=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_version() returns the 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. SSL_is_dtls() returns one if the connection is using DTLS, zero if not. =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 an unknown protocol version. =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 2001-2018 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