1=pod 2 3=head1 NAME 4 5SSL_client_version, SSL_get_version, SSL_is_dtls, SSL_is_tls, SSL_is_quic, 6SSL_version - get the protocol information of a connection 7 8=head1 SYNOPSIS 9 10 #include <openssl/ssl.h> 11 12 int SSL_client_version(const SSL *s); 13 14 const char *SSL_get_version(const SSL *ssl); 15 16 int SSL_is_dtls(const SSL *ssl); 17 int SSL_is_tls(const SSL *ssl); 18 int SSL_is_quic(const SSL *ssl); 19 20 int SSL_version(const SSL *s); 21 22=head1 DESCRIPTION 23 24For SSL, TLS and DTLS protocols SSL_client_version() returns the numeric 25protocol version advertised by the client in the legacy_version field of the 26ClientHello when initiating the connection. Note that, for TLS, this value 27will never indicate a version greater than TLSv1.2 even if TLSv1.3 is 28subsequently negotiated. For QUIC connections it returns OSSL_QUIC1_VERSION. 29 30SSL_get_version() returns the name of the protocol used for the connection. 31SSL_version() returns the numeric protocol version used for the connection. 32They should only be called after the initial handshake has been completed. 33Prior to that the results returned from these functions may be unreliable. 34 35SSL_is_dtls() returns 1 if the connection is using DTLS or 0 if not. 36 37SSL_is_tls() returns 1 if the connection is using SSL/TLS or 0 if not. 38 39SSL_is_quic() returns 1 if the connection is using QUIC or 0 if not. 40 41=head1 RETURN VALUES 42 43 44SSL_get_version() returns one of the following strings: 45 46=over 4 47 48=item SSLv3 49 50The connection uses the SSLv3 protocol. 51 52=item TLSv1 53 54The connection uses the TLSv1.0 protocol. 55 56=item TLSv1.1 57 58The connection uses the TLSv1.1 protocol. 59 60=item TLSv1.2 61 62The connection uses the TLSv1.2 protocol. 63 64=item TLSv1.3 65 66The connection uses the TLSv1.3 protocol. 67 68=item DTLSv0.9 69 70The connection uses an obsolete pre-standardisation DTLS protocol 71 72=item DTLSv1 73 74The connection uses the DTLSv1 protocol 75 76=item DTLSv1.2 77 78The connection uses the DTLSv1.2 protocol 79 80=item QUICv1 81 82The connection uses the QUICv1 protocol. 83 84=item unknown 85 86This indicates an unknown protocol version. 87 88=back 89 90SSL_version() and SSL_client_version() return an integer which could include any 91of the following: 92 93=over 4 94 95=item SSL3_VERSION 96 97The connection uses the SSLv3 protocol. 98 99=item TLS1_VERSION 100 101The connection uses the TLSv1.0 protocol. 102 103=item TLS1_1_VERSION 104 105The connection uses the TLSv1.1 protocol. 106 107=item TLS1_2_VERSION 108 109The connection uses the TLSv1.2 protocol. 110 111=item TLS1_3_VERSION 112 113The connection uses the TLSv1.3 protocol (never returned for 114SSL_client_version()). 115 116=item DTLS1_BAD_VER 117 118The connection uses an obsolete pre-standardisation DTLS protocol 119 120=item DTLS1_VERSION 121 122The connection uses the DTLSv1 protocol 123 124=item DTLS1_2_VERSION 125 126The connection uses the DTLSv1.2 protocol 127 128=item OSSL_QUIC1_VERSION 129 130The connection uses the QUICv1 protocol. 131 132=back 133 134=head1 SEE ALSO 135 136L<ssl(7)> 137 138=head1 HISTORY 139 140The SSL_is_dtls() function was added in OpenSSL 1.1.0. The SSL_is_tls() and 141SSL_is_quic() functions were added in OpenSSL 3.2. 142 143=head1 COPYRIGHT 144 145Copyright 2001-2023 The OpenSSL Project Authors. All Rights Reserved. 146 147Licensed under the Apache License 2.0 (the "License"). You may not use 148this file except in compliance with the License. You can obtain a copy 149in the file LICENSE in the source distribution or at 150L<https://www.openssl.org/source/license.html>. 151 152=cut 153
