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SSL_GET_VERSION(3) Library Functions Manual SSL_GET_VERSION(3)

SSL_get_version, SSL_is_dtls, SSL_versionget the protocol information of a connection

#include <openssl/ssl.h>

const char *
SSL_get_version(const SSL *ssl);

SSL_is_dtls(const SSL *ssl);

SSL_version(const SSL *ssl);

() returns the name of the protocol used for the connection ssl.

() returns 1 if the connection is using DTLS, 0 if not.

() returns an integer constant representing that protocol.

These functions only return reliable results after the initial handshake has been completed.

The following strings or integers can be returned by SSL_get_version() and SSL_version():

The connection uses the TLSv1.0 protocol.
"TLSv1.1" or TLS1_1_VERSION
The connection uses the TLSv1.1 protocol.
"TLSv1.2" or TLS1_2_VERSION
The connection uses the TLSv1.2 protocol.
"TLSv1.3" or TLS1_3_VERSION
The connection uses the TLSv1.3 protocol.
The connection uses the Datagram Transport Layer Security 1.0 protocol.
The connection uses the Datagram Transport Layer Security 1.2 protocol.
This indicates an unknown protocol version; it cannot currently happen with LibreSSL.

SSL_is_dtls() returns 1 if the connection uses DTLS, 0 if not.


SSL_get_version() and SSL_version() first appeared in SSLeay 0.8.0 and have been available since OpenBSD 2.4.

SSL_is_dtls() first appeared in OpenSSL 1.1.0 and has been available since OpenBSD 6.9.

April 15, 2021 OpenBSD-current