common/mbedtls/net_sockets.h

   1 /**
   2  * \file net_sockets.h
   3  *
   4  * \brief   Network sockets abstraction layer to integrate Mbed TLS into a
   5  *          BSD-style sockets API.
   6  *
   7  *          The network sockets module provides an example integration of the
   8  *          Mbed TLS library into a BSD sockets implementation. The module is
   9  *          intended to be an example of how Mbed TLS can be integrated into a
  10  *          networking stack, as well as to be Mbed TLS's network integration
  11  *          for its supported platforms.
  12  *
  13  *          The module is intended only to be used with the Mbed TLS library and
  14  *          is not intended to be used by third party application software
  15  *          directly.
  16  *
  17  *          The supported platforms are as follows:
  18  *              * Microsoft Windows and Windows CE
  19  *              * POSIX/Unix platforms including Linux, OS X
  20  *
  21  */
  22 /*
  23  *  Copyright The Mbed TLS Contributors
  24  *  SPDX-License-Identifier: Apache-2.0
  25  *
  26  *  Licensed under the Apache License, Version 2.0 (the "License"); you may
  27  *  not use this file except in compliance with the License.
  28  *  You may obtain a copy of the License at
  29  *
  30  *  http://www.apache.org/licenses/LICENSE-2.0
  31  *
  32  *  Unless required by applicable law or agreed to in writing, software
  33  *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
  34  *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  35  *  See the License for the specific language governing permissions and
  36  *  limitations under the License.
  37  */
  38 #ifndef MBEDTLS_NET_SOCKETS_H
  39 #define MBEDTLS_NET_SOCKETS_H
  40
  41 #if !defined(MBEDTLS_CONFIG_FILE)
  42 #include "mbedtls/config.h"
  43 #else
  44 #include MBEDTLS_CONFIG_FILE
  45 #endif
  46
  47 #include "mbedtls/ssl.h"
  48
  49 #include <stddef.h>
  50 #include <stdint.h>
  51
  52 #define MBEDTLS_ERR_NET_SOCKET_FAILED                     -0x0042  /**< Failed to open a socket. */
  53 #define MBEDTLS_ERR_NET_CONNECT_FAILED                    -0x0044  /**< The connection to the given server / port failed. */
  54 #define MBEDTLS_ERR_NET_BIND_FAILED                       -0x0046  /**< Binding of the socket failed. */
  55 #define MBEDTLS_ERR_NET_LISTEN_FAILED                     -0x0048  /**< Could not listen on the socket. */
  56 #define MBEDTLS_ERR_NET_ACCEPT_FAILED                     -0x004A  /**< Could not accept the incoming connection. */
  57 #define MBEDTLS_ERR_NET_RECV_FAILED                       -0x004C  /**< Reading information from the socket failed. */
  58 #define MBEDTLS_ERR_NET_SEND_FAILED                       -0x004E  /**< Sending information through the socket failed. */
  59 #define MBEDTLS_ERR_NET_CONN_RESET                        -0x0050  /**< Connection was reset by peer. */
  60 #define MBEDTLS_ERR_NET_UNKNOWN_HOST                      -0x0052  /**< Failed to get an IP address for the given hostname. */
  61 #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL                  -0x0043  /**< Buffer is too small to hold the data. */
  62 #define MBEDTLS_ERR_NET_INVALID_CONTEXT                   -0x0045  /**< The context is invalid, eg because it was free()ed. */
  63 #define MBEDTLS_ERR_NET_POLL_FAILED                       -0x0047  /**< Polling the net context failed. */
  64 #define MBEDTLS_ERR_NET_BAD_INPUT_DATA                    -0x0049  /**< Input invalid. */
  65
  66 #define MBEDTLS_NET_LISTEN_BACKLOG         10 /**< The backlog that listen() should use. */
  67
  68 #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */
  69 #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */
  70
  71 #define MBEDTLS_NET_POLL_READ  1 /**< Used in \c mbedtls_net_poll to check for pending data  */
  72 #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */
  73
  74 #ifdef __cplusplus
  75 extern "C" {
  76 #endif
  77
  78 /**
  79  * Wrapper type for sockets.
  80  *
  81  * Currently backed by just a file descriptor, but might be more in the future
  82  * (eg two file descriptors for combined IPv4 + IPv6 support, or additional
  83  * structures for hand-made UDP demultiplexing).
  84  */
  85 typedef struct mbedtls_net_context {
  86     int fd;             /**< The underlying file descriptor                 */
  87 }
  88 mbedtls_net_context;
  89
  90 /**
  91  * \brief          Initialize a context
  92  *                 Just makes the context ready to be used or freed safely.
  93  *
  94  * \param ctx      Context to initialize
  95  */
  96 void mbedtls_net_init(mbedtls_net_context *ctx);
  97
  98 /**
  99  * \brief          Initiate a connection with host:port in the given protocol
 100  *
 101  * \param ctx      Socket to use
 102  * \param host     Host to connect to
 103  * \param port     Port to connect to
 104  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
 105  *
 106  * \return         0 if successful, or one of:
 107  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
 108  *                      MBEDTLS_ERR_NET_UNKNOWN_HOST,
 109  *                      MBEDTLS_ERR_NET_CONNECT_FAILED
 110  *
 111  * \note           Sets the socket in connected mode even with UDP.
 112  */
 113 int mbedtls_net_connect(mbedtls_net_context *ctx, const char *host, const char *port, int proto);
 114
 115 /**
 116  * \brief          Create a receiving socket on bind_ip:port in the chosen
 117  *                 protocol. If bind_ip == NULL, all interfaces are bound.
 118  *
 119  * \param ctx      Socket to use
 120  * \param bind_ip  IP to bind to, can be NULL
 121  * \param port     Port number to use
 122  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
 123  *
 124  * \return         0 if successful, or one of:
 125  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
 126  *                      MBEDTLS_ERR_NET_UNKNOWN_HOST,
 127  *                      MBEDTLS_ERR_NET_BIND_FAILED,
 128  *                      MBEDTLS_ERR_NET_LISTEN_FAILED
 129  *
 130  * \note           Regardless of the protocol, opens the sockets and binds it.
 131  *                 In addition, make the socket listening if protocol is TCP.
 132  */
 133 int mbedtls_net_bind(mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto);
 134
 135 /**
 136  * \brief           Accept a connection from a remote client
 137  *
 138  * \param bind_ctx  Relevant socket
 139  * \param client_ctx Will contain the connected client socket
 140  * \param client_ip Will contain the client IP address, can be NULL
 141  * \param buf_size  Size of the client_ip buffer
 142  * \param ip_len    Will receive the size of the client IP written,
 143  *                  can be NULL if client_ip is null
 144  *
 145  * \return          0 if successful, or
 146  *                  MBEDTLS_ERR_NET_SOCKET_FAILED,
 147  *                  MBEDTLS_ERR_NET_BIND_FAILED,
 148  *                  MBEDTLS_ERR_NET_ACCEPT_FAILED, or
 149  *                  MBEDTLS_ERR_NET_BUFFER_TOO_SMALL if buf_size is too small,
 150  *                  MBEDTLS_ERR_SSL_WANT_READ if bind_fd was set to
 151  *                  non-blocking and accept() would block.
 152  */
 153 int mbedtls_net_accept(mbedtls_net_context *bind_ctx,
 154                        mbedtls_net_context *client_ctx,
 155                        void *client_ip, size_t buf_size, size_t *ip_len);
 156
 157 /**
 158  * \brief          Check and wait for the context to be ready for read/write
 159  *
 160  * \note           The current implementation of this function uses
 161  *                 select() and returns an error if the file descriptor
 162  *                 is \c FD_SETSIZE or greater.
 163  *
 164  * \param ctx      Socket to check
 165  * \param rw       Bitflag composed of MBEDTLS_NET_POLL_READ and
 166  *                 MBEDTLS_NET_POLL_WRITE specifying the events
 167  *                 to wait for:
 168  *                 - If MBEDTLS_NET_POLL_READ is set, the function
 169  *                   will return as soon as the net context is available
 170  *                   for reading.
 171  *                 - If MBEDTLS_NET_POLL_WRITE is set, the function
 172  *                   will return as soon as the net context is available
 173  *                   for writing.
 174  * \param timeout  Maximal amount of time to wait before returning,
 175  *                 in milliseconds. If \c timeout is zero, the
 176  *                 function returns immediately. If \c timeout is
 177  *                 -1u, the function blocks potentially indefinitely.
 178  *
 179  * \return         Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE
 180  *                 on success or timeout, or a negative return code otherwise.
 181  */
 182 int mbedtls_net_poll(mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout);
 183
 184 /**
 185  * \brief          Set the socket blocking
 186  *
 187  * \param ctx      Socket to set
 188  *
 189  * \return         0 if successful, or a non-zero error code
 190  */
 191 int mbedtls_net_set_block(mbedtls_net_context *ctx);
 192
 193 /**
 194  * \brief          Set the socket non-blocking
 195  *
 196  * \param ctx      Socket to set
 197  *
 198  * \return         0 if successful, or a non-zero error code
 199  */
 200 int mbedtls_net_set_nonblock(mbedtls_net_context *ctx);
 201
 202 /**
 203  * \brief          Portable usleep helper
 204  *
 205  * \param usec     Amount of microseconds to sleep
 206  *
 207  * \note           Real amount of time slept will not be less than
 208  *                 select()'s timeout granularity (typically, 10ms).
 209  */
 210 void mbedtls_net_usleep(unsigned long usec);
 211
 212 /**
 213  * \brief          Read at most 'len' characters. If no error occurs,
 214  *                 the actual amount read is returned.
 215  *
 216  * \param ctx      Socket
 217  * \param buf      The buffer to write to
 218  * \param len      Maximum length of the buffer
 219  *
 220  * \return         the number of bytes received,
 221  *                 or a non-zero error code; with a non-blocking socket,
 222  *                 MBEDTLS_ERR_SSL_WANT_READ indicates read() would block.
 223  */
 224 int mbedtls_net_recv(void *ctx, unsigned char *buf, size_t len);
 225
 226 /**
 227  * \brief          Write at most 'len' characters. If no error occurs,
 228  *                 the actual amount read is returned.
 229  *
 230  * \param ctx      Socket
 231  * \param buf      The buffer to read from
 232  * \param len      The length of the buffer
 233  *
 234  * \return         the number of bytes sent,
 235  *                 or a non-zero error code; with a non-blocking socket,
 236  *                 MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block.
 237  */
 238 int mbedtls_net_send(void *ctx, const unsigned char *buf, size_t len);
 239
 240 /**
 241  * \brief          Read at most 'len' characters, blocking for at most
 242  *                 'timeout' seconds. If no error occurs, the actual amount
 243  *                 read is returned.
 244  *
 245  * \note           The current implementation of this function uses
 246  *                 select() and returns an error if the file descriptor
 247  *                 is \c FD_SETSIZE or greater.
 248  *
 249  * \param ctx      Socket
 250  * \param buf      The buffer to write to
 251  * \param len      Maximum length of the buffer
 252  * \param timeout  Maximum number of milliseconds to wait for data
 253  *                 0 means no timeout (wait forever)
 254  *
 255  * \return         The number of bytes received if successful.
 256  *                 MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out.
 257  *                 MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
 258  *                 Another negative error code (MBEDTLS_ERR_NET_xxx)
 259  *                 for other failures.
 260  *
 261  * \note           This function will block (until data becomes available or
 262  *                 timeout is reached) even if the socket is set to
 263  *                 non-blocking. Handling timeouts with non-blocking reads
 264  *                 requires a different strategy.
 265  */
 266 int mbedtls_net_recv_timeout(void *ctx, unsigned char *buf, size_t len,
 267                              uint32_t timeout);
 268
 269 /**
 270  * \brief          Closes down the connection and free associated data
 271  *
 272  * \param ctx      The context to close
 273  */
 274 void mbedtls_net_close(mbedtls_net_context *ctx);
 275
 276 /**
 277  * \brief          Gracefully shutdown the connection and free associated data
 278  *
 279  * \param ctx      The context to free
 280  */
 281 void mbedtls_net_free(mbedtls_net_context *ctx);
 282
 283 #ifdef __cplusplus
 284 }
 285 #endif
 286
 287 #endif /* net_sockets.h */