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 (C) 2006-2015, ARM Limited, All Rights Reserved
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  *  This file is part of mbed TLS (https://tls.mbed.org)
39  */
40 #ifndef MBEDTLS_NET_SOCKETS_H
41 #define MBEDTLS_NET_SOCKETS_H
42 
43 #if !defined(MBEDTLS_CONFIG_FILE)
44 #include "config.h"
45 #else
46 #include MBEDTLS_CONFIG_FILE
47 #endif
48 
49 #include "ssl.h"
50 
51 #include <stddef.h>
52 #include <stdint.h>
53 
54 #define MBEDTLS_ERR_NET_SOCKET_FAILED                     -0x0042  /**< Failed to open a socket. */
55 #define MBEDTLS_ERR_NET_CONNECT_FAILED                    -0x0044  /**< The connection to the given server / port failed. */
56 #define MBEDTLS_ERR_NET_BIND_FAILED                       -0x0046  /**< Binding of the socket failed. */
57 #define MBEDTLS_ERR_NET_LISTEN_FAILED                     -0x0048  /**< Could not listen on the socket. */
58 #define MBEDTLS_ERR_NET_ACCEPT_FAILED                     -0x004A  /**< Could not accept the incoming connection. */
59 #define MBEDTLS_ERR_NET_RECV_FAILED                       -0x004C  /**< Reading information from the socket failed. */
60 #define MBEDTLS_ERR_NET_SEND_FAILED                       -0x004E  /**< Sending information through the socket failed. */
61 #define MBEDTLS_ERR_NET_CONN_RESET                        -0x0050  /**< Connection was reset by peer. */
62 #define MBEDTLS_ERR_NET_UNKNOWN_HOST                      -0x0052  /**< Failed to get an IP address for the given hostname. */
63 #define MBEDTLS_ERR_NET_BUFFER_TOO_SMALL                  -0x0043  /**< Buffer is too small to hold the data. */
64 #define MBEDTLS_ERR_NET_INVALID_CONTEXT                   -0x0045  /**< The context is invalid, eg because it was free()ed. */
65 #define MBEDTLS_ERR_NET_POLL_FAILED                       -0x0047  /**< Polling the net context failed. */
66 #define MBEDTLS_ERR_NET_BAD_INPUT_DATA                    -0x0049  /**< Input invalid. */
67 
68 #define MBEDTLS_NET_LISTEN_BACKLOG         10 /**< The backlog that listen() should use. */
69 
70 #define MBEDTLS_NET_PROTO_TCP 0 /**< The TCP transport protocol */
71 #define MBEDTLS_NET_PROTO_UDP 1 /**< The UDP transport protocol */
72 
73 #define MBEDTLS_NET_POLL_READ  1 /**< Used in \c mbedtls_net_poll to check for pending data  */
74 #define MBEDTLS_NET_POLL_WRITE 2 /**< Used in \c mbedtls_net_poll to check if write possible */
75 
76 #ifdef __cplusplus
77 extern "C" {
78 #endif
79 
80 /**
81  * Wrapper type for sockets.
82  *
83  * Currently backed by just a file descriptor, but might be more in the future
84  * (eg two file descriptors for combined IPv4 + IPv6 support, or additional
85  * structures for hand-made UDP demultiplexing).
86  */
87 typedef struct mbedtls_net_context
88 {
89     int fd;             /**< The underlying file descriptor                 */
90 }
91 mbedtls_net_context;
92 
93 /**
94  * \brief          Initialize a context
95  *                 Just makes the context ready to be used or freed safely.
96  *
97  * \param ctx      Context to initialize
98  */
99 void mbedtls_net_init( mbedtls_net_context *ctx );
100 
101 /**
102  * \brief          Initiate a connection with host:port in the given protocol
103  *
104  * \param ctx      Socket to use
105  * \param host     Host to connect to
106  * \param port     Port to connect to
107  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
108  *
109  * \return         0 if successful, or one of:
110  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
111  *                      MBEDTLS_ERR_NET_UNKNOWN_HOST,
112  *                      MBEDTLS_ERR_NET_CONNECT_FAILED
113  *
114  * \note           Sets the socket in connected mode even with UDP.
115  */
116 int mbedtls_net_connect( mbedtls_net_context *ctx, const char *host, const char *port, int proto );
117 
118 /**
119  * \brief          Create a receiving socket on bind_ip:port in the chosen
120  *                 protocol. If bind_ip == NULL, all interfaces are bound.
121  *
122  * \param ctx      Socket to use
123  * \param bind_ip  IP to bind to, can be NULL
124  * \param port     Port number to use
125  * \param proto    Protocol: MBEDTLS_NET_PROTO_TCP or MBEDTLS_NET_PROTO_UDP
126  *
127  * \return         0 if successful, or one of:
128  *                      MBEDTLS_ERR_NET_SOCKET_FAILED,
129  *                      MBEDTLS_ERR_NET_BIND_FAILED,
130  *                      MBEDTLS_ERR_NET_LISTEN_FAILED
131  *
132  * \note           Regardless of the protocol, opens the sockets and binds it.
133  *                 In addition, make the socket listening if protocol is TCP.
134  */
135 int mbedtls_net_bind( mbedtls_net_context *ctx, const char *bind_ip, const char *port, int proto );
136 
137 /**
138  * \brief           Accept a connection from a remote client
139  *
140  * \param bind_ctx  Relevant socket
141  * \param client_ctx Will contain the connected client socket
142  * \param client_ip Will contain the client IP address, can be NULL
143  * \param buf_size  Size of the client_ip buffer
144  * \param ip_len    Will receive the size of the client IP written,
145  *                  can be NULL if client_ip is null
146  *
147  * \return          0 if successful, or
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  * \param ctx      Socket to check
161  * \param rw       Bitflag composed of MBEDTLS_NET_POLL_READ and
162  *                 MBEDTLS_NET_POLL_WRITE specifying the events
163  *                 to wait for:
164  *                 - If MBEDTLS_NET_POLL_READ is set, the function
165  *                   will return as soon as the net context is available
166  *                   for reading.
167  *                 - If MBEDTLS_NET_POLL_WRITE is set, the function
168  *                   will return as soon as the net context is available
169  *                   for writing.
170  * \param timeout  Maximal amount of time to wait before returning,
171  *                 in milliseconds. If \c timeout is zero, the
172  *                 function returns immediately. If \c timeout is
173  *                 -1u, the function blocks potentially indefinitely.
174  *
175  * \return         Bitmask composed of MBEDTLS_NET_POLL_READ/WRITE
176  *                 on success or timeout, or a negative return code otherwise.
177  */
178 int mbedtls_net_poll( mbedtls_net_context *ctx, uint32_t rw, uint32_t timeout );
179 
180 /**
181  * \brief          Set the socket blocking
182  *
183  * \param ctx      Socket to set
184  *
185  * \return         0 if successful, or a non-zero error code
186  */
187 int mbedtls_net_set_block( mbedtls_net_context *ctx );
188 
189 /**
190  * \brief          Set the socket non-blocking
191  *
192  * \param ctx      Socket to set
193  *
194  * \return         0 if successful, or a non-zero error code
195  */
196 int mbedtls_net_set_nonblock( mbedtls_net_context *ctx );
197 
198 /**
199  * \brief          Portable usleep helper
200  *
201  * \param usec     Amount of microseconds to sleep
202  *
203  * \note           Real amount of time slept will not be less than
204  *                 select()'s timeout granularity (typically, 10ms).
205  */
206 void mbedtls_net_usleep( unsigned long usec );
207 
208 /**
209  * \brief          Read at most 'len' characters. If no error occurs,
210  *                 the actual amount read is returned.
211  *
212  * \param ctx      Socket
213  * \param buf      The buffer to write to
214  * \param len      Maximum length of the buffer
215  *
216  * \return         the number of bytes received,
217  *                 or a non-zero error code; with a non-blocking socket,
218  *                 MBEDTLS_ERR_SSL_WANT_READ indicates read() would block.
219  */
220 int mbedtls_net_recv( void *ctx, unsigned char *buf, size_t len );
221 
222 /**
223  * \brief          Write at most 'len' characters. If no error occurs,
224  *                 the actual amount read is returned.
225  *
226  * \param ctx      Socket
227  * \param buf      The buffer to read from
228  * \param len      The length of the buffer
229  *
230  * \return         the number of bytes sent,
231  *                 or a non-zero error code; with a non-blocking socket,
232  *                 MBEDTLS_ERR_SSL_WANT_WRITE indicates write() would block.
233  */
234 int mbedtls_net_send( void *ctx, const unsigned char *buf, size_t len );
235 
236 /**
237  * \brief          Read at most 'len' characters, blocking for at most
238  *                 'timeout' seconds. If no error occurs, the actual amount
239  *                 read is returned.
240  *
241  * \param ctx      Socket
242  * \param buf      The buffer to write to
243  * \param len      Maximum length of the buffer
244  * \param timeout  Maximum number of milliseconds to wait for data
245  *                 0 means no timeout (wait forever)
246  *
247  * \return         the number of bytes received,
248  *                 or a non-zero error code:
249  *                 MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
250  *                 MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
251  *
252  * \note           This function will block (until data becomes available or
253  *                 timeout is reached) even if the socket is set to
254  *                 non-blocking. Handling timeouts with non-blocking reads
255  *                 requires a different strategy.
256  */
257 int mbedtls_net_recv_timeout( void *ctx, unsigned char *buf, size_t len,
258                       uint32_t timeout );
259 
260 /**
261  * \brief          Gracefully shutdown the connection and free associated data
262  *
263  * \param ctx      The context to free
264  */
265 void mbedtls_net_free( mbedtls_net_context *ctx );
266 
267 #ifdef __cplusplus
268 }
269 #endif
270 
271 #endif /* net_sockets.h */
272