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/**
* \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 <stddef.h>
#include <stdint.h>
/** 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 */