1 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
2  * All rights reserved.
3  *
4  * This package is an SSL implementation written
5  * by Eric Young (eay@cryptsoft.com).
6  * The implementation was written so as to conform with Netscapes SSL.
7  *
8  * This library is free for commercial and non-commercial use as long as
9  * the following conditions are aheared to.  The following conditions
10  * apply to all code found in this distribution, be it the RC4, RSA,
11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
12  * included with this distribution is covered by the same copyright terms
13  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
14  *
15  * Copyright remains Eric Young's, and as such any Copyright notices in
16  * the code are not to be removed.
17  * If this package is used in a product, Eric Young should be given attribution
18  * as the author of the parts of the library used.
19  * This can be in the form of a textual message at program startup or
20  * in documentation (online or textual) provided with the package.
21  *
22  * Redistribution and use in source and binary forms, with or without
23  * modification, are permitted provided that the following conditions
24  * are met:
25  * 1. Redistributions of source code must retain the copyright
26  *    notice, this list of conditions and the following disclaimer.
27  * 2. Redistributions in binary form must reproduce the above copyright
28  *    notice, this list of conditions and the following disclaimer in the
29  *    documentation and/or other materials provided with the distribution.
30  * 3. All advertising materials mentioning features or use of this software
31  *    must display the following acknowledgement:
32  *    "This product includes cryptographic software written by
33  *     Eric Young (eay@cryptsoft.com)"
34  *    The word 'cryptographic' can be left out if the rouines from the library
35  *    being used are not cryptographic related :-).
36  * 4. If you include any Windows specific code (or a derivative thereof) from
37  *    the apps directory (application code) you must include an acknowledgement:
38  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
39  *
40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
50  * SUCH DAMAGE.
51  *
52  * The licence and distribution terms for any publically available version or
53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
54  * copied and put under another distribution licence
55  * [including the GNU Public Licence.]
56  */
57 /* ====================================================================
58  * Copyright (c) 1998-2007 The OpenSSL Project.  All rights reserved.
59  *
60  * Redistribution and use in source and binary forms, with or without
61  * modification, are permitted provided that the following conditions
62  * are met:
63  *
64  * 1. Redistributions of source code must retain the above copyright
65  *    notice, this list of conditions and the following disclaimer.
66  *
67  * 2. Redistributions in binary form must reproduce the above copyright
68  *    notice, this list of conditions and the following disclaimer in
69  *    the documentation and/or other materials provided with the
70  *    distribution.
71  *
72  * 3. All advertising materials mentioning features or use of this
73  *    software must display the following acknowledgment:
74  *    "This product includes software developed by the OpenSSL Project
75  *    for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
76  *
77  * 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
78  *    endorse or promote products derived from this software without
79  *    prior written permission. For written permission, please contact
80  *    openssl-core@openssl.org.
81  *
82  * 5. Products derived from this software may not be called "OpenSSL"
83  *    nor may "OpenSSL" appear in their names without prior written
84  *    permission of the OpenSSL Project.
85  *
86  * 6. Redistributions of any form whatsoever must retain the following
87  *    acknowledgment:
88  *    "This product includes software developed by the OpenSSL Project
89  *    for use in the OpenSSL Toolkit (http://www.openssl.org/)"
90  *
91  * THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
92  * EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
93  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
94  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE OpenSSL PROJECT OR
95  * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
96  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
97  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
98  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
99  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
100  * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
101  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
102  * OF THE POSSIBILITY OF SUCH DAMAGE.
103  * ====================================================================
104  *
105  * This product includes cryptographic software written by Eric Young
106  * (eay@cryptsoft.com).  This product includes software written by Tim
107  * Hudson (tjh@cryptsoft.com).
108  *
109  */
110 /* ====================================================================
111  * Copyright 2002 Sun Microsystems, Inc. ALL RIGHTS RESERVED.
112  * ECC cipher suite support in OpenSSL originally developed by
113  * SUN MICROSYSTEMS, INC., and contributed to the OpenSSL project.
114  */
115 /* ====================================================================
116  * Copyright 2005 Nokia. All rights reserved.
117  *
118  * The portions of the attached software ("Contribution") is developed by
119  * Nokia Corporation and is licensed pursuant to the OpenSSL open source
120  * license.
121  *
122  * The Contribution, originally written by Mika Kousa and Pasi Eronen of
123  * Nokia Corporation, consists of the "PSK" (Pre-Shared Key) ciphersuites
124  * support (see RFC 4279) to OpenSSL.
125  *
126  * No patent licenses or other rights except those expressly stated in
127  * the OpenSSL open source license shall be deemed granted or received
128  * expressly, by implication, estoppel, or otherwise.
129  *
130  * No assurances are provided by Nokia that the Contribution does not
131  * infringe the patent or other intellectual property rights of any third
132  * party or that the license provides you with all the necessary rights
133  * to make use of the Contribution.
134  *
135  * THE SOFTWARE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. IN
136  * ADDITION TO THE DISCLAIMERS INCLUDED IN THE LICENSE, NOKIA
137  * SPECIFICALLY DISCLAIMS ANY LIABILITY FOR CLAIMS BROUGHT BY YOU OR ANY
138  * OTHER ENTITY BASED ON INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS OR
139  * OTHERWISE.
140  */
141 
142 #ifndef OPENSSL_HEADER_SSL_H
143 #define OPENSSL_HEADER_SSL_H
144 
145 #include <openssl/base.h>
146 
147 #include <openssl/bio.h>
148 #include <openssl/buf.h>
149 #include <openssl/pem.h>
150 #include <openssl/span.h>
151 #include <openssl/ssl3.h>
152 #include <openssl/thread.h>
153 #include <openssl/tls1.h>
154 #include <openssl/x509.h>
155 
156 #if !defined(OPENSSL_WINDOWS)
157 #include <sys/time.h>
158 #endif
159 
160 // NGINX needs this #include. Consider revisiting this after NGINX 1.14.0 has
161 // been out for a year or so (assuming that they fix it in that release.) See
162 // https://boringssl-review.googlesource.com/c/boringssl/+/21664.
163 #include <openssl/hmac.h>
164 
165 // Forward-declare struct timeval. On Windows, it is defined in winsock2.h and
166 // Windows headers define too many macros to be included in public headers.
167 // However, only a forward declaration is needed.
168 struct timeval;
169 
170 #if defined(__cplusplus)
171 extern "C" {
172 #endif
173 
174 
175 // SSL implementation.
176 
177 
178 // SSL contexts.
179 //
180 // |SSL_CTX| objects manage shared state and configuration between multiple TLS
181 // or DTLS connections. Whether the connections are TLS or DTLS is selected by
182 // an |SSL_METHOD| on creation.
183 //
184 // |SSL_CTX| are reference-counted and may be shared by connections across
185 // multiple threads. Once shared, functions which change the |SSL_CTX|'s
186 // configuration may not be used.
187 
188 // TLS_method is the |SSL_METHOD| used for TLS connections.
189 OPENSSL_EXPORT const SSL_METHOD *TLS_method(void);
190 
191 // DTLS_method is the |SSL_METHOD| used for DTLS connections.
192 OPENSSL_EXPORT const SSL_METHOD *DTLS_method(void);
193 
194 // TLS_with_buffers_method is like |TLS_method|, but avoids all use of
195 // crypto/x509. All client connections created with |TLS_with_buffers_method|
196 // will fail unless a certificate verifier is installed with
197 // |SSL_set_custom_verify| or |SSL_CTX_set_custom_verify|.
198 OPENSSL_EXPORT const SSL_METHOD *TLS_with_buffers_method(void);
199 
200 // DTLS_with_buffers_method is like |DTLS_method|, but avoids all use of
201 // crypto/x509.
202 OPENSSL_EXPORT const SSL_METHOD *DTLS_with_buffers_method(void);
203 
204 // SSL_CTX_new returns a newly-allocated |SSL_CTX| with default settings or NULL
205 // on error.
206 OPENSSL_EXPORT SSL_CTX *SSL_CTX_new(const SSL_METHOD *method);
207 
208 // SSL_CTX_up_ref increments the reference count of |ctx|. It returns one.
209 OPENSSL_EXPORT int SSL_CTX_up_ref(SSL_CTX *ctx);
210 
211 // SSL_CTX_free releases memory associated with |ctx|.
212 OPENSSL_EXPORT void SSL_CTX_free(SSL_CTX *ctx);
213 
214 
215 // SSL connections.
216 //
217 // An |SSL| object represents a single TLS or DTLS connection. Although the
218 // shared |SSL_CTX| is thread-safe, an |SSL| is not thread-safe and may only be
219 // used on one thread at a time.
220 
221 // SSL_new returns a newly-allocated |SSL| using |ctx| or NULL on error. The new
222 // connection inherits settings from |ctx| at the time of creation. Settings may
223 // also be individually configured on the connection.
224 //
225 // On creation, an |SSL| is not configured to be either a client or server. Call
226 // |SSL_set_connect_state| or |SSL_set_accept_state| to set this.
227 OPENSSL_EXPORT SSL *SSL_new(SSL_CTX *ctx);
228 
229 // SSL_free releases memory associated with |ssl|.
230 OPENSSL_EXPORT void SSL_free(SSL *ssl);
231 
232 // SSL_get_SSL_CTX returns the |SSL_CTX| associated with |ssl|. If
233 // |SSL_set_SSL_CTX| is called, it returns the new |SSL_CTX|, not the initial
234 // one.
235 OPENSSL_EXPORT SSL_CTX *SSL_get_SSL_CTX(const SSL *ssl);
236 
237 // SSL_set_connect_state configures |ssl| to be a client.
238 OPENSSL_EXPORT void SSL_set_connect_state(SSL *ssl);
239 
240 // SSL_set_accept_state configures |ssl| to be a server.
241 OPENSSL_EXPORT void SSL_set_accept_state(SSL *ssl);
242 
243 // SSL_is_server returns one if |ssl| is configured as a server and zero
244 // otherwise.
245 OPENSSL_EXPORT int SSL_is_server(const SSL *ssl);
246 
247 // SSL_is_dtls returns one if |ssl| is a DTLS connection and zero otherwise.
248 OPENSSL_EXPORT int SSL_is_dtls(const SSL *ssl);
249 
250 // SSL_set_bio configures |ssl| to read from |rbio| and write to |wbio|. |ssl|
251 // takes ownership of the two |BIO|s. If |rbio| and |wbio| are the same, |ssl|
252 // only takes ownership of one reference.
253 //
254 // In DTLS, |rbio| must be non-blocking to properly handle timeouts and
255 // retransmits.
256 //
257 // If |rbio| is the same as the currently configured |BIO| for reading, that
258 // side is left untouched and is not freed.
259 //
260 // If |wbio| is the same as the currently configured |BIO| for writing AND |ssl|
261 // is not currently configured to read from and write to the same |BIO|, that
262 // side is left untouched and is not freed. This asymmetry is present for
263 // historical reasons.
264 //
265 // Due to the very complex historical behavior of this function, calling this
266 // function if |ssl| already has |BIO|s configured is deprecated. Prefer
267 // |SSL_set0_rbio| and |SSL_set0_wbio| instead.
268 OPENSSL_EXPORT void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio);
269 
270 // SSL_set0_rbio configures |ssl| to read from |rbio|. It takes ownership of
271 // |rbio|.
272 //
273 // Note that, although this function and |SSL_set0_wbio| may be called on the
274 // same |BIO|, each call takes a reference. Use |BIO_up_ref| to balance this.
275 OPENSSL_EXPORT void SSL_set0_rbio(SSL *ssl, BIO *rbio);
276 
277 // SSL_set0_wbio configures |ssl| to write to |wbio|. It takes ownership of
278 // |wbio|.
279 //
280 // Note that, although this function and |SSL_set0_rbio| may be called on the
281 // same |BIO|, each call takes a reference. Use |BIO_up_ref| to balance this.
282 OPENSSL_EXPORT void SSL_set0_wbio(SSL *ssl, BIO *wbio);
283 
284 // SSL_get_rbio returns the |BIO| that |ssl| reads from.
285 OPENSSL_EXPORT BIO *SSL_get_rbio(const SSL *ssl);
286 
287 // SSL_get_wbio returns the |BIO| that |ssl| writes to.
288 OPENSSL_EXPORT BIO *SSL_get_wbio(const SSL *ssl);
289 
290 // SSL_get_fd calls |SSL_get_rfd|.
291 OPENSSL_EXPORT int SSL_get_fd(const SSL *ssl);
292 
293 // SSL_get_rfd returns the file descriptor that |ssl| is configured to read
294 // from. If |ssl|'s read |BIO| is not configured or doesn't wrap a file
295 // descriptor then it returns -1.
296 //
297 // Note: On Windows, this may return either a file descriptor or a socket (cast
298 // to int), depending on whether |ssl| was configured with a file descriptor or
299 // socket |BIO|.
300 OPENSSL_EXPORT int SSL_get_rfd(const SSL *ssl);
301 
302 // SSL_get_wfd returns the file descriptor that |ssl| is configured to write
303 // to. If |ssl|'s write |BIO| is not configured or doesn't wrap a file
304 // descriptor then it returns -1.
305 //
306 // Note: On Windows, this may return either a file descriptor or a socket (cast
307 // to int), depending on whether |ssl| was configured with a file descriptor or
308 // socket |BIO|.
309 OPENSSL_EXPORT int SSL_get_wfd(const SSL *ssl);
310 
311 // SSL_set_fd configures |ssl| to read from and write to |fd|. It returns one
312 // on success and zero on allocation error. The caller retains ownership of
313 // |fd|.
314 //
315 // On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
316 OPENSSL_EXPORT int SSL_set_fd(SSL *ssl, int fd);
317 
318 // SSL_set_rfd configures |ssl| to read from |fd|. It returns one on success and
319 // zero on allocation error. The caller retains ownership of |fd|.
320 //
321 // On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
322 OPENSSL_EXPORT int SSL_set_rfd(SSL *ssl, int fd);
323 
324 // SSL_set_wfd configures |ssl| to write to |fd|. It returns one on success and
325 // zero on allocation error. The caller retains ownership of |fd|.
326 //
327 // On Windows, |fd| is cast to a |SOCKET| and used with Winsock APIs.
328 OPENSSL_EXPORT int SSL_set_wfd(SSL *ssl, int fd);
329 
330 // SSL_do_handshake continues the current handshake. If there is none or the
331 // handshake has completed or False Started, it returns one. Otherwise, it
332 // returns <= 0. The caller should pass the value into |SSL_get_error| to
333 // determine how to proceed.
334 //
335 // In DTLS, the caller must drive retransmissions. Whenever |SSL_get_error|
336 // signals |SSL_ERROR_WANT_READ|, use |DTLSv1_get_timeout| to determine the
337 // current timeout. If it expires before the next retry, call
338 // |DTLSv1_handle_timeout|. Note that DTLS handshake retransmissions use fresh
339 // sequence numbers, so it is not sufficient to replay packets at the transport.
340 //
341 // TODO(davidben): Ensure 0 is only returned on transport EOF.
342 // https://crbug.com/466303.
343 OPENSSL_EXPORT int SSL_do_handshake(SSL *ssl);
344 
345 // SSL_connect configures |ssl| as a client, if unconfigured, and calls
346 // |SSL_do_handshake|.
347 OPENSSL_EXPORT int SSL_connect(SSL *ssl);
348 
349 // SSL_accept configures |ssl| as a server, if unconfigured, and calls
350 // |SSL_do_handshake|.
351 OPENSSL_EXPORT int SSL_accept(SSL *ssl);
352 
353 // SSL_read reads up to |num| bytes from |ssl| into |buf|. It implicitly runs
354 // any pending handshakes, including renegotiations when enabled. On success, it
355 // returns the number of bytes read. Otherwise, it returns <= 0. The caller
356 // should pass the value into |SSL_get_error| to determine how to proceed.
357 //
358 // TODO(davidben): Ensure 0 is only returned on transport EOF.
359 // https://crbug.com/466303.
360 OPENSSL_EXPORT int SSL_read(SSL *ssl, void *buf, int num);
361 
362 // SSL_peek behaves like |SSL_read| but does not consume any bytes returned.
363 OPENSSL_EXPORT int SSL_peek(SSL *ssl, void *buf, int num);
364 
365 // SSL_pending returns the number of bytes available in |ssl|. It does not read
366 // from the transport.
367 OPENSSL_EXPORT int SSL_pending(const SSL *ssl);
368 
369 // SSL_write writes up to |num| bytes from |buf| into |ssl|. It implicitly runs
370 // any pending handshakes, including renegotiations when enabled. On success, it
371 // returns the number of bytes written. Otherwise, it returns <= 0. The caller
372 // should pass the value into |SSL_get_error| to determine how to proceed.
373 //
374 // In TLS, a non-blocking |SSL_write| differs from non-blocking |write| in that
375 // a failed |SSL_write| still commits to the data passed in. When retrying, the
376 // caller must supply the original write buffer (or a larger one containing the
377 // original as a prefix). By default, retries will fail if they also do not
378 // reuse the same |buf| pointer. This may be relaxed with
379 // |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER|, but the buffer contents still must be
380 // unchanged.
381 //
382 // By default, in TLS, |SSL_write| will not return success until all |num| bytes
383 // are written. This may be relaxed with |SSL_MODE_ENABLE_PARTIAL_WRITE|. It
384 // allows |SSL_write| to complete with a partial result when only part of the
385 // input was written in a single record.
386 //
387 // In DTLS, neither |SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER| and
388 // |SSL_MODE_ENABLE_PARTIAL_WRITE| do anything. The caller may retry with a
389 // different buffer freely. A single call to |SSL_write| only ever writes a
390 // single record in a single packet, so |num| must be at most
391 // |SSL3_RT_MAX_PLAIN_LENGTH|.
392 //
393 // TODO(davidben): Ensure 0 is only returned on transport EOF.
394 // https://crbug.com/466303.
395 OPENSSL_EXPORT int SSL_write(SSL *ssl, const void *buf, int num);
396 
397 // SSL_KEY_UPDATE_REQUESTED indicates that the peer should reply to a KeyUpdate
398 // message with its own, thus updating traffic secrets for both directions on
399 // the connection.
400 #define SSL_KEY_UPDATE_REQUESTED 1
401 
402 // SSL_KEY_UPDATE_NOT_REQUESTED indicates that the peer should not reply with
403 // it's own KeyUpdate message.
404 #define SSL_KEY_UPDATE_NOT_REQUESTED 0
405 
406 // SSL_key_update queues a TLS 1.3 KeyUpdate message to be sent on |ssl|
407 // if one is not already queued. The |request_type| argument must one of the
408 // |SSL_KEY_UPDATE_*| values. This function requires that |ssl| have completed a
409 // TLS >= 1.3 handshake. It returns one on success or zero on error.
410 //
411 // Note that this function does not _send_ the message itself. The next call to
412 // |SSL_write| will cause the message to be sent. |SSL_write| may be called with
413 // a zero length to flush a KeyUpdate message when no application data is
414 // pending.
415 OPENSSL_EXPORT int SSL_key_update(SSL *ssl, int request_type);
416 
417 // SSL_shutdown shuts down |ssl|. It runs in two stages. First, it sends
418 // close_notify and returns zero or one on success or -1 on failure. Zero
419 // indicates that close_notify was sent, but not received, and one additionally
420 // indicates that the peer's close_notify had already been received.
421 //
422 // To then wait for the peer's close_notify, run |SSL_shutdown| to completion a
423 // second time. This returns 1 on success and -1 on failure. Application data
424 // is considered a fatal error at this point. To process or discard it, read
425 // until close_notify with |SSL_read| instead.
426 //
427 // In both cases, on failure, pass the return value into |SSL_get_error| to
428 // determine how to proceed.
429 //
430 // Most callers should stop at the first stage. Reading for close_notify is
431 // primarily used for uncommon protocols where the underlying transport is
432 // reused after TLS completes. Additionally, DTLS uses an unordered transport
433 // and is unordered, so the second stage is a no-op in DTLS.
434 OPENSSL_EXPORT int SSL_shutdown(SSL *ssl);
435 
436 // SSL_CTX_set_quiet_shutdown sets quiet shutdown on |ctx| to |mode|. If
437 // enabled, |SSL_shutdown| will not send a close_notify alert or wait for one
438 // from the peer. It will instead synchronously return one.
439 OPENSSL_EXPORT void SSL_CTX_set_quiet_shutdown(SSL_CTX *ctx, int mode);
440 
441 // SSL_CTX_get_quiet_shutdown returns whether quiet shutdown is enabled for
442 // |ctx|.
443 OPENSSL_EXPORT int SSL_CTX_get_quiet_shutdown(const SSL_CTX *ctx);
444 
445 // SSL_set_quiet_shutdown sets quiet shutdown on |ssl| to |mode|. If enabled,
446 // |SSL_shutdown| will not send a close_notify alert or wait for one from the
447 // peer. It will instead synchronously return one.
448 OPENSSL_EXPORT void SSL_set_quiet_shutdown(SSL *ssl, int mode);
449 
450 // SSL_get_quiet_shutdown returns whether quiet shutdown is enabled for
451 // |ssl|.
452 OPENSSL_EXPORT int SSL_get_quiet_shutdown(const SSL *ssl);
453 
454 // SSL_get_error returns a |SSL_ERROR_*| value for the most recent operation on
455 // |ssl|. It should be called after an operation failed to determine whether the
456 // error was fatal and, if not, when to retry.
457 OPENSSL_EXPORT int SSL_get_error(const SSL *ssl, int ret_code);
458 
459 // SSL_ERROR_NONE indicates the operation succeeded.
460 #define SSL_ERROR_NONE 0
461 
462 // SSL_ERROR_SSL indicates the operation failed within the library. The caller
463 // may inspect the error queue for more information.
464 #define SSL_ERROR_SSL 1
465 
466 // SSL_ERROR_WANT_READ indicates the operation failed attempting to read from
467 // the transport. The caller may retry the operation when the transport is ready
468 // for reading.
469 //
470 // If signaled by a DTLS handshake, the caller must also call
471 // |DTLSv1_get_timeout| and |DTLSv1_handle_timeout| as appropriate. See
472 // |SSL_do_handshake|.
473 #define SSL_ERROR_WANT_READ 2
474 
475 // SSL_ERROR_WANT_WRITE indicates the operation failed attempting to write to
476 // the transport. The caller may retry the operation when the transport is ready
477 // for writing.
478 #define SSL_ERROR_WANT_WRITE 3
479 
480 // SSL_ERROR_WANT_X509_LOOKUP indicates the operation failed in calling the
481 // |cert_cb| or |client_cert_cb|. The caller may retry the operation when the
482 // callback is ready to return a certificate or one has been configured
483 // externally.
484 //
485 // See also |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb|.
486 #define SSL_ERROR_WANT_X509_LOOKUP 4
487 
488 // SSL_ERROR_SYSCALL indicates the operation failed externally to the library.
489 // The caller should consult the system-specific error mechanism. This is
490 // typically |errno| but may be something custom if using a custom |BIO|. It
491 // may also be signaled if the transport returned EOF, in which case the
492 // operation's return value will be zero.
493 #define SSL_ERROR_SYSCALL 5
494 
495 // SSL_ERROR_ZERO_RETURN indicates the operation failed because the connection
496 // was cleanly shut down with a close_notify alert.
497 #define SSL_ERROR_ZERO_RETURN 6
498 
499 // SSL_ERROR_WANT_CONNECT indicates the operation failed attempting to connect
500 // the transport (the |BIO| signaled |BIO_RR_CONNECT|). The caller may retry the
501 // operation when the transport is ready.
502 #define SSL_ERROR_WANT_CONNECT 7
503 
504 // SSL_ERROR_WANT_ACCEPT indicates the operation failed attempting to accept a
505 // connection from the transport (the |BIO| signaled |BIO_RR_ACCEPT|). The
506 // caller may retry the operation when the transport is ready.
507 //
508 // TODO(davidben): Remove this. It's used by accept BIOs which are bizarre.
509 #define SSL_ERROR_WANT_ACCEPT 8
510 
511 // SSL_ERROR_WANT_CHANNEL_ID_LOOKUP indicates the operation failed looking up
512 // the Channel ID key. The caller may retry the operation when |channel_id_cb|
513 // is ready to return a key or one has been configured with
514 // |SSL_set1_tls_channel_id|.
515 //
516 // See also |SSL_CTX_set_channel_id_cb|.
517 #define SSL_ERROR_WANT_CHANNEL_ID_LOOKUP 9
518 
519 // SSL_ERROR_PENDING_SESSION indicates the operation failed because the session
520 // lookup callback indicated the session was unavailable. The caller may retry
521 // the operation when lookup has completed.
522 //
523 // See also |SSL_CTX_sess_set_get_cb| and |SSL_magic_pending_session_ptr|.
524 #define SSL_ERROR_PENDING_SESSION 11
525 
526 // SSL_ERROR_PENDING_CERTIFICATE indicates the operation failed because the
527 // early callback indicated certificate lookup was incomplete. The caller may
528 // retry the operation when lookup has completed.
529 //
530 // See also |SSL_CTX_set_select_certificate_cb|.
531 #define SSL_ERROR_PENDING_CERTIFICATE 12
532 
533 // SSL_ERROR_WANT_PRIVATE_KEY_OPERATION indicates the operation failed because
534 // a private key operation was unfinished. The caller may retry the operation
535 // when the private key operation is complete.
536 //
537 // See also |SSL_set_private_key_method| and
538 // |SSL_CTX_set_private_key_method|.
539 #define SSL_ERROR_WANT_PRIVATE_KEY_OPERATION 13
540 
541 // SSL_ERROR_PENDING_TICKET indicates that a ticket decryption is pending. The
542 // caller may retry the operation when the decryption is ready.
543 //
544 // See also |SSL_CTX_set_ticket_aead_method|.
545 #define SSL_ERROR_PENDING_TICKET 14
546 
547 // SSL_ERROR_EARLY_DATA_REJECTED indicates that early data was rejected. The
548 // caller should treat this as a connection failure and retry any operations
549 // associated with the rejected early data. |SSL_reset_early_data_reject| may be
550 // used to reuse the underlying connection for the retry.
551 #define SSL_ERROR_EARLY_DATA_REJECTED 15
552 
553 // SSL_ERROR_WANT_CERTIFICATE_VERIFY indicates the operation failed because
554 // certificate verification was incomplete. The caller may retry the operation
555 // when certificate verification is complete.
556 //
557 // See also |SSL_CTX_set_custom_verify|.
558 #define SSL_ERROR_WANT_CERTIFICATE_VERIFY 16
559 
560 #define SSL_ERROR_HANDOFF 17
561 #define SSL_ERROR_HANDBACK 18
562 
563 // SSL_ERROR_WANT_RENEGOTIATE indicates the operation is pending a response to
564 // a renegotiation request from the server. The caller may call
565 // |SSL_renegotiate| to schedule a renegotiation and retry the operation.
566 //
567 // See also |ssl_renegotiate_explicit|.
568 #define SSL_ERROR_WANT_RENEGOTIATE 19
569 
570 // SSL_error_description returns a string representation of |err|, where |err|
571 // is one of the |SSL_ERROR_*| constants returned by |SSL_get_error|, or NULL
572 // if the value is unrecognized.
573 OPENSSL_EXPORT const char *SSL_error_description(int err);
574 
575 // SSL_set_mtu sets the |ssl|'s MTU in DTLS to |mtu|. It returns one on success
576 // and zero on failure.
577 OPENSSL_EXPORT int SSL_set_mtu(SSL *ssl, unsigned mtu);
578 
579 // DTLSv1_set_initial_timeout_duration sets the initial duration for a DTLS
580 // handshake timeout.
581 //
582 // This duration overrides the default of 1 second, which is the strong
583 // recommendation of RFC 6347 (see section 4.2.4.1). However, there may exist
584 // situations where a shorter timeout would be beneficial, such as for
585 // time-sensitive applications.
586 OPENSSL_EXPORT void DTLSv1_set_initial_timeout_duration(SSL *ssl,
587                                                         unsigned duration_ms);
588 
589 // DTLSv1_get_timeout queries the next DTLS handshake timeout. If there is a
590 // timeout in progress, it sets |*out| to the time remaining and returns one.
591 // Otherwise, it returns zero.
592 //
593 // When the timeout expires, call |DTLSv1_handle_timeout| to handle the
594 // retransmit behavior.
595 //
596 // NOTE: This function must be queried again whenever the handshake state
597 // machine changes, including when |DTLSv1_handle_timeout| is called.
598 OPENSSL_EXPORT int DTLSv1_get_timeout(const SSL *ssl, struct timeval *out);
599 
600 // DTLSv1_handle_timeout is called when a DTLS handshake timeout expires. If no
601 // timeout had expired, it returns 0. Otherwise, it retransmits the previous
602 // flight of handshake messages and returns 1. If too many timeouts had expired
603 // without progress or an error occurs, it returns -1.
604 //
605 // The caller's external timer should be compatible with the one |ssl| queries
606 // within some fudge factor. Otherwise, the call will be a no-op, but
607 // |DTLSv1_get_timeout| will return an updated timeout.
608 //
609 // If the function returns -1, checking if |SSL_get_error| returns
610 // |SSL_ERROR_WANT_WRITE| may be used to determine if the retransmit failed due
611 // to a non-fatal error at the write |BIO|. However, the operation may not be
612 // retried until the next timeout fires.
613 //
614 // WARNING: This function breaks the usual return value convention.
615 //
616 // TODO(davidben): This |SSL_ERROR_WANT_WRITE| behavior is kind of bizarre.
617 OPENSSL_EXPORT int DTLSv1_handle_timeout(SSL *ssl);
618 
619 
620 // Protocol versions.
621 
622 #define DTLS1_VERSION_MAJOR 0xfe
623 #define SSL3_VERSION_MAJOR 0x03
624 
625 #define SSL3_VERSION 0x0300
626 #define TLS1_VERSION 0x0301
627 #define TLS1_1_VERSION 0x0302
628 #define TLS1_2_VERSION 0x0303
629 #define TLS1_3_VERSION 0x0304
630 
631 #define DTLS1_VERSION 0xfeff
632 #define DTLS1_2_VERSION 0xfefd
633 
634 // SSL_CTX_set_min_proto_version sets the minimum protocol version for |ctx| to
635 // |version|. If |version| is zero, the default minimum version is used. It
636 // returns one on success and zero if |version| is invalid.
637 OPENSSL_EXPORT int SSL_CTX_set_min_proto_version(SSL_CTX *ctx,
638                                                  uint16_t version);
639 
640 // SSL_CTX_set_max_proto_version sets the maximum protocol version for |ctx| to
641 // |version|. If |version| is zero, the default maximum version is used. It
642 // returns one on success and zero if |version| is invalid.
643 OPENSSL_EXPORT int SSL_CTX_set_max_proto_version(SSL_CTX *ctx,
644                                                  uint16_t version);
645 
646 // SSL_CTX_get_min_proto_version returns the minimum protocol version for |ctx|
647 OPENSSL_EXPORT uint16_t SSL_CTX_get_min_proto_version(const SSL_CTX *ctx);
648 
649 // SSL_CTX_get_max_proto_version returns the maximum protocol version for |ctx|
650 OPENSSL_EXPORT uint16_t SSL_CTX_get_max_proto_version(const SSL_CTX *ctx);
651 
652 // SSL_set_min_proto_version sets the minimum protocol version for |ssl| to
653 // |version|. If |version| is zero, the default minimum version is used. It
654 // returns one on success and zero if |version| is invalid.
655 OPENSSL_EXPORT int SSL_set_min_proto_version(SSL *ssl, uint16_t version);
656 
657 // SSL_set_max_proto_version sets the maximum protocol version for |ssl| to
658 // |version|. If |version| is zero, the default maximum version is used. It
659 // returns one on success and zero if |version| is invalid.
660 OPENSSL_EXPORT int SSL_set_max_proto_version(SSL *ssl, uint16_t version);
661 
662 // SSL_get_min_proto_version returns the minimum protocol version for |ssl|. If
663 // the connection's configuration has been shed, 0 is returned.
664 OPENSSL_EXPORT uint16_t SSL_get_min_proto_version(const SSL *ssl);
665 
666 // SSL_get_max_proto_version returns the maximum protocol version for |ssl|. If
667 // the connection's configuration has been shed, 0 is returned.
668 OPENSSL_EXPORT uint16_t SSL_get_max_proto_version(const SSL *ssl);
669 
670 // SSL_version returns the TLS or DTLS protocol version used by |ssl|, which is
671 // one of the |*_VERSION| values. (E.g. |TLS1_2_VERSION|.) Before the version
672 // is negotiated, the result is undefined.
673 OPENSSL_EXPORT int SSL_version(const SSL *ssl);
674 
675 
676 // Options.
677 //
678 // Options configure protocol behavior.
679 
680 // SSL_OP_NO_QUERY_MTU, in DTLS, disables querying the MTU from the underlying
681 // |BIO|. Instead, the MTU is configured with |SSL_set_mtu|.
682 #define SSL_OP_NO_QUERY_MTU 0x00001000L
683 
684 // SSL_OP_NO_TICKET disables session ticket support (RFC 5077).
685 #define SSL_OP_NO_TICKET 0x00004000L
686 
687 // SSL_OP_CIPHER_SERVER_PREFERENCE configures servers to select ciphers and
688 // ECDHE curves according to the server's preferences instead of the
689 // client's.
690 #define SSL_OP_CIPHER_SERVER_PREFERENCE 0x00400000L
691 
692 // The following flags toggle individual protocol versions. This is deprecated.
693 // Use |SSL_CTX_set_min_proto_version| and |SSL_CTX_set_max_proto_version|
694 // instead.
695 #define SSL_OP_NO_TLSv1 0x04000000L
696 #define SSL_OP_NO_TLSv1_2 0x08000000L
697 #define SSL_OP_NO_TLSv1_1 0x10000000L
698 #define SSL_OP_NO_TLSv1_3 0x20000000L
699 #define SSL_OP_NO_DTLSv1 SSL_OP_NO_TLSv1
700 #define SSL_OP_NO_DTLSv1_2 SSL_OP_NO_TLSv1_2
701 
702 // SSL_CTX_set_options enables all options set in |options| (which should be one
703 // or more of the |SSL_OP_*| values, ORed together) in |ctx|. It returns a
704 // bitmask representing the resulting enabled options.
705 OPENSSL_EXPORT uint32_t SSL_CTX_set_options(SSL_CTX *ctx, uint32_t options);
706 
707 // SSL_CTX_clear_options disables all options set in |options| (which should be
708 // one or more of the |SSL_OP_*| values, ORed together) in |ctx|. It returns a
709 // bitmask representing the resulting enabled options.
710 OPENSSL_EXPORT uint32_t SSL_CTX_clear_options(SSL_CTX *ctx, uint32_t options);
711 
712 // SSL_CTX_get_options returns a bitmask of |SSL_OP_*| values that represent all
713 // the options enabled for |ctx|.
714 OPENSSL_EXPORT uint32_t SSL_CTX_get_options(const SSL_CTX *ctx);
715 
716 // SSL_set_options enables all options set in |options| (which should be one or
717 // more of the |SSL_OP_*| values, ORed together) in |ssl|. It returns a bitmask
718 // representing the resulting enabled options.
719 OPENSSL_EXPORT uint32_t SSL_set_options(SSL *ssl, uint32_t options);
720 
721 // SSL_clear_options disables all options set in |options| (which should be one
722 // or more of the |SSL_OP_*| values, ORed together) in |ssl|. It returns a
723 // bitmask representing the resulting enabled options.
724 OPENSSL_EXPORT uint32_t SSL_clear_options(SSL *ssl, uint32_t options);
725 
726 // SSL_get_options returns a bitmask of |SSL_OP_*| values that represent all the
727 // options enabled for |ssl|.
728 OPENSSL_EXPORT uint32_t SSL_get_options(const SSL *ssl);
729 
730 
731 // Modes.
732 //
733 // Modes configure API behavior.
734 
735 // SSL_MODE_ENABLE_PARTIAL_WRITE, in TLS, allows |SSL_write| to complete with a
736 // partial result when the only part of the input was written in a single
737 // record. In DTLS, it does nothing.
738 #define SSL_MODE_ENABLE_PARTIAL_WRITE 0x00000001L
739 
740 // SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER, in TLS, allows retrying an incomplete
741 // |SSL_write| with a different buffer. However, |SSL_write| still assumes the
742 // buffer contents are unchanged. This is not the default to avoid the
743 // misconception that non-blocking |SSL_write| behaves like non-blocking
744 // |write|. In DTLS, it does nothing.
745 #define SSL_MODE_ACCEPT_MOVING_WRITE_BUFFER 0x00000002L
746 
747 // SSL_MODE_NO_AUTO_CHAIN disables automatically building a certificate chain
748 // before sending certificates to the peer. This flag is set (and the feature
749 // disabled) by default.
750 // TODO(davidben): Remove this behavior. https://crbug.com/boringssl/42.
751 #define SSL_MODE_NO_AUTO_CHAIN 0x00000008L
752 
753 // SSL_MODE_ENABLE_FALSE_START allows clients to send application data before
754 // receipt of ChangeCipherSpec and Finished. This mode enables full handshakes
755 // to 'complete' in one RTT. See RFC 7918.
756 //
757 // When False Start is enabled, |SSL_do_handshake| may succeed before the
758 // handshake has completely finished. |SSL_write| will function at this point,
759 // and |SSL_read| will transparently wait for the final handshake leg before
760 // returning application data. To determine if False Start occurred or when the
761 // handshake is completely finished, see |SSL_in_false_start|, |SSL_in_init|,
762 // and |SSL_CB_HANDSHAKE_DONE| from |SSL_CTX_set_info_callback|.
763 #define SSL_MODE_ENABLE_FALSE_START 0x00000080L
764 
765 // SSL_MODE_CBC_RECORD_SPLITTING causes multi-byte CBC records in TLS 1.0 to be
766 // split in two: the first record will contain a single byte and the second will
767 // contain the remainder. This effectively randomises the IV and prevents BEAST
768 // attacks.
769 #define SSL_MODE_CBC_RECORD_SPLITTING 0x00000100L
770 
771 // SSL_MODE_NO_SESSION_CREATION will cause any attempts to create a session to
772 // fail with SSL_R_SESSION_MAY_NOT_BE_CREATED. This can be used to enforce that
773 // session resumption is used for a given SSL*.
774 #define SSL_MODE_NO_SESSION_CREATION 0x00000200L
775 
776 // SSL_MODE_SEND_FALLBACK_SCSV sends TLS_FALLBACK_SCSV in the ClientHello.
777 // To be set only by applications that reconnect with a downgraded protocol
778 // version; see RFC 7507 for details.
779 //
780 // DO NOT ENABLE THIS if your application attempts a normal handshake. Only use
781 // this in explicit fallback retries, following the guidance in RFC 7507.
782 #define SSL_MODE_SEND_FALLBACK_SCSV 0x00000400L
783 
784 // SSL_CTX_set_mode enables all modes set in |mode| (which should be one or more
785 // of the |SSL_MODE_*| values, ORed together) in |ctx|. It returns a bitmask
786 // representing the resulting enabled modes.
787 OPENSSL_EXPORT uint32_t SSL_CTX_set_mode(SSL_CTX *ctx, uint32_t mode);
788 
789 // SSL_CTX_clear_mode disables all modes set in |mode| (which should be one or
790 // more of the |SSL_MODE_*| values, ORed together) in |ctx|. It returns a
791 // bitmask representing the resulting enabled modes.
792 OPENSSL_EXPORT uint32_t SSL_CTX_clear_mode(SSL_CTX *ctx, uint32_t mode);
793 
794 // SSL_CTX_get_mode returns a bitmask of |SSL_MODE_*| values that represent all
795 // the modes enabled for |ssl|.
796 OPENSSL_EXPORT uint32_t SSL_CTX_get_mode(const SSL_CTX *ctx);
797 
798 // SSL_set_mode enables all modes set in |mode| (which should be one or more of
799 // the |SSL_MODE_*| values, ORed together) in |ssl|. It returns a bitmask
800 // representing the resulting enabled modes.
801 OPENSSL_EXPORT uint32_t SSL_set_mode(SSL *ssl, uint32_t mode);
802 
803 // SSL_clear_mode disables all modes set in |mode| (which should be one or more
804 // of the |SSL_MODE_*| values, ORed together) in |ssl|. It returns a bitmask
805 // representing the resulting enabled modes.
806 OPENSSL_EXPORT uint32_t SSL_clear_mode(SSL *ssl, uint32_t mode);
807 
808 // SSL_get_mode returns a bitmask of |SSL_MODE_*| values that represent all the
809 // modes enabled for |ssl|.
810 OPENSSL_EXPORT uint32_t SSL_get_mode(const SSL *ssl);
811 
812 // SSL_CTX_set0_buffer_pool sets a |CRYPTO_BUFFER_POOL| that will be used to
813 // store certificates. This can allow multiple connections to share
814 // certificates and thus save memory.
815 //
816 // The SSL_CTX does not take ownership of |pool| and the caller must ensure
817 // that |pool| outlives |ctx| and all objects linked to it, including |SSL|,
818 // |X509| and |SSL_SESSION| objects. Basically, don't ever free |pool|.
819 OPENSSL_EXPORT void SSL_CTX_set0_buffer_pool(SSL_CTX *ctx,
820                                              CRYPTO_BUFFER_POOL *pool);
821 
822 
823 // Configuring certificates and private keys.
824 //
825 // These functions configure the connection's leaf certificate, private key, and
826 // certificate chain. The certificate chain is ordered leaf to root (as sent on
827 // the wire) but does not include the leaf. Both client and server certificates
828 // use these functions.
829 //
830 // Certificates and keys may be configured before the handshake or dynamically
831 // in the early callback and certificate callback.
832 
833 // SSL_CTX_use_certificate sets |ctx|'s leaf certificate to |x509|. It returns
834 // one on success and zero on failure.
835 OPENSSL_EXPORT int SSL_CTX_use_certificate(SSL_CTX *ctx, X509 *x509);
836 
837 // SSL_use_certificate sets |ssl|'s leaf certificate to |x509|. It returns one
838 // on success and zero on failure.
839 OPENSSL_EXPORT int SSL_use_certificate(SSL *ssl, X509 *x509);
840 
841 // SSL_CTX_use_PrivateKey sets |ctx|'s private key to |pkey|. It returns one on
842 // success and zero on failure.
843 OPENSSL_EXPORT int SSL_CTX_use_PrivateKey(SSL_CTX *ctx, EVP_PKEY *pkey);
844 
845 // SSL_use_PrivateKey sets |ssl|'s private key to |pkey|. It returns one on
846 // success and zero on failure.
847 OPENSSL_EXPORT int SSL_use_PrivateKey(SSL *ssl, EVP_PKEY *pkey);
848 
849 // SSL_CTX_set0_chain sets |ctx|'s certificate chain, excluding the leaf, to
850 // |chain|. On success, it returns one and takes ownership of |chain|.
851 // Otherwise, it returns zero.
852 OPENSSL_EXPORT int SSL_CTX_set0_chain(SSL_CTX *ctx, STACK_OF(X509) *chain);
853 
854 // SSL_CTX_set1_chain sets |ctx|'s certificate chain, excluding the leaf, to
855 // |chain|. It returns one on success and zero on failure. The caller retains
856 // ownership of |chain| and may release it freely.
857 OPENSSL_EXPORT int SSL_CTX_set1_chain(SSL_CTX *ctx, STACK_OF(X509) *chain);
858 
859 // SSL_set0_chain sets |ssl|'s certificate chain, excluding the leaf, to
860 // |chain|. On success, it returns one and takes ownership of |chain|.
861 // Otherwise, it returns zero.
862 OPENSSL_EXPORT int SSL_set0_chain(SSL *ssl, STACK_OF(X509) *chain);
863 
864 // SSL_set1_chain sets |ssl|'s certificate chain, excluding the leaf, to
865 // |chain|. It returns one on success and zero on failure. The caller retains
866 // ownership of |chain| and may release it freely.
867 OPENSSL_EXPORT int SSL_set1_chain(SSL *ssl, STACK_OF(X509) *chain);
868 
869 // SSL_CTX_add0_chain_cert appends |x509| to |ctx|'s certificate chain. On
870 // success, it returns one and takes ownership of |x509|. Otherwise, it returns
871 // zero.
872 OPENSSL_EXPORT int SSL_CTX_add0_chain_cert(SSL_CTX *ctx, X509 *x509);
873 
874 // SSL_CTX_add1_chain_cert appends |x509| to |ctx|'s certificate chain. It
875 // returns one on success and zero on failure. The caller retains ownership of
876 // |x509| and may release it freely.
877 OPENSSL_EXPORT int SSL_CTX_add1_chain_cert(SSL_CTX *ctx, X509 *x509);
878 
879 // SSL_add0_chain_cert appends |x509| to |ctx|'s certificate chain. On success,
880 // it returns one and takes ownership of |x509|. Otherwise, it returns zero.
881 OPENSSL_EXPORT int SSL_add0_chain_cert(SSL *ssl, X509 *x509);
882 
883 // SSL_CTX_add_extra_chain_cert calls |SSL_CTX_add0_chain_cert|.
884 OPENSSL_EXPORT int SSL_CTX_add_extra_chain_cert(SSL_CTX *ctx, X509 *x509);
885 
886 // SSL_add1_chain_cert appends |x509| to |ctx|'s certificate chain. It returns
887 // one on success and zero on failure. The caller retains ownership of |x509|
888 // and may release it freely.
889 OPENSSL_EXPORT int SSL_add1_chain_cert(SSL *ssl, X509 *x509);
890 
891 // SSL_CTX_clear_chain_certs clears |ctx|'s certificate chain and returns
892 // one.
893 OPENSSL_EXPORT int SSL_CTX_clear_chain_certs(SSL_CTX *ctx);
894 
895 // SSL_CTX_clear_extra_chain_certs calls |SSL_CTX_clear_chain_certs|.
896 OPENSSL_EXPORT int SSL_CTX_clear_extra_chain_certs(SSL_CTX *ctx);
897 
898 // SSL_clear_chain_certs clears |ssl|'s certificate chain and returns one.
899 OPENSSL_EXPORT int SSL_clear_chain_certs(SSL *ssl);
900 
901 // SSL_CTX_set_cert_cb sets a callback that is called to select a certificate.
902 // The callback returns one on success, zero on internal error, and a negative
903 // number on failure or to pause the handshake. If the handshake is paused,
904 // |SSL_get_error| will return |SSL_ERROR_WANT_X509_LOOKUP|.
905 //
906 // On the client, the callback may call |SSL_get0_certificate_types| and
907 // |SSL_get_client_CA_list| for information on the server's certificate
908 // request.
909 //
910 // On the server, the callback will be called after extensions have been
911 // processed, but before the resumption decision has been made. This differs
912 // from OpenSSL which handles resumption before selecting the certificate.
913 OPENSSL_EXPORT void SSL_CTX_set_cert_cb(SSL_CTX *ctx,
914                                         int (*cb)(SSL *ssl, void *arg),
915                                         void *arg);
916 
917 // SSL_set_cert_cb sets a callback that is called to select a certificate. The
918 // callback returns one on success, zero on internal error, and a negative
919 // number on failure or to pause the handshake. If the handshake is paused,
920 // |SSL_get_error| will return |SSL_ERROR_WANT_X509_LOOKUP|.
921 //
922 // On the client, the callback may call |SSL_get0_certificate_types| and
923 // |SSL_get_client_CA_list| for information on the server's certificate
924 // request.
925 //
926 // On the server, the callback will be called after extensions have been
927 // processed, but before the resumption decision has been made. This differs
928 // from OpenSSL which handles resumption before selecting the certificate.
929 OPENSSL_EXPORT void SSL_set_cert_cb(SSL *ssl, int (*cb)(SSL *ssl, void *arg),
930                                     void *arg);
931 
932 // SSL_get0_certificate_types, for a client, sets |*out_types| to an array
933 // containing the client certificate types requested by a server. It returns the
934 // length of the array. Note this list is always empty in TLS 1.3. The server
935 // will instead send signature algorithms. See
936 // |SSL_get0_peer_verify_algorithms|.
937 //
938 // The behavior of this function is undefined except during the callbacks set by
939 // by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
940 // handshake is paused because of them.
941 OPENSSL_EXPORT size_t SSL_get0_certificate_types(const SSL *ssl,
942                                                  const uint8_t **out_types);
943 
944 // SSL_get0_peer_verify_algorithms sets |*out_sigalgs| to an array containing
945 // the signature algorithms the peer is able to verify. It returns the length of
946 // the array. Note these values are only sent starting TLS 1.2 and only
947 // mandatory starting TLS 1.3. If not sent, the empty array is returned. For the
948 // historical client certificate types list, see |SSL_get0_certificate_types|.
949 //
950 // The behavior of this function is undefined except during the callbacks set by
951 // by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
952 // handshake is paused because of them.
953 OPENSSL_EXPORT size_t
954 SSL_get0_peer_verify_algorithms(const SSL *ssl, const uint16_t **out_sigalgs);
955 
956 // SSL_get0_peer_delegation_algorithms sets |*out_sigalgs| to an array
957 // containing the signature algorithms the peer is willing to use with delegated
958 // credentials.  It returns the length of the array. If not sent, the empty
959 // array is returned.
960 //
961 // The behavior of this function is undefined except during the callbacks set by
962 // by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or when the
963 // handshake is paused because of them.
964 OPENSSL_EXPORT size_t
965 SSL_get0_peer_delegation_algorithms(const SSL *ssl,
966                                     const uint16_t **out_sigalgs);
967 
968 // SSL_certs_clear resets the private key, leaf certificate, and certificate
969 // chain of |ssl|.
970 OPENSSL_EXPORT void SSL_certs_clear(SSL *ssl);
971 
972 // SSL_CTX_check_private_key returns one if the certificate and private key
973 // configured in |ctx| are consistent and zero otherwise.
974 OPENSSL_EXPORT int SSL_CTX_check_private_key(const SSL_CTX *ctx);
975 
976 // SSL_check_private_key returns one if the certificate and private key
977 // configured in |ssl| are consistent and zero otherwise.
978 OPENSSL_EXPORT int SSL_check_private_key(const SSL *ssl);
979 
980 // SSL_CTX_get0_certificate returns |ctx|'s leaf certificate.
981 OPENSSL_EXPORT X509 *SSL_CTX_get0_certificate(const SSL_CTX *ctx);
982 
983 // SSL_get_certificate returns |ssl|'s leaf certificate.
984 OPENSSL_EXPORT X509 *SSL_get_certificate(const SSL *ssl);
985 
986 // SSL_CTX_get0_privatekey returns |ctx|'s private key.
987 OPENSSL_EXPORT EVP_PKEY *SSL_CTX_get0_privatekey(const SSL_CTX *ctx);
988 
989 // SSL_get_privatekey returns |ssl|'s private key.
990 OPENSSL_EXPORT EVP_PKEY *SSL_get_privatekey(const SSL *ssl);
991 
992 // SSL_CTX_get0_chain_certs sets |*out_chain| to |ctx|'s certificate chain and
993 // returns one.
994 OPENSSL_EXPORT int SSL_CTX_get0_chain_certs(const SSL_CTX *ctx,
995                                             STACK_OF(X509) **out_chain);
996 
997 // SSL_CTX_get_extra_chain_certs calls |SSL_CTX_get0_chain_certs|.
998 OPENSSL_EXPORT int SSL_CTX_get_extra_chain_certs(const SSL_CTX *ctx,
999                                                  STACK_OF(X509) **out_chain);
1000 
1001 // SSL_get0_chain_certs sets |*out_chain| to |ssl|'s certificate chain and
1002 // returns one.
1003 OPENSSL_EXPORT int SSL_get0_chain_certs(const SSL *ssl,
1004                                         STACK_OF(X509) **out_chain);
1005 
1006 // SSL_CTX_set_signed_cert_timestamp_list sets the list of signed certificate
1007 // timestamps that is sent to clients that request it. The |list| argument must
1008 // contain one or more SCT structures serialised as a SignedCertificateTimestamp
1009 // List (see https://tools.ietf.org/html/rfc6962#section-3.3) – i.e. each SCT
1010 // is prefixed by a big-endian, uint16 length and the concatenation of one or
1011 // more such prefixed SCTs are themselves also prefixed by a uint16 length. It
1012 // returns one on success and zero on error. The caller retains ownership of
1013 // |list|.
1014 OPENSSL_EXPORT int SSL_CTX_set_signed_cert_timestamp_list(SSL_CTX *ctx,
1015                                                           const uint8_t *list,
1016                                                           size_t list_len);
1017 
1018 // SSL_set_signed_cert_timestamp_list sets the list of signed certificate
1019 // timestamps that is sent to clients that request is. The same format as the
1020 // one used for |SSL_CTX_set_signed_cert_timestamp_list| applies. The caller
1021 // retains ownership of |list|.
1022 OPENSSL_EXPORT int SSL_set_signed_cert_timestamp_list(SSL *ctx,
1023                                                       const uint8_t *list,
1024                                                       size_t list_len);
1025 
1026 // SSL_CTX_set_ocsp_response sets the OCSP response that is sent to clients
1027 // which request it. It returns one on success and zero on error. The caller
1028 // retains ownership of |response|.
1029 OPENSSL_EXPORT int SSL_CTX_set_ocsp_response(SSL_CTX *ctx,
1030                                              const uint8_t *response,
1031                                              size_t response_len);
1032 
1033 // SSL_set_ocsp_response sets the OCSP response that is sent to clients which
1034 // request it. It returns one on success and zero on error. The caller retains
1035 // ownership of |response|.
1036 OPENSSL_EXPORT int SSL_set_ocsp_response(SSL *ssl,
1037                                          const uint8_t *response,
1038                                          size_t response_len);
1039 
1040 // SSL_SIGN_* are signature algorithm values as defined in TLS 1.3.
1041 #define SSL_SIGN_RSA_PKCS1_SHA1 0x0201
1042 #define SSL_SIGN_RSA_PKCS1_SHA256 0x0401
1043 #define SSL_SIGN_RSA_PKCS1_SHA384 0x0501
1044 #define SSL_SIGN_RSA_PKCS1_SHA512 0x0601
1045 #define SSL_SIGN_ECDSA_SHA1 0x0203
1046 #define SSL_SIGN_ECDSA_SECP256R1_SHA256 0x0403
1047 #define SSL_SIGN_ECDSA_SECP384R1_SHA384 0x0503
1048 #define SSL_SIGN_ECDSA_SECP521R1_SHA512 0x0603
1049 #define SSL_SIGN_RSA_PSS_RSAE_SHA256 0x0804
1050 #define SSL_SIGN_RSA_PSS_RSAE_SHA384 0x0805
1051 #define SSL_SIGN_RSA_PSS_RSAE_SHA512 0x0806
1052 #define SSL_SIGN_ED25519 0x0807
1053 
1054 // SSL_SIGN_RSA_PKCS1_MD5_SHA1 is an internal signature algorithm used to
1055 // specify raw RSASSA-PKCS1-v1_5 with an MD5/SHA-1 concatenation, as used in TLS
1056 // before TLS 1.2.
1057 #define SSL_SIGN_RSA_PKCS1_MD5_SHA1 0xff01
1058 
1059 // SSL_get_signature_algorithm_name returns a human-readable name for |sigalg|,
1060 // or NULL if unknown. If |include_curve| is one, the curve for ECDSA algorithms
1061 // is included as in TLS 1.3. Otherwise, it is excluded as in TLS 1.2.
1062 OPENSSL_EXPORT const char *SSL_get_signature_algorithm_name(uint16_t sigalg,
1063                                                             int include_curve);
1064 
1065 // SSL_get_signature_algorithm_key_type returns the key type associated with
1066 // |sigalg| as an |EVP_PKEY_*| constant or |EVP_PKEY_NONE| if unknown.
1067 OPENSSL_EXPORT int SSL_get_signature_algorithm_key_type(uint16_t sigalg);
1068 
1069 // SSL_get_signature_algorithm_digest returns the digest function associated
1070 // with |sigalg| or |NULL| if |sigalg| has no prehash (Ed25519) or is unknown.
1071 OPENSSL_EXPORT const EVP_MD *SSL_get_signature_algorithm_digest(
1072     uint16_t sigalg);
1073 
1074 // SSL_is_signature_algorithm_rsa_pss returns one if |sigalg| is an RSA-PSS
1075 // signature algorithm and zero otherwise.
1076 OPENSSL_EXPORT int SSL_is_signature_algorithm_rsa_pss(uint16_t sigalg);
1077 
1078 // SSL_CTX_set_signing_algorithm_prefs configures |ctx| to use |prefs| as the
1079 // preference list when signing with |ctx|'s private key. It returns one on
1080 // success and zero on error. |prefs| should not include the internal-only value
1081 // |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
1082 OPENSSL_EXPORT int SSL_CTX_set_signing_algorithm_prefs(SSL_CTX *ctx,
1083                                                        const uint16_t *prefs,
1084                                                        size_t num_prefs);
1085 
1086 // SSL_set_signing_algorithm_prefs configures |ssl| to use |prefs| as the
1087 // preference list when signing with |ssl|'s private key. It returns one on
1088 // success and zero on error. |prefs| should not include the internal-only value
1089 // |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
1090 OPENSSL_EXPORT int SSL_set_signing_algorithm_prefs(SSL *ssl,
1091                                                    const uint16_t *prefs,
1092                                                    size_t num_prefs);
1093 
1094 
1095 // Certificate and private key convenience functions.
1096 
1097 // SSL_CTX_set_chain_and_key sets the certificate chain and private key for a
1098 // TLS client or server. References to the given |CRYPTO_BUFFER| and |EVP_PKEY|
1099 // objects are added as needed. Exactly one of |privkey| or |privkey_method|
1100 // may be non-NULL. Returns one on success and zero on error.
1101 OPENSSL_EXPORT int SSL_CTX_set_chain_and_key(
1102     SSL_CTX *ctx, CRYPTO_BUFFER *const *certs, size_t num_certs,
1103     EVP_PKEY *privkey, const SSL_PRIVATE_KEY_METHOD *privkey_method);
1104 
1105 // SSL_set_chain_and_key sets the certificate chain and private key for a TLS
1106 // client or server. References to the given |CRYPTO_BUFFER| and |EVP_PKEY|
1107 // objects are added as needed. Exactly one of |privkey| or |privkey_method|
1108 // may be non-NULL. Returns one on success and zero on error.
1109 OPENSSL_EXPORT int SSL_set_chain_and_key(
1110     SSL *ssl, CRYPTO_BUFFER *const *certs, size_t num_certs, EVP_PKEY *privkey,
1111     const SSL_PRIVATE_KEY_METHOD *privkey_method);
1112 
1113 // SSL_CTX_get0_chain returns the list of |CRYPTO_BUFFER|s that were set by
1114 // |SSL_CTX_set_chain_and_key|. Reference counts are not incremented by this
1115 // call. The return value may be |NULL| if no chain has been set.
1116 //
1117 // (Note: if a chain was configured by non-|CRYPTO_BUFFER|-based functions then
1118 // the return value is undefined and, even if not NULL, the stack itself may
1119 // contain nullptrs. Thus you shouldn't mix this function with
1120 // non-|CRYPTO_BUFFER| functions for manipulating the chain.)
1121 //
1122 // There is no |SSL*| version of this function because connections discard
1123 // configuration after handshaking, thus making it of questionable utility.
1124 OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER)*
1125     SSL_CTX_get0_chain(const SSL_CTX *ctx);
1126 
1127 // SSL_CTX_use_RSAPrivateKey sets |ctx|'s private key to |rsa|. It returns one
1128 // on success and zero on failure.
1129 OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey(SSL_CTX *ctx, RSA *rsa);
1130 
1131 // SSL_use_RSAPrivateKey sets |ctx|'s private key to |rsa|. It returns one on
1132 // success and zero on failure.
1133 OPENSSL_EXPORT int SSL_use_RSAPrivateKey(SSL *ssl, RSA *rsa);
1134 
1135 // The following functions configure certificates or private keys but take as
1136 // input DER-encoded structures. They return one on success and zero on
1137 // failure.
1138 
1139 OPENSSL_EXPORT int SSL_CTX_use_certificate_ASN1(SSL_CTX *ctx, size_t der_len,
1140                                                 const uint8_t *der);
1141 OPENSSL_EXPORT int SSL_use_certificate_ASN1(SSL *ssl, const uint8_t *der,
1142                                             size_t der_len);
1143 
1144 OPENSSL_EXPORT int SSL_CTX_use_PrivateKey_ASN1(int pk, SSL_CTX *ctx,
1145                                                const uint8_t *der,
1146                                                size_t der_len);
1147 OPENSSL_EXPORT int SSL_use_PrivateKey_ASN1(int type, SSL *ssl,
1148                                            const uint8_t *der, size_t der_len);
1149 
1150 OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey_ASN1(SSL_CTX *ctx,
1151                                                   const uint8_t *der,
1152                                                   size_t der_len);
1153 OPENSSL_EXPORT int SSL_use_RSAPrivateKey_ASN1(SSL *ssl, const uint8_t *der,
1154                                               size_t der_len);
1155 
1156 // The following functions configure certificates or private keys but take as
1157 // input files to read from. They return one on success and zero on failure. The
1158 // |type| parameter is one of the |SSL_FILETYPE_*| values and determines whether
1159 // the file's contents are read as PEM or DER.
1160 
1161 #define SSL_FILETYPE_PEM 1
1162 #define SSL_FILETYPE_ASN1 2
1163 
1164 OPENSSL_EXPORT int SSL_CTX_use_RSAPrivateKey_file(SSL_CTX *ctx,
1165                                                   const char *file,
1166                                                   int type);
1167 OPENSSL_EXPORT int SSL_use_RSAPrivateKey_file(SSL *ssl, const char *file,
1168                                               int type);
1169 
1170 OPENSSL_EXPORT int SSL_CTX_use_certificate_file(SSL_CTX *ctx, const char *file,
1171                                                 int type);
1172 OPENSSL_EXPORT int SSL_use_certificate_file(SSL *ssl, const char *file,
1173                                             int type);
1174 
1175 OPENSSL_EXPORT int SSL_CTX_use_PrivateKey_file(SSL_CTX *ctx, const char *file,
1176                                                int type);
1177 OPENSSL_EXPORT int SSL_use_PrivateKey_file(SSL *ssl, const char *file,
1178                                            int type);
1179 
1180 // SSL_CTX_use_certificate_chain_file configures certificates for |ctx|. It
1181 // reads the contents of |file| as a PEM-encoded leaf certificate followed
1182 // optionally by the certificate chain to send to the peer. It returns one on
1183 // success and zero on failure.
1184 OPENSSL_EXPORT int SSL_CTX_use_certificate_chain_file(SSL_CTX *ctx,
1185                                                       const char *file);
1186 
1187 // SSL_CTX_set_default_passwd_cb sets the password callback for PEM-based
1188 // convenience functions called on |ctx|.
1189 OPENSSL_EXPORT void SSL_CTX_set_default_passwd_cb(SSL_CTX *ctx,
1190                                                   pem_password_cb *cb);
1191 
1192 // SSL_CTX_get_default_passwd_cb returns the callback set by
1193 // |SSL_CTX_set_default_passwd_cb|.
1194 OPENSSL_EXPORT pem_password_cb *SSL_CTX_get_default_passwd_cb(
1195     const SSL_CTX *ctx);
1196 
1197 // SSL_CTX_set_default_passwd_cb_userdata sets the userdata parameter for
1198 // |ctx|'s password callback.
1199 OPENSSL_EXPORT void SSL_CTX_set_default_passwd_cb_userdata(SSL_CTX *ctx,
1200                                                            void *data);
1201 
1202 // SSL_CTX_get_default_passwd_cb_userdata returns the userdata parameter set by
1203 // |SSL_CTX_set_default_passwd_cb_userdata|.
1204 OPENSSL_EXPORT void *SSL_CTX_get_default_passwd_cb_userdata(const SSL_CTX *ctx);
1205 
1206 
1207 // Custom private keys.
1208 
1209 enum ssl_private_key_result_t BORINGSSL_ENUM_INT {
1210   ssl_private_key_success,
1211   ssl_private_key_retry,
1212   ssl_private_key_failure,
1213 };
1214 
1215 // ssl_private_key_method_st (aka |SSL_PRIVATE_KEY_METHOD|) describes private
1216 // key hooks. This is used to off-load signing operations to a custom,
1217 // potentially asynchronous, backend. Metadata about the key such as the type
1218 // and size are parsed out of the certificate.
1219 struct ssl_private_key_method_st {
1220   // sign signs the message |in| in using the specified signature algorithm. On
1221   // success, it returns |ssl_private_key_success| and writes at most |max_out|
1222   // bytes of signature data to |out| and sets |*out_len| to the number of bytes
1223   // written. On failure, it returns |ssl_private_key_failure|. If the operation
1224   // has not completed, it returns |ssl_private_key_retry|. |sign| should
1225   // arrange for the high-level operation on |ssl| to be retried when the
1226   // operation is completed. This will result in a call to |complete|.
1227   //
1228   // |signature_algorithm| is one of the |SSL_SIGN_*| values, as defined in TLS
1229   // 1.3. Note that, in TLS 1.2, ECDSA algorithms do not require that curve
1230   // sizes match hash sizes, so the curve portion of |SSL_SIGN_ECDSA_*| values
1231   // must be ignored. BoringSSL will internally handle the curve matching logic
1232   // where appropriate.
1233   //
1234   // It is an error to call |sign| while another private key operation is in
1235   // progress on |ssl|.
1236   enum ssl_private_key_result_t (*sign)(SSL *ssl, uint8_t *out, size_t *out_len,
1237                                         size_t max_out,
1238                                         uint16_t signature_algorithm,
1239                                         const uint8_t *in, size_t in_len);
1240 
1241   // decrypt decrypts |in_len| bytes of encrypted data from |in|. On success it
1242   // returns |ssl_private_key_success|, writes at most |max_out| bytes of
1243   // decrypted data to |out| and sets |*out_len| to the actual number of bytes
1244   // written. On failure it returns |ssl_private_key_failure|. If the operation
1245   // has not completed, it returns |ssl_private_key_retry|. The caller should
1246   // arrange for the high-level operation on |ssl| to be retried when the
1247   // operation is completed, which will result in a call to |complete|. This
1248   // function only works with RSA keys and should perform a raw RSA decryption
1249   // operation with no padding.
1250   //
1251   // It is an error to call |decrypt| while another private key operation is in
1252   // progress on |ssl|.
1253   enum ssl_private_key_result_t (*decrypt)(SSL *ssl, uint8_t *out,
1254                                            size_t *out_len, size_t max_out,
1255                                            const uint8_t *in, size_t in_len);
1256 
1257   // complete completes a pending operation. If the operation has completed, it
1258   // returns |ssl_private_key_success| and writes the result to |out| as in
1259   // |sign|. Otherwise, it returns |ssl_private_key_failure| on failure and
1260   // |ssl_private_key_retry| if the operation is still in progress.
1261   //
1262   // |complete| may be called arbitrarily many times before completion, but it
1263   // is an error to call |complete| if there is no pending operation in progress
1264   // on |ssl|.
1265   enum ssl_private_key_result_t (*complete)(SSL *ssl, uint8_t *out,
1266                                             size_t *out_len, size_t max_out);
1267 };
1268 
1269 // SSL_set_private_key_method configures a custom private key on |ssl|.
1270 // |key_method| must remain valid for the lifetime of |ssl|.
1271 OPENSSL_EXPORT void SSL_set_private_key_method(
1272     SSL *ssl, const SSL_PRIVATE_KEY_METHOD *key_method);
1273 
1274 // SSL_CTX_set_private_key_method configures a custom private key on |ctx|.
1275 // |key_method| must remain valid for the lifetime of |ctx|.
1276 OPENSSL_EXPORT void SSL_CTX_set_private_key_method(
1277     SSL_CTX *ctx, const SSL_PRIVATE_KEY_METHOD *key_method);
1278 
1279 
1280 // Cipher suites.
1281 //
1282 // |SSL_CIPHER| objects represent cipher suites.
1283 
1284 DEFINE_CONST_STACK_OF(SSL_CIPHER)
1285 
1286 // SSL_get_cipher_by_value returns the structure representing a TLS cipher
1287 // suite based on its assigned number, or NULL if unknown. See
1288 // https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml#tls-parameters-4.
1289 OPENSSL_EXPORT const SSL_CIPHER *SSL_get_cipher_by_value(uint16_t value);
1290 
1291 // SSL_CIPHER_get_id returns |cipher|'s non-IANA id. This is not its
1292 // IANA-assigned number, which is called the "value" here, although it may be
1293 // cast to a |uint16_t| to get it.
1294 OPENSSL_EXPORT uint32_t SSL_CIPHER_get_id(const SSL_CIPHER *cipher);
1295 
1296 // SSL_CIPHER_get_protocol_id returns |cipher|'s IANA-assigned number.
1297 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_protocol_id(const SSL_CIPHER *cipher);
1298 
1299 // SSL_CIPHER_is_aead returns one if |cipher| uses an AEAD cipher.
1300 OPENSSL_EXPORT int SSL_CIPHER_is_aead(const SSL_CIPHER *cipher);
1301 
1302 // SSL_CIPHER_is_block_cipher returns one if |cipher| is a block cipher.
1303 OPENSSL_EXPORT int SSL_CIPHER_is_block_cipher(const SSL_CIPHER *cipher);
1304 
1305 // SSL_CIPHER_get_cipher_nid returns the NID for |cipher|'s bulk
1306 // cipher. Possible values are |NID_aes_128_gcm|, |NID_aes_256_gcm|,
1307 // |NID_chacha20_poly1305|, |NID_aes_128_cbc|, |NID_aes_256_cbc|, and
1308 // |NID_des_ede3_cbc|.
1309 OPENSSL_EXPORT int SSL_CIPHER_get_cipher_nid(const SSL_CIPHER *cipher);
1310 
1311 // SSL_CIPHER_get_digest_nid returns the NID for |cipher|'s HMAC if it is a
1312 // legacy cipher suite. For modern AEAD-based ciphers (see
1313 // |SSL_CIPHER_is_aead|), it returns |NID_undef|.
1314 //
1315 // Note this function only returns the legacy HMAC digest, not the PRF hash.
1316 OPENSSL_EXPORT int SSL_CIPHER_get_digest_nid(const SSL_CIPHER *cipher);
1317 
1318 // SSL_CIPHER_get_kx_nid returns the NID for |cipher|'s key exchange. This may
1319 // be |NID_kx_rsa|, |NID_kx_ecdhe|, or |NID_kx_psk| for TLS 1.2. In TLS 1.3,
1320 // cipher suites do not specify the key exchange, so this function returns
1321 // |NID_kx_any|.
1322 OPENSSL_EXPORT int SSL_CIPHER_get_kx_nid(const SSL_CIPHER *cipher);
1323 
1324 // SSL_CIPHER_get_auth_nid returns the NID for |cipher|'s authentication
1325 // type. This may be |NID_auth_rsa|, |NID_auth_ecdsa|, or |NID_auth_psk| for TLS
1326 // 1.2. In TLS 1.3, cipher suites do not specify authentication, so this
1327 // function returns |NID_auth_any|.
1328 OPENSSL_EXPORT int SSL_CIPHER_get_auth_nid(const SSL_CIPHER *cipher);
1329 
1330 // SSL_CIPHER_get_prf_nid retuns the NID for |cipher|'s PRF hash. If |cipher| is
1331 // a pre-TLS-1.2 cipher, it returns |NID_md5_sha1| but note these ciphers use
1332 // SHA-256 in TLS 1.2. Other return values may be treated uniformly in all
1333 // applicable versions.
1334 OPENSSL_EXPORT int SSL_CIPHER_get_prf_nid(const SSL_CIPHER *cipher);
1335 
1336 // SSL_CIPHER_get_min_version returns the minimum protocol version required
1337 // for |cipher|.
1338 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_min_version(const SSL_CIPHER *cipher);
1339 
1340 // SSL_CIPHER_get_max_version returns the maximum protocol version that
1341 // supports |cipher|.
1342 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_max_version(const SSL_CIPHER *cipher);
1343 
1344 // SSL_CIPHER_standard_name returns the standard IETF name for |cipher|. For
1345 // example, "TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256".
1346 OPENSSL_EXPORT const char *SSL_CIPHER_standard_name(const SSL_CIPHER *cipher);
1347 
1348 // SSL_CIPHER_get_name returns the OpenSSL name of |cipher|. For example,
1349 // "ECDHE-RSA-AES128-GCM-SHA256". Callers are recommended to use
1350 // |SSL_CIPHER_standard_name| instead.
1351 OPENSSL_EXPORT const char *SSL_CIPHER_get_name(const SSL_CIPHER *cipher);
1352 
1353 // SSL_CIPHER_get_kx_name returns a string that describes the key-exchange
1354 // method used by |cipher|. For example, "ECDHE_ECDSA". TLS 1.3 AEAD-only
1355 // ciphers return the string "GENERIC".
1356 OPENSSL_EXPORT const char *SSL_CIPHER_get_kx_name(const SSL_CIPHER *cipher);
1357 
1358 // SSL_CIPHER_get_bits returns the strength, in bits, of |cipher|. If
1359 // |out_alg_bits| is not NULL, it writes the number of bits consumed by the
1360 // symmetric algorithm to |*out_alg_bits|.
1361 OPENSSL_EXPORT int SSL_CIPHER_get_bits(const SSL_CIPHER *cipher,
1362                                        int *out_alg_bits);
1363 
1364 
1365 // Cipher suite configuration.
1366 //
1367 // OpenSSL uses a mini-language to configure cipher suites. The language
1368 // maintains an ordered list of enabled ciphers, along with an ordered list of
1369 // disabled but available ciphers. Initially, all ciphers are disabled with a
1370 // default ordering. The cipher string is then interpreted as a sequence of
1371 // directives, separated by colons, each of which modifies this state.
1372 //
1373 // Most directives consist of a one character or empty opcode followed by a
1374 // selector which matches a subset of available ciphers.
1375 //
1376 // Available opcodes are:
1377 //
1378 //   The empty opcode enables and appends all matching disabled ciphers to the
1379 //   end of the enabled list. The newly appended ciphers are ordered relative to
1380 //   each other matching their order in the disabled list.
1381 //
1382 //   |-| disables all matching enabled ciphers and prepends them to the disabled
1383 //   list, with relative order from the enabled list preserved. This means the
1384 //   most recently disabled ciphers get highest preference relative to other
1385 //   disabled ciphers if re-enabled.
1386 //
1387 //   |+| moves all matching enabled ciphers to the end of the enabled list, with
1388 //   relative order preserved.
1389 //
1390 //   |!| deletes all matching ciphers, enabled or not, from either list. Deleted
1391 //   ciphers will not matched by future operations.
1392 //
1393 // A selector may be a specific cipher (using either the standard or OpenSSL
1394 // name for the cipher) or one or more rules separated by |+|. The final
1395 // selector matches the intersection of each rule. For instance, |AESGCM+aECDSA|
1396 // matches ECDSA-authenticated AES-GCM ciphers.
1397 //
1398 // Available cipher rules are:
1399 //
1400 //   |ALL| matches all ciphers.
1401 //
1402 //   |kRSA|, |kDHE|, |kECDHE|, and |kPSK| match ciphers using plain RSA, DHE,
1403 //   ECDHE, and plain PSK key exchanges, respectively. Note that ECDHE_PSK is
1404 //   matched by |kECDHE| and not |kPSK|.
1405 //
1406 //   |aRSA|, |aECDSA|, and |aPSK| match ciphers authenticated by RSA, ECDSA, and
1407 //   a pre-shared key, respectively.
1408 //
1409 //   |RSA|, |DHE|, |ECDHE|, |PSK|, |ECDSA|, and |PSK| are aliases for the
1410 //   corresponding |k*| or |a*| cipher rule. |RSA| is an alias for |kRSA|, not
1411 //   |aRSA|.
1412 //
1413 //   |3DES|, |AES128|, |AES256|, |AES|, |AESGCM|, |CHACHA20| match ciphers
1414 //   whose bulk cipher use the corresponding encryption scheme. Note that
1415 //   |AES|, |AES128|, and |AES256| match both CBC and GCM ciphers.
1416 //
1417 //   |SHA1|, and its alias |SHA|, match legacy cipher suites using HMAC-SHA1.
1418 //
1419 // Although implemented, authentication-only ciphers match no rules and must be
1420 // explicitly selected by name.
1421 //
1422 // Deprecated cipher rules:
1423 //
1424 //   |kEDH|, |EDH|, |kEECDH|, and |EECDH| are legacy aliases for |kDHE|, |DHE|,
1425 //   |kECDHE|, and |ECDHE|, respectively.
1426 //
1427 //   |HIGH| is an alias for |ALL|.
1428 //
1429 //   |FIPS| is an alias for |HIGH|.
1430 //
1431 //   |SSLv3| and |TLSv1| match ciphers available in TLS 1.1 or earlier.
1432 //   |TLSv1_2| matches ciphers new in TLS 1.2. This is confusing and should not
1433 //   be used.
1434 //
1435 // Unknown rules are silently ignored by legacy APIs, and rejected by APIs with
1436 // "strict" in the name, which should be preferred. Cipher lists can be long
1437 // and it's easy to commit typos. Strict functions will also reject the use of
1438 // spaces, semi-colons and commas as alternative separators.
1439 //
1440 // The special |@STRENGTH| directive will sort all enabled ciphers by strength.
1441 //
1442 // The |DEFAULT| directive, when appearing at the front of the string, expands
1443 // to the default ordering of available ciphers.
1444 //
1445 // If configuring a server, one may also configure equal-preference groups to
1446 // partially respect the client's preferences when
1447 // |SSL_OP_CIPHER_SERVER_PREFERENCE| is enabled. Ciphers in an equal-preference
1448 // group have equal priority and use the client order. This may be used to
1449 // enforce that AEADs are preferred but select AES-GCM vs. ChaCha20-Poly1305
1450 // based on client preferences. An equal-preference is specified with square
1451 // brackets, combining multiple selectors separated by |. For example:
1452 //
1453 //   [TLS_ECDHE_ECDSA_WITH_CHACHA20_POLY1305_SHA256|TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256]
1454 //
1455 // Once an equal-preference group is used, future directives must be
1456 // opcode-less. Inside an equal-preference group, spaces are not allowed.
1457 //
1458 // TLS 1.3 ciphers do not participate in this mechanism and instead have a
1459 // built-in preference order. Functions to set cipher lists do not affect TLS
1460 // 1.3, and functions to query the cipher list do not include TLS 1.3
1461 // ciphers.
1462 
1463 // SSL_DEFAULT_CIPHER_LIST is the default cipher suite configuration. It is
1464 // substituted when a cipher string starts with 'DEFAULT'.
1465 #define SSL_DEFAULT_CIPHER_LIST "ALL"
1466 
1467 // SSL_CTX_set_strict_cipher_list configures the cipher list for |ctx|,
1468 // evaluating |str| as a cipher string and returning error if |str| contains
1469 // anything meaningless. It returns one on success and zero on failure.
1470 OPENSSL_EXPORT int SSL_CTX_set_strict_cipher_list(SSL_CTX *ctx,
1471                                                   const char *str);
1472 
1473 // SSL_CTX_set_cipher_list configures the cipher list for |ctx|, evaluating
1474 // |str| as a cipher string. It returns one on success and zero on failure.
1475 //
1476 // Prefer to use |SSL_CTX_set_strict_cipher_list|. This function tolerates
1477 // garbage inputs, unless an empty cipher list results.
1478 OPENSSL_EXPORT int SSL_CTX_set_cipher_list(SSL_CTX *ctx, const char *str);
1479 
1480 // SSL_set_strict_cipher_list configures the cipher list for |ssl|, evaluating
1481 // |str| as a cipher string and returning error if |str| contains anything
1482 // meaningless. It returns one on success and zero on failure.
1483 OPENSSL_EXPORT int SSL_set_strict_cipher_list(SSL *ssl, const char *str);
1484 
1485 // SSL_set_cipher_list configures the cipher list for |ssl|, evaluating |str| as
1486 // a cipher string. It returns one on success and zero on failure.
1487 //
1488 // Prefer to use |SSL_set_strict_cipher_list|. This function tolerates garbage
1489 // inputs, unless an empty cipher list results.
1490 OPENSSL_EXPORT int SSL_set_cipher_list(SSL *ssl, const char *str);
1491 
1492 // SSL_CTX_get_ciphers returns the cipher list for |ctx|, in order of
1493 // preference.
1494 OPENSSL_EXPORT STACK_OF(SSL_CIPHER) *SSL_CTX_get_ciphers(const SSL_CTX *ctx);
1495 
1496 // SSL_CTX_cipher_in_group returns one if the |i|th cipher (see
1497 // |SSL_CTX_get_ciphers|) is in the same equipreference group as the one
1498 // following it and zero otherwise.
1499 OPENSSL_EXPORT int SSL_CTX_cipher_in_group(const SSL_CTX *ctx, size_t i);
1500 
1501 // SSL_get_ciphers returns the cipher list for |ssl|, in order of preference.
1502 OPENSSL_EXPORT STACK_OF(SSL_CIPHER) *SSL_get_ciphers(const SSL *ssl);
1503 
1504 
1505 // Connection information.
1506 
1507 // SSL_is_init_finished returns one if |ssl| has completed its initial handshake
1508 // and has no pending handshake. It returns zero otherwise.
1509 OPENSSL_EXPORT int SSL_is_init_finished(const SSL *ssl);
1510 
1511 // SSL_in_init returns one if |ssl| has a pending handshake and zero
1512 // otherwise.
1513 OPENSSL_EXPORT int SSL_in_init(const SSL *ssl);
1514 
1515 // SSL_in_false_start returns one if |ssl| has a pending handshake that is in
1516 // False Start. |SSL_write| may be called at this point without waiting for the
1517 // peer, but |SSL_read| will complete the handshake before accepting application
1518 // data.
1519 //
1520 // See also |SSL_MODE_ENABLE_FALSE_START|.
1521 OPENSSL_EXPORT int SSL_in_false_start(const SSL *ssl);
1522 
1523 // SSL_get_peer_certificate returns the peer's leaf certificate or NULL if the
1524 // peer did not use certificates. The caller must call |X509_free| on the
1525 // result to release it.
1526 OPENSSL_EXPORT X509 *SSL_get_peer_certificate(const SSL *ssl);
1527 
1528 // SSL_get_peer_cert_chain returns the peer's certificate chain or NULL if
1529 // unavailable or the peer did not use certificates. This is the unverified list
1530 // of certificates as sent by the peer, not the final chain built during
1531 // verification. The caller does not take ownership of the result.
1532 //
1533 // WARNING: This function behaves differently between client and server. If
1534 // |ssl| is a server, the returned chain does not include the leaf certificate.
1535 // If a client, it does.
1536 OPENSSL_EXPORT STACK_OF(X509) *SSL_get_peer_cert_chain(const SSL *ssl);
1537 
1538 // SSL_get_peer_full_cert_chain returns the peer's certificate chain, or NULL if
1539 // unavailable or the peer did not use certificates. This is the unverified list
1540 // of certificates as sent by the peer, not the final chain built during
1541 // verification. The caller does not take ownership of the result.
1542 //
1543 // This is the same as |SSL_get_peer_cert_chain| except that this function
1544 // always returns the full chain, i.e. the first element of the return value
1545 // (if any) will be the leaf certificate. In constrast,
1546 // |SSL_get_peer_cert_chain| returns only the intermediate certificates if the
1547 // |ssl| is a server.
1548 OPENSSL_EXPORT STACK_OF(X509) *SSL_get_peer_full_cert_chain(const SSL *ssl);
1549 
1550 // SSL_get0_peer_certificates returns the peer's certificate chain, or NULL if
1551 // unavailable or the peer did not use certificates. This is the unverified list
1552 // of certificates as sent by the peer, not the final chain built during
1553 // verification. The caller does not take ownership of the result.
1554 //
1555 // This is the |CRYPTO_BUFFER| variant of |SSL_get_peer_full_cert_chain|.
1556 OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
1557     SSL_get0_peer_certificates(const SSL *ssl);
1558 
1559 // SSL_get0_signed_cert_timestamp_list sets |*out| and |*out_len| to point to
1560 // |*out_len| bytes of SCT information from the server. This is only valid if
1561 // |ssl| is a client. The SCT information is a SignedCertificateTimestampList
1562 // (including the two leading length bytes).
1563 // See https://tools.ietf.org/html/rfc6962#section-3.3
1564 // If no SCT was received then |*out_len| will be zero on return.
1565 //
1566 // WARNING: the returned data is not guaranteed to be well formed.
1567 OPENSSL_EXPORT void SSL_get0_signed_cert_timestamp_list(const SSL *ssl,
1568                                                         const uint8_t **out,
1569                                                         size_t *out_len);
1570 
1571 // SSL_get0_ocsp_response sets |*out| and |*out_len| to point to |*out_len|
1572 // bytes of an OCSP response from the server. This is the DER encoding of an
1573 // OCSPResponse type as defined in RFC 2560.
1574 //
1575 // WARNING: the returned data is not guaranteed to be well formed.
1576 OPENSSL_EXPORT void SSL_get0_ocsp_response(const SSL *ssl, const uint8_t **out,
1577                                            size_t *out_len);
1578 
1579 // SSL_get_tls_unique writes at most |max_out| bytes of the tls-unique value
1580 // for |ssl| to |out| and sets |*out_len| to the number of bytes written. It
1581 // returns one on success or zero on error. In general |max_out| should be at
1582 // least 12.
1583 //
1584 // This function will always fail if the initial handshake has not completed.
1585 // The tls-unique value will change after a renegotiation but, since
1586 // renegotiations can be initiated by the server at any point, the higher-level
1587 // protocol must either leave them disabled or define states in which the
1588 // tls-unique value can be read.
1589 //
1590 // The tls-unique value is defined by
1591 // https://tools.ietf.org/html/rfc5929#section-3.1. Due to a weakness in the
1592 // TLS protocol, tls-unique is broken for resumed connections unless the
1593 // Extended Master Secret extension is negotiated. Thus this function will
1594 // return zero if |ssl| performed session resumption unless EMS was used when
1595 // negotiating the original session.
1596 OPENSSL_EXPORT int SSL_get_tls_unique(const SSL *ssl, uint8_t *out,
1597                                       size_t *out_len, size_t max_out);
1598 
1599 // SSL_get_extms_support returns one if the Extended Master Secret extension or
1600 // TLS 1.3 was negotiated. Otherwise, it returns zero.
1601 OPENSSL_EXPORT int SSL_get_extms_support(const SSL *ssl);
1602 
1603 // SSL_get_current_cipher returns cipher suite used by |ssl|, or NULL if it has
1604 // not been negotiated yet.
1605 OPENSSL_EXPORT const SSL_CIPHER *SSL_get_current_cipher(const SSL *ssl);
1606 
1607 // SSL_session_reused returns one if |ssl| performed an abbreviated handshake
1608 // and zero otherwise.
1609 //
1610 // TODO(davidben): Hammer down the semantics of this API while a handshake,
1611 // initial or renego, is in progress.
1612 OPENSSL_EXPORT int SSL_session_reused(const SSL *ssl);
1613 
1614 // SSL_get_secure_renegotiation_support returns one if the peer supports secure
1615 // renegotiation (RFC 5746) or TLS 1.3. Otherwise, it returns zero.
1616 OPENSSL_EXPORT int SSL_get_secure_renegotiation_support(const SSL *ssl);
1617 
1618 // SSL_export_keying_material exports a value derived from the master secret, as
1619 // specified in RFC 5705. It writes |out_len| bytes to |out| given a label and
1620 // optional context. (Since a zero length context is allowed, the |use_context|
1621 // flag controls whether a context is included.)
1622 //
1623 // It returns one on success and zero otherwise.
1624 OPENSSL_EXPORT int SSL_export_keying_material(
1625     SSL *ssl, uint8_t *out, size_t out_len, const char *label, size_t label_len,
1626     const uint8_t *context, size_t context_len, int use_context);
1627 
1628 
1629 // Sessions.
1630 //
1631 // An |SSL_SESSION| represents an SSL session that may be resumed in an
1632 // abbreviated handshake. It is reference-counted and immutable. Once
1633 // established, an |SSL_SESSION| may be shared by multiple |SSL| objects on
1634 // different threads and must not be modified.
1635 
1636 DECLARE_PEM_rw(SSL_SESSION, SSL_SESSION)
1637 
1638 // SSL_SESSION_new returns a newly-allocated blank |SSL_SESSION| or NULL on
1639 // error. This may be useful when writing tests but should otherwise not be
1640 // used.
1641 OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_new(const SSL_CTX *ctx);
1642 
1643 // SSL_SESSION_up_ref increments the reference count of |session| and returns
1644 // one.
1645 OPENSSL_EXPORT int SSL_SESSION_up_ref(SSL_SESSION *session);
1646 
1647 // SSL_SESSION_free decrements the reference count of |session|. If it reaches
1648 // zero, all data referenced by |session| and |session| itself are released.
1649 OPENSSL_EXPORT void SSL_SESSION_free(SSL_SESSION *session);
1650 
1651 // SSL_SESSION_to_bytes serializes |in| into a newly allocated buffer and sets
1652 // |*out_data| to that buffer and |*out_len| to its length. The caller takes
1653 // ownership of the buffer and must call |OPENSSL_free| when done. It returns
1654 // one on success and zero on error.
1655 OPENSSL_EXPORT int SSL_SESSION_to_bytes(const SSL_SESSION *in,
1656                                         uint8_t **out_data, size_t *out_len);
1657 
1658 // SSL_SESSION_to_bytes_for_ticket serializes |in|, but excludes the session
1659 // identification information, namely the session ID and ticket.
1660 OPENSSL_EXPORT int SSL_SESSION_to_bytes_for_ticket(const SSL_SESSION *in,
1661                                                    uint8_t **out_data,
1662                                                    size_t *out_len);
1663 
1664 // SSL_SESSION_from_bytes parses |in_len| bytes from |in| as an SSL_SESSION. It
1665 // returns a newly-allocated |SSL_SESSION| on success or NULL on error.
1666 OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_from_bytes(
1667     const uint8_t *in, size_t in_len, const SSL_CTX *ctx);
1668 
1669 // SSL_SESSION_get_version returns a string describing the TLS or DTLS version
1670 // |session| was established at. For example, "TLSv1.2" or "DTLSv1".
1671 OPENSSL_EXPORT const char *SSL_SESSION_get_version(const SSL_SESSION *session);
1672 
1673 // SSL_SESSION_get_protocol_version returns the TLS or DTLS version |session|
1674 // was established at.
1675 OPENSSL_EXPORT uint16_t
1676 SSL_SESSION_get_protocol_version(const SSL_SESSION *session);
1677 
1678 // SSL_SESSION_set_protocol_version sets |session|'s TLS or DTLS version to
1679 // |version|. This may be useful when writing tests but should otherwise not be
1680 // used. It returns one on success and zero on error.
1681 OPENSSL_EXPORT int SSL_SESSION_set_protocol_version(SSL_SESSION *session,
1682                                                     uint16_t version);
1683 
1684 // SSL_MAX_SSL_SESSION_ID_LENGTH is the maximum length of an SSL session ID.
1685 #define SSL_MAX_SSL_SESSION_ID_LENGTH 32
1686 
1687 // SSL_SESSION_get_id returns a pointer to a buffer containing |session|'s
1688 // session ID and sets |*out_len| to its length.
1689 OPENSSL_EXPORT const uint8_t *SSL_SESSION_get_id(const SSL_SESSION *session,
1690                                                  unsigned *out_len);
1691 
1692 // SSL_SESSION_set1_id sets |session|'s session ID to |sid|, It returns one on
1693 // success and zero on error. This function may be useful in writing tests but
1694 // otherwise should not be used.
1695 OPENSSL_EXPORT int SSL_SESSION_set1_id(SSL_SESSION *session, const uint8_t *sid,
1696                                        size_t sid_len);
1697 
1698 // SSL_SESSION_get_time returns the time at which |session| was established in
1699 // seconds since the UNIX epoch.
1700 OPENSSL_EXPORT uint64_t SSL_SESSION_get_time(const SSL_SESSION *session);
1701 
1702 // SSL_SESSION_get_timeout returns the lifetime of |session| in seconds.
1703 OPENSSL_EXPORT uint32_t SSL_SESSION_get_timeout(const SSL_SESSION *session);
1704 
1705 // SSL_SESSION_get0_peer returns the peer leaf certificate stored in
1706 // |session|.
1707 //
1708 // TODO(davidben): This should return a const X509 *.
1709 OPENSSL_EXPORT X509 *SSL_SESSION_get0_peer(const SSL_SESSION *session);
1710 
1711 // SSL_SESSION_get0_peer_certificates returns the peer certificate chain stored
1712 // in |session|, or NULL if the peer did not use certificates. This is the
1713 // unverified list of certificates as sent by the peer, not the final chain
1714 // built during verification. The caller does not take ownership of the result.
1715 OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
1716     SSL_SESSION_get0_peer_certificates(const SSL_SESSION *session);
1717 
1718 // SSL_SESSION_get0_signed_cert_timestamp_list sets |*out| and |*out_len| to
1719 // point to |*out_len| bytes of SCT information stored in |session|. This is
1720 // only valid for client sessions. The SCT information is a
1721 // SignedCertificateTimestampList (including the two leading length bytes). See
1722 // https://tools.ietf.org/html/rfc6962#section-3.3 If no SCT was received then
1723 // |*out_len| will be zero on return.
1724 //
1725 // WARNING: the returned data is not guaranteed to be well formed.
1726 OPENSSL_EXPORT void SSL_SESSION_get0_signed_cert_timestamp_list(
1727     const SSL_SESSION *session, const uint8_t **out, size_t *out_len);
1728 
1729 // SSL_SESSION_get0_ocsp_response sets |*out| and |*out_len| to point to
1730 // |*out_len| bytes of an OCSP response from the server. This is the DER
1731 // encoding of an OCSPResponse type as defined in RFC 2560.
1732 //
1733 // WARNING: the returned data is not guaranteed to be well formed.
1734 OPENSSL_EXPORT void SSL_SESSION_get0_ocsp_response(const SSL_SESSION *session,
1735                                                    const uint8_t **out,
1736                                                    size_t *out_len);
1737 
1738 // SSL_MAX_MASTER_KEY_LENGTH is the maximum length of a master secret.
1739 #define SSL_MAX_MASTER_KEY_LENGTH 48
1740 
1741 // SSL_SESSION_get_master_key writes up to |max_out| bytes of |session|'s secret
1742 // to |out| and returns the number of bytes written. If |max_out| is zero, it
1743 // returns the size of the secret.
1744 OPENSSL_EXPORT size_t SSL_SESSION_get_master_key(const SSL_SESSION *session,
1745                                                  uint8_t *out, size_t max_out);
1746 
1747 // SSL_SESSION_set_time sets |session|'s creation time to |time| and returns
1748 // |time|. This function may be useful in writing tests but otherwise should not
1749 // be used.
1750 OPENSSL_EXPORT uint64_t SSL_SESSION_set_time(SSL_SESSION *session,
1751                                              uint64_t time);
1752 
1753 // SSL_SESSION_set_timeout sets |session|'s timeout to |timeout| and returns
1754 // one. This function may be useful in writing tests but otherwise should not
1755 // be used.
1756 OPENSSL_EXPORT uint32_t SSL_SESSION_set_timeout(SSL_SESSION *session,
1757                                                 uint32_t timeout);
1758 
1759 // SSL_SESSION_get0_id_context returns a pointer to a buffer containing
1760 // |session|'s session ID context (see |SSL_CTX_set_session_id_context|) and
1761 // sets |*out_len| to its length.
1762 OPENSSL_EXPORT const uint8_t *SSL_SESSION_get0_id_context(
1763     const SSL_SESSION *session, unsigned *out_len);
1764 
1765 // SSL_SESSION_set1_id_context sets |session|'s session ID context (see
1766 // |SSL_CTX_set_session_id_context|) to |sid_ctx|. It returns one on success and
1767 // zero on error. This function may be useful in writing tests but otherwise
1768 // should not be used.
1769 OPENSSL_EXPORT int SSL_SESSION_set1_id_context(SSL_SESSION *session,
1770                                                const uint8_t *sid_ctx,
1771                                                size_t sid_ctx_len);
1772 
1773 // SSL_SESSION_should_be_single_use returns one if |session| should be
1774 // single-use (TLS 1.3 and later) and zero otherwise.
1775 //
1776 // If this function returns one, clients retain multiple sessions and use each
1777 // only once. This prevents passive observers from correlating connections with
1778 // tickets. See RFC 8446, appendix C.4. If it returns zero, |session| cannot be
1779 // used without leaking a correlator.
1780 OPENSSL_EXPORT int SSL_SESSION_should_be_single_use(const SSL_SESSION *session);
1781 
1782 // SSL_SESSION_is_resumable returns one if |session| is resumable and zero
1783 // otherwise.
1784 OPENSSL_EXPORT int SSL_SESSION_is_resumable(const SSL_SESSION *session);
1785 
1786 // SSL_SESSION_has_ticket returns one if |session| has a ticket and zero
1787 // otherwise.
1788 OPENSSL_EXPORT int SSL_SESSION_has_ticket(const SSL_SESSION *session);
1789 
1790 // SSL_SESSION_get0_ticket sets |*out_ticket| and |*out_len| to |session|'s
1791 // ticket, or NULL and zero if it does not have one. |out_ticket| may be NULL
1792 // if only the ticket length is needed.
1793 OPENSSL_EXPORT void SSL_SESSION_get0_ticket(const SSL_SESSION *session,
1794                                             const uint8_t **out_ticket,
1795                                             size_t *out_len);
1796 
1797 // SSL_SESSION_set_ticket sets |session|'s ticket to |ticket|. It returns one on
1798 // success and zero on error. This function may be useful in writing tests but
1799 // otherwise should not be used.
1800 OPENSSL_EXPORT int SSL_SESSION_set_ticket(SSL_SESSION *session,
1801                                           const uint8_t *ticket,
1802                                           size_t ticket_len);
1803 
1804 // SSL_SESSION_get_ticket_lifetime_hint returns ticket lifetime hint of
1805 // |session| in seconds or zero if none was set.
1806 OPENSSL_EXPORT uint32_t
1807 SSL_SESSION_get_ticket_lifetime_hint(const SSL_SESSION *session);
1808 
1809 // SSL_SESSION_get0_cipher returns the cipher negotiated by the connection which
1810 // established |session|.
1811 //
1812 // Note that, in TLS 1.3, there is no guarantee that resumptions with |session|
1813 // will use that cipher. Prefer calling |SSL_get_current_cipher| on the |SSL|
1814 // instead.
1815 OPENSSL_EXPORT const SSL_CIPHER *SSL_SESSION_get0_cipher(
1816     const SSL_SESSION *session);
1817 
1818 // SSL_SESSION_has_peer_sha256 returns one if |session| has a SHA-256 hash of
1819 // the peer's certificate retained and zero if the peer did not present a
1820 // certificate or if this was not enabled when |session| was created. See also
1821 // |SSL_CTX_set_retain_only_sha256_of_client_certs|.
1822 OPENSSL_EXPORT int SSL_SESSION_has_peer_sha256(const SSL_SESSION *session);
1823 
1824 // SSL_SESSION_get0_peer_sha256 sets |*out_ptr| and |*out_len| to the SHA-256
1825 // hash of the peer certificate retained in |session|, or NULL and zero if it
1826 // does not have one. See also |SSL_CTX_set_retain_only_sha256_of_client_certs|.
1827 OPENSSL_EXPORT void SSL_SESSION_get0_peer_sha256(const SSL_SESSION *session,
1828                                                  const uint8_t **out_ptr,
1829                                                  size_t *out_len);
1830 
1831 
1832 // Session caching.
1833 //
1834 // Session caching allows connections to be established more efficiently based
1835 // on saved parameters from a previous connection, called a session (see
1836 // |SSL_SESSION|). The client offers a saved session, using an opaque identifier
1837 // from a previous connection. The server may accept the session, if it has the
1838 // parameters available. Otherwise, it will decline and continue with a full
1839 // handshake.
1840 //
1841 // This requires both the client and the server to retain session state. A
1842 // client does so with a stateful session cache. A server may do the same or, if
1843 // supported by both sides, statelessly using session tickets. For more
1844 // information on the latter, see the next section.
1845 //
1846 // For a server, the library implements a built-in internal session cache as an
1847 // in-memory hash table. Servers may also use |SSL_CTX_sess_set_get_cb| and
1848 // |SSL_CTX_sess_set_new_cb| to implement a custom external session cache. In
1849 // particular, this may be used to share a session cache between multiple
1850 // servers in a large deployment. An external cache may be used in addition to
1851 // or instead of the internal one. Use |SSL_CTX_set_session_cache_mode| to
1852 // toggle the internal cache.
1853 //
1854 // For a client, the only option is an external session cache. Clients may use
1855 // |SSL_CTX_sess_set_new_cb| to register a callback for when new sessions are
1856 // available. These may be cached and, in subsequent compatible connections,
1857 // configured with |SSL_set_session|.
1858 //
1859 // Note that offering or accepting a session short-circuits certificate
1860 // verification and most parameter negotiation. Resuming sessions across
1861 // different contexts may result in security failures and surprising
1862 // behavior. For a typical client, this means sessions for different hosts must
1863 // be cached under different keys. A client that connects to the same host with,
1864 // e.g., different cipher suite settings or client certificates should also use
1865 // separate session caches between those contexts. Servers should also partition
1866 // session caches between SNI hosts with |SSL_CTX_set_session_id_context|.
1867 //
1868 // Note also, in TLS 1.2 and earlier, offering sessions allows passive observers
1869 // to correlate different client connections. TLS 1.3 and later fix this,
1870 // provided clients use sessions at most once. Session caches are managed by the
1871 // caller in BoringSSL, so this must be implemented externally. See
1872 // |SSL_SESSION_should_be_single_use| for details.
1873 
1874 // SSL_SESS_CACHE_OFF disables all session caching.
1875 #define SSL_SESS_CACHE_OFF 0x0000
1876 
1877 // SSL_SESS_CACHE_CLIENT enables session caching for a client. The internal
1878 // cache is never used on a client, so this only enables the callbacks.
1879 #define SSL_SESS_CACHE_CLIENT 0x0001
1880 
1881 // SSL_SESS_CACHE_SERVER enables session caching for a server.
1882 #define SSL_SESS_CACHE_SERVER 0x0002
1883 
1884 // SSL_SESS_CACHE_BOTH enables session caching for both client and server.
1885 #define SSL_SESS_CACHE_BOTH (SSL_SESS_CACHE_CLIENT | SSL_SESS_CACHE_SERVER)
1886 
1887 // SSL_SESS_CACHE_NO_AUTO_CLEAR disables automatically calling
1888 // |SSL_CTX_flush_sessions| every 255 connections.
1889 #define SSL_SESS_CACHE_NO_AUTO_CLEAR 0x0080
1890 
1891 // SSL_SESS_CACHE_NO_INTERNAL_LOOKUP, on a server, disables looking up a session
1892 // from the internal session cache.
1893 #define SSL_SESS_CACHE_NO_INTERNAL_LOOKUP 0x0100
1894 
1895 // SSL_SESS_CACHE_NO_INTERNAL_STORE, on a server, disables storing sessions in
1896 // the internal session cache.
1897 #define SSL_SESS_CACHE_NO_INTERNAL_STORE 0x0200
1898 
1899 // SSL_SESS_CACHE_NO_INTERNAL, on a server, disables the internal session
1900 // cache.
1901 #define SSL_SESS_CACHE_NO_INTERNAL \
1902     (SSL_SESS_CACHE_NO_INTERNAL_LOOKUP | SSL_SESS_CACHE_NO_INTERNAL_STORE)
1903 
1904 // SSL_CTX_set_session_cache_mode sets the session cache mode bits for |ctx| to
1905 // |mode|. It returns the previous value.
1906 OPENSSL_EXPORT int SSL_CTX_set_session_cache_mode(SSL_CTX *ctx, int mode);
1907 
1908 // SSL_CTX_get_session_cache_mode returns the session cache mode bits for
1909 // |ctx|
1910 OPENSSL_EXPORT int SSL_CTX_get_session_cache_mode(const SSL_CTX *ctx);
1911 
1912 // SSL_set_session, for a client, configures |ssl| to offer to resume |session|
1913 // in the initial handshake and returns one. The caller retains ownership of
1914 // |session|. Note that configuring a session assumes the authentication in the
1915 // session is valid. For callers that wish to revalidate the session before
1916 // offering, see |SSL_SESSION_get0_peer_certificates|,
1917 // |SSL_SESSION_get0_signed_cert_timestamp_list|, and
1918 // |SSL_SESSION_get0_ocsp_response|.
1919 //
1920 // It is an error to call this function after the handshake has begun.
1921 OPENSSL_EXPORT int SSL_set_session(SSL *ssl, SSL_SESSION *session);
1922 
1923 // SSL_DEFAULT_SESSION_TIMEOUT is the default lifetime, in seconds, of a
1924 // session in TLS 1.2 or earlier. This is how long we are willing to use the
1925 // secret to encrypt traffic without fresh key material.
1926 #define SSL_DEFAULT_SESSION_TIMEOUT (2 * 60 * 60)
1927 
1928 // SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT is the default lifetime, in seconds, of a
1929 // session for TLS 1.3 psk_dhe_ke. This is how long we are willing to use the
1930 // secret as an authenticator.
1931 #define SSL_DEFAULT_SESSION_PSK_DHE_TIMEOUT (2 * 24 * 60 * 60)
1932 
1933 // SSL_DEFAULT_SESSION_AUTH_TIMEOUT is the default non-renewable lifetime, in
1934 // seconds, of a TLS 1.3 session. This is how long we are willing to trust the
1935 // signature in the initial handshake.
1936 #define SSL_DEFAULT_SESSION_AUTH_TIMEOUT (7 * 24 * 60 * 60)
1937 
1938 // SSL_CTX_set_timeout sets the lifetime, in seconds, of TLS 1.2 (or earlier)
1939 // sessions created in |ctx| to |timeout|.
1940 OPENSSL_EXPORT uint32_t SSL_CTX_set_timeout(SSL_CTX *ctx, uint32_t timeout);
1941 
1942 // SSL_CTX_set_session_psk_dhe_timeout sets the lifetime, in seconds, of TLS 1.3
1943 // sessions created in |ctx| to |timeout|.
1944 OPENSSL_EXPORT void SSL_CTX_set_session_psk_dhe_timeout(SSL_CTX *ctx,
1945                                                         uint32_t timeout);
1946 
1947 // SSL_CTX_get_timeout returns the lifetime, in seconds, of TLS 1.2 (or earlier)
1948 // sessions created in |ctx|.
1949 OPENSSL_EXPORT uint32_t SSL_CTX_get_timeout(const SSL_CTX *ctx);
1950 
1951 // SSL_MAX_SID_CTX_LENGTH is the maximum length of a session ID context.
1952 #define SSL_MAX_SID_CTX_LENGTH 32
1953 
1954 // SSL_CTX_set_session_id_context sets |ctx|'s session ID context to |sid_ctx|.
1955 // It returns one on success and zero on error. The session ID context is an
1956 // application-defined opaque byte string. A session will not be used in a
1957 // connection without a matching session ID context.
1958 //
1959 // For a server, if |SSL_VERIFY_PEER| is enabled, it is an error to not set a
1960 // session ID context.
1961 OPENSSL_EXPORT int SSL_CTX_set_session_id_context(SSL_CTX *ctx,
1962                                                   const uint8_t *sid_ctx,
1963                                                   size_t sid_ctx_len);
1964 
1965 // SSL_set_session_id_context sets |ssl|'s session ID context to |sid_ctx|. It
1966 // returns one on success and zero on error. See also
1967 // |SSL_CTX_set_session_id_context|.
1968 OPENSSL_EXPORT int SSL_set_session_id_context(SSL *ssl, const uint8_t *sid_ctx,
1969                                               size_t sid_ctx_len);
1970 
1971 // SSL_get0_session_id_context returns a pointer to |ssl|'s session ID context
1972 // and sets |*out_len| to its length.  It returns NULL on error.
1973 OPENSSL_EXPORT const uint8_t *SSL_get0_session_id_context(const SSL *ssl,
1974                                                           size_t *out_len);
1975 
1976 // SSL_SESSION_CACHE_MAX_SIZE_DEFAULT is the default maximum size of a session
1977 // cache.
1978 #define SSL_SESSION_CACHE_MAX_SIZE_DEFAULT (1024 * 20)
1979 
1980 // SSL_CTX_sess_set_cache_size sets the maximum size of |ctx|'s internal session
1981 // cache to |size|. It returns the previous value.
1982 OPENSSL_EXPORT unsigned long SSL_CTX_sess_set_cache_size(SSL_CTX *ctx,
1983                                                          unsigned long size);
1984 
1985 // SSL_CTX_sess_get_cache_size returns the maximum size of |ctx|'s internal
1986 // session cache.
1987 OPENSSL_EXPORT unsigned long SSL_CTX_sess_get_cache_size(const SSL_CTX *ctx);
1988 
1989 // SSL_CTX_sess_number returns the number of sessions in |ctx|'s internal
1990 // session cache.
1991 OPENSSL_EXPORT size_t SSL_CTX_sess_number(const SSL_CTX *ctx);
1992 
1993 // SSL_CTX_add_session inserts |session| into |ctx|'s internal session cache. It
1994 // returns one on success and zero on error or if |session| is already in the
1995 // cache. The caller retains its reference to |session|.
1996 OPENSSL_EXPORT int SSL_CTX_add_session(SSL_CTX *ctx, SSL_SESSION *session);
1997 
1998 // SSL_CTX_remove_session removes |session| from |ctx|'s internal session cache.
1999 // It returns one on success and zero if |session| was not in the cache.
2000 OPENSSL_EXPORT int SSL_CTX_remove_session(SSL_CTX *ctx, SSL_SESSION *session);
2001 
2002 // SSL_CTX_flush_sessions removes all sessions from |ctx| which have expired as
2003 // of time |time|. If |time| is zero, all sessions are removed.
2004 OPENSSL_EXPORT void SSL_CTX_flush_sessions(SSL_CTX *ctx, uint64_t time);
2005 
2006 // SSL_CTX_sess_set_new_cb sets the callback to be called when a new session is
2007 // established and ready to be cached. If the session cache is disabled (the
2008 // appropriate one of |SSL_SESS_CACHE_CLIENT| or |SSL_SESS_CACHE_SERVER| is
2009 // unset), the callback is not called.
2010 //
2011 // The callback is passed a reference to |session|. It returns one if it takes
2012 // ownership (and then calls |SSL_SESSION_free| when done) and zero otherwise. A
2013 // consumer which places |session| into an in-memory cache will likely return
2014 // one, with the cache calling |SSL_SESSION_free|. A consumer which serializes
2015 // |session| with |SSL_SESSION_to_bytes| may not need to retain |session| and
2016 // will likely return zero. Returning one is equivalent to calling
2017 // |SSL_SESSION_up_ref| and then returning zero.
2018 //
2019 // Note: For a client, the callback may be called on abbreviated handshakes if a
2020 // ticket is renewed. Further, it may not be called until some time after
2021 // |SSL_do_handshake| or |SSL_connect| completes if False Start is enabled. Thus
2022 // it's recommended to use this callback over calling |SSL_get_session| on
2023 // handshake completion.
2024 OPENSSL_EXPORT void SSL_CTX_sess_set_new_cb(
2025     SSL_CTX *ctx, int (*new_session_cb)(SSL *ssl, SSL_SESSION *session));
2026 
2027 // SSL_CTX_sess_get_new_cb returns the callback set by
2028 // |SSL_CTX_sess_set_new_cb|.
2029 OPENSSL_EXPORT int (*SSL_CTX_sess_get_new_cb(SSL_CTX *ctx))(
2030     SSL *ssl, SSL_SESSION *session);
2031 
2032 // SSL_CTX_sess_set_remove_cb sets a callback which is called when a session is
2033 // removed from the internal session cache.
2034 //
2035 // TODO(davidben): What is the point of this callback? It seems useless since it
2036 // only fires on sessions in the internal cache.
2037 OPENSSL_EXPORT void SSL_CTX_sess_set_remove_cb(
2038     SSL_CTX *ctx,
2039     void (*remove_session_cb)(SSL_CTX *ctx, SSL_SESSION *session));
2040 
2041 // SSL_CTX_sess_get_remove_cb returns the callback set by
2042 // |SSL_CTX_sess_set_remove_cb|.
2043 OPENSSL_EXPORT void (*SSL_CTX_sess_get_remove_cb(SSL_CTX *ctx))(
2044     SSL_CTX *ctx, SSL_SESSION *session);
2045 
2046 // SSL_CTX_sess_set_get_cb sets a callback to look up a session by ID for a
2047 // server. The callback is passed the session ID and should return a matching
2048 // |SSL_SESSION| or NULL if not found. It should set |*out_copy| to zero and
2049 // return a new reference to the session. This callback is not used for a
2050 // client.
2051 //
2052 // For historical reasons, if |*out_copy| is set to one (default), the SSL
2053 // library will take a new reference to the returned |SSL_SESSION|, expecting
2054 // the callback to return a non-owning pointer. This is not recommended. If
2055 // |ctx| and thus the callback is used on multiple threads, the session may be
2056 // removed and invalidated before the SSL library calls |SSL_SESSION_up_ref|,
2057 // whereas the callback may synchronize internally.
2058 //
2059 // To look up a session asynchronously, the callback may return
2060 // |SSL_magic_pending_session_ptr|. See the documentation for that function and
2061 // |SSL_ERROR_PENDING_SESSION|.
2062 //
2063 // If the internal session cache is enabled, the callback is only consulted if
2064 // the internal cache does not return a match.
2065 OPENSSL_EXPORT void SSL_CTX_sess_set_get_cb(
2066     SSL_CTX *ctx, SSL_SESSION *(*get_session_cb)(SSL *ssl, const uint8_t *id,
2067                                                  int id_len, int *out_copy));
2068 
2069 // SSL_CTX_sess_get_get_cb returns the callback set by
2070 // |SSL_CTX_sess_set_get_cb|.
2071 OPENSSL_EXPORT SSL_SESSION *(*SSL_CTX_sess_get_get_cb(SSL_CTX *ctx))(
2072     SSL *ssl, const uint8_t *id, int id_len, int *out_copy);
2073 
2074 // SSL_magic_pending_session_ptr returns a magic |SSL_SESSION|* which indicates
2075 // that the session isn't currently unavailable. |SSL_get_error| will then
2076 // return |SSL_ERROR_PENDING_SESSION| and the handshake can be retried later
2077 // when the lookup has completed.
2078 OPENSSL_EXPORT SSL_SESSION *SSL_magic_pending_session_ptr(void);
2079 
2080 
2081 // Session tickets.
2082 //
2083 // Session tickets, from RFC 5077, allow session resumption without server-side
2084 // state. The server maintains a secret ticket key and sends the client opaque
2085 // encrypted session parameters, called a ticket. When offering the session, the
2086 // client sends the ticket which the server decrypts to recover session state.
2087 // Session tickets are enabled by default but may be disabled with
2088 // |SSL_OP_NO_TICKET|.
2089 //
2090 // On the client, ticket-based sessions use the same APIs as ID-based tickets.
2091 // Callers do not need to handle them differently.
2092 //
2093 // On the server, tickets are encrypted and authenticated with a secret key.
2094 // By default, an |SSL_CTX| will manage session ticket encryption keys by
2095 // generating them internally and rotating every 48 hours. Tickets are minted
2096 // and processed transparently. The following functions may be used to configure
2097 // a persistent key or implement more custom behavior, including key rotation
2098 // and sharing keys between multiple servers in a large deployment. There are
2099 // three levels of customisation possible:
2100 //
2101 // 1) One can simply set the keys with |SSL_CTX_set_tlsext_ticket_keys|.
2102 // 2) One can configure an |EVP_CIPHER_CTX| and |HMAC_CTX| directly for
2103 //    encryption and authentication.
2104 // 3) One can configure an |SSL_TICKET_AEAD_METHOD| to have more control
2105 //    and the option of asynchronous decryption.
2106 //
2107 // An attacker that compromises a server's session ticket key can impersonate
2108 // the server and, prior to TLS 1.3, retroactively decrypt all application
2109 // traffic from sessions using that ticket key. Thus ticket keys must be
2110 // regularly rotated for forward secrecy. Note the default key is rotated
2111 // automatically once every 48 hours but manually configured keys are not.
2112 
2113 // SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL is the interval with which the
2114 // default session ticket encryption key is rotated, if in use. If any
2115 // non-default ticket encryption mechanism is configured, automatic rotation is
2116 // disabled.
2117 #define SSL_DEFAULT_TICKET_KEY_ROTATION_INTERVAL (2 * 24 * 60 * 60)
2118 
2119 // SSL_CTX_get_tlsext_ticket_keys writes |ctx|'s session ticket key material to
2120 // |len| bytes of |out|. It returns one on success and zero if |len| is not
2121 // 48. If |out| is NULL, it returns 48 instead.
2122 OPENSSL_EXPORT int SSL_CTX_get_tlsext_ticket_keys(SSL_CTX *ctx, void *out,
2123                                                   size_t len);
2124 
2125 // SSL_CTX_set_tlsext_ticket_keys sets |ctx|'s session ticket key material to
2126 // |len| bytes of |in|. It returns one on success and zero if |len| is not
2127 // 48. If |in| is NULL, it returns 48 instead.
2128 OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_keys(SSL_CTX *ctx, const void *in,
2129                                                   size_t len);
2130 
2131 // SSL_TICKET_KEY_NAME_LEN is the length of the key name prefix of a session
2132 // ticket.
2133 #define SSL_TICKET_KEY_NAME_LEN 16
2134 
2135 // SSL_CTX_set_tlsext_ticket_key_cb sets the ticket callback to |callback| and
2136 // returns one. |callback| will be called when encrypting a new ticket and when
2137 // decrypting a ticket from the client.
2138 //
2139 // In both modes, |ctx| and |hmac_ctx| will already have been initialized with
2140 // |EVP_CIPHER_CTX_init| and |HMAC_CTX_init|, respectively. |callback|
2141 // configures |hmac_ctx| with an HMAC digest and key, and configures |ctx|
2142 // for encryption or decryption, based on the mode.
2143 //
2144 // When encrypting a new ticket, |encrypt| will be one. It writes a public
2145 // 16-byte key name to |key_name| and a fresh IV to |iv|. The output IV length
2146 // must match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
2147 // |callback| returns 1 on success and -1 on error.
2148 //
2149 // When decrypting a ticket, |encrypt| will be zero. |key_name| will point to a
2150 // 16-byte key name and |iv| points to an IV. The length of the IV consumed must
2151 // match |EVP_CIPHER_CTX_iv_length| of the cipher selected. In this mode,
2152 // |callback| returns -1 to abort the handshake, 0 if decrypting the ticket
2153 // failed, and 1 or 2 on success. If it returns 2, the ticket will be renewed.
2154 // This may be used to re-key the ticket.
2155 //
2156 // WARNING: |callback| wildly breaks the usual return value convention and is
2157 // called in two different modes.
2158 OPENSSL_EXPORT int SSL_CTX_set_tlsext_ticket_key_cb(
2159     SSL_CTX *ctx, int (*callback)(SSL *ssl, uint8_t *key_name, uint8_t *iv,
2160                                   EVP_CIPHER_CTX *ctx, HMAC_CTX *hmac_ctx,
2161                                   int encrypt));
2162 
2163 // ssl_ticket_aead_result_t enumerates the possible results from decrypting a
2164 // ticket with an |SSL_TICKET_AEAD_METHOD|.
2165 enum ssl_ticket_aead_result_t BORINGSSL_ENUM_INT {
2166   // ssl_ticket_aead_success indicates that the ticket was successfully
2167   // decrypted.
2168   ssl_ticket_aead_success,
2169   // ssl_ticket_aead_retry indicates that the operation could not be
2170   // immediately completed and must be reattempted, via |open|, at a later
2171   // point.
2172   ssl_ticket_aead_retry,
2173   // ssl_ticket_aead_ignore_ticket indicates that the ticket should be ignored
2174   // (i.e. is corrupt or otherwise undecryptable).
2175   ssl_ticket_aead_ignore_ticket,
2176   // ssl_ticket_aead_error indicates that a fatal error occured and the
2177   // handshake should be terminated.
2178   ssl_ticket_aead_error,
2179 };
2180 
2181 // ssl_ticket_aead_method_st (aka |SSL_TICKET_AEAD_METHOD|) contains methods
2182 // for encrypting and decrypting session tickets.
2183 struct ssl_ticket_aead_method_st {
2184   // max_overhead returns the maximum number of bytes of overhead that |seal|
2185   // may add.
2186   size_t (*max_overhead)(SSL *ssl);
2187 
2188   // seal encrypts and authenticates |in_len| bytes from |in|, writes, at most,
2189   // |max_out_len| bytes to |out|, and puts the number of bytes written in
2190   // |*out_len|. The |in| and |out| buffers may be equal but will not otherwise
2191   // alias. It returns one on success or zero on error.
2192   int (*seal)(SSL *ssl, uint8_t *out, size_t *out_len, size_t max_out_len,
2193               const uint8_t *in, size_t in_len);
2194 
2195   // open authenticates and decrypts |in_len| bytes from |in|, writes, at most,
2196   // |max_out_len| bytes of plaintext to |out|, and puts the number of bytes
2197   // written in |*out_len|. The |in| and |out| buffers may be equal but will
2198   // not otherwise alias. See |ssl_ticket_aead_result_t| for details of the
2199   // return values. In the case that a retry is indicated, the caller should
2200   // arrange for the high-level operation on |ssl| to be retried when the
2201   // operation is completed, which will result in another call to |open|.
2202   enum ssl_ticket_aead_result_t (*open)(SSL *ssl, uint8_t *out, size_t *out_len,
2203                                         size_t max_out_len, const uint8_t *in,
2204                                         size_t in_len);
2205 };
2206 
2207 // SSL_CTX_set_ticket_aead_method configures a custom ticket AEAD method table
2208 // on |ctx|. |aead_method| must remain valid for the lifetime of |ctx|.
2209 OPENSSL_EXPORT void SSL_CTX_set_ticket_aead_method(
2210     SSL_CTX *ctx, const SSL_TICKET_AEAD_METHOD *aead_method);
2211 
2212 // SSL_process_tls13_new_session_ticket processes an unencrypted TLS 1.3
2213 // NewSessionTicket message from |buf| and returns a resumable |SSL_SESSION|,
2214 // or NULL on error. The caller takes ownership of the returned session and
2215 // must call |SSL_SESSION_free| to free it.
2216 //
2217 // |buf| contains |buf_len| bytes that represents a complete NewSessionTicket
2218 // message including its header, i.e., one byte for the type (0x04) and three
2219 // bytes for the length. |buf| must contain only one such message.
2220 //
2221 // This function may be used to process NewSessionTicket messages in TLS 1.3
2222 // clients that are handling the record layer externally.
2223 OPENSSL_EXPORT SSL_SESSION *SSL_process_tls13_new_session_ticket(
2224     SSL *ssl, const uint8_t *buf, size_t buf_len);
2225 
2226 
2227 // Elliptic curve Diffie-Hellman.
2228 //
2229 // Cipher suites using an ECDHE key exchange perform Diffie-Hellman over an
2230 // elliptic curve negotiated by both endpoints. See RFC 4492. Only named curves
2231 // are supported. ECDHE is always enabled, but the curve preferences may be
2232 // configured with these functions.
2233 //
2234 // Note that TLS 1.3 renames these from curves to groups. For consistency, we
2235 // currently use the TLS 1.2 name in the API.
2236 
2237 // SSL_CTX_set1_curves sets the preferred curves for |ctx| to be |curves|. Each
2238 // element of |curves| should be a curve nid. It returns one on success and
2239 // zero on failure.
2240 //
2241 // Note that this API uses nid values from nid.h and not the |SSL_CURVE_*|
2242 // values defined below.
2243 OPENSSL_EXPORT int SSL_CTX_set1_curves(SSL_CTX *ctx, const int *curves,
2244                                        size_t curves_len);
2245 
2246 // SSL_set1_curves sets the preferred curves for |ssl| to be |curves|. Each
2247 // element of |curves| should be a curve nid. It returns one on success and
2248 // zero on failure.
2249 //
2250 // Note that this API uses nid values from nid.h and not the |SSL_CURVE_*|
2251 // values defined below.
2252 OPENSSL_EXPORT int SSL_set1_curves(SSL *ssl, const int *curves,
2253                                    size_t curves_len);
2254 
2255 // SSL_CTX_set1_curves_list sets the preferred curves for |ctx| to be the
2256 // colon-separated list |curves|. Each element of |curves| should be a curve
2257 // name (e.g. P-256, X25519, ...). It returns one on success and zero on
2258 // failure.
2259 OPENSSL_EXPORT int SSL_CTX_set1_curves_list(SSL_CTX *ctx, const char *curves);
2260 
2261 // SSL_set1_curves_list sets the preferred curves for |ssl| to be the
2262 // colon-separated list |curves|. Each element of |curves| should be a curve
2263 // name (e.g. P-256, X25519, ...). It returns one on success and zero on
2264 // failure.
2265 OPENSSL_EXPORT int SSL_set1_curves_list(SSL *ssl, const char *curves);
2266 
2267 // SSL_CURVE_* define TLS curve IDs.
2268 #define SSL_CURVE_SECP224R1 21
2269 #define SSL_CURVE_SECP256R1 23
2270 #define SSL_CURVE_SECP384R1 24
2271 #define SSL_CURVE_SECP521R1 25
2272 #define SSL_CURVE_X25519 29
2273 #define SSL_CURVE_CECPQ2 16696
2274 
2275 // SSL_get_curve_id returns the ID of the curve used by |ssl|'s most recently
2276 // completed handshake or 0 if not applicable.
2277 //
2278 // TODO(davidben): This API currently does not work correctly if there is a
2279 // renegotiation in progress. Fix this.
2280 OPENSSL_EXPORT uint16_t SSL_get_curve_id(const SSL *ssl);
2281 
2282 // SSL_get_curve_name returns a human-readable name for the curve specified by
2283 // the given TLS curve id, or NULL if the curve is unknown.
2284 OPENSSL_EXPORT const char *SSL_get_curve_name(uint16_t curve_id);
2285 
2286 
2287 // Certificate verification.
2288 //
2289 // SSL may authenticate either endpoint with an X.509 certificate. Typically
2290 // this is used to authenticate the server to the client. These functions
2291 // configure certificate verification.
2292 //
2293 // WARNING: By default, certificate verification errors on a client are not
2294 // fatal. See |SSL_VERIFY_NONE| This may be configured with
2295 // |SSL_CTX_set_verify|.
2296 //
2297 // By default clients are anonymous but a server may request a certificate from
2298 // the client by setting |SSL_VERIFY_PEER|.
2299 //
2300 // Many of these functions use OpenSSL's legacy X.509 stack which is
2301 // underdocumented and deprecated, but the replacement isn't ready yet. For
2302 // now, consumers may use the existing stack or bypass it by performing
2303 // certificate verification externally. This may be done with
2304 // |SSL_CTX_set_cert_verify_callback| or by extracting the chain with
2305 // |SSL_get_peer_cert_chain| after the handshake. In the future, functions will
2306 // be added to use the SSL stack without dependency on any part of the legacy
2307 // X.509 and ASN.1 stack.
2308 //
2309 // To augment certificate verification, a client may also enable OCSP stapling
2310 // (RFC 6066) and Certificate Transparency (RFC 6962) extensions.
2311 
2312 // SSL_VERIFY_NONE, on a client, verifies the server certificate but does not
2313 // make errors fatal. The result may be checked with |SSL_get_verify_result|. On
2314 // a server it does not request a client certificate. This is the default.
2315 #define SSL_VERIFY_NONE 0x00
2316 
2317 // SSL_VERIFY_PEER, on a client, makes server certificate errors fatal. On a
2318 // server it requests a client certificate and makes errors fatal. However,
2319 // anonymous clients are still allowed. See
2320 // |SSL_VERIFY_FAIL_IF_NO_PEER_CERT|.
2321 #define SSL_VERIFY_PEER 0x01
2322 
2323 // SSL_VERIFY_FAIL_IF_NO_PEER_CERT configures a server to reject connections if
2324 // the client declines to send a certificate. This flag must be used together
2325 // with |SSL_VERIFY_PEER|, otherwise it won't work.
2326 #define SSL_VERIFY_FAIL_IF_NO_PEER_CERT 0x02
2327 
2328 // SSL_VERIFY_PEER_IF_NO_OBC configures a server to request a client certificate
2329 // if and only if Channel ID is not negotiated.
2330 #define SSL_VERIFY_PEER_IF_NO_OBC 0x04
2331 
2332 // SSL_CTX_set_verify configures certificate verification behavior. |mode| is
2333 // one of the |SSL_VERIFY_*| values defined above. |callback|, if not NULL, is
2334 // used to customize certificate verification. See the behavior of
2335 // |X509_STORE_CTX_set_verify_cb|.
2336 //
2337 // The callback may use |SSL_get_ex_data_X509_STORE_CTX_idx| with
2338 // |X509_STORE_CTX_get_ex_data| to look up the |SSL| from |store_ctx|.
2339 OPENSSL_EXPORT void SSL_CTX_set_verify(
2340     SSL_CTX *ctx, int mode, int (*callback)(int ok, X509_STORE_CTX *store_ctx));
2341 
2342 // SSL_set_verify configures certificate verification behavior. |mode| is one of
2343 // the |SSL_VERIFY_*| values defined above. |callback|, if not NULL, is used to
2344 // customize certificate verification. See the behavior of
2345 // |X509_STORE_CTX_set_verify_cb|.
2346 //
2347 // The callback may use |SSL_get_ex_data_X509_STORE_CTX_idx| with
2348 // |X509_STORE_CTX_get_ex_data| to look up the |SSL| from |store_ctx|.
2349 OPENSSL_EXPORT void SSL_set_verify(SSL *ssl, int mode,
2350                                    int (*callback)(int ok,
2351                                                    X509_STORE_CTX *store_ctx));
2352 
2353 enum ssl_verify_result_t BORINGSSL_ENUM_INT {
2354   ssl_verify_ok,
2355   ssl_verify_invalid,
2356   ssl_verify_retry,
2357 };
2358 
2359 // SSL_CTX_set_custom_verify configures certificate verification. |mode| is one
2360 // of the |SSL_VERIFY_*| values defined above. |callback| performs the
2361 // certificate verification.
2362 //
2363 // The callback may call |SSL_get0_peer_certificates| for the certificate chain
2364 // to validate. The callback should return |ssl_verify_ok| if the certificate is
2365 // valid. If the certificate is invalid, the callback should return
2366 // |ssl_verify_invalid| and optionally set |*out_alert| to an alert to send to
2367 // the peer. Some useful alerts include |SSL_AD_CERTIFICATE_EXPIRED|,
2368 // |SSL_AD_CERTIFICATE_REVOKED|, |SSL_AD_UNKNOWN_CA|, |SSL_AD_BAD_CERTIFICATE|,
2369 // |SSL_AD_CERTIFICATE_UNKNOWN|, and |SSL_AD_INTERNAL_ERROR|. See RFC 5246
2370 // section 7.2.2 for their precise meanings. If unspecified,
2371 // |SSL_AD_CERTIFICATE_UNKNOWN| will be sent by default.
2372 //
2373 // To verify a certificate asynchronously, the callback may return
2374 // |ssl_verify_retry|. The handshake will then pause with |SSL_get_error|
2375 // returning |SSL_ERROR_WANT_CERTIFICATE_VERIFY|.
2376 OPENSSL_EXPORT void SSL_CTX_set_custom_verify(
2377     SSL_CTX *ctx, int mode,
2378     enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert));
2379 
2380 // SSL_set_custom_verify behaves like |SSL_CTX_set_custom_verify| but configures
2381 // an individual |SSL|.
2382 OPENSSL_EXPORT void SSL_set_custom_verify(
2383     SSL *ssl, int mode,
2384     enum ssl_verify_result_t (*callback)(SSL *ssl, uint8_t *out_alert));
2385 
2386 // SSL_CTX_get_verify_mode returns |ctx|'s verify mode, set by
2387 // |SSL_CTX_set_verify|.
2388 OPENSSL_EXPORT int SSL_CTX_get_verify_mode(const SSL_CTX *ctx);
2389 
2390 // SSL_get_verify_mode returns |ssl|'s verify mode, set by |SSL_CTX_set_verify|
2391 // or |SSL_set_verify|.  It returns -1 on error.
2392 OPENSSL_EXPORT int SSL_get_verify_mode(const SSL *ssl);
2393 
2394 // SSL_CTX_get_verify_callback returns the callback set by
2395 // |SSL_CTX_set_verify|.
2396 OPENSSL_EXPORT int (*SSL_CTX_get_verify_callback(const SSL_CTX *ctx))(
2397     int ok, X509_STORE_CTX *store_ctx);
2398 
2399 // SSL_get_verify_callback returns the callback set by |SSL_CTX_set_verify| or
2400 // |SSL_set_verify|.
2401 OPENSSL_EXPORT int (*SSL_get_verify_callback(const SSL *ssl))(
2402     int ok, X509_STORE_CTX *store_ctx);
2403 
2404 // SSL_CTX_set_verify_depth sets the maximum depth of a certificate chain
2405 // accepted in verification. This number does not include the leaf, so a depth
2406 // of 1 allows the leaf and one CA certificate.
2407 OPENSSL_EXPORT void SSL_CTX_set_verify_depth(SSL_CTX *ctx, int depth);
2408 
2409 // SSL_set_verify_depth sets the maximum depth of a certificate chain accepted
2410 // in verification. This number does not include the leaf, so a depth of 1
2411 // allows the leaf and one CA certificate.
2412 OPENSSL_EXPORT void SSL_set_verify_depth(SSL *ssl, int depth);
2413 
2414 // SSL_CTX_get_verify_depth returns the maximum depth of a certificate accepted
2415 // in verification.
2416 OPENSSL_EXPORT int SSL_CTX_get_verify_depth(const SSL_CTX *ctx);
2417 
2418 // SSL_get_verify_depth returns the maximum depth of a certificate accepted in
2419 // verification.
2420 OPENSSL_EXPORT int SSL_get_verify_depth(const SSL *ssl);
2421 
2422 // SSL_CTX_set1_param sets verification parameters from |param|. It returns one
2423 // on success and zero on failure. The caller retains ownership of |param|.
2424 OPENSSL_EXPORT int SSL_CTX_set1_param(SSL_CTX *ctx,
2425                                       const X509_VERIFY_PARAM *param);
2426 
2427 // SSL_set1_param sets verification parameters from |param|. It returns one on
2428 // success and zero on failure. The caller retains ownership of |param|.
2429 OPENSSL_EXPORT int SSL_set1_param(SSL *ssl,
2430                                   const X509_VERIFY_PARAM *param);
2431 
2432 // SSL_CTX_get0_param returns |ctx|'s |X509_VERIFY_PARAM| for certificate
2433 // verification. The caller must not release the returned pointer but may call
2434 // functions on it to configure it.
2435 OPENSSL_EXPORT X509_VERIFY_PARAM *SSL_CTX_get0_param(SSL_CTX *ctx);
2436 
2437 // SSL_get0_param returns |ssl|'s |X509_VERIFY_PARAM| for certificate
2438 // verification. The caller must not release the returned pointer but may call
2439 // functions on it to configure it.
2440 OPENSSL_EXPORT X509_VERIFY_PARAM *SSL_get0_param(SSL *ssl);
2441 
2442 // SSL_CTX_set_purpose sets |ctx|'s |X509_VERIFY_PARAM|'s 'purpose' parameter to
2443 // |purpose|. It returns one on success and zero on error.
2444 OPENSSL_EXPORT int SSL_CTX_set_purpose(SSL_CTX *ctx, int purpose);
2445 
2446 // SSL_set_purpose sets |ssl|'s |X509_VERIFY_PARAM|'s 'purpose' parameter to
2447 // |purpose|. It returns one on success and zero on error.
2448 OPENSSL_EXPORT int SSL_set_purpose(SSL *ssl, int purpose);
2449 
2450 // SSL_CTX_set_trust sets |ctx|'s |X509_VERIFY_PARAM|'s 'trust' parameter to
2451 // |trust|. It returns one on success and zero on error.
2452 OPENSSL_EXPORT int SSL_CTX_set_trust(SSL_CTX *ctx, int trust);
2453 
2454 // SSL_set_trust sets |ssl|'s |X509_VERIFY_PARAM|'s 'trust' parameter to
2455 // |trust|. It returns one on success and zero on error.
2456 OPENSSL_EXPORT int SSL_set_trust(SSL *ssl, int trust);
2457 
2458 // SSL_CTX_set_cert_store sets |ctx|'s certificate store to |store|. It takes
2459 // ownership of |store|. The store is used for certificate verification.
2460 //
2461 // The store is also used for the auto-chaining feature, but this is deprecated.
2462 // See also |SSL_MODE_NO_AUTO_CHAIN|.
2463 OPENSSL_EXPORT void SSL_CTX_set_cert_store(SSL_CTX *ctx, X509_STORE *store);
2464 
2465 // SSL_CTX_get_cert_store returns |ctx|'s certificate store.
2466 OPENSSL_EXPORT X509_STORE *SSL_CTX_get_cert_store(const SSL_CTX *ctx);
2467 
2468 // SSL_CTX_set_default_verify_paths loads the OpenSSL system-default trust
2469 // anchors into |ctx|'s store. It returns one on success and zero on failure.
2470 OPENSSL_EXPORT int SSL_CTX_set_default_verify_paths(SSL_CTX *ctx);
2471 
2472 // SSL_CTX_load_verify_locations loads trust anchors into |ctx|'s store from
2473 // |ca_file| and |ca_dir|, either of which may be NULL. If |ca_file| is passed,
2474 // it is opened and PEM-encoded CA certificates are read. If |ca_dir| is passed,
2475 // it is treated as a directory in OpenSSL's hashed directory format. It returns
2476 // one on success and zero on failure.
2477 //
2478 // See
2479 // https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_load_verify_locations.html
2480 // for documentation on the directory format.
2481 OPENSSL_EXPORT int SSL_CTX_load_verify_locations(SSL_CTX *ctx,
2482                                                  const char *ca_file,
2483                                                  const char *ca_dir);
2484 
2485 // SSL_get_verify_result returns the result of certificate verification. It is
2486 // either |X509_V_OK| or a |X509_V_ERR_*| value.
2487 OPENSSL_EXPORT long SSL_get_verify_result(const SSL *ssl);
2488 
2489 // SSL_alert_from_verify_result returns the SSL alert code, such as
2490 // |SSL_AD_CERTIFICATE_EXPIRED|, that corresponds to an |X509_V_ERR_*| value.
2491 // The return value is always an alert, even when |result| is |X509_V_OK|.
2492 OPENSSL_EXPORT int SSL_alert_from_verify_result(long result);
2493 
2494 // SSL_get_ex_data_X509_STORE_CTX_idx returns the ex_data index used to look up
2495 // the |SSL| associated with an |X509_STORE_CTX| in the verify callback.
2496 OPENSSL_EXPORT int SSL_get_ex_data_X509_STORE_CTX_idx(void);
2497 
2498 // SSL_CTX_set_cert_verify_callback sets a custom callback to be called on
2499 // certificate verification rather than |X509_verify_cert|. |store_ctx| contains
2500 // the verification parameters. The callback should return one on success and
2501 // zero on fatal error. It may use |X509_STORE_CTX_set_error| to set a
2502 // verification result.
2503 //
2504 // The callback may use |SSL_get_ex_data_X509_STORE_CTX_idx| to recover the
2505 // |SSL| object from |store_ctx|.
2506 OPENSSL_EXPORT void SSL_CTX_set_cert_verify_callback(
2507     SSL_CTX *ctx, int (*callback)(X509_STORE_CTX *store_ctx, void *arg),
2508     void *arg);
2509 
2510 // SSL_enable_signed_cert_timestamps causes |ssl| (which must be the client end
2511 // of a connection) to request SCTs from the server. See
2512 // https://tools.ietf.org/html/rfc6962.
2513 //
2514 // Call |SSL_get0_signed_cert_timestamp_list| to recover the SCT after the
2515 // handshake.
2516 OPENSSL_EXPORT void SSL_enable_signed_cert_timestamps(SSL *ssl);
2517 
2518 // SSL_CTX_enable_signed_cert_timestamps enables SCT requests on all client SSL
2519 // objects created from |ctx|.
2520 //
2521 // Call |SSL_get0_signed_cert_timestamp_list| to recover the SCT after the
2522 // handshake.
2523 OPENSSL_EXPORT void SSL_CTX_enable_signed_cert_timestamps(SSL_CTX *ctx);
2524 
2525 // SSL_enable_ocsp_stapling causes |ssl| (which must be the client end of a
2526 // connection) to request a stapled OCSP response from the server.
2527 //
2528 // Call |SSL_get0_ocsp_response| to recover the OCSP response after the
2529 // handshake.
2530 OPENSSL_EXPORT void SSL_enable_ocsp_stapling(SSL *ssl);
2531 
2532 // SSL_CTX_enable_ocsp_stapling enables OCSP stapling on all client SSL objects
2533 // created from |ctx|.
2534 //
2535 // Call |SSL_get0_ocsp_response| to recover the OCSP response after the
2536 // handshake.
2537 OPENSSL_EXPORT void SSL_CTX_enable_ocsp_stapling(SSL_CTX *ctx);
2538 
2539 // SSL_CTX_set0_verify_cert_store sets an |X509_STORE| that will be used
2540 // exclusively for certificate verification and returns one. Ownership of
2541 // |store| is transferred to the |SSL_CTX|.
2542 OPENSSL_EXPORT int SSL_CTX_set0_verify_cert_store(SSL_CTX *ctx,
2543                                                   X509_STORE *store);
2544 
2545 // SSL_CTX_set1_verify_cert_store sets an |X509_STORE| that will be used
2546 // exclusively for certificate verification and returns one. An additional
2547 // reference to |store| will be taken.
2548 OPENSSL_EXPORT int SSL_CTX_set1_verify_cert_store(SSL_CTX *ctx,
2549                                                   X509_STORE *store);
2550 
2551 // SSL_set0_verify_cert_store sets an |X509_STORE| that will be used
2552 // exclusively for certificate verification and returns one. Ownership of
2553 // |store| is transferred to the |SSL|.
2554 OPENSSL_EXPORT int SSL_set0_verify_cert_store(SSL *ssl, X509_STORE *store);
2555 
2556 // SSL_set1_verify_cert_store sets an |X509_STORE| that will be used
2557 // exclusively for certificate verification and returns one. An additional
2558 // reference to |store| will be taken.
2559 OPENSSL_EXPORT int SSL_set1_verify_cert_store(SSL *ssl, X509_STORE *store);
2560 
2561 // SSL_CTX_set_verify_algorithm_prefs configures |ctx| to use |prefs| as the
2562 // preference list when verifying signatures from the peer's long-term key. It
2563 // returns one on zero on error. |prefs| should not include the internal-only
2564 // value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
2565 OPENSSL_EXPORT int SSL_CTX_set_verify_algorithm_prefs(SSL_CTX *ctx,
2566                                                       const uint16_t *prefs,
2567                                                       size_t num_prefs);
2568 
2569 // SSL_set_verify_algorithm_prefs configures |ssl| to use |prefs| as the
2570 // preference list when verifying signatures from the peer's long-term key. It
2571 // returns one on zero on error. |prefs| should not include the internal-only
2572 // value |SSL_SIGN_RSA_PKCS1_MD5_SHA1|.
2573 OPENSSL_EXPORT int SSL_set_verify_algorithm_prefs(SSL *ssl,
2574                                                   const uint16_t *prefs,
2575                                                   size_t num_prefs);
2576 
2577 
2578 // Client certificate CA list.
2579 //
2580 // When requesting a client certificate, a server may advertise a list of
2581 // certificate authorities which are accepted. These functions may be used to
2582 // configure this list.
2583 
2584 // SSL_set_client_CA_list sets |ssl|'s client certificate CA list to
2585 // |name_list|. It takes ownership of |name_list|.
2586 OPENSSL_EXPORT void SSL_set_client_CA_list(SSL *ssl,
2587                                            STACK_OF(X509_NAME) *name_list);
2588 
2589 // SSL_CTX_set_client_CA_list sets |ctx|'s client certificate CA list to
2590 // |name_list|. It takes ownership of |name_list|.
2591 OPENSSL_EXPORT void SSL_CTX_set_client_CA_list(SSL_CTX *ctx,
2592                                                STACK_OF(X509_NAME) *name_list);
2593 
2594 // SSL_set0_client_CAs sets |ssl|'s client certificate CA list to |name_list|,
2595 // which should contain DER-encoded distinguished names (RFC 5280). It takes
2596 // ownership of |name_list|.
2597 OPENSSL_EXPORT void SSL_set0_client_CAs(SSL *ssl,
2598                                         STACK_OF(CRYPTO_BUFFER) *name_list);
2599 
2600 // SSL_CTX_set0_client_CAs sets |ctx|'s client certificate CA list to
2601 // |name_list|, which should contain DER-encoded distinguished names (RFC 5280).
2602 // It takes ownership of |name_list|.
2603 OPENSSL_EXPORT void SSL_CTX_set0_client_CAs(SSL_CTX *ctx,
2604                                             STACK_OF(CRYPTO_BUFFER) *name_list);
2605 
2606 // SSL_get_client_CA_list returns |ssl|'s client certificate CA list. If |ssl|
2607 // has not been configured as a client, this is the list configured by
2608 // |SSL_CTX_set_client_CA_list|.
2609 //
2610 // If configured as a client, it returns the client certificate CA list sent by
2611 // the server. In this mode, the behavior is undefined except during the
2612 // callbacks set by |SSL_CTX_set_cert_cb| and |SSL_CTX_set_client_cert_cb| or
2613 // when the handshake is paused because of them.
2614 OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_get_client_CA_list(const SSL *ssl);
2615 
2616 // SSL_get0_server_requested_CAs returns the CAs sent by a server to guide a
2617 // client in certificate selection. They are a series of DER-encoded X.509
2618 // names. This function may only be called during a callback set by
2619 // |SSL_CTX_set_cert_cb| or when the handshake is paused because of it.
2620 //
2621 // The returned stack is owned by |ssl|, as are its contents. It should not be
2622 // used past the point where the handshake is restarted after the callback.
2623 OPENSSL_EXPORT const STACK_OF(CRYPTO_BUFFER) *
2624     SSL_get0_server_requested_CAs(const SSL *ssl);
2625 
2626 // SSL_CTX_get_client_CA_list returns |ctx|'s client certificate CA list.
2627 OPENSSL_EXPORT STACK_OF(X509_NAME) *
2628     SSL_CTX_get_client_CA_list(const SSL_CTX *ctx);
2629 
2630 // SSL_add_client_CA appends |x509|'s subject to the client certificate CA list.
2631 // It returns one on success or zero on error. The caller retains ownership of
2632 // |x509|.
2633 OPENSSL_EXPORT int SSL_add_client_CA(SSL *ssl, X509 *x509);
2634 
2635 // SSL_CTX_add_client_CA appends |x509|'s subject to the client certificate CA
2636 // list. It returns one on success or zero on error. The caller retains
2637 // ownership of |x509|.
2638 OPENSSL_EXPORT int SSL_CTX_add_client_CA(SSL_CTX *ctx, X509 *x509);
2639 
2640 // SSL_load_client_CA_file opens |file| and reads PEM-encoded certificates from
2641 // it. It returns a newly-allocated stack of the certificate subjects or NULL
2642 // on error.
2643 OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_load_client_CA_file(const char *file);
2644 
2645 // SSL_dup_CA_list makes a deep copy of |list|. It returns the new list on
2646 // success or NULL on allocation error.
2647 OPENSSL_EXPORT STACK_OF(X509_NAME) *SSL_dup_CA_list(STACK_OF(X509_NAME) *list);
2648 
2649 // SSL_add_file_cert_subjects_to_stack behaves like |SSL_load_client_CA_file|
2650 // but appends the result to |out|. It returns one on success or zero on
2651 // error.
2652 OPENSSL_EXPORT int SSL_add_file_cert_subjects_to_stack(STACK_OF(X509_NAME) *out,
2653                                                        const char *file);
2654 
2655 
2656 // Server name indication.
2657 //
2658 // The server_name extension (RFC 3546) allows the client to advertise the name
2659 // of the server it is connecting to. This is used in virtual hosting
2660 // deployments to select one of a several certificates on a single IP. Only the
2661 // host_name name type is supported.
2662 
2663 #define TLSEXT_NAMETYPE_host_name 0
2664 
2665 // SSL_set_tlsext_host_name, for a client, configures |ssl| to advertise |name|
2666 // in the server_name extension. It returns one on success and zero on error.
2667 OPENSSL_EXPORT int SSL_set_tlsext_host_name(SSL *ssl, const char *name);
2668 
2669 // SSL_get_servername, for a server, returns the hostname supplied by the
2670 // client or NULL if there was none. The |type| argument must be
2671 // |TLSEXT_NAMETYPE_host_name|.
2672 OPENSSL_EXPORT const char *SSL_get_servername(const SSL *ssl, const int type);
2673 
2674 // SSL_get_servername_type, for a server, returns |TLSEXT_NAMETYPE_host_name|
2675 // if the client sent a hostname and -1 otherwise.
2676 OPENSSL_EXPORT int SSL_get_servername_type(const SSL *ssl);
2677 
2678 // SSL_CTX_set_tlsext_servername_callback configures |callback| to be called on
2679 // the server after ClientHello extensions have been parsed and returns one.
2680 // The callback may use |SSL_get_servername| to examine the server_name
2681 // extension and returns a |SSL_TLSEXT_ERR_*| value. The value of |arg| may be
2682 // set by calling |SSL_CTX_set_tlsext_servername_arg|.
2683 //
2684 // If the callback returns |SSL_TLSEXT_ERR_NOACK|, the server_name extension is
2685 // not acknowledged in the ServerHello. If the return value is
2686 // |SSL_TLSEXT_ERR_ALERT_FATAL|, then |*out_alert| is the alert to send,
2687 // defaulting to |SSL_AD_UNRECOGNIZED_NAME|. |SSL_TLSEXT_ERR_ALERT_WARNING| is
2688 // ignored and treated as |SSL_TLSEXT_ERR_OK|.
2689 OPENSSL_EXPORT int SSL_CTX_set_tlsext_servername_callback(
2690     SSL_CTX *ctx, int (*callback)(SSL *ssl, int *out_alert, void *arg));
2691 
2692 // SSL_CTX_set_tlsext_servername_arg sets the argument to the servername
2693 // callback and returns one. See |SSL_CTX_set_tlsext_servername_callback|.
2694 OPENSSL_EXPORT int SSL_CTX_set_tlsext_servername_arg(SSL_CTX *ctx, void *arg);
2695 
2696 // SSL_TLSEXT_ERR_* are values returned by some extension-related callbacks.
2697 #define SSL_TLSEXT_ERR_OK 0
2698 #define SSL_TLSEXT_ERR_ALERT_WARNING 1
2699 #define SSL_TLSEXT_ERR_ALERT_FATAL 2
2700 #define SSL_TLSEXT_ERR_NOACK 3
2701 
2702 // SSL_set_SSL_CTX changes |ssl|'s |SSL_CTX|. |ssl| will use the
2703 // certificate-related settings from |ctx|, and |SSL_get_SSL_CTX| will report
2704 // |ctx|. This function may be used during the callbacks registered by
2705 // |SSL_CTX_set_select_certificate_cb|,
2706 // |SSL_CTX_set_tlsext_servername_callback|, and |SSL_CTX_set_cert_cb| or when
2707 // the handshake is paused from them. It is typically used to switch
2708 // certificates based on SNI.
2709 //
2710 // Note the session cache and related settings will continue to use the initial
2711 // |SSL_CTX|. Callers should use |SSL_CTX_set_session_id_context| to partition
2712 // the session cache between different domains.
2713 //
2714 // TODO(davidben): Should other settings change after this call?
2715 OPENSSL_EXPORT SSL_CTX *SSL_set_SSL_CTX(SSL *ssl, SSL_CTX *ctx);
2716 
2717 
2718 // Application-layer protocol negotiation.
2719 //
2720 // The ALPN extension (RFC 7301) allows negotiating different application-layer
2721 // protocols over a single port. This is used, for example, to negotiate
2722 // HTTP/2.
2723 
2724 // SSL_CTX_set_alpn_protos sets the client ALPN protocol list on |ctx| to
2725 // |protos|. |protos| must be in wire-format (i.e. a series of non-empty, 8-bit
2726 // length-prefixed strings). It returns zero on success and one on failure.
2727 // Configuring this list enables ALPN on a client.
2728 //
2729 // WARNING: this function is dangerous because it breaks the usual return value
2730 // convention.
2731 OPENSSL_EXPORT int SSL_CTX_set_alpn_protos(SSL_CTX *ctx, const uint8_t *protos,
2732                                            unsigned protos_len);
2733 
2734 // SSL_set_alpn_protos sets the client ALPN protocol list on |ssl| to |protos|.
2735 // |protos| must be in wire-format (i.e. a series of non-empty, 8-bit
2736 // length-prefixed strings). It returns zero on success and one on failure.
2737 // Configuring this list enables ALPN on a client.
2738 //
2739 // WARNING: this function is dangerous because it breaks the usual return value
2740 // convention.
2741 OPENSSL_EXPORT int SSL_set_alpn_protos(SSL *ssl, const uint8_t *protos,
2742                                        unsigned protos_len);
2743 
2744 // SSL_CTX_set_alpn_select_cb sets a callback function on |ctx| that is called
2745 // during ClientHello processing in order to select an ALPN protocol from the
2746 // client's list of offered protocols. Configuring this callback enables ALPN on
2747 // a server.
2748 //
2749 // The callback is passed a wire-format (i.e. a series of non-empty, 8-bit
2750 // length-prefixed strings) ALPN protocol list in |in|. It should set |*out| and
2751 // |*out_len| to the selected protocol and return |SSL_TLSEXT_ERR_OK| on
2752 // success. It does not pass ownership of the buffer. Otherwise, it should
2753 // return |SSL_TLSEXT_ERR_NOACK|. Other |SSL_TLSEXT_ERR_*| values are
2754 // unimplemented and will be treated as |SSL_TLSEXT_ERR_NOACK|.
2755 //
2756 // The cipher suite is selected before negotiating ALPN. The callback may use
2757 // |SSL_get_pending_cipher| to query the cipher suite.
2758 OPENSSL_EXPORT void SSL_CTX_set_alpn_select_cb(
2759     SSL_CTX *ctx, int (*cb)(SSL *ssl, const uint8_t **out, uint8_t *out_len,
2760                             const uint8_t *in, unsigned in_len, void *arg),
2761     void *arg);
2762 
2763 // SSL_get0_alpn_selected gets the selected ALPN protocol (if any) from |ssl|.
2764 // On return it sets |*out_data| to point to |*out_len| bytes of protocol name
2765 // (not including the leading length-prefix byte). If the server didn't respond
2766 // with a negotiated protocol then |*out_len| will be zero.
2767 OPENSSL_EXPORT void SSL_get0_alpn_selected(const SSL *ssl,
2768                                            const uint8_t **out_data,
2769                                            unsigned *out_len);
2770 
2771 // SSL_CTX_set_allow_unknown_alpn_protos configures client connections on |ctx|
2772 // to allow unknown ALPN protocols from the server. Otherwise, by default, the
2773 // client will require that the protocol be advertised in
2774 // |SSL_CTX_set_alpn_protos|.
2775 OPENSSL_EXPORT void SSL_CTX_set_allow_unknown_alpn_protos(SSL_CTX *ctx,
2776                                                           int enabled);
2777 
2778 
2779 // Application-layer protocol settings
2780 //
2781 // The ALPS extension (draft-vvv-tls-alps) allows exchanging application-layer
2782 // settings in the TLS handshake for applications negotiated with ALPN. Note
2783 // that, when ALPS is negotiated, the client and server each advertise their own
2784 // settings, so there are functions to both configure setting to send and query
2785 // received settings.
2786 
2787 // SSL_add_application_settings configures |ssl| to enable ALPS with ALPN
2788 // protocol |proto|, sending an ALPS value of |settings|. It returns one on
2789 // success and zero on error. If |proto| is negotiated via ALPN and the peer
2790 // supports ALPS, |settings| will be sent to the peer. The peer's ALPS value can
2791 // be retrieved with |SSL_get0_peer_application_settings|.
2792 //
2793 // On the client, this function should be called before the handshake, once for
2794 // each supported ALPN protocol which uses ALPS. |proto| must be included in the
2795 // client's ALPN configuration (see |SSL_CTX_set_alpn_protos| and
2796 // |SSL_set_alpn_protos|). On the server, ALPS can be preconfigured for each
2797 // protocol as in the client, or configuration can be deferred to the ALPN
2798 // callback (see |SSL_CTX_set_alpn_select_cb|), in which case only the selected
2799 // protocol needs to be configured.
2800 //
2801 // ALPS can be independently configured from 0-RTT, however changes in protocol
2802 // settings will fallback to 1-RTT to negotiate the new value, so it is
2803 // recommended for |settings| to be relatively stable.
2804 OPENSSL_EXPORT int SSL_add_application_settings(SSL *ssl, const uint8_t *proto,
2805                                                 size_t proto_len,
2806                                                 const uint8_t *settings,
2807                                                 size_t settings_len);
2808 
2809 // SSL_get0_peer_application_settings sets |*out_data| and |*out_len| to a
2810 // buffer containing the peer's ALPS value, or the empty string if ALPS was not
2811 // negotiated. Note an empty string could also indicate the peer sent an empty
2812 // settings value. Use |SSL_has_application_settings| to check if ALPS was
2813 // negotiated. The output buffer is owned by |ssl| and is valid until the next
2814 // time |ssl| is modified.
2815 OPENSSL_EXPORT void SSL_get0_peer_application_settings(const SSL *ssl,
2816                                                        const uint8_t **out_data,
2817                                                        size_t *out_len);
2818 
2819 // SSL_has_application_settings returns one if ALPS was negotiated on this
2820 // connection and zero otherwise.
2821 OPENSSL_EXPORT int SSL_has_application_settings(const SSL *ssl);
2822 
2823 
2824 // Certificate compression.
2825 //
2826 // Certificates in TLS 1.3 can be compressed (RFC 8879). BoringSSL supports this
2827 // as both a client and a server, but does not link against any specific
2828 // compression libraries in order to keep dependencies to a minimum. Instead,
2829 // hooks for compression and decompression can be installed in an |SSL_CTX| to
2830 // enable support.
2831 
2832 // ssl_cert_compression_func_t is a pointer to a function that performs
2833 // compression. It must write the compressed representation of |in| to |out|,
2834 // returning one on success and zero on error. The results of compressing
2835 // certificates are not cached internally. Implementations may wish to implement
2836 // their own cache if they expect it to be useful given the certificates that
2837 // they serve.
2838 typedef int (*ssl_cert_compression_func_t)(SSL *ssl, CBB *out,
2839                                            const uint8_t *in, size_t in_len);
2840 
2841 // ssl_cert_decompression_func_t is a pointer to a function that performs
2842 // decompression. The compressed data from the peer is passed as |in| and the
2843 // decompressed result must be exactly |uncompressed_len| bytes long. It returns
2844 // one on success, in which case |*out| must be set to the result of
2845 // decompressing |in|, or zero on error. Setting |*out| transfers ownership,
2846 // i.e. |CRYPTO_BUFFER_free| will be called on |*out| at some point in the
2847 // future. The results of decompressions are not cached internally.
2848 // Implementations may wish to implement their own cache if they expect it to be
2849 // useful.
2850 typedef int (*ssl_cert_decompression_func_t)(SSL *ssl, CRYPTO_BUFFER **out,
2851                                              size_t uncompressed_len,
2852                                              const uint8_t *in, size_t in_len);
2853 
2854 // SSL_CTX_add_cert_compression_alg registers a certificate compression
2855 // algorithm on |ctx| with ID |alg_id|. (The value of |alg_id| should be an IANA
2856 // assigned value and each can only be registered once.)
2857 //
2858 // One of the function pointers may be NULL to avoid having to implement both
2859 // sides of a compression algorithm if you're only going to use it in one
2860 // direction. In this case, the unimplemented direction acts like it was never
2861 // configured.
2862 //
2863 // For a server, algorithms are registered in preference order with the most
2864 // preferable first. It returns one on success or zero on error.
2865 OPENSSL_EXPORT int SSL_CTX_add_cert_compression_alg(
2866     SSL_CTX *ctx, uint16_t alg_id, ssl_cert_compression_func_t compress,
2867     ssl_cert_decompression_func_t decompress);
2868 
2869 
2870 // Next protocol negotiation.
2871 //
2872 // The NPN extension (draft-agl-tls-nextprotoneg-03) is the predecessor to ALPN
2873 // and deprecated in favor of it.
2874 
2875 // SSL_CTX_set_next_protos_advertised_cb sets a callback that is called when a
2876 // TLS server needs a list of supported protocols for Next Protocol
2877 // Negotiation. The returned list must be in wire format. The list is returned
2878 // by setting |*out| to point to it and |*out_len| to its length. This memory
2879 // will not be modified, but one should assume that |ssl| keeps a reference to
2880 // it.
2881 //
2882 // The callback should return |SSL_TLSEXT_ERR_OK| if it wishes to advertise.
2883 // Otherwise, no such extension will be included in the ServerHello.
2884 OPENSSL_EXPORT void SSL_CTX_set_next_protos_advertised_cb(
2885     SSL_CTX *ctx,
2886     int (*cb)(SSL *ssl, const uint8_t **out, unsigned *out_len, void *arg),
2887     void *arg);
2888 
2889 // SSL_CTX_set_next_proto_select_cb sets a callback that is called when a client
2890 // needs to select a protocol from the server's provided list. |*out| must be
2891 // set to point to the selected protocol (which may be within |in|). The length
2892 // of the protocol name must be written into |*out_len|. The server's advertised
2893 // protocols are provided in |in| and |in_len|. The callback can assume that
2894 // |in| is syntactically valid.
2895 //
2896 // The client must select a protocol. It is fatal to the connection if this
2897 // callback returns a value other than |SSL_TLSEXT_ERR_OK|.
2898 //
2899 // Configuring this callback enables NPN on a client.
2900 OPENSSL_EXPORT void SSL_CTX_set_next_proto_select_cb(
2901     SSL_CTX *ctx, int (*cb)(SSL *ssl, uint8_t **out, uint8_t *out_len,
2902                             const uint8_t *in, unsigned in_len, void *arg),
2903     void *arg);
2904 
2905 // SSL_get0_next_proto_negotiated sets |*out_data| and |*out_len| to point to
2906 // the client's requested protocol for this connection. If the client didn't
2907 // request any protocol, then |*out_data| is set to NULL.
2908 //
2909 // Note that the client can request any protocol it chooses. The value returned
2910 // from this function need not be a member of the list of supported protocols
2911 // provided by the server.
2912 OPENSSL_EXPORT void SSL_get0_next_proto_negotiated(const SSL *ssl,
2913                                                    const uint8_t **out_data,
2914                                                    unsigned *out_len);
2915 
2916 // SSL_select_next_proto implements the standard protocol selection. It is
2917 // expected that this function is called from the callback set by
2918 // |SSL_CTX_set_next_proto_select_cb|.
2919 //
2920 // |peer| and |supported| must be vectors of 8-bit, length-prefixed byte strings
2921 // containing the peer and locally-configured protocols, respectively. The
2922 // length byte itself is not included in the length. A byte string of length 0
2923 // is invalid. No byte string may be truncated. |supported| is assumed to be
2924 // non-empty.
2925 //
2926 // This function finds the first protocol in |peer| which is also in
2927 // |supported|. If one was found, it sets |*out| and |*out_len| to point to it
2928 // and returns |OPENSSL_NPN_NEGOTIATED|. Otherwise, it returns
2929 // |OPENSSL_NPN_NO_OVERLAP| and sets |*out| and |*out_len| to the first
2930 // supported protocol.
2931 OPENSSL_EXPORT int SSL_select_next_proto(uint8_t **out, uint8_t *out_len,
2932                                          const uint8_t *peer, unsigned peer_len,
2933                                          const uint8_t *supported,
2934                                          unsigned supported_len);
2935 
2936 #define OPENSSL_NPN_UNSUPPORTED 0
2937 #define OPENSSL_NPN_NEGOTIATED 1
2938 #define OPENSSL_NPN_NO_OVERLAP 2
2939 
2940 
2941 // Channel ID.
2942 //
2943 // See draft-balfanz-tls-channelid-01.
2944 
2945 // SSL_CTX_set_tls_channel_id_enabled configures whether connections associated
2946 // with |ctx| should enable Channel ID.
2947 OPENSSL_EXPORT void SSL_CTX_set_tls_channel_id_enabled(SSL_CTX *ctx,
2948                                                        int enabled);
2949 
2950 // SSL_set_tls_channel_id_enabled configures whether |ssl| should enable Channel
2951 // ID.
2952 OPENSSL_EXPORT void SSL_set_tls_channel_id_enabled(SSL *ssl, int enabled);
2953 
2954 // SSL_CTX_set1_tls_channel_id configures a TLS client to send a TLS Channel ID
2955 // to compatible servers. |private_key| must be a P-256 EC key. It returns one
2956 // on success and zero on error.
2957 OPENSSL_EXPORT int SSL_CTX_set1_tls_channel_id(SSL_CTX *ctx,
2958                                                EVP_PKEY *private_key);
2959 
2960 // SSL_set1_tls_channel_id configures a TLS client to send a TLS Channel ID to
2961 // compatible servers. |private_key| must be a P-256 EC key. It returns one on
2962 // success and zero on error.
2963 OPENSSL_EXPORT int SSL_set1_tls_channel_id(SSL *ssl, EVP_PKEY *private_key);
2964 
2965 // SSL_get_tls_channel_id gets the client's TLS Channel ID from a server |SSL*|
2966 // and copies up to the first |max_out| bytes into |out|. The Channel ID
2967 // consists of the client's P-256 public key as an (x,y) pair where each is a
2968 // 32-byte, big-endian field element. It returns 0 if the client didn't offer a
2969 // Channel ID and the length of the complete Channel ID otherwise.
2970 OPENSSL_EXPORT size_t SSL_get_tls_channel_id(SSL *ssl, uint8_t *out,
2971                                              size_t max_out);
2972 
2973 // SSL_CTX_set_channel_id_cb sets a callback to be called when a TLS Channel ID
2974 // is requested. The callback may set |*out_pkey| to a key, passing a reference
2975 // to the caller. If none is returned, the handshake will pause and
2976 // |SSL_get_error| will return |SSL_ERROR_WANT_CHANNEL_ID_LOOKUP|.
2977 //
2978 // See also |SSL_ERROR_WANT_CHANNEL_ID_LOOKUP|.
2979 OPENSSL_EXPORT void SSL_CTX_set_channel_id_cb(
2980     SSL_CTX *ctx, void (*channel_id_cb)(SSL *ssl, EVP_PKEY **out_pkey));
2981 
2982 // SSL_CTX_get_channel_id_cb returns the callback set by
2983 // |SSL_CTX_set_channel_id_cb|.
2984 OPENSSL_EXPORT void (*SSL_CTX_get_channel_id_cb(SSL_CTX *ctx))(
2985     SSL *ssl, EVP_PKEY **out_pkey);
2986 
2987 
2988 // Token Binding.
2989 //
2990 // See draft-ietf-tokbind-protocol-16.
2991 
2992 // SSL_set_token_binding_params sets |params| as the Token Binding Key
2993 // parameters (section 3 of draft-ietf-tokbind-protocol-16) to negotiate on the
2994 // connection. If this function is not called, or if |len| is 0, then this
2995 // endpoint will not attempt to negotiate Token Binding. |params| are provided
2996 // in preference order, with the more preferred parameters at the beginning of
2997 // the list. This function returns 1 on success and 0 on failure.
2998 OPENSSL_EXPORT int SSL_set_token_binding_params(SSL *ssl, const uint8_t *params,
2999                                                 size_t len);
3000 
3001 // SSL_is_token_binding_negotiated returns 1 if Token Binding was negotiated
3002 // on this connection and 0 otherwise. On a server, it is possible for this
3003 // function to return 1 when the client's view of the connection is that Token
3004 // Binding was not negotiated. This occurs when the server indicates a version
3005 // of Token Binding less than the client's minimum version.
3006 OPENSSL_EXPORT int SSL_is_token_binding_negotiated(const SSL *ssl);
3007 
3008 // SSL_get_negotiated_token_binding_param returns the TokenBindingKeyParameters
3009 // enum value that was negotiated. It is only valid to call this function if
3010 // SSL_is_token_binding_negotiated returned 1, otherwise this function returns
3011 // an undefined value.
3012 OPENSSL_EXPORT uint8_t SSL_get_negotiated_token_binding_param(const SSL *ssl);
3013 
3014 
3015 // DTLS-SRTP.
3016 //
3017 // See RFC 5764.
3018 
3019 // srtp_protection_profile_st (aka |SRTP_PROTECTION_PROFILE|) is an SRTP
3020 // profile for use with the use_srtp extension.
3021 struct srtp_protection_profile_st {
3022   const char *name;
3023   unsigned long id;
3024 } /* SRTP_PROTECTION_PROFILE */;
3025 
3026 DEFINE_CONST_STACK_OF(SRTP_PROTECTION_PROFILE)
3027 
3028 // SRTP_* define constants for SRTP profiles.
3029 #define SRTP_AES128_CM_SHA1_80 0x0001
3030 #define SRTP_AES128_CM_SHA1_32 0x0002
3031 #define SRTP_AES128_F8_SHA1_80 0x0003
3032 #define SRTP_AES128_F8_SHA1_32 0x0004
3033 #define SRTP_NULL_SHA1_80      0x0005
3034 #define SRTP_NULL_SHA1_32      0x0006
3035 #define SRTP_AEAD_AES_128_GCM  0x0007
3036 #define SRTP_AEAD_AES_256_GCM  0x0008
3037 
3038 // SSL_CTX_set_srtp_profiles enables SRTP for all SSL objects created from
3039 // |ctx|. |profile| contains a colon-separated list of profile names. It returns
3040 // one on success and zero on failure.
3041 OPENSSL_EXPORT int SSL_CTX_set_srtp_profiles(SSL_CTX *ctx,
3042                                              const char *profiles);
3043 
3044 // SSL_set_srtp_profiles enables SRTP for |ssl|.  |profile| contains a
3045 // colon-separated list of profile names. It returns one on success and zero on
3046 // failure.
3047 OPENSSL_EXPORT int SSL_set_srtp_profiles(SSL *ssl, const char *profiles);
3048 
3049 // SSL_get_srtp_profiles returns the SRTP profiles supported by |ssl|.
3050 OPENSSL_EXPORT STACK_OF(SRTP_PROTECTION_PROFILE) *SSL_get_srtp_profiles(
3051     SSL *ssl);
3052 
3053 // SSL_get_selected_srtp_profile returns the selected SRTP profile, or NULL if
3054 // SRTP was not negotiated.
3055 OPENSSL_EXPORT const SRTP_PROTECTION_PROFILE *SSL_get_selected_srtp_profile(
3056     SSL *ssl);
3057 
3058 
3059 // Pre-shared keys.
3060 //
3061 // Connections may be configured with PSK (Pre-Shared Key) cipher suites. These
3062 // authenticate using out-of-band pre-shared keys rather than certificates. See
3063 // RFC 4279.
3064 //
3065 // This implementation uses NUL-terminated C strings for identities and identity
3066 // hints, so values with a NUL character are not supported. (RFC 4279 does not
3067 // specify the format of an identity.)
3068 
3069 // PSK_MAX_IDENTITY_LEN is the maximum supported length of a PSK identity,
3070 // excluding the NUL terminator.
3071 #define PSK_MAX_IDENTITY_LEN 128
3072 
3073 // PSK_MAX_PSK_LEN is the maximum supported length of a pre-shared key.
3074 #define PSK_MAX_PSK_LEN 256
3075 
3076 // SSL_CTX_set_psk_client_callback sets the callback to be called when PSK is
3077 // negotiated on the client. This callback must be set to enable PSK cipher
3078 // suites on the client.
3079 //
3080 // The callback is passed the identity hint in |hint| or NULL if none was
3081 // provided. It should select a PSK identity and write the identity and the
3082 // corresponding PSK to |identity| and |psk|, respectively. The identity is
3083 // written as a NUL-terminated C string of length (excluding the NUL terminator)
3084 // at most |max_identity_len|. The PSK's length must be at most |max_psk_len|.
3085 // The callback returns the length of the PSK or 0 if no suitable identity was
3086 // found.
3087 OPENSSL_EXPORT void SSL_CTX_set_psk_client_callback(
3088     SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
3089                                  unsigned max_identity_len, uint8_t *psk,
3090                                  unsigned max_psk_len));
3091 
3092 // SSL_set_psk_client_callback sets the callback to be called when PSK is
3093 // negotiated on the client. This callback must be set to enable PSK cipher
3094 // suites on the client. See also |SSL_CTX_set_psk_client_callback|.
3095 OPENSSL_EXPORT void SSL_set_psk_client_callback(
3096     SSL *ssl, unsigned (*cb)(SSL *ssl, const char *hint, char *identity,
3097                              unsigned max_identity_len, uint8_t *psk,
3098                              unsigned max_psk_len));
3099 
3100 // SSL_CTX_set_psk_server_callback sets the callback to be called when PSK is
3101 // negotiated on the server. This callback must be set to enable PSK cipher
3102 // suites on the server.
3103 //
3104 // The callback is passed the identity in |identity|. It should write a PSK of
3105 // length at most |max_psk_len| to |psk| and return the number of bytes written
3106 // or zero if the PSK identity is unknown.
3107 OPENSSL_EXPORT void SSL_CTX_set_psk_server_callback(
3108     SSL_CTX *ctx, unsigned (*cb)(SSL *ssl, const char *identity, uint8_t *psk,
3109                                  unsigned max_psk_len));
3110 
3111 // SSL_set_psk_server_callback sets the callback to be called when PSK is
3112 // negotiated on the server. This callback must be set to enable PSK cipher
3113 // suites on the server. See also |SSL_CTX_set_psk_server_callback|.
3114 OPENSSL_EXPORT void SSL_set_psk_server_callback(
3115     SSL *ssl, unsigned (*cb)(SSL *ssl, const char *identity, uint8_t *psk,
3116                              unsigned max_psk_len));
3117 
3118 // SSL_CTX_use_psk_identity_hint configures server connections to advertise an
3119 // identity hint of |identity_hint|. It returns one on success and zero on
3120 // error.
3121 OPENSSL_EXPORT int SSL_CTX_use_psk_identity_hint(SSL_CTX *ctx,
3122                                                  const char *identity_hint);
3123 
3124 // SSL_use_psk_identity_hint configures server connections to advertise an
3125 // identity hint of |identity_hint|. It returns one on success and zero on
3126 // error.
3127 OPENSSL_EXPORT int SSL_use_psk_identity_hint(SSL *ssl,
3128                                              const char *identity_hint);
3129 
3130 // SSL_get_psk_identity_hint returns the PSK identity hint advertised for |ssl|
3131 // or NULL if there is none.
3132 OPENSSL_EXPORT const char *SSL_get_psk_identity_hint(const SSL *ssl);
3133 
3134 // SSL_get_psk_identity, after the handshake completes, returns the PSK identity
3135 // that was negotiated by |ssl| or NULL if PSK was not used.
3136 OPENSSL_EXPORT const char *SSL_get_psk_identity(const SSL *ssl);
3137 
3138 
3139 // Delegated credentials.
3140 //
3141 // *** EXPERIMENTAL — PRONE TO CHANGE ***
3142 //
3143 // draft-ietf-tls-subcerts is a proposed extension for TLS 1.3 and above that
3144 // allows an end point to use its certificate to delegate credentials for
3145 // authentication. If the peer indicates support for this extension, then this
3146 // host may use a delegated credential to sign the handshake. Once issued,
3147 // credentials can't be revoked. In order to mitigate the damage in case the
3148 // credential secret key is compromised, the credential is only valid for a
3149 // short time (days, hours, or even minutes). This library implements draft-03
3150 // of the protocol spec.
3151 //
3152 // The extension ID has not been assigned; we're using 0xff02 for the time
3153 // being. Currently only the server side is implemented.
3154 //
3155 // Servers configure a DC for use in the handshake via
3156 // |SSL_set1_delegated_credential|. It must be signed by the host's end-entity
3157 // certificate as defined in draft-ietf-tls-subcerts-03.
3158 
3159 // SSL_set1_delegated_credential configures the delegated credential (DC) that
3160 // will be sent to the peer for the current connection. |dc| is the DC in wire
3161 // format, and |pkey| or |key_method| is the corresponding private key.
3162 // Currently (as of draft-03), only servers may configure a DC to use in the
3163 // handshake.
3164 //
3165 // The DC will only be used if the protocol version is correct and the signature
3166 // scheme is supported by the peer. If not, the DC will not be negotiated and
3167 // the handshake will use the private key (or private key method) associated
3168 // with the certificate.
3169 OPENSSL_EXPORT int SSL_set1_delegated_credential(
3170     SSL *ssl, CRYPTO_BUFFER *dc, EVP_PKEY *pkey,
3171     const SSL_PRIVATE_KEY_METHOD *key_method);
3172 
3173 // SSL_delegated_credential_used returns one if a delegated credential was used
3174 // and zero otherwise.
3175 OPENSSL_EXPORT int SSL_delegated_credential_used(const SSL *ssl);
3176 
3177 
3178 // QUIC integration.
3179 //
3180 // QUIC acts as an underlying transport for the TLS 1.3 handshake. The following
3181 // functions allow a QUIC implementation to serve as the underlying transport as
3182 // described in draft-ietf-quic-tls.
3183 //
3184 // When configured for QUIC, |SSL_do_handshake| will drive the handshake as
3185 // before, but it will not use the configured |BIO|. It will call functions on
3186 // |SSL_QUIC_METHOD| to configure secrets and send data. If data is needed from
3187 // the peer, it will return |SSL_ERROR_WANT_READ|. As the caller receives data
3188 // it can decrypt, it calls |SSL_provide_quic_data|. Subsequent
3189 // |SSL_do_handshake| calls will then consume that data and progress the
3190 // handshake. After the handshake is complete, the caller should continue to
3191 // call |SSL_provide_quic_data| for any post-handshake data, followed by
3192 // |SSL_process_quic_post_handshake| to process it. It is an error to call
3193 // |SSL_read| and |SSL_write| in QUIC.
3194 //
3195 // 0-RTT behaves similarly to |TLS_method|'s usual behavior. |SSL_do_handshake|
3196 // returns early as soon as the client (respectively, server) is allowed to send
3197 // 0-RTT (respectively, half-RTT) data. The caller should then call
3198 // |SSL_do_handshake| again to consume the remaining handshake messages and
3199 // confirm the handshake. As a client, |SSL_ERROR_EARLY_DATA_REJECTED| and
3200 // |SSL_reset_early_data_reject| behave as usual.
3201 //
3202 // See https://tools.ietf.org/html/draft-ietf-quic-tls-15#section-4.1 for more
3203 // details.
3204 //
3205 // To avoid DoS attacks, the QUIC implementation must limit the amount of data
3206 // being queued up. The implementation can call
3207 // |SSL_quic_max_handshake_flight_len| to get the maximum buffer length at each
3208 // encryption level.
3209 //
3210 // QUIC implementations must additionally configure transport parameters with
3211 // |SSL_set_quic_transport_params|. |SSL_get_peer_quic_transport_params| may be
3212 // used to query the value received from the peer. BoringSSL handles this
3213 // extension as an opaque byte string. The caller is responsible for serializing
3214 // and parsing them. See draft-ietf-quic-transport (section 7.3) for details.
3215 //
3216 // QUIC additionally imposes restrictions on 0-RTT. In particular, the QUIC
3217 // transport layer requires that if a server accepts 0-RTT data, then the
3218 // transport parameters sent on the resumed connection must not lower any limits
3219 // compared to the transport parameters that the server sent on the connection
3220 // where the ticket for 0-RTT was issued. In effect, the server must remember
3221 // the transport parameters with the ticket. Application protocols running on
3222 // QUIC may impose similar restrictions, for example HTTP/3's restrictions on
3223 // SETTINGS frames.
3224 //
3225 // BoringSSL implements this check by doing a byte-for-byte comparison of an
3226 // opaque context passed in by the server. This context must be the same on the
3227 // connection where the ticket was issued and the connection where that ticket
3228 // is used for 0-RTT. If there is a mismatch, or the context was not set,
3229 // BoringSSL will reject early data (but not reject the resumption attempt).
3230 // This context is set via |SSL_set_quic_early_data_context| and should cover
3231 // both transport parameters and any application state.
3232 // |SSL_set_quic_early_data_context| must be called on the server with a
3233 // non-empty context if the server is to support 0-RTT in QUIC.
3234 //
3235 // BoringSSL does not perform any client-side checks on the transport
3236 // parameters received from a server that also accepted early data. It is up to
3237 // the caller to verify that the received transport parameters do not lower any
3238 // limits, and to close the QUIC connection if that is not the case. The same
3239 // holds for any application protocol state remembered for 0-RTT, e.g. HTTP/3
3240 // SETTINGS.
3241 
3242 // ssl_encryption_level_t represents a specific QUIC encryption level used to
3243 // transmit handshake messages.
3244 enum ssl_encryption_level_t BORINGSSL_ENUM_INT {
3245   ssl_encryption_initial = 0,
3246   ssl_encryption_early_data,
3247   ssl_encryption_handshake,
3248   ssl_encryption_application,
3249 };
3250 
3251 // ssl_quic_method_st (aka |SSL_QUIC_METHOD|) describes custom QUIC hooks.
3252 struct ssl_quic_method_st {
3253   // set_read_secret configures the read secret and cipher suite for the given
3254   // encryption level. It returns one on success and zero to terminate the
3255   // handshake with an error. It will be called at most once per encryption
3256   // level.
3257   //
3258   // BoringSSL will not release read keys before QUIC may use them. Once a level
3259   // has been initialized, QUIC may begin processing data from it. Handshake
3260   // data should be passed to |SSL_provide_quic_data| and application data (if
3261   // |level| is |ssl_encryption_early_data| or |ssl_encryption_application|) may
3262   // be processed according to the rules of the QUIC protocol.
3263   //
3264   // QUIC ACKs packets at the same encryption level they were received at,
3265   // except that client |ssl_encryption_early_data| (0-RTT) packets trigger
3266   // server |ssl_encryption_application| (1-RTT) ACKs. BoringSSL will always
3267   // install ACK-writing keys with |set_write_secret| before the packet-reading
3268   // keys with |set_read_secret|. This ensures the caller can always ACK any
3269   // packet it decrypts. Note this means the server installs 1-RTT write keys
3270   // before 0-RTT read keys.
3271   //
3272   // The converse is not true. An encryption level may be configured with write
3273   // secrets a roundtrip before the corresponding secrets for reading ACKs is
3274   // available.
3275   int (*set_read_secret)(SSL *ssl, enum ssl_encryption_level_t level,
3276                          const SSL_CIPHER *cipher, const uint8_t *secret,
3277                          size_t secret_len);
3278   // set_write_secret behaves like |set_read_secret| but configures the write
3279   // secret and cipher suite for the given encryption level. It will be called
3280   // at most once per encryption level.
3281   //
3282   // BoringSSL will not release write keys before QUIC may use them. If |level|
3283   // is |ssl_encryption_early_data| or |ssl_encryption_application|, QUIC may
3284   // begin sending application data at |level|. However, note that BoringSSL
3285   // configures server |ssl_encryption_application| write keys before the client
3286   // Finished. This allows QUIC to send half-RTT data, but the handshake is not
3287   // confirmed at this point and, if requesting client certificates, the client
3288   // is not yet authenticated.
3289   //
3290   // See |set_read_secret| for additional invariants between packets and their
3291   // ACKs.
3292   //
3293   // Note that, on 0-RTT reject, the |ssl_encryption_early_data| write secret
3294   // may use a different cipher suite from the other keys.
3295   int (*set_write_secret)(SSL *ssl, enum ssl_encryption_level_t level,
3296                           const SSL_CIPHER *cipher, const uint8_t *secret,
3297                           size_t secret_len);
3298   // add_handshake_data adds handshake data to the current flight at the given
3299   // encryption level. It returns one on success and zero on error.
3300   //
3301   // BoringSSL will pack data from a single encryption level together, but a
3302   // single handshake flight may include multiple encryption levels. Callers
3303   // should defer writing data to the network until |flush_flight| to better
3304   // pack QUIC packets into transport datagrams.
3305   //
3306   // If |level| is not |ssl_encryption_initial|, this function will not be
3307   // called before |level| is initialized with |set_write_secret|.
3308   int (*add_handshake_data)(SSL *ssl, enum ssl_encryption_level_t level,
3309                             const uint8_t *data, size_t len);
3310   // flush_flight is called when the current flight is complete and should be
3311   // written to the transport. Note a flight may contain data at several
3312   // encryption levels. It returns one on success and zero on error.
3313   int (*flush_flight)(SSL *ssl);
3314   // send_alert sends a fatal alert at the specified encryption level. It
3315   // returns one on success and zero on error.
3316   //
3317   // If |level| is not |ssl_encryption_initial|, this function will not be
3318   // called before |level| is initialized with |set_write_secret|.
3319   int (*send_alert)(SSL *ssl, enum ssl_encryption_level_t level, uint8_t alert);
3320 };
3321 
3322 // SSL_quic_max_handshake_flight_len returns returns the maximum number of bytes
3323 // that may be received at the given encryption level. This function should be
3324 // used to limit buffering in the QUIC implementation.
3325 //
3326 // See https://tools.ietf.org/html/draft-ietf-quic-transport-16#section-4.4.
3327 OPENSSL_EXPORT size_t SSL_quic_max_handshake_flight_len(
3328     const SSL *ssl, enum ssl_encryption_level_t level);
3329 
3330 // SSL_quic_read_level returns the current read encryption level.
3331 //
3332 // TODO(davidben): Is it still necessary to expose this function to callers?
3333 // QUICHE does not use it.
3334 OPENSSL_EXPORT enum ssl_encryption_level_t SSL_quic_read_level(const SSL *ssl);
3335 
3336 // SSL_quic_write_level returns the current write encryption level.
3337 //
3338 // TODO(davidben): Is it still necessary to expose this function to callers?
3339 // QUICHE does not use it.
3340 OPENSSL_EXPORT enum ssl_encryption_level_t SSL_quic_write_level(const SSL *ssl);
3341 
3342 // SSL_provide_quic_data provides data from QUIC at a particular encryption
3343 // level |level|. It returns one on success and zero on error. Note this
3344 // function will return zero if the handshake is not expecting data from |level|
3345 // at this time. The QUIC implementation should then close the connection with
3346 // an error.
3347 OPENSSL_EXPORT int SSL_provide_quic_data(SSL *ssl,
3348                                          enum ssl_encryption_level_t level,
3349                                          const uint8_t *data, size_t len);
3350 
3351 
3352 // SSL_process_quic_post_handshake processes any data that QUIC has provided
3353 // after the handshake has completed. This includes NewSessionTicket messages
3354 // sent by the server. It returns one on success and zero on error.
3355 OPENSSL_EXPORT int SSL_process_quic_post_handshake(SSL *ssl);
3356 
3357 // SSL_CTX_set_quic_method configures the QUIC hooks. This should only be
3358 // configured with a minimum version of TLS 1.3. |quic_method| must remain valid
3359 // for the lifetime of |ctx|. It returns one on success and zero on error.
3360 OPENSSL_EXPORT int SSL_CTX_set_quic_method(SSL_CTX *ctx,
3361                                            const SSL_QUIC_METHOD *quic_method);
3362 
3363 // SSL_set_quic_method configures the QUIC hooks. This should only be
3364 // configured with a minimum version of TLS 1.3. |quic_method| must remain valid
3365 // for the lifetime of |ssl|. It returns one on success and zero on error.
3366 OPENSSL_EXPORT int SSL_set_quic_method(SSL *ssl,
3367                                        const SSL_QUIC_METHOD *quic_method);
3368 
3369 // SSL_set_quic_transport_params configures |ssl| to send |params| (of length
3370 // |params_len|) in the quic_transport_parameters extension in either the
3371 // ClientHello or EncryptedExtensions handshake message. It is an error to set
3372 // transport parameters if |ssl| is not configured for QUIC. The buffer pointed
3373 // to by |params| only need be valid for the duration of the call to this
3374 // function. This function returns 1 on success and 0 on failure.
3375 OPENSSL_EXPORT int SSL_set_quic_transport_params(SSL *ssl,
3376                                                  const uint8_t *params,
3377                                                  size_t params_len);
3378 
3379 // SSL_get_peer_quic_transport_params provides the caller with the value of the
3380 // quic_transport_parameters extension sent by the peer. A pointer to the buffer
3381 // containing the TransportParameters will be put in |*out_params|, and its
3382 // length in |*params_len|. This buffer will be valid for the lifetime of the
3383 // |SSL|. If no params were received from the peer, |*out_params_len| will be 0.
3384 OPENSSL_EXPORT void SSL_get_peer_quic_transport_params(
3385     const SSL *ssl, const uint8_t **out_params, size_t *out_params_len);
3386 
3387 // SSL_set_quic_use_legacy_codepoint configures whether to use the legacy QUIC
3388 // extension codepoint 0xffa5 as opposed to the official value 57. Call with
3389 // |use_legacy| set to 1 to use 0xffa5 and call with 0 to use 57. The default
3390 // value for this is currently 1 but it will change to 0 at a later date.
3391 OPENSSL_EXPORT void SSL_set_quic_use_legacy_codepoint(SSL *ssl, int use_legacy);
3392 
3393 // SSL_set_quic_early_data_context configures a context string in QUIC servers
3394 // for accepting early data. If a resumption connection offers early data, the
3395 // server will check if the value matches that of the connection which minted
3396 // the ticket. If not, resumption still succeeds but early data is rejected.
3397 // This should include all QUIC Transport Parameters except ones specified that
3398 // the client MUST NOT remember. This should also include any application
3399 // protocol-specific state. For HTTP/3, this should be the serialized server
3400 // SETTINGS frame and the QUIC Transport Parameters (except the stateless reset
3401 // token).
3402 //
3403 // This function may be called before |SSL_do_handshake| or during server
3404 // certificate selection. It returns 1 on success and 0 on failure.
3405 OPENSSL_EXPORT int SSL_set_quic_early_data_context(SSL *ssl,
3406                                                    const uint8_t *context,
3407                                                    size_t context_len);
3408 
3409 
3410 // Early data.
3411 //
3412 // WARNING: 0-RTT support in BoringSSL is currently experimental and not fully
3413 // implemented. It may cause interoperability or security failures when used.
3414 //
3415 // Early data, or 0-RTT, is a feature in TLS 1.3 which allows clients to send
3416 // data on the first flight during a resumption handshake. This can save a
3417 // round-trip in some application protocols.
3418 //
3419 // WARNING: A 0-RTT handshake has different security properties from normal
3420 // handshake, so it is off by default unless opted in. In particular, early data
3421 // is replayable by a network attacker. Callers must account for this when
3422 // sending or processing data before the handshake is confirmed. See RFC 8446
3423 // for more information.
3424 //
3425 // As a server, if early data is accepted, |SSL_do_handshake| will complete as
3426 // soon as the ClientHello is processed and server flight sent. |SSL_write| may
3427 // be used to send half-RTT data. |SSL_read| will consume early data and
3428 // transition to 1-RTT data as appropriate. Prior to the transition,
3429 // |SSL_in_init| will report the handshake is still in progress. Callers may use
3430 // it or |SSL_in_early_data| to defer or reject requests as needed.
3431 //
3432 // Early data as a client is more complex. If the offered session (see
3433 // |SSL_set_session|) is 0-RTT-capable, the handshake will return after sending
3434 // the ClientHello. The predicted peer certificates and ALPN protocol will be
3435 // available via the usual APIs. |SSL_write| will write early data, up to the
3436 // session's limit. Writes past this limit and |SSL_read| will complete the
3437 // handshake before continuing. Callers may also call |SSL_do_handshake| again
3438 // to complete the handshake sooner.
3439 //
3440 // If the server accepts early data, the handshake will succeed. |SSL_read| and
3441 // |SSL_write| will then act as in a 1-RTT handshake. The peer certificates and
3442 // ALPN protocol will be as predicted and need not be re-queried.
3443 //
3444 // If the server rejects early data, |SSL_do_handshake| (and thus |SSL_read| and
3445 // |SSL_write|) will then fail with |SSL_get_error| returning
3446 // |SSL_ERROR_EARLY_DATA_REJECTED|. The caller should treat this as a connection
3447 // error and most likely perform a high-level retry. Note the server may still
3448 // have processed the early data due to attacker replays.
3449 //
3450 // To then continue the handshake on the original connection, use
3451 // |SSL_reset_early_data_reject|. The connection will then behave as one which
3452 // had not yet completed the handshake. This allows a faster retry than making a
3453 // fresh connection. |SSL_do_handshake| will complete the full handshake,
3454 // possibly resulting in different peer certificates, ALPN protocol, and other
3455 // properties. The caller must disregard any values from before the reset and
3456 // query again.
3457 //
3458 // Finally, to implement the fallback described in RFC 8446 appendix D.3, retry
3459 // on a fresh connection without 0-RTT if the handshake fails with
3460 // |SSL_R_WRONG_VERSION_ON_EARLY_DATA|.
3461 
3462 // SSL_CTX_set_early_data_enabled sets whether early data is allowed to be used
3463 // with resumptions using |ctx|.
3464 OPENSSL_EXPORT void SSL_CTX_set_early_data_enabled(SSL_CTX *ctx, int enabled);
3465 
3466 // SSL_set_early_data_enabled sets whether early data is allowed to be used
3467 // with resumptions using |ssl|. See |SSL_CTX_set_early_data_enabled| for more
3468 // information.
3469 OPENSSL_EXPORT void SSL_set_early_data_enabled(SSL *ssl, int enabled);
3470 
3471 // SSL_in_early_data returns one if |ssl| has a pending handshake that has
3472 // progressed enough to send or receive early data. Clients may call |SSL_write|
3473 // to send early data, but |SSL_read| will complete the handshake before
3474 // accepting application data. Servers may call |SSL_read| to read early data
3475 // and |SSL_write| to send half-RTT data.
3476 OPENSSL_EXPORT int SSL_in_early_data(const SSL *ssl);
3477 
3478 // SSL_SESSION_early_data_capable returns whether early data would have been
3479 // attempted with |session| if enabled.
3480 OPENSSL_EXPORT int SSL_SESSION_early_data_capable(const SSL_SESSION *session);
3481 
3482 // SSL_SESSION_copy_without_early_data returns a copy of |session| with early
3483 // data disabled. If |session| already does not support early data, it returns
3484 // |session| with the reference count increased. The caller takes ownership of
3485 // the result and must release it with |SSL_SESSION_free|.
3486 //
3487 // This function may be used on the client to clear early data support from
3488 // existing sessions when the server rejects early data. In particular,
3489 // |SSL_R_WRONG_VERSION_ON_EARLY_DATA| requires a fresh connection to retry, and
3490 // the client would not want 0-RTT enabled for the next connection attempt.
3491 OPENSSL_EXPORT SSL_SESSION *SSL_SESSION_copy_without_early_data(
3492     SSL_SESSION *session);
3493 
3494 // SSL_early_data_accepted returns whether early data was accepted on the
3495 // handshake performed by |ssl|.
3496 OPENSSL_EXPORT int SSL_early_data_accepted(const SSL *ssl);
3497 
3498 // SSL_reset_early_data_reject resets |ssl| after an early data reject. All
3499 // 0-RTT state is discarded, including any pending |SSL_write| calls. The caller
3500 // should treat |ssl| as a logically fresh connection, usually by driving the
3501 // handshake to completion using |SSL_do_handshake|.
3502 //
3503 // It is an error to call this function on an |SSL| object that is not signaling
3504 // |SSL_ERROR_EARLY_DATA_REJECTED|.
3505 OPENSSL_EXPORT void SSL_reset_early_data_reject(SSL *ssl);
3506 
3507 // SSL_get_ticket_age_skew returns the difference, in seconds, between the
3508 // client-sent ticket age and the server-computed value in TLS 1.3 server
3509 // connections which resumed a session.
3510 OPENSSL_EXPORT int32_t SSL_get_ticket_age_skew(const SSL *ssl);
3511 
3512 // An ssl_early_data_reason_t describes why 0-RTT was accepted or rejected.
3513 // These values are persisted to logs. Entries should not be renumbered and
3514 // numeric values should never be reused.
3515 enum ssl_early_data_reason_t BORINGSSL_ENUM_INT {
3516   // The handshake has not progressed far enough for the 0-RTT status to be
3517   // known.
3518   ssl_early_data_unknown = 0,
3519   // 0-RTT is disabled for this connection.
3520   ssl_early_data_disabled = 1,
3521   // 0-RTT was accepted.
3522   ssl_early_data_accepted = 2,
3523   // The negotiated protocol version does not support 0-RTT.
3524   ssl_early_data_protocol_version = 3,
3525   // The peer declined to offer or accept 0-RTT for an unknown reason.
3526   ssl_early_data_peer_declined = 4,
3527   // The client did not offer a session.
3528   ssl_early_data_no_session_offered = 5,
3529   // The server declined to resume the session.
3530   ssl_early_data_session_not_resumed = 6,
3531   // The session does not support 0-RTT.
3532   ssl_early_data_unsupported_for_session = 7,
3533   // The server sent a HelloRetryRequest.
3534   ssl_early_data_hello_retry_request = 8,
3535   // The negotiated ALPN protocol did not match the session.
3536   ssl_early_data_alpn_mismatch = 9,
3537   // The connection negotiated Channel ID, which is incompatible with 0-RTT.
3538   ssl_early_data_channel_id = 10,
3539   // The connection negotiated token binding, which is incompatible with 0-RTT.
3540   ssl_early_data_token_binding = 11,
3541   // The client and server ticket age were too far apart.
3542   ssl_early_data_ticket_age_skew = 12,
3543   // QUIC parameters differ between this connection and the original.
3544   ssl_early_data_quic_parameter_mismatch = 13,
3545   // The application settings did not match the session.
3546   ssl_early_data_alps_mismatch = 14,
3547   // The value of the largest entry.
3548   ssl_early_data_reason_max_value = ssl_early_data_alps_mismatch,
3549 };
3550 
3551 // SSL_get_early_data_reason returns details why 0-RTT was accepted or rejected
3552 // on |ssl|. This is primarily useful on the server.
3553 OPENSSL_EXPORT enum ssl_early_data_reason_t SSL_get_early_data_reason(
3554     const SSL *ssl);
3555 
3556 // SSL_early_data_reason_string returns a string representation for |reason|, or
3557 // NULL if |reason| is unknown. This function may be used for logging.
3558 OPENSSL_EXPORT const char *SSL_early_data_reason_string(
3559     enum ssl_early_data_reason_t reason);
3560 
3561 
3562 // Encrypted Client Hello.
3563 //
3564 // ECH is a mechanism for encrypting the entire ClientHello message in TLS 1.3.
3565 // This can prevent observers from seeing cleartext information about the
3566 // connection, such as the server_name extension.
3567 //
3568 // ECH support in BoringSSL is still experimental and under development.
3569 //
3570 // See https://tools.ietf.org/html/draft-ietf-tls-esni-09.
3571 
3572 // SSL_set_enable_ech_grease configures whether the client may send ECH GREASE
3573 // as part of this connection.
3574 OPENSSL_EXPORT void SSL_set_enable_ech_grease(SSL *ssl, int enable);
3575 
3576 
3577 // Alerts.
3578 //
3579 // TLS uses alerts to signal error conditions. Alerts have a type (warning or
3580 // fatal) and description. OpenSSL internally handles fatal alerts with
3581 // dedicated error codes (see |SSL_AD_REASON_OFFSET|). Except for close_notify,
3582 // warning alerts are silently ignored and may only be surfaced with
3583 // |SSL_CTX_set_info_callback|.
3584 
3585 // SSL_AD_REASON_OFFSET is the offset between error reasons and |SSL_AD_*|
3586 // values. Any error code under |ERR_LIB_SSL| with an error reason above this
3587 // value corresponds to an alert description. Consumers may add or subtract
3588 // |SSL_AD_REASON_OFFSET| to convert between them.
3589 //
3590 // make_errors.go reserves error codes above 1000 for manually-assigned errors.
3591 // This value must be kept in sync with reservedReasonCode in make_errors.h
3592 #define SSL_AD_REASON_OFFSET 1000
3593 
3594 // SSL_AD_* are alert descriptions.
3595 #define SSL_AD_CLOSE_NOTIFY SSL3_AD_CLOSE_NOTIFY
3596 #define SSL_AD_UNEXPECTED_MESSAGE SSL3_AD_UNEXPECTED_MESSAGE
3597 #define SSL_AD_BAD_RECORD_MAC SSL3_AD_BAD_RECORD_MAC
3598 #define SSL_AD_DECRYPTION_FAILED TLS1_AD_DECRYPTION_FAILED
3599 #define SSL_AD_RECORD_OVERFLOW TLS1_AD_RECORD_OVERFLOW
3600 #define SSL_AD_DECOMPRESSION_FAILURE SSL3_AD_DECOMPRESSION_FAILURE
3601 #define SSL_AD_HANDSHAKE_FAILURE SSL3_AD_HANDSHAKE_FAILURE
3602 #define SSL_AD_NO_CERTIFICATE SSL3_AD_NO_CERTIFICATE  // Legacy SSL 3.0 value
3603 #define SSL_AD_BAD_CERTIFICATE SSL3_AD_BAD_CERTIFICATE
3604 #define SSL_AD_UNSUPPORTED_CERTIFICATE SSL3_AD_UNSUPPORTED_CERTIFICATE
3605 #define SSL_AD_CERTIFICATE_REVOKED SSL3_AD_CERTIFICATE_REVOKED
3606 #define SSL_AD_CERTIFICATE_EXPIRED SSL3_AD_CERTIFICATE_EXPIRED
3607 #define SSL_AD_CERTIFICATE_UNKNOWN SSL3_AD_CERTIFICATE_UNKNOWN
3608 #define SSL_AD_ILLEGAL_PARAMETER SSL3_AD_ILLEGAL_PARAMETER
3609 #define SSL_AD_UNKNOWN_CA TLS1_AD_UNKNOWN_CA
3610 #define SSL_AD_ACCESS_DENIED TLS1_AD_ACCESS_DENIED
3611 #define SSL_AD_DECODE_ERROR TLS1_AD_DECODE_ERROR
3612 #define SSL_AD_DECRYPT_ERROR TLS1_AD_DECRYPT_ERROR
3613 #define SSL_AD_EXPORT_RESTRICTION TLS1_AD_EXPORT_RESTRICTION
3614 #define SSL_AD_PROTOCOL_VERSION TLS1_AD_PROTOCOL_VERSION
3615 #define SSL_AD_INSUFFICIENT_SECURITY TLS1_AD_INSUFFICIENT_SECURITY
3616 #define SSL_AD_INTERNAL_ERROR TLS1_AD_INTERNAL_ERROR
3617 #define SSL_AD_INAPPROPRIATE_FALLBACK SSL3_AD_INAPPROPRIATE_FALLBACK
3618 #define SSL_AD_USER_CANCELLED TLS1_AD_USER_CANCELLED
3619 #define SSL_AD_NO_RENEGOTIATION TLS1_AD_NO_RENEGOTIATION
3620 #define SSL_AD_MISSING_EXTENSION TLS1_AD_MISSING_EXTENSION
3621 #define SSL_AD_UNSUPPORTED_EXTENSION TLS1_AD_UNSUPPORTED_EXTENSION
3622 #define SSL_AD_CERTIFICATE_UNOBTAINABLE TLS1_AD_CERTIFICATE_UNOBTAINABLE
3623 #define SSL_AD_UNRECOGNIZED_NAME TLS1_AD_UNRECOGNIZED_NAME
3624 #define SSL_AD_BAD_CERTIFICATE_STATUS_RESPONSE \
3625   TLS1_AD_BAD_CERTIFICATE_STATUS_RESPONSE
3626 #define SSL_AD_BAD_CERTIFICATE_HASH_VALUE TLS1_AD_BAD_CERTIFICATE_HASH_VALUE
3627 #define SSL_AD_UNKNOWN_PSK_IDENTITY TLS1_AD_UNKNOWN_PSK_IDENTITY
3628 #define SSL_AD_CERTIFICATE_REQUIRED TLS1_AD_CERTIFICATE_REQUIRED
3629 #define SSL_AD_NO_APPLICATION_PROTOCOL TLS1_AD_NO_APPLICATION_PROTOCOL
3630 
3631 // SSL_alert_type_string_long returns a string description of |value| as an
3632 // alert type (warning or fatal).
3633 OPENSSL_EXPORT const char *SSL_alert_type_string_long(int value);
3634 
3635 // SSL_alert_desc_string_long returns a string description of |value| as an
3636 // alert description or "unknown" if unknown.
3637 OPENSSL_EXPORT const char *SSL_alert_desc_string_long(int value);
3638 
3639 // SSL_send_fatal_alert sends a fatal alert over |ssl| of the specified type,
3640 // which should be one of the |SSL_AD_*| constants. It returns one on success
3641 // and <= 0 on error. The caller should pass the return value into
3642 // |SSL_get_error| to determine how to proceed. Once this function has been
3643 // called, future calls to |SSL_write| will fail.
3644 //
3645 // If retrying a failed operation due to |SSL_ERROR_WANT_WRITE|, subsequent
3646 // calls must use the same |alert| parameter.
3647 OPENSSL_EXPORT int SSL_send_fatal_alert(SSL *ssl, uint8_t alert);
3648 
3649 
3650 // ex_data functions.
3651 //
3652 // See |ex_data.h| for details.
3653 
3654 OPENSSL_EXPORT int SSL_set_ex_data(SSL *ssl, int idx, void *data);
3655 OPENSSL_EXPORT void *SSL_get_ex_data(const SSL *ssl, int idx);
3656 OPENSSL_EXPORT int SSL_get_ex_new_index(long argl, void *argp,
3657                                         CRYPTO_EX_unused *unused,
3658                                         CRYPTO_EX_dup *dup_unused,
3659                                         CRYPTO_EX_free *free_func);
3660 
3661 OPENSSL_EXPORT int SSL_SESSION_set_ex_data(SSL_SESSION *session, int idx,
3662                                            void *data);
3663 OPENSSL_EXPORT void *SSL_SESSION_get_ex_data(const SSL_SESSION *session,
3664                                              int idx);
3665 OPENSSL_EXPORT int SSL_SESSION_get_ex_new_index(long argl, void *argp,
3666                                                 CRYPTO_EX_unused *unused,
3667                                                 CRYPTO_EX_dup *dup_unused,
3668                                                 CRYPTO_EX_free *free_func);
3669 
3670 OPENSSL_EXPORT int SSL_CTX_set_ex_data(SSL_CTX *ctx, int idx, void *data);
3671 OPENSSL_EXPORT void *SSL_CTX_get_ex_data(const SSL_CTX *ctx, int idx);
3672 OPENSSL_EXPORT int SSL_CTX_get_ex_new_index(long argl, void *argp,
3673                                             CRYPTO_EX_unused *unused,
3674                                             CRYPTO_EX_dup *dup_unused,
3675                                             CRYPTO_EX_free *free_func);
3676 
3677 
3678 // Low-level record-layer state.
3679 
3680 // SSL_get_ivs sets |*out_iv_len| to the length of the IVs for the ciphers
3681 // underlying |ssl| and sets |*out_read_iv| and |*out_write_iv| to point to the
3682 // current IVs for the read and write directions. This is only meaningful for
3683 // connections with implicit IVs (i.e. CBC mode with TLS 1.0).
3684 //
3685 // It returns one on success or zero on error.
3686 OPENSSL_EXPORT int SSL_get_ivs(const SSL *ssl, const uint8_t **out_read_iv,
3687                                const uint8_t **out_write_iv,
3688                                size_t *out_iv_len);
3689 
3690 // SSL_get_key_block_len returns the length of |ssl|'s key block. It is an error
3691 // to call this function during a handshake.
3692 OPENSSL_EXPORT size_t SSL_get_key_block_len(const SSL *ssl);
3693 
3694 // SSL_generate_key_block generates |out_len| bytes of key material for |ssl|'s
3695 // current connection state. It is an error to call this function during a
3696 // handshake.
3697 OPENSSL_EXPORT int SSL_generate_key_block(const SSL *ssl, uint8_t *out,
3698                                           size_t out_len);
3699 
3700 // SSL_get_read_sequence returns, in TLS, the expected sequence number of the
3701 // next incoming record in the current epoch. In DTLS, it returns the maximum
3702 // sequence number received in the current epoch and includes the epoch number
3703 // in the two most significant bytes.
3704 OPENSSL_EXPORT uint64_t SSL_get_read_sequence(const SSL *ssl);
3705 
3706 // SSL_get_write_sequence returns the sequence number of the next outgoing
3707 // record in the current epoch. In DTLS, it includes the epoch number in the
3708 // two most significant bytes.
3709 OPENSSL_EXPORT uint64_t SSL_get_write_sequence(const SSL *ssl);
3710 
3711 
3712 // Obscure functions.
3713 
3714 // SSL_CTX_set_msg_callback installs |cb| as the message callback for |ctx|.
3715 // This callback will be called when sending or receiving low-level record
3716 // headers, complete handshake messages, ChangeCipherSpec, and alerts.
3717 // |write_p| is one for outgoing messages and zero for incoming messages.
3718 //
3719 // For each record header, |cb| is called with |version| = 0 and |content_type|
3720 // = |SSL3_RT_HEADER|. The |len| bytes from |buf| contain the header. Note that
3721 // this does not include the record body. If the record is sealed, the length
3722 // in the header is the length of the ciphertext.
3723 //
3724 // For each handshake message, ChangeCipherSpec, and alert, |version| is the
3725 // protocol version and |content_type| is the corresponding record type. The
3726 // |len| bytes from |buf| contain the handshake message, one-byte
3727 // ChangeCipherSpec body, and two-byte alert, respectively.
3728 //
3729 // For a V2ClientHello, |version| is |SSL2_VERSION|, |content_type| is zero, and
3730 // the |len| bytes from |buf| contain the V2ClientHello structure.
3731 OPENSSL_EXPORT void SSL_CTX_set_msg_callback(
3732     SSL_CTX *ctx, void (*cb)(int write_p, int version, int content_type,
3733                              const void *buf, size_t len, SSL *ssl, void *arg));
3734 
3735 // SSL_CTX_set_msg_callback_arg sets the |arg| parameter of the message
3736 // callback.
3737 OPENSSL_EXPORT void SSL_CTX_set_msg_callback_arg(SSL_CTX *ctx, void *arg);
3738 
3739 // SSL_set_msg_callback installs |cb| as the message callback of |ssl|. See
3740 // |SSL_CTX_set_msg_callback| for when this callback is called.
3741 OPENSSL_EXPORT void SSL_set_msg_callback(
3742     SSL *ssl, void (*cb)(int write_p, int version, int content_type,
3743                          const void *buf, size_t len, SSL *ssl, void *arg));
3744 
3745 // SSL_set_msg_callback_arg sets the |arg| parameter of the message callback.
3746 OPENSSL_EXPORT void SSL_set_msg_callback_arg(SSL *ssl, void *arg);
3747 
3748 // SSL_CTX_set_keylog_callback configures a callback to log key material. This
3749 // is intended for debugging use with tools like Wireshark. The |cb| function
3750 // should log |line| followed by a newline, synchronizing with any concurrent
3751 // access to the log.
3752 //
3753 // The format is described in
3754 // https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format.
3755 OPENSSL_EXPORT void SSL_CTX_set_keylog_callback(
3756     SSL_CTX *ctx, void (*cb)(const SSL *ssl, const char *line));
3757 
3758 // SSL_CTX_get_keylog_callback returns the callback configured by
3759 // |SSL_CTX_set_keylog_callback|.
3760 OPENSSL_EXPORT void (*SSL_CTX_get_keylog_callback(const SSL_CTX *ctx))(
3761     const SSL *ssl, const char *line);
3762 
3763 // SSL_CTX_set_current_time_cb configures a callback to retrieve the current
3764 // time, which should be set in |*out_clock|. This can be used for testing
3765 // purposes; for example, a callback can be configured that returns a time
3766 // set explicitly by the test. The |ssl| pointer passed to |cb| is always null.
3767 OPENSSL_EXPORT void SSL_CTX_set_current_time_cb(
3768     SSL_CTX *ctx, void (*cb)(const SSL *ssl, struct timeval *out_clock));
3769 
3770 // SSL_set_shed_handshake_config allows some of the configuration of |ssl| to be
3771 // freed after its handshake completes.  Once configuration has been shed, APIs
3772 // that query it may fail.  "Configuration" in this context means anything that
3773 // was set by the caller, as distinct from information derived from the
3774 // handshake.  For example, |SSL_get_ciphers| queries how the |SSL| was
3775 // configured by the caller, and fails after configuration has been shed,
3776 // whereas |SSL_get_cipher| queries the result of the handshake, and is
3777 // unaffected by configuration shedding.
3778 //
3779 // If configuration shedding is enabled, it is an error to call |SSL_clear|.
3780 //
3781 // Note that configuration shedding as a client additionally depends on
3782 // renegotiation being disabled (see |SSL_set_renegotiate_mode|). If
3783 // renegotiation is possible, the configuration will be retained. If
3784 // configuration shedding is enabled and renegotiation later disabled after the
3785 // handshake, |SSL_set_renegotiate_mode| will shed configuration then. This may
3786 // be useful for clients which support renegotiation with some ALPN protocols,
3787 // such as HTTP/1.1, and not others, such as HTTP/2.
3788 OPENSSL_EXPORT void SSL_set_shed_handshake_config(SSL *ssl, int enable);
3789 
3790 enum ssl_renegotiate_mode_t BORINGSSL_ENUM_INT {
3791   ssl_renegotiate_never = 0,
3792   ssl_renegotiate_once,
3793   ssl_renegotiate_freely,
3794   ssl_renegotiate_ignore,
3795   ssl_renegotiate_explicit,
3796 };
3797 
3798 // SSL_set_renegotiate_mode configures how |ssl|, a client, reacts to
3799 // renegotiation attempts by a server. If |ssl| is a server, peer-initiated
3800 // renegotiations are *always* rejected and this function does nothing.
3801 //
3802 // The renegotiation mode defaults to |ssl_renegotiate_never|, but may be set
3803 // at any point in a connection's lifetime. Set it to |ssl_renegotiate_once| to
3804 // allow one renegotiation, |ssl_renegotiate_freely| to allow all
3805 // renegotiations or |ssl_renegotiate_ignore| to ignore HelloRequest messages.
3806 // Note that ignoring HelloRequest messages may cause the connection to stall
3807 // if the server waits for the renegotiation to complete.
3808 //
3809 // If set to |ssl_renegotiate_explicit|, |SSL_read| and |SSL_peek| calls which
3810 // encounter a HelloRequest will pause with |SSL_ERROR_WANT_RENEGOTIATE|.
3811 // |SSL_write| will continue to work while paused. The caller may call
3812 // |SSL_renegotiate| to begin the renegotiation at a later point. This mode may
3813 // be used if callers wish to eagerly call |SSL_peek| without triggering a
3814 // renegotiation.
3815 //
3816 // If configuration shedding is enabled (see |SSL_set_shed_handshake_config|),
3817 // configuration is released if, at any point after the handshake, renegotiation
3818 // is disabled. It is not possible to switch from disabling renegotiation to
3819 // enabling it on a given connection. Callers that condition renegotiation on,
3820 // e.g., ALPN must enable renegotiation before the handshake and conditionally
3821 // disable it afterwards.
3822 //
3823 // There is no support in BoringSSL for initiating renegotiations as a client
3824 // or server.
3825 OPENSSL_EXPORT void SSL_set_renegotiate_mode(SSL *ssl,
3826                                              enum ssl_renegotiate_mode_t mode);
3827 
3828 // SSL_renegotiate starts a deferred renegotiation on |ssl| if it was configured
3829 // with |ssl_renegotiate_explicit| and has a pending HelloRequest. It returns
3830 // one on success and zero on error.
3831 //
3832 // This function does not do perform any I/O. On success, a subsequent
3833 // |SSL_do_handshake| call will run the handshake. |SSL_write| and
3834 // |SSL_read| will also complete the handshake before sending or receiving
3835 // application data.
3836 OPENSSL_EXPORT int SSL_renegotiate(SSL *ssl);
3837 
3838 // SSL_renegotiate_pending returns one if |ssl| is in the middle of a
3839 // renegotiation.
3840 OPENSSL_EXPORT int SSL_renegotiate_pending(SSL *ssl);
3841 
3842 // SSL_total_renegotiations returns the total number of renegotiation handshakes
3843 // performed by |ssl|. This includes the pending renegotiation, if any.
3844 OPENSSL_EXPORT int SSL_total_renegotiations(const SSL *ssl);
3845 
3846 // SSL_MAX_CERT_LIST_DEFAULT is the default maximum length, in bytes, of a peer
3847 // certificate chain.
3848 #define SSL_MAX_CERT_LIST_DEFAULT (1024 * 100)
3849 
3850 // SSL_CTX_get_max_cert_list returns the maximum length, in bytes, of a peer
3851 // certificate chain accepted by |ctx|.
3852 OPENSSL_EXPORT size_t SSL_CTX_get_max_cert_list(const SSL_CTX *ctx);
3853 
3854 // SSL_CTX_set_max_cert_list sets the maximum length, in bytes, of a peer
3855 // certificate chain to |max_cert_list|. This affects how much memory may be
3856 // consumed during the handshake.
3857 OPENSSL_EXPORT void SSL_CTX_set_max_cert_list(SSL_CTX *ctx,
3858                                               size_t max_cert_list);
3859 
3860 // SSL_get_max_cert_list returns the maximum length, in bytes, of a peer
3861 // certificate chain accepted by |ssl|.
3862 OPENSSL_EXPORT size_t SSL_get_max_cert_list(const SSL *ssl);
3863 
3864 // SSL_set_max_cert_list sets the maximum length, in bytes, of a peer
3865 // certificate chain to |max_cert_list|. This affects how much memory may be
3866 // consumed during the handshake.
3867 OPENSSL_EXPORT void SSL_set_max_cert_list(SSL *ssl, size_t max_cert_list);
3868 
3869 // SSL_CTX_set_max_send_fragment sets the maximum length, in bytes, of records
3870 // sent by |ctx|. Beyond this length, handshake messages and application data
3871 // will be split into multiple records. It returns one on success or zero on
3872 // error.
3873 OPENSSL_EXPORT int SSL_CTX_set_max_send_fragment(SSL_CTX *ctx,
3874                                                  size_t max_send_fragment);
3875 
3876 // SSL_set_max_send_fragment sets the maximum length, in bytes, of records sent
3877 // by |ssl|. Beyond this length, handshake messages and application data will
3878 // be split into multiple records. It returns one on success or zero on
3879 // error.
3880 OPENSSL_EXPORT int SSL_set_max_send_fragment(SSL *ssl,
3881                                              size_t max_send_fragment);
3882 
3883 // ssl_early_callback_ctx (aka |SSL_CLIENT_HELLO|) is passed to certain
3884 // callbacks that are called very early on during the server handshake. At this
3885 // point, much of the SSL* hasn't been filled out and only the ClientHello can
3886 // be depended on.
3887 typedef struct ssl_early_callback_ctx {
3888   SSL *ssl;
3889   const uint8_t *client_hello;
3890   size_t client_hello_len;
3891   uint16_t version;
3892   const uint8_t *random;
3893   size_t random_len;
3894   const uint8_t *session_id;
3895   size_t session_id_len;
3896   const uint8_t *cipher_suites;
3897   size_t cipher_suites_len;
3898   const uint8_t *compression_methods;
3899   size_t compression_methods_len;
3900   const uint8_t *extensions;
3901   size_t extensions_len;
3902 } SSL_CLIENT_HELLO;
3903 
3904 // ssl_select_cert_result_t enumerates the possible results from selecting a
3905 // certificate with |select_certificate_cb|.
3906 enum ssl_select_cert_result_t BORINGSSL_ENUM_INT {
3907   // ssl_select_cert_success indicates that the certificate selection was
3908   // successful.
3909   ssl_select_cert_success = 1,
3910   // ssl_select_cert_retry indicates that the operation could not be
3911   // immediately completed and must be reattempted at a later point.
3912   ssl_select_cert_retry = 0,
3913   // ssl_select_cert_error indicates that a fatal error occured and the
3914   // handshake should be terminated.
3915   ssl_select_cert_error = -1,
3916 };
3917 
3918 // SSL_early_callback_ctx_extension_get searches the extensions in
3919 // |client_hello| for an extension of the given type. If not found, it returns
3920 // zero. Otherwise it sets |out_data| to point to the extension contents (not
3921 // including the type and length bytes), sets |out_len| to the length of the
3922 // extension contents and returns one.
3923 OPENSSL_EXPORT int SSL_early_callback_ctx_extension_get(
3924     const SSL_CLIENT_HELLO *client_hello, uint16_t extension_type,
3925     const uint8_t **out_data, size_t *out_len);
3926 
3927 // SSL_CTX_set_select_certificate_cb sets a callback that is called before most
3928 // ClientHello processing and before the decision whether to resume a session
3929 // is made. The callback may inspect the ClientHello and configure the
3930 // connection. See |ssl_select_cert_result_t| for details of the return values.
3931 //
3932 // In the case that a retry is indicated, |SSL_get_error| will return
3933 // |SSL_ERROR_PENDING_CERTIFICATE| and the caller should arrange for the
3934 // high-level operation on |ssl| to be retried at a later time, which will
3935 // result in another call to |cb|.
3936 //
3937 // |SSL_get_servername| may be used during this callback.
3938 //
3939 // Note: The |SSL_CLIENT_HELLO| is only valid for the duration of the callback
3940 // and is not valid while the handshake is paused.
3941 OPENSSL_EXPORT void SSL_CTX_set_select_certificate_cb(
3942     SSL_CTX *ctx,
3943     enum ssl_select_cert_result_t (*cb)(const SSL_CLIENT_HELLO *));
3944 
3945 // SSL_CTX_set_dos_protection_cb sets a callback that is called once the
3946 // resumption decision for a ClientHello has been made. It can return one to
3947 // allow the handshake to continue or zero to cause the handshake to abort.
3948 OPENSSL_EXPORT void SSL_CTX_set_dos_protection_cb(
3949     SSL_CTX *ctx, int (*cb)(const SSL_CLIENT_HELLO *));
3950 
3951 // SSL_CTX_set_reverify_on_resume configures whether the certificate
3952 // verification callback will be used to reverify stored certificates
3953 // when resuming a session. This only works with |SSL_CTX_set_custom_verify|.
3954 // For now, this is incompatible with |SSL_VERIFY_NONE| mode, and is only
3955 // respected on clients.
3956 OPENSSL_EXPORT void SSL_CTX_set_reverify_on_resume(SSL_CTX *ctx, int enabled);
3957 
3958 // SSL_set_enforce_rsa_key_usage configures whether the keyUsage extension of
3959 // RSA leaf certificates will be checked for consistency with the TLS
3960 // usage. This parameter may be set late; it will not be read until after the
3961 // certificate verification callback.
3962 OPENSSL_EXPORT void SSL_set_enforce_rsa_key_usage(SSL *ssl, int enabled);
3963 
3964 // SSL_ST_* are possible values for |SSL_state|, the bitmasks that make them up,
3965 // and some historical values for compatibility. Only |SSL_ST_INIT| and
3966 // |SSL_ST_OK| are ever returned.
3967 #define SSL_ST_CONNECT 0x1000
3968 #define SSL_ST_ACCEPT 0x2000
3969 #define SSL_ST_MASK 0x0FFF
3970 #define SSL_ST_INIT (SSL_ST_CONNECT | SSL_ST_ACCEPT)
3971 #define SSL_ST_OK 0x03
3972 #define SSL_ST_RENEGOTIATE (0x04 | SSL_ST_INIT)
3973 #define SSL_ST_BEFORE (0x05 | SSL_ST_INIT)
3974 
3975 // TLS_ST_* are aliases for |SSL_ST_*| for OpenSSL 1.1.0 compatibility.
3976 #define TLS_ST_OK SSL_ST_OK
3977 #define TLS_ST_BEFORE SSL_ST_BEFORE
3978 
3979 // SSL_CB_* are possible values for the |type| parameter in the info
3980 // callback and the bitmasks that make them up.
3981 #define SSL_CB_LOOP 0x01
3982 #define SSL_CB_EXIT 0x02
3983 #define SSL_CB_READ 0x04
3984 #define SSL_CB_WRITE 0x08
3985 #define SSL_CB_ALERT 0x4000
3986 #define SSL_CB_READ_ALERT (SSL_CB_ALERT | SSL_CB_READ)
3987 #define SSL_CB_WRITE_ALERT (SSL_CB_ALERT | SSL_CB_WRITE)
3988 #define SSL_CB_ACCEPT_LOOP (SSL_ST_ACCEPT | SSL_CB_LOOP)
3989 #define SSL_CB_ACCEPT_EXIT (SSL_ST_ACCEPT | SSL_CB_EXIT)
3990 #define SSL_CB_CONNECT_LOOP (SSL_ST_CONNECT | SSL_CB_LOOP)
3991 #define SSL_CB_CONNECT_EXIT (SSL_ST_CONNECT | SSL_CB_EXIT)
3992 #define SSL_CB_HANDSHAKE_START 0x10
3993 #define SSL_CB_HANDSHAKE_DONE 0x20
3994 
3995 // SSL_CTX_set_info_callback configures a callback to be run when various
3996 // events occur during a connection's lifetime. The |type| argument determines
3997 // the type of event and the meaning of the |value| argument. Callbacks must
3998 // ignore unexpected |type| values.
3999 //
4000 // |SSL_CB_READ_ALERT| is signaled for each alert received, warning or fatal.
4001 // The |value| argument is a 16-bit value where the alert level (either
4002 // |SSL3_AL_WARNING| or |SSL3_AL_FATAL|) is in the most-significant eight bits
4003 // and the alert type (one of |SSL_AD_*|) is in the least-significant eight.
4004 //
4005 // |SSL_CB_WRITE_ALERT| is signaled for each alert sent. The |value| argument
4006 // is constructed as with |SSL_CB_READ_ALERT|.
4007 //
4008 // |SSL_CB_HANDSHAKE_START| is signaled when a handshake begins. The |value|
4009 // argument is always one.
4010 //
4011 // |SSL_CB_HANDSHAKE_DONE| is signaled when a handshake completes successfully.
4012 // The |value| argument is always one. If a handshake False Starts, this event
4013 // may be used to determine when the Finished message is received.
4014 //
4015 // The following event types expose implementation details of the handshake
4016 // state machine. Consuming them is deprecated.
4017 //
4018 // |SSL_CB_ACCEPT_LOOP| (respectively, |SSL_CB_CONNECT_LOOP|) is signaled when
4019 // a server (respectively, client) handshake progresses. The |value| argument
4020 // is always one.
4021 //
4022 // |SSL_CB_ACCEPT_EXIT| (respectively, |SSL_CB_CONNECT_EXIT|) is signaled when
4023 // a server (respectively, client) handshake completes, fails, or is paused.
4024 // The |value| argument is one if the handshake succeeded and <= 0
4025 // otherwise.
4026 OPENSSL_EXPORT void SSL_CTX_set_info_callback(
4027     SSL_CTX *ctx, void (*cb)(const SSL *ssl, int type, int value));
4028 
4029 // SSL_CTX_get_info_callback returns the callback set by
4030 // |SSL_CTX_set_info_callback|.
4031 OPENSSL_EXPORT void (*SSL_CTX_get_info_callback(SSL_CTX *ctx))(const SSL *ssl,
4032                                                                int type,
4033                                                                int value);
4034 
4035 // SSL_set_info_callback configures a callback to be run at various events
4036 // during a connection's lifetime. See |SSL_CTX_set_info_callback|.
4037 OPENSSL_EXPORT void SSL_set_info_callback(
4038     SSL *ssl, void (*cb)(const SSL *ssl, int type, int value));
4039 
4040 // SSL_get_info_callback returns the callback set by |SSL_set_info_callback|.
4041 OPENSSL_EXPORT void (*SSL_get_info_callback(const SSL *ssl))(const SSL *ssl,
4042                                                              int type,
4043                                                              int value);
4044 
4045 // SSL_state_string_long returns the current state of the handshake state
4046 // machine as a string. This may be useful for debugging and logging.
4047 OPENSSL_EXPORT const char *SSL_state_string_long(const SSL *ssl);
4048 
4049 #define SSL_SENT_SHUTDOWN 1
4050 #define SSL_RECEIVED_SHUTDOWN 2
4051 
4052 // SSL_get_shutdown returns a bitmask with a subset of |SSL_SENT_SHUTDOWN| and
4053 // |SSL_RECEIVED_SHUTDOWN| to query whether close_notify was sent or received,
4054 // respectively.
4055 OPENSSL_EXPORT int SSL_get_shutdown(const SSL *ssl);
4056 
4057 // SSL_get_peer_signature_algorithm returns the signature algorithm used by the
4058 // peer. If not applicable, it returns zero.
4059 OPENSSL_EXPORT uint16_t SSL_get_peer_signature_algorithm(const SSL *ssl);
4060 
4061 // SSL_get_client_random writes up to |max_out| bytes of the most recent
4062 // handshake's client_random to |out| and returns the number of bytes written.
4063 // If |max_out| is zero, it returns the size of the client_random.
4064 OPENSSL_EXPORT size_t SSL_get_client_random(const SSL *ssl, uint8_t *out,
4065                                             size_t max_out);
4066 
4067 // SSL_get_server_random writes up to |max_out| bytes of the most recent
4068 // handshake's server_random to |out| and returns the number of bytes written.
4069 // If |max_out| is zero, it returns the size of the server_random.
4070 OPENSSL_EXPORT size_t SSL_get_server_random(const SSL *ssl, uint8_t *out,
4071                                             size_t max_out);
4072 
4073 // SSL_get_pending_cipher returns the cipher suite for the current handshake or
4074 // NULL if one has not been negotiated yet or there is no pending handshake.
4075 OPENSSL_EXPORT const SSL_CIPHER *SSL_get_pending_cipher(const SSL *ssl);
4076 
4077 // SSL_set_retain_only_sha256_of_client_certs, on a server, sets whether only
4078 // the SHA-256 hash of peer's certificate should be saved in memory and in the
4079 // session. This can save memory, ticket size and session cache space. If
4080 // enabled, |SSL_get_peer_certificate| will return NULL after the handshake
4081 // completes. See |SSL_SESSION_has_peer_sha256| and
4082 // |SSL_SESSION_get0_peer_sha256| to query the hash.
4083 OPENSSL_EXPORT void SSL_set_retain_only_sha256_of_client_certs(SSL *ssl,
4084                                                                int enable);
4085 
4086 // SSL_CTX_set_retain_only_sha256_of_client_certs, on a server, sets whether
4087 // only the SHA-256 hash of peer's certificate should be saved in memory and in
4088 // the session. This can save memory, ticket size and session cache space. If
4089 // enabled, |SSL_get_peer_certificate| will return NULL after the handshake
4090 // completes. See |SSL_SESSION_has_peer_sha256| and
4091 // |SSL_SESSION_get0_peer_sha256| to query the hash.
4092 OPENSSL_EXPORT void SSL_CTX_set_retain_only_sha256_of_client_certs(SSL_CTX *ctx,
4093                                                                    int enable);
4094 
4095 // SSL_CTX_set_grease_enabled configures whether sockets on |ctx| should enable
4096 // GREASE. See draft-davidben-tls-grease-01.
4097 OPENSSL_EXPORT void SSL_CTX_set_grease_enabled(SSL_CTX *ctx, int enabled);
4098 
4099 // SSL_max_seal_overhead returns the maximum overhead, in bytes, of sealing a
4100 // record with |ssl|.
4101 OPENSSL_EXPORT size_t SSL_max_seal_overhead(const SSL *ssl);
4102 
4103 // SSL_CTX_set_false_start_allowed_without_alpn configures whether connections
4104 // on |ctx| may use False Start (if |SSL_MODE_ENABLE_FALSE_START| is enabled)
4105 // without negotiating ALPN.
4106 OPENSSL_EXPORT void SSL_CTX_set_false_start_allowed_without_alpn(SSL_CTX *ctx,
4107                                                                  int allowed);
4108 
4109 // SSL_used_hello_retry_request returns one if the TLS 1.3 HelloRetryRequest
4110 // message has been either sent by the server or received by the client. It
4111 // returns zero otherwise.
4112 OPENSSL_EXPORT int SSL_used_hello_retry_request(const SSL *ssl);
4113 
4114 // SSL_set_jdk11_workaround configures whether to workaround various bugs in
4115 // JDK 11's TLS 1.3 implementation by disabling TLS 1.3 for such clients.
4116 //
4117 // https://bugs.openjdk.java.net/browse/JDK-8211806
4118 // https://bugs.openjdk.java.net/browse/JDK-8212885
4119 // https://bugs.openjdk.java.net/browse/JDK-8213202
4120 OPENSSL_EXPORT void SSL_set_jdk11_workaround(SSL *ssl, int enable);
4121 
4122 
4123 // Deprecated functions.
4124 
4125 // SSL_library_init calls |CRYPTO_library_init| and returns one.
4126 OPENSSL_EXPORT int SSL_library_init(void);
4127 
4128 // SSL_CIPHER_description writes a description of |cipher| into |buf| and
4129 // returns |buf|. If |buf| is NULL, it returns a newly allocated string, to be
4130 // freed with |OPENSSL_free|, or NULL on error.
4131 //
4132 // The description includes a trailing newline and has the form:
4133 // AES128-SHA              Kx=RSA      Au=RSA  Enc=AES(128)  Mac=SHA1
4134 //
4135 // Consider |SSL_CIPHER_standard_name| or |SSL_CIPHER_get_name| instead.
4136 OPENSSL_EXPORT const char *SSL_CIPHER_description(const SSL_CIPHER *cipher,
4137                                                   char *buf, int len);
4138 
4139 // SSL_CIPHER_get_version returns the string "TLSv1/SSLv3".
4140 OPENSSL_EXPORT const char *SSL_CIPHER_get_version(const SSL_CIPHER *cipher);
4141 
4142 // SSL_CIPHER_get_rfc_name returns a newly-allocated string containing the
4143 // result of |SSL_CIPHER_standard_name| or NULL on error. The caller is
4144 // responsible for calling |OPENSSL_free| on the result.
4145 //
4146 // Use |SSL_CIPHER_standard_name| instead.
4147 OPENSSL_EXPORT char *SSL_CIPHER_get_rfc_name(const SSL_CIPHER *cipher);
4148 
4149 typedef void COMP_METHOD;
4150 typedef struct ssl_comp_st SSL_COMP;
4151 
4152 // SSL_COMP_get_compression_methods returns NULL.
4153 OPENSSL_EXPORT STACK_OF(SSL_COMP) *SSL_COMP_get_compression_methods(void);
4154 
4155 // SSL_COMP_add_compression_method returns one.
4156 OPENSSL_EXPORT int SSL_COMP_add_compression_method(int id, COMP_METHOD *cm);
4157 
4158 // SSL_COMP_get_name returns NULL.
4159 OPENSSL_EXPORT const char *SSL_COMP_get_name(const COMP_METHOD *comp);
4160 
4161 // SSL_COMP_get0_name returns the |name| member of |comp|.
4162 OPENSSL_EXPORT const char *SSL_COMP_get0_name(const SSL_COMP *comp);
4163 
4164 // SSL_COMP_get_id returns the |id| member of |comp|.
4165 OPENSSL_EXPORT int SSL_COMP_get_id(const SSL_COMP *comp);
4166 
4167 // SSL_COMP_free_compression_methods does nothing.
4168 OPENSSL_EXPORT void SSL_COMP_free_compression_methods(void);
4169 
4170 // SSLv23_method calls |TLS_method|.
4171 OPENSSL_EXPORT const SSL_METHOD *SSLv23_method(void);
4172 
4173 // These version-specific methods behave exactly like |TLS_method| and
4174 // |DTLS_method| except they also call |SSL_CTX_set_min_proto_version| and
4175 // |SSL_CTX_set_max_proto_version| to lock connections to that protocol
4176 // version.
4177 OPENSSL_EXPORT const SSL_METHOD *TLSv1_method(void);
4178 OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_method(void);
4179 OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_method(void);
4180 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_method(void);
4181 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_method(void);
4182 
4183 // These client- and server-specific methods call their corresponding generic
4184 // methods.
4185 OPENSSL_EXPORT const SSL_METHOD *TLS_server_method(void);
4186 OPENSSL_EXPORT const SSL_METHOD *TLS_client_method(void);
4187 OPENSSL_EXPORT const SSL_METHOD *SSLv23_server_method(void);
4188 OPENSSL_EXPORT const SSL_METHOD *SSLv23_client_method(void);
4189 OPENSSL_EXPORT const SSL_METHOD *TLSv1_server_method(void);
4190 OPENSSL_EXPORT const SSL_METHOD *TLSv1_client_method(void);
4191 OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_server_method(void);
4192 OPENSSL_EXPORT const SSL_METHOD *TLSv1_1_client_method(void);
4193 OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_server_method(void);
4194 OPENSSL_EXPORT const SSL_METHOD *TLSv1_2_client_method(void);
4195 OPENSSL_EXPORT const SSL_METHOD *DTLS_server_method(void);
4196 OPENSSL_EXPORT const SSL_METHOD *DTLS_client_method(void);
4197 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_server_method(void);
4198 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_client_method(void);
4199 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_server_method(void);
4200 OPENSSL_EXPORT const SSL_METHOD *DTLSv1_2_client_method(void);
4201 
4202 // SSL_clear resets |ssl| to allow another connection and returns one on success
4203 // or zero on failure. It returns most configuration state but releases memory
4204 // associated with the current connection.
4205 //
4206 // Free |ssl| and create a new one instead.
4207 OPENSSL_EXPORT int SSL_clear(SSL *ssl);
4208 
4209 // SSL_CTX_set_tmp_rsa_callback does nothing.
4210 OPENSSL_EXPORT void SSL_CTX_set_tmp_rsa_callback(
4211     SSL_CTX *ctx, RSA *(*cb)(SSL *ssl, int is_export, int keylength));
4212 
4213 // SSL_set_tmp_rsa_callback does nothing.
4214 OPENSSL_EXPORT void SSL_set_tmp_rsa_callback(SSL *ssl,
4215                                              RSA *(*cb)(SSL *ssl, int is_export,
4216                                                         int keylength));
4217 
4218 // SSL_CTX_sess_connect returns zero.
4219 OPENSSL_EXPORT int SSL_CTX_sess_connect(const SSL_CTX *ctx);
4220 
4221 // SSL_CTX_sess_connect_good returns zero.
4222 OPENSSL_EXPORT int SSL_CTX_sess_connect_good(const SSL_CTX *ctx);
4223 
4224 // SSL_CTX_sess_connect_renegotiate returns zero.
4225 OPENSSL_EXPORT int SSL_CTX_sess_connect_renegotiate(const SSL_CTX *ctx);
4226 
4227 // SSL_CTX_sess_accept returns zero.
4228 OPENSSL_EXPORT int SSL_CTX_sess_accept(const SSL_CTX *ctx);
4229 
4230 // SSL_CTX_sess_accept_renegotiate returns zero.
4231 OPENSSL_EXPORT int SSL_CTX_sess_accept_renegotiate(const SSL_CTX *ctx);
4232 
4233 // SSL_CTX_sess_accept_good returns zero.
4234 OPENSSL_EXPORT int SSL_CTX_sess_accept_good(const SSL_CTX *ctx);
4235 
4236 // SSL_CTX_sess_hits returns zero.
4237 OPENSSL_EXPORT int SSL_CTX_sess_hits(const SSL_CTX *ctx);
4238 
4239 // SSL_CTX_sess_cb_hits returns zero.
4240 OPENSSL_EXPORT int SSL_CTX_sess_cb_hits(const SSL_CTX *ctx);
4241 
4242 // SSL_CTX_sess_misses returns zero.
4243 OPENSSL_EXPORT int SSL_CTX_sess_misses(const SSL_CTX *ctx);
4244 
4245 // SSL_CTX_sess_timeouts returns zero.
4246 OPENSSL_EXPORT int SSL_CTX_sess_timeouts(const SSL_CTX *ctx);
4247 
4248 // SSL_CTX_sess_cache_full returns zero.
4249 OPENSSL_EXPORT int SSL_CTX_sess_cache_full(const SSL_CTX *ctx);
4250 
4251 // SSL_cutthrough_complete calls |SSL_in_false_start|.
4252 OPENSSL_EXPORT int SSL_cutthrough_complete(const SSL *ssl);
4253 
4254 // SSL_num_renegotiations calls |SSL_total_renegotiations|.
4255 OPENSSL_EXPORT int SSL_num_renegotiations(const SSL *ssl);
4256 
4257 // SSL_CTX_need_tmp_RSA returns zero.
4258 OPENSSL_EXPORT int SSL_CTX_need_tmp_RSA(const SSL_CTX *ctx);
4259 
4260 // SSL_need_tmp_RSA returns zero.
4261 OPENSSL_EXPORT int SSL_need_tmp_RSA(const SSL *ssl);
4262 
4263 // SSL_CTX_set_tmp_rsa returns one.
4264 OPENSSL_EXPORT int SSL_CTX_set_tmp_rsa(SSL_CTX *ctx, const RSA *rsa);
4265 
4266 // SSL_set_tmp_rsa returns one.
4267 OPENSSL_EXPORT int SSL_set_tmp_rsa(SSL *ssl, const RSA *rsa);
4268 
4269 // SSL_CTX_get_read_ahead returns zero.
4270 OPENSSL_EXPORT int SSL_CTX_get_read_ahead(const SSL_CTX *ctx);
4271 
4272 // SSL_CTX_set_read_ahead returns one.
4273 OPENSSL_EXPORT int SSL_CTX_set_read_ahead(SSL_CTX *ctx, int yes);
4274 
4275 // SSL_get_read_ahead returns zero.
4276 OPENSSL_EXPORT int SSL_get_read_ahead(const SSL *ssl);
4277 
4278 // SSL_set_read_ahead returns one.
4279 OPENSSL_EXPORT int SSL_set_read_ahead(SSL *ssl, int yes);
4280 
4281 // SSL_set_state does nothing.
4282 OPENSSL_EXPORT void SSL_set_state(SSL *ssl, int state);
4283 
4284 // SSL_get_shared_ciphers writes an empty string to |buf| and returns a
4285 // pointer to |buf|, or NULL if |len| is less than or equal to zero.
4286 OPENSSL_EXPORT char *SSL_get_shared_ciphers(const SSL *ssl, char *buf, int len);
4287 
4288 // SSL_get_shared_sigalgs returns zero.
4289 OPENSSL_EXPORT int SSL_get_shared_sigalgs(SSL *ssl, int idx, int *psign,
4290                                           int *phash, int *psignandhash,
4291                                           uint8_t *rsig, uint8_t *rhash);
4292 
4293 // SSL_MODE_HANDSHAKE_CUTTHROUGH is the same as SSL_MODE_ENABLE_FALSE_START.
4294 #define SSL_MODE_HANDSHAKE_CUTTHROUGH SSL_MODE_ENABLE_FALSE_START
4295 
4296 // i2d_SSL_SESSION serializes |in| to the bytes pointed to by |*pp|. On success,
4297 // it returns the number of bytes written and advances |*pp| by that many bytes.
4298 // On failure, it returns -1. If |pp| is NULL, no bytes are written and only the
4299 // length is returned.
4300 //
4301 // Use |SSL_SESSION_to_bytes| instead.
4302 OPENSSL_EXPORT int i2d_SSL_SESSION(SSL_SESSION *in, uint8_t **pp);
4303 
4304 // d2i_SSL_SESSION parses a serialized session from the |length| bytes pointed
4305 // to by |*pp|. It returns the new |SSL_SESSION| and advances |*pp| by the
4306 // number of bytes consumed on success and NULL on failure. The caller takes
4307 // ownership of the new session and must call |SSL_SESSION_free| when done.
4308 //
4309 // If |a| is non-NULL, |*a| is released and set the new |SSL_SESSION|.
4310 //
4311 // Use |SSL_SESSION_from_bytes| instead.
4312 OPENSSL_EXPORT SSL_SESSION *d2i_SSL_SESSION(SSL_SESSION **a, const uint8_t **pp,
4313                                             long length);
4314 
4315 // i2d_SSL_SESSION_bio serializes |session| and writes the result to |bio|. It
4316 // returns the number of bytes written on success and <= 0 on error.
4317 OPENSSL_EXPORT int i2d_SSL_SESSION_bio(BIO *bio, const SSL_SESSION *session);
4318 
4319 // d2i_SSL_SESSION_bio reads a serialized |SSL_SESSION| from |bio| and returns a
4320 // newly-allocated |SSL_SESSION| or NULL on error. If |out| is not NULL, it also
4321 // frees |*out| and sets |*out| to the new |SSL_SESSION|.
4322 OPENSSL_EXPORT SSL_SESSION *d2i_SSL_SESSION_bio(BIO *bio, SSL_SESSION **out);
4323 
4324 // ERR_load_SSL_strings does nothing.
4325 OPENSSL_EXPORT void ERR_load_SSL_strings(void);
4326 
4327 // SSL_load_error_strings does nothing.
4328 OPENSSL_EXPORT void SSL_load_error_strings(void);
4329 
4330 // SSL_CTX_set_tlsext_use_srtp calls |SSL_CTX_set_srtp_profiles|. It returns
4331 // zero on success and one on failure.
4332 //
4333 // WARNING: this function is dangerous because it breaks the usual return value
4334 // convention. Use |SSL_CTX_set_srtp_profiles| instead.
4335 OPENSSL_EXPORT int SSL_CTX_set_tlsext_use_srtp(SSL_CTX *ctx,
4336                                                const char *profiles);
4337 
4338 // SSL_set_tlsext_use_srtp calls |SSL_set_srtp_profiles|. It returns zero on
4339 // success and one on failure.
4340 //
4341 // WARNING: this function is dangerous because it breaks the usual return value
4342 // convention. Use |SSL_set_srtp_profiles| instead.
4343 OPENSSL_EXPORT int SSL_set_tlsext_use_srtp(SSL *ssl, const char *profiles);
4344 
4345 // SSL_get_current_compression returns NULL.
4346 OPENSSL_EXPORT const COMP_METHOD *SSL_get_current_compression(SSL *ssl);
4347 
4348 // SSL_get_current_expansion returns NULL.
4349 OPENSSL_EXPORT const COMP_METHOD *SSL_get_current_expansion(SSL *ssl);
4350 
4351 // SSL_get_server_tmp_key returns zero.
4352 OPENSSL_EXPORT int SSL_get_server_tmp_key(SSL *ssl, EVP_PKEY **out_key);
4353 
4354 // SSL_CTX_set_tmp_dh returns 1.
4355 OPENSSL_EXPORT int SSL_CTX_set_tmp_dh(SSL_CTX *ctx, const DH *dh);
4356 
4357 // SSL_set_tmp_dh returns 1.
4358 OPENSSL_EXPORT int SSL_set_tmp_dh(SSL *ssl, const DH *dh);
4359 
4360 // SSL_CTX_set_tmp_dh_callback does nothing.
4361 OPENSSL_EXPORT void SSL_CTX_set_tmp_dh_callback(
4362     SSL_CTX *ctx, DH *(*cb)(SSL *ssl, int is_export, int keylength));
4363 
4364 // SSL_set_tmp_dh_callback does nothing.
4365 OPENSSL_EXPORT void SSL_set_tmp_dh_callback(SSL *ssl,
4366                                             DH *(*cb)(SSL *ssl, int is_export,
4367                                                       int keylength));
4368 
4369 // SSL_CTX_set1_sigalgs takes |num_values| ints and interprets them as pairs
4370 // where the first is the nid of a hash function and the second is an
4371 // |EVP_PKEY_*| value. It configures the signature algorithm preferences for
4372 // |ctx| based on them and returns one on success or zero on error.
4373 //
4374 // This API is compatible with OpenSSL. However, BoringSSL-specific code should
4375 // prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
4376 // more convenient to codesearch for specific algorithm values.
4377 OPENSSL_EXPORT int SSL_CTX_set1_sigalgs(SSL_CTX *ctx, const int *values,
4378                                         size_t num_values);
4379 
4380 // SSL_set1_sigalgs takes |num_values| ints and interprets them as pairs where
4381 // the first is the nid of a hash function and the second is an |EVP_PKEY_*|
4382 // value. It configures the signature algorithm preferences for |ssl| based on
4383 // them and returns one on success or zero on error.
4384 //
4385 // This API is compatible with OpenSSL. However, BoringSSL-specific code should
4386 // prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
4387 // more convenient to codesearch for specific algorithm values.
4388 OPENSSL_EXPORT int SSL_set1_sigalgs(SSL *ssl, const int *values,
4389                                     size_t num_values);
4390 
4391 // SSL_CTX_set1_sigalgs_list takes a textual specification of a set of signature
4392 // algorithms and configures them on |ctx|. It returns one on success and zero
4393 // on error. See
4394 // https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_set1_sigalgs_list.html for
4395 // a description of the text format. Also note that TLS 1.3 names (e.g.
4396 // "rsa_pkcs1_md5_sha1") can also be used (as in OpenSSL, although OpenSSL
4397 // doesn't document that).
4398 //
4399 // This API is compatible with OpenSSL. However, BoringSSL-specific code should
4400 // prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
4401 // more convenient to codesearch for specific algorithm values.
4402 OPENSSL_EXPORT int SSL_CTX_set1_sigalgs_list(SSL_CTX *ctx, const char *str);
4403 
4404 // SSL_set1_sigalgs_list takes a textual specification of a set of signature
4405 // algorithms and configures them on |ssl|. It returns one on success and zero
4406 // on error. See
4407 // https://www.openssl.org/docs/man1.1.0/man3/SSL_CTX_set1_sigalgs_list.html for
4408 // a description of the text format. Also note that TLS 1.3 names (e.g.
4409 // "rsa_pkcs1_md5_sha1") can also be used (as in OpenSSL, although OpenSSL
4410 // doesn't document that).
4411 //
4412 // This API is compatible with OpenSSL. However, BoringSSL-specific code should
4413 // prefer |SSL_CTX_set_signing_algorithm_prefs| because it's clearer and it's
4414 // more convenient to codesearch for specific algorithm values.
4415 OPENSSL_EXPORT int SSL_set1_sigalgs_list(SSL *ssl, const char *str);
4416 
4417 #define SSL_set_app_data(s, arg) (SSL_set_ex_data(s, 0, (char *)(arg)))
4418 #define SSL_get_app_data(s) (SSL_get_ex_data(s, 0))
4419 #define SSL_SESSION_set_app_data(s, a) \
4420   (SSL_SESSION_set_ex_data(s, 0, (char *)(a)))
4421 #define SSL_SESSION_get_app_data(s) (SSL_SESSION_get_ex_data(s, 0))
4422 #define SSL_CTX_get_app_data(ctx) (SSL_CTX_get_ex_data(ctx, 0))
4423 #define SSL_CTX_set_app_data(ctx, arg) \
4424   (SSL_CTX_set_ex_data(ctx, 0, (char *)(arg)))
4425 
4426 #define OpenSSL_add_ssl_algorithms() SSL_library_init()
4427 #define SSLeay_add_ssl_algorithms() SSL_library_init()
4428 
4429 #define SSL_get_cipher(ssl) SSL_CIPHER_get_name(SSL_get_current_cipher(ssl))
4430 #define SSL_get_cipher_bits(ssl, out_alg_bits) \
4431     SSL_CIPHER_get_bits(SSL_get_current_cipher(ssl), out_alg_bits)
4432 #define SSL_get_cipher_version(ssl) \
4433     SSL_CIPHER_get_version(SSL_get_current_cipher(ssl))
4434 #define SSL_get_cipher_name(ssl) \
4435     SSL_CIPHER_get_name(SSL_get_current_cipher(ssl))
4436 #define SSL_get_time(session) SSL_SESSION_get_time(session)
4437 #define SSL_set_time(session, time) SSL_SESSION_set_time((session), (time))
4438 #define SSL_get_timeout(session) SSL_SESSION_get_timeout(session)
4439 #define SSL_set_timeout(session, timeout) \
4440     SSL_SESSION_set_timeout((session), (timeout))
4441 
4442 struct ssl_comp_st {
4443   int id;
4444   const char *name;
4445   char *method;
4446 };
4447 
4448 DEFINE_STACK_OF(SSL_COMP)
4449 
4450 // The following flags do nothing and are included only to make it easier to
4451 // compile code with BoringSSL.
4452 #define SSL_MODE_AUTO_RETRY 0
4453 #define SSL_MODE_RELEASE_BUFFERS 0
4454 #define SSL_MODE_SEND_CLIENTHELLO_TIME 0
4455 #define SSL_MODE_SEND_SERVERHELLO_TIME 0
4456 #define SSL_OP_ALL 0
4457 #define SSL_OP_ALLOW_UNSAFE_LEGACY_RENEGOTIATION 0
4458 #define SSL_OP_DONT_INSERT_EMPTY_FRAGMENTS 0
4459 #define SSL_OP_EPHEMERAL_RSA 0
4460 #define SSL_OP_LEGACY_SERVER_CONNECT 0
4461 #define SSL_OP_MICROSOFT_BIG_SSLV3_BUFFER 0
4462 #define SSL_OP_MICROSOFT_SESS_ID_BUG 0
4463 #define SSL_OP_MSIE_SSLV2_RSA_PADDING 0
4464 #define SSL_OP_NETSCAPE_CA_DN_BUG 0
4465 #define SSL_OP_NETSCAPE_CHALLENGE_BUG 0
4466 #define SSL_OP_NETSCAPE_DEMO_CIPHER_CHANGE_BUG 0
4467 #define SSL_OP_NETSCAPE_REUSE_CIPHER_CHANGE_BUG 0
4468 #define SSL_OP_NO_COMPRESSION 0
4469 #define SSL_OP_NO_RENEGOTIATION 0  // ssl_renegotiate_never is the default
4470 #define SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION 0
4471 #define SSL_OP_NO_SSLv2 0
4472 #define SSL_OP_NO_SSLv3 0
4473 #define SSL_OP_PKCS1_CHECK_1 0
4474 #define SSL_OP_PKCS1_CHECK_2 0
4475 #define SSL_OP_SINGLE_DH_USE 0
4476 #define SSL_OP_SINGLE_ECDH_USE 0
4477 #define SSL_OP_SSLEAY_080_CLIENT_DH_BUG 0
4478 #define SSL_OP_SSLREF2_REUSE_CERT_TYPE_BUG 0
4479 #define SSL_OP_TLS_BLOCK_PADDING_BUG 0
4480 #define SSL_OP_TLS_D5_BUG 0
4481 #define SSL_OP_TLS_ROLLBACK_BUG 0
4482 #define SSL_VERIFY_CLIENT_ONCE 0
4483 
4484 // SSL_cache_hit calls |SSL_session_reused|.
4485 OPENSSL_EXPORT int SSL_cache_hit(SSL *ssl);
4486 
4487 // SSL_get_default_timeout returns |SSL_DEFAULT_SESSION_TIMEOUT|.
4488 OPENSSL_EXPORT long SSL_get_default_timeout(const SSL *ssl);
4489 
4490 // SSL_get_version returns a string describing the TLS version used by |ssl|.
4491 // For example, "TLSv1.2" or "DTLSv1".
4492 OPENSSL_EXPORT const char *SSL_get_version(const SSL *ssl);
4493 
4494 // SSL_get_cipher_list returns the name of the |n|th cipher in the output of
4495 // |SSL_get_ciphers| or NULL if out of range. Use |SSL_get_ciphers| instead.
4496 OPENSSL_EXPORT const char *SSL_get_cipher_list(const SSL *ssl, int n);
4497 
4498 // SSL_CTX_set_client_cert_cb sets a callback which is called on the client if
4499 // the server requests a client certificate and none is configured. On success,
4500 // the callback should return one and set |*out_x509| to |*out_pkey| to a leaf
4501 // certificate and private key, respectively, passing ownership. It should
4502 // return zero to send no certificate and -1 to fail or pause the handshake. If
4503 // the handshake is paused, |SSL_get_error| will return
4504 // |SSL_ERROR_WANT_X509_LOOKUP|.
4505 //
4506 // The callback may call |SSL_get0_certificate_types| and
4507 // |SSL_get_client_CA_list| for information on the server's certificate request.
4508 //
4509 // Use |SSL_CTX_set_cert_cb| instead. Configuring intermediate certificates with
4510 // this function is confusing. This callback may not be registered concurrently
4511 // with |SSL_CTX_set_cert_cb| or |SSL_set_cert_cb|.
4512 OPENSSL_EXPORT void SSL_CTX_set_client_cert_cb(
4513     SSL_CTX *ctx, int (*cb)(SSL *ssl, X509 **out_x509, EVP_PKEY **out_pkey));
4514 
4515 #define SSL_NOTHING SSL_ERROR_NONE
4516 #define SSL_WRITING SSL_ERROR_WANT_WRITE
4517 #define SSL_READING SSL_ERROR_WANT_READ
4518 
4519 // SSL_want returns one of the above values to determine what the most recent
4520 // operation on |ssl| was blocked on. Use |SSL_get_error| instead.
4521 OPENSSL_EXPORT int SSL_want(const SSL *ssl);
4522 
4523 #define SSL_want_read(ssl) (SSL_want(ssl) == SSL_READING)
4524 #define SSL_want_write(ssl) (SSL_want(ssl) == SSL_WRITING)
4525 
4526  // SSL_get_finished writes up to |count| bytes of the Finished message sent by
4527  // |ssl| to |buf|. It returns the total untruncated length or zero if none has
4528  // been sent yet. At TLS 1.3 and later, it returns zero.
4529  //
4530  // Use |SSL_get_tls_unique| instead.
4531 OPENSSL_EXPORT size_t SSL_get_finished(const SSL *ssl, void *buf, size_t count);
4532 
4533  // SSL_get_peer_finished writes up to |count| bytes of the Finished message
4534  // received from |ssl|'s peer to |buf|. It returns the total untruncated length
4535  // or zero if none has been received yet. At TLS 1.3 and later, it returns
4536  // zero.
4537  //
4538  // Use |SSL_get_tls_unique| instead.
4539 OPENSSL_EXPORT size_t SSL_get_peer_finished(const SSL *ssl, void *buf,
4540                                             size_t count);
4541 
4542 // SSL_alert_type_string returns "!". Use |SSL_alert_type_string_long|
4543 // instead.
4544 OPENSSL_EXPORT const char *SSL_alert_type_string(int value);
4545 
4546 // SSL_alert_desc_string returns "!!". Use |SSL_alert_desc_string_long|
4547 // instead.
4548 OPENSSL_EXPORT const char *SSL_alert_desc_string(int value);
4549 
4550 // SSL_state_string returns "!!!!!!". Use |SSL_state_string_long| for a more
4551 // intelligible string.
4552 OPENSSL_EXPORT const char *SSL_state_string(const SSL *ssl);
4553 
4554 // SSL_TXT_* expand to strings.
4555 #define SSL_TXT_MEDIUM "MEDIUM"
4556 #define SSL_TXT_HIGH "HIGH"
4557 #define SSL_TXT_FIPS "FIPS"
4558 #define SSL_TXT_kRSA "kRSA"
4559 #define SSL_TXT_kDHE "kDHE"
4560 #define SSL_TXT_kEDH "kEDH"
4561 #define SSL_TXT_kECDHE "kECDHE"
4562 #define SSL_TXT_kEECDH "kEECDH"
4563 #define SSL_TXT_kPSK "kPSK"
4564 #define SSL_TXT_aRSA "aRSA"
4565 #define SSL_TXT_aECDSA "aECDSA"
4566 #define SSL_TXT_aPSK "aPSK"
4567 #define SSL_TXT_DH "DH"
4568 #define SSL_TXT_DHE "DHE"
4569 #define SSL_TXT_EDH "EDH"
4570 #define SSL_TXT_RSA "RSA"
4571 #define SSL_TXT_ECDH "ECDH"
4572 #define SSL_TXT_ECDHE "ECDHE"
4573 #define SSL_TXT_EECDH "EECDH"
4574 #define SSL_TXT_ECDSA "ECDSA"
4575 #define SSL_TXT_PSK "PSK"
4576 #define SSL_TXT_3DES "3DES"
4577 #define SSL_TXT_RC4 "RC4"
4578 #define SSL_TXT_AES128 "AES128"
4579 #define SSL_TXT_AES256 "AES256"
4580 #define SSL_TXT_AES "AES"
4581 #define SSL_TXT_AES_GCM "AESGCM"
4582 #define SSL_TXT_CHACHA20 "CHACHA20"
4583 #define SSL_TXT_MD5 "MD5"
4584 #define SSL_TXT_SHA1 "SHA1"
4585 #define SSL_TXT_SHA "SHA"
4586 #define SSL_TXT_SHA256 "SHA256"
4587 #define SSL_TXT_SHA384 "SHA384"
4588 #define SSL_TXT_SSLV3 "SSLv3"
4589 #define SSL_TXT_TLSV1 "TLSv1"
4590 #define SSL_TXT_TLSV1_1 "TLSv1.1"
4591 #define SSL_TXT_TLSV1_2 "TLSv1.2"
4592 #define SSL_TXT_TLSV1_3 "TLSv1.3"
4593 #define SSL_TXT_ALL "ALL"
4594 #define SSL_TXT_CMPDEF "COMPLEMENTOFDEFAULT"
4595 
4596 typedef struct ssl_conf_ctx_st SSL_CONF_CTX;
4597 
4598 // SSL_state returns |SSL_ST_INIT| if a handshake is in progress and |SSL_ST_OK|
4599 // otherwise.
4600 //
4601 // Use |SSL_is_init| instead.
4602 OPENSSL_EXPORT int SSL_state(const SSL *ssl);
4603 
4604 #define SSL_get_state(ssl) SSL_state(ssl)
4605 
4606 // SSL_set_shutdown causes |ssl| to behave as if the shutdown bitmask (see
4607 // |SSL_get_shutdown|) were |mode|. This may be used to skip sending or
4608 // receiving close_notify in |SSL_shutdown| by causing the implementation to
4609 // believe the events already happened.
4610 //
4611 // It is an error to use |SSL_set_shutdown| to unset a bit that has already been
4612 // set. Doing so will trigger an |assert| in debug builds and otherwise be
4613 // ignored.
4614 //
4615 // Use |SSL_CTX_set_quiet_shutdown| instead.
4616 OPENSSL_EXPORT void SSL_set_shutdown(SSL *ssl, int mode);
4617 
4618 // SSL_CTX_set_tmp_ecdh calls |SSL_CTX_set1_curves| with a one-element list
4619 // containing |ec_key|'s curve.
4620 OPENSSL_EXPORT int SSL_CTX_set_tmp_ecdh(SSL_CTX *ctx, const EC_KEY *ec_key);
4621 
4622 // SSL_set_tmp_ecdh calls |SSL_set1_curves| with a one-element list containing
4623 // |ec_key|'s curve.
4624 OPENSSL_EXPORT int SSL_set_tmp_ecdh(SSL *ssl, const EC_KEY *ec_key);
4625 
4626 // SSL_add_dir_cert_subjects_to_stack lists files in directory |dir|. It calls
4627 // |SSL_add_file_cert_subjects_to_stack| on each file and returns one on success
4628 // or zero on error. This function is only available from the libdecrepit
4629 // library.
4630 OPENSSL_EXPORT int SSL_add_dir_cert_subjects_to_stack(STACK_OF(X509_NAME) *out,
4631                                                       const char *dir);
4632 
4633 // SSL_set_verify_result calls |abort| unless |result| is |X509_V_OK|.
4634 //
4635 // TODO(davidben): Remove this function once it has been removed from
4636 // netty-tcnative.
4637 OPENSSL_EXPORT void SSL_set_verify_result(SSL *ssl, long result);
4638 
4639 // SSL_CTX_enable_tls_channel_id calls |SSL_CTX_set_tls_channel_id_enabled|.
4640 OPENSSL_EXPORT int SSL_CTX_enable_tls_channel_id(SSL_CTX *ctx);
4641 
4642 // SSL_enable_tls_channel_id calls |SSL_set_tls_channel_id_enabled|.
4643 OPENSSL_EXPORT int SSL_enable_tls_channel_id(SSL *ssl);
4644 
4645 // BIO_f_ssl returns a |BIO_METHOD| that can wrap an |SSL*| in a |BIO*|. Note
4646 // that this has quite different behaviour from the version in OpenSSL (notably
4647 // that it doesn't try to auto renegotiate).
4648 //
4649 // IMPORTANT: if you are not curl, don't use this.
4650 OPENSSL_EXPORT const BIO_METHOD *BIO_f_ssl(void);
4651 
4652 // BIO_set_ssl sets |ssl| as the underlying connection for |bio|, which must
4653 // have been created using |BIO_f_ssl|. If |take_owership| is true, |bio| will
4654 // call |SSL_free| on |ssl| when closed. It returns one on success or something
4655 // other than one on error.
4656 OPENSSL_EXPORT long BIO_set_ssl(BIO *bio, SSL *ssl, int take_owership);
4657 
4658 // SSL_CTX_set_ecdh_auto returns one.
4659 #define SSL_CTX_set_ecdh_auto(ctx, onoff) 1
4660 
4661 // SSL_set_ecdh_auto returns one.
4662 #define SSL_set_ecdh_auto(ssl, onoff) 1
4663 
4664 // SSL_get_session returns a non-owning pointer to |ssl|'s session. For
4665 // historical reasons, which session it returns depends on |ssl|'s state.
4666 //
4667 // Prior to the start of the initial handshake, it returns the session the
4668 // caller set with |SSL_set_session|. After the initial handshake has finished
4669 // and if no additional handshakes are in progress, it returns the currently
4670 // active session. Its behavior is undefined while a handshake is in progress.
4671 //
4672 // If trying to add new sessions to an external session cache, use
4673 // |SSL_CTX_sess_set_new_cb| instead. In particular, using the callback is
4674 // required as of TLS 1.3. For compatibility, this function will return an
4675 // unresumable session which may be cached, but will never be resumed.
4676 //
4677 // If querying properties of the connection, use APIs on the |SSL| object.
4678 OPENSSL_EXPORT SSL_SESSION *SSL_get_session(const SSL *ssl);
4679 
4680 // SSL_get0_session is an alias for |SSL_get_session|.
4681 #define SSL_get0_session SSL_get_session
4682 
4683 // SSL_get1_session acts like |SSL_get_session| but returns a new reference to
4684 // the session.
4685 OPENSSL_EXPORT SSL_SESSION *SSL_get1_session(SSL *ssl);
4686 
4687 #define OPENSSL_INIT_NO_LOAD_SSL_STRINGS 0
4688 #define OPENSSL_INIT_LOAD_SSL_STRINGS 0
4689 #define OPENSSL_INIT_SSL_DEFAULT 0
4690 
4691 // OPENSSL_init_ssl calls |CRYPTO_library_init| and returns one.
4692 OPENSSL_EXPORT int OPENSSL_init_ssl(uint64_t opts,
4693                                     const OPENSSL_INIT_SETTINGS *settings);
4694 
4695 // The following constants are legacy aliases for RSA-PSS with rsaEncryption
4696 // keys. Use the new names instead.
4697 #define SSL_SIGN_RSA_PSS_SHA256 SSL_SIGN_RSA_PSS_RSAE_SHA256
4698 #define SSL_SIGN_RSA_PSS_SHA384 SSL_SIGN_RSA_PSS_RSAE_SHA384
4699 #define SSL_SIGN_RSA_PSS_SHA512 SSL_SIGN_RSA_PSS_RSAE_SHA512
4700 
4701 // SSL_set_tlsext_status_type configures a client to request OCSP stapling if
4702 // |type| is |TLSEXT_STATUSTYPE_ocsp| and disables it otherwise. It returns one
4703 // on success and zero if handshake configuration has already been shed.
4704 //
4705 // Use |SSL_enable_ocsp_stapling| instead.
4706 OPENSSL_EXPORT int SSL_set_tlsext_status_type(SSL *ssl, int type);
4707 
4708 // SSL_get_tlsext_status_type returns |TLSEXT_STATUSTYPE_ocsp| if the client
4709 // requested OCSP stapling and |TLSEXT_STATUSTYPE_nothing| otherwise. On the
4710 // client, this reflects whether OCSP stapling was enabled via, e.g.,
4711 // |SSL_set_tlsext_status_type|. On the server, this is determined during the
4712 // handshake. It may be queried in callbacks set by |SSL_CTX_set_cert_cb|. The
4713 // result is undefined after the handshake completes.
4714 OPENSSL_EXPORT int SSL_get_tlsext_status_type(const SSL *ssl);
4715 
4716 // SSL_set_tlsext_status_ocsp_resp sets the OCSP response. It returns one on
4717 // success and zero on error. On success, |ssl| takes ownership of |resp|, which
4718 // must have been allocated by |OPENSSL_malloc|.
4719 //
4720 // Use |SSL_set_ocsp_response| instead.
4721 OPENSSL_EXPORT int SSL_set_tlsext_status_ocsp_resp(SSL *ssl, uint8_t *resp,
4722                                                    size_t resp_len);
4723 
4724 // SSL_get_tlsext_status_ocsp_resp sets |*out| to point to the OCSP response
4725 // from the server. It returns the length of the response. If there was no
4726 // response, it sets |*out| to NULL and returns zero.
4727 //
4728 // Use |SSL_get0_ocsp_response| instead.
4729 //
4730 // WARNING: the returned data is not guaranteed to be well formed.
4731 OPENSSL_EXPORT size_t SSL_get_tlsext_status_ocsp_resp(const SSL *ssl,
4732                                                       const uint8_t **out);
4733 
4734 // SSL_CTX_set_tlsext_status_cb configures the legacy OpenSSL OCSP callback and
4735 // returns one. Though the type signature is the same, this callback has
4736 // different behavior for client and server connections:
4737 //
4738 // For clients, the callback is called after certificate verification. It should
4739 // return one for success, zero for a bad OCSP response, and a negative number
4740 // for internal error. Instead, handle this as part of certificate verification.
4741 // (Historically, OpenSSL verified certificates just before parsing stapled OCSP
4742 // responses, but BoringSSL fixes this ordering. All server credentials are
4743 // available during verification.)
4744 //
4745 // Do not use this callback as a server. It is provided for compatibility
4746 // purposes only. For servers, it is called to configure server credentials. It
4747 // should return |SSL_TLSEXT_ERR_OK| on success, |SSL_TLSEXT_ERR_NOACK| to
4748 // ignore OCSP requests, or |SSL_TLSEXT_ERR_ALERT_FATAL| on error. It is usually
4749 // used to fetch OCSP responses on demand, which is not ideal. Instead, treat
4750 // OCSP responses like other server credentials, such as certificates or SCT
4751 // lists. Configure, store, and refresh them eagerly. This avoids downtime if
4752 // the CA's OCSP responder is briefly offline.
4753 OPENSSL_EXPORT int SSL_CTX_set_tlsext_status_cb(SSL_CTX *ctx,
4754                                                 int (*callback)(SSL *ssl,
4755                                                                 void *arg));
4756 
4757 // SSL_CTX_set_tlsext_status_arg sets additional data for
4758 // |SSL_CTX_set_tlsext_status_cb|'s callback and returns one.
4759 OPENSSL_EXPORT int SSL_CTX_set_tlsext_status_arg(SSL_CTX *ctx, void *arg);
4760 
4761 // The following symbols are compatibility aliases for reason codes used when
4762 // receiving an alert from the peer. Use the other names instead, which fit the
4763 // naming convention.
4764 //
4765 // TODO(davidben): Fix references to |SSL_R_TLSV1_CERTIFICATE_REQUIRED| and
4766 // remove the compatibility value. The others come from OpenSSL.
4767 #define SSL_R_TLSV1_UNSUPPORTED_EXTENSION \
4768   SSL_R_TLSV1_ALERT_UNSUPPORTED_EXTENSION
4769 #define SSL_R_TLSV1_CERTIFICATE_UNOBTAINABLE \
4770   SSL_R_TLSV1_ALERT_CERTIFICATE_UNOBTAINABLE
4771 #define SSL_R_TLSV1_UNRECOGNIZED_NAME SSL_R_TLSV1_ALERT_UNRECOGNIZED_NAME
4772 #define SSL_R_TLSV1_BAD_CERTIFICATE_STATUS_RESPONSE \
4773   SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE
4774 #define SSL_R_TLSV1_BAD_CERTIFICATE_HASH_VALUE \
4775   SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_HASH_VALUE
4776 #define SSL_R_TLSV1_CERTIFICATE_REQUIRED SSL_R_TLSV1_ALERT_CERTIFICATE_REQUIRED
4777 
4778 // SSL_CIPHER_get_value calls |SSL_CIPHER_get_protocol_id|.
4779 //
4780 // TODO(davidben): |SSL_CIPHER_get_value| was our name for this function, but
4781 // upstream added it as |SSL_CIPHER_get_protocol_id|. Switch callers to the new
4782 // name and remove this one.
4783 OPENSSL_EXPORT uint16_t SSL_CIPHER_get_value(const SSL_CIPHER *cipher);
4784 
4785 // SSL_CTX_set_ignore_tls13_downgrade does nothing.
4786 OPENSSL_EXPORT void SSL_CTX_set_ignore_tls13_downgrade(SSL_CTX *ctx,
4787                                                        int ignore);
4788 
4789 // SSL_set_ignore_tls13_downgrade does nothing.
4790 OPENSSL_EXPORT void SSL_set_ignore_tls13_downgrade(SSL *ssl, int ignore);
4791 
4792 // SSL_is_tls13_downgrade returns zero. Historically, this function returned
4793 // whether the TLS 1.3 downgrade signal would have been enforced if not
4794 // disabled. The TLS 1.3 downgrade signal is now always enforced.
4795 OPENSSL_EXPORT int SSL_is_tls13_downgrade(const SSL *ssl);
4796 
4797 
4798 // Nodejs compatibility section (hidden).
4799 //
4800 // These defines exist for node.js, with the hope that we can eliminate the
4801 // need for them over time.
4802 
4803 #define SSLerr(function, reason) \
4804   ERR_put_error(ERR_LIB_SSL, 0, reason, __FILE__, __LINE__)
4805 
4806 
4807 // Preprocessor compatibility section (hidden).
4808 //
4809 // Historically, a number of APIs were implemented in OpenSSL as macros and
4810 // constants to 'ctrl' functions. To avoid breaking #ifdefs in consumers, this
4811 // section defines a number of legacy macros.
4812 //
4813 // Although using either the CTRL values or their wrapper macros in #ifdefs is
4814 // still supported, the CTRL values may not be passed to |SSL_ctrl| and
4815 // |SSL_CTX_ctrl|. Call the functions (previously wrapper macros) instead.
4816 //
4817 // See PORTING.md in the BoringSSL source tree for a table of corresponding
4818 // functions.
4819 // https://boringssl.googlesource.com/boringssl/+/master/PORTING.md#Replacements-for-values
4820 
4821 #define DTLS_CTRL_GET_TIMEOUT doesnt_exist
4822 #define DTLS_CTRL_HANDLE_TIMEOUT doesnt_exist
4823 #define SSL_CTRL_CHAIN doesnt_exist
4824 #define SSL_CTRL_CHAIN_CERT doesnt_exist
4825 #define SSL_CTRL_CHANNEL_ID doesnt_exist
4826 #define SSL_CTRL_CLEAR_EXTRA_CHAIN_CERTS doesnt_exist
4827 #define SSL_CTRL_CLEAR_MODE doesnt_exist
4828 #define SSL_CTRL_CLEAR_OPTIONS doesnt_exist
4829 #define SSL_CTRL_EXTRA_CHAIN_CERT doesnt_exist
4830 #define SSL_CTRL_GET_CHAIN_CERTS doesnt_exist
4831 #define SSL_CTRL_GET_CHANNEL_ID doesnt_exist
4832 #define SSL_CTRL_GET_CLIENT_CERT_TYPES doesnt_exist
4833 #define SSL_CTRL_GET_EXTRA_CHAIN_CERTS doesnt_exist
4834 #define SSL_CTRL_GET_MAX_CERT_LIST doesnt_exist
4835 #define SSL_CTRL_GET_NUM_RENEGOTIATIONS doesnt_exist
4836 #define SSL_CTRL_GET_READ_AHEAD doesnt_exist
4837 #define SSL_CTRL_GET_RI_SUPPORT doesnt_exist
4838 #define SSL_CTRL_GET_SERVER_TMP_KEY doesnt_exist
4839 #define SSL_CTRL_GET_SESSION_REUSED doesnt_exist
4840 #define SSL_CTRL_GET_SESS_CACHE_MODE doesnt_exist
4841 #define SSL_CTRL_GET_SESS_CACHE_SIZE doesnt_exist
4842 #define SSL_CTRL_GET_TLSEXT_TICKET_KEYS doesnt_exist
4843 #define SSL_CTRL_GET_TOTAL_RENEGOTIATIONS doesnt_exist
4844 #define SSL_CTRL_MODE doesnt_exist
4845 #define SSL_CTRL_NEED_TMP_RSA doesnt_exist
4846 #define SSL_CTRL_OPTIONS doesnt_exist
4847 #define SSL_CTRL_SESS_NUMBER doesnt_exist
4848 #define SSL_CTRL_SET_CURVES doesnt_exist
4849 #define SSL_CTRL_SET_CURVES_LIST doesnt_exist
4850 #define SSL_CTRL_SET_ECDH_AUTO doesnt_exist
4851 #define SSL_CTRL_SET_MAX_CERT_LIST doesnt_exist
4852 #define SSL_CTRL_SET_MAX_SEND_FRAGMENT doesnt_exist
4853 #define SSL_CTRL_SET_MSG_CALLBACK doesnt_exist
4854 #define SSL_CTRL_SET_MSG_CALLBACK_ARG doesnt_exist
4855 #define SSL_CTRL_SET_MTU doesnt_exist
4856 #define SSL_CTRL_SET_READ_AHEAD doesnt_exist
4857 #define SSL_CTRL_SET_SESS_CACHE_MODE doesnt_exist
4858 #define SSL_CTRL_SET_SESS_CACHE_SIZE doesnt_exist
4859 #define SSL_CTRL_SET_TLSEXT_HOSTNAME doesnt_exist
4860 #define SSL_CTRL_SET_TLSEXT_SERVERNAME_ARG doesnt_exist
4861 #define SSL_CTRL_SET_TLSEXT_SERVERNAME_CB doesnt_exist
4862 #define SSL_CTRL_SET_TLSEXT_TICKET_KEYS doesnt_exist
4863 #define SSL_CTRL_SET_TLSEXT_TICKET_KEY_CB doesnt_exist
4864 #define SSL_CTRL_SET_TMP_DH doesnt_exist
4865 #define SSL_CTRL_SET_TMP_DH_CB doesnt_exist
4866 #define SSL_CTRL_SET_TMP_ECDH doesnt_exist
4867 #define SSL_CTRL_SET_TMP_ECDH_CB doesnt_exist
4868 #define SSL_CTRL_SET_TMP_RSA doesnt_exist
4869 #define SSL_CTRL_SET_TMP_RSA_CB doesnt_exist
4870 
4871 // |BORINGSSL_PREFIX| already makes each of these symbols into macros, so there
4872 // is no need to define conflicting macros.
4873 #if !defined(BORINGSSL_PREFIX)
4874 
4875 #define DTLSv1_get_timeout DTLSv1_get_timeout
4876 #define DTLSv1_handle_timeout DTLSv1_handle_timeout
4877 #define SSL_CTX_add0_chain_cert SSL_CTX_add0_chain_cert
4878 #define SSL_CTX_add1_chain_cert SSL_CTX_add1_chain_cert
4879 #define SSL_CTX_add_extra_chain_cert SSL_CTX_add_extra_chain_cert
4880 #define SSL_CTX_clear_extra_chain_certs SSL_CTX_clear_extra_chain_certs
4881 #define SSL_CTX_clear_chain_certs SSL_CTX_clear_chain_certs
4882 #define SSL_CTX_clear_mode SSL_CTX_clear_mode
4883 #define SSL_CTX_clear_options SSL_CTX_clear_options
4884 #define SSL_CTX_get0_chain_certs SSL_CTX_get0_chain_certs
4885 #define SSL_CTX_get_extra_chain_certs SSL_CTX_get_extra_chain_certs
4886 #define SSL_CTX_get_max_cert_list SSL_CTX_get_max_cert_list
4887 #define SSL_CTX_get_mode SSL_CTX_get_mode
4888 #define SSL_CTX_get_options SSL_CTX_get_options
4889 #define SSL_CTX_get_read_ahead SSL_CTX_get_read_ahead
4890 #define SSL_CTX_get_session_cache_mode SSL_CTX_get_session_cache_mode
4891 #define SSL_CTX_get_tlsext_ticket_keys SSL_CTX_get_tlsext_ticket_keys
4892 #define SSL_CTX_need_tmp_RSA SSL_CTX_need_tmp_RSA
4893 #define SSL_CTX_sess_get_cache_size SSL_CTX_sess_get_cache_size
4894 #define SSL_CTX_sess_number SSL_CTX_sess_number
4895 #define SSL_CTX_sess_set_cache_size SSL_CTX_sess_set_cache_size
4896 #define SSL_CTX_set0_chain SSL_CTX_set0_chain
4897 #define SSL_CTX_set1_chain SSL_CTX_set1_chain
4898 #define SSL_CTX_set1_curves SSL_CTX_set1_curves
4899 #define SSL_CTX_set_max_cert_list SSL_CTX_set_max_cert_list
4900 #define SSL_CTX_set_max_send_fragment SSL_CTX_set_max_send_fragment
4901 #define SSL_CTX_set_mode SSL_CTX_set_mode
4902 #define SSL_CTX_set_msg_callback_arg SSL_CTX_set_msg_callback_arg
4903 #define SSL_CTX_set_options SSL_CTX_set_options
4904 #define SSL_CTX_set_read_ahead SSL_CTX_set_read_ahead
4905 #define SSL_CTX_set_session_cache_mode SSL_CTX_set_session_cache_mode
4906 #define SSL_CTX_set_tlsext_servername_arg SSL_CTX_set_tlsext_servername_arg
4907 #define SSL_CTX_set_tlsext_servername_callback \
4908     SSL_CTX_set_tlsext_servername_callback
4909 #define SSL_CTX_set_tlsext_ticket_key_cb SSL_CTX_set_tlsext_ticket_key_cb
4910 #define SSL_CTX_set_tlsext_ticket_keys SSL_CTX_set_tlsext_ticket_keys
4911 #define SSL_CTX_set_tmp_dh SSL_CTX_set_tmp_dh
4912 #define SSL_CTX_set_tmp_ecdh SSL_CTX_set_tmp_ecdh
4913 #define SSL_CTX_set_tmp_rsa SSL_CTX_set_tmp_rsa
4914 #define SSL_add0_chain_cert SSL_add0_chain_cert
4915 #define SSL_add1_chain_cert SSL_add1_chain_cert
4916 #define SSL_clear_chain_certs SSL_clear_chain_certs
4917 #define SSL_clear_mode SSL_clear_mode
4918 #define SSL_clear_options SSL_clear_options
4919 #define SSL_get0_certificate_types SSL_get0_certificate_types
4920 #define SSL_get0_chain_certs SSL_get0_chain_certs
4921 #define SSL_get_max_cert_list SSL_get_max_cert_list
4922 #define SSL_get_mode SSL_get_mode
4923 #define SSL_get_options SSL_get_options
4924 #define SSL_get_secure_renegotiation_support \
4925     SSL_get_secure_renegotiation_support
4926 #define SSL_need_tmp_RSA SSL_need_tmp_RSA
4927 #define SSL_num_renegotiations SSL_num_renegotiations
4928 #define SSL_session_reused SSL_session_reused
4929 #define SSL_set0_chain SSL_set0_chain
4930 #define SSL_set1_chain SSL_set1_chain
4931 #define SSL_set1_curves SSL_set1_curves
4932 #define SSL_set_max_cert_list SSL_set_max_cert_list
4933 #define SSL_set_max_send_fragment SSL_set_max_send_fragment
4934 #define SSL_set_mode SSL_set_mode
4935 #define SSL_set_msg_callback_arg SSL_set_msg_callback_arg
4936 #define SSL_set_mtu SSL_set_mtu
4937 #define SSL_set_options SSL_set_options
4938 #define SSL_set_tlsext_host_name SSL_set_tlsext_host_name
4939 #define SSL_set_tmp_dh SSL_set_tmp_dh
4940 #define SSL_set_tmp_ecdh SSL_set_tmp_ecdh
4941 #define SSL_set_tmp_rsa SSL_set_tmp_rsa
4942 #define SSL_total_renegotiations SSL_total_renegotiations
4943 
4944 #endif // !defined(BORINGSSL_PREFIX)
4945 
4946 
4947 #if defined(__cplusplus)
4948 }  // extern C
4949 
4950 #if !defined(BORINGSSL_NO_CXX)
4951 
4952 extern "C++" {
4953 
4954 BSSL_NAMESPACE_BEGIN
4955 
4956 BORINGSSL_MAKE_DELETER(SSL, SSL_free)
4957 BORINGSSL_MAKE_DELETER(SSL_CTX, SSL_CTX_free)
4958 BORINGSSL_MAKE_UP_REF(SSL_CTX, SSL_CTX_up_ref)
4959 BORINGSSL_MAKE_DELETER(SSL_SESSION, SSL_SESSION_free)
4960 BORINGSSL_MAKE_UP_REF(SSL_SESSION, SSL_SESSION_up_ref)
4961 
4962 enum class OpenRecordResult {
4963   kOK,
4964   kDiscard,
4965   kIncompleteRecord,
4966   kAlertCloseNotify,
4967   kError,
4968 };
4969 
4970 //  *** EXPERIMENTAL -- DO NOT USE ***
4971 //
4972 // OpenRecord decrypts the first complete SSL record from |in| in-place, sets
4973 // |out| to the decrypted application data, and |out_record_len| to the length
4974 // of the encrypted record. Returns:
4975 // - kOK if an application-data record was successfully decrypted and verified.
4976 // - kDiscard if a record was sucessfully processed, but should be discarded.
4977 // - kIncompleteRecord if |in| did not contain a complete record.
4978 // - kAlertCloseNotify if a record was successfully processed but is a
4979 //   close_notify alert.
4980 // - kError if an error occurred or the record is invalid. |*out_alert| will be
4981 //   set to an alert to emit, or zero if no alert should be emitted.
4982 OPENSSL_EXPORT OpenRecordResult OpenRecord(SSL *ssl, Span<uint8_t> *out,
4983                                            size_t *out_record_len,
4984                                            uint8_t *out_alert,
4985                                            Span<uint8_t> in);
4986 
4987 OPENSSL_EXPORT size_t SealRecordPrefixLen(const SSL *ssl, size_t plaintext_len);
4988 
4989 // SealRecordSuffixLen returns the length of the suffix written by |SealRecord|.
4990 //
4991 // |plaintext_len| must be equal to the size of the plaintext passed to
4992 // |SealRecord|.
4993 //
4994 // |plaintext_len| must not exceed |SSL3_RT_MAX_PLAINTEXT_LENGTH|. The returned
4995 // suffix length will not exceed |SSL3_RT_MAX_ENCRYPTED_OVERHEAD|.
4996 OPENSSL_EXPORT size_t SealRecordSuffixLen(const SSL *ssl, size_t plaintext_len);
4997 
4998 //  *** EXPERIMENTAL -- DO NOT USE ***
4999 //
5000 // SealRecord encrypts the cleartext of |in| and scatters the resulting TLS
5001 // application data record between |out_prefix|, |out|, and |out_suffix|. It
5002 // returns true on success or false if an error occurred.
5003 //
5004 // The length of |out_prefix| must equal |SealRecordPrefixLen|. The length of
5005 // |out| must equal the length of |in|, which must not exceed
5006 // |SSL3_RT_MAX_PLAINTEXT_LENGTH|. The length of |out_suffix| must equal
5007 // |SealRecordSuffixLen|.
5008 //
5009 // If enabled, |SealRecord| may perform TLS 1.0 CBC 1/n-1 record splitting.
5010 // |SealRecordPrefixLen| accounts for the required overhead if that is the case.
5011 //
5012 // |out| may equal |in| to encrypt in-place but may not otherwise alias.
5013 // |out_prefix| and |out_suffix| may not alias anything.
5014 OPENSSL_EXPORT bool SealRecord(SSL *ssl, Span<uint8_t> out_prefix,
5015                                Span<uint8_t> out, Span<uint8_t> out_suffix,
5016                                Span<const uint8_t> in);
5017 
5018 
5019 // *** EXPERIMENTAL — DO NOT USE WITHOUT CHECKING ***
5020 //
5021 // Split handshakes.
5022 //
5023 // Split handshakes allows the handshake part of a TLS connection to be
5024 // performed in a different process (or on a different machine) than the data
5025 // exchange. This only applies to servers.
5026 //
5027 // In the first part of a split handshake, an |SSL| (where the |SSL_CTX| has
5028 // been configured with |SSL_CTX_set_handoff_mode|) is used normally. Once the
5029 // ClientHello message has been received, the handshake will stop and
5030 // |SSL_get_error| will indicate |SSL_ERROR_HANDOFF|. At this point (and only
5031 // at this point), |SSL_serialize_handoff| can be called to write the “handoff”
5032 // state of the connection.
5033 //
5034 // Elsewhere, a fresh |SSL| can be used with |SSL_apply_handoff| to continue
5035 // the connection. The connection from the client is fed into this |SSL|, and
5036 // the handshake resumed. When the handshake stops again and |SSL_get_error|
5037 // indicates |SSL_ERROR_HANDBACK|, |SSL_serialize_handback| should be called to
5038 // serialize the state of the handshake again.
5039 //
5040 // Back at the first location, a fresh |SSL| can be used with
5041 // |SSL_apply_handback|. Then the client's connection can be processed mostly
5042 // as normal.
5043 //
5044 // Lastly, when a connection is in the handoff state, whether or not
5045 // |SSL_serialize_handoff| is called, |SSL_decline_handoff| will move it back
5046 // into a normal state where the connection can proceed without impact.
5047 //
5048 // WARNING: Currently only works with TLS 1.0–1.2.
5049 // WARNING: The serialisation formats are not yet stable: version skew may be
5050 //     fatal.
5051 // WARNING: The handback data contains sensitive key material and must be
5052 //     protected.
5053 // WARNING: Some calls on the final |SSL| will not work. Just as an example,
5054 //     calls like |SSL_get0_session_id_context| and |SSL_get_privatekey| won't
5055 //     work because the certificate used for handshaking isn't available.
5056 // WARNING: |SSL_apply_handoff| may trigger “msg” callback calls.
5057 
5058 OPENSSL_EXPORT void SSL_CTX_set_handoff_mode(SSL_CTX *ctx, bool on);
5059 OPENSSL_EXPORT void SSL_set_handoff_mode(SSL *SSL, bool on);
5060 OPENSSL_EXPORT bool SSL_serialize_handoff(const SSL *ssl, CBB *out,
5061                                           SSL_CLIENT_HELLO *out_hello);
5062 OPENSSL_EXPORT bool SSL_decline_handoff(SSL *ssl);
5063 OPENSSL_EXPORT bool SSL_apply_handoff(SSL *ssl, Span<const uint8_t> handoff);
5064 OPENSSL_EXPORT bool SSL_serialize_handback(const SSL *ssl, CBB *out);
5065 OPENSSL_EXPORT bool SSL_apply_handback(SSL *ssl, Span<const uint8_t> handback);
5066 
5067 // SSL_get_traffic_secrets sets |*out_read_traffic_secret| and
5068 // |*out_write_traffic_secret| to reference the TLS 1.3 traffic secrets for
5069 // |ssl|. This function is only valid on TLS 1.3 connections that have
5070 // completed the handshake. It returns true on success and false on error.
5071 OPENSSL_EXPORT bool SSL_get_traffic_secrets(
5072     const SSL *ssl, Span<const uint8_t> *out_read_traffic_secret,
5073     Span<const uint8_t> *out_write_traffic_secret);
5074 
5075 BSSL_NAMESPACE_END
5076 
5077 }  // extern C++
5078 
5079 #endif  // !defined(BORINGSSL_NO_CXX)
5080 
5081 #endif
5082 
5083 #define SSL_R_APP_DATA_IN_HANDSHAKE 100
5084 #define SSL_R_ATTEMPT_TO_REUSE_SESSION_IN_DIFFERENT_CONTEXT 101
5085 #define SSL_R_BAD_ALERT 102
5086 #define SSL_R_BAD_CHANGE_CIPHER_SPEC 103
5087 #define SSL_R_BAD_DATA_RETURNED_BY_CALLBACK 104
5088 #define SSL_R_BAD_DH_P_LENGTH 105
5089 #define SSL_R_BAD_DIGEST_LENGTH 106
5090 #define SSL_R_BAD_ECC_CERT 107
5091 #define SSL_R_BAD_ECPOINT 108
5092 #define SSL_R_BAD_HANDSHAKE_RECORD 109
5093 #define SSL_R_BAD_HELLO_REQUEST 110
5094 #define SSL_R_BAD_LENGTH 111
5095 #define SSL_R_BAD_PACKET_LENGTH 112
5096 #define SSL_R_BAD_RSA_ENCRYPT 113
5097 #define SSL_R_BAD_SIGNATURE 114
5098 #define SSL_R_BAD_SRTP_MKI_VALUE 115
5099 #define SSL_R_BAD_SRTP_PROTECTION_PROFILE_LIST 116
5100 #define SSL_R_BAD_SSL_FILETYPE 117
5101 #define SSL_R_BAD_WRITE_RETRY 118
5102 #define SSL_R_BIO_NOT_SET 119
5103 #define SSL_R_BN_LIB 120
5104 #define SSL_R_BUFFER_TOO_SMALL 121
5105 #define SSL_R_CA_DN_LENGTH_MISMATCH 122
5106 #define SSL_R_CA_DN_TOO_LONG 123
5107 #define SSL_R_CCS_RECEIVED_EARLY 124
5108 #define SSL_R_CERTIFICATE_VERIFY_FAILED 125
5109 #define SSL_R_CERT_CB_ERROR 126
5110 #define SSL_R_CERT_LENGTH_MISMATCH 127
5111 #define SSL_R_CHANNEL_ID_NOT_P256 128
5112 #define SSL_R_CHANNEL_ID_SIGNATURE_INVALID 129
5113 #define SSL_R_CIPHER_OR_HASH_UNAVAILABLE 130
5114 #define SSL_R_CLIENTHELLO_PARSE_FAILED 131
5115 #define SSL_R_CLIENTHELLO_TLSEXT 132
5116 #define SSL_R_CONNECTION_REJECTED 133
5117 #define SSL_R_CONNECTION_TYPE_NOT_SET 134
5118 #define SSL_R_CUSTOM_EXTENSION_ERROR 135
5119 #define SSL_R_DATA_LENGTH_TOO_LONG 136
5120 #define SSL_R_DECODE_ERROR 137
5121 #define SSL_R_DECRYPTION_FAILED 138
5122 #define SSL_R_DECRYPTION_FAILED_OR_BAD_RECORD_MAC 139
5123 #define SSL_R_DH_PUBLIC_VALUE_LENGTH_IS_WRONG 140
5124 #define SSL_R_DH_P_TOO_LONG 141
5125 #define SSL_R_DIGEST_CHECK_FAILED 142
5126 #define SSL_R_DTLS_MESSAGE_TOO_BIG 143
5127 #define SSL_R_ECC_CERT_NOT_FOR_SIGNING 144
5128 #define SSL_R_EMS_STATE_INCONSISTENT 145
5129 #define SSL_R_ENCRYPTED_LENGTH_TOO_LONG 146
5130 #define SSL_R_ERROR_ADDING_EXTENSION 147
5131 #define SSL_R_ERROR_IN_RECEIVED_CIPHER_LIST 148
5132 #define SSL_R_ERROR_PARSING_EXTENSION 149
5133 #define SSL_R_EXCESSIVE_MESSAGE_SIZE 150
5134 #define SSL_R_EXTRA_DATA_IN_MESSAGE 151
5135 #define SSL_R_FRAGMENT_MISMATCH 152
5136 #define SSL_R_GOT_NEXT_PROTO_WITHOUT_EXTENSION 153
5137 #define SSL_R_HANDSHAKE_FAILURE_ON_CLIENT_HELLO 154
5138 #define SSL_R_HTTPS_PROXY_REQUEST 155
5139 #define SSL_R_HTTP_REQUEST 156
5140 #define SSL_R_INAPPROPRIATE_FALLBACK 157
5141 #define SSL_R_INVALID_COMMAND 158
5142 #define SSL_R_INVALID_MESSAGE 159
5143 #define SSL_R_INVALID_SSL_SESSION 160
5144 #define SSL_R_INVALID_TICKET_KEYS_LENGTH 161
5145 #define SSL_R_LENGTH_MISMATCH 162
5146 #define SSL_R_MISSING_EXTENSION 164
5147 #define SSL_R_MISSING_RSA_CERTIFICATE 165
5148 #define SSL_R_MISSING_TMP_DH_KEY 166
5149 #define SSL_R_MISSING_TMP_ECDH_KEY 167
5150 #define SSL_R_MIXED_SPECIAL_OPERATOR_WITH_GROUPS 168
5151 #define SSL_R_MTU_TOO_SMALL 169
5152 #define SSL_R_NEGOTIATED_BOTH_NPN_AND_ALPN 170
5153 #define SSL_R_NESTED_GROUP 171
5154 #define SSL_R_NO_CERTIFICATES_RETURNED 172
5155 #define SSL_R_NO_CERTIFICATE_ASSIGNED 173
5156 #define SSL_R_NO_CERTIFICATE_SET 174
5157 #define SSL_R_NO_CIPHERS_AVAILABLE 175
5158 #define SSL_R_NO_CIPHERS_PASSED 176
5159 #define SSL_R_NO_CIPHER_MATCH 177
5160 #define SSL_R_NO_COMPRESSION_SPECIFIED 178
5161 #define SSL_R_NO_METHOD_SPECIFIED 179
5162 #define SSL_R_NO_P256_SUPPORT 180
5163 #define SSL_R_NO_PRIVATE_KEY_ASSIGNED 181
5164 #define SSL_R_NO_RENEGOTIATION 182
5165 #define SSL_R_NO_REQUIRED_DIGEST 183
5166 #define SSL_R_NO_SHARED_CIPHER 184
5167 #define SSL_R_NULL_SSL_CTX 185
5168 #define SSL_R_NULL_SSL_METHOD_PASSED 186
5169 #define SSL_R_OLD_SESSION_CIPHER_NOT_RETURNED 187
5170 #define SSL_R_OLD_SESSION_VERSION_NOT_RETURNED 188
5171 #define SSL_R_OUTPUT_ALIASES_INPUT 189
5172 #define SSL_R_PARSE_TLSEXT 190
5173 #define SSL_R_PATH_TOO_LONG 191
5174 #define SSL_R_PEER_DID_NOT_RETURN_A_CERTIFICATE 192
5175 #define SSL_R_PEER_ERROR_UNSUPPORTED_CERTIFICATE_TYPE 193
5176 #define SSL_R_PROTOCOL_IS_SHUTDOWN 194
5177 #define SSL_R_PSK_IDENTITY_NOT_FOUND 195
5178 #define SSL_R_PSK_NO_CLIENT_CB 196
5179 #define SSL_R_PSK_NO_SERVER_CB 197
5180 #define SSL_R_READ_TIMEOUT_EXPIRED 198
5181 #define SSL_R_RECORD_LENGTH_MISMATCH 199
5182 #define SSL_R_RECORD_TOO_LARGE 200
5183 #define SSL_R_RENEGOTIATION_ENCODING_ERR 201
5184 #define SSL_R_RENEGOTIATION_MISMATCH 202
5185 #define SSL_R_REQUIRED_CIPHER_MISSING 203
5186 #define SSL_R_RESUMED_EMS_SESSION_WITHOUT_EMS_EXTENSION 204
5187 #define SSL_R_RESUMED_NON_EMS_SESSION_WITH_EMS_EXTENSION 205
5188 #define SSL_R_SCSV_RECEIVED_WHEN_RENEGOTIATING 206
5189 #define SSL_R_SERVERHELLO_TLSEXT 207
5190 #define SSL_R_SESSION_ID_CONTEXT_UNINITIALIZED 208
5191 #define SSL_R_SESSION_MAY_NOT_BE_CREATED 209
5192 #define SSL_R_SIGNATURE_ALGORITHMS_EXTENSION_SENT_BY_SERVER 210
5193 #define SSL_R_SRTP_COULD_NOT_ALLOCATE_PROFILES 211
5194 #define SSL_R_SRTP_UNKNOWN_PROTECTION_PROFILE 212
5195 #define SSL_R_SSL3_EXT_INVALID_SERVERNAME 213
5196 #define SSL_R_SSL_CTX_HAS_NO_DEFAULT_SSL_VERSION 214
5197 #define SSL_R_SSL_HANDSHAKE_FAILURE 215
5198 #define SSL_R_SSL_SESSION_ID_CONTEXT_TOO_LONG 216
5199 #define SSL_R_TLS_PEER_DID_NOT_RESPOND_WITH_CERTIFICATE_LIST 217
5200 #define SSL_R_TLS_RSA_ENCRYPTED_VALUE_LENGTH_IS_WRONG 218
5201 #define SSL_R_TOO_MANY_EMPTY_FRAGMENTS 219
5202 #define SSL_R_TOO_MANY_WARNING_ALERTS 220
5203 #define SSL_R_UNABLE_TO_FIND_ECDH_PARAMETERS 221
5204 #define SSL_R_UNEXPECTED_EXTENSION 222
5205 #define SSL_R_UNEXPECTED_MESSAGE 223
5206 #define SSL_R_UNEXPECTED_OPERATOR_IN_GROUP 224
5207 #define SSL_R_UNEXPECTED_RECORD 225
5208 #define SSL_R_UNINITIALIZED 226
5209 #define SSL_R_UNKNOWN_ALERT_TYPE 227
5210 #define SSL_R_UNKNOWN_CERTIFICATE_TYPE 228
5211 #define SSL_R_UNKNOWN_CIPHER_RETURNED 229
5212 #define SSL_R_UNKNOWN_CIPHER_TYPE 230
5213 #define SSL_R_UNKNOWN_DIGEST 231
5214 #define SSL_R_UNKNOWN_KEY_EXCHANGE_TYPE 232
5215 #define SSL_R_UNKNOWN_PROTOCOL 233
5216 #define SSL_R_UNKNOWN_SSL_VERSION 234
5217 #define SSL_R_UNKNOWN_STATE 235
5218 #define SSL_R_UNSAFE_LEGACY_RENEGOTIATION_DISABLED 236
5219 #define SSL_R_UNSUPPORTED_CIPHER 237
5220 #define SSL_R_UNSUPPORTED_COMPRESSION_ALGORITHM 238
5221 #define SSL_R_UNSUPPORTED_ELLIPTIC_CURVE 239
5222 #define SSL_R_UNSUPPORTED_PROTOCOL 240
5223 #define SSL_R_WRONG_CERTIFICATE_TYPE 241
5224 #define SSL_R_WRONG_CIPHER_RETURNED 242
5225 #define SSL_R_WRONG_CURVE 243
5226 #define SSL_R_WRONG_MESSAGE_TYPE 244
5227 #define SSL_R_WRONG_SIGNATURE_TYPE 245
5228 #define SSL_R_WRONG_SSL_VERSION 246
5229 #define SSL_R_WRONG_VERSION_NUMBER 247
5230 #define SSL_R_X509_LIB 248
5231 #define SSL_R_X509_VERIFICATION_SETUP_PROBLEMS 249
5232 #define SSL_R_SHUTDOWN_WHILE_IN_INIT 250
5233 #define SSL_R_INVALID_OUTER_RECORD_TYPE 251
5234 #define SSL_R_UNSUPPORTED_PROTOCOL_FOR_CUSTOM_KEY 252
5235 #define SSL_R_NO_COMMON_SIGNATURE_ALGORITHMS 253
5236 #define SSL_R_DOWNGRADE_DETECTED 254
5237 #define SSL_R_EXCESS_HANDSHAKE_DATA 255
5238 #define SSL_R_INVALID_COMPRESSION_LIST 256
5239 #define SSL_R_DUPLICATE_EXTENSION 257
5240 #define SSL_R_MISSING_KEY_SHARE 258
5241 #define SSL_R_INVALID_ALPN_PROTOCOL 259
5242 #define SSL_R_TOO_MANY_KEY_UPDATES 260
5243 #define SSL_R_BLOCK_CIPHER_PAD_IS_WRONG 261
5244 #define SSL_R_NO_CIPHERS_SPECIFIED 262
5245 #define SSL_R_RENEGOTIATION_EMS_MISMATCH 263
5246 #define SSL_R_DUPLICATE_KEY_SHARE 264
5247 #define SSL_R_NO_GROUPS_SPECIFIED 265
5248 #define SSL_R_NO_SHARED_GROUP 266
5249 #define SSL_R_PRE_SHARED_KEY_MUST_BE_LAST 267
5250 #define SSL_R_OLD_SESSION_PRF_HASH_MISMATCH 268
5251 #define SSL_R_INVALID_SCT_LIST 269
5252 #define SSL_R_TOO_MUCH_SKIPPED_EARLY_DATA 270
5253 #define SSL_R_PSK_IDENTITY_BINDER_COUNT_MISMATCH 271
5254 #define SSL_R_CANNOT_PARSE_LEAF_CERT 272
5255 #define SSL_R_SERVER_CERT_CHANGED 273
5256 #define SSL_R_CERTIFICATE_AND_PRIVATE_KEY_MISMATCH 274
5257 #define SSL_R_CANNOT_HAVE_BOTH_PRIVKEY_AND_METHOD 275
5258 #define SSL_R_TICKET_ENCRYPTION_FAILED 276
5259 #define SSL_R_ALPN_MISMATCH_ON_EARLY_DATA 277
5260 #define SSL_R_WRONG_VERSION_ON_EARLY_DATA 278
5261 #define SSL_R_UNEXPECTED_EXTENSION_ON_EARLY_DATA 279
5262 #define SSL_R_NO_SUPPORTED_VERSIONS_ENABLED 280
5263 #define SSL_R_APPLICATION_DATA_INSTEAD_OF_HANDSHAKE 281
5264 #define SSL_R_EMPTY_HELLO_RETRY_REQUEST 282
5265 #define SSL_R_EARLY_DATA_NOT_IN_USE 283
5266 #define SSL_R_HANDSHAKE_NOT_COMPLETE 284
5267 #define SSL_R_NEGOTIATED_TB_WITHOUT_EMS_OR_RI 285
5268 #define SSL_R_SERVER_ECHOED_INVALID_SESSION_ID 286
5269 #define SSL_R_PRIVATE_KEY_OPERATION_FAILED 287
5270 #define SSL_R_SECOND_SERVERHELLO_VERSION_MISMATCH 288
5271 #define SSL_R_OCSP_CB_ERROR 289
5272 #define SSL_R_SSL_SESSION_ID_TOO_LONG 290
5273 #define SSL_R_APPLICATION_DATA_ON_SHUTDOWN 291
5274 #define SSL_R_CERT_DECOMPRESSION_FAILED 292
5275 #define SSL_R_UNCOMPRESSED_CERT_TOO_LARGE 293
5276 #define SSL_R_UNKNOWN_CERT_COMPRESSION_ALG 294
5277 #define SSL_R_INVALID_SIGNATURE_ALGORITHM 295
5278 #define SSL_R_DUPLICATE_SIGNATURE_ALGORITHM 296
5279 #define SSL_R_TLS13_DOWNGRADE 297
5280 #define SSL_R_QUIC_INTERNAL_ERROR 298
5281 #define SSL_R_WRONG_ENCRYPTION_LEVEL_RECEIVED 299
5282 #define SSL_R_TOO_MUCH_READ_EARLY_DATA 300
5283 #define SSL_R_INVALID_DELEGATED_CREDENTIAL 301
5284 #define SSL_R_KEY_USAGE_BIT_INCORRECT 302
5285 #define SSL_R_INCONSISTENT_CLIENT_HELLO 303
5286 #define SSL_R_CIPHER_MISMATCH_ON_EARLY_DATA 304
5287 #define SSL_R_QUIC_TRANSPORT_PARAMETERS_MISCONFIGURED 305
5288 #define SSL_R_UNEXPECTED_COMPATIBILITY_MODE 306
5289 #define SSL_R_MISSING_ALPN 307
5290 #define SSL_R_NEGOTIATED_ALPS_WITHOUT_ALPN 308
5291 #define SSL_R_ALPS_MISMATCH_ON_EARLY_DATA 309
5292 #define SSL_R_SSLV3_ALERT_CLOSE_NOTIFY 1000
5293 #define SSL_R_SSLV3_ALERT_UNEXPECTED_MESSAGE 1010
5294 #define SSL_R_SSLV3_ALERT_BAD_RECORD_MAC 1020
5295 #define SSL_R_TLSV1_ALERT_DECRYPTION_FAILED 1021
5296 #define SSL_R_TLSV1_ALERT_RECORD_OVERFLOW 1022
5297 #define SSL_R_SSLV3_ALERT_DECOMPRESSION_FAILURE 1030
5298 #define SSL_R_SSLV3_ALERT_HANDSHAKE_FAILURE 1040
5299 #define SSL_R_SSLV3_ALERT_NO_CERTIFICATE 1041
5300 #define SSL_R_SSLV3_ALERT_BAD_CERTIFICATE 1042
5301 #define SSL_R_SSLV3_ALERT_UNSUPPORTED_CERTIFICATE 1043
5302 #define SSL_R_SSLV3_ALERT_CERTIFICATE_REVOKED 1044
5303 #define SSL_R_SSLV3_ALERT_CERTIFICATE_EXPIRED 1045
5304 #define SSL_R_SSLV3_ALERT_CERTIFICATE_UNKNOWN 1046
5305 #define SSL_R_SSLV3_ALERT_ILLEGAL_PARAMETER 1047
5306 #define SSL_R_TLSV1_ALERT_UNKNOWN_CA 1048
5307 #define SSL_R_TLSV1_ALERT_ACCESS_DENIED 1049
5308 #define SSL_R_TLSV1_ALERT_DECODE_ERROR 1050
5309 #define SSL_R_TLSV1_ALERT_DECRYPT_ERROR 1051
5310 #define SSL_R_TLSV1_ALERT_EXPORT_RESTRICTION 1060
5311 #define SSL_R_TLSV1_ALERT_PROTOCOL_VERSION 1070
5312 #define SSL_R_TLSV1_ALERT_INSUFFICIENT_SECURITY 1071
5313 #define SSL_R_TLSV1_ALERT_INTERNAL_ERROR 1080
5314 #define SSL_R_TLSV1_ALERT_INAPPROPRIATE_FALLBACK 1086
5315 #define SSL_R_TLSV1_ALERT_USER_CANCELLED 1090
5316 #define SSL_R_TLSV1_ALERT_NO_RENEGOTIATION 1100
5317 #define SSL_R_TLSV1_ALERT_UNSUPPORTED_EXTENSION 1110
5318 #define SSL_R_TLSV1_ALERT_CERTIFICATE_UNOBTAINABLE 1111
5319 #define SSL_R_TLSV1_ALERT_UNRECOGNIZED_NAME 1112
5320 #define SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_STATUS_RESPONSE 1113
5321 #define SSL_R_TLSV1_ALERT_BAD_CERTIFICATE_HASH_VALUE 1114
5322 #define SSL_R_TLSV1_ALERT_UNKNOWN_PSK_IDENTITY 1115
5323 #define SSL_R_TLSV1_ALERT_CERTIFICATE_REQUIRED 1116
5324 #define SSL_R_TLSV1_ALERT_NO_APPLICATION_PROTOCOL 1120
5325 
5326 #endif  // OPENSSL_HEADER_SSL_H
5327