xref: /netbsd-src/crypto/external/bsd/openssl/lib/libcrypto/man/SSL_get_version.3 (revision 7d9ffdb3e9da593a05c5e2169f72fc7bada08bc9)
$NetBSD: SSL_get_version.3,v 1.25 2024/09/08 13:08:35 christos Exp $

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Title "SSL_get_version 3"
SSL_get_version 3 2024-09-03 3.0.15 OpenSSL
For nroff, turn off justification. Always turn off hyphenation; it makes
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NAME
SSL_client_version, SSL_get_version, SSL_is_dtls, SSL_version - get the protocol information of a connection
SYNOPSIS
Header "SYNOPSIS" .Vb 1 #include <openssl/ssl.h> \& int SSL_client_version(const SSL *s); \& const char *SSL_get_version(const SSL *ssl); \& int SSL_is_dtls(const SSL *ssl); \& int SSL_version(const SSL *s); .Ve
DESCRIPTION
Header "DESCRIPTION" \fBSSL_client_version() returns the numeric protocol version advertised by the client in the legacy_version field of the ClientHello when initiating the connection. Note that, for TLS, this value will never indicate a version greater than TLSv1.2 even if TLSv1.3 is subsequently negotiated. SSL_get_version() returns the name of the protocol used for the connection. SSL_version() returns the numeric protocol version used for the connection. They should only be called after the initial handshake has been completed. Prior to that the results returned from these functions may be unreliable.

\fBSSL_is_dtls() returns one if the connection is using DTLS, zero if not.

"RETURN VALUES"
Header "RETURN VALUES" \fBSSL_get_version() returns one of the following strings:
SSLv3 4
Item "SSLv3" The connection uses the SSLv3 protocol.
TLSv1 4
Item "TLSv1" The connection uses the TLSv1.0 protocol.
TLSv1.1 4
Item "TLSv1.1" The connection uses the TLSv1.1 protocol.
TLSv1.2 4
Item "TLSv1.2" The connection uses the TLSv1.2 protocol.
TLSv1.3 4
Item "TLSv1.3" The connection uses the TLSv1.3 protocol.
unknown 4
Item "unknown" This indicates an unknown protocol version.

\fBSSL_version() and SSL_client_version() return an integer which could include any of the following:

SSL3_VERSION 4
Item "SSL3_VERSION" The connection uses the SSLv3 protocol.
TLS1_VERSION 4
Item "TLS1_VERSION" The connection uses the TLSv1.0 protocol.
TLS1_1_VERSION 4
Item "TLS1_1_VERSION" The connection uses the TLSv1.1 protocol.
TLS1_2_VERSION 4
Item "TLS1_2_VERSION" The connection uses the TLSv1.2 protocol.
TLS1_3_VERSION 4
Item "TLS1_3_VERSION" The connection uses the TLSv1.3 protocol (never returned for \fBSSL_client_version()).
"SEE ALSO"
Header "SEE ALSO" \fBssl\|(7)
HISTORY
Header "HISTORY" The SSL_is_dtls() function was added in OpenSSL 1.1.0.
COPYRIGHT
Header "COPYRIGHT" Copyright 2001-2018 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>.