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 OR GPL-2.0-or-later 25 */ 26 #ifndef MBEDTLS_NET_SOCKETS_H 27 #define MBEDTLS_NET_SOCKETS_H 28 #include "mbedtls/private_access.h" 29 30 #include "mbedtls/build_info.h" 31 32 #include "mbedtls/ssl.h" 33 34 #include <stddef.h> 35 #include <stdint.h> 36 37 /** Failed to open a socket. */ 38 #define MBEDTLS_ERR_NET_SOCKET_FAILED -0x0042 39 /** The connection to the given server / port failed. */ 40 #define MBEDTLS_ERR_NET_CONNECT_FAILED -0x0044 41 /** Binding of the socket failed. */ 42 #define MBEDTLS_ERR_NET_BIND_FAILED -0x0046 43 /** Could not listen on the socket. */ 44 #define MBEDTLS_ERR_NET_LISTEN_FAILED -0x0048 45 /** Could not accept the incoming connection. */ 46 #define MBEDTLS_ERR_NET_ACCEPT_FAILED -0x004A 47 /** Reading information from the socket failed. */ 48 #define MBEDTLS_ERR_NET_RECV_FAILED -0x004C 49 /** Sending information through the socket failed. */ 50 #define MBEDTLS_ERR_NET_SEND_FAILED -0x004E 51 /** Connection was reset by peer. */ 52 #define MBEDTLS_ERR_NET_CONN_RESET -0x0050 53 /** Failed to get an IP address for the given hostname. */ 54 #define MBEDTLS_ERR_NET_UNKNOWN_HOST -0x0052 55 /** Buffer is too small to hold the data. */ 56 #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL -0x0043 57 /** The context is invalid, eg because it was free()ed. */ 58 #define MBEDTLS_ERR_NET_INVALID_CONTEXT -0x0045 59 /** Polling the net context failed. */ 60 #define MBEDTLS_ERR_NET_POLL_FAILED -0x0047 61 /** Input invalid. */ 62 #define MBEDTLS_ERR_NET_BAD_INPUT_DATA -0x0049 63 64 #define MBEDTLS_NET_LISTEN_BACKLOG 10 /**< The backlog that listen() should use. */ 65 66 #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */ 67 #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */ 68 69 #define MBEDTLS_NET_POLL_READ 1 /**< Used in \c mbedtls_net_poll to check for pending data */ 70 #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */ 71 72 #ifdef __cplusplus 73 extern "C" { 74 #endif 75 76 /** 77 * Wrapper type for sockets. 78 * 79 * Currently backed by just a file descriptor, but might be more in the future 80 * (eg two file descriptors for combined IPv4 + IPv6 support, or additional 81 * structures for hand-made UDP demultiplexing). 82 */ 83 typedef struct mbedtls_net_context { 84 /** The underlying file descriptor. 85 * 86 * This field is only guaranteed to be present on POSIX/Unix-like platforms. 87 * On other platforms, it may have a different type, have a different 88 * meaning, or be absent altogether. 89 */ 90 int fd; 91 } 92 mbedtls_net_context; 93 94 /** 95 * \brief Initialize a context 96 * Just makes the context ready to be used or freed safely. 97 * 98 * \param ctx Context to initialize 99 */ 100 void mbedtls_net_init(mbedtls_net_context *ctx); 101 102 /** 103 * \brief Initiate a connection with host:port in the given protocol 104 * 105 * \param ctx Socket to use 106 * \param host Host to connect to 107 * \param port Port to connect to 108 * \param proto Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP 109 * 110 * \return 0 if successful, or one of: 111 * MBEDTLS_ERR_NET_SOCKET_FAILED, 112 * MBEDTLS_ERR_NET_UNKNOWN_HOST, 113 * MBEDTLS_ERR_NET_CONNECT_FAILED 114 * 115 * \note Sets the socket in connected mode even with UDP. 116 */ 117 int mbedtls_net_connect(mbedtls_net_context *ctx, const char *host, const char *port, int proto); 118 119 /** 120 * \brief Create a receiving socket on bind_ip:port in the chosen 121 * protocol. If bind_ip == NULL, all interfaces are bound. 122 * 123 * \param ctx Socket to use 124 * \param bind_ip IP to bind to, can be NULL 125 * \param port Port number to use 126 * \param proto Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP 127 * 128 * \return 0 if successful, or one of: 129 * MBEDTLS_ERR_NET_SOCKET_FAILED, 130 * MBEDTLS_ERR_NET_UNKNOWN_HOST, 131 * MBEDTLS_ERR_NET_BIND_FAILED, 132 * MBEDTLS_ERR_NET_LISTEN_FAILED 133 * 134 * \note Regardless of the protocol, opens the sockets and binds it. 135 * In addition, make the socket listening if protocol is TCP. 136 */ 137 int mbedtls_net_bind(mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto); 138 139 /** 140 * \brief Accept a connection from a remote client 141 * 142 * \param bind_ctx Relevant socket 143 * \param client_ctx Will contain the connected client socket 144 * \param client_ip Will contain the client IP address, can be NULL 145 * \param buf_size Size of the client_ip buffer 146 * \param cip_len Will receive the size of the client IP written, 147 * can be NULL if client_ip is null 148 * 149 * \return 0 if successful, or 150 * MBEDTLS_ERR_NET_SOCKET_FAILED, 151 * MBEDTLS_ERR_NET_BIND_FAILED, 152 * MBEDTLS_ERR_NET_ACCEPT_FAILED, or 153 * MBEDTLS_ERR_NET_BUFFER_TOO_SMALL if buf_size is too small, 154 * MBEDTLS_ERR_SSL_WANT_READ if bind_fd was set to 155 * non-blocking and accept() would block. 156 */ 157 int mbedtls_net_accept(mbedtls_net_context *bind_ctx, 158 mbedtls_net_context *client_ctx, 159 void *client_ip, size_t buf_size, size_t *cip_len); 160 161 /** 162 * \brief Check and wait for the context to be ready for read/write 163 * 164 * \note The current implementation of this function uses 165 * select() and returns an error if the file descriptor 166 * is \c FD_SETSIZE or greater. 167 * 168 * \param ctx Socket to check 169 * \param rw Bitflag composed of MBEDTLS_NET_POLL_READ and 170 * MBEDTLS_NET_POLL_WRITE specifying the events 171 * to wait for: 172 * - If MBEDTLS_NET_POLL_READ is set, the function 173 * will return as soon as the net context is available 174 * for reading. 175 * - If MBEDTLS_NET_POLL_WRITE is set, the function 176 * will return as soon as the net context is available 177 * for writing. 178 * \param timeout Maximal amount of time to wait before returning, 179 * in milliseconds. If \c timeout is zero, the 180 * function returns immediately. If \c timeout is 181 * -1u, the function blocks potentially indefinitely. 182 * 183 * \return Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE 184 * on success or timeout, or a negative return code otherwise. 185 */ 186 int mbedtls_net_poll(mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout); 187 188 /** 189 * \brief Set the socket blocking 190 * 191 * \param ctx Socket to set 192 * 193 * \return 0 if successful, or a non-zero error code 194 */ 195 int mbedtls_net_set_block(mbedtls_net_context *ctx); 196 197 /** 198 * \brief Set the socket non-blocking 199 * 200 * \param ctx Socket to set 201 * 202 * \return 0 if successful, or a non-zero error code 203 */ 204 int mbedtls_net_set_nonblock(mbedtls_net_context *ctx); 205 206 /** 207 * \brief Portable usleep helper 208 * 209 * \param usec Amount of microseconds to sleep 210 * 211 * \note Real amount of time slept will not be less than 212 * select()'s timeout granularity (typically, 10ms). 213 */ 214 void mbedtls_net_usleep(unsigned long usec); 215 216 /** 217 * \brief Read at most 'len' characters. If no error occurs, 218 * the actual amount read is returned. 219 * 220 * \param ctx Socket 221 * \param buf The buffer to write to 222 * \param len Maximum length of the buffer 223 * 224 * \return the number of bytes received, 225 * or a non-zero error code; with a non-blocking socket, 226 * MBEDTLS_ERR_SSL_WANT_READ indicates read() would block. 227 */ 228 int mbedtls_net_recv(void *ctx, unsigned char *buf, size_t len); 229 230 /** 231 * \brief Write at most 'len' characters. If no error occurs, 232 * the actual amount read is returned. 233 * 234 * \param ctx Socket 235 * \param buf The buffer to read from 236 * \param len The length of the buffer 237 * 238 * \return the number of bytes sent, 239 * or a non-zero error code; with a non-blocking socket, 240 * MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block. 241 */ 242 int mbedtls_net_send(void *ctx, const unsigned char *buf, size_t len); 243 244 /** 245 * \brief Read at most 'len' characters, blocking for at most 246 * 'timeout' seconds. If no error occurs, the actual amount 247 * read is returned. 248 * 249 * \note The current implementation of this function uses 250 * select() and returns an error if the file descriptor 251 * is \c FD_SETSIZE or greater. 252 * 253 * \param ctx Socket 254 * \param buf The buffer to write to 255 * \param len Maximum length of the buffer 256 * \param timeout Maximum number of milliseconds to wait for data 257 * 0 means no timeout (wait forever) 258 * 259 * \return The number of bytes received if successful. 260 * MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out. 261 * MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal. 262 * Another negative error code (MBEDTLS_ERR_NET_xxx) 263 * for other failures. 264 * 265 * \note This function will block (until data becomes available or 266 * timeout is reached) even if the socket is set to 267 * non-blocking. Handling timeouts with non-blocking reads 268 * requires a different strategy. 269 */ 270 int mbedtls_net_recv_timeout(void *ctx, unsigned char *buf, size_t len, 271 uint32_t timeout); 272 273 /** 274 * \brief Closes down the connection and free associated data 275 * 276 * \param ctx The context to close 277 * 278 * \note This function frees and clears data associated with the 279 * context but does not free the memory pointed to by \p ctx. 280 * This memory is the responsibility of the caller. 281 */ 282 void mbedtls_net_close(mbedtls_net_context *ctx); 283 284 /** 285 * \brief Gracefully shutdown the connection and free associated data 286 * 287 * \param ctx The context to free 288 * 289 * \note This function frees and clears data associated with the 290 * context but does not free the memory pointed to by \p ctx. 291 * This memory is the responsibility of the caller. 292 */ 293 void mbedtls_net_free(mbedtls_net_context *ctx); 294 295 #ifdef __cplusplus 296 } 297 #endif 298 299 #endif /* net_sockets.h */ 300
