=pod =head1 NAME SSL_client_version, SSL_get_version, SSL_is_dtls, SSL_version - get the protocol information of a connection =head1 SYNOPSIS #include 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); =head1 DESCRIPTION SSL_client_version() returns the protocol version used by the client when initiating the connection. SSL_get_version() returns the name of the protocol used for the connection. SSL_is_dtls() returns one if the connection is using DTLS, zero if not. SSL_version() returns the protocol version used for the connection. =head1 RETURN VALUES SSL_get_version() returns one of the following strings: =over 4 =item SSLv3 The connection uses the SSLv3 protocol. =item TLSv1 The connection uses the TLSv1.0 protocol. =item TLSv1.1 The connection uses the TLSv1.1 protocol. =item TLSv1.2 The connection uses the TLSv1.2 protocol. =item TLSv1.3 The connection uses the TLSv1.3 protocol. =item unknown This indicates that no version has been set (no connection established). =back SSL_version() and SSL_client_version() return an integer which could include any of the following: =over 4 =item SSL3_VERSION The connection uses the SSLv3 protocol. =item TLS1_VERSION The connection uses the TLSv1.0 protocol. =item TLS1_1_VERSION The connection uses the TLSv1.1 protocol. =item TLS1_2_VERSION The connection uses the TLSv1.2 protocol. =item TLS1_3_VERSION The connection uses the TLSv1.3 protocol. =back =head1 SEE ALSO L =head1 HISTORY SSL_is_dtls() was added in OpenSSL 1.1.0. =head1 COPYRIGHT Copyright 2001-2017 The OpenSSL Project Authors. All Rights Reserved. Licensed under the OpenSSL license (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 L. =cut