From e040a42e44b40f09ce485f66c9198456a3f8a457 Mon Sep 17 00:00:00 2001 From: Matt Caswell <matt@openssl.org> Date: Fri, 22 Jul 2016 11:55:10 +0100 Subject: [PATCH] Update the SSL_set_bio()/SSL_set0_rbio()/SSL_set0_wbio() docs Update the documentation for the newly renamed and modified SSL_set0_rbio() and SSL_set0_wbio() functions. State that they should be preferred over SSL_set_bio(). Attempt to document the ownership rules for SSL_set_bio(). Reviewed-by: Rich Salz <rsalz@openssl.org> --- doc/ssl/SSL_set_bio.pod | 82 ++++++++++++++++++++++++++++++++++------- 1 file changed, 68 insertions(+), 14 deletions(-) diff --git a/doc/ssl/SSL_set_bio.pod b/doc/ssl/SSL_set_bio.pod index 204c89e3fc..e8e55f4648 100644 --- a/doc/ssl/SSL_set_bio.pod +++ b/doc/ssl/SSL_set_bio.pod @@ -2,31 +2,85 @@ =head1 NAME -SSL_set_bio, SSL_set_rbio, SSL_set_wbio - connect the SSL object with a BIO +SSL_set_bio, SSL_set0_rbio, SSL_set0_wbio - connect the SSL object with a BIO =head1 SYNOPSIS #include <openssl/ssl.h> void SSL_set_bio(SSL *ssl, BIO *rbio, BIO *wbio); - void SSL_set_rbio(SSL *s, BIO *rbio); - void SSL_set_wbio(SSL *s, BIO *wbio); + void SSL_set0_rbio(SSL *s, BIO *rbio); + void SSL_set0_wbio(SSL *s, BIO *wbio); =head1 DESCRIPTION -SSL_set_bio() connects the BIOs B<rbio> and B<wbio> for the read and write -operations of the TLS/SSL (encrypted) side of B<ssl>. +SSL_set0_rbio() connects the BIO B<rbio> for the read operations of the B<ssl> +object. The SSL engine inherits the behaviour of B<rbio>. If the BIO is +non-blocking then the B<ssl> object will also have non-blocking behaviour. This +function transfers ownership of B<rbio> to B<ssl>. It will be automatically +freed using L<BIO_free_all(3)> when the B<ssl> is freed. On calling this +function, any existing B<rbio> that was previously set will also be freed via a +call to L<BIO_free_all(3)> (this includes the case where the B<rbio> is set to +the same value as previously). -The SSL engine inherits the behaviour of B<rbio> and B<wbio>, respectively. -If a BIO is non-blocking, the B<ssl> will also have non-blocking behaviour. +SSL_set0_wbio() works in the same as SSL_set0_rbio() except that it connects +the BIO B<wbio> for the write operations of the B<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 L<BIO_up_ref(3)> before calling the set0 +functions. -If there was already a BIO connected to B<ssl>, BIO_free() will be called -(for both the reading and writing side, if different). +SSL_set_bio() does a similar job as SSL_set0_rbio() and SSL_set0_wbio() except +that it connects both the B<rbio> and the B<wbio> at the same time. This +function transfers the ownership of B<rbio> and B<wbio> to B<ssl> except that +the rules for this are much more complex. For this reason this function is +considered a legacy function and SSL_set0_rbio() and SSL_set0_wbio() should be +used in preference. The ownership rules are as follows: -SSL_set_rbio() does the same job as SSL_set_bio() except that it enables you -to only connect the read bio, without touching the write bio. Similarly -SSL_set_wbio() enables you to connect the write bio without touching the read -bio. +=over 4 + +=item + +If neither the rbio or wbio have changed from their previous values then nothing +is done. + +=item + +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. + +=item + +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. + +=item + +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. + +=item + +If the rbio and wbio parameters are different and the rbio is the same as the +previously set value then one reference is consumbed for the wbio and no +references are consumed for the rbio. + +=item + +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. + +=item + +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. + +=back =head1 RETURN VALUES @@ -40,7 +94,7 @@ L<SSL_shutdown(3)>, L<ssl(3)>, L<bio(3)> =head1 HISTORY -SSL_set_rbio() and SSL_set_wbio() were added in OpenSSL 1.1.0. +SSL_set0_rbio() and SSL_set0_wbio() were added in OpenSSL 1.1.0. =head1 COPYRIGHT -- 2.25.1