diff options
Diffstat (limited to 'src/lib/libcrypto/man/BIO_s_bio.3')
-rw-r--r-- | src/lib/libcrypto/man/BIO_s_bio.3 | 416 |
1 files changed, 0 insertions, 416 deletions
diff --git a/src/lib/libcrypto/man/BIO_s_bio.3 b/src/lib/libcrypto/man/BIO_s_bio.3 deleted file mode 100644 index efda019df3..0000000000 --- a/src/lib/libcrypto/man/BIO_s_bio.3 +++ /dev/null | |||
@@ -1,416 +0,0 @@ | |||
1 | .\" $OpenBSD: BIO_s_bio.3,v 1.20 2024/05/19 07:12:50 jsg Exp $ | ||
2 | .\" full merge up to: OpenSSL 99d63d46 Oct 26 13:56:48 2016 -0400 | ||
3 | .\" | ||
4 | .\" This file was written by | ||
5 | .\" Lutz Jaenicke <Lutz.Jaenicke@aet.TU-Cottbus.DE>, | ||
6 | .\" Dr. Stephen Henson <steve@openssl.org>, | ||
7 | .\" Bodo Moeller <bodo@openssl.org>, | ||
8 | .\" and Richard Levitte <levitte@openssl.org>. | ||
9 | .\" Copyright (c) 2000, 2002, 2015, 2016 The OpenSSL Project. | ||
10 | .\" All rights reserved. | ||
11 | .\" | ||
12 | .\" Redistribution and use in source and binary forms, with or without | ||
13 | .\" modification, are permitted provided that the following conditions | ||
14 | .\" are met: | ||
15 | .\" | ||
16 | .\" 1. Redistributions of source code must retain the above copyright | ||
17 | .\" notice, this list of conditions and the following disclaimer. | ||
18 | .\" | ||
19 | .\" 2. Redistributions in binary form must reproduce the above copyright | ||
20 | .\" notice, this list of conditions and the following disclaimer in | ||
21 | .\" the documentation and/or other materials provided with the | ||
22 | .\" distribution. | ||
23 | .\" | ||
24 | .\" 3. All advertising materials mentioning features or use of this | ||
25 | .\" software must display the following acknowledgment: | ||
26 | .\" "This product includes software developed by the OpenSSL Project | ||
27 | .\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" | ||
28 | .\" | ||
29 | .\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to | ||
30 | .\" endorse or promote products derived from this software without | ||
31 | .\" prior written permission. For written permission, please contact | ||
32 | .\" openssl-core@openssl.org. | ||
33 | .\" | ||
34 | .\" 5. Products derived from this software may not be called "OpenSSL" | ||
35 | .\" nor may "OpenSSL" appear in their names without prior written | ||
36 | .\" permission of the OpenSSL Project. | ||
37 | .\" | ||
38 | .\" 6. Redistributions of any form whatsoever must retain the following | ||
39 | .\" acknowledgment: | ||
40 | .\" "This product includes software developed by the OpenSSL Project | ||
41 | .\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" | ||
42 | .\" | ||
43 | .\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY | ||
44 | .\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE | ||
45 | .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR | ||
46 | .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR | ||
47 | .\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, | ||
48 | .\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT | ||
49 | .\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; | ||
50 | .\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) | ||
51 | .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, | ||
52 | .\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) | ||
53 | .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED | ||
54 | .\" OF THE POSSIBILITY OF SUCH DAMAGE. | ||
55 | .\" | ||
56 | .Dd $Mdocdate: May 19 2024 $ | ||
57 | .Dt BIO_S_BIO 3 | ||
58 | .Os | ||
59 | .Sh NAME | ||
60 | .Nm BIO_s_bio , | ||
61 | .Nm BIO_make_bio_pair , | ||
62 | .Nm BIO_destroy_bio_pair , | ||
63 | .Nm BIO_shutdown_wr , | ||
64 | .Nm BIO_set_write_buf_size , | ||
65 | .Nm BIO_get_write_buf_size , | ||
66 | .Nm BIO_new_bio_pair , | ||
67 | .Nm BIO_get_write_guarantee , | ||
68 | .Nm BIO_ctrl_get_write_guarantee , | ||
69 | .Nm BIO_get_read_request , | ||
70 | .Nm BIO_ctrl_get_read_request , | ||
71 | .Nm BIO_ctrl_reset_read_request | ||
72 | .Nd BIO pair BIO | ||
73 | .Sh SYNOPSIS | ||
74 | .In openssl/bio.h | ||
75 | .Ft const BIO_METHOD * | ||
76 | .Fo BIO_s_bio | ||
77 | .Fa void | ||
78 | .Fc | ||
79 | .Ft int | ||
80 | .Fo BIO_make_bio_pair | ||
81 | .Fa "BIO *b1" | ||
82 | .Fa "BIO *b2" | ||
83 | .Fc | ||
84 | .Ft int | ||
85 | .Fo BIO_destroy_bio_pair | ||
86 | .Fa "BIO *b" | ||
87 | .Fc | ||
88 | .Ft int | ||
89 | .Fo BIO_shutdown_wr | ||
90 | .Fa "BIO *b" | ||
91 | .Fc | ||
92 | .Ft int | ||
93 | .Fo BIO_set_write_buf_size | ||
94 | .Fa "BIO *b" | ||
95 | .Fa "long size" | ||
96 | .Fc | ||
97 | .Ft size_t | ||
98 | .Fo BIO_get_write_buf_size | ||
99 | .Fa "BIO *b" | ||
100 | .Fa "long size" | ||
101 | .Fc | ||
102 | .Ft int | ||
103 | .Fo BIO_new_bio_pair | ||
104 | .Fa "BIO **bio1" | ||
105 | .Fa "size_t writebuf1" | ||
106 | .Fa "BIO **bio2" | ||
107 | .Fa "size_t writebuf2" | ||
108 | .Fc | ||
109 | .Ft int | ||
110 | .Fo BIO_get_write_guarantee | ||
111 | .Fa "BIO *b" | ||
112 | .Fc | ||
113 | .Ft size_t | ||
114 | .Fo BIO_ctrl_get_write_guarantee | ||
115 | .Fa "BIO *b" | ||
116 | .Fc | ||
117 | .Ft int | ||
118 | .Fo BIO_get_read_request | ||
119 | .Fa "BIO *b" | ||
120 | .Fc | ||
121 | .Ft size_t | ||
122 | .Fo BIO_ctrl_get_read_request | ||
123 | .Fa "BIO *b" | ||
124 | .Fc | ||
125 | .Ft int | ||
126 | .Fo BIO_ctrl_reset_read_request | ||
127 | .Fa "BIO *b" | ||
128 | .Fc | ||
129 | .Sh DESCRIPTION | ||
130 | .Fn BIO_s_bio | ||
131 | returns the method for a BIO pair. | ||
132 | A BIO pair is a pair of source/sink BIOs where data written to either | ||
133 | half of the pair is buffered and can be read from the other half. | ||
134 | Both halves must usually be handled by the same application thread | ||
135 | since no locking is done on the internal data structures. | ||
136 | .Pp | ||
137 | Since BIO chains typically end in a source/sink BIO, | ||
138 | it is possible to make this one half of a BIO pair and | ||
139 | have all the data processed by the chain under application control. | ||
140 | .Pp | ||
141 | One typical use of BIO pairs is | ||
142 | to place TLS/SSL I/O under application control. | ||
143 | This can be used when the application wishes to use a non-standard | ||
144 | transport for TLS/SSL or the normal socket routines are inappropriate. | ||
145 | .Pp | ||
146 | Calls to | ||
147 | .Xr BIO_read 3 | ||
148 | will read data from the buffer or request a retry if no data is available. | ||
149 | .Pp | ||
150 | Calls to | ||
151 | .Xr BIO_write 3 | ||
152 | will place data in the buffer or request a retry if the buffer is full. | ||
153 | .Pp | ||
154 | The standard calls | ||
155 | .Xr BIO_ctrl_pending 3 | ||
156 | and | ||
157 | .Xr BIO_ctrl_wpending 3 | ||
158 | can be used to determine the amount of pending data | ||
159 | in the read or write buffer. | ||
160 | .Pp | ||
161 | .Xr BIO_reset 3 | ||
162 | clears any data in the write buffer. | ||
163 | .Pp | ||
164 | .Fn BIO_make_bio_pair | ||
165 | joins two separate BIOs into a connected pair. | ||
166 | .Pp | ||
167 | .Fn BIO_destroy_pair | ||
168 | destroys the association between two connected BIOs. | ||
169 | Freeing up any half of the pair will automatically destroy the association. | ||
170 | .Pp | ||
171 | .Fn BIO_shutdown_wr | ||
172 | is used to close down a BIO | ||
173 | .Fa b . | ||
174 | After this call no further writes on BIO | ||
175 | .Fa b | ||
176 | are allowed; they will return an error. | ||
177 | Reads on the other half of the pair will return any pending data | ||
178 | or EOF when all pending data has been read. | ||
179 | .Pp | ||
180 | .Fn BIO_set_write_buf_size | ||
181 | sets the write buffer size of BIO | ||
182 | .Fa b | ||
183 | to | ||
184 | .Fa size . | ||
185 | If the size is not initialized, a default value is used. | ||
186 | This is currently 17K, sufficient for a maximum size TLS record. | ||
187 | When a chain containing a BIO pair is copied with | ||
188 | .Xr BIO_dup_chain 3 , | ||
189 | the write buffer size is automatically copied | ||
190 | from the original BIO object to the new one. | ||
191 | .Pp | ||
192 | .Fn BIO_get_write_buf_size | ||
193 | returns the size of the write buffer. | ||
194 | .Pp | ||
195 | .Fn BIO_new_bio_pair | ||
196 | combines the calls to | ||
197 | .Xr BIO_new 3 , | ||
198 | .Fn BIO_make_bio_pair | ||
199 | and | ||
200 | .Fn BIO_set_write_buf_size | ||
201 | to create a connected pair of BIOs | ||
202 | .Fa bio1 | ||
203 | and | ||
204 | .Fa bio2 | ||
205 | with write buffer sizes | ||
206 | .Fa writebuf1 | ||
207 | and | ||
208 | .Fa writebuf2 . | ||
209 | If either size is zero, then the default size is used. | ||
210 | .Fn BIO_new_bio_pair | ||
211 | does not check whether | ||
212 | .Fa bio1 | ||
213 | or | ||
214 | .Fa bio2 | ||
215 | point to some other BIO; the values are overwritten and | ||
216 | .Xr BIO_free 3 | ||
217 | is not called. | ||
218 | .Pp | ||
219 | .Fn BIO_get_write_guarantee | ||
220 | and | ||
221 | .Fn BIO_ctrl_get_write_guarantee | ||
222 | return the maximum length of data | ||
223 | that can be currently written to the BIO. | ||
224 | Writes larger than this value will return a value from | ||
225 | .Xr BIO_write 3 | ||
226 | less than the amount requested or if the buffer is full request a retry. | ||
227 | .Fn BIO_ctrl_get_write_guarantee | ||
228 | is a function whereas | ||
229 | .Fn BIO_get_write_guarantee | ||
230 | is a macro. | ||
231 | .Pp | ||
232 | .Fn BIO_get_read_request | ||
233 | and | ||
234 | .Fn BIO_ctrl_get_read_request | ||
235 | return the amount of data requested, or the buffer size if it is less, | ||
236 | if the last read attempt at the other half of the BIO pair failed | ||
237 | due to an empty buffer. | ||
238 | This can be used to determine how much data should be | ||
239 | written to the BIO so the next read will succeed: | ||
240 | this is most useful in TLS/SSL applications where the amount of | ||
241 | data read is usually meaningful rather than just a buffer size. | ||
242 | After a successful read this call will return zero. | ||
243 | It also will return zero once new data has been written | ||
244 | satisfying the read request or part of it. | ||
245 | Note that | ||
246 | .Fn BIO_get_read_request | ||
247 | never returns an amount larger than that returned by | ||
248 | .Fn BIO_get_write_guarantee . | ||
249 | .Pp | ||
250 | .Fn BIO_ctrl_reset_read_request | ||
251 | can also be used to reset the value returned by | ||
252 | .Fn BIO_get_read_request | ||
253 | to zero. | ||
254 | .Pp | ||
255 | Both halves of a BIO pair should be freed. | ||
256 | Even if one half is implicitly freed due to a | ||
257 | .Xr BIO_free_all 3 | ||
258 | or | ||
259 | .Xr SSL_free 3 | ||
260 | call, the other half still needs to be freed. | ||
261 | .Pp | ||
262 | When used in bidirectional applications (such as TLS/SSL), | ||
263 | care should be taken to flush any data in the write buffer. | ||
264 | This can be done by calling | ||
265 | .Xr BIO_pending 3 | ||
266 | on the other half of the pair and, if any data is pending, | ||
267 | reading it and sending it to the underlying transport. | ||
268 | This must be done before any normal processing (such as calling | ||
269 | .Xr select 2 ) | ||
270 | due to a request and | ||
271 | .Xr BIO_should_read 3 | ||
272 | being true. | ||
273 | .Pp | ||
274 | To see why this is important, | ||
275 | consider a case where a request is sent using | ||
276 | .Xr BIO_write 3 | ||
277 | and a response read with | ||
278 | .Xr BIO_read 3 , | ||
279 | this can occur during a TLS/SSL handshake for example. | ||
280 | .Xr BIO_write 3 | ||
281 | will succeed and place data in the write buffer. | ||
282 | .Xr BIO_read 3 | ||
283 | will initially fail and | ||
284 | .Xr BIO_should_read 3 | ||
285 | will be true. | ||
286 | If the application then waits for data to become available | ||
287 | on the underlying transport before flushing the write buffer, | ||
288 | it will never succeed because the request was never sent. | ||
289 | .Pp | ||
290 | .Xr BIO_eof 3 | ||
291 | is true if no data is in the peer BIO and the peer BIO has been shutdown. | ||
292 | .Pp | ||
293 | .Xr BIO_ctrl 3 | ||
294 | .Fa cmd | ||
295 | arguments correspond to macros as follows: | ||
296 | .Bl -column BIO_C_GET_WRITE_GUARANTEE BIO_ctrl_reset_read_request() -offset 3n | ||
297 | .It Fa cmd No constant Ta corresponding macro | ||
298 | .It Dv BIO_C_DESTROY_BIO_PAIR Ta Fn BIO_destroy_bio_pair | ||
299 | .It Dv BIO_C_GET_READ_REQUEST Ta Fn BIO_get_read_request | ||
300 | .It Dv BIO_C_GET_WRITE_BUF_SIZE Ta Fn BIO_get_write_buf_size | ||
301 | .It Dv BIO_C_GET_WRITE_GUARANTEE Ta Fn BIO_get_write_guarantee | ||
302 | .It Dv BIO_C_MAKE_BIO_PAIR Ta Fn BIO_make_bio_pair | ||
303 | .It Dv BIO_C_RESET_READ_REQUEST Ta Fn BIO_ctrl_reset_read_request | ||
304 | .It Dv BIO_C_SET_WRITE_BUF_SIZE Ta Fn BIO_set_write_buf_size | ||
305 | .It Dv BIO_C_SHUTDOWN_WR Ta Fn BIO_shutdown_wr | ||
306 | .It Dv BIO_CTRL_EOF Ta Xr BIO_eof 3 | ||
307 | .It Dv BIO_CTRL_GET_CLOSE Ta Xr BIO_get_close 3 | ||
308 | .It Dv BIO_CTRL_PENDING Ta Xr BIO_pending 3 | ||
309 | .It Dv BIO_CTRL_RESET Ta Xr BIO_reset 3 | ||
310 | .It Dv BIO_CTRL_SET_CLOSE Ta Xr BIO_set_close 3 | ||
311 | .It Dv BIO_CTRL_WPENDING Ta Xr BIO_wpending 3 | ||
312 | .El | ||
313 | .Sh RETURN VALUES | ||
314 | .Fn BIO_new_bio_pair | ||
315 | returns 1 on success, with the new BIOs available in | ||
316 | .Fa bio1 | ||
317 | and | ||
318 | .Fa bio2 , | ||
319 | or 0 on failure, with NULL pointers stored into the locations for | ||
320 | .Fa bio1 | ||
321 | and | ||
322 | .Fa bio2 . | ||
323 | Check the error stack for more information. | ||
324 | .Pp | ||
325 | When called on a BIO pair BIO object, | ||
326 | .Xr BIO_method_type 3 | ||
327 | returns the constant | ||
328 | .Dv BIO_TYPE_BIO | ||
329 | and | ||
330 | .Xr BIO_method_name 3 | ||
331 | returns a pointer to the static string | ||
332 | .Qq BIO pair . | ||
333 | .\" XXX More return values need to be added here. | ||
334 | .Sh EXAMPLES | ||
335 | The BIO pair can be used to have full control | ||
336 | over the network access of an application. | ||
337 | The application can call | ||
338 | .Xr select 2 | ||
339 | on the socket as required without having to go through the SSL interface. | ||
340 | .Bd -literal -offset 2n | ||
341 | BIO *internal_bio, *network_bio; | ||
342 | \&... | ||
343 | BIO_new_bio_pair(&internal_bio, 0, &network_bio, 0); | ||
344 | SSL_set_bio(ssl, internal_bio, internal_bio); | ||
345 | SSL_operations(); /* e.g. SSL_read() and SSL_write() */ | ||
346 | \&... | ||
347 | |||
348 | application | TLS-engine | ||
349 | | | | ||
350 | +----------> SSL_operations() | ||
351 | | /\e || | ||
352 | | || \e/ | ||
353 | | BIO-pair (internal_bio) | ||
354 | | BIO-pair (network_bio) | ||
355 | | || /\e | ||
356 | | \e/ || | ||
357 | +-----------< BIO_operations() | ||
358 | | | | ||
359 | socket | | ||
360 | |||
361 | \&... | ||
362 | SSL_free(ssl); /* implicitly frees internal_bio */ | ||
363 | BIO_free(network_bio); | ||
364 | \&... | ||
365 | .Ed | ||
366 | .Pp | ||
367 | As the BIO pair will only buffer the data and never directly access | ||
368 | the connection, it behaves non-blocking and will return as soon as | ||
369 | the write buffer is full or the read buffer is drained. | ||
370 | Then the application has to flush the write buffer | ||
371 | and/or fill the read buffer. | ||
372 | .Pp | ||
373 | Use | ||
374 | .Xr BIO_ctrl_pending 3 | ||
375 | to find out whether data is buffered in the BIO | ||
376 | and must be transferred to the network. | ||
377 | Use | ||
378 | .Fn BIO_ctrl_get_read_request | ||
379 | to find out how many bytes must be written into the buffer before the | ||
380 | SSL operations can successfully be continued. | ||
381 | .Sh SEE ALSO | ||
382 | .Xr BIO_new 3 , | ||
383 | .Xr BIO_read 3 , | ||
384 | .Xr BIO_should_retry 3 , | ||
385 | .Xr ssl 3 , | ||
386 | .Xr SSL_set_bio 3 | ||
387 | .Sh HISTORY | ||
388 | .Fn BIO_s_bio , | ||
389 | .Fn BIO_make_bio_pair , | ||
390 | .Fn BIO_destroy_bio_pair , | ||
391 | .Fn BIO_set_write_buf_size , | ||
392 | .Fn BIO_get_write_buf_size , | ||
393 | .Fn BIO_new_bio_pair , | ||
394 | .Fn BIO_get_write_guarantee , | ||
395 | .Fn BIO_ctrl_get_write_guarantee , | ||
396 | .Fn BIO_get_read_request , | ||
397 | and | ||
398 | .Fn BIO_ctrl_reset_read_request | ||
399 | first appeared in OpenSSL 0.9.4 and have been available since | ||
400 | .Ox 2.6 . | ||
401 | .Pp | ||
402 | .Fn BIO_ctrl_reset_read_request | ||
403 | first appeared in OpenSSL 0.9.5 and has been available since | ||
404 | .Ox 2.7 . | ||
405 | .Pp | ||
406 | .Fn BIO_shutdown_wr | ||
407 | first appeared in OpenSSL 0.9.6 and has been available since | ||
408 | .Ox 2.9 . | ||
409 | .Sh CAVEATS | ||
410 | As the data is buffered, SSL operations may return with an | ||
411 | .Dv ERROR_SSL_WANT_READ | ||
412 | condition, but there is still data in the write buffer. | ||
413 | An application must not rely on the error value of the SSL operation | ||
414 | but must assure that the write buffer is always flushed first. | ||
415 | Otherwise a deadlock may occur as the peer might be waiting | ||
416 | for the data before being able to continue. | ||