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 #include "mbedtls/private_access.h" 41 42 #include "mbedtls/build_info.h" 43 44 #include "mbedtls/ssl.h" 45 46 #include <stddef.h> 47 #include <stdint.h> 48 49 /** Failed to open a socket. */ 50 #define MBEDTLS_ERR_NET_SOCKET_FAILED -0x0042 51 /** The connection to the given server / port failed. */ 52 #define MBEDTLS_ERR_NET_CONNECT_FAILED -0x0044 53 /** Binding of the socket failed. */ 54 #define MBEDTLS_ERR_NET_BIND_FAILED -0x0046 55 /** Could not listen on the socket. */ 56 #define MBEDTLS_ERR_NET_LISTEN_FAILED -0x0048 57 /** Could not accept the incoming connection. */ 58 #define MBEDTLS_ERR_NET_ACCEPT_FAILED -0x004A 59 /** Reading information from the socket failed. */ 60 #define MBEDTLS_ERR_NET_RECV_FAILED -0x004C 61 /** Sending information through the socket failed. */ 62 #define MBEDTLS_ERR_NET_SEND_FAILED -0x004E 63 /** Connection was reset by peer. */ 64 #define MBEDTLS_ERR_NET_CONN_RESET -0x0050 65 /** Failed to get an IP address for the given hostname. */ 66 #define MBEDTLS_ERR_NET_UNKNOWN_HOST -0x0052 67 /** Buffer is too small to hold the data. */ 68 #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL -0x0043 69 /** The context is invalid, eg because it was free()ed. */ 70 #define MBEDTLS_ERR_NET_INVALID_CONTEXT -0x0045 71 /** Polling the net context failed. */ 72 #define MBEDTLS_ERR_NET_POLL_FAILED -0x0047 73 /** Input invalid. */ 74 #define MBEDTLS_ERR_NET_BAD_INPUT_DATA -0x0049 75 76 #define MBEDTLS_NET_LISTEN_BACKLOG 10 /**< The backlog that listen() should use. */ 77 78 #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */ 79 #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */ 80 81 #define MBEDTLS_NET_POLL_READ 1 /**< Used in \c mbedtls_net_poll to check for pending data */ 82 #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */ 83 84 #ifdef __cplusplus 85 extern "C" { 86 #endif 87 88 /** 89 * Wrapper type for sockets. 90 * 91 * Currently backed by just a file descriptor, but might be more in the future 92 * (eg two file descriptors for combined IPv4 + IPv6 support, or additional 93 * structures for hand-made UDP demultiplexing). 94 */ 95 typedef struct mbedtls_net_context 96 { 97 /** The underlying file descriptor. 98 * 99 * This field is only guaranteed to be present on POSIX/Unix-like platforms. 100 * On other platforms, it may have a different type, have a different 101 * meaning, or be absent altogether. 102 */ 103 int fd; 104 } 105 mbedtls_net_context; 106 107 /** 108 * \brief Initialize a context 109 * Just makes the context ready to be used or freed safely. 110 * 111 * \param ctx Context to initialize 112 */ 113 void mbedtls_net_init( mbedtls_net_context *ctx ); 114 115 /** 116 * \brief Initiate a connection with host:port in the given protocol 117 * 118 * \param ctx Socket to use 119 * \param host Host to connect to 120 * \param port Port to connect to 121 * \param proto Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP 122 * 123 * \return 0 if successful, or one of: 124 * MBEDTLS_ERR_NET_SOCKET_FAILED, 125 * MBEDTLS_ERR_NET_UNKNOWN_HOST, 126 * MBEDTLS_ERR_NET_CONNECT_FAILED 127 * 128 * \note Sets the socket in connected mode even with UDP. 129 */ 130 int mbedtls_net_connect( mbedtls_net_context *ctx, const char *host, const char *port, int proto ); 131 132 /** 133 * \brief Create a receiving socket on bind_ip:port in the chosen 134 * protocol. If bind_ip == NULL, all interfaces are bound. 135 * 136 * \param ctx Socket to use 137 * \param bind_ip IP to bind to, can be NULL 138 * \param port Port number to use 139 * \param proto Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP 140 * 141 * \return 0 if successful, or one of: 142 * MBEDTLS_ERR_NET_SOCKET_FAILED, 143 * MBEDTLS_ERR_NET_UNKNOWN_HOST, 144 * MBEDTLS_ERR_NET_BIND_FAILED, 145 * MBEDTLS_ERR_NET_LISTEN_FAILED 146 * 147 * \note Regardless of the protocol, opens the sockets and binds it. 148 * In addition, make the socket listening if protocol is TCP. 149 */ 150 int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto ); 151 152 /** 153 * \brief Accept a connection from a remote client 154 * 155 * \param bind_ctx Relevant socket 156 * \param client_ctx Will contain the connected client socket 157 * \param client_ip Will contain the client IP address, can be NULL 158 * \param buf_size Size of the client_ip buffer 159 * \param ip_len Will receive the size of the client IP written, 160 * can be NULL if client_ip is null 161 * 162 * \return 0 if successful, or 163 * MBEDTLS_ERR_NET_SOCKET_FAILED, 164 * MBEDTLS_ERR_NET_BIND_FAILED, 165 * MBEDTLS_ERR_NET_ACCEPT_FAILED, or 166 * MBEDTLS_ERR_NET_BUFFER_TOO_SMALL if buf_size is too small, 167 * MBEDTLS_ERR_SSL_WANT_READ if bind_fd was set to 168 * non-blocking and accept() would block. 169 */ 170 int mbedtls_net_accept( mbedtls_net_context *bind_ctx, 171 mbedtls_net_context *client_ctx, 172 void *client_ip, size_t buf_size, size_t *ip_len ); 173 174 /** 175 * \brief Check and wait for the context to be ready for read/write 176 * 177 * \note The current implementation of this function uses 178 * select() and returns an error if the file descriptor 179 * is \c FD_SETSIZE or greater. 180 * 181 * \param ctx Socket to check 182 * \param rw Bitflag composed of MBEDTLS_NET_POLL_READ and 183 * MBEDTLS_NET_POLL_WRITE specifying the events 184 * to wait for: 185 * - If MBEDTLS_NET_POLL_READ is set, the function 186 * will return as soon as the net context is available 187 * for reading. 188 * - If MBEDTLS_NET_POLL_WRITE is set, the function 189 * will return as soon as the net context is available 190 * for writing. 191 * \param timeout Maximal amount of time to wait before returning, 192 * in milliseconds. If \c timeout is zero, the 193 * function returns immediately. If \c timeout is 194 * -1u, the function blocks potentially indefinitely. 195 * 196 * \return Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE 197 * on success or timeout, or a negative return code otherwise. 198 */ 199 int mbedtls_net_poll( mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout ); 200 201 /** 202 * \brief Set the socket blocking 203 * 204 * \param ctx Socket to set 205 * 206 * \return 0 if successful, or a non-zero error code 207 */ 208 int mbedtls_net_set_block( mbedtls_net_context *ctx ); 209 210 /** 211 * \brief Set the socket non-blocking 212 * 213 * \param ctx Socket to set 214 * 215 * \return 0 if successful, or a non-zero error code 216 */ 217 int mbedtls_net_set_nonblock( mbedtls_net_context *ctx ); 218 219 /** 220 * \brief Portable usleep helper 221 * 222 * \param usec Amount of microseconds to sleep 223 * 224 * \note Real amount of time slept will not be less than 225 * select()'s timeout granularity (typically, 10ms). 226 */ 227 void mbedtls_net_usleep( unsigned long usec ); 228 229 /** 230 * \brief Read at most 'len' characters. If no error occurs, 231 * the actual amount read is returned. 232 * 233 * \param ctx Socket 234 * \param buf The buffer to write to 235 * \param len Maximum length of the buffer 236 * 237 * \return the number of bytes received, 238 * or a non-zero error code; with a non-blocking socket, 239 * MBEDTLS_ERR_SSL_WANT_READ indicates read() would block. 240 */ 241 int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len ); 242 243 /** 244 * \brief Write at most 'len' characters. If no error occurs, 245 * the actual amount read is returned. 246 * 247 * \param ctx Socket 248 * \param buf The buffer to read from 249 * \param len The length of the buffer 250 * 251 * \return the number of bytes sent, 252 * or a non-zero error code; with a non-blocking socket, 253 * MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block. 254 */ 255 int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len ); 256 257 /** 258 * \brief Read at most 'len' characters, blocking for at most 259 * 'timeout' seconds. If no error occurs, the actual amount 260 * read is returned. 261 * 262 * \note The current implementation of this function uses 263 * select() and returns an error if the file descriptor 264 * is \c FD_SETSIZE or greater. 265 * 266 * \param ctx Socket 267 * \param buf The buffer to write to 268 * \param len Maximum length of the buffer 269 * \param timeout Maximum number of milliseconds to wait for data 270 * 0 means no timeout (wait forever) 271 * 272 * \return The number of bytes received if successful. 273 * MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out. 274 * MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal. 275 * Another negative error code (MBEDTLS_ERR_NET_xxx) 276 * for other failures. 277 * 278 * \note This function will block (until data becomes available or 279 * timeout is reached) even if the socket is set to 280 * non-blocking. Handling timeouts with non-blocking reads 281 * requires a different strategy. 282 */ 283 int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len, 284 uint32_t timeout ); 285 286 /** 287 * \brief Closes down the connection and free associated data 288 * 289 * \param ctx The context to close 290 */ 291 void mbedtls_net_close( mbedtls_net_context *ctx ); 292 293 /** 294 * \brief Gracefully shutdown the connection and free associated data 295 * 296 * \param ctx The context to free 297 */ 298 void mbedtls_net_free( mbedtls_net_context *ctx ); 299 300 #ifdef __cplusplus 301 } 302 #endif 303 304 #endif /* net_sockets.h */ 305