Add ssl version constants (#5662)

* add ssl version constants

* try to fix ci

* try harder to fix ci

* security: if unavailable, set protocol constants to nonexistent version

* make linter happy

* remove dtls constants

* remove superfluous comment

Author: mhils

src/_cffi_src/openssl/ssl.py

@@ -131,6 +131,12 @@
 static const long TLS_ST_BEFORE;
 static const long TLS_ST_OK;
 
+static const long SSL3_VERSION;
+static const long TLS1_VERSION;
+static const long TLS1_1_VERSION;
+static const long TLS1_2_VERSION;
+static const long TLS1_3_VERSION;
+
 typedef ... SSL_METHOD;
 typedef ... SSL_CTX;
 
@@ -677,6 +683,7 @@
 
 #if CRYPTOGRAPHY_OPENSSL_LESS_THAN_111
 static const long Cryptography_HAS_TLSv1_3 = 0;
+static const long TLS1_3_VERSION = 0;
 static const long SSL_OP_NO_TLSv1_3 = 0;
 static const long SSL_VERIFY_POST_HANDSHAKE = 0;
 int (*SSL_CTX_set_ciphersuites)(SSL_CTX *, const char *) = NULL;

src/cryptography/hazmat/bindings/openssl/_conditional.py

@@ -198,6 +198,7 @@ def cryptography_has_openssl_cleanup():
 
 def cryptography_has_tlsv13():
     return [
+        "TLS1_3_VERSION",
         "SSL_OP_NO_TLSv1_3",
         "SSL_VERIFY_POST_HANDSHAKE",
         "SSL_CTX_set_ciphersuites",