1SSL_GET_VERSION(3)                  OpenSSL                 SSL_GET_VERSION(3)
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NAME

6       SSL_client_version, SSL_get_version, SSL_is_dtls, SSL_version - get the
7       protocol information of a connection
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SYNOPSIS

10        #include <openssl/ssl.h>
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12        int SSL_client_version(const SSL *s);
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14        const char *SSL_get_version(const SSL *ssl);
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16        int SSL_is_dtls(const SSL *ssl);
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18        int SSL_version(const SSL *s);
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DESCRIPTION

21       SSL_client_version() returns the numeric protocol version advertised by
22       the client in the legacy_version field of the ClientHello when
23       initiating the connection. Note that, for TLS, this value will never
24       indicate a version greater than TLSv1.2 even if TLSv1.3 is subsequently
25       negotiated. SSL_get_version() returns the name of the protocol used for
26       the connection. SSL_version() returns the numeric protocol version used
27       for the connection. They should only be called after the initial
28       handshake has been completed. Prior to that the results returned from
29       these functions may be unreliable.
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31       SSL_is_dtls() returns one if the connection is using DTLS, zero if not.
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RETURN VALUES

34       SSL_get_version() returns one of the following strings:
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36       SSLv3
37           The connection uses the SSLv3 protocol.
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39       TLSv1
40           The connection uses the TLSv1.0 protocol.
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42       TLSv1.1
43           The connection uses the TLSv1.1 protocol.
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45       TLSv1.2
46           The connection uses the TLSv1.2 protocol.
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48       TLSv1.3
49           The connection uses the TLSv1.3 protocol.
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51       unknown
52           This indicates an unknown protocol version.
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54       SSL_version() and SSL_client_version() return an integer which could
55       include any of the following:
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57       SSL3_VERSION
58           The connection uses the SSLv3 protocol.
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60       TLS1_VERSION
61           The connection uses the TLSv1.0 protocol.
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63       TLS1_1_VERSION
64           The connection uses the TLSv1.1 protocol.
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66       TLS1_2_VERSION
67           The connection uses the TLSv1.2 protocol.
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69       TLS1_3_VERSION
70           The connection uses the TLSv1.3 protocol (never returned for
71           SSL_client_version()).
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SEE ALSO

74       ssl(7)
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HISTORY

77       The SSL_is_dtls() function was added in OpenSSL 1.1.0.
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80       Copyright 2001-2018 The OpenSSL Project Authors. All Rights Reserved.
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82       Licensed under the OpenSSL license (the "License").  You may not use
83       this file except in compliance with the License.  You can obtain a copy
84       in the file LICENSE in the source distribution or at
85       <https://www.openssl.org/source/license.html>.
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891.1.1g                            2020-04-23                SSL_GET_VERSION(3)
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