/** * \file net_sockets.h * * \brief Network sockets abstraction layer to integrate Mbed TLS into a * BSD-style sockets API. * * The network sockets module provides an example integration of the * Mbed TLS library into a BSD sockets implementation. The module is * intended to be an example of how Mbed TLS can be integrated into a * networking stack, as well as to be Mbed TLS's network integration * for its supported platforms. * * The module is intended only to be used with the Mbed TLS library and * is not intended to be used by third party application software * directly. * * The supported platforms are as follows: * * Microsoft Windows and Windows CE * * POSIX/Unix platforms including Linux, OS X * */ /* * Copyright The Mbed TLS Contributors * SPDX-License-Identifier: Apache-2.0 OR GPL-2.0-or-later */ #ifndef MBEDTLS_NET_SOCKETS_H #define MBEDTLS_NET_SOCKETS_H #include "mbedtls/private_access.h" #include "mbedtls/build_info.h" #include "mbedtls/ssl.h" #include #include /** Failed to open a socket. */ #define MBEDTLS_ERR_NET_SOCKET_FAILED -0x0042 /** The connection to the given server / port failed. */ #define MBEDTLS_ERR_NET_CONNECT_FAILED -0x0044 /** Binding of the socket failed. */ #define MBEDTLS_ERR_NET_BIND_FAILED -0x0046 /** Could not listen on the socket. */ #define MBEDTLS_ERR_NET_LISTEN_FAILED -0x0048 /** Could not accept the incoming connection. */ #define MBEDTLS_ERR_NET_ACCEPT_FAILED -0x004A /** Reading information from the socket failed. */ #define MBEDTLS_ERR_NET_RECV_FAILED -0x004C /** Sending information through the socket failed. */ #define MBEDTLS_ERR_NET_SEND_FAILED -0x004E /** Connection was reset by peer. */ #define MBEDTLS_ERR_NET_CONN_RESET -0x0050 /** Failed to get an IP address for the given hostname. */ #define MBEDTLS_ERR_NET_UNKNOWN_HOST -0x0052 /** Buffer is too small to hold the data. */ #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL -0x0043 /** The context is invalid, eg because it was free()ed. */ #define MBEDTLS_ERR_NET_INVALID_CONTEXT -0x0045 /** Polling the net context failed. */ #define MBEDTLS_ERR_NET_POLL_FAILED -0x0047 /** Input invalid. */ #define MBEDTLS_ERR_NET_BAD_INPUT_DATA -0x0049 #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 */ #define MBEDTLS_NET_POLL_READ 1 /**< Used in \c mbedtls_net_poll to check for pending data */ #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */ #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 mbedtls_net_context { /** The underlying file descriptor. * * This field is only guaranteed to be present on POSIX/Unix-like platforms. * On other platforms, it may have a different type, have a different * meaning, or be absent altogether. */ int fd; } 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_UNKNOWN_HOST, * 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 cip_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_SOCKET_FAILED, * MBEDTLS_ERR_NET_BIND_FAILED, * 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 *cip_len); /** * \brief Check and wait for the context to be ready for read/write * * \note The current implementation of this function uses * select() and returns an error if the file descriptor * is \c FD_SETSIZE or greater. * * \param ctx Socket to check * \param rw Bitflag composed of MBEDTLS_NET_POLL_READ and * MBEDTLS_NET_POLL_WRITE specifying the events * to wait for: * - If MBEDTLS_NET_POLL_READ is set, the function * will return as soon as the net context is available * for reading. * - If MBEDTLS_NET_POLL_WRITE is set, the function * will return as soon as the net context is available * for writing. * \param timeout Maximal amount of time to wait before returning, * in milliseconds. If \c timeout is zero, the * function returns immediately. If \c timeout is * -1u, the function blocks potentially indefinitely. * * \return Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE * on success or timeout, or a negative return code otherwise. */ int mbedtls_net_poll(mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout); /** * \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. * * \note The current implementation of this function uses * select() and returns an error if the file descriptor * is \c FD_SETSIZE or greater. * * \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 if successful. * MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out. * MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal. * Another negative error code (MBEDTLS_ERR_NET_xxx) * for other failures. * * \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 Closes down the connection and free associated data * * \param ctx The context to close * * \note This function frees and clears data associated with the * context but does not free the memory pointed to by \p ctx. * This memory is the responsibility of the caller. */ void mbedtls_net_close(mbedtls_net_context *ctx); /** * \brief Gracefully shutdown the connection and free associated data * * \param ctx The context to free * * \note This function frees and clears data associated with the * context but does not free the memory pointed to by \p ctx. * This memory is the responsibility of the caller. */ void mbedtls_net_free(mbedtls_net_context *ctx); #ifdef __cplusplus } #endif #endif /* net_sockets.h */