing, software
00033  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
00034  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00035  *  See the License for the specific language governing permissions and
00036  *  limitations under the License.
00037  *
00038  *  This file is part of mbed TLS (https://tls.mbed.org)
00039  */
00040 #ifndef MBEDTLS_NET_SOCKETS_H
00041 #define MBEDTLS_NET_SOCKETS_H
00042 
00043 #if !defined(MBEDTLS_CONFIG_FILE)
00044 #include "mbedtls/config.h"
00045 #else
00046 #include MBEDTLS_CONFIG_FILE
00047 #endif
00048 
00049 #include "mbedtls/ssl.h"
00050 
00051 #include <stddef.h>
00052 #include <stdint.h>
00053 
00054 #define MBEDTLS_ERR_NET_SOCKET_FAILED                     -0x0042  /**< Failed to open a socket. */
00055 #define MBEDTLS_ERR_NET_CONNECT_FAILED                    -0x0044  /**< The connection to the given server / port failed. */
00056 #define MBEDTLS_ERR_NET_BIND_FAILED                       -0x0046  /**< Binding of the socket failed. */
00057 #define MBEDTLS_ERR_NET_LISTEN_FAILED                     -0x0048  /**< Could not listen on the socket. */
00058 #define MBEDTLS_ERR_NET_ACCEPT_FAILED                     -0x004A  /**< Could not accept the incoming connection. */
00059 #define MBEDTLS_ERR_NET_RECV_FAILED                       -0x004C  /**< Reading information from the socket failed. */
00060 #define MBEDTLS_ERR_NET_SEND_FAILED                       -0x004E  /**< Sending information through the socket failed. */
00061 #define MBEDTLS_ERR_NET_CONN_RESET                        -0x0050  /**< Connection was reset by peer. */
00062 #define MBEDTLS_ERR_NET_UNKNOWN_HOST                      -0x0052  /**< Failed to get an IP address for the given hostname. */
00063 #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL                  -0x0043  /**< Buffer is too small to hold the data. */
00064 #define MBEDTLS_ERR_NET_INVALID_CONTEXT                   -0x0045  /**< The context is invalid, eg because it was free()ed. */
00065 #define MBEDTLS_ERR_NET_POLL_FAILED                       -0x0047  /**< Polling the net context failed. */
00066 #define MBEDTLS_ERR_NET_BAD_INPUT_DATA                    -0x0049  /**< Input invalid. */
00067 
00068 #define MBEDTLS_NET_LISTEN_BACKLOG         10 /**< The backlog that listen() should use. */
00069 
00070 #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */
00071 #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */
00072 
00073 #define MBEDTLS_NET_POLL_READ  1 /**< Used in \c mbedtls_net_poll to check for pending data  */
00074 #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */
00075 
00076 #ifdef __cplusplus
00077 extern "C" {
00078 #endif
00079 
00080 /**
00081  * Wrapper type for sockets.
00082  *
00083  * Currently backed by just a file descriptor, but might be more in the future
00084  * (eg two file descriptors for combined IPv4 + IPv6 support, or additional
00085  * structures for hand-made UDP demultiplexing).
00086  */
00087 typedef struct mbedtls_net_context
00088 {
00089     int fd;             /**< The underlying file descriptor                 */
00090 }
00091 mbedtls_net_context;
00092 
00093 /**
00094  * \brief          Initialize a context
00095  *                 Just makes the context ready to be used or freed safely.
00096  *
00097  * \param ctx      Context to initialize
00098  */
00099 void mbedtls_net_init( mbedtls_net_context *ctx );
00100 
00101 /**
00102  * \brief          Initiate a connection with host:port in the given protocol
00103  *
00104  * \param ctx      Socket to use
00105  * \param host     Host to connect to
00106  * \param port     Port to connect to
00107  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
00108  *
00109  * \return         0 if successful, or one of:
00110  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
00111  *                      MBEDTLS_ERR_NET_UNKNOWN_HOST,
00112  *                      MBEDTLS_ERR_NET_CONNECT_FAILED
00113  *
00114  * \note           Sets the socket in connected mode even with UDP.
00115  */
00116 int mbedtls_net_connect( mbedtls_net_context *ctx, const char *host, const char *port, int proto );
00117 
00118 /**
00119  * \brief          Create a receiving socket on bind_ip:port in the chosen
00120  *                 protocol. If bind_ip == NULL, all interfaces are bound.
00121  *
00122  * \param ctx      Socket to use
00123  * \param bind_ip  IP to bind to, can be NULL
00124  * \param port     Port number to use
00125  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
00126  *
00127  * \return         0 if successful, or one of:
00128  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
00129  *                      MBEDTLS_ERR_NET_BIND_FAILED,
00130  *                      MBEDTLS_ERR_NET_LISTEN_FAILED
00131  *
00132  * \note           Regardless of the protocol, opens the sockets and binds it.
00133  *                 In addition, make the socket listening if protocol is TCP.
00134  */
00135 int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto );
00136 
00137 /**
00138  * \brief           Accept a connection from a remote client
00139  *
00140  * \param bind_ctx  Relevant socket
00141  * \param client_ctx Will contain the connected client socket
00142  * \param client_ip Will contain the client IP address, can be NULL
00143  * \param buf_size  Size of the client_ip buffer
00144  * \param ip_len    Will receive the size of the client IP written,
00145  *                  can be NULL if client_ip is null
00146  *
00147  * \return          0 if successful, or
00148  *                  MBEDTLS_ERR_NET_ACCEPT_FAILED, or
00149  *                  MBEDTLS_ERR_NET_BUFFER_TOO_SMALL if buf_size is too small,
00150  *                  MBEDTLS_ERR_SSL_WANT_READ if bind_fd was set to
00151  *                  non-blocking and accept() would block.
00152  */
00153 int mbedtls_net_accept( mbedtls_net_context *bind_ctx,
00154                         mbedtls_net_context *client_ctx,
00155                         void *client_ip, size_t buf_size, size_t *ip_len );
00156 
00157 /**
00158  * \brief          Check and wait for the context to be ready for read/write
00159  *
00160  * \param ctx      Socket to check
00161  * \param rw       Bitflag composed of MBEDTLS_NET_POLL_READ and
00162  *                 MBEDTLS_NET_POLL_WRITE specifying the events
00163  *                 to wait for:
00164  *                 - If MBEDTLS_NET_POLL_READ is set, the function
00165  *                   will return as soon as the net context is available
00166  *                   for reading.
00167  *                 - If MBEDTLS_NET_POLL_WRITE is set, the function
00168  *                   will return as soon as the net context is available
00169  *                   for writing.
00170  * \param timeout  Maximal amount of time to wait before returning,
00171  *                 in milliseconds. If \c timeout is zero, the
00172  *                 function returns immediately. If \c timeout is
00173  *                 -1u, the function blocks potentially indefinitely.
00174  *
00175  * \return         Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE
00176  *                 on success or timeout, or a negative return code otherwise.
00177  */
00178 int mbedtls_net_poll( mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout );
00179 
00180 /**
00181  * \brief          Set the socket blocking
00182  *
00183  * \param ctx      Socket to set
00184  *
00185  * \return         0 if successful, or a non-zero error code
00186  */
00187 int mbedtls_net_set_block( mbedtls_net_context *ctx );
00188 
00189 /**
00190  * \brief          Set the socket non-blocking
00191  *
00192  * \param ctx      Socket to set
00193  *
00194  * \return         0 if successful, or a non-zero error code
00195  */
00196 int mbedtls_net_set_nonblock( mbedtls_net_context *ctx );
00197 
00198 /**
00199  * \brief          Portable usleep helper
00200  *
00201  * \param usec     Amount of microseconds to sleep
00202  *
00203  * \note           Real amount of time slept will not be less than
00204  *                 select()'s timeout granularity (typically, 10ms).
00205  */
00206 void mbedtls_net_usleep( unsigned long usec );
00207 
00208 /**
00209  * \brief          Read at most 'len' characters. If no error occurs,
00210  *                 the actual amount read is returned.
00211  *
00212  * \param ctx      Socket
00213  * \param buf      The buffer to write to
00214  * \param len      Maximum length of the buffer
00215  *
00216  * \return         the number of bytes received,
00217  *                 or a non-zero error code; with a non-blocking socket,
00218  *                 MBEDTLS_ERR_SSL_WANT_READ indicates read() would block.
00219  */
00220 int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len );
00221 
00222 /**
00223  * \brief          Write at most 'len' characters. If no error occurs,
00224  *                 the actual amount read is returned.
00225  *
00226  * \param ctx      Socket
00227  * \param buf      The buffer to read from
00228  * \param len      The length of the buffer
00229  *
00230  * \return         the number of bytes sent,
00231  *                 or a non-zero error code; with a non-blocking socket,
00232  *                 MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block.
00233  */
00234 int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len );
00235 
00236 /**
00237  * \brief          Read at most 'len' characters, blocking for at most
00238  *                 'timeout' seconds. If no error occurs, the actual amount
00239  *                 read is returned.
00240  *
00241  * \param ctx      Socket
00242  * \param buf      The buffer to write to
00243  * \param len      Maximum length of the buffer
00244  * \param timeout  Maximum number of milliseconds to wait for data
00245  *                 0 means no timeout (wait forever)
00246  *
00247  * \return         the number of bytes received,
00248  *                 or a non-zero error code:
00249  *                 MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
00250  *                 MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
00251  *
00252  * \note           This function will block (until data becomes available or
00253  *                 timeout is reached) even if the socket is set to
00254  *                 non-blocking. Handling timeouts with non-blocking reads
00255  *                 requires a different strategy.
00256  */
00257 int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len,
00258                       uint32_t timeout );
00259 
00260 /**
00261  * \brief          Closes down the connection and free associated data
00262  *
00263  * \param ctx      The context to close
00264  */
00265 void mbedtls_net_close( mbedtls_net_context *ctx );
00266 
00267 /**
00268  * \brief          Gracefully shutdown the connection and free associated data
00269  *
00270  * \param ctx      The context to free
00271  */
00272 void mbedtls_net_free( mbedtls_net_context *ctx );
00273 
00274 #ifdef __cplusplus
00275 }
00276 #endif
00277 
00278 #endif /* net_sockets.h */