dtls_ver_ordinal
#define DTLS_VERSION_GT(v1, v2) (dtls_ver_ordinal(v1) < dtls_ver_ordinal(v2))
#define DTLS_VERSION_GE(v1, v2) (dtls_ver_ordinal(v1) <= dtls_ver_ordinal(v2))
#define DTLS_VERSION_LT(v1, v2) (dtls_ver_ordinal(v1) > dtls_ver_ordinal(v2))
#define DTLS_VERSION_LE(v1, v2) (dtls_ver_ordinal(v1) >= dtls_ver_ordinal(v2))