. /include/boost/corosio /tls_context.hpp
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1   // 1   //
2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com) 2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   // Copyright (c) 2026 Michael Vandeberg 3   // Copyright (c) 2026 Michael Vandeberg
4   // 4   //
5   // Distributed under the Boost Software License, Version 1.0. (See accompanying 5   // Distributed under the Boost Software License, Version 1.0. (See accompanying
6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 6   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7   // 7   //
8   // Official repository: https://github.com/cppalliance/corosio 8   // Official repository: https://github.com/cppalliance/corosio
9   // 9   //
10   10  
11   #ifndef BOOST_COROSIO_TLS_CONTEXT_HPP 11   #ifndef BOOST_COROSIO_TLS_CONTEXT_HPP
12   #define BOOST_COROSIO_TLS_CONTEXT_HPP 12   #define BOOST_COROSIO_TLS_CONTEXT_HPP
13   13  
14   #include <boost/corosio/detail/config.hpp> 14   #include <boost/corosio/detail/config.hpp>
15   15  
16   #include <cstddef> 16   #include <cstddef>
17   #include <functional> 17   #include <functional>
18   #include <span> 18   #include <span>
19   #include <system_error> 19   #include <system_error>
20   #include <memory> 20   #include <memory>
21   #include <string_view> 21   #include <string_view>
22   22  
23   namespace boost::corosio { 23   namespace boost::corosio {
24   24  
25   // 25   //
26   // Enumerations 26   // Enumerations
27   // 27   //
28   28  
29   /** TLS protocol version. 29   /** TLS protocol version.
30   30  
31   Specifies the minimum or maximum TLS protocol version to use 31   Specifies the minimum or maximum TLS protocol version to use
32   for connections. Only modern, secure versions are supported. 32   for connections. Only modern, secure versions are supported.
33   33  
34   @see tls_context::set_min_protocol_version 34   @see tls_context::set_min_protocol_version
35   @see tls_context::set_max_protocol_version 35   @see tls_context::set_max_protocol_version
36   */ 36   */
37   enum class tls_version 37   enum class tls_version
38   { 38   {
39   /// TLS 1.2 (RFC 5246). 39   /// TLS 1.2 (RFC 5246).
40   tls_1_2, 40   tls_1_2,
41   41  
42   /// TLS 1.3 (RFC 8446). 42   /// TLS 1.3 (RFC 8446).
43   tls_1_3 43   tls_1_3
44   }; 44   };
45   45  
46   /** Certificate and key file format. 46   /** Certificate and key file format.
47   47  
48   Specifies the encoding format for certificate and key data. 48   Specifies the encoding format for certificate and key data.
49   49  
50   @see tls_context::use_certificate 50   @see tls_context::use_certificate
51   @see tls_context::use_private_key 51   @see tls_context::use_private_key
52   */ 52   */
53   enum class tls_file_format 53   enum class tls_file_format
54   { 54   {
55   /// PEM format (Base64-encoded with header/footer lines). 55   /// PEM format (Base64-encoded with header/footer lines).
56   pem, 56   pem,
57   57  
58   /// DER format (raw ASN.1 binary encoding). 58   /// DER format (raw ASN.1 binary encoding).
59   der 59   der
60   }; 60   };
61   61  
62   /** Peer certificate verification mode. 62   /** Peer certificate verification mode.
63   63  
64   Controls how the TLS implementation verifies the peer's 64   Controls how the TLS implementation verifies the peer's
65   certificate during the handshake. 65   certificate during the handshake.
66   66  
67   @see tls_context::set_verify_mode 67   @see tls_context::set_verify_mode
68   */ 68   */
69   enum class tls_verify_mode 69   enum class tls_verify_mode
70   { 70   {
71   /// Do not request or verify the peer certificate. 71   /// Do not request or verify the peer certificate.
72   none, 72   none,
73   73  
74   /// Request and verify the peer certificate if presented. 74   /// Request and verify the peer certificate if presented.
75   peer, 75   peer,
76   76  
77   /// Require and verify the peer certificate (fail if not presented). 77   /// Require and verify the peer certificate (fail if not presented).
78   require_peer 78   require_peer
79   }; 79   };
80   80  
81   /** Certificate revocation checking policy. 81   /** Certificate revocation checking policy.
82   82  
83   Controls how certificate revocation status is checked during 83   Controls how certificate revocation status is checked during
84   verification. 84   verification.
85   85  
86   @see tls_context::set_revocation_policy 86   @see tls_context::set_revocation_policy
87   */ 87   */
88   enum class tls_revocation_policy 88   enum class tls_revocation_policy
89   { 89   {
90   /// Do not check revocation status. 90   /// Do not check revocation status.
91   disabled, 91   disabled,
92   92  
93   /// Check revocation but allow connection if status is unknown. 93   /// Check revocation but allow connection if status is unknown.
94   soft_fail, 94   soft_fail,
95   95  
96   /// Require successful revocation check (fail if status is unknown). 96   /// Require successful revocation check (fail if status is unknown).
97   hard_fail 97   hard_fail
98   }; 98   };
99   99  
100   /** Purpose for password callback invocation. 100   /** Purpose for password callback invocation.
101   101  
102   Indicates whether the password is needed for reading (decrypting) 102   Indicates whether the password is needed for reading (decrypting)
103   or writing (encrypting) key material. 103   or writing (encrypting) key material.
104   104  
105   @see tls_context::set_password_callback 105   @see tls_context::set_password_callback
106   */ 106   */
107   enum class tls_password_purpose 107   enum class tls_password_purpose
108   { 108   {
109   /// Password needed to decrypt/read protected key material. 109   /// Password needed to decrypt/read protected key material.
110   for_reading, 110   for_reading,
111   111  
112   /// Password needed to encrypt/write protected key material. 112   /// Password needed to encrypt/write protected key material.
113   for_writing 113   for_writing
114   }; 114   };
115   115  
116   class tls_context; 116   class tls_context;
117   117  
118   /** A non-owning view of certificate verification state. 118   /** A non-owning view of certificate verification state.
119   119  
120   An instance is passed to the callback installed via 120   An instance is passed to the callback installed via
121   tls_context::set_verify_callback during the TLS handshake. It 121   tls_context::set_verify_callback during the TLS handshake. It
122   exposes the backend's native verification handle so the callback 122   exposes the backend's native verification handle so the callback
123   can inspect the certificate and chain currently being verified. 123   can inspect the certificate and chain currently being verified.
124   124  
125   The value returned by native_handle() is, for the OpenSSL and 125   The value returned by native_handle() is, for the OpenSSL and
126   WolfSSL backends, an `X509_STORE_CTX*`. For portable inspection that 126   WolfSSL backends, an `X509_STORE_CTX*`. For portable inspection that
127   works across backends (for example certificate pinning), prefer 127   works across backends (for example certificate pinning), prefer
128   certificate(), which returns the DER encoding of the certificate 128   certificate(), which returns the DER encoding of the certificate
129   currently being verified. 129   currently being verified.
130   130  
131   @par Lifetime 131   @par Lifetime
132   132  
133   The wrapped handle and the certificate() bytes are owned by the TLS 133   The wrapped handle and the certificate() bytes are owned by the TLS
134   backend and are valid only for the duration of a single callback 134   backend and are valid only for the duration of a single callback
135   invocation. Do not retain them beyond the call. 135   invocation. Do not retain them beyond the call.
136   136  
137   @see tls_context::set_verify_callback 137   @see tls_context::set_verify_callback
138   */ 138   */
139   class verify_context 139   class verify_context
140   { 140   {
141   void* handle_; 141   void* handle_;
142   unsigned char const* der_; 142   unsigned char const* der_;
143   std::size_t der_len_; 143   std::size_t der_len_;
144   144  
145   public: 145   public:
146   /** Construct from a native handle and the current certificate. 146   /** Construct from a native handle and the current certificate.
147   147  
148   @param handle The backend verification handle (for OpenSSL and 148   @param handle The backend verification handle (for OpenSSL and
149   WolfSSL, an `X509_STORE_CTX*`). 149   WolfSSL, an `X509_STORE_CTX*`).
150   @param der Pointer to the DER encoding of the certificate under 150   @param der Pointer to the DER encoding of the certificate under
151   verification, or `nullptr` if unavailable. 151   verification, or `nullptr` if unavailable.
152   @param der_len Length of the DER encoding in bytes. 152   @param der_len Length of the DER encoding in bytes.
153   */ 153   */
154   verify_context( 154   verify_context(
155   void* handle, unsigned char const* der, std::size_t der_len) noexcept 155   void* handle, unsigned char const* der, std::size_t der_len) noexcept
156   : handle_(handle) 156   : handle_(handle)
157   , der_(der) 157   , der_(der)
158   , der_len_(der_len) 158   , der_len_(der_len)
159   { 159   {
160   } 160   }
161   161  
162   /** Return the native verification handle. 162   /** Return the native verification handle.
163   163  
164   Cast the result to the backend's verification context type 164   Cast the result to the backend's verification context type
165   (e.g. `X509_STORE_CTX*`) to inspect the certificate chain using 165   (e.g. `X509_STORE_CTX*`) to inspect the certificate chain using
166   backend-specific APIs. 166   backend-specific APIs.
167   167  
168   @return The native handle, or `nullptr` if none is available. 168   @return The native handle, or `nullptr` if none is available.
169   */ 169   */
170   void* native_handle() const noexcept 170   void* native_handle() const noexcept
171   { 171   {
172   return handle_; 172   return handle_;
173   } 173   }
174   174  
175   /** Return the DER encoding of the certificate being verified. 175   /** Return the DER encoding of the certificate being verified.
176   176  
177   This is the portable way to inspect the peer certificate from a 177   This is the portable way to inspect the peer certificate from a
178   verification callback: it works identically on every backend, 178   verification callback: it works identically on every backend,
179   without depending on backend-specific build options. A DER 179   without depending on backend-specific build options. A DER
180   certificate is an ASN.1 `SEQUENCE`, so the first byte is `0x30`. 180   certificate is an ASN.1 `SEQUENCE`, so the first byte is `0x30`.
181   181  
182   @return A view of the certificate's DER bytes, valid only for the 182   @return A view of the certificate's DER bytes, valid only for the
183   duration of the callback. Empty if the certificate is not 183   duration of the callback. Empty if the certificate is not
184   available. 184   available.
185   */ 185   */
MISUBC 186   ✗ std::span<unsigned char const> certificate() const noexcept 186   ✗ std::span<unsigned char const> certificate() const noexcept
187   { 187   {
MISUBC 188   ✗ return {der_, der_len_}; 188   ✗ return {der_, der_len_};
189   } 189   }
190   }; 190   };
191   191  
192   namespace detail { 192   namespace detail {
193   struct tls_context_data; 193   struct tls_context_data;
194   tls_context_data const& get_tls_context_data(tls_context const&) noexcept; 194   tls_context_data const& get_tls_context_data(tls_context const&) noexcept;
195   } // namespace detail 195   } // namespace detail
196   196  
197   #ifdef _MSC_VER 197   #ifdef _MSC_VER
198   #pragma warning(push) 198   #pragma warning(push)
199   #pragma warning(disable : 4251) // shared_ptr needs dll-interface 199   #pragma warning(disable : 4251) // shared_ptr needs dll-interface
200   #endif 200   #endif
201   201  
202   /** A portable TLS context for certificate and settings storage. 202   /** A portable TLS context for certificate and settings storage.
203   203  
204   The `tls_context` class provides a backend-agnostic interface for 204   The `tls_context` class provides a backend-agnostic interface for
205   configuring TLS connections. It stores credentials (certificates and 205   configuring TLS connections. It stores credentials (certificates and
206   private keys), trust anchors, protocol settings, and verification 206   private keys), trust anchors, protocol settings, and verification
207   options that are used when establishing TLS connections. 207   options that are used when establishing TLS connections.
208   208  
209   This class is a shared handle to an opaque implementation. Copies 209   This class is a shared handle to an opaque implementation. Copies
210   share the same underlying state. This allows contexts to be passed 210   share the same underlying state. This allows contexts to be passed
211   by value and shared across multiple TLS streams. 211   by value and shared across multiple TLS streams.
212   212  
213   This class abstracts the configuration phase of TLS across multiple 213   This class abstracts the configuration phase of TLS across multiple
214   backend implementations (OpenSSL, WolfSSL, mbedTLS, Schannel, etc.), 214   backend implementations (OpenSSL, WolfSSL, mbedTLS, Schannel, etc.),
215   allowing portable code that works regardless of which TLS library 215   allowing portable code that works regardless of which TLS library
216   is linked. 216   is linked.
217   217  
218   @par Modification After Stream Creation 218   @par Modification After Stream Creation
219   219  
220   Modifying a context after a TLS stream has been created from it 220   Modifying a context after a TLS stream has been created from it
221   results in undefined behavior. The context's configuration is 221   results in undefined behavior. The context's configuration is
222   captured when the first stream is constructed, and subsequent 222   captured when the first stream is constructed, and subsequent
223   modifications are not reflected in existing or new streams 223   modifications are not reflected in existing or new streams
224   sharing the context. 224   sharing the context.
225   225  
226   If different configurations are needed, create separate context 226   If different configurations are needed, create separate context
227   objects. 227   objects.
228   228  
229   @par Thread Safety 229   @par Thread Safety
230   230  
231   Distinct objects: Safe. 231   Distinct objects: Safe.
232   232  
233   Shared objects: Unsafe. A context must not be modified while 233   Shared objects: Unsafe. A context must not be modified while
234   any thread is creating streams from it. 234   any thread is creating streams from it.
235   235  
236   @par Example 236   @par Example
237   @par !example tls_context 237   @par !example tls_context
238   238  
239   @see tls_role 239   @see tls_role
240   */ 240   */
241   class BOOST_COROSIO_DECL tls_context 241   class BOOST_COROSIO_DECL tls_context
242   { 242   {
243   struct implementation; 243   struct implementation;
244   std::shared_ptr<implementation> impl_; 244   std::shared_ptr<implementation> impl_;
245   245  
246   friend detail::tls_context_data const& 246   friend detail::tls_context_data const&
247   detail::get_tls_context_data(tls_context const&) noexcept; 247   detail::get_tls_context_data(tls_context const&) noexcept;
248   248  
249   public: 249   public:
250   /** Construct a default TLS context. 250   /** Construct a default TLS context.
251   251  
252   Creates a context with default settings suitable for TLS 1.2 252   Creates a context with default settings suitable for TLS 1.2
253   and TLS 1.3 connections. No certificates or trust anchors are 253   and TLS 1.3 connections. No certificates or trust anchors are
254   loaded; call the appropriate methods to configure credentials 254   loaded; call the appropriate methods to configure credentials
255   and verification. 255   and verification.
256   256  
257   @par Example 257   @par Example
258   @par !example tls_context 258   @par !example tls_context
259   */ 259   */
260   tls_context(); 260   tls_context();
261   261  
262   /** Copy constructor. 262   /** Copy constructor.
263   263  
264   Creates a new handle that shares ownership of the underlying 264   Creates a new handle that shares ownership of the underlying
265   TLS context state with `other`. 265   TLS context state with `other`.
266   266  
267   @param other The context to copy from. 267   @param other The context to copy from.
268   */ 268   */
HITCBC 269   2 tls_context(tls_context const& other) = default; 269   2 tls_context(tls_context const& other) = default;
270   270  
271   /** Copy assignment operator. 271   /** Copy assignment operator.
272   272  
273   Releases the current context's shared ownership and acquires 273   Releases the current context's shared ownership and acquires
274   shared ownership of `other`'s underlying state. 274   shared ownership of `other`'s underlying state.
275   275  
276   @param other The context to copy from. 276   @param other The context to copy from.
277   277  
278   @return Reference to this context. 278   @return Reference to this context.
279   */ 279   */
HITCBC 280   1 tls_context& operator=(tls_context const& other) = default; 280   1 tls_context& operator=(tls_context const& other) = default;
281   281  
282   /** Move constructor. 282   /** Move constructor.
283   283  
284   Transfers ownership of the TLS context from another instance. 284   Transfers ownership of the TLS context from another instance.
285   After the move, `other` is in a valid but empty state. 285   After the move, `other` is in a valid but empty state.
286   286  
287   @param other The context to move from. 287   @param other The context to move from.
288   */ 288   */
HITCBC 289   2 tls_context(tls_context&& other) noexcept = default; 289   2 tls_context(tls_context&& other) noexcept = default;
290   290  
291   /** Move assignment operator. 291   /** Move assignment operator.
292   292  
293   Releases the current context's shared ownership and transfers 293   Releases the current context's shared ownership and transfers
294   ownership from another instance. After the move, `other` is 294   ownership from another instance. After the move, `other` is
295   in a valid but empty state. 295   in a valid but empty state.
296   296  
297   @param other The context to move from. 297   @param other The context to move from.
298   298  
299   @return Reference to this context. 299   @return Reference to this context.
300   */ 300   */
HITCBC 301   1 tls_context& operator=(tls_context&& other) noexcept = default; 301   1 tls_context& operator=(tls_context&& other) noexcept = default;
302   302  
303   /** Destructor. 303   /** Destructor.
304   304  
305   Releases this handle's shared ownership of the underlying 305   Releases this handle's shared ownership of the underlying
306   context. The context state is destroyed when the last handle 306   context. The context state is destroyed when the last handle
307   is released. 307   is released.
308   */ 308   */
HITCBC 309   55 ~tls_context() = default; 309   55 ~tls_context() = default;
310   310  
311   // 311   //
312   // Credential Loading 312   // Credential Loading
313   // 313   //
314   314  
315   /** Load the entity certificate from a memory buffer. 315   /** Load the entity certificate from a memory buffer.
316   316  
317   Sets the certificate that identifies this endpoint to the peer. 317   Sets the certificate that identifies this endpoint to the peer.
318   For servers, this is the server certificate. For clients using 318   For servers, this is the server certificate. For clients using
319   mutual TLS, this is the client certificate. 319   mutual TLS, this is the client certificate.
320   320  
321   The certificate must match the private key loaded via 321   The certificate must match the private key loaded via
322   `use_private_key()` or `use_private_key_file()`. 322   `use_private_key()` or `use_private_key_file()`.
323   323  
324   @param certificate The certificate data. 324   @param certificate The certificate data.
325   325  
326   @param format The encoding format of the certificate data. 326   @param format The encoding format of the certificate data.
327   327  
328   @return Success. The certificate is recorded and decoded when the 328   @return Success. The certificate is recorded and decoded when the
329   native context is first built; a malformed certificate surfaces 329   native context is first built; a malformed certificate surfaces
330   as a handshake failure. 330   as a handshake failure.
331   331  
332   @see use_certificate_file 332   @see use_certificate_file
333   @see use_private_key 333   @see use_private_key
334   */ 334   */
335   [[nodiscard]] std::error_code 335   [[nodiscard]] std::error_code
336   use_certificate(std::string_view certificate, tls_file_format format); 336   use_certificate(std::string_view certificate, tls_file_format format);
337   337  
338   /** Load the entity certificate from a file. 338   /** Load the entity certificate from a file.
339   339  
340   Sets the certificate that identifies this endpoint to the peer. 340   Sets the certificate that identifies this endpoint to the peer.
341   For servers, this is the server certificate. For clients using 341   For servers, this is the server certificate. For clients using
342   mutual TLS, this is the client certificate. 342   mutual TLS, this is the client certificate.
343   343  
344   @param filename Path to the certificate file. 344   @param filename Path to the certificate file.
345   345  
346   @param format The encoding format of the file. 346   @param format The encoding format of the file.
347   347  
348   @return Success, or an error if the file could not be read. The 348   @return Success, or an error if the file could not be read. The
349   certificate is decoded when the native context is first built; 349   certificate is decoded when the native context is first built;
350   a malformed certificate surfaces as a handshake failure. 350   a malformed certificate surfaces as a handshake failure.
351   351  
352   @par Example 352   @par Example
353   @par !example use_certificate_file 353   @par !example use_certificate_file
354   354  
355   @see use_certificate 355   @see use_certificate
356   @see use_private_key_file 356   @see use_private_key_file
357   */ 357   */
358   [[nodiscard]] std::error_code 358   [[nodiscard]] std::error_code
359   use_certificate_file(std::string_view filename, tls_file_format format); 359   use_certificate_file(std::string_view filename, tls_file_format format);
360   360  
361   /** Load a certificate chain from a memory buffer. 361   /** Load a certificate chain from a memory buffer.
362   362  
363   Loads the entity certificate followed by intermediate CA certificates. 363   Loads the entity certificate followed by intermediate CA certificates.
364   The chain should be ordered from leaf to root (excluding the root). 364   The chain should be ordered from leaf to root (excluding the root).
365   This is the typical format for PEM certificate bundles. 365   This is the typical format for PEM certificate bundles.
366   366  
367   @param chain The certificate chain data in PEM format (concatenated 367   @param chain The certificate chain data in PEM format (concatenated
368   certificates). 368   certificates).
369   369  
370   @return Success. The chain is recorded and decoded when the native 370   @return Success. The chain is recorded and decoded when the native
371   context is first built; a malformed chain surfaces as a 371   context is first built; a malformed chain surfaces as a
372   handshake failure. 372   handshake failure.
373   373  
374   @see use_certificate_chain_file 374   @see use_certificate_chain_file
375   */ 375   */
376   [[nodiscard]] std::error_code use_certificate_chain(std::string_view chain); 376   [[nodiscard]] std::error_code use_certificate_chain(std::string_view chain);
377   377  
378   /** Load a certificate chain from a file. 378   /** Load a certificate chain from a file.
379   379  
380   Loads the entity certificate followed by intermediate CA certificates 380   Loads the entity certificate followed by intermediate CA certificates
381   from a PEM file. The file should contain concatenated PEM certificates 381   from a PEM file. The file should contain concatenated PEM certificates
382   ordered from leaf to root (excluding the root). 382   ordered from leaf to root (excluding the root).
383   383  
384   @param filename Path to the certificate chain file. 384   @param filename Path to the certificate chain file.
385   385  
386   @return Success, or an error if the file could not be read. The 386   @return Success, or an error if the file could not be read. The
387   chain is decoded when the native context is first built; a 387   chain is decoded when the native context is first built; a
388   malformed chain surfaces as a handshake failure. 388   malformed chain surfaces as a handshake failure.
389   389  
390   @par Example 390   @par Example
391   @par !example use_certificate_chain_file 391   @par !example use_certificate_chain_file
392   392  
393   @see use_certificate_chain 393   @see use_certificate_chain
394   */ 394   */
395   [[nodiscard]] std::error_code 395   [[nodiscard]] std::error_code
396   use_certificate_chain_file(std::string_view filename); 396   use_certificate_chain_file(std::string_view filename);
397   397  
398   /** Load the private key from a memory buffer. 398   /** Load the private key from a memory buffer.
399   399  
400   Sets the private key corresponding to the entity certificate. 400   Sets the private key corresponding to the entity certificate.
401   The key must match the certificate loaded via `use_certificate()` 401   The key must match the certificate loaded via `use_certificate()`
402   or `use_certificate_chain()`. 402   or `use_certificate_chain()`.
403   403  
404   If the key is encrypted, set a password callback via 404   If the key is encrypted, set a password callback via
405   `set_password_callback()` before calling this function. 405   `set_password_callback()` before calling this function.
406   406  
407   @param private_key The private key data. 407   @param private_key The private key data.
408   408  
409   @param format The encoding format of the key data. 409   @param format The encoding format of the key data.
410   410  
411   @return Success. The key is recorded and decoded when the native 411   @return Success. The key is recorded and decoded when the native
412   context is first built; a malformed key, a missing password 412   context is first built; a malformed key, a missing password
413   callback for an encrypted key, or a certificate mismatch 413   callback for an encrypted key, or a certificate mismatch
414   surfaces as a handshake failure. 414   surfaces as a handshake failure.
415   415  
416   @see use_private_key_file 416   @see use_private_key_file
417   @see set_password_callback 417   @see set_password_callback
418   */ 418   */
419   [[nodiscard]] std::error_code 419   [[nodiscard]] std::error_code
420   use_private_key(std::string_view private_key, tls_file_format format); 420   use_private_key(std::string_view private_key, tls_file_format format);
421   421  
422   /** Load the private key from a file. 422   /** Load the private key from a file.
423   423  
424   Sets the private key corresponding to the entity certificate. 424   Sets the private key corresponding to the entity certificate.
425   The key must match the certificate loaded via `use_certificate_file()` 425   The key must match the certificate loaded via `use_certificate_file()`
426   or `use_certificate_chain_file()`. 426   or `use_certificate_chain_file()`.
427   427  
428   If the key file is encrypted, set a password callback via 428   If the key file is encrypted, set a password callback via
429   `set_password_callback()` before calling this function. 429   `set_password_callback()` before calling this function.
430   430  
431   @param filename Path to the private key file. 431   @param filename Path to the private key file.
432   432  
433   @param format The encoding format of the file. 433   @param format The encoding format of the file.
434   434  
435   @return Success, or an error if the file could not be read. The 435   @return Success, or an error if the file could not be read. The
436   key is decoded when the native context is first built; a 436   key is decoded when the native context is first built; a
437   malformed key or a certificate mismatch surfaces as a 437   malformed key or a certificate mismatch surfaces as a
438   handshake failure. 438   handshake failure.
439   439  
440   @par Example 440   @par Example
441   @par !example use_private_key_file 441   @par !example use_private_key_file
442   442  
443   @see use_private_key 443   @see use_private_key
444   @see set_password_callback 444   @see set_password_callback
445   */ 445   */
446   [[nodiscard]] std::error_code 446   [[nodiscard]] std::error_code
447   use_private_key_file(std::string_view filename, tls_file_format format); 447   use_private_key_file(std::string_view filename, tls_file_format format);
448   448  
449   /** Load credentials from a PKCS#12 bundle in memory. 449   /** Load credentials from a PKCS#12 bundle in memory.
450   450  
451   PKCS#12 (also known as PFX) is a binary format that bundles a 451   PKCS#12 (also known as PFX) is a binary format that bundles a
452   certificate, private key, and optionally intermediate certificates 452   certificate, private key, and optionally intermediate certificates
453   into a single password-protected file. 453   into a single password-protected file.
454   454  
455   @param data The PKCS#12 bundle data. 455   @param data The PKCS#12 bundle data.
456   456  
457   @param passphrase The password protecting the bundle. 457   @param passphrase The password protecting the bundle.
458   458  
459   @return Success. The bundle is recorded and decoded into the 459   @return Success. The bundle is recorded and decoded into the
460   certificate, private key, and chain when the native context is 460   certificate, private key, and chain when the native context is
461   first built; a malformed bundle or wrong passphrase surfaces as 461   first built; a malformed bundle or wrong passphrase surfaces as
462   a handshake failure. 462   a handshake failure.
463   463  
464   @note Intermediate certificates inside the bundle are loaded and 464   @note Intermediate certificates inside the bundle are loaded and
465   sent during the handshake on both backends. 465   sent during the handshake on both backends.
466   466  
467   @see use_pkcs12_file 467   @see use_pkcs12_file
468   */ 468   */
469   [[nodiscard]] std::error_code 469   [[nodiscard]] std::error_code
470   use_pkcs12(std::string_view data, std::string_view passphrase); 470   use_pkcs12(std::string_view data, std::string_view passphrase);
471   471  
472   /** Load credentials from a PKCS#12 file. 472   /** Load credentials from a PKCS#12 file.
473   473  
474   PKCS#12 (also known as PFX) is a binary format that bundles a 474   PKCS#12 (also known as PFX) is a binary format that bundles a
475   certificate, private key, and optionally intermediate certificates 475   certificate, private key, and optionally intermediate certificates
476   into a single password-protected file. This is common on Windows 476   into a single password-protected file. This is common on Windows
477   and for certificates exported from browsers. 477   and for certificates exported from browsers.
478   478  
479   @param filename Path to the PKCS#12 file. 479   @param filename Path to the PKCS#12 file.
480   480  
481   @param passphrase The password protecting the file. 481   @param passphrase The password protecting the file.
482   482  
483   @return Success, or an error if the file could not be read. The 483   @return Success, or an error if the file could not be read. The
484   bundle is decoded when the native context is first built; a 484   bundle is decoded when the native context is first built; a
485   malformed bundle or wrong passphrase surfaces as a handshake 485   malformed bundle or wrong passphrase surfaces as a handshake
486   failure. 486   failure.
487   487  
488   @note Intermediate certificates inside the bundle are loaded and 488   @note Intermediate certificates inside the bundle are loaded and
489   sent during the handshake on both backends. 489   sent during the handshake on both backends.
490   490  
491   @par Example 491   @par Example
492   @par !example use_pkcs12_file 492   @par !example use_pkcs12_file
493   493  
494   @see use_pkcs12 494   @see use_pkcs12
495   */ 495   */
496   [[nodiscard]] std::error_code 496   [[nodiscard]] std::error_code
497   use_pkcs12_file(std::string_view filename, std::string_view passphrase); 497   use_pkcs12_file(std::string_view filename, std::string_view passphrase);
498   498  
499   // 499   //
500   // Trust Anchors 500   // Trust Anchors
501   // 501   //
502   502  
503   /** Add a certificate authority for peer verification. 503   /** Add a certificate authority for peer verification.
504   504  
505   Adds a single CA certificate to the trust store used for verifying 505   Adds a single CA certificate to the trust store used for verifying
506   peer certificates. Call this multiple times to add multiple CAs, 506   peer certificates. Call this multiple times to add multiple CAs,
507   or use `load_verify_file()` for a bundle. 507   or use `load_verify_file()` for a bundle.
508   508  
509   @param ca The CA certificate data in PEM format. 509   @param ca The CA certificate data in PEM format.
510   510  
511   @return Success. The certificate is recorded and decoded when the 511   @return Success. The certificate is recorded and decoded when the
512   native context is first built; a malformed certificate 512   native context is first built; a malformed certificate
513   surfaces as a handshake failure. 513   surfaces as a handshake failure.
514   514  
515   @see load_verify_file 515   @see load_verify_file
516   @see set_default_verify_paths 516   @see set_default_verify_paths
517   */ 517   */
518   [[nodiscard]] std::error_code 518   [[nodiscard]] std::error_code
519   add_certificate_authority(std::string_view ca); 519   add_certificate_authority(std::string_view ca);
520   520  
521   /** Load CA certificates from a file. 521   /** Load CA certificates from a file.
522   522  
523   Loads one or more CA certificates from a PEM file. The file may 523   Loads one or more CA certificates from a PEM file. The file may
524   contain multiple concatenated PEM certificates. 524   contain multiple concatenated PEM certificates.
525   525  
526   @param filename Path to a PEM file containing CA certificates. 526   @param filename Path to a PEM file containing CA certificates.
527   527  
528   @return Success, or an error if the file could not be read. The 528   @return Success, or an error if the file could not be read. The
529   certificates are decoded when the native context is first 529   certificates are decoded when the native context is first
530   built; malformed certificates surface as a handshake failure. 530   built; malformed certificates surface as a handshake failure.
531   531  
532   @par Example 532   @par Example
533   @par !example load_verify_file 533   @par !example load_verify_file
534   534  
535   @see add_certificate_authority 535   @see add_certificate_authority
536   @see add_verify_path 536   @see add_verify_path
537   */ 537   */
538   [[nodiscard]] std::error_code load_verify_file(std::string_view filename); 538   [[nodiscard]] std::error_code load_verify_file(std::string_view filename);
539   539  
540   /** Add a directory of CA certificates for verification. 540   /** Add a directory of CA certificates for verification.
541   541  
542   Adds a directory of CA certificates to the trust store. The 542   Adds a directory of CA certificates to the trust store. The
543   directory is applied when the native context is first built from 543   directory is applied when the native context is first built from
544   this context. 544   this context.
545   545  
546   The expected directory layout depends on the backend. OpenSSL 546   The expected directory layout depends on the backend. OpenSSL
547   performs on-demand lookups and requires each certificate file to 547   performs on-demand lookups and requires each certificate file to
548   be named by its subject-name hash (as generated by 548   be named by its subject-name hash (as generated by
549   `openssl rehash` or `c_rehash`); WolfSSL loads every certificate 549   `openssl rehash` or `c_rehash`); WolfSSL loads every certificate
550   file in the directory. 550   file in the directory.
551   551  
552   @param path Path to the directory of CA certificates. 552   @param path Path to the directory of CA certificates.
553   553  
554   @return Success. The path is recorded and applied when the native 554   @return Success. The path is recorded and applied when the native
555   context is built; a directory that cannot be read at that time 555   context is built; a directory that cannot be read at that time
556   is skipped rather than reported here. 556   is skipped rather than reported here.
557   557  
558   @par Example 558   @par Example
559   @par !example add_verify_path 559   @par !example add_verify_path
560   560  
561   @see load_verify_file 561   @see load_verify_file
562   @see set_default_verify_paths 562   @see set_default_verify_paths
563   */ 563   */
564   [[nodiscard]] std::error_code add_verify_path(std::string_view path); 564   [[nodiscard]] std::error_code add_verify_path(std::string_view path);
565   565  
566   /** Use the system default CA certificate store. 566   /** Use the system default CA certificate store.
567   567  
568   Configures the context to use the operating system's default 568   Configures the context to use the operating system's default
569   trust store for peer certificate verification. This is the 569   trust store for peer certificate verification. This is the
570   recommended approach for HTTPS clients connecting to public 570   recommended approach for HTTPS clients connecting to public
571   servers. 571   servers.
572   572  
573   The system store is loaded when the native context is first built 573   The system store is loaded when the native context is first built
574   from this context. For a verified-safe client, combine this with 574   from this context. For a verified-safe client, combine this with
575   `set_verify_mode( tls_verify_mode::peer )` and, when connecting by 575   `set_verify_mode( tls_verify_mode::peer )` and, when connecting by
576   name, `tls_stream::set_hostname()`. 576   name, `tls_stream::set_hostname()`.
577   577  
578   @return Success. The request is recorded and applied when the 578   @return Success. The request is recorded and applied when the
579   native context is built; if the system store cannot be loaded 579   native context is built; if the system store cannot be loaded
580   at that time it is skipped rather than reported here, so a 580   at that time it is skipped rather than reported here, so a
581   context that must reject unverified peers should also use 581   context that must reject unverified peers should also use
582   `set_verify_mode( tls_verify_mode::peer )`. 582   `set_verify_mode( tls_verify_mode::peer )`.
583   583  
584   @note The OpenSSL backend honors the `SSL_CERT_FILE` and 584   @note The OpenSSL backend honors the `SSL_CERT_FILE` and
585   `SSL_CERT_DIR` environment variables. The WolfSSL backend 585   `SSL_CERT_DIR` environment variables. The WolfSSL backend
586   requires a build with `WOLFSSL_SYS_CA_CERTS`; without it the 586   requires a build with `WOLFSSL_SYS_CA_CERTS`; without it the
587   system store is unavailable and this call has no effect. 587   system store is unavailable and this call has no effect.
588   588  
589   @par Example 589   @par Example
590   @par !example set_default_verify_paths 590   @par !example set_default_verify_paths
591   591  
592   @see load_verify_file 592   @see load_verify_file
593   @see add_verify_path 593   @see add_verify_path
594   @see set_verify_mode 594   @see set_verify_mode
595   */ 595   */
596   [[nodiscard]] std::error_code set_default_verify_paths(); 596   [[nodiscard]] std::error_code set_default_verify_paths();
597   597  
598   // 598   //
599   // Protocol Configuration 599   // Protocol Configuration
600   // 600   //
601   601  
602   /** Set the minimum TLS protocol version. 602   /** Set the minimum TLS protocol version.
603   603  
604   Connections will reject protocol versions older than this. 604   Connections will reject protocol versions older than this.
605   The default allows TLS 1.2 and newer. 605   The default allows TLS 1.2 and newer.
606   606  
607   @param v The minimum protocol version to accept. 607   @param v The minimum protocol version to accept.
608   608  
609   @return Success. The version is recorded and applied when the 609   @return Success. The version is recorded and applied when the
610   native context is first built. 610   native context is first built.
611   611  
612   @par Example 612   @par Example
613   @par !example set_min_protocol_version 613   @par !example set_min_protocol_version
614   614  
615   @see set_max_protocol_version 615   @see set_max_protocol_version
616   */ 616   */
617   [[nodiscard]] std::error_code set_min_protocol_version(tls_version v); 617   [[nodiscard]] std::error_code set_min_protocol_version(tls_version v);
618   618  
619   /** Set the maximum TLS protocol version. 619   /** Set the maximum TLS protocol version.
620   620  
621   Connections will not negotiate protocol versions newer than this. 621   Connections will not negotiate protocol versions newer than this.
622   The default allows the newest supported version. 622   The default allows the newest supported version.
623   623  
624   @param v The maximum protocol version to accept. 624   @param v The maximum protocol version to accept.
625   625  
626   @return Success. The version is recorded and applied when the 626   @return Success. The version is recorded and applied when the
627   native context is first built. 627   native context is first built.
628   628  
629   @note On WolfSSL the ceiling is applied by selecting a 629   @note On WolfSSL the ceiling is applied by selecting a
630   version-specific method (no native set-max API exists); an 630   version-specific method (no native set-max API exists); an
631   invalid window where the minimum exceeds the maximum yields a 631   invalid window where the minimum exceeds the maximum yields a
632   context that fails the handshake. 632   context that fails the handshake.
633   633  
634   @see set_min_protocol_version 634   @see set_min_protocol_version
635   */ 635   */
636   [[nodiscard]] std::error_code set_max_protocol_version(tls_version v); 636   [[nodiscard]] std::error_code set_max_protocol_version(tls_version v);
637   637  
638   /** Set the allowed cipher suites. 638   /** Set the allowed cipher suites.
639   639  
640   Configures which cipher suites may be used for connections. 640   Configures which cipher suites may be used for connections.
641   The format is backend-specific but typically follows OpenSSL 641   The format is backend-specific but typically follows OpenSSL
642   cipher list syntax. 642   cipher list syntax.
643   643  
644   @param ciphers The cipher suite specification string. 644   @param ciphers The cipher suite specification string.
645   645  
646   @return Success. The string is recorded and applied when the 646   @return Success. The string is recorded and applied when the
647   native context is first built; an invalid cipher string 647   native context is first built; an invalid cipher string
648   surfaces as a handshake failure. 648   surfaces as a handshake failure.
649   649  
650   @par Example 650   @par Example
651   @par !example set_ciphersuites 651   @par !example set_ciphersuites
652   652  
653   @note This configures cipher suites for TLS 1.2 and below. For 653   @note This configures cipher suites for TLS 1.2 and below. For
654   TLS 1.3, use @ref set_ciphersuites_tls13. 654   TLS 1.3, use @ref set_ciphersuites_tls13.
655   */ 655   */
656   [[nodiscard]] std::error_code set_ciphersuites(std::string_view ciphers); 656   [[nodiscard]] std::error_code set_ciphersuites(std::string_view ciphers);
657   657  
658   /** Set the allowed TLS 1.3 cipher suites. 658   /** Set the allowed TLS 1.3 cipher suites.
659   659  
660   TLS 1.3 uses a distinct, fixed set of cipher suites configured 660   TLS 1.3 uses a distinct, fixed set of cipher suites configured
661   separately from earlier versions. The format is a colon-separated 661   separately from earlier versions. The format is a colon-separated
662   list of TLS 1.3 suite names. 662   list of TLS 1.3 suite names.
663   663  
664   @param ciphers The TLS 1.3 cipher suite list. 664   @param ciphers The TLS 1.3 cipher suite list.
665   665  
666   @return Success. The string is recorded and applied when the 666   @return Success. The string is recorded and applied when the
667   native context is first built; an invalid cipher string 667   native context is first built; an invalid cipher string
668   surfaces as a handshake failure. 668   surfaces as a handshake failure.
669   669  
670   @par Example 670   @par Example
671   @par !example set_ciphersuites_tls13 671   @par !example set_ciphersuites_tls13
672   672  
673   @note On the WolfSSL backend, TLS 1.2 and TLS 1.3 suites share a 673   @note On the WolfSSL backend, TLS 1.2 and TLS 1.3 suites share a
674   single cipher list; this call and @ref set_ciphersuites are 674   single cipher list; this call and @ref set_ciphersuites are
675   merged into one list. 675   merged into one list.
676   676  
677   @see set_ciphersuites 677   @see set_ciphersuites
678   */ 678   */
679   [[nodiscard]] std::error_code 679   [[nodiscard]] std::error_code
680   set_ciphersuites_tls13(std::string_view ciphers); 680   set_ciphersuites_tls13(std::string_view ciphers);
681   681  
682   /** Set the ALPN protocol list. 682   /** Set the ALPN protocol list.
683   683  
684   Configures Application-Layer Protocol Negotiation (ALPN) for 684   Configures Application-Layer Protocol Negotiation (ALPN) for
685   the connection. ALPN is used to negotiate which application 685   the connection. ALPN is used to negotiate which application
686   protocol to use over the TLS connection (e.g., "h2" for HTTP/2, 686   protocol to use over the TLS connection (e.g., "h2" for HTTP/2,
687   "http/1.1" for HTTP/1.1). 687   "http/1.1" for HTTP/1.1).
688   688  
689   The protocols are tried in preference order (first = highest). 689   The protocols are tried in preference order (first = highest).
690   690  
691   @param protocols Ordered list of protocol identifiers. 691   @param protocols Ordered list of protocol identifiers.
692   692  
693   @return Success, or an error if ALPN configuration fails. 693   @return Success, or an error if ALPN configuration fails.
694   694  
695   @note Read the negotiated protocol after the handshake via 695   @note Read the negotiated protocol after the handshake via
696   @ref tls_stream::alpn_protocol. On WolfSSL, ALPN requires a 696   @ref tls_stream::alpn_protocol. On WolfSSL, ALPN requires a
697   build with `HAVE_ALPN`; without it, offering protocols fails 697   build with `HAVE_ALPN`; without it, offering protocols fails
698   the handshake with `std::errc::function_not_supported` rather 698   the handshake with `std::errc::function_not_supported` rather
699   than negotiate nothing silently. 699   than negotiate nothing silently.
700   700  
701   @par Example 701   @par Example
702   @par !example set_alpn 702   @par !example set_alpn
703   */ 703   */
704   [[nodiscard]] std::error_code 704   [[nodiscard]] std::error_code
705   set_alpn(std::initializer_list<std::string_view> protocols); 705   set_alpn(std::initializer_list<std::string_view> protocols);
706   706  
707   // 707   //
708   // Certificate Verification 708   // Certificate Verification
709   // 709   //
710   710  
711   /** Set the peer certificate verification mode. 711   /** Set the peer certificate verification mode.
712   712  
713   Controls whether and how peer certificates are verified during 713   Controls whether and how peer certificates are verified during
714   the TLS handshake. 714   the TLS handshake.
715   715  
716   @param mode The verification mode to use. 716   @param mode The verification mode to use.
717   717  
718   @return Success. The mode is recorded and applied when the native 718   @return Success. The mode is recorded and applied when the native
719   context is first built. 719   context is first built.
720   720  
721   @par Example 721   @par Example
722   @par !example set_verify_mode 722   @par !example set_verify_mode
723   723  
724   @see tls_verify_mode 724   @see tls_verify_mode
725   */ 725   */
726   [[nodiscard]] std::error_code set_verify_mode(tls_verify_mode mode); 726   [[nodiscard]] std::error_code set_verify_mode(tls_verify_mode mode);
727   727  
728   /** Set the maximum certificate chain verification depth. 728   /** Set the maximum certificate chain verification depth.
729   729  
730   Limits how many intermediate certificates can appear between 730   Limits how many intermediate certificates can appear between
731   the peer certificate and a trusted root. The default is 731   the peer certificate and a trusted root. The default is
732   typically 100, which is sufficient for most certificate chains. 732   typically 100, which is sufficient for most certificate chains.
733   733  
734   @param depth Maximum number of intermediate certificates allowed. 734   @param depth Maximum number of intermediate certificates allowed.
735   735  
736   @return Success. The depth is recorded and applied when the native 736   @return Success. The depth is recorded and applied when the native
737   context is first built. 737   context is first built.
738   */ 738   */
739   [[nodiscard]] std::error_code set_verify_depth(int depth); 739   [[nodiscard]] std::error_code set_verify_depth(int depth);
740   740  
741   /** Set a custom certificate verification callback. 741   /** Set a custom certificate verification callback.
742   742  
743   Installs a callback that is invoked during certificate chain 743   Installs a callback that is invoked during certificate chain
744   verification. The callback can perform additional validation 744   verification. The callback can perform additional validation
745   beyond the standard checks and can override verification 745   beyond the standard checks and can override verification
746   results. 746   results.
747   747  
748   The callback receives the built-in verification result so far and 748   The callback receives the built-in verification result so far and
749   a verify_context describing the certificate being verified. Return 749   a verify_context describing the certificate being verified. Return
750   `true` to accept the certificate, `false` to reject. Inspect the 750   `true` to accept the certificate, `false` to reject. Inspect the
751   certificate portably via `verify_context::certificate()` (its DER 751   certificate portably via `verify_context::certificate()` (its DER
752   encoding) — for example to pin a specific certificate. 752   encoding) — for example to pin a specific certificate.
753   753  
754   @par Backend Support 754   @par Backend Support
755   755  
756   The exact set of certificates the callback sees differs by backend: 756   The exact set of certificates the callback sees differs by backend:
757   757  
758   - OpenSSL: the callback runs once per certificate in the chain, 758   - OpenSSL: the callback runs once per certificate in the chain,
759   including certificates that passed the built-in checks. It can 759   including certificates that passed the built-in checks. It can
760   therefore both relax verification (return `true` for a 760   therefore both relax verification (return `true` for a
761   certificate the library rejected) and tighten it (return `false` 761   certificate the library rejected) and tighten it (return `false`
762   for a certificate the library accepted, e.g. pinning). 762   for a certificate the library accepted, e.g. pinning).
763   - WolfSSL built with `WOLFSSL_ALWAYS_VERIFY_CB` (implied by 763   - WolfSSL built with `WOLFSSL_ALWAYS_VERIFY_CB` (implied by
764   `--enable-opensslextra`): same as OpenSSL. 764   `--enable-opensslextra`): same as OpenSSL.
765   - WolfSSL without that option: the library invokes the callback 765   - WolfSSL without that option: the library invokes the callback
766   only on verification *failure*, so it cannot be honored on a 766   only on verification *failure*, so it cannot be honored on a
767   successful handshake. To avoid silently ignoring a 767   successful handshake. To avoid silently ignoring a
768   verification-tightening callback (which would fail open), a 768   verification-tightening callback (which would fail open), a
769   context that carries a callback instead **fails the handshake** 769   context that carries a callback instead **fails the handshake**
770   with `std::errc::function_not_supported` on such a build. Rebuild 770   with `std::errc::function_not_supported` on such a build. Rebuild
771   WolfSSL with `WOLFSSL_ALWAYS_VERIFY_CB`, or omit the callback. 771   WolfSSL with `WOLFSSL_ALWAYS_VERIFY_CB`, or omit the callback.
772   772  
773   @tparam Callback A callable with signature 773   @tparam Callback A callable with signature
774   `bool( bool preverified, verify_context& ctx )`. 774   `bool( bool preverified, verify_context& ctx )`.
775   775  
776   @param callback The verification callback. Recorded here and 776   @param callback The verification callback. Recorded here and
777   applied during the handshake; on a WolfSSL build that 777   applied during the handshake; on a WolfSSL build that
778   cannot honor it, the handshake fails with 778   cannot honor it, the handshake fails with
779   `std::errc::function_not_supported` (see Backend Support). 779   `std::errc::function_not_supported` (see Backend Support).
780   780  
781   @par Example 781   @par Example
782   @par !example set_verify_callback 782   @par !example set_verify_callback
783   783  
784   @see verify_context 784   @see verify_context
785   @see set_verify_mode 785   @see set_verify_mode
786   */ 786   */
787   template<typename Callback> 787   template<typename Callback>
788   void set_verify_callback(Callback callback); 788   void set_verify_callback(Callback callback);
789   789  
790   /** Set a callback for Server Name Indication (SNI). 790   /** Set a callback for Server Name Indication (SNI).
791   791  
792   For server connections, this callback is invoked during the TLS 792   For server connections, this callback is invoked during the TLS
793   handshake when a client sends an SNI extension. The callback 793   handshake when a client sends an SNI extension. The callback
794   receives the requested hostname and can accept or reject the 794   receives the requested hostname and can accept or reject the
795   connection. 795   connection.
796   796  
797   @tparam Callback A callable with signature 797   @tparam Callback A callable with signature
798   `bool( std::string_view hostname )`. 798   `bool( std::string_view hostname )`.
799   799  
800   @param callback The SNI callback. Return `true` to accept the 800   @param callback The SNI callback. Return `true` to accept the
801   connection or `false` to reject it with an alert. 801   connection or `false` to reject it with an alert.
802   802  
803   @par Example 803   @par Example
804   @par !example set_servername_callback 804   @par !example set_servername_callback
805   805  
806   @note For virtual hosting with different certificates per hostname, 806   @note For virtual hosting with different certificates per hostname,
807   create separate contexts and select the appropriate one before 807   create separate contexts and select the appropriate one before
808   creating the TLS stream. 808   creating the TLS stream.
809   809  
810   @see tls_stream::set_hostname 810   @see tls_stream::set_hostname
811   */ 811   */
812   template<typename Callback> 812   template<typename Callback>
813   void set_servername_callback(Callback callback); 813   void set_servername_callback(Callback callback);
814   814  
815   private: 815   private:
816   void set_servername_callback_impl( 816   void set_servername_callback_impl(
817   std::function<bool(std::string_view)> callback); 817   std::function<bool(std::string_view)> callback);
818   818  
819   void set_password_callback_impl( 819   void set_password_callback_impl(
820   std::function<std::string(std::size_t, tls_password_purpose)> callback); 820   std::function<std::string(std::size_t, tls_password_purpose)> callback);
821   821  
822   void set_verify_callback_impl( 822   void set_verify_callback_impl(
823   std::function<bool(bool, verify_context&)> callback); 823   std::function<bool(bool, verify_context&)> callback);
824   824  
825   public: 825   public:
826   // 826   //
827   // Revocation Checking 827   // Revocation Checking
828   // 828   //
829   829  
830   /** Add a Certificate Revocation List from memory. 830   /** Add a Certificate Revocation List from memory.
831   831  
832   Adds a CRL to the verification store for checking whether 832   Adds a CRL to the verification store for checking whether
833   certificates have been revoked. CRLs are typically fetched 833   certificates have been revoked. CRLs are typically fetched
834   from the URLs in a certificate's CRL Distribution Points 834   from the URLs in a certificate's CRL Distribution Points
835   extension. 835   extension.
836   836  
837   @param crl The CRL data in DER or PEM format. 837   @param crl The CRL data in DER or PEM format.
838   838  
839   @return Success. The CRL is recorded and decoded when the native 839   @return Success. The CRL is recorded and decoded when the native
840   context is first built; a malformed CRL surfaces as a 840   context is first built; a malformed CRL surfaces as a
841   handshake failure. 841   handshake failure.
842   842  
843   @note CRLs are consulted only when a revocation policy is set via 843   @note CRLs are consulted only when a revocation policy is set via
844   @ref set_revocation_policy. On WolfSSL, CRL checking requires a 844   @ref set_revocation_policy. On WolfSSL, CRL checking requires a
845   build with `HAVE_CRL`; without it, supplying a CRL or a 845   build with `HAVE_CRL`; without it, supplying a CRL or a
846   revocation policy fails the handshake with 846   revocation policy fails the handshake with
847   `std::errc::function_not_supported`. 847   `std::errc::function_not_supported`.
848   848  
849   @see add_crl_file 849   @see add_crl_file
850   @see set_revocation_policy 850   @see set_revocation_policy
851   */ 851   */
852   [[nodiscard]] std::error_code add_crl(std::string_view crl); 852   [[nodiscard]] std::error_code add_crl(std::string_view crl);
853   853  
854   /** Add a Certificate Revocation List from a file. 854   /** Add a Certificate Revocation List from a file.
855   855  
856   Adds a CRL to the verification store for checking whether 856   Adds a CRL to the verification store for checking whether
857   certificates have been revoked. 857   certificates have been revoked.
858   858  
859   @param filename Path to a CRL file (DER or PEM format). 859   @param filename Path to a CRL file (DER or PEM format).
860   860  
861   @return Success, or an error if the file could not be read. The 861   @return Success, or an error if the file could not be read. The
862   CRL is decoded when the native context is first built; a 862   CRL is decoded when the native context is first built; a
863   malformed CRL surfaces as a handshake failure. 863   malformed CRL surfaces as a handshake failure.
864   864  
865   @note CRLs are consulted only when a revocation policy is set via 865   @note CRLs are consulted only when a revocation policy is set via
866   @ref set_revocation_policy (WolfSSL requires a `HAVE_CRL` 866   @ref set_revocation_policy (WolfSSL requires a `HAVE_CRL`
867   build). 867   build).
868   868  
869   @par Example 869   @par Example
870   @par !example add_crl_file 870   @par !example add_crl_file
871   871  
872   @see add_crl 872   @see add_crl
873   @see set_revocation_policy 873   @see set_revocation_policy
874   */ 874   */
875   [[nodiscard]] std::error_code add_crl_file(std::string_view filename); 875   [[nodiscard]] std::error_code add_crl_file(std::string_view filename);
876   876  
877   /** Set the certificate revocation checking policy. 877   /** Set the certificate revocation checking policy.
878   878  
879   Controls how certificate revocation status is checked during 879   Controls how certificate revocation status is checked during
880   verification via CRLs. 880   verification via CRLs.
881   881  
882   @param policy The revocation checking policy. 882   @param policy The revocation checking policy.
883   883  
884   @par Example 884   @par Example
885   @par !example set_revocation_policy 885   @par !example set_revocation_policy
886   886  
887   @note Revocation is checked via CRLs supplied with @ref add_crl / 887   @note Revocation is checked via CRLs supplied with @ref add_crl /
888   @ref add_crl_file. `soft_fail` accepts a certificate whose 888   @ref add_crl_file. `soft_fail` accepts a certificate whose
889   status cannot be determined (missing/expired CRL) but rejects 889   status cannot be determined (missing/expired CRL) but rejects
890   one that is actually revoked; `hard_fail` also rejects unknown 890   one that is actually revoked; `hard_fail` also rejects unknown
891   status. OCSP-based revocation is not available (see the TLS 891   status. OCSP-based revocation is not available (see the TLS
892   guide). On WolfSSL a non-disabled policy requires a `HAVE_CRL` 892   guide). On WolfSSL a non-disabled policy requires a `HAVE_CRL`
893   build, else the handshake fails with 893   build, else the handshake fails with
894   `std::errc::function_not_supported`. 894   `std::errc::function_not_supported`.
895   895  
896   @see tls_revocation_policy 896   @see tls_revocation_policy
897   @see add_crl 897   @see add_crl
898   */ 898   */
899   void set_revocation_policy(tls_revocation_policy policy); 899   void set_revocation_policy(tls_revocation_policy policy);
900   900  
901   // 901   //
902   // Password Handling 902   // Password Handling
903   // 903   //
904   904  
905   /** Set the password callback for encrypted keys. 905   /** Set the password callback for encrypted keys.
906   906  
907   Installs a callback that provides passwords for encrypted 907   Installs a callback that provides passwords for encrypted
908   private keys and PKCS#12 files. The callback is invoked when 908   private keys and PKCS#12 files. The callback is invoked when
909   loading encrypted key material. 909   loading encrypted key material.
910   910  
911   @tparam Callback A callable with signature 911   @tparam Callback A callable with signature
912   `std::string( std::size_t max_length, password_purpose purpose )`. 912   `std::string( std::size_t max_length, password_purpose purpose )`.
913   913  
914   @param callback The password callback. It receives the maximum 914   @param callback The password callback. It receives the maximum
915   password length and the purpose (reading or writing), and 915   password length and the purpose (reading or writing), and
916   returns the password string. 916   returns the password string.
917   917  
918   @par Example 918   @par Example
919   @par !example set_password_callback 919   @par !example set_password_callback
920   920  
921   @see tls_password_purpose 921   @see tls_password_purpose
922   */ 922   */
923   template<typename Callback> 923   template<typename Callback>
924   void set_password_callback(Callback callback); 924   void set_password_callback(Callback callback);
925   }; 925   };
926   #ifdef _MSC_VER 926   #ifdef _MSC_VER
927   #pragma warning(pop) 927   #pragma warning(pop)
928   #endif 928   #endif
929   929  
930   template<typename Callback> 930   template<typename Callback>
931   void 931   void
HITCBC 932   1 tls_context::set_servername_callback(Callback callback) 932   1 tls_context::set_servername_callback(Callback callback)
933   { 933   {
HITCBC 934   1 set_servername_callback_impl(std::move(callback)); 934   1 set_servername_callback_impl(std::move(callback));
HITCBC 935   1 } 935   1 }
936   936  
937   template<typename Callback> 937   template<typename Callback>
938   void 938   void
HITCBC 939   4 tls_context::set_password_callback(Callback callback) 939   4 tls_context::set_password_callback(Callback callback)
940   { 940   {
HITCBC 941   4 set_password_callback_impl(std::move(callback)); 941   4 set_password_callback_impl(std::move(callback));
HITCBC 942   4 } 942   4 }
943   943  
944   template<typename Callback> 944   template<typename Callback>
945   void 945   void
HITCBC 946   2 tls_context::set_verify_callback(Callback callback) 946   2 tls_context::set_verify_callback(Callback callback)
947   { 947   {
HITCBC 948   2 set_verify_callback_impl(std::move(callback)); 948   2 set_verify_callback_impl(std::move(callback));
HITCBC 949   2 } 949   2 }
950   950  
951   } // namespace boost::corosio 951   } // namespace boost::corosio
952   952  
953   #endif 953   #endif