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.\" $OpenBSD: SSL_get_session.3,v 1.7 2018/03/27 17:35:50 schwarze Exp $
.\" OpenSSL b97fdb57 Nov 11 09:33:09 2016 +0100
.\"
.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>.
.\" Copyright (c) 2000, 2001, 2005, 2013, 2016 The OpenSSL Project.
.\" All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\"
.\" 1. Redistributions of source code must retain the above copyright
.\" notice, this list of conditions and the following disclaimer.
.\"
.\" 2. Redistributions in binary form must reproduce the above copyright
.\" notice, this list of conditions and the following disclaimer in
.\" the documentation and/or other materials provided with the
.\" distribution.
.\"
.\" 3. All advertising materials mentioning features or use of this
.\" software must display the following acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)"
.\"
.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to
.\" endorse or promote products derived from this software without
.\" prior written permission. For written permission, please contact
.\" openssl-core@openssl.org.
.\"
.\" 5. Products derived from this software may not be called "OpenSSL"
.\" nor may "OpenSSL" appear in their names without prior written
.\" permission of the OpenSSL Project.
.\"
.\" 6. Redistributions of any form whatsoever must retain the following
.\" acknowledgment:
.\" "This product includes software developed by the OpenSSL Project
.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)"
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY
.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR
.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
.\" OF THE POSSIBILITY OF SUCH DAMAGE.
.\"
.Dd $Mdocdate: March 27 2018 $
.Dt SSL_GET_SESSION 3
.Os
.Sh NAME
.Nm SSL_get_session ,
.Nm SSL_get0_session ,
.Nm SSL_get1_session
.Nd retrieve TLS/SSL session data
.Sh SYNOPSIS
.In openssl/ssl.h
.Ft SSL_SESSION *
.Fn SSL_get_session "const SSL *ssl"
.Ft SSL_SESSION *
.Fn SSL_get0_session "const SSL *ssl"
.Ft SSL_SESSION *
.Fn SSL_get1_session "SSL *ssl"
.Sh DESCRIPTION
.Fn SSL_get_session
returns a pointer to the
.Vt SSL_SESSION
actually used in
.Fa ssl .
The reference count of the
.Vt SSL_SESSION
is not incremented, so that the pointer can become invalid by other operations.
.Pp
.Fn SSL_get0_session
is the same as
.Fn SSL_get_session .
.Pp
.Fn SSL_get1_session
is the same as
.Fn SSL_get_session ,
but the reference count of the
.Vt SSL_SESSION
is incremented by one.
.Pp
The
.Fa ssl
session contains all information required to re-establish the connection
without a new handshake.
.Pp
.Fn SSL_get0_session
returns a pointer to the actual session.
As the reference counter is not incremented,
the pointer is only valid while the connection is in use.
If
.Xr SSL_clear 3
or
.Xr SSL_free 3
is called, the session may be removed completely (if considered bad),
and the pointer obtained will become invalid.
Even if the session is valid,
it can be removed at any time due to timeout during
.Xr SSL_CTX_flush_sessions 3 .
.Pp
If the data is to be kept,
.Fn SSL_get1_session
will increment the reference count, so that the session will not be implicitly
removed by other operations but stays in memory.
In order to remove the session
.Xr SSL_SESSION_free 3
must be explicitly called once to decrement the reference count again.
.Pp
.Vt SSL_SESSION
objects keep internal link information about the session cache list when being
inserted into one
.Vt SSL_CTX
object's session cache.
One
.Vt SSL_SESSION
object, regardless of its reference count, must therefore only be used with one
.Vt SSL_CTX
object (and the
.Vt SSL
objects created from this
.Vt SSL_CTX
object).
.Sh RETURN VALUES
The following return values can occur:
.Bl -tag -width Ds
.It Dv NULL
There is no session available in
.Fa ssl .
.It Pointer to an Vt SSL_SESSION
The return value points to the data of an
.Vt SSL
session.
.El
.Sh SEE ALSO
.Xr ssl 3 ,
.Xr SSL_clear 3 ,
.Xr SSL_free 3 ,
.Xr SSL_SESSION_free 3 ,
.Xr SSL_SESSION_get0_peer 3 ,
.Xr SSL_SESSION_get_compress_id 3 ,
.Xr SSL_SESSION_get_id 3 ,
.Xr SSL_SESSION_get_protocol_version 3 ,
.Xr SSL_SESSION_get_time 3 ,
.Xr SSL_SESSION_new 3 ,
.Xr SSL_SESSION_print 3 ,
.Xr SSL_set_session 3
.Sh HISTORY
.Fn SSL_get_session
first appeared in SSLeay 0.5.2 and has been available since
.Ox 2.4 .
.Pp
.Fn SSL_get0_session
and
.Fn SSL_get1_session
first appeared in OpenSSL 0.9.5 and have been available since
.Ox 2.7 .
|
