SSL_get_version3ssl

Usage

 #include <openssl/ssl.h>
 int SSL_client_version(const SSL *s);
 const char *SSL_get_version(const SSL *ssl);
 int SSL_is_dtls(const SSL *ssl);
 int SSL_is_tls(const SSL *ssl);
 int SSL_is_quic(const SSL *ssl);
 int SSL_version(const SSL *s);

Overview

For SSL, TLS and DTLS protocols SSL_client_version() returns the numeric protocol version advertised by the client in the legacy_version field of the ClientHello when initiating the connection. Note that, for TLS, this value will never indicate a version greater than TLSv1.2 even if TLSv1.3 is subsequently negotiated. For QUIC connections it returns OSSL_QUIC1_VERSION.

SSL_get_version() returns the name of the protocol used for the connection. SSL_version() returns the numeric 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 1 if the connection is using DTLS or 0 if not.

SSL_is_tls() returns 1 if the connection is using SSL/TLS or 0 if not.

SSL_is_quic() returns 1 if the connection is using QUIC or 0 if not.

Return values

SSL_get_version() returns one of the following strings:

SSL_version() and SSL_client_version() return an integer which could include any of the following:

SSL3_VERSION

The connection uses the SSLv3 protocol.

TLS1_VERSION

The connection uses the TLSv1.0 protocol.

TLS1_1_VERSION

The connection uses the TLSv1.1 protocol.

TLS1_2_VERSION

The connection uses the TLSv1.2 protocol.

TLS1_3_VERSION

The connection uses the TLSv1.3 protocol (never returned for SSL_client_version()).

DTLS1_BAD_VER

The connection uses an obsolete pre-standardisation DTLS protocol

DTLS1_VERSION

The connection uses the DTLSv1 protocol

DTLS1_2_VERSION

The connection uses the DTLSv1.2 protocol

OSSL_QUIC1_VERSION

The connection uses the QUICv1 protocol.