xref: /freebsd/crypto/openssl/doc/man3/SSL_set_bio.pod (revision ba3c1f5972d7b90feb6e6da47905ff2757e0fe57)
1=pod
2
3=head1 NAME
4
5SSL_set_bio, SSL_set0_rbio, SSL_set0_wbio - connect the SSL object with a BIO
6
7=head1 SYNOPSIS
8
9 #include <openssl/ssl.h>
10
11 void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio);
12 void SSL_set0_rbio(SSL *s, BIO *rbio);
13 void SSL_set0_wbio(SSL *s, BIO *wbio);
14
15=head1 DESCRIPTION
16
17SSL_set0_rbio() connects the BIO B<rbio> for the read operations of the B<ssl>
18object. The SSL engine inherits the behaviour of B<rbio>. If the BIO is
19nonblocking then the B<ssl> object will also have nonblocking behaviour. This
20function transfers ownership of B<rbio> to B<ssl>. It will be automatically
21freed using L<BIO_free_all(3)> when the B<ssl> is freed. On calling this
22function, any existing B<rbio> that was previously set will also be freed via a
23call to L<BIO_free_all(3)> (this includes the case where the B<rbio> is set to
24the same value as previously).
25
26SSL_set0_wbio() works in the same as SSL_set0_rbio() except that it connects
27the BIO B<wbio> for the write operations of the B<ssl> object. Note that if the
28rbio and wbio are the same then SSL_set0_rbio() and SSL_set0_wbio() each take
29ownership of one reference. Therefore, it may be necessary to increment the
30number of references available using L<BIO_up_ref(3)> before calling the set0
31functions.
32
33SSL_set_bio() is similar to SSL_set0_rbio() and SSL_set0_wbio() except
34that it connects both the B<rbio> and the B<wbio> at the same time, and
35transfers the ownership of B<rbio> and B<wbio> to B<ssl> according to
36the following set of rules:
37
38=over 2
39
40=item *
41
42If neither the B<rbio> or B<wbio> have changed from their previous values
43then nothing is done.
44
45=item *
46
47If the B<rbio> and B<wbio> parameters are different and both are different
48to their
49previously set values then one reference is consumed for the rbio and one
50reference is consumed for the wbio.
51
52=item *
53
54If the B<rbio> and B<wbio> parameters are the same and the B<rbio> is not
55the same as the previously set value then one reference is consumed.
56
57=item *
58
59If the B<rbio> and B<wbio> parameters are the same and the B<rbio> is the
60same as the previously set value, then no additional references are consumed.
61
62=item *
63
64If the B<rbio> and B<wbio> parameters are different and the B<rbio> is the
65same as the
66previously set value then one reference is consumed for the B<wbio> and no
67references are consumed for the B<rbio>.
68
69=item *
70
71If the B<rbio> and B<wbio> parameters are different and the B<wbio> is the
72same as the previously set value and the old B<rbio> and B<wbio> values
73were the same as each other then one reference is consumed for the B<rbio>
74and no references are consumed for the B<wbio>.
75
76=item *
77
78If the B<rbio> and B<wbio> parameters are different and the B<wbio>
79is the same as the
80previously set value and the old B<rbio> and B<wbio> values were different
81to each other, then one reference is consumed for the B<rbio> and one
82reference is consumed for the B<wbio>.
83
84=back
85
86Because of this complexity, this function should be avoided;
87use SSL_set0_rbio() and SSL_set0_wbio() instead.
88
89=head1 RETURN VALUES
90
91SSL_set_bio(), SSL_set0_rbio() and SSL_set0_wbio() cannot fail.
92
93=head1 SEE ALSO
94
95L<SSL_get_rbio(3)>,
96L<SSL_connect(3)>, L<SSL_accept(3)>,
97L<SSL_shutdown(3)>, L<ssl(7)>, L<bio(7)>
98
99=head1 HISTORY
100
101SSL_set0_rbio() and SSL_set0_wbio() were added in OpenSSL 1.1.0.
102
103=head1 COPYRIGHT
104
105Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.
106
107Licensed under the Apache License 2.0 (the "License").  You may not use
108this file except in compliance with the License.  You can obtain a copy
109in the file LICENSE in the source distribution or at
110L<https://www.openssl.org/source/license.html>.
111
112=cut
113