NAME

       SSL_set_bio, SSL_set0_rbio, SSL_set0_wbio - connect the SSL object with a BIO

SYNOPSIS

        #include <openssl/ssl.h>

        void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio);
        void SSL_set0_rbio(SSL *s, BIO *rbio);
        void SSL_set0_wbio(SSL *s, BIO *wbio);

DESCRIPTION

       SSL_set0_rbio() connects the BIO rbio for the read operations of the ssl object. The SSL
       engine inherits the behaviour of rbio. If the BIO is nonblocking then the ssl object will
       also have nonblocking behaviour. This function transfers ownership of rbio to ssl. It will
       be automatically freed using BIO_free_all(3) when the ssl is freed. On calling this
       function, any existing rbio that was previously set will also be freed via a call to
       BIO_free_all(3) (this includes the case where the rbio is set to the same value as
       previously).

       SSL_set0_wbio() works in the same as SSL_set0_rbio() except that it connects the BIO wbio
       for the write operations of the ssl object. Note that if the rbio and wbio are the same
       then SSL_set0_rbio() and SSL_set0_wbio() each take ownership of one reference. Therefore,
       it may be necessary to increment the number of references available using BIO_up_ref(3)
       before calling the set0 functions.

       SSL_set_bio() is similar to SSL_set0_rbio() and SSL_set0_wbio() except that it connects
       both the rbio and the wbio at the same time, and transfers the ownership of rbio and wbio
       to ssl according to the following set of rules:

       • If neither the rbio or wbio have changed from their previous values then nothing is
         done.

       • If the rbio and wbio parameters are different and both are different to their previously
         set values then one reference is consumed for the rbio and one reference is consumed for
         the wbio.

       • If the rbio and wbio parameters are the same and the rbio is not the same as the
         previously set value then one reference is consumed.

       • If the rbio and wbio parameters are the same and the rbio is the same as the previously
         set value, then no additional references are consumed.

       • If the rbio and wbio parameters are different and the rbio is the same as the previously
         set value then one reference is consumed for the wbio and no references are consumed for
         the rbio.

       • If the rbio and wbio parameters are different and the wbio is the same as the previously
         set value and the old rbio and wbio values were the same as each other then one
         reference is consumed for the rbio and no references are consumed for the wbio.

       • If the rbio and wbio parameters are different and the wbio is the same as the previously
         set value and the old rbio and wbio values were different to each other, then one
         reference is consumed for the rbio and one reference is consumed for the wbio.

       Because of this complexity, this function should be avoided; use SSL_set0_rbio() and
       SSL_set0_wbio() instead.

RETURN VALUES

       SSL_set_bio(), SSL_set0_rbio() and SSL_set0_wbio() cannot fail.

SEE ALSO

       SSL_get_rbio(3), SSL_connect(3), SSL_accept(3), SSL_shutdown(3), ssl(7), bio(7)

HISTORY

       SSL_set0_rbio() and SSL_set0_wbio() were added in OpenSSL 1.1.0.

COPYRIGHT

       Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the Apache License 2.0 (the "License").  You may not use this file except
       in compliance with the License.  You can obtain a copy in the file LICENSE in the source
       distribution or at <https://www.openssl.org/source/license.html>.