1.\" $OpenBSD: SSL_get_version.3,v 1.9 2021/04/15 16:13:22 tb Exp $ 2.\" full merge up to: OpenSSL e417070c Jun 8 11:37:06 2016 -0400 3.\" selective merge up to: OpenSSL df75c2bf Dec 9 01:02:36 2018 +0100 4.\" 5.\" This file was written by Lutz Jaenicke <jaenicke@openssl.org>. 6.\" Copyright (c) 2001, 2005, 2014 The OpenSSL Project. All rights reserved. 7.\" 8.\" Redistribution and use in source and binary forms, with or without 9.\" modification, are permitted provided that the following conditions 10.\" are met: 11.\" 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 15.\" 2. Redistributions in binary form must reproduce the above copyright 16.\" notice, this list of conditions and the following disclaimer in 17.\" the documentation and/or other materials provided with the 18.\" distribution. 19.\" 20.\" 3. All advertising materials mentioning features or use of this 21.\" software must display the following acknowledgment: 22.\" "This product includes software developed by the OpenSSL Project 23.\" for use in the OpenSSL Toolkit. (http://www.openssl.org/)" 24.\" 25.\" 4. The names "OpenSSL Toolkit" and "OpenSSL Project" must not be used to 26.\" endorse or promote products derived from this software without 27.\" prior written permission. For written permission, please contact 28.\" openssl-core@openssl.org. 29.\" 30.\" 5. Products derived from this software may not be called "OpenSSL" 31.\" nor may "OpenSSL" appear in their names without prior written 32.\" permission of the OpenSSL Project. 33.\" 34.\" 6. Redistributions of any form whatsoever must retain the following 35.\" acknowledgment: 36.\" "This product includes software developed by the OpenSSL Project 37.\" for use in the OpenSSL Toolkit (http://www.openssl.org/)" 38.\" 39.\" THIS SOFTWARE IS PROVIDED BY THE OpenSSL PROJECT ``AS IS'' AND ANY 40.\" EXPRESSED OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 41.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 42.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE OpenSSL PROJECT OR 43.\" ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 44.\" SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 45.\" NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 46.\" LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 47.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, 48.\" STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 49.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED 50.\" OF THE POSSIBILITY OF SUCH DAMAGE. 51.\" 52.Dd $Mdocdate: April 15 2021 $ 53.Dt SSL_GET_VERSION 3 54.Os 55.Sh NAME 56.Nm SSL_get_version , 57.Nm SSL_is_dtls , 58.Nm SSL_version 59.\" The following are intentionally undocumented because 60.\" - the longer term plan is to remove them 61.\" - nothing appears to be using them in the wild 62.\" - and they have the wrong namespace prefix 63.\" Nm TLS1_get_version 64.\" Nm TLS1_get_client_version 65.Nd get the protocol information of a connection 66.Sh SYNOPSIS 67.In openssl/ssl.h 68.Ft const char * 69.Fn SSL_get_version "const SSL *ssl" 70.Ft int 71.Fn SSL_is_dtls "const SSL *ssl" 72.Ft int 73.Fn SSL_version "const SSL *ssl" 74.Sh DESCRIPTION 75.Fn SSL_get_version 76returns the name of the protocol used for the connection 77.Fa ssl . 78.Pp 79.Fn SSL_is_dtls 80returns 1 if the connection is using DTLS, 0 if not. 81.Pp 82.Fn SSL_version 83returns an integer constant representing that protocol. 84.Pp 85These functions only return reliable results 86after the initial handshake has been completed. 87.Sh RETURN VALUES 88The following strings or integers can be returned by 89.Fn SSL_get_version 90and 91.Fn SSL_version : 92.Bl -tag -width Ds 93.It Qo TLSv1 Qc No or Dv TLS1_VERSION 94The connection uses the TLSv1.0 protocol. 95.It Qo TLSv1.1 Qc No or Dv TLS1_1_VERSION 96The connection uses the TLSv1.1 protocol. 97.It Qo TLSv1.2 Qc No or Dv TLS1_2_VERSION 98The connection uses the TLSv1.2 protocol. 99.It Qo TLSv1.3 Qc No or Dv TLS1_3_VERSION 100The connection uses the TLSv1.3 protocol. 101.It Qo DTLSv1 Qc No or Dv DTLS1_VERSION 102The connection uses the Datagram Transport Layer Security 1.0 protocol. 103.It Qo DTLSv1.2 Qc No or Dv DTLS1_2_VERSION 104The connection uses the Datagram Transport Layer Security 1.2 protocol. 105.It Qq unknown 106This indicates an unknown protocol version; 107it cannot currently happen with LibreSSL. 108.El 109.Pp 110.Fn SSL_is_dtls 111returns 1 if the connection uses DTLS, 0 if not. 112.Sh SEE ALSO 113.Xr ssl 3 114.Sh HISTORY 115.Fn SSL_get_version 116and 117.Fn SSL_version 118first appeared in SSLeay 0.8.0 and have been available since 119.Ox 2.4 . 120.Pp 121.Fn SSL_is_dtls 122first appeared in OpenSSL 1.1.0 and has been available since 123.Ox 6.9 . 124