Do not fail on unexpected 'route_up' notifications from OpenVPN clients

This fixes the following error:

  TypeError: unsupported operand type(s) for -: 'NoneType' and 'int'
  Traceback (most recent call last):
    File "/usr/sbin/re6stnet", line 438, in main
      tunnel_manager.handleTunnelEvent(read_pipe.readline())
    File "/usr/lib/python2.7/dist-packages/re6st/tunnel.py", line 389, in handleTunnelEvent
      m(*args)
    File "/usr/lib/python2.7/dist-packages/re6st/tunnel.py", line 412, in _ovpn_route_up
      self._connection_dict[prefix].connected()
    File "/usr/lib/python2.7/dist-packages/re6st/tunnel.py", line 76, in connected
      i = self._retry - 1

What happened is probably that a route_up notification was received just before
killing/recreating the connection for the same node, and then process twice
the same OpenVPN notification: in this case, the first was for a previous
connection and should have been ignored.

re6st/ovpn-client

 #!/usr/bin/python -S
 import os, sys
 
-if os.environ['script_type'] == 'up':
+script_type = os.environ['script_type']
+if script_type == 'up':
     # OpenVPN unsets PATH before calling hooks
     # which is equivalent to set /bin:/usr/bin
     os.environ['PATH'] = '/bin:/sbin:/usr/bin:/usr/sbin'
@@ -9,4 +10,6 @@ if os.environ['script_type'] == 'up':
               'mtu', os.environ['tun_mtu'])
 
 # Write into pipe external ip address received
-os.write(int(sys.argv[1]), '%(script_type)s %(common_name)s %(OPENVPN_external_ip)s\n' % os.environ)
+import time
+os.write(int(sys.argv[1]), "%s %s %s %s\n" % (script_type,
+  os.environ['common_name'], time.time(), os.environ['OPENVPN_external_ip']))

re6st/tunnel.py

@@ -40,6 +40,7 @@ class MultiGatewayManager(dict):
 class Connection(object):
 
     _retry = routes = 0
+    time = float('inf')
 
     def __init__(self, tunnel_manager, address_list, iface, prefix):
         self.tunnel_manager = tunnel_manager
@@ -60,6 +61,7 @@ class Connection(object):
 
     def open(self):
         tm = self.tunnel_manager
+        self.time = time.time()
         self.process = plib.client(
             self.iface, (self.address_list[self._retry],), tm.encrypt,
             '--tls-remote', '%u/%u' % (int(self._prefix, 2), len(self._prefix)),
@@ -406,12 +408,17 @@ class TunnelManager(object):
         if self._gateway_manager is not None:
             self._gateway_manager.remove(trusted_ip)
 
-    def _ovpn_route_up(self, common_name, ip):
+    def _ovpn_route_up(self, common_name, time, ip):
         prefix = utils.binFromSubnet(common_name)
-        try:
-            self._connection_dict[prefix].connected()
-        except KeyError:
-            pass
+        c = self._connection_dict.get(prefix)
+        if c and c.time < float(time):
+            try:
+                c.connected()
+            except (KeyError, TypeError), e:
+                logging.error("%s (route_up %s)", e, common_name)
+        else:
+            logging.info("ignore route_up notification for %s %r",
+                         common_name, tuple(self._connection_dict))
         if self._ip_changed:
             family, address = self._ip_changed(ip)
             if address: