ssl_tls_to_dtls_version
if ((max_proto = ssl_tls_to_dtls_version(max_version)) == 0)
if ((max_version = ssl_tls_to_dtls_version(max_version)) == 0)
if ((max_version = ssl_tls_to_dtls_version(max_version)) == 0)
shared_version = ssl_tls_to_dtls_version(shared_version);
if ((min_proto = ssl_tls_to_dtls_version(min_version)) == 0)