xref: /reactos/sdk/include/reactos/libs/mbedtls/ssl.h (revision c2c66aff)
1 /**
2  * \file ssl.h
3  *
4  * \brief SSL/TLS functions.
5  *
6  *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
7  *  SPDX-License-Identifier: GPL-2.0
8  *
9  *  This program is free software; you can redistribute it and/or modify
10  *  it under the terms of the GNU General Public License as published by
11  *  the Free Software Foundation; either version 2 of the License, or
12  *  (at your option) any later version.
13  *
14  *  This program is distributed in the hope that it will be useful,
15  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
16  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
17  *  GNU General Public License for more details.
18  *
19  *  You should have received a copy of the GNU General Public License along
20  *  with this program; if not, write to the Free Software Foundation, Inc.,
21  *  51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22  *
23  *  This file is part of mbed TLS (https://tls.mbed.org)
24  */
25 #ifndef MBEDTLS_SSL_H
26 #define MBEDTLS_SSL_H
27 
28 #if !defined(MBEDTLS_CONFIG_FILE)
29 #include "config.h"
30 #else
31 #include MBEDTLS_CONFIG_FILE
32 #endif
33 
34 #include "bignum.h"
35 #include "ecp.h"
36 
37 #include "ssl_ciphersuites.h"
38 
39 #if defined(MBEDTLS_X509_CRT_PARSE_C)
40 #include "x509_crt.h"
41 #include "x509_crl.h"
42 #endif
43 
44 #if defined(MBEDTLS_DHM_C)
45 #include "dhm.h"
46 #endif
47 
48 #if defined(MBEDTLS_ECDH_C)
49 #include "ecdh.h"
50 #endif
51 
52 #if defined(MBEDTLS_ZLIB_SUPPORT)
53 #include "zlib.h"
54 #endif
55 
56 #if defined(MBEDTLS_HAVE_TIME)
57 #include "mbedtls/platform_time.h"
58 #endif
59 
60 /*
61  * SSL Error codes
62  */
63 #define MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE               -0x7080  /**< The requested feature is not available. */
64 #define MBEDTLS_ERR_SSL_BAD_INPUT_DATA                    -0x7100  /**< Bad input parameters to function. */
65 #define MBEDTLS_ERR_SSL_INVALID_MAC                       -0x7180  /**< Verification of the message MAC failed. */
66 #define MBEDTLS_ERR_SSL_INVALID_RECORD                    -0x7200  /**< An invalid SSL record was received. */
67 #define MBEDTLS_ERR_SSL_CONN_EOF                          -0x7280  /**< The connection indicated an EOF. */
68 #define MBEDTLS_ERR_SSL_UNKNOWN_CIPHER                    -0x7300  /**< An unknown cipher was received. */
69 #define MBEDTLS_ERR_SSL_NO_CIPHER_CHOSEN                  -0x7380  /**< The server has no ciphersuites in common with the client. */
70 #define MBEDTLS_ERR_SSL_NO_RNG                            -0x7400  /**< No RNG was provided to the SSL module. */
71 #define MBEDTLS_ERR_SSL_NO_CLIENT_CERTIFICATE             -0x7480  /**< No client certification received from the client, but required by the authentication mode. */
72 #define MBEDTLS_ERR_SSL_CERTIFICATE_TOO_LARGE             -0x7500  /**< Our own certificate(s) is/are too large to send in an SSL message. */
73 #define MBEDTLS_ERR_SSL_CERTIFICATE_REQUIRED              -0x7580  /**< The own certificate is not set, but needed by the server. */
74 #define MBEDTLS_ERR_SSL_PRIVATE_KEY_REQUIRED              -0x7600  /**< The own private key or pre-shared key is not set, but needed. */
75 #define MBEDTLS_ERR_SSL_CA_CHAIN_REQUIRED                 -0x7680  /**< No CA Chain is set, but required to operate. */
76 #define MBEDTLS_ERR_SSL_UNEXPECTED_MESSAGE                -0x7700  /**< An unexpected message was received from our peer. */
77 #define MBEDTLS_ERR_SSL_FATAL_ALERT_MESSAGE               -0x7780  /**< A fatal alert message was received from our peer. */
78 #define MBEDTLS_ERR_SSL_PEER_VERIFY_FAILED                -0x7800  /**< Verification of our peer failed. */
79 #define MBEDTLS_ERR_SSL_PEER_CLOSE_NOTIFY                 -0x7880  /**< The peer notified us that the connection is going to be closed. */
80 #define MBEDTLS_ERR_SSL_BAD_HS_CLIENT_HELLO               -0x7900  /**< Processing of the ClientHello handshake message failed. */
81 #define MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO               -0x7980  /**< Processing of the ServerHello handshake message failed. */
82 #define MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE                -0x7A00  /**< Processing of the Certificate handshake message failed. */
83 #define MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_REQUEST        -0x7A80  /**< Processing of the CertificateRequest handshake message failed. */
84 #define MBEDTLS_ERR_SSL_BAD_HS_SERVER_KEY_EXCHANGE        -0x7B00  /**< Processing of the ServerKeyExchange handshake message failed. */
85 #define MBEDTLS_ERR_SSL_BAD_HS_SERVER_HELLO_DONE          -0x7B80  /**< Processing of the ServerHelloDone handshake message failed. */
86 #define MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE        -0x7C00  /**< Processing of the ClientKeyExchange handshake message failed. */
87 #define MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_RP     -0x7C80  /**< Processing of the ClientKeyExchange handshake message failed in DHM / ECDH Read Public. */
88 #define MBEDTLS_ERR_SSL_BAD_HS_CLIENT_KEY_EXCHANGE_CS     -0x7D00  /**< Processing of the ClientKeyExchange handshake message failed in DHM / ECDH Calculate Secret. */
89 #define MBEDTLS_ERR_SSL_BAD_HS_CERTIFICATE_VERIFY         -0x7D80  /**< Processing of the CertificateVerify handshake message failed. */
90 #define MBEDTLS_ERR_SSL_BAD_HS_CHANGE_CIPHER_SPEC         -0x7E00  /**< Processing of the ChangeCipherSpec handshake message failed. */
91 #define MBEDTLS_ERR_SSL_BAD_HS_FINISHED                   -0x7E80  /**< Processing of the Finished handshake message failed. */
92 #define MBEDTLS_ERR_SSL_ALLOC_FAILED                      -0x7F00  /**< Memory allocation failed */
93 #define MBEDTLS_ERR_SSL_HW_ACCEL_FAILED                   -0x7F80  /**< Hardware acceleration function returned with error */
94 #define MBEDTLS_ERR_SSL_HW_ACCEL_FALLTHROUGH              -0x6F80  /**< Hardware acceleration function skipped / left alone data */
95 #define MBEDTLS_ERR_SSL_COMPRESSION_FAILED                -0x6F00  /**< Processing of the compression / decompression failed */
96 #define MBEDTLS_ERR_SSL_BAD_HS_PROTOCOL_VERSION           -0x6E80  /**< Handshake protocol not within min/max boundaries */
97 #define MBEDTLS_ERR_SSL_BAD_HS_NEW_SESSION_TICKET         -0x6E00  /**< Processing of the NewSessionTicket handshake message failed. */
98 #define MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED            -0x6D80  /**< Session ticket has expired. */
99 #define MBEDTLS_ERR_SSL_PK_TYPE_MISMATCH                  -0x6D00  /**< Public key type mismatch (eg, asked for RSA key exchange and presented EC key) */
100 #define MBEDTLS_ERR_SSL_UNKNOWN_IDENTITY                  -0x6C80  /**< Unknown identity received (eg, PSK identity) */
101 #define MBEDTLS_ERR_SSL_INTERNAL_ERROR                    -0x6C00  /**< Internal error (eg, unexpected failure in lower-level module) */
102 #define MBEDTLS_ERR_SSL_COUNTER_WRAPPING                  -0x6B80  /**< A counter would wrap (eg, too many messages exchanged). */
103 #define MBEDTLS_ERR_SSL_WAITING_SERVER_HELLO_RENEGO       -0x6B00  /**< Unexpected message at ServerHello in renegotiation. */
104 #define MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED             -0x6A80  /**< DTLS client must retry for hello verification */
105 #define MBEDTLS_ERR_SSL_BUFFER_TOO_SMALL                  -0x6A00  /**< A buffer is too small to receive or write a message */
106 #define MBEDTLS_ERR_SSL_NO_USABLE_CIPHERSUITE             -0x6980  /**< None of the common ciphersuites is usable (eg, no suitable certificate, see debug messages). */
107 #define MBEDTLS_ERR_SSL_WANT_READ                         -0x6900  /**< Connection requires a read call. */
108 #define MBEDTLS_ERR_SSL_WANT_WRITE                        -0x6880  /**< Connection requires a write call. */
109 #define MBEDTLS_ERR_SSL_TIMEOUT                           -0x6800  /**< The operation timed out. */
110 #define MBEDTLS_ERR_SSL_CLIENT_RECONNECT                  -0x6780  /**< The client initiated a reconnect from the same port. */
111 #define MBEDTLS_ERR_SSL_UNEXPECTED_RECORD                 -0x6700  /**< Record header looks valid but is not expected. */
112 #define MBEDTLS_ERR_SSL_NON_FATAL                         -0x6680  /**< The alert message received indicates a non-fatal error. */
113 #define MBEDTLS_ERR_SSL_INVALID_VERIFY_HASH               -0x6600  /**< Couldn't set the hash for verifying CertificateVerify */
114 
115 /*
116  * Various constants
117  */
118 #define MBEDTLS_SSL_MAJOR_VERSION_3             3
119 #define MBEDTLS_SSL_MINOR_VERSION_0             0   /*!< SSL v3.0 */
120 #define MBEDTLS_SSL_MINOR_VERSION_1             1   /*!< TLS v1.0 */
121 #define MBEDTLS_SSL_MINOR_VERSION_2             2   /*!< TLS v1.1 */
122 #define MBEDTLS_SSL_MINOR_VERSION_3             3   /*!< TLS v1.2 */
123 
124 #define MBEDTLS_SSL_TRANSPORT_STREAM            0   /*!< TLS      */
125 #define MBEDTLS_SSL_TRANSPORT_DATAGRAM          1   /*!< DTLS     */
126 
127 #define MBEDTLS_SSL_MAX_HOST_NAME_LEN           255 /*!< Maximum host name defined in RFC 1035 */
128 
129 /* RFC 6066 section 4, see also mfl_code_to_length in ssl_tls.c
130  * NONE must be zero so that memset()ing structure to zero works */
131 #define MBEDTLS_SSL_MAX_FRAG_LEN_NONE           0   /*!< don't use this extension   */
132 #define MBEDTLS_SSL_MAX_FRAG_LEN_512            1   /*!< MaxFragmentLength 2^9      */
133 #define MBEDTLS_SSL_MAX_FRAG_LEN_1024           2   /*!< MaxFragmentLength 2^10     */
134 #define MBEDTLS_SSL_MAX_FRAG_LEN_2048           3   /*!< MaxFragmentLength 2^11     */
135 #define MBEDTLS_SSL_MAX_FRAG_LEN_4096           4   /*!< MaxFragmentLength 2^12     */
136 #define MBEDTLS_SSL_MAX_FRAG_LEN_INVALID        5   /*!< first invalid value        */
137 
138 #define MBEDTLS_SSL_IS_CLIENT                   0
139 #define MBEDTLS_SSL_IS_SERVER                   1
140 
141 #define MBEDTLS_SSL_IS_NOT_FALLBACK             0
142 #define MBEDTLS_SSL_IS_FALLBACK                 1
143 
144 #define MBEDTLS_SSL_EXTENDED_MS_DISABLED        0
145 #define MBEDTLS_SSL_EXTENDED_MS_ENABLED         1
146 
147 #define MBEDTLS_SSL_ETM_DISABLED                0
148 #define MBEDTLS_SSL_ETM_ENABLED                 1
149 
150 #define MBEDTLS_SSL_COMPRESS_NULL               0
151 #define MBEDTLS_SSL_COMPRESS_DEFLATE            1
152 
153 #define MBEDTLS_SSL_VERIFY_NONE                 0
154 #define MBEDTLS_SSL_VERIFY_OPTIONAL             1
155 #define MBEDTLS_SSL_VERIFY_REQUIRED             2
156 #define MBEDTLS_SSL_VERIFY_UNSET                3 /* Used only for sni_authmode */
157 
158 #define MBEDTLS_SSL_LEGACY_RENEGOTIATION        0
159 #define MBEDTLS_SSL_SECURE_RENEGOTIATION        1
160 
161 #define MBEDTLS_SSL_RENEGOTIATION_DISABLED      0
162 #define MBEDTLS_SSL_RENEGOTIATION_ENABLED       1
163 
164 #define MBEDTLS_SSL_ANTI_REPLAY_DISABLED        0
165 #define MBEDTLS_SSL_ANTI_REPLAY_ENABLED         1
166 
167 #define MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED  -1
168 #define MBEDTLS_SSL_RENEGO_MAX_RECORDS_DEFAULT  16
169 
170 #define MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION     0
171 #define MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION  1
172 #define MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE      2
173 
174 #define MBEDTLS_SSL_TRUNC_HMAC_DISABLED         0
175 #define MBEDTLS_SSL_TRUNC_HMAC_ENABLED          1
176 #define MBEDTLS_SSL_TRUNCATED_HMAC_LEN          10  /* 80 bits, rfc 6066 section 7 */
177 
178 #define MBEDTLS_SSL_SESSION_TICKETS_DISABLED     0
179 #define MBEDTLS_SSL_SESSION_TICKETS_ENABLED      1
180 
181 #define MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED    0
182 #define MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED     1
183 
184 #define MBEDTLS_SSL_ARC4_ENABLED                0
185 #define MBEDTLS_SSL_ARC4_DISABLED               1
186 
187 #define MBEDTLS_SSL_PRESET_DEFAULT              0
188 #define MBEDTLS_SSL_PRESET_SUITEB               2
189 
190 #define MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED       1
191 #define MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED      0
192 
193 /*
194  * Default range for DTLS retransmission timer value, in milliseconds.
195  * RFC 6347 4.2.4.1 says from 1 second to 60 seconds.
196  */
197 #define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MIN    1000
198 #define MBEDTLS_SSL_DTLS_TIMEOUT_DFL_MAX   60000
199 
200 /**
201  * \name SECTION: Module settings
202  *
203  * The configuration options you can set for this module are in this section.
204  * Either change them in config.h or define them on the compiler command line.
205  * \{
206  */
207 
208 #if !defined(MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME)
209 #define MBEDTLS_SSL_DEFAULT_TICKET_LIFETIME     86400 /**< Lifetime of session tickets (if enabled) */
210 #endif
211 
212 /*
213  * Maxium fragment length in bytes,
214  * determines the size of each of the two internal I/O buffers.
215  *
216  * Note: the RFC defines the default size of SSL / TLS messages. If you
217  * change the value here, other clients / servers may not be able to
218  * communicate with you anymore. Only change this value if you control
219  * both sides of the connection and have it reduced at both sides, or
220  * if you're using the Max Fragment Length extension and you know all your
221  * peers are using it too!
222  */
223 #if !defined(MBEDTLS_SSL_MAX_CONTENT_LEN)
224 #define MBEDTLS_SSL_MAX_CONTENT_LEN         16384   /**< Size of the input / output buffer */
225 #endif
226 
227 /* \} name SECTION: Module settings */
228 
229 /*
230  * Length of the verify data for secure renegotiation
231  */
232 #if defined(MBEDTLS_SSL_PROTO_SSL3)
233 #define MBEDTLS_SSL_VERIFY_DATA_MAX_LEN 36
234 #else
235 #define MBEDTLS_SSL_VERIFY_DATA_MAX_LEN 12
236 #endif
237 
238 /*
239  * Signaling ciphersuite values (SCSV)
240  */
241 #define MBEDTLS_SSL_EMPTY_RENEGOTIATION_INFO    0xFF   /**< renegotiation info ext */
242 #define MBEDTLS_SSL_FALLBACK_SCSV_VALUE         0x5600 /**< RFC 7507 section 2 */
243 
244 /*
245  * Supported Signature and Hash algorithms (For TLS 1.2)
246  * RFC 5246 section 7.4.1.4.1
247  */
248 #define MBEDTLS_SSL_HASH_NONE                0
249 #define MBEDTLS_SSL_HASH_MD5                 1
250 #define MBEDTLS_SSL_HASH_SHA1                2
251 #define MBEDTLS_SSL_HASH_SHA224              3
252 #define MBEDTLS_SSL_HASH_SHA256              4
253 #define MBEDTLS_SSL_HASH_SHA384              5
254 #define MBEDTLS_SSL_HASH_SHA512              6
255 
256 #define MBEDTLS_SSL_SIG_ANON                 0
257 #define MBEDTLS_SSL_SIG_RSA                  1
258 #define MBEDTLS_SSL_SIG_ECDSA                3
259 
260 /*
261  * Client Certificate Types
262  * RFC 5246 section 7.4.4 plus RFC 4492 section 5.5
263  */
264 #define MBEDTLS_SSL_CERT_TYPE_RSA_SIGN       1
265 #define MBEDTLS_SSL_CERT_TYPE_ECDSA_SIGN    64
266 
267 /*
268  * Message, alert and handshake types
269  */
270 #define MBEDTLS_SSL_MSG_CHANGE_CIPHER_SPEC     20
271 #define MBEDTLS_SSL_MSG_ALERT                  21
272 #define MBEDTLS_SSL_MSG_HANDSHAKE              22
273 #define MBEDTLS_SSL_MSG_APPLICATION_DATA       23
274 
275 #define MBEDTLS_SSL_ALERT_LEVEL_WARNING         1
276 #define MBEDTLS_SSL_ALERT_LEVEL_FATAL           2
277 
278 #define MBEDTLS_SSL_ALERT_MSG_CLOSE_NOTIFY           0  /* 0x00 */
279 #define MBEDTLS_SSL_ALERT_MSG_UNEXPECTED_MESSAGE    10  /* 0x0A */
280 #define MBEDTLS_SSL_ALERT_MSG_BAD_RECORD_MAC        20  /* 0x14 */
281 #define MBEDTLS_SSL_ALERT_MSG_DECRYPTION_FAILED     21  /* 0x15 */
282 #define MBEDTLS_SSL_ALERT_MSG_RECORD_OVERFLOW       22  /* 0x16 */
283 #define MBEDTLS_SSL_ALERT_MSG_DECOMPRESSION_FAILURE 30  /* 0x1E */
284 #define MBEDTLS_SSL_ALERT_MSG_HANDSHAKE_FAILURE     40  /* 0x28 */
285 #define MBEDTLS_SSL_ALERT_MSG_NO_CERT               41  /* 0x29 */
286 #define MBEDTLS_SSL_ALERT_MSG_BAD_CERT              42  /* 0x2A */
287 #define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_CERT      43  /* 0x2B */
288 #define MBEDTLS_SSL_ALERT_MSG_CERT_REVOKED          44  /* 0x2C */
289 #define MBEDTLS_SSL_ALERT_MSG_CERT_EXPIRED          45  /* 0x2D */
290 #define MBEDTLS_SSL_ALERT_MSG_CERT_UNKNOWN          46  /* 0x2E */
291 #define MBEDTLS_SSL_ALERT_MSG_ILLEGAL_PARAMETER     47  /* 0x2F */
292 #define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_CA            48  /* 0x30 */
293 #define MBEDTLS_SSL_ALERT_MSG_ACCESS_DENIED         49  /* 0x31 */
294 #define MBEDTLS_SSL_ALERT_MSG_DECODE_ERROR          50  /* 0x32 */
295 #define MBEDTLS_SSL_ALERT_MSG_DECRYPT_ERROR         51  /* 0x33 */
296 #define MBEDTLS_SSL_ALERT_MSG_EXPORT_RESTRICTION    60  /* 0x3C */
297 #define MBEDTLS_SSL_ALERT_MSG_PROTOCOL_VERSION      70  /* 0x46 */
298 #define MBEDTLS_SSL_ALERT_MSG_INSUFFICIENT_SECURITY 71  /* 0x47 */
299 #define MBEDTLS_SSL_ALERT_MSG_INTERNAL_ERROR        80  /* 0x50 */
300 #define MBEDTLS_SSL_ALERT_MSG_INAPROPRIATE_FALLBACK 86  /* 0x56 */
301 #define MBEDTLS_SSL_ALERT_MSG_USER_CANCELED         90  /* 0x5A */
302 #define MBEDTLS_SSL_ALERT_MSG_NO_RENEGOTIATION     100  /* 0x64 */
303 #define MBEDTLS_SSL_ALERT_MSG_UNSUPPORTED_EXT      110  /* 0x6E */
304 #define MBEDTLS_SSL_ALERT_MSG_UNRECOGNIZED_NAME    112  /* 0x70 */
305 #define MBEDTLS_SSL_ALERT_MSG_UNKNOWN_PSK_IDENTITY 115  /* 0x73 */
306 #define MBEDTLS_SSL_ALERT_MSG_NO_APPLICATION_PROTOCOL 120 /* 0x78 */
307 
308 #define MBEDTLS_SSL_HS_HELLO_REQUEST            0
309 #define MBEDTLS_SSL_HS_CLIENT_HELLO             1
310 #define MBEDTLS_SSL_HS_SERVER_HELLO             2
311 #define MBEDTLS_SSL_HS_HELLO_VERIFY_REQUEST     3
312 #define MBEDTLS_SSL_HS_NEW_SESSION_TICKET       4
313 #define MBEDTLS_SSL_HS_CERTIFICATE             11
314 #define MBEDTLS_SSL_HS_SERVER_KEY_EXCHANGE     12
315 #define MBEDTLS_SSL_HS_CERTIFICATE_REQUEST     13
316 #define MBEDTLS_SSL_HS_SERVER_HELLO_DONE       14
317 #define MBEDTLS_SSL_HS_CERTIFICATE_VERIFY      15
318 #define MBEDTLS_SSL_HS_CLIENT_KEY_EXCHANGE     16
319 #define MBEDTLS_SSL_HS_FINISHED                20
320 
321 /*
322  * TLS extensions
323  */
324 #define MBEDTLS_TLS_EXT_SERVERNAME                   0
325 #define MBEDTLS_TLS_EXT_SERVERNAME_HOSTNAME          0
326 
327 #define MBEDTLS_TLS_EXT_MAX_FRAGMENT_LENGTH          1
328 
329 #define MBEDTLS_TLS_EXT_TRUNCATED_HMAC               4
330 
331 #define MBEDTLS_TLS_EXT_SUPPORTED_ELLIPTIC_CURVES   10
332 #define MBEDTLS_TLS_EXT_SUPPORTED_POINT_FORMATS     11
333 
334 #define MBEDTLS_TLS_EXT_SIG_ALG                     13
335 
336 #define MBEDTLS_TLS_EXT_ALPN                        16
337 
338 #define MBEDTLS_TLS_EXT_ENCRYPT_THEN_MAC            22 /* 0x16 */
339 #define MBEDTLS_TLS_EXT_EXTENDED_MASTER_SECRET  0x0017 /* 23 */
340 
341 #define MBEDTLS_TLS_EXT_SESSION_TICKET              35
342 
343 #define MBEDTLS_TLS_EXT_ECJPAKE_KKPP               256 /* experimental */
344 
345 #define MBEDTLS_TLS_EXT_RENEGOTIATION_INFO      0xFF01
346 
347 /*
348  * Size defines
349  */
350 #if !defined(MBEDTLS_PSK_MAX_LEN)
351 #define MBEDTLS_PSK_MAX_LEN            32 /* 256 bits */
352 #endif
353 
354 /* Dummy type used only for its size */
355 union mbedtls_ssl_premaster_secret
356 {
357 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_ENABLED)
358     unsigned char _pms_rsa[48];                         /* RFC 5246 8.1.1 */
359 #endif
360 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_RSA_ENABLED)
361     unsigned char _pms_dhm[MBEDTLS_MPI_MAX_SIZE];      /* RFC 5246 8.1.2 */
362 #endif
363 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED)    || \
364     defined(MBEDTLS_KEY_EXCHANGE_ECDHE_ECDSA_ENABLED)  || \
365     defined(MBEDTLS_KEY_EXCHANGE_ECDH_RSA_ENABLED)     || \
366     defined(MBEDTLS_KEY_EXCHANGE_ECDH_ECDSA_ENABLED)
367     unsigned char _pms_ecdh[MBEDTLS_ECP_MAX_BYTES];    /* RFC 4492 5.10 */
368 #endif
369 #if defined(MBEDTLS_KEY_EXCHANGE_PSK_ENABLED)
370     unsigned char _pms_psk[4 + 2 * MBEDTLS_PSK_MAX_LEN];       /* RFC 4279 2 */
371 #endif
372 #if defined(MBEDTLS_KEY_EXCHANGE_DHE_PSK_ENABLED)
373     unsigned char _pms_dhe_psk[4 + MBEDTLS_MPI_MAX_SIZE
374                                  + MBEDTLS_PSK_MAX_LEN];       /* RFC 4279 3 */
375 #endif
376 #if defined(MBEDTLS_KEY_EXCHANGE_RSA_PSK_ENABLED)
377     unsigned char _pms_rsa_psk[52 + MBEDTLS_PSK_MAX_LEN];      /* RFC 4279 4 */
378 #endif
379 #if defined(MBEDTLS_KEY_EXCHANGE_ECDHE_PSK_ENABLED)
380     unsigned char _pms_ecdhe_psk[4 + MBEDTLS_ECP_MAX_BYTES
381                                    + MBEDTLS_PSK_MAX_LEN];     /* RFC 5489 2 */
382 #endif
383 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
384     unsigned char _pms_ecjpake[32];     /* Thread spec: SHA-256 output */
385 #endif
386 };
387 
388 #define MBEDTLS_PREMASTER_SIZE     sizeof( union mbedtls_ssl_premaster_secret )
389 
390 #ifdef __cplusplus
391 extern "C" {
392 #endif
393 
394 /*
395  * SSL state machine
396  */
397 typedef enum
398 {
399     MBEDTLS_SSL_HELLO_REQUEST,
400     MBEDTLS_SSL_CLIENT_HELLO,
401     MBEDTLS_SSL_SERVER_HELLO,
402     MBEDTLS_SSL_SERVER_CERTIFICATE,
403     MBEDTLS_SSL_SERVER_KEY_EXCHANGE,
404     MBEDTLS_SSL_CERTIFICATE_REQUEST,
405     MBEDTLS_SSL_SERVER_HELLO_DONE,
406     MBEDTLS_SSL_CLIENT_CERTIFICATE,
407     MBEDTLS_SSL_CLIENT_KEY_EXCHANGE,
408     MBEDTLS_SSL_CERTIFICATE_VERIFY,
409     MBEDTLS_SSL_CLIENT_CHANGE_CIPHER_SPEC,
410     MBEDTLS_SSL_CLIENT_FINISHED,
411     MBEDTLS_SSL_SERVER_CHANGE_CIPHER_SPEC,
412     MBEDTLS_SSL_SERVER_FINISHED,
413     MBEDTLS_SSL_FLUSH_BUFFERS,
414     MBEDTLS_SSL_HANDSHAKE_WRAPUP,
415     MBEDTLS_SSL_HANDSHAKE_OVER,
416     MBEDTLS_SSL_SERVER_NEW_SESSION_TICKET,
417     MBEDTLS_SSL_SERVER_HELLO_VERIFY_REQUEST_SENT,
418 }
419 mbedtls_ssl_states;
420 
421 /**
422  * \brief          Callback type: send data on the network.
423  *
424  * \note           That callback may be either blocking or non-blocking.
425  *
426  * \param ctx      Context for the send callback (typically a file descriptor)
427  * \param buf      Buffer holding the data to send
428  * \param len      Length of the data to send
429  *
430  * \return         The callback must return the number of bytes sent if any,
431  *                 or a non-zero error code.
432  *                 If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_WRITE
433  *                 must be returned when the operation would block.
434  *
435  * \note           The callback is allowed to send fewer bytes than requested.
436  *                 It must always return the number of bytes actually sent.
437  */
438 typedef int mbedtls_ssl_send_t( void *ctx,
439                                 const unsigned char *buf,
440                                 size_t len );
441 
442 /**
443  * \brief          Callback type: receive data from the network.
444  *
445  * \note           That callback may be either blocking or non-blocking.
446  *
447  * \param ctx      Context for the receive callback (typically a file
448  *                 descriptor)
449  * \param buf      Buffer to write the received data to
450  * \param len      Length of the receive buffer
451  *
452  * \return         The callback must return the number of bytes received,
453  *                 or a non-zero error code.
454  *                 If performing non-blocking I/O, \c MBEDTLS_ERR_SSL_WANT_READ
455  *                 must be returned when the operation would block.
456  *
457  * \note           The callback may receive fewer bytes than the length of the
458  *                 buffer. It must always return the number of bytes actually
459  *                 received and written to the buffer.
460  */
461 typedef int mbedtls_ssl_recv_t( void *ctx,
462                                 unsigned char *buf,
463                                 size_t len );
464 
465 /**
466  * \brief          Callback type: receive data from the network, with timeout
467  *
468  * \note           That callback must block until data is received, or the
469  *                 timeout delay expires, or the operation is interrupted by a
470  *                 signal.
471  *
472  * \param ctx      Context for the receive callback (typically a file descriptor)
473  * \param buf      Buffer to write the received data to
474  * \param len      Length of the receive buffer
475  * \param timeout  Maximum nomber of millisecondes to wait for data
476  *                 0 means no timeout (potentially waiting forever)
477  *
478  * \return         The callback must return the number of bytes received,
479  *                 or a non-zero error code:
480  *                 \c MBEDTLS_ERR_SSL_TIMEOUT if the operation timed out,
481  *                 \c MBEDTLS_ERR_SSL_WANT_READ if interrupted by a signal.
482  *
483  * \note           The callback may receive fewer bytes than the length of the
484  *                 buffer. It must always return the number of bytes actually
485  *                 received and written to the buffer.
486  */
487 typedef int mbedtls_ssl_recv_timeout_t( void *ctx,
488                                         unsigned char *buf,
489                                         size_t len,
490                                         uint32_t timeout );
491 /**
492  * \brief          Callback type: set a pair of timers/delays to watch
493  *
494  * \param ctx      Context pointer
495  * \param int_ms   Intermediate delay in milliseconds
496  * \param fin_ms   Final delay in milliseconds
497  *                 0 cancels the current timer.
498  *
499  * \note           This callback must at least store the necessary information
500  *                 for the associated \c mbedtls_ssl_get_timer_t callback to
501  *                 return correct information.
502  *
503  * \note           If using a event-driven style of programming, an event must
504  *                 be generated when the final delay is passed. The event must
505  *                 cause a call to \c mbedtls_ssl_handshake() with the proper
506  *                 SSL context to be scheduled. Care must be taken to ensure
507  *                 that at most one such call happens at a time.
508  *
509  * \note           Only one timer at a time must be running. Calling this
510  *                 function while a timer is running must cancel it. Cancelled
511  *                 timers must not generate any event.
512  */
513 typedef void mbedtls_ssl_set_timer_t( void * ctx,
514                                       uint32_t int_ms,
515                                       uint32_t fin_ms );
516 
517 /**
518  * \brief          Callback type: get status of timers/delays
519  *
520  * \param ctx      Context pointer
521  *
522  * \return         This callback must return:
523  *                 -1 if cancelled (fin_ms == 0),
524  *                  0 if none of the delays have passed,
525  *                  1 if only the intermediate delay has passed,
526  *                  2 if the final delay has passed.
527  */
528 typedef int mbedtls_ssl_get_timer_t( void * ctx );
529 
530 
531 /* Defined below */
532 typedef struct mbedtls_ssl_session mbedtls_ssl_session;
533 typedef struct mbedtls_ssl_context mbedtls_ssl_context;
534 typedef struct mbedtls_ssl_config  mbedtls_ssl_config;
535 
536 /* Defined in ssl_internal.h */
537 typedef struct mbedtls_ssl_transform mbedtls_ssl_transform;
538 typedef struct mbedtls_ssl_handshake_params mbedtls_ssl_handshake_params;
539 typedef struct mbedtls_ssl_sig_hash_set_t mbedtls_ssl_sig_hash_set_t;
540 #if defined(MBEDTLS_X509_CRT_PARSE_C)
541 typedef struct mbedtls_ssl_key_cert mbedtls_ssl_key_cert;
542 #endif
543 #if defined(MBEDTLS_SSL_PROTO_DTLS)
544 typedef struct mbedtls_ssl_flight_item mbedtls_ssl_flight_item;
545 #endif
546 
547 /*
548  * This structure is used for storing current session data.
549  */
550 struct mbedtls_ssl_session
551 {
552 #if defined(MBEDTLS_HAVE_TIME)
553     mbedtls_time_t start;       /*!< starting time      */
554 #endif
555     int ciphersuite;            /*!< chosen ciphersuite */
556     int compression;            /*!< chosen compression */
557     size_t id_len;              /*!< session id length  */
558     unsigned char id[32];       /*!< session identifier */
559     unsigned char master[48];   /*!< the master secret  */
560 
561 #if defined(MBEDTLS_X509_CRT_PARSE_C)
562     mbedtls_x509_crt *peer_cert;        /*!< peer X.509 cert chain */
563 #endif /* MBEDTLS_X509_CRT_PARSE_C */
564     uint32_t verify_result;          /*!<  verification result     */
565 
566 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
567     unsigned char *ticket;      /*!< RFC 5077 session ticket */
568     size_t ticket_len;          /*!< session ticket length   */
569     uint32_t ticket_lifetime;   /*!< ticket lifetime hint    */
570 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
571 
572 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
573     unsigned char mfl_code;     /*!< MaxFragmentLength negotiated by peer */
574 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
575 
576 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
577     int trunc_hmac;             /*!< flag for truncated hmac activation   */
578 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
579 
580 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
581     int encrypt_then_mac;       /*!< flag for EtM activation                */
582 #endif
583 };
584 
585 /**
586  * SSL/TLS configuration to be shared between mbedtls_ssl_context structures.
587  */
588 struct mbedtls_ssl_config
589 {
590     /* Group items by size (largest first) to minimize padding overhead */
591 
592     /*
593      * Pointers
594      */
595 
596     const int *ciphersuite_list[4]; /*!< allowed ciphersuites per version   */
597 
598     /** Callback for printing debug output                                  */
599     void (*f_dbg)(void *, int, const char *, int, const char *);
600     void *p_dbg;                    /*!< context for the debug function     */
601 
602     /** Callback for getting (pseudo-)random numbers                        */
603     int  (*f_rng)(void *, unsigned char *, size_t);
604     void *p_rng;                    /*!< context for the RNG function       */
605 
606     /** Callback to retrieve a session from the cache                       */
607     int (*f_get_cache)(void *, mbedtls_ssl_session *);
608     /** Callback to store a session into the cache                          */
609     int (*f_set_cache)(void *, const mbedtls_ssl_session *);
610     void *p_cache;                  /*!< context for cache callbacks        */
611 
612 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
613     /** Callback for setting cert according to SNI extension                */
614     int (*f_sni)(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
615     void *p_sni;                    /*!< context for SNI callback           */
616 #endif
617 
618 #if defined(MBEDTLS_X509_CRT_PARSE_C)
619     /** Callback to customize X.509 certificate chain verification          */
620     int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *);
621     void *p_vrfy;                   /*!< context for X.509 verify calllback */
622 #endif
623 
624 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
625     /** Callback to retrieve PSK key from identity                          */
626     int (*f_psk)(void *, mbedtls_ssl_context *, const unsigned char *, size_t);
627     void *p_psk;                    /*!< context for PSK callback           */
628 #endif
629 
630 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
631     /** Callback to create & write a cookie for ClientHello veirifcation    */
632     int (*f_cookie_write)( void *, unsigned char **, unsigned char *,
633                            const unsigned char *, size_t );
634     /** Callback to verify validity of a ClientHello cookie                 */
635     int (*f_cookie_check)( void *, const unsigned char *, size_t,
636                            const unsigned char *, size_t );
637     void *p_cookie;                 /*!< context for the cookie callbacks   */
638 #endif
639 
640 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
641     /** Callback to create & write a session ticket                         */
642     int (*f_ticket_write)( void *, const mbedtls_ssl_session *,
643             unsigned char *, const unsigned char *, size_t *, uint32_t * );
644     /** Callback to parse a session ticket into a session structure         */
645     int (*f_ticket_parse)( void *, mbedtls_ssl_session *, unsigned char *, size_t);
646     void *p_ticket;                 /*!< context for the ticket callbacks   */
647 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
648 
649 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
650     /** Callback to export key block and master secret                      */
651     int (*f_export_keys)( void *, const unsigned char *,
652             const unsigned char *, size_t, size_t, size_t );
653     void *p_export_keys;            /*!< context for key export callback    */
654 #endif
655 
656 #if defined(MBEDTLS_X509_CRT_PARSE_C)
657     const mbedtls_x509_crt_profile *cert_profile; /*!< verification profile */
658     mbedtls_ssl_key_cert *key_cert; /*!< own certificate/key pair(s)        */
659     mbedtls_x509_crt *ca_chain;     /*!< trusted CAs                        */
660     mbedtls_x509_crl *ca_crl;       /*!< trusted CAs CRLs                   */
661 #endif /* MBEDTLS_X509_CRT_PARSE_C */
662 
663 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
664     const int *sig_hashes;          /*!< allowed signature hashes           */
665 #endif
666 
667 #if defined(MBEDTLS_ECP_C)
668     const mbedtls_ecp_group_id *curve_list; /*!< allowed curves             */
669 #endif
670 
671 #if defined(MBEDTLS_DHM_C)
672     mbedtls_mpi dhm_P;              /*!< prime modulus for DHM              */
673     mbedtls_mpi dhm_G;              /*!< generator for DHM                  */
674 #endif
675 
676 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
677     unsigned char *psk;             /*!< pre-shared key                     */
678     size_t         psk_len;         /*!< length of the pre-shared key       */
679     unsigned char *psk_identity;    /*!< identity for PSK negotiation       */
680     size_t         psk_identity_len;/*!< length of identity                 */
681 #endif
682 
683 #if defined(MBEDTLS_SSL_ALPN)
684     const char **alpn_list;         /*!< ordered list of protocols          */
685 #endif
686 
687     /*
688      * Numerical settings (int then char)
689      */
690 
691     uint32_t read_timeout;          /*!< timeout for mbedtls_ssl_read (ms)  */
692 
693 #if defined(MBEDTLS_SSL_PROTO_DTLS)
694     uint32_t hs_timeout_min;        /*!< initial value of the handshake
695                                          retransmission timeout (ms)        */
696     uint32_t hs_timeout_max;        /*!< maximum value of the handshake
697                                          retransmission timeout (ms)        */
698 #endif
699 
700 #if defined(MBEDTLS_SSL_RENEGOTIATION)
701     int renego_max_records;         /*!< grace period for renegotiation     */
702     unsigned char renego_period[8]; /*!< value of the record counters
703                                          that triggers renegotiation        */
704 #endif
705 
706 #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT)
707     unsigned int badmac_limit;      /*!< limit of records with a bad MAC    */
708 #endif
709 
710 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
711     unsigned int dhm_min_bitlen;    /*!< min. bit length of the DHM prime   */
712 #endif
713 
714     unsigned char max_major_ver;    /*!< max. major version used            */
715     unsigned char max_minor_ver;    /*!< max. minor version used            */
716     unsigned char min_major_ver;    /*!< min. major version used            */
717     unsigned char min_minor_ver;    /*!< min. minor version used            */
718 
719     /*
720      * Flags (bitfields)
721      */
722 
723     unsigned int endpoint : 1;      /*!< 0: client, 1: server               */
724     unsigned int transport : 1;     /*!< stream (TLS) or datagram (DTLS)    */
725     unsigned int authmode : 2;      /*!< MBEDTLS_SSL_VERIFY_XXX             */
726     /* needed even with renego disabled for LEGACY_BREAK_HANDSHAKE          */
727     unsigned int allow_legacy_renegotiation : 2 ; /*!< MBEDTLS_LEGACY_XXX   */
728 #if defined(MBEDTLS_ARC4_C)
729     unsigned int arc4_disabled : 1; /*!< blacklist RC4 ciphersuites?        */
730 #endif
731 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
732     unsigned int mfl_code : 3;      /*!< desired fragment length            */
733 #endif
734 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
735     unsigned int encrypt_then_mac : 1 ; /*!< negotiate encrypt-then-mac?    */
736 #endif
737 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
738     unsigned int extended_ms : 1;   /*!< negotiate extended master secret?  */
739 #endif
740 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
741     unsigned int anti_replay : 1;   /*!< detect and prevent replay?         */
742 #endif
743 #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
744     unsigned int cbc_record_splitting : 1;  /*!< do cbc record splitting    */
745 #endif
746 #if defined(MBEDTLS_SSL_RENEGOTIATION)
747     unsigned int disable_renegotiation : 1; /*!< disable renegotiation?     */
748 #endif
749 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
750     unsigned int trunc_hmac : 1;    /*!< negotiate truncated hmac?          */
751 #endif
752 #if defined(MBEDTLS_SSL_SESSION_TICKETS)
753     unsigned int session_tickets : 1;   /*!< use session tickets?           */
754 #endif
755 #if defined(MBEDTLS_SSL_FALLBACK_SCSV) && defined(MBEDTLS_SSL_CLI_C)
756     unsigned int fallback : 1;      /*!< is this a fallback?                */
757 #endif
758 #if defined(MBEDTLS_SSL_SRV_C)
759     unsigned int cert_req_ca_list : 1;  /*!< enable sending CA list in
760                                           Certificate Request messages?     */
761 #endif
762 };
763 
764 
765 struct mbedtls_ssl_context
766 {
767     const mbedtls_ssl_config *conf; /*!< configuration information          */
768 
769     /*
770      * Miscellaneous
771      */
772     int state;                  /*!< SSL handshake: current state     */
773 #if defined(MBEDTLS_SSL_RENEGOTIATION)
774     int renego_status;          /*!< Initial, in progress, pending?   */
775     int renego_records_seen;    /*!< Records since renego request, or with DTLS,
776                                   number of retransmissions of request if
777                                   renego_max_records is < 0           */
778 #endif
779 
780     int major_ver;              /*!< equal to  MBEDTLS_SSL_MAJOR_VERSION_3    */
781     int minor_ver;              /*!< either 0 (SSL3) or 1 (TLS1.0)    */
782 
783 #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT)
784     unsigned badmac_seen;       /*!< records with a bad MAC received    */
785 #endif
786 
787     mbedtls_ssl_send_t *f_send; /*!< Callback for network send */
788     mbedtls_ssl_recv_t *f_recv; /*!< Callback for network receive */
789     mbedtls_ssl_recv_timeout_t *f_recv_timeout;
790                                 /*!< Callback for network receive with timeout */
791 
792     void *p_bio;                /*!< context for I/O operations   */
793 
794     /*
795      * Session layer
796      */
797     mbedtls_ssl_session *session_in;            /*!<  current session data (in)   */
798     mbedtls_ssl_session *session_out;           /*!<  current session data (out)  */
799     mbedtls_ssl_session *session;               /*!<  negotiated session data     */
800     mbedtls_ssl_session *session_negotiate;     /*!<  session data in negotiation */
801 
802     mbedtls_ssl_handshake_params *handshake;    /*!<  params required only during
803                                               the handshake process        */
804 
805     /*
806      * Record layer transformations
807      */
808     mbedtls_ssl_transform *transform_in;        /*!<  current transform params (in)   */
809     mbedtls_ssl_transform *transform_out;       /*!<  current transform params (in)   */
810     mbedtls_ssl_transform *transform;           /*!<  negotiated transform params     */
811     mbedtls_ssl_transform *transform_negotiate; /*!<  transform params in negotiation */
812 
813     /*
814      * Timers
815      */
816     void *p_timer;              /*!< context for the timer callbacks */
817 
818     mbedtls_ssl_set_timer_t *f_set_timer;       /*!< set timer callback */
819     mbedtls_ssl_get_timer_t *f_get_timer;       /*!< get timer callback */
820 
821     /*
822      * Record layer (incoming data)
823      */
824     unsigned char *in_buf;      /*!< input buffer                     */
825     unsigned char *in_ctr;      /*!< 64-bit incoming message counter
826                                      TLS: maintained by us
827                                      DTLS: read from peer             */
828     unsigned char *in_hdr;      /*!< start of record header           */
829     unsigned char *in_len;      /*!< two-bytes message length field   */
830     unsigned char *in_iv;       /*!< ivlen-byte IV                    */
831     unsigned char *in_msg;      /*!< message contents (in_iv+ivlen)   */
832     unsigned char *in_offt;     /*!< read offset in application data  */
833 
834     int in_msgtype;             /*!< record header: message type      */
835     size_t in_msglen;           /*!< record header: message length    */
836     size_t in_left;             /*!< amount of data read so far       */
837 #if defined(MBEDTLS_SSL_PROTO_DTLS)
838     uint16_t in_epoch;          /*!< DTLS epoch for incoming records  */
839     size_t next_record_offset;  /*!< offset of the next record in datagram
840                                      (equal to in_left if none)       */
841 #endif
842 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
843     uint64_t in_window_top;     /*!< last validated record seq_num    */
844     uint64_t in_window;         /*!< bitmask for replay detection     */
845 #endif
846 
847     size_t in_hslen;            /*!< current handshake message length,
848                                      including the handshake header   */
849     int nb_zero;                /*!< # of 0-length encrypted messages */
850 
851     int keep_current_message;   /*!< drop or reuse current message
852                                      on next call to record layer? */
853 
854     /*
855      * Record layer (outgoing data)
856      */
857     unsigned char *out_buf;     /*!< output buffer                    */
858     unsigned char *out_ctr;     /*!< 64-bit outgoing message counter  */
859     unsigned char *out_hdr;     /*!< start of record header           */
860     unsigned char *out_len;     /*!< two-bytes message length field   */
861     unsigned char *out_iv;      /*!< ivlen-byte IV                    */
862     unsigned char *out_msg;     /*!< message contents (out_iv+ivlen)  */
863 
864     int out_msgtype;            /*!< record header: message type      */
865     size_t out_msglen;          /*!< record header: message length    */
866     size_t out_left;            /*!< amount of data not yet written   */
867 
868 #if defined(MBEDTLS_ZLIB_SUPPORT)
869     unsigned char *compress_buf;        /*!<  zlib data buffer        */
870 #endif
871 #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
872     signed char split_done;     /*!< current record already splitted? */
873 #endif
874 
875     /*
876      * PKI layer
877      */
878     int client_auth;                    /*!<  flag for client auth.   */
879 
880     /*
881      * User settings
882      */
883 #if defined(MBEDTLS_X509_CRT_PARSE_C)
884     char *hostname;             /*!< expected peer CN for verification
885                                      (and SNI if available)                 */
886 #endif
887 
888 #if defined(MBEDTLS_SSL_ALPN)
889     const char *alpn_chosen;    /*!<  negotiated protocol                   */
890 #endif
891 
892     /*
893      * Information for DTLS hello verify
894      */
895 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
896     unsigned char  *cli_id;         /*!<  transport-level ID of the client  */
897     size_t          cli_id_len;     /*!<  length of cli_id                  */
898 #endif
899 
900     /*
901      * Secure renegotiation
902      */
903     /* needed to know when to send extension on server */
904     int secure_renegotiation;           /*!<  does peer support legacy or
905                                               secure renegotiation           */
906 #if defined(MBEDTLS_SSL_RENEGOTIATION)
907     size_t verify_data_len;             /*!<  length of verify data stored   */
908     char own_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
909     char peer_verify_data[MBEDTLS_SSL_VERIFY_DATA_MAX_LEN]; /*!<  previous handshake verify data */
910 #endif
911 };
912 
913 #if defined(MBEDTLS_SSL_HW_RECORD_ACCEL)
914 
915 #define MBEDTLS_SSL_CHANNEL_OUTBOUND    0
916 #define MBEDTLS_SSL_CHANNEL_INBOUND     1
917 
918 extern int (*mbedtls_ssl_hw_record_init)(mbedtls_ssl_context *ssl,
919                 const unsigned char *key_enc, const unsigned char *key_dec,
920                 size_t keylen,
921                 const unsigned char *iv_enc,  const unsigned char *iv_dec,
922                 size_t ivlen,
923                 const unsigned char *mac_enc, const unsigned char *mac_dec,
924                 size_t maclen);
925 extern int (*mbedtls_ssl_hw_record_activate)(mbedtls_ssl_context *ssl, int direction);
926 extern int (*mbedtls_ssl_hw_record_reset)(mbedtls_ssl_context *ssl);
927 extern int (*mbedtls_ssl_hw_record_write)(mbedtls_ssl_context *ssl);
928 extern int (*mbedtls_ssl_hw_record_read)(mbedtls_ssl_context *ssl);
929 extern int (*mbedtls_ssl_hw_record_finish)(mbedtls_ssl_context *ssl);
930 #endif /* MBEDTLS_SSL_HW_RECORD_ACCEL */
931 
932 /**
933  * \brief Returns the list of ciphersuites supported by the SSL/TLS module.
934  *
935  * \return              a statically allocated array of ciphersuites, the last
936  *                      entry is 0.
937  */
938 const int *mbedtls_ssl_list_ciphersuites( void );
939 
940 /**
941  * \brief               Return the name of the ciphersuite associated with the
942  *                      given ID
943  *
944  * \param ciphersuite_id SSL ciphersuite ID
945  *
946  * \return              a string containing the ciphersuite name
947  */
948 const char *mbedtls_ssl_get_ciphersuite_name( const int ciphersuite_id );
949 
950 /**
951  * \brief               Return the ID of the ciphersuite associated with the
952  *                      given name
953  *
954  * \param ciphersuite_name SSL ciphersuite name
955  *
956  * \return              the ID with the ciphersuite or 0 if not found
957  */
958 int mbedtls_ssl_get_ciphersuite_id( const char *ciphersuite_name );
959 
960 /**
961  * \brief          Initialize an SSL context
962  *                 Just makes the context ready for mbedtls_ssl_setup() or
963  *                 mbedtls_ssl_free()
964  *
965  * \param ssl      SSL context
966  */
967 void mbedtls_ssl_init( mbedtls_ssl_context *ssl );
968 
969 /**
970  * \brief          Set up an SSL context for use
971  *
972  * \note           No copy of the configuration context is made, it can be
973  *                 shared by many mbedtls_ssl_context structures.
974  *
975  * \warning        Modifying the conf structure after it has been used in this
976  *                 function is unsupported!
977  *
978  * \param ssl      SSL context
979  * \param conf     SSL configuration to use
980  *
981  * \return         0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED if
982  *                 memory allocation failed
983  */
984 int mbedtls_ssl_setup( mbedtls_ssl_context *ssl,
985                        const mbedtls_ssl_config *conf );
986 
987 /**
988  * \brief          Reset an already initialized SSL context for re-use
989  *                 while retaining application-set variables, function
990  *                 pointers and data.
991  *
992  * \param ssl      SSL context
993  * \return         0 if successful, or MBEDTLS_ERR_SSL_ALLOC_FAILED,
994                    MBEDTLS_ERR_SSL_HW_ACCEL_FAILED or
995  *                 MBEDTLS_ERR_SSL_COMPRESSION_FAILED
996  */
997 int mbedtls_ssl_session_reset( mbedtls_ssl_context *ssl );
998 
999 /**
1000  * \brief          Set the current endpoint type
1001  *
1002  * \param conf     SSL configuration
1003  * \param endpoint must be MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
1004  */
1005 void mbedtls_ssl_conf_endpoint( mbedtls_ssl_config *conf, int endpoint );
1006 
1007 /**
1008  * \brief           Set the transport type (TLS or DTLS).
1009  *                  Default: TLS
1010  *
1011  * \note            For DTLS, you must either provide a recv callback that
1012  *                  doesn't block, or one that handles timeouts, see
1013  *                  \c mbedtls_ssl_set_bio(). You also need to provide timer
1014  *                  callbacks with \c mbedtls_ssl_set_timer_cb().
1015  *
1016  * \param conf      SSL configuration
1017  * \param transport transport type:
1018  *                  MBEDTLS_SSL_TRANSPORT_STREAM for TLS,
1019  *                  MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS.
1020  */
1021 void mbedtls_ssl_conf_transport( mbedtls_ssl_config *conf, int transport );
1022 
1023 /**
1024  * \brief          Set the certificate verification mode
1025  *                 Default: NONE on server, REQUIRED on client
1026  *
1027  * \param conf     SSL configuration
1028  * \param authmode can be:
1029  *
1030  *  MBEDTLS_SSL_VERIFY_NONE:      peer certificate is not checked
1031  *                        (default on server)
1032  *                        (insecure on client)
1033  *
1034  *  MBEDTLS_SSL_VERIFY_OPTIONAL:  peer certificate is checked, however the
1035  *                        handshake continues even if verification failed;
1036  *                        mbedtls_ssl_get_verify_result() can be called after the
1037  *                        handshake is complete.
1038  *
1039  *  MBEDTLS_SSL_VERIFY_REQUIRED:  peer *must* present a valid certificate,
1040  *                        handshake is aborted if verification failed.
1041  *                        (default on client)
1042  *
1043  * \note On client, MBEDTLS_SSL_VERIFY_REQUIRED is the recommended mode.
1044  * With MBEDTLS_SSL_VERIFY_OPTIONAL, the user needs to call mbedtls_ssl_get_verify_result() at
1045  * the right time(s), which may not be obvious, while REQUIRED always perform
1046  * the verification as soon as possible. For example, REQUIRED was protecting
1047  * against the "triple handshake" attack even before it was found.
1048  */
1049 void mbedtls_ssl_conf_authmode( mbedtls_ssl_config *conf, int authmode );
1050 
1051 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1052 /**
1053  * \brief          Set the verification callback (Optional).
1054  *
1055  *                 If set, the verify callback is called for each
1056  *                 certificate in the chain. For implementation
1057  *                 information, please see \c mbedtls_x509_crt_verify()
1058  *
1059  * \param conf     SSL configuration
1060  * \param f_vrfy   verification function
1061  * \param p_vrfy   verification parameter
1062  */
1063 void mbedtls_ssl_conf_verify( mbedtls_ssl_config *conf,
1064                      int (*f_vrfy)(void *, mbedtls_x509_crt *, int, uint32_t *),
1065                      void *p_vrfy );
1066 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1067 
1068 /**
1069  * \brief          Set the random number generator callback
1070  *
1071  * \param conf     SSL configuration
1072  * \param f_rng    RNG function
1073  * \param p_rng    RNG parameter
1074  */
1075 void mbedtls_ssl_conf_rng( mbedtls_ssl_config *conf,
1076                   int (*f_rng)(void *, unsigned char *, size_t),
1077                   void *p_rng );
1078 
1079 /**
1080  * \brief          Set the debug callback
1081  *
1082  *                 The callback has the following argument:
1083  *                 void *           opaque context for the callback
1084  *                 int              debug level
1085  *                 const char *     file name
1086  *                 int              line number
1087  *                 const char *     message
1088  *
1089  * \param conf     SSL configuration
1090  * \param f_dbg    debug function
1091  * \param p_dbg    debug parameter
1092  */
1093 void mbedtls_ssl_conf_dbg( mbedtls_ssl_config *conf,
1094                   void (*f_dbg)(void *, int, const char *, int, const char *),
1095                   void  *p_dbg );
1096 
1097 /**
1098  * \brief          Set the underlying BIO callbacks for write, read and
1099  *                 read-with-timeout.
1100  *
1101  * \param ssl      SSL context
1102  * \param p_bio    parameter (context) shared by BIO callbacks
1103  * \param f_send   write callback
1104  * \param f_recv   read callback
1105  * \param f_recv_timeout blocking read callback with timeout.
1106  *
1107  * \note           One of f_recv or f_recv_timeout can be NULL, in which case
1108  *                 the other is used. If both are non-NULL, f_recv_timeout is
1109  *                 used and f_recv is ignored (as if it were NULL).
1110  *
1111  * \note           The two most common use cases are:
1112  *                 - non-blocking I/O, f_recv != NULL, f_recv_timeout == NULL
1113  *                 - blocking I/O, f_recv == NULL, f_recv_timout != NULL
1114  *
1115  * \note           For DTLS, you need to provide either a non-NULL
1116  *                 f_recv_timeout callback, or a f_recv that doesn't block.
1117  *
1118  * \note           See the documentations of \c mbedtls_ssl_sent_t,
1119  *                 \c mbedtls_ssl_recv_t and \c mbedtls_ssl_recv_timeout_t for
1120  *                 the conventions those callbacks must follow.
1121  *
1122  * \note           On some platforms, net_sockets.c provides
1123  *                 \c mbedtls_net_send(), \c mbedtls_net_recv() and
1124  *                 \c mbedtls_net_recv_timeout() that are suitable to be used
1125  *                 here.
1126  */
1127 void mbedtls_ssl_set_bio( mbedtls_ssl_context *ssl,
1128                           void *p_bio,
1129                           mbedtls_ssl_send_t *f_send,
1130                           mbedtls_ssl_recv_t *f_recv,
1131                           mbedtls_ssl_recv_timeout_t *f_recv_timeout );
1132 
1133 /**
1134  * \brief          Set the timeout period for mbedtls_ssl_read()
1135  *                 (Default: no timeout.)
1136  *
1137  * \param conf     SSL configuration context
1138  * \param timeout  Timeout value in milliseconds.
1139  *                 Use 0 for no timeout (default).
1140  *
1141  * \note           With blocking I/O, this will only work if a non-NULL
1142  *                 \c f_recv_timeout was set with \c mbedtls_ssl_set_bio().
1143  *                 With non-blocking I/O, this will only work if timer
1144  *                 callbacks were set with \c mbedtls_ssl_set_timer_cb().
1145  *
1146  * \note           With non-blocking I/O, you may also skip this function
1147  *                 altogether and handle timeouts at the application layer.
1148  */
1149 void mbedtls_ssl_conf_read_timeout( mbedtls_ssl_config *conf, uint32_t timeout );
1150 
1151 /**
1152  * \brief          Set the timer callbacks (Mandatory for DTLS.)
1153  *
1154  * \param ssl      SSL context
1155  * \param p_timer  parameter (context) shared by timer callbacks
1156  * \param f_set_timer   set timer callback
1157  * \param f_get_timer   get timer callback. Must return:
1158  *
1159  * \note           See the documentation of \c mbedtls_ssl_set_timer_t and
1160  *                 \c mbedtls_ssl_get_timer_t for the conventions this pair of
1161  *                 callbacks must follow.
1162  *
1163  * \note           On some platforms, timing.c provides
1164  *                 \c mbedtls_timing_set_delay() and
1165  *                 \c mbedtls_timing_get_delay() that are suitable for using
1166  *                 here, except if using an event-driven style.
1167  *
1168  * \note           See also the "DTLS tutorial" article in our knowledge base.
1169  *                 https://tls.mbed.org/kb/how-to/dtls-tutorial
1170  */
1171 void mbedtls_ssl_set_timer_cb( mbedtls_ssl_context *ssl,
1172                                void *p_timer,
1173                                mbedtls_ssl_set_timer_t *f_set_timer,
1174                                mbedtls_ssl_get_timer_t *f_get_timer );
1175 
1176 /**
1177  * \brief           Callback type: generate and write session ticket
1178  *
1179  * \note            This describes what a callback implementation should do.
1180  *                  This callback should generate an encrypted and
1181  *                  authenticated ticket for the session and write it to the
1182  *                  output buffer. Here, ticket means the opaque ticket part
1183  *                  of the NewSessionTicket structure of RFC 5077.
1184  *
1185  * \param p_ticket  Context for the callback
1186  * \param session   SSL session to be written in the ticket
1187  * \param start     Start of the output buffer
1188  * \param end       End of the output buffer
1189  * \param tlen      On exit, holds the length written
1190  * \param lifetime  On exit, holds the lifetime of the ticket in seconds
1191  *
1192  * \return          0 if successful, or
1193  *                  a specific MBEDTLS_ERR_XXX code.
1194  */
1195 typedef int mbedtls_ssl_ticket_write_t( void *p_ticket,
1196                                         const mbedtls_ssl_session *session,
1197                                         unsigned char *start,
1198                                         const unsigned char *end,
1199                                         size_t *tlen,
1200                                         uint32_t *lifetime );
1201 
1202 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
1203 /**
1204  * \brief           Callback type: Export key block and master secret
1205  *
1206  * \note            This is required for certain uses of TLS, e.g. EAP-TLS
1207  *                  (RFC 5216) and Thread. The key pointers are ephemeral and
1208  *                  therefore must not be stored. The master secret and keys
1209  *                  should not be used directly except as an input to a key
1210  *                  derivation function.
1211  *
1212  * \param p_expkey  Context for the callback
1213  * \param ms        Pointer to master secret (fixed length: 48 bytes)
1214  * \param kb        Pointer to key block, see RFC 5246 section 6.3
1215  *                  (variable length: 2 * maclen + 2 * keylen + 2 * ivlen).
1216  * \param maclen    MAC length
1217  * \param keylen    Key length
1218  * \param ivlen     IV length
1219  *
1220  * \return          0 if successful, or
1221  *                  a specific MBEDTLS_ERR_XXX code.
1222  */
1223 typedef int mbedtls_ssl_export_keys_t( void *p_expkey,
1224                                 const unsigned char *ms,
1225                                 const unsigned char *kb,
1226                                 size_t maclen,
1227                                 size_t keylen,
1228                                 size_t ivlen );
1229 #endif /* MBEDTLS_SSL_EXPORT_KEYS */
1230 
1231 /**
1232  * \brief           Callback type: parse and load session ticket
1233  *
1234  * \note            This describes what a callback implementation should do.
1235  *                  This callback should parse a session ticket as generated
1236  *                  by the corresponding mbedtls_ssl_ticket_write_t function,
1237  *                  and, if the ticket is authentic and valid, load the
1238  *                  session.
1239  *
1240  * \note            The implementation is allowed to modify the first len
1241  *                  bytes of the input buffer, eg to use it as a temporary
1242  *                  area for the decrypted ticket contents.
1243  *
1244  * \param p_ticket  Context for the callback
1245  * \param session   SSL session to be loaded
1246  * \param buf       Start of the buffer containing the ticket
1247  * \param len       Length of the ticket.
1248  *
1249  * \return          0 if successful, or
1250  *                  MBEDTLS_ERR_SSL_INVALID_MAC if not authentic, or
1251  *                  MBEDTLS_ERR_SSL_SESSION_TICKET_EXPIRED if expired, or
1252  *                  any other non-zero code for other failures.
1253  */
1254 typedef int mbedtls_ssl_ticket_parse_t( void *p_ticket,
1255                                         mbedtls_ssl_session *session,
1256                                         unsigned char *buf,
1257                                         size_t len );
1258 
1259 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_SRV_C)
1260 /**
1261  * \brief           Configure SSL session ticket callbacks (server only).
1262  *                  (Default: none.)
1263  *
1264  * \note            On server, session tickets are enabled by providing
1265  *                  non-NULL callbacks.
1266  *
1267  * \note            On client, use \c mbedtls_ssl_conf_session_tickets().
1268  *
1269  * \param conf      SSL configuration context
1270  * \param f_ticket_write    Callback for writing a ticket
1271  * \param f_ticket_parse    Callback for parsing a ticket
1272  * \param p_ticket          Context shared by the two callbacks
1273  */
1274 void mbedtls_ssl_conf_session_tickets_cb( mbedtls_ssl_config *conf,
1275         mbedtls_ssl_ticket_write_t *f_ticket_write,
1276         mbedtls_ssl_ticket_parse_t *f_ticket_parse,
1277         void *p_ticket );
1278 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_SRV_C */
1279 
1280 #if defined(MBEDTLS_SSL_EXPORT_KEYS)
1281 /**
1282  * \brief           Configure key export callback.
1283  *                  (Default: none.)
1284  *
1285  * \note            See \c mbedtls_ssl_export_keys_t.
1286  *
1287  * \param conf      SSL configuration context
1288  * \param f_export_keys     Callback for exporting keys
1289  * \param p_export_keys     Context for the callback
1290  */
1291 void mbedtls_ssl_conf_export_keys_cb( mbedtls_ssl_config *conf,
1292         mbedtls_ssl_export_keys_t *f_export_keys,
1293         void *p_export_keys );
1294 #endif /* MBEDTLS_SSL_EXPORT_KEYS */
1295 
1296 /**
1297  * \brief          Callback type: generate a cookie
1298  *
1299  * \param ctx      Context for the callback
1300  * \param p        Buffer to write to,
1301  *                 must be updated to point right after the cookie
1302  * \param end      Pointer to one past the end of the output buffer
1303  * \param info     Client ID info that was passed to
1304  *                 \c mbedtls_ssl_set_client_transport_id()
1305  * \param ilen     Length of info in bytes
1306  *
1307  * \return         The callback must return 0 on success,
1308  *                 or a negative error code.
1309  */
1310 typedef int mbedtls_ssl_cookie_write_t( void *ctx,
1311                                 unsigned char **p, unsigned char *end,
1312                                 const unsigned char *info, size_t ilen );
1313 
1314 /**
1315  * \brief          Callback type: verify a cookie
1316  *
1317  * \param ctx      Context for the callback
1318  * \param cookie   Cookie to verify
1319  * \param clen     Length of cookie
1320  * \param info     Client ID info that was passed to
1321  *                 \c mbedtls_ssl_set_client_transport_id()
1322  * \param ilen     Length of info in bytes
1323  *
1324  * \return         The callback must return 0 if cookie is valid,
1325  *                 or a negative error code.
1326  */
1327 typedef int mbedtls_ssl_cookie_check_t( void *ctx,
1328                                 const unsigned char *cookie, size_t clen,
1329                                 const unsigned char *info, size_t ilen );
1330 
1331 #if defined(MBEDTLS_SSL_DTLS_HELLO_VERIFY) && defined(MBEDTLS_SSL_SRV_C)
1332 /**
1333  * \brief           Register callbacks for DTLS cookies
1334  *                  (Server only. DTLS only.)
1335  *
1336  *                  Default: dummy callbacks that fail, in order to force you to
1337  *                  register working callbacks (and initialize their context).
1338  *
1339  *                  To disable HelloVerifyRequest, register NULL callbacks.
1340  *
1341  * \warning         Disabling hello verification allows your server to be used
1342  *                  for amplification in DoS attacks against other hosts.
1343  *                  Only disable if you known this can't happen in your
1344  *                  particular environment.
1345  *
1346  * \note            See comments on \c mbedtls_ssl_handshake() about handling
1347  *                  the MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED that is expected
1348  *                  on the first handshake attempt when this is enabled.
1349  *
1350  * \note            This is also necessary to handle client reconnection from
1351  *                  the same port as described in RFC 6347 section 4.2.8 (only
1352  *                  the variant with cookies is supported currently). See
1353  *                  comments on \c mbedtls_ssl_read() for details.
1354  *
1355  * \param conf              SSL configuration
1356  * \param f_cookie_write    Cookie write callback
1357  * \param f_cookie_check    Cookie check callback
1358  * \param p_cookie          Context for both callbacks
1359  */
1360 void mbedtls_ssl_conf_dtls_cookies( mbedtls_ssl_config *conf,
1361                            mbedtls_ssl_cookie_write_t *f_cookie_write,
1362                            mbedtls_ssl_cookie_check_t *f_cookie_check,
1363                            void *p_cookie );
1364 
1365 /**
1366  * \brief          Set client's transport-level identification info.
1367  *                 (Server only. DTLS only.)
1368  *
1369  *                 This is usually the IP address (and port), but could be
1370  *                 anything identify the client depending on the underlying
1371  *                 network stack. Used for HelloVerifyRequest with DTLS.
1372  *                 This is *not* used to route the actual packets.
1373  *
1374  * \param ssl      SSL context
1375  * \param info     Transport-level info identifying the client (eg IP + port)
1376  * \param ilen     Length of info in bytes
1377  *
1378  * \note           An internal copy is made, so the info buffer can be reused.
1379  *
1380  * \return         0 on success,
1381  *                 MBEDTLS_ERR_SSL_BAD_INPUT_DATA if used on client,
1382  *                 MBEDTLS_ERR_SSL_ALLOC_FAILED if out of memory.
1383  */
1384 int mbedtls_ssl_set_client_transport_id( mbedtls_ssl_context *ssl,
1385                                  const unsigned char *info,
1386                                  size_t ilen );
1387 
1388 #endif /* MBEDTLS_SSL_DTLS_HELLO_VERIFY && MBEDTLS_SSL_SRV_C */
1389 
1390 #if defined(MBEDTLS_SSL_DTLS_ANTI_REPLAY)
1391 /**
1392  * \brief          Enable or disable anti-replay protection for DTLS.
1393  *                 (DTLS only, no effect on TLS.)
1394  *                 Default: enabled.
1395  *
1396  * \param conf     SSL configuration
1397  * \param mode     MBEDTLS_SSL_ANTI_REPLAY_ENABLED or MBEDTLS_SSL_ANTI_REPLAY_DISABLED.
1398  *
1399  * \warning        Disabling this is a security risk unless the application
1400  *                 protocol handles duplicated packets in a safe way. You
1401  *                 should not disable this without careful consideration.
1402  *                 However, if your application already detects duplicated
1403  *                 packets and needs information about them to adjust its
1404  *                 transmission strategy, then you'll want to disable this.
1405  */
1406 void mbedtls_ssl_conf_dtls_anti_replay( mbedtls_ssl_config *conf, char mode );
1407 #endif /* MBEDTLS_SSL_DTLS_ANTI_REPLAY */
1408 
1409 #if defined(MBEDTLS_SSL_DTLS_BADMAC_LIMIT)
1410 /**
1411  * \brief          Set a limit on the number of records with a bad MAC
1412  *                 before terminating the connection.
1413  *                 (DTLS only, no effect on TLS.)
1414  *                 Default: 0 (disabled).
1415  *
1416  * \param conf     SSL configuration
1417  * \param limit    Limit, or 0 to disable.
1418  *
1419  * \note           If the limit is N, then the connection is terminated when
1420  *                 the Nth non-authentic record is seen.
1421  *
1422  * \note           Records with an invalid header are not counted, only the
1423  *                 ones going through the authentication-decryption phase.
1424  *
1425  * \note           This is a security trade-off related to the fact that it's
1426  *                 often relatively easy for an active attacker ot inject UDP
1427  *                 datagrams. On one hand, setting a low limit here makes it
1428  *                 easier for such an attacker to forcibly terminated a
1429  *                 connection. On the other hand, a high limit or no limit
1430  *                 might make us waste resources checking authentication on
1431  *                 many bogus packets.
1432  */
1433 void mbedtls_ssl_conf_dtls_badmac_limit( mbedtls_ssl_config *conf, unsigned limit );
1434 #endif /* MBEDTLS_SSL_DTLS_BADMAC_LIMIT */
1435 
1436 #if defined(MBEDTLS_SSL_PROTO_DTLS)
1437 /**
1438  * \brief          Set retransmit timeout values for the DTLS handshake.
1439  *                 (DTLS only, no effect on TLS.)
1440  *
1441  * \param conf     SSL configuration
1442  * \param min      Initial timeout value in milliseconds.
1443  *                 Default: 1000 (1 second).
1444  * \param max      Maximum timeout value in milliseconds.
1445  *                 Default: 60000 (60 seconds).
1446  *
1447  * \note           Default values are from RFC 6347 section 4.2.4.1.
1448  *
1449  * \note           The 'min' value should typically be slightly above the
1450  *                 expected round-trip time to your peer, plus whatever time
1451  *                 it takes for the peer to process the message. For example,
1452  *                 if your RTT is about 600ms and you peer needs up to 1s to
1453  *                 do the cryptographic operations in the handshake, then you
1454  *                 should set 'min' slightly above 1600. Lower values of 'min'
1455  *                 might cause spurious resends which waste network resources,
1456  *                 while larger value of 'min' will increase overall latency
1457  *                 on unreliable network links.
1458  *
1459  * \note           The more unreliable your network connection is, the larger
1460  *                 your max / min ratio needs to be in order to achieve
1461  *                 reliable handshakes.
1462  *
1463  * \note           Messages are retransmitted up to log2(ceil(max/min)) times.
1464  *                 For example, if min = 1s and max = 5s, the retransmit plan
1465  *                 goes: send ... 1s -> resend ... 2s -> resend ... 4s ->
1466  *                 resend ... 5s -> give up and return a timeout error.
1467  */
1468 void mbedtls_ssl_conf_handshake_timeout( mbedtls_ssl_config *conf, uint32_t min, uint32_t max );
1469 #endif /* MBEDTLS_SSL_PROTO_DTLS */
1470 
1471 #if defined(MBEDTLS_SSL_SRV_C)
1472 /**
1473  * \brief          Set the session cache callbacks (server-side only)
1474  *                 If not set, no session resuming is done (except if session
1475  *                 tickets are enabled too).
1476  *
1477  *                 The session cache has the responsibility to check for stale
1478  *                 entries based on timeout. See RFC 5246 for recommendations.
1479  *
1480  *                 Warning: session.peer_cert is cleared by the SSL/TLS layer on
1481  *                 connection shutdown, so do not cache the pointer! Either set
1482  *                 it to NULL or make a full copy of the certificate.
1483  *
1484  *                 The get callback is called once during the initial handshake
1485  *                 to enable session resuming. The get function has the
1486  *                 following parameters: (void *parameter, mbedtls_ssl_session *session)
1487  *                 If a valid entry is found, it should fill the master of
1488  *                 the session object with the cached values and return 0,
1489  *                 return 1 otherwise. Optionally peer_cert can be set as well
1490  *                 if it is properly present in cache entry.
1491  *
1492  *                 The set callback is called once during the initial handshake
1493  *                 to enable session resuming after the entire handshake has
1494  *                 been finished. The set function has the following parameters:
1495  *                 (void *parameter, const mbedtls_ssl_session *session). The function
1496  *                 should create a cache entry for future retrieval based on
1497  *                 the data in the session structure and should keep in mind
1498  *                 that the mbedtls_ssl_session object presented (and all its referenced
1499  *                 data) is cleared by the SSL/TLS layer when the connection is
1500  *                 terminated. It is recommended to add metadata to determine if
1501  *                 an entry is still valid in the future. Return 0 if
1502  *                 successfully cached, return 1 otherwise.
1503  *
1504  * \param conf           SSL configuration
1505  * \param p_cache        parmater (context) for both callbacks
1506  * \param f_get_cache    session get callback
1507  * \param f_set_cache    session set callback
1508  */
1509 void mbedtls_ssl_conf_session_cache( mbedtls_ssl_config *conf,
1510         void *p_cache,
1511         int (*f_get_cache)(void *, mbedtls_ssl_session *),
1512         int (*f_set_cache)(void *, const mbedtls_ssl_session *) );
1513 #endif /* MBEDTLS_SSL_SRV_C */
1514 
1515 #if defined(MBEDTLS_SSL_CLI_C)
1516 /**
1517  * \brief          Request resumption of session (client-side only)
1518  *                 Session data is copied from presented session structure.
1519  *
1520  * \param ssl      SSL context
1521  * \param session  session context
1522  *
1523  * \return         0 if successful,
1524  *                 MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed,
1525  *                 MBEDTLS_ERR_SSL_BAD_INPUT_DATA if used server-side or
1526  *                 arguments are otherwise invalid
1527  *
1528  * \sa             mbedtls_ssl_get_session()
1529  */
1530 int mbedtls_ssl_set_session( mbedtls_ssl_context *ssl, const mbedtls_ssl_session *session );
1531 #endif /* MBEDTLS_SSL_CLI_C */
1532 
1533 /**
1534  * \brief               Set the list of allowed ciphersuites and the preference
1535  *                      order. First in the list has the highest preference.
1536  *                      (Overrides all version-specific lists)
1537  *
1538  *                      The ciphersuites array is not copied, and must remain
1539  *                      valid for the lifetime of the ssl_config.
1540  *
1541  *                      Note: The server uses its own preferences
1542  *                      over the preference of the client unless
1543  *                      MBEDTLS_SSL_SRV_RESPECT_CLIENT_PREFERENCE is defined!
1544  *
1545  * \param conf          SSL configuration
1546  * \param ciphersuites  0-terminated list of allowed ciphersuites
1547  */
1548 void mbedtls_ssl_conf_ciphersuites( mbedtls_ssl_config *conf,
1549                                    const int *ciphersuites );
1550 
1551 /**
1552  * \brief               Set the list of allowed ciphersuites and the
1553  *                      preference order for a specific version of the protocol.
1554  *                      (Only useful on the server side)
1555  *
1556  *                      The ciphersuites array is not copied, and must remain
1557  *                      valid for the lifetime of the ssl_config.
1558  *
1559  * \param conf          SSL configuration
1560  * \param ciphersuites  0-terminated list of allowed ciphersuites
1561  * \param major         Major version number (only MBEDTLS_SSL_MAJOR_VERSION_3
1562  *                      supported)
1563  * \param minor         Minor version number (MBEDTLS_SSL_MINOR_VERSION_0,
1564  *                      MBEDTLS_SSL_MINOR_VERSION_1 and MBEDTLS_SSL_MINOR_VERSION_2,
1565  *                      MBEDTLS_SSL_MINOR_VERSION_3 supported)
1566  *
1567  * \note                With DTLS, use MBEDTLS_SSL_MINOR_VERSION_2 for DTLS 1.0
1568  *                      and MBEDTLS_SSL_MINOR_VERSION_3 for DTLS 1.2
1569  */
1570 void mbedtls_ssl_conf_ciphersuites_for_version( mbedtls_ssl_config *conf,
1571                                        const int *ciphersuites,
1572                                        int major, int minor );
1573 
1574 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1575 /**
1576  * \brief          Set the X.509 security profile used for verification
1577  *
1578  * \note           The restrictions are enforced for all certificates in the
1579  *                 chain. However, signatures in the handshake are not covered
1580  *                 by this setting but by \b mbedtls_ssl_conf_sig_hashes().
1581  *
1582  * \param conf     SSL configuration
1583  * \param profile  Profile to use
1584  */
1585 void mbedtls_ssl_conf_cert_profile( mbedtls_ssl_config *conf,
1586                                     const mbedtls_x509_crt_profile *profile );
1587 
1588 /**
1589  * \brief          Set the data required to verify peer certificate
1590  *
1591  * \param conf     SSL configuration
1592  * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
1593  * \param ca_crl   trusted CA CRLs
1594  */
1595 void mbedtls_ssl_conf_ca_chain( mbedtls_ssl_config *conf,
1596                                mbedtls_x509_crt *ca_chain,
1597                                mbedtls_x509_crl *ca_crl );
1598 
1599 /**
1600  * \brief          Set own certificate chain and private key
1601  *
1602  * \note           own_cert should contain in order from the bottom up your
1603  *                 certificate chain. The top certificate (self-signed)
1604  *                 can be omitted.
1605  *
1606  * \note           On server, this function can be called multiple times to
1607  *                 provision more than one cert/key pair (eg one ECDSA, one
1608  *                 RSA with SHA-256, one RSA with SHA-1). An adequate
1609  *                 certificate will be selected according to the client's
1610  *                 advertised capabilities. In case mutliple certificates are
1611  *                 adequate, preference is given to the one set by the first
1612  *                 call to this function, then second, etc.
1613  *
1614  * \note           On client, only the first call has any effect. That is,
1615  *                 only one client certificate can be provisioned. The
1616  *                 server's preferences in its CertficateRequest message will
1617  *                 be ignored and our only cert will be sent regardless of
1618  *                 whether it matches those preferences - the server can then
1619  *                 decide what it wants to do with it.
1620  *
1621  * \param conf     SSL configuration
1622  * \param own_cert own public certificate chain
1623  * \param pk_key   own private key
1624  *
1625  * \return         0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
1626  */
1627 int mbedtls_ssl_conf_own_cert( mbedtls_ssl_config *conf,
1628                               mbedtls_x509_crt *own_cert,
1629                               mbedtls_pk_context *pk_key );
1630 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1631 
1632 #if defined(MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED)
1633 /**
1634  * \brief          Set the Pre Shared Key (PSK) and the expected identity name
1635  *
1636  * \note           This is mainly useful for clients. Servers will usually
1637  *                 want to use \c mbedtls_ssl_conf_psk_cb() instead.
1638  *
1639  * \note           Currently clients can only register one pre-shared key.
1640  *                 In other words, the servers' identity hint is ignored.
1641  *                 Support for setting multiple PSKs on clients and selecting
1642  *                 one based on the identity hint is not a planned feature but
1643  *                 feedback is welcomed.
1644  *
1645  * \param conf     SSL configuration
1646  * \param psk      pointer to the pre-shared key
1647  * \param psk_len  pre-shared key length
1648  * \param psk_identity      pointer to the pre-shared key identity
1649  * \param psk_identity_len  identity key length
1650  *
1651  * \return         0 if successful or MBEDTLS_ERR_SSL_ALLOC_FAILED
1652  */
1653 int mbedtls_ssl_conf_psk( mbedtls_ssl_config *conf,
1654                 const unsigned char *psk, size_t psk_len,
1655                 const unsigned char *psk_identity, size_t psk_identity_len );
1656 
1657 
1658 /**
1659  * \brief          Set the Pre Shared Key (PSK) for the current handshake
1660  *
1661  * \note           This should only be called inside the PSK callback,
1662  *                 ie the function passed to \c mbedtls_ssl_conf_psk_cb().
1663  *
1664  * \param ssl      SSL context
1665  * \param psk      pointer to the pre-shared key
1666  * \param psk_len  pre-shared key length
1667  *
1668  * \return         0 if successful or MBEDTLS_ERR_SSL_ALLOC_FAILED
1669  */
1670 int mbedtls_ssl_set_hs_psk( mbedtls_ssl_context *ssl,
1671                             const unsigned char *psk, size_t psk_len );
1672 
1673 /**
1674  * \brief          Set the PSK callback (server-side only).
1675  *
1676  *                 If set, the PSK callback is called for each
1677  *                 handshake where a PSK ciphersuite was negotiated.
1678  *                 The caller provides the identity received and wants to
1679  *                 receive the actual PSK data and length.
1680  *
1681  *                 The callback has the following parameters: (void *parameter,
1682  *                 mbedtls_ssl_context *ssl, const unsigned char *psk_identity,
1683  *                 size_t identity_len)
1684  *                 If a valid PSK identity is found, the callback should use
1685  *                 \c mbedtls_ssl_set_hs_psk() on the ssl context to set the
1686  *                 correct PSK and return 0.
1687  *                 Any other return value will result in a denied PSK identity.
1688  *
1689  * \note           If you set a PSK callback using this function, then you
1690  *                 don't need to set a PSK key and identity using
1691  *                 \c mbedtls_ssl_conf_psk().
1692  *
1693  * \param conf     SSL configuration
1694  * \param f_psk    PSK identity function
1695  * \param p_psk    PSK identity parameter
1696  */
1697 void mbedtls_ssl_conf_psk_cb( mbedtls_ssl_config *conf,
1698                      int (*f_psk)(void *, mbedtls_ssl_context *, const unsigned char *,
1699                                   size_t),
1700                      void *p_psk );
1701 #endif /* MBEDTLS_KEY_EXCHANGE__SOME__PSK_ENABLED */
1702 
1703 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_SRV_C)
1704 /**
1705  * \brief          Set the Diffie-Hellman public P and G values,
1706  *                 read as hexadecimal strings (server-side only)
1707  *                 (Default: MBEDTLS_DHM_RFC5114_MODP_2048_[PG])
1708  *
1709  * \param conf     SSL configuration
1710  * \param dhm_P    Diffie-Hellman-Merkle modulus
1711  * \param dhm_G    Diffie-Hellman-Merkle generator
1712  *
1713  * \return         0 if successful
1714  */
1715 int mbedtls_ssl_conf_dh_param( mbedtls_ssl_config *conf, const char *dhm_P, const char *dhm_G );
1716 
1717 /**
1718  * \brief          Set the Diffie-Hellman public P and G values,
1719  *                 read from existing context (server-side only)
1720  *
1721  * \param conf     SSL configuration
1722  * \param dhm_ctx  Diffie-Hellman-Merkle context
1723  *
1724  * \return         0 if successful
1725  */
1726 int mbedtls_ssl_conf_dh_param_ctx( mbedtls_ssl_config *conf, mbedtls_dhm_context *dhm_ctx );
1727 #endif /* MBEDTLS_DHM_C && defined(MBEDTLS_SSL_SRV_C) */
1728 
1729 #if defined(MBEDTLS_DHM_C) && defined(MBEDTLS_SSL_CLI_C)
1730 /**
1731  * \brief          Set the minimum length for Diffie-Hellman parameters.
1732  *                 (Client-side only.)
1733  *                 (Default: 1024 bits.)
1734  *
1735  * \param conf     SSL configuration
1736  * \param bitlen   Minimum bit length of the DHM prime
1737  */
1738 void mbedtls_ssl_conf_dhm_min_bitlen( mbedtls_ssl_config *conf,
1739                                       unsigned int bitlen );
1740 #endif /* MBEDTLS_DHM_C && MBEDTLS_SSL_CLI_C */
1741 
1742 #if defined(MBEDTLS_ECP_C)
1743 /**
1744  * \brief          Set the allowed curves in order of preference.
1745  *                 (Default: all defined curves.)
1746  *
1747  *                 On server: this only affects selection of the ECDHE curve;
1748  *                 the curves used for ECDH and ECDSA are determined by the
1749  *                 list of available certificates instead.
1750  *
1751  *                 On client: this affects the list of curves offered for any
1752  *                 use. The server can override our preference order.
1753  *
1754  *                 Both sides: limits the set of curves accepted for use in
1755  *                 ECDHE and in the peer's end-entity certificate.
1756  *
1757  * \note           This has no influence on which curves are allowed inside the
1758  *                 certificate chains, see \c mbedtls_ssl_conf_cert_profile()
1759  *                 for that. For the end-entity certificate however, the key
1760  *                 will be accepted only if it is allowed both by this list
1761  *                 and by the cert profile.
1762  *
1763  * \note           This list should be ordered by decreasing preference
1764  *                 (preferred curve first).
1765  *
1766  * \param conf     SSL configuration
1767  * \param curves   Ordered list of allowed curves,
1768  *                 terminated by MBEDTLS_ECP_DP_NONE.
1769  */
1770 void mbedtls_ssl_conf_curves( mbedtls_ssl_config *conf,
1771                               const mbedtls_ecp_group_id *curves );
1772 #endif /* MBEDTLS_ECP_C */
1773 
1774 #if defined(MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED)
1775 /**
1776  * \brief          Set the allowed hashes for signatures during the handshake.
1777  *                 (Default: all available hashes except MD5.)
1778  *
1779  * \note           This only affects which hashes are offered and can be used
1780  *                 for signatures during the handshake. Hashes for message
1781  *                 authentication and the TLS PRF are controlled by the
1782  *                 ciphersuite, see \c mbedtls_ssl_conf_ciphersuites(). Hashes
1783  *                 used for certificate signature are controlled by the
1784  *                 verification profile, see \c mbedtls_ssl_conf_cert_profile().
1785  *
1786  * \note           This list should be ordered by decreasing preference
1787  *                 (preferred hash first).
1788  *
1789  * \param conf     SSL configuration
1790  * \param hashes   Ordered list of allowed signature hashes,
1791  *                 terminated by \c MBEDTLS_MD_NONE.
1792  */
1793 void mbedtls_ssl_conf_sig_hashes( mbedtls_ssl_config *conf,
1794                                   const int *hashes );
1795 #endif /* MBEDTLS_KEY_EXCHANGE__WITH_CERT__ENABLED */
1796 
1797 #if defined(MBEDTLS_X509_CRT_PARSE_C)
1798 /**
1799  * \brief          Set the hostname to check against the received server
1800  *                 certificate. It sets the ServerName TLS extension too,
1801  *                 if the extension is enabled.
1802  *                 (client-side only)
1803  *
1804  * \param ssl      SSL context
1805  * \param hostname the server hostname
1806  *
1807  * \return         0 if successful or MBEDTLS_ERR_SSL_ALLOC_FAILED
1808  */
1809 int mbedtls_ssl_set_hostname( mbedtls_ssl_context *ssl, const char *hostname );
1810 #endif /* MBEDTLS_X509_CRT_PARSE_C */
1811 
1812 #if defined(MBEDTLS_SSL_SERVER_NAME_INDICATION)
1813 /**
1814  * \brief          Set own certificate and key for the current handshake
1815  *
1816  * \note           Same as \c mbedtls_ssl_conf_own_cert() but for use within
1817  *                 the SNI callback.
1818  *
1819  * \param ssl      SSL context
1820  * \param own_cert own public certificate chain
1821  * \param pk_key   own private key
1822  *
1823  * \return         0 on success or MBEDTLS_ERR_SSL_ALLOC_FAILED
1824  */
1825 int mbedtls_ssl_set_hs_own_cert( mbedtls_ssl_context *ssl,
1826                                  mbedtls_x509_crt *own_cert,
1827                                  mbedtls_pk_context *pk_key );
1828 
1829 /**
1830  * \brief          Set the data required to verify peer certificate for the
1831  *                 current handshake
1832  *
1833  * \note           Same as \c mbedtls_ssl_conf_ca_chain() but for use within
1834  *                 the SNI callback.
1835  *
1836  * \param ssl      SSL context
1837  * \param ca_chain trusted CA chain (meaning all fully trusted top-level CAs)
1838  * \param ca_crl   trusted CA CRLs
1839  */
1840 void mbedtls_ssl_set_hs_ca_chain( mbedtls_ssl_context *ssl,
1841                                   mbedtls_x509_crt *ca_chain,
1842                                   mbedtls_x509_crl *ca_crl );
1843 
1844 /**
1845  * \brief          Set authmode for the current handshake.
1846  *
1847  * \note           Same as \c mbedtls_ssl_conf_authmode() but for use within
1848  *                 the SNI callback.
1849  *
1850  * \param ssl      SSL context
1851  * \param authmode MBEDTLS_SSL_VERIFY_NONE, MBEDTLS_SSL_VERIFY_OPTIONAL or
1852  *                 MBEDTLS_SSL_VERIFY_REQUIRED
1853  */
1854 void mbedtls_ssl_set_hs_authmode( mbedtls_ssl_context *ssl,
1855                                   int authmode );
1856 
1857 /**
1858  * \brief          Set server side ServerName TLS extension callback
1859  *                 (optional, server-side only).
1860  *
1861  *                 If set, the ServerName callback is called whenever the
1862  *                 server receives a ServerName TLS extension from the client
1863  *                 during a handshake. The ServerName callback has the
1864  *                 following parameters: (void *parameter, mbedtls_ssl_context *ssl,
1865  *                 const unsigned char *hostname, size_t len). If a suitable
1866  *                 certificate is found, the callback must set the
1867  *                 certificate(s) and key(s) to use with \c
1868  *                 mbedtls_ssl_set_hs_own_cert() (can be called repeatedly),
1869  *                 and may optionally adjust the CA and associated CRL with \c
1870  *                 mbedtls_ssl_set_hs_ca_chain() as well as the client
1871  *                 authentication mode with \c mbedtls_ssl_set_hs_authmode(),
1872  *                 then must return 0. If no matching name is found, the
1873  *                 callback must either set a default cert, or
1874  *                 return non-zero to abort the handshake at this point.
1875  *
1876  * \param conf     SSL configuration
1877  * \param f_sni    verification function
1878  * \param p_sni    verification parameter
1879  */
1880 void mbedtls_ssl_conf_sni( mbedtls_ssl_config *conf,
1881                   int (*f_sni)(void *, mbedtls_ssl_context *, const unsigned char *,
1882                                size_t),
1883                   void *p_sni );
1884 #endif /* MBEDTLS_SSL_SERVER_NAME_INDICATION */
1885 
1886 #if defined(MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED)
1887 /**
1888  * \brief          Set the EC J-PAKE password for current handshake.
1889  *
1890  * \note           An internal copy is made, and destroyed as soon as the
1891  *                 handshake is completed, or when the SSL context is reset or
1892  *                 freed.
1893  *
1894  * \note           The SSL context needs to be already set up. The right place
1895  *                 to call this function is between \c mbedtls_ssl_setup() or
1896  *                 \c mbedtls_ssl_reset() and \c mbedtls_ssl_handshake().
1897  *
1898  * \param ssl      SSL context
1899  * \param pw       EC J-PAKE password (pre-shared secret)
1900  * \param pw_len   length of pw in bytes
1901  *
1902  * \return         0 on success, or a negative error code.
1903  */
1904 int mbedtls_ssl_set_hs_ecjpake_password( mbedtls_ssl_context *ssl,
1905                                          const unsigned char *pw,
1906                                          size_t pw_len );
1907 #endif /*MBEDTLS_KEY_EXCHANGE_ECJPAKE_ENABLED */
1908 
1909 #if defined(MBEDTLS_SSL_ALPN)
1910 /**
1911  * \brief          Set the supported Application Layer Protocols.
1912  *
1913  * \param conf     SSL configuration
1914  * \param protos   Pointer to a NULL-terminated list of supported protocols,
1915  *                 in decreasing preference order. The pointer to the list is
1916  *                 recorded by the library for later reference as required, so
1917  *                 the lifetime of the table must be atleast as long as the
1918  *                 lifetime of the SSL configuration structure.
1919  *
1920  * \return         0 on success, or MBEDTLS_ERR_SSL_BAD_INPUT_DATA.
1921  */
1922 int mbedtls_ssl_conf_alpn_protocols( mbedtls_ssl_config *conf, const char **protos );
1923 
1924 /**
1925  * \brief          Get the name of the negotiated Application Layer Protocol.
1926  *                 This function should be called after the handshake is
1927  *                 completed.
1928  *
1929  * \param ssl      SSL context
1930  *
1931  * \return         Protcol name, or NULL if no protocol was negotiated.
1932  */
1933 const char *mbedtls_ssl_get_alpn_protocol( const mbedtls_ssl_context *ssl );
1934 #endif /* MBEDTLS_SSL_ALPN */
1935 
1936 /**
1937  * \brief          Set the maximum supported version sent from the client side
1938  *                 and/or accepted at the server side
1939  *                 (Default: MBEDTLS_SSL_MAX_MAJOR_VERSION, MBEDTLS_SSL_MAX_MINOR_VERSION)
1940  *
1941  * \note           This ignores ciphersuites from higher versions.
1942  *
1943  * \note           With DTLS, use MBEDTLS_SSL_MINOR_VERSION_2 for DTLS 1.0 and
1944  *                 MBEDTLS_SSL_MINOR_VERSION_3 for DTLS 1.2
1945  *
1946  * \param conf     SSL configuration
1947  * \param major    Major version number (only MBEDTLS_SSL_MAJOR_VERSION_3 supported)
1948  * \param minor    Minor version number (MBEDTLS_SSL_MINOR_VERSION_0,
1949  *                 MBEDTLS_SSL_MINOR_VERSION_1 and MBEDTLS_SSL_MINOR_VERSION_2,
1950  *                 MBEDTLS_SSL_MINOR_VERSION_3 supported)
1951  */
1952 void mbedtls_ssl_conf_max_version( mbedtls_ssl_config *conf, int major, int minor );
1953 
1954 /**
1955  * \brief          Set the minimum accepted SSL/TLS protocol version
1956  *                 (Default: TLS 1.0)
1957  *
1958  * \note           Input outside of the SSL_MAX_XXXXX_VERSION and
1959  *                 SSL_MIN_XXXXX_VERSION range is ignored.
1960  *
1961  * \note           MBEDTLS_SSL_MINOR_VERSION_0 (SSL v3) should be avoided.
1962  *
1963  * \note           With DTLS, use MBEDTLS_SSL_MINOR_VERSION_2 for DTLS 1.0 and
1964  *                 MBEDTLS_SSL_MINOR_VERSION_3 for DTLS 1.2
1965  *
1966  * \param conf     SSL configuration
1967  * \param major    Major version number (only MBEDTLS_SSL_MAJOR_VERSION_3 supported)
1968  * \param minor    Minor version number (MBEDTLS_SSL_MINOR_VERSION_0,
1969  *                 MBEDTLS_SSL_MINOR_VERSION_1 and MBEDTLS_SSL_MINOR_VERSION_2,
1970  *                 MBEDTLS_SSL_MINOR_VERSION_3 supported)
1971  */
1972 void mbedtls_ssl_conf_min_version( mbedtls_ssl_config *conf, int major, int minor );
1973 
1974 #if defined(MBEDTLS_SSL_FALLBACK_SCSV) && defined(MBEDTLS_SSL_CLI_C)
1975 /**
1976  * \brief          Set the fallback flag (client-side only).
1977  *                 (Default: MBEDTLS_SSL_IS_NOT_FALLBACK).
1978  *
1979  * \note           Set to MBEDTLS_SSL_IS_FALLBACK when preparing a fallback
1980  *                 connection, that is a connection with max_version set to a
1981  *                 lower value than the value you're willing to use. Such
1982  *                 fallback connections are not recommended but are sometimes
1983  *                 necessary to interoperate with buggy (version-intolerant)
1984  *                 servers.
1985  *
1986  * \warning        You should NOT set this to MBEDTLS_SSL_IS_FALLBACK for
1987  *                 non-fallback connections! This would appear to work for a
1988  *                 while, then cause failures when the server is upgraded to
1989  *                 support a newer TLS version.
1990  *
1991  * \param conf     SSL configuration
1992  * \param fallback MBEDTLS_SSL_IS_NOT_FALLBACK or MBEDTLS_SSL_IS_FALLBACK
1993  */
1994 void mbedtls_ssl_conf_fallback( mbedtls_ssl_config *conf, char fallback );
1995 #endif /* MBEDTLS_SSL_FALLBACK_SCSV && MBEDTLS_SSL_CLI_C */
1996 
1997 #if defined(MBEDTLS_SSL_ENCRYPT_THEN_MAC)
1998 /**
1999  * \brief           Enable or disable Encrypt-then-MAC
2000  *                  (Default: MBEDTLS_SSL_ETM_ENABLED)
2001  *
2002  * \note            This should always be enabled, it is a security
2003  *                  improvement, and should not cause any interoperability
2004  *                  issue (used only if the peer supports it too).
2005  *
2006  * \param conf      SSL configuration
2007  * \param etm       MBEDTLS_SSL_ETM_ENABLED or MBEDTLS_SSL_ETM_DISABLED
2008  */
2009 void mbedtls_ssl_conf_encrypt_then_mac( mbedtls_ssl_config *conf, char etm );
2010 #endif /* MBEDTLS_SSL_ENCRYPT_THEN_MAC */
2011 
2012 #if defined(MBEDTLS_SSL_EXTENDED_MASTER_SECRET)
2013 /**
2014  * \brief           Enable or disable Extended Master Secret negotiation.
2015  *                  (Default: MBEDTLS_SSL_EXTENDED_MS_ENABLED)
2016  *
2017  * \note            This should always be enabled, it is a security fix to the
2018  *                  protocol, and should not cause any interoperability issue
2019  *                  (used only if the peer supports it too).
2020  *
2021  * \param conf      SSL configuration
2022  * \param ems       MBEDTLS_SSL_EXTENDED_MS_ENABLED or MBEDTLS_SSL_EXTENDED_MS_DISABLED
2023  */
2024 void mbedtls_ssl_conf_extended_master_secret( mbedtls_ssl_config *conf, char ems );
2025 #endif /* MBEDTLS_SSL_EXTENDED_MASTER_SECRET */
2026 
2027 #if defined(MBEDTLS_ARC4_C)
2028 /**
2029  * \brief          Disable or enable support for RC4
2030  *                 (Default: MBEDTLS_SSL_ARC4_DISABLED)
2031  *
2032  * \warning        Use of RC4 in DTLS/TLS has been prohibited by RFC 7465
2033  *                 for security reasons. Use at your own risk.
2034  *
2035  * \note           This function is deprecated and will likely be removed in
2036  *                 a future version of the library.
2037  *                 RC4 is disabled by default at compile time and needs to be
2038  *                 actively enabled for use with legacy systems.
2039  *
2040  * \param conf     SSL configuration
2041  * \param arc4     MBEDTLS_SSL_ARC4_ENABLED or MBEDTLS_SSL_ARC4_DISABLED
2042  */
2043 void mbedtls_ssl_conf_arc4_support( mbedtls_ssl_config *conf, char arc4 );
2044 #endif /* MBEDTLS_ARC4_C */
2045 
2046 #if defined(MBEDTLS_SSL_SRV_C)
2047 /**
2048  * \brief          Whether to send a list of acceptable CAs in
2049  *                 CertificateRequest messages.
2050  *                 (Default: do send)
2051  *
2052  * \param conf     SSL configuration
2053  * \param cert_req_ca_list   MBEDTLS_SSL_CERT_REQ_CA_LIST_ENABLED or
2054  *                          MBEDTLS_SSL_CERT_REQ_CA_LIST_DISABLED
2055  */
2056 void mbedtls_ssl_conf_cert_req_ca_list( mbedtls_ssl_config *conf,
2057                                           char cert_req_ca_list );
2058 #endif /* MBEDTLS_SSL_SRV_C */
2059 
2060 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2061 /**
2062  * \brief          Set the maximum fragment length to emit and/or negotiate
2063  *                 (Default: MBEDTLS_SSL_MAX_CONTENT_LEN, usually 2^14 bytes)
2064  *                 (Server: set maximum fragment length to emit,
2065  *                 usually negotiated by the client during handshake
2066  *                 (Client: set maximum fragment length to emit *and*
2067  *                 negotiate with the server during handshake)
2068  *
2069  * \param conf     SSL configuration
2070  * \param mfl_code Code for maximum fragment length (allowed values:
2071  *                 MBEDTLS_SSL_MAX_FRAG_LEN_512,  MBEDTLS_SSL_MAX_FRAG_LEN_1024,
2072  *                 MBEDTLS_SSL_MAX_FRAG_LEN_2048, MBEDTLS_SSL_MAX_FRAG_LEN_4096)
2073  *
2074  * \return         0 if successful or MBEDTLS_ERR_SSL_BAD_INPUT_DATA
2075  */
2076 int mbedtls_ssl_conf_max_frag_len( mbedtls_ssl_config *conf, unsigned char mfl_code );
2077 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2078 
2079 #if defined(MBEDTLS_SSL_TRUNCATED_HMAC)
2080 /**
2081  * \brief          Activate negotiation of truncated HMAC
2082  *                 (Default: MBEDTLS_SSL_TRUNC_HMAC_DISABLED)
2083  *
2084  * \param conf     SSL configuration
2085  * \param truncate Enable or disable (MBEDTLS_SSL_TRUNC_HMAC_ENABLED or
2086  *                                    MBEDTLS_SSL_TRUNC_HMAC_DISABLED)
2087  */
2088 void mbedtls_ssl_conf_truncated_hmac( mbedtls_ssl_config *conf, int truncate );
2089 #endif /* MBEDTLS_SSL_TRUNCATED_HMAC */
2090 
2091 #if defined(MBEDTLS_SSL_CBC_RECORD_SPLITTING)
2092 /**
2093  * \brief          Enable / Disable 1/n-1 record splitting
2094  *                 (Default: MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED)
2095  *
2096  * \note           Only affects SSLv3 and TLS 1.0, not higher versions.
2097  *                 Does not affect non-CBC ciphersuites in any version.
2098  *
2099  * \param conf     SSL configuration
2100  * \param split    MBEDTLS_SSL_CBC_RECORD_SPLITTING_ENABLED or
2101  *                 MBEDTLS_SSL_CBC_RECORD_SPLITTING_DISABLED
2102  */
2103 void mbedtls_ssl_conf_cbc_record_splitting( mbedtls_ssl_config *conf, char split );
2104 #endif /* MBEDTLS_SSL_CBC_RECORD_SPLITTING */
2105 
2106 #if defined(MBEDTLS_SSL_SESSION_TICKETS) && defined(MBEDTLS_SSL_CLI_C)
2107 /**
2108  * \brief          Enable / Disable session tickets (client only).
2109  *                 (Default: MBEDTLS_SSL_SESSION_TICKETS_ENABLED.)
2110  *
2111  * \note           On server, use \c mbedtls_ssl_conf_session_tickets_cb().
2112  *
2113  * \param conf     SSL configuration
2114  * \param use_tickets   Enable or disable (MBEDTLS_SSL_SESSION_TICKETS_ENABLED or
2115  *                                         MBEDTLS_SSL_SESSION_TICKETS_DISABLED)
2116  */
2117 void mbedtls_ssl_conf_session_tickets( mbedtls_ssl_config *conf, int use_tickets );
2118 #endif /* MBEDTLS_SSL_SESSION_TICKETS && MBEDTLS_SSL_CLI_C */
2119 
2120 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2121 /**
2122  * \brief          Enable / Disable renegotiation support for connection when
2123  *                 initiated by peer
2124  *                 (Default: MBEDTLS_SSL_RENEGOTIATION_DISABLED)
2125  *
2126  * \warning        It is recommended to always disable renegotation unless you
2127  *                 know you need it and you know what you're doing. In the
2128  *                 past, there have been several issues associated with
2129  *                 renegotiation or a poor understanding of its properties.
2130  *
2131  * \note           Server-side, enabling renegotiation also makes the server
2132  *                 susceptible to a resource DoS by a malicious client.
2133  *
2134  * \param conf    SSL configuration
2135  * \param renegotiation     Enable or disable (MBEDTLS_SSL_RENEGOTIATION_ENABLED or
2136  *                                             MBEDTLS_SSL_RENEGOTIATION_DISABLED)
2137  */
2138 void mbedtls_ssl_conf_renegotiation( mbedtls_ssl_config *conf, int renegotiation );
2139 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2140 
2141 /**
2142  * \brief          Prevent or allow legacy renegotiation.
2143  *                 (Default: MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION)
2144  *
2145  *                 MBEDTLS_SSL_LEGACY_NO_RENEGOTIATION allows connections to
2146  *                 be established even if the peer does not support
2147  *                 secure renegotiation, but does not allow renegotiation
2148  *                 to take place if not secure.
2149  *                 (Interoperable and secure option)
2150  *
2151  *                 MBEDTLS_SSL_LEGACY_ALLOW_RENEGOTIATION allows renegotiations
2152  *                 with non-upgraded peers. Allowing legacy renegotiation
2153  *                 makes the connection vulnerable to specific man in the
2154  *                 middle attacks. (See RFC 5746)
2155  *                 (Most interoperable and least secure option)
2156  *
2157  *                 MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE breaks off connections
2158  *                 if peer does not support secure renegotiation. Results
2159  *                 in interoperability issues with non-upgraded peers
2160  *                 that do not support renegotiation altogether.
2161  *                 (Most secure option, interoperability issues)
2162  *
2163  * \param conf     SSL configuration
2164  * \param allow_legacy  Prevent or allow (SSL_NO_LEGACY_RENEGOTIATION,
2165  *                                        SSL_ALLOW_LEGACY_RENEGOTIATION or
2166  *                                        MBEDTLS_SSL_LEGACY_BREAK_HANDSHAKE)
2167  */
2168 void mbedtls_ssl_conf_legacy_renegotiation( mbedtls_ssl_config *conf, int allow_legacy );
2169 
2170 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2171 /**
2172  * \brief          Enforce renegotiation requests.
2173  *                 (Default: enforced, max_records = 16)
2174  *
2175  *                 When we request a renegotiation, the peer can comply or
2176  *                 ignore the request. This function allows us to decide
2177  *                 whether to enforce our renegotiation requests by closing
2178  *                 the connection if the peer doesn't comply.
2179  *
2180  *                 However, records could already be in transit from the peer
2181  *                 when the request is emitted. In order to increase
2182  *                 reliability, we can accept a number of records before the
2183  *                 expected handshake records.
2184  *
2185  *                 The optimal value is highly dependent on the specific usage
2186  *                 scenario.
2187  *
2188  * \note           With DTLS and server-initiated renegotiation, the
2189  *                 HelloRequest is retransmited every time mbedtls_ssl_read() times
2190  *                 out or receives Application Data, until:
2191  *                 - max_records records have beens seen, if it is >= 0, or
2192  *                 - the number of retransmits that would happen during an
2193  *                 actual handshake has been reached.
2194  *                 Please remember the request might be lost a few times
2195  *                 if you consider setting max_records to a really low value.
2196  *
2197  * \warning        On client, the grace period can only happen during
2198  *                 mbedtls_ssl_read(), as opposed to mbedtls_ssl_write() and mbedtls_ssl_renegotiate()
2199  *                 which always behave as if max_record was 0. The reason is,
2200  *                 if we receive application data from the server, we need a
2201  *                 place to write it, which only happens during mbedtls_ssl_read().
2202  *
2203  * \param conf     SSL configuration
2204  * \param max_records Use MBEDTLS_SSL_RENEGOTIATION_NOT_ENFORCED if you don't want to
2205  *                 enforce renegotiation, or a non-negative value to enforce
2206  *                 it but allow for a grace period of max_records records.
2207  */
2208 void mbedtls_ssl_conf_renegotiation_enforced( mbedtls_ssl_config *conf, int max_records );
2209 
2210 /**
2211  * \brief          Set record counter threshold for periodic renegotiation.
2212  *                 (Default: 2^48 - 1)
2213  *
2214  *                 Renegotiation is automatically triggered when a record
2215  *                 counter (outgoing or ingoing) crosses the defined
2216  *                 threshold. The default value is meant to prevent the
2217  *                 connection from being closed when the counter is about to
2218  *                 reached its maximal value (it is not allowed to wrap).
2219  *
2220  *                 Lower values can be used to enforce policies such as "keys
2221  *                 must be refreshed every N packets with cipher X".
2222  *
2223  *                 The renegotiation period can be disabled by setting
2224  *                 conf->disable_renegotiation to
2225  *                 MBEDTLS_SSL_RENEGOTIATION_DISABLED.
2226  *
2227  * \note           When the configured transport is
2228  *                 MBEDTLS_SSL_TRANSPORT_DATAGRAM the maximum renegotiation
2229  *                 period is 2^48 - 1, and for MBEDTLS_SSL_TRANSPORT_STREAM,
2230  *                 the maximum renegotiation period is 2^64 - 1.
2231  *
2232  * \param conf     SSL configuration
2233  * \param period   The threshold value: a big-endian 64-bit number.
2234  */
2235 void mbedtls_ssl_conf_renegotiation_period( mbedtls_ssl_config *conf,
2236                                    const unsigned char period[8] );
2237 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2238 
2239 /**
2240  * \brief          Return the number of data bytes available to read
2241  *
2242  * \param ssl      SSL context
2243  *
2244  * \return         how many bytes are available in the read buffer
2245  */
2246 size_t mbedtls_ssl_get_bytes_avail( const mbedtls_ssl_context *ssl );
2247 
2248 /**
2249  * \brief          Return the result of the certificate verification
2250  *
2251  * \param ssl      SSL context
2252  *
2253  * \return         0 if successful,
2254  *                 -1 if result is not available (eg because the handshake was
2255  *                 aborted too early), or
2256  *                 a combination of BADCERT_xxx and BADCRL_xxx flags, see
2257  *                 x509.h
2258  */
2259 uint32_t mbedtls_ssl_get_verify_result( const mbedtls_ssl_context *ssl );
2260 
2261 /**
2262  * \brief          Return the name of the current ciphersuite
2263  *
2264  * \param ssl      SSL context
2265  *
2266  * \return         a string containing the ciphersuite name
2267  */
2268 const char *mbedtls_ssl_get_ciphersuite( const mbedtls_ssl_context *ssl );
2269 
2270 /**
2271  * \brief          Return the current SSL version (SSLv3/TLSv1/etc)
2272  *
2273  * \param ssl      SSL context
2274  *
2275  * \return         a string containing the SSL version
2276  */
2277 const char *mbedtls_ssl_get_version( const mbedtls_ssl_context *ssl );
2278 
2279 /**
2280  * \brief          Return the (maximum) number of bytes added by the record
2281  *                 layer: header + encryption/MAC overhead (inc. padding)
2282  *
2283  * \param ssl      SSL context
2284  *
2285  * \return         Current maximum record expansion in bytes, or
2286  *                 MBEDTLS_ERR_SSL_FEATURE_UNAVAILABLE if compression is
2287  *                 enabled, which makes expansion much less predictable
2288  */
2289 int mbedtls_ssl_get_record_expansion( const mbedtls_ssl_context *ssl );
2290 
2291 #if defined(MBEDTLS_SSL_MAX_FRAGMENT_LENGTH)
2292 /**
2293  * \brief          Return the maximum fragment length (payload, in bytes).
2294  *                 This is the value negotiated with peer if any,
2295  *                 or the locally configured value.
2296  *
2297  * \note           With DTLS, \c mbedtls_ssl_write() will return an error if
2298  *                 called with a larger length value.
2299  *                 With TLS, \c mbedtls_ssl_write() will fragment the input if
2300  *                 necessary and return the number of bytes written; it is up
2301  *                 to the caller to call \c mbedtls_ssl_write() again in
2302  *                 order to send the remaining bytes if any.
2303  *
2304  * \param ssl      SSL context
2305  *
2306  * \return         Current maximum fragment length.
2307  */
2308 size_t mbedtls_ssl_get_max_frag_len( const mbedtls_ssl_context *ssl );
2309 #endif /* MBEDTLS_SSL_MAX_FRAGMENT_LENGTH */
2310 
2311 #if defined(MBEDTLS_X509_CRT_PARSE_C)
2312 /**
2313  * \brief          Return the peer certificate from the current connection
2314  *
2315  *                 Note: Can be NULL in case no certificate was sent during
2316  *                 the handshake. Different calls for the same connection can
2317  *                 return the same or different pointers for the same
2318  *                 certificate and even a different certificate altogether.
2319  *                 The peer cert CAN change in a single connection if
2320  *                 renegotiation is performed.
2321  *
2322  * \param ssl      SSL context
2323  *
2324  * \return         the current peer certificate
2325  */
2326 const mbedtls_x509_crt *mbedtls_ssl_get_peer_cert( const mbedtls_ssl_context *ssl );
2327 #endif /* MBEDTLS_X509_CRT_PARSE_C */
2328 
2329 #if defined(MBEDTLS_SSL_CLI_C)
2330 /**
2331  * \brief          Save session in order to resume it later (client-side only)
2332  *                 Session data is copied to presented session structure.
2333  *
2334  * \warning        Currently, peer certificate is lost in the operation.
2335  *
2336  * \param ssl      SSL context
2337  * \param session  session context
2338  *
2339  * \return         0 if successful,
2340  *                 MBEDTLS_ERR_SSL_ALLOC_FAILED if memory allocation failed,
2341  *                 MBEDTLS_ERR_SSL_BAD_INPUT_DATA if used server-side or
2342  *                 arguments are otherwise invalid
2343  *
2344  * \sa             mbedtls_ssl_set_session()
2345  */
2346 int mbedtls_ssl_get_session( const mbedtls_ssl_context *ssl, mbedtls_ssl_session *session );
2347 #endif /* MBEDTLS_SSL_CLI_C */
2348 
2349 /**
2350  * \brief          Perform the SSL handshake
2351  *
2352  * \param ssl      SSL context
2353  *
2354  * \return         0 if successful, or
2355  *                 MBEDTLS_ERR_SSL_WANT_READ or MBEDTLS_ERR_SSL_WANT_WRITE, or
2356  *                 MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED (see below), or
2357  *                 a specific SSL error code.
2358  *
2359  * \note           If this function returns something other than 0 or
2360  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
2361  *                 becomes unusable, and you should either free it or call
2362  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2363  *                 a new connection; the current connection must be closed.
2364  *
2365  * \note           If DTLS is in use, then you may choose to handle
2366  *                 MBEDTLS_ERR_SSL_HELLO_VERIFY_REQUIRED specially for logging
2367  *                 purposes, as it is an expected return value rather than an
2368  *                 actual error, but you still need to reset/free the context.
2369  */
2370 int mbedtls_ssl_handshake( mbedtls_ssl_context *ssl );
2371 
2372 /**
2373  * \brief          Perform a single step of the SSL handshake
2374  *
2375  * \note           The state of the context (ssl->state) will be at
2376  *                 the next state after execution of this function. Do not
2377  *                 call this function if state is MBEDTLS_SSL_HANDSHAKE_OVER.
2378  *
2379  * \note           If this function returns something other than 0 or
2380  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
2381  *                 becomes unusable, and you should either free it or call
2382  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2383  *                 a new connection; the current connection must be closed.
2384  *
2385  * \param ssl      SSL context
2386  *
2387  * \return         0 if successful, or
2388  *                 MBEDTLS_ERR_SSL_WANT_READ or MBEDTLS_ERR_SSL_WANT_WRITE, or
2389  *                 a specific SSL error code.
2390  */
2391 int mbedtls_ssl_handshake_step( mbedtls_ssl_context *ssl );
2392 
2393 #if defined(MBEDTLS_SSL_RENEGOTIATION)
2394 /**
2395  * \brief          Initiate an SSL renegotiation on the running connection.
2396  *                 Client: perform the renegotiation right now.
2397  *                 Server: request renegotiation, which will be performed
2398  *                 during the next call to mbedtls_ssl_read() if honored by
2399  *                 client.
2400  *
2401  * \param ssl      SSL context
2402  *
2403  * \return         0 if successful, or any mbedtls_ssl_handshake() return
2404  *                 value.
2405  *
2406  * \note           If this function returns something other than 0 or
2407  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
2408  *                 becomes unusable, and you should either free it or call
2409  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2410  *                 a new connection; the current connection must be closed.
2411  */
2412 int mbedtls_ssl_renegotiate( mbedtls_ssl_context *ssl );
2413 #endif /* MBEDTLS_SSL_RENEGOTIATION */
2414 
2415 /**
2416  * \brief          Read at most 'len' application data bytes
2417  *
2418  * \param ssl      SSL context
2419  * \param buf      buffer that will hold the data
2420  * \param len      maximum number of bytes to read
2421  *
2422  * \return         the number of bytes read, or
2423  *                 0 for EOF, or
2424  *                 MBEDTLS_ERR_SSL_WANT_READ or MBEDTLS_ERR_SSL_WANT_WRITE, or
2425  *                 MBEDTLS_ERR_SSL_CLIENT_RECONNECT (see below), or
2426  *                 another negative error code.
2427  *
2428  * \note           If this function returns something other than a positive
2429  *                 value or MBEDTLS_ERR_SSL_WANT_READ/WRITE or
2430  *                 MBEDTLS_ERR_SSL_CLIENT_RECONNECT, then the ssl context
2431  *                 becomes unusable, and you should either free it or call
2432  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2433  *                 a new connection; the current connection must be closed.
2434  *
2435  * \note           When this function return MBEDTLS_ERR_SSL_CLIENT_RECONNECT
2436  *                 (which can only happen server-side), it means that a client
2437  *                 is initiating a new connection using the same source port.
2438  *                 You can either treat that as a connection close and wait
2439  *                 for the client to resend a ClientHello, or directly
2440  *                 continue with \c mbedtls_ssl_handshake() with the same
2441  *                 context (as it has beeen reset internally). Either way, you
2442  *                 should make sure this is seen by the application as a new
2443  *                 connection: application state, if any, should be reset, and
2444  *                 most importantly the identity of the client must be checked
2445  *                 again. WARNING: not validating the identity of the client
2446  *                 again, or not transmitting the new identity to the
2447  *                 application layer, would allow authentication bypass!
2448  */
2449 int mbedtls_ssl_read( mbedtls_ssl_context *ssl, unsigned char *buf, size_t len );
2450 
2451 /**
2452  * \brief          Try to write exactly 'len' application data bytes
2453  *
2454  * \warning        This function will do partial writes in some cases. If the
2455  *                 return value is non-negative but less than length, the
2456  *                 function must be called again with updated arguments:
2457  *                 buf + ret, len - ret (if ret is the return value) until
2458  *                 it returns a value equal to the last 'len' argument.
2459  *
2460  * \param ssl      SSL context
2461  * \param buf      buffer holding the data
2462  * \param len      how many bytes must be written
2463  *
2464  * \return         the number of bytes actually written (may be less than len),
2465  *                 or MBEDTLS_ERR_SSL_WANT_WRITE or MBEDTLS_ERR_SSL_WANT_READ,
2466  *                 or another negative error code.
2467  *
2468  * \note           If this function returns something other than a positive
2469  *                 value or MBEDTLS_ERR_SSL_WANT_READ/WRITE, the ssl context
2470  *                 becomes unusable, and you should either free it or call
2471  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2472  *                 a new connection; the current connection must be closed.
2473  *
2474  * \note           When this function returns MBEDTLS_ERR_SSL_WANT_WRITE/READ,
2475  *                 it must be called later with the *same* arguments,
2476  *                 until it returns a positive value.
2477  *
2478  * \note           If the requested length is greater than the maximum
2479  *                 fragment length (either the built-in limit or the one set
2480  *                 or negotiated with the peer), then:
2481  *                 - with TLS, less bytes than requested are written.
2482  *                 - with DTLS, MBEDTLS_ERR_SSL_BAD_INPUT_DATA is returned.
2483  *                 \c mbedtls_ssl_get_max_frag_len() may be used to query the
2484  *                 active maximum fragment length.
2485  */
2486 int mbedtls_ssl_write( mbedtls_ssl_context *ssl, const unsigned char *buf, size_t len );
2487 
2488 /**
2489  * \brief           Send an alert message
2490  *
2491  * \param ssl       SSL context
2492  * \param level     The alert level of the message
2493  *                  (MBEDTLS_SSL_ALERT_LEVEL_WARNING or MBEDTLS_SSL_ALERT_LEVEL_FATAL)
2494  * \param message   The alert message (SSL_ALERT_MSG_*)
2495  *
2496  * \return          0 if successful, or a specific SSL error code.
2497  *
2498  * \note           If this function returns something other than 0 or
2499  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
2500  *                 becomes unusable, and you should either free it or call
2501  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2502  *                 a new connection; the current connection must be closed.
2503  */
2504 int mbedtls_ssl_send_alert_message( mbedtls_ssl_context *ssl,
2505                             unsigned char level,
2506                             unsigned char message );
2507 /**
2508  * \brief          Notify the peer that the connection is being closed
2509  *
2510  * \param ssl      SSL context
2511  *
2512  * \return          0 if successful, or a specific SSL error code.
2513  *
2514  * \note           If this function returns something other than 0 or
2515  *                 MBEDTLS_ERR_SSL_WANT_READ/WRITE, then the ssl context
2516  *                 becomes unusable, and you should either free it or call
2517  *                 \c mbedtls_ssl_session_reset() on it before re-using it for
2518  *                 a new connection; the current connection must be closed.
2519  */
2520 int mbedtls_ssl_close_notify( mbedtls_ssl_context *ssl );
2521 
2522 /**
2523  * \brief          Free referenced items in an SSL context and clear memory
2524  *
2525  * \param ssl      SSL context
2526  */
2527 void mbedtls_ssl_free( mbedtls_ssl_context *ssl );
2528 
2529 /**
2530  * \brief          Initialize an SSL configuration context
2531  *                 Just makes the context ready for
2532  *                 mbedtls_ssl_config_defaults() or mbedtls_ssl_config_free().
2533  *
2534  * \note           You need to call mbedtls_ssl_config_defaults() unless you
2535  *                 manually set all of the relevent fields yourself.
2536  *
2537  * \param conf     SSL configuration context
2538  */
2539 void mbedtls_ssl_config_init( mbedtls_ssl_config *conf );
2540 
2541 /**
2542  * \brief          Load reasonnable default SSL configuration values.
2543  *                 (You need to call mbedtls_ssl_config_init() first.)
2544  *
2545  * \param conf     SSL configuration context
2546  * \param endpoint MBEDTLS_SSL_IS_CLIENT or MBEDTLS_SSL_IS_SERVER
2547  * \param transport MBEDTLS_SSL_TRANSPORT_STREAM for TLS, or
2548  *                  MBEDTLS_SSL_TRANSPORT_DATAGRAM for DTLS
2549  * \param preset   a MBEDTLS_SSL_PRESET_XXX value
2550  *
2551  * \note           See \c mbedtls_ssl_conf_transport() for notes on DTLS.
2552  *
2553  * \return         0 if successful, or
2554  *                 MBEDTLS_ERR_XXX_ALLOC_FAILED on memory allocation error.
2555  */
2556 int mbedtls_ssl_config_defaults( mbedtls_ssl_config *conf,
2557                                  int endpoint, int transport, int preset );
2558 
2559 /**
2560  * \brief          Free an SSL configuration context
2561  *
2562  * \param conf     SSL configuration context
2563  */
2564 void mbedtls_ssl_config_free( mbedtls_ssl_config *conf );
2565 
2566 /**
2567  * \brief          Initialize SSL session structure
2568  *
2569  * \param session  SSL session
2570  */
2571 void mbedtls_ssl_session_init( mbedtls_ssl_session *session );
2572 
2573 /**
2574  * \brief          Free referenced items in an SSL session including the
2575  *                 peer certificate and clear memory
2576  *
2577  * \param session  SSL session
2578  */
2579 void mbedtls_ssl_session_free( mbedtls_ssl_session *session );
2580 
2581 #ifdef __cplusplus
2582 }
2583 #endif
2584 
2585 #endif /* ssl.h */
2586