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[dragonfly.git] / secure / lib / libcrypto / man / BIO_f_ssl.3
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138.\" ======================================================================
139.\"
140.IX Title "BIO_f_ssl 3"
141.TH BIO_f_ssl 3 "0.9.7a" "2003-02-19" "OpenSSL"
142.UC
143.SH "NAME"
144BIO_f_ssl, BIO_set_ssl, BIO_get_ssl, BIO_set_ssl_mode, BIO_set_ssl_renegotiate_bytes,
145BIO_get_num_renegotiates, BIO_set_ssl_renegotiate_timeout, BIO_new_ssl,
146BIO_new_ssl_connect, BIO_new_buffer_ssl_connect, BIO_ssl_copy_session_id,
147BIO_ssl_shutdown \- \s-1SSL\s0 \s-1BIO\s0
148.SH "SYNOPSIS"
149.IX Header "SYNOPSIS"
150.Vb 2
151\& #include <openssl/bio.h>
152\& #include <openssl/ssl.h>
153.Ve
154.Vb 1
155\& BIO_METHOD *BIO_f_ssl(void);
156.Ve
157.Vb 9
158\& #define BIO_set_ssl(b,ssl,c) BIO_ctrl(b,BIO_C_SET_SSL,c,(char *)ssl)
159\& #define BIO_get_ssl(b,sslp) BIO_ctrl(b,BIO_C_GET_SSL,0,(char *)sslp)
160\& #define BIO_set_ssl_mode(b,client) BIO_ctrl(b,BIO_C_SSL_MODE,client,NULL)
161\& #define BIO_set_ssl_renegotiate_bytes(b,num) \e
162\& BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_BYTES,num,NULL);
163\& #define BIO_set_ssl_renegotiate_timeout(b,seconds) \e
164\& BIO_ctrl(b,BIO_C_SET_SSL_RENEGOTIATE_TIMEOUT,seconds,NULL);
165\& #define BIO_get_num_renegotiates(b) \e
166\& BIO_ctrl(b,BIO_C_SET_SSL_NUM_RENEGOTIATES,0,NULL);
167.Ve
168.Vb 5
169\& BIO *BIO_new_ssl(SSL_CTX *ctx,int client);
170\& BIO *BIO_new_ssl_connect(SSL_CTX *ctx);
171\& BIO *BIO_new_buffer_ssl_connect(SSL_CTX *ctx);
172\& int BIO_ssl_copy_session_id(BIO *to,BIO *from);
173\& void BIO_ssl_shutdown(BIO *bio);
174.Ve
175.Vb 1
176\& #define BIO_do_handshake(b) BIO_ctrl(b,BIO_C_DO_STATE_MACHINE,0,NULL)
177.Ve
178.SH "DESCRIPTION"
179.IX Header "DESCRIPTION"
180\&\fIBIO_f_ssl()\fR returns the \s-1SSL\s0 \s-1BIO\s0 method. This is a filter \s-1BIO\s0 which
181is a wrapper round the OpenSSL \s-1SSL\s0 routines adding a \s-1BIO\s0 \*(L"flavour\*(R" to
182\&\s-1SSL\s0 I/O.
183.PP
184I/O performed on an \s-1SSL\s0 \s-1BIO\s0 communicates using the \s-1SSL\s0 protocol with
185the SSLs read and write BIOs. If an \s-1SSL\s0 connection is not established
186then an attempt is made to establish one on the first I/O call.
187.PP
188If a \s-1BIO\s0 is appended to an \s-1SSL\s0 \s-1BIO\s0 using \fIBIO_push()\fR it is automatically
189used as the \s-1SSL\s0 BIOs read and write BIOs.
190.PP
191Calling \fIBIO_reset()\fR on an \s-1SSL\s0 \s-1BIO\s0 closes down any current \s-1SSL\s0 connection
192by calling \fISSL_shutdown()\fR. \fIBIO_reset()\fR is then sent to the next \s-1BIO\s0 in
193the chain: this will typically disconnect the underlying transport.
194The \s-1SSL\s0 \s-1BIO\s0 is then reset to the initial accept or connect state.
195.PP
196If the close flag is set when an \s-1SSL\s0 \s-1BIO\s0 is freed then the internal
197\&\s-1SSL\s0 structure is also freed using \fISSL_free()\fR.
198.PP
199\&\fIBIO_set_ssl()\fR sets the internal \s-1SSL\s0 pointer of \s-1BIO\s0 \fBb\fR to \fBssl\fR using
200the close flag \fBc\fR.
201.PP
202\&\fIBIO_get_ssl()\fR retrieves the \s-1SSL\s0 pointer of \s-1BIO\s0 \fBb\fR, it can then be
203manipulated using the standard \s-1SSL\s0 library functions.
204.PP
205\&\fIBIO_set_ssl_mode()\fR sets the \s-1SSL\s0 \s-1BIO\s0 mode to \fBclient\fR. If \fBclient\fR
206is 1 client mode is set. If \fBclient\fR is 0 server mode is set.
207.PP
208\&\fIBIO_set_ssl_renegotiate_bytes()\fR sets the renegotiate byte count
209to \fBnum\fR. When set after every \fBnum\fR bytes of I/O (read and write)
210the \s-1SSL\s0 session is automatically renegotiated. \fBnum\fR must be at
211least 512 bytes.
212.PP
213\&\fIBIO_set_ssl_renegotiate_timeout()\fR sets the renegotiate timeout to
214\&\fBseconds\fR. When the renegotiate timeout elapses the session is
215automatically renegotiated.
216.PP
217\&\fIBIO_get_num_renegotiates()\fR returns the total number of session
218renegotiations due to I/O or timeout.
219.PP
220\&\fIBIO_new_ssl()\fR allocates an \s-1SSL\s0 \s-1BIO\s0 using \s-1SSL_CTX\s0 \fBctx\fR and using
221client mode if \fBclient\fR is non zero.
222.PP
223\&\fIBIO_new_ssl_connect()\fR creates a new \s-1BIO\s0 chain consisting of an
224\&\s-1SSL\s0 \s-1BIO\s0 (using \fBctx\fR) followed by a connect \s-1BIO\s0.
225.PP
226\&\fIBIO_new_buffer_ssl_connect()\fR creates a new \s-1BIO\s0 chain consisting
227of a buffering \s-1BIO\s0, an \s-1SSL\s0 \s-1BIO\s0 (using \fBctx\fR) and a connect
228\&\s-1BIO\s0.
229.PP
230\&\fIBIO_ssl_copy_session_id()\fR copies an \s-1SSL\s0 session id between
231\&\s-1BIO\s0 chains \fBfrom\fR and \fBto\fR. It does this by locating the
232\&\s-1SSL\s0 BIOs in each chain and calling \fISSL_copy_session_id()\fR on
233the internal \s-1SSL\s0 pointer.
234.PP
235\&\fIBIO_ssl_shutdown()\fR closes down an \s-1SSL\s0 connection on \s-1BIO\s0
236chain \fBbio\fR. It does this by locating the \s-1SSL\s0 \s-1BIO\s0 in the
237chain and calling \fISSL_shutdown()\fR on its internal \s-1SSL\s0
238pointer.
239.PP
240\&\fIBIO_do_handshake()\fR attempts to complete an \s-1SSL\s0 handshake on the
241supplied \s-1BIO\s0 and establish the \s-1SSL\s0 connection. It returns 1
242if the connection was established successfully. A zero or negative
243value is returned if the connection could not be established, the
244call \fIBIO_should_retry()\fR should be used for non blocking connect BIOs
245to determine if the call should be retried. If an \s-1SSL\s0 connection has
246already been established this call has no effect.
247.SH "NOTES"
248.IX Header "NOTES"
249\&\s-1SSL\s0 BIOs are exceptional in that if the underlying transport
250is non blocking they can still request a retry in exceptional
251circumstances. Specifically this will happen if a session
252renegotiation takes place during a \fIBIO_read()\fR operation, one
253case where this happens is when \s-1SGC\s0 or step up occurs.
254.PP
255In OpenSSL 0.9.6 and later the \s-1SSL\s0 flag \s-1SSL_AUTO_RETRY\s0 can be
256set to disable this behaviour. That is when this flag is set
257an \s-1SSL\s0 \s-1BIO\s0 using a blocking transport will never request a
258retry.
259.PP
260Since unknown \fIBIO_ctrl()\fR operations are sent through filter
261BIOs the servers name and port can be set using \fIBIO_set_host()\fR
262on the \s-1BIO\s0 returned by \fIBIO_new_ssl_connect()\fR without having
263to locate the connect \s-1BIO\s0 first.
264.PP
265Applications do not have to call \fIBIO_do_handshake()\fR but may wish
266to do so to separate the handshake process from other I/O
267processing.
268.SH "RETURN VALUES"
269.IX Header "RETURN VALUES"
270\&\s-1TBA\s0
271.SH "EXAMPLE"
272.IX Header "EXAMPLE"
273This \s-1SSL/TLS\s0 client example, attempts to retrieve a page from an
274\&\s-1SSL/TLS\s0 web server. The I/O routines are identical to those of the
275unencrypted example in BIO_s_connect(3).
276.PP
277.Vb 5
278\& BIO *sbio, *out;
279\& int len;
280\& char tmpbuf[1024];
281\& SSL_CTX *ctx;
282\& SSL *ssl;
283.Ve
284.Vb 3
285\& ERR_load_crypto_strings();
286\& ERR_load_SSL_strings();
287\& OpenSSL_add_all_algorithms();
288.Ve
289.Vb 3
290\& /* We would seed the PRNG here if the platform didn't
291\& * do it automatically
292\& */
293.Ve
294.Vb 1
295\& ctx = SSL_CTX_new(SSLv23_client_method());
296.Ve
297.Vb 4
298\& /* We'd normally set some stuff like the verify paths and
299\& * mode here because as things stand this will connect to
300\& * any server whose certificate is signed by any CA.
301\& */
302.Ve
303.Vb 1
304\& sbio = BIO_new_ssl_connect(ctx);
305.Ve
306.Vb 1
307\& BIO_get_ssl(sbio, &ssl);
308.Ve
309.Vb 4
310\& if(!ssl) {
311\& fprintf(stderr, "Can't locate SSL pointer\en");
312\& /* whatever ... */
313\& }
314.Ve
315.Vb 2
316\& /* Don't want any retries */
317\& SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
318.Ve
319.Vb 1
320\& /* We might want to do other things with ssl here */
321.Ve
322.Vb 1
323\& BIO_set_conn_hostname(sbio, "localhost:https");
324.Ve
325.Vb 6
326\& out = BIO_new_fp(stdout, BIO_NOCLOSE);
327\& if(BIO_do_connect(sbio) <= 0) {
328\& fprintf(stderr, "Error connecting to server\en");
329\& ERR_print_errors_fp(stderr);
330\& /* whatever ... */
331\& }
332.Ve
333.Vb 5
334\& if(BIO_do_handshake(sbio) <= 0) {
335\& fprintf(stderr, "Error establishing SSL connection\en");
336\& ERR_print_errors_fp(stderr);
337\& /* whatever ... */
338\& }
339.Ve
340.Vb 1
341\& /* Could examine ssl here to get connection info */
342.Ve
343.Vb 8
344\& BIO_puts(sbio, "GET / HTTP/1.0\en\en");
345\& for(;;) {
346\& len = BIO_read(sbio, tmpbuf, 1024);
347\& if(len <= 0) break;
348\& BIO_write(out, tmpbuf, len);
349\& }
350\& BIO_free_all(sbio);
351\& BIO_free(out);
352.Ve
353Here is a simple server example. It makes use of a buffering
354\&\s-1BIO\s0 to allow lines to be read from the \s-1SSL\s0 \s-1BIO\s0 using BIO_gets.
355It creates a pseudo web page containing the actual request from
356a client and also echoes the request to standard output.
357.PP
358.Vb 5
359\& BIO *sbio, *bbio, *acpt, *out;
360\& int len;
361\& char tmpbuf[1024];
362\& SSL_CTX *ctx;
363\& SSL *ssl;
364.Ve
365.Vb 3
366\& ERR_load_crypto_strings();
367\& ERR_load_SSL_strings();
368\& OpenSSL_add_all_algorithms();
369.Ve
370.Vb 1
371\& /* Might seed PRNG here */
372.Ve
373.Vb 1
374\& ctx = SSL_CTX_new(SSLv23_server_method());
375.Ve
376.Vb 3
377\& if (!SSL_CTX_use_certificate_file(ctx,"server.pem",SSL_FILETYPE_PEM)
378\& || !SSL_CTX_use_PrivateKey_file(ctx,"server.pem",SSL_FILETYPE_PEM)
379\& || !SSL_CTX_check_private_key(ctx)) {
380.Ve
381.Vb 4
382\& fprintf(stderr, "Error setting up SSL_CTX\en");
383\& ERR_print_errors_fp(stderr);
384\& return 0;
385\& }
386.Ve
387.Vb 3
388\& /* Might do other things here like setting verify locations and
389\& * DH and/or RSA temporary key callbacks
390\& */
391.Ve
392.Vb 2
393\& /* New SSL BIO setup as server */
394\& sbio=BIO_new_ssl(ctx,0);
395.Ve
396.Vb 1
397\& BIO_get_ssl(sbio, &ssl);
398.Ve
399.Vb 4
400\& if(!ssl) {
401\& fprintf(stderr, "Can't locate SSL pointer\en");
402\& /* whatever ... */
403\& }
404.Ve
405.Vb 2
406\& /* Don't want any retries */
407\& SSL_set_mode(ssl, SSL_MODE_AUTO_RETRY);
408.Ve
409.Vb 1
410\& /* Create the buffering BIO */
411.Ve
412.Vb 1
413\& bbio = BIO_new(BIO_f_buffer());
414.Ve
415.Vb 2
416\& /* Add to chain */
417\& sbio = BIO_push(bbio, sbio);
418.Ve
419.Vb 1
420\& acpt=BIO_new_accept("4433");
421.Ve
422.Vb 5
423\& /* By doing this when a new connection is established
424\& * we automatically have sbio inserted into it. The
425\& * BIO chain is now 'swallowed' by the accept BIO and
426\& * will be freed when the accept BIO is freed.
427\& */
428.Ve
429.Vb 1
430\& BIO_set_accept_bios(acpt,sbio);
431.Ve
432.Vb 1
433\& out = BIO_new_fp(stdout, BIO_NOCLOSE);
434.Ve
435.Vb 6
436\& /* Setup accept BIO */
437\& if(BIO_do_accept(acpt) <= 0) {
438\& fprintf(stderr, "Error setting up accept BIO\en");
439\& ERR_print_errors_fp(stderr);
440\& return 0;
441\& }
442.Ve
443.Vb 6
444\& /* Now wait for incoming connection */
445\& if(BIO_do_accept(acpt) <= 0) {
446\& fprintf(stderr, "Error in connection\en");
447\& ERR_print_errors_fp(stderr);
448\& return 0;
449\& }
450.Ve
451.Vb 3
452\& /* We only want one connection so remove and free
453\& * accept BIO
454\& */
455.Ve
456.Vb 1
457\& sbio = BIO_pop(acpt);
458.Ve
459.Vb 1
460\& BIO_free_all(acpt);
461.Ve
462.Vb 5
463\& if(BIO_do_handshake(sbio) <= 0) {
464\& fprintf(stderr, "Error in SSL handshake\en");
465\& ERR_print_errors_fp(stderr);
466\& return 0;
467\& }
468.Ve
469.Vb 3
470\& BIO_puts(sbio, "HTTP/1.0 200 OK\er\enContent-type: text/html\er\en\er\en");
471\& BIO_puts(sbio, "<pre>\er\enConnection Established\er\enRequest headers:\er\en");
472\& BIO_puts(sbio, "--------------------------------------------------\er\en");
473.Ve
474.Vb 8
475\& for(;;) {
476\& len = BIO_gets(sbio, tmpbuf, 1024);
477\& if(len <= 0) break;
478\& BIO_write(sbio, tmpbuf, len);
479\& BIO_write(out, tmpbuf, len);
480\& /* Look for blank line signifying end of headers*/
481\& if((tmpbuf[0] == '\er') || (tmpbuf[0] == '\en')) break;
482\& }
483.Ve
484.Vb 2
485\& BIO_puts(sbio, "--------------------------------------------------\er\en");
486\& BIO_puts(sbio, "</pre>\er\en");
487.Ve
488.Vb 2
489\& /* Since there is a buffering BIO present we had better flush it */
490\& BIO_flush(sbio);
491.Ve
492.Vb 1
493\& BIO_free_all(sbio);
494.Ve
495.SH "SEE ALSO"
496.IX Header "SEE ALSO"
497\&\s-1TBA\s0