Add configuration item for versions

oregano/configuration.py

@@ -1,6 +1,3 @@
-from gnutls.crypto import X509Certificate, X509CRL, X509PrivateKey
-from gnutls.connection import X509Credentials
-
 # Default settings for what is undeclared.
 default_settings = {
     "address": "0.0.0.0",
@@ -47,6 +44,14 @@
         # base64 encode of our ntor onion key, the private part
         "ntor_onion_secret_key": "MAnGt1ArmYV1/W8AwfVlyxIQXV+NIMRttytfD2+J1F4=",
 
+        # the link protocol versions we are offering to the upstream server
+        # see https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n571 for available values
+        "versions_offered_to_server": (3, 4, 5),
+
+        # the link protocol versions we are offering to our clients
+        # see https://gitweb.torproject.org/torspec.git/tree/tor-spec.txt#n571 for available values
+        "versions_offered_to_client": (3, 4, 5),
+
         # the SNI to be sent to the upstream server
         # for example
         # "server_name_indicator": "example.org",

oregano/onion.py

@@ -93,15 +93,17 @@ def cell_is_var_length(command):
 
 class ORConnImpl:
 
-    our_versions = frozenset((3, 4, 5))
+    supported_versions = frozenset((3, 4, 5))
 
-    def __init__(self, conn):
+    def __init__(self, conn, our_versions):
         self.conn = conn
         self.buf = ''
 
         self.circid_len = 0
         self.version = 0
 
+        self.our_versions = self.supported_versions & our_versions
+
     def read_from_conn(self):
         data = self.conn.recv(4096)
 

oregano/proxy.py

@@ -212,7 +212,7 @@ def send_to_remote(self, data):
             self.remote.sendall(data)
 
     def or_handshake_with_client(self):
-        self.client_or_conn = ORConnImpl(self.session)
+        self.client_or_conn = ORConnImpl(self.session, frozenset(self.server.config.versions_offered_to_client))
 
         self.client_or_conn.process_versions_cell(self.client_or_conn.get_one_cell())
 
@@ -227,7 +227,7 @@ def or_handshake_with_client(self):
         self.client_or_conn.process_netinfo_cell(self.client_or_conn.get_one_cell())
 
     def or_handshake_with_server(self):
-        self.server_or_conn = ORConnImpl(self.remote)
+        self.server_or_conn = ORConnImpl(self.remote, frozenset(self.server.config.versions_offered_to_server))
 
         self.send_to_remote(self.server_or_conn.versions_cell())