New monitoring, add one IP address per interface and add rules to don't contact them directly

Signed-off-by: Yohann D'ANELLO <ynerant@crans.org>

re6st/tunnel.py

@@ -70,6 +70,7 @@ class Connection(object):
         self.address_list = address_list
         self.iface = iface
         self._prefix = prefix
+        self._monitoring_address = None
 
     def __iter__(self):
         if not hasattr(self, '_remote_ip_set'):
@@ -99,6 +100,22 @@ class Connection(object):
         self._retry += 1
 
     def connected(self, serial):
+        # Generate random IP address in the prefix
+        # FIXME Run DAD
+        # TODO Check if there are enough IP addresses. If not, we have to find a rule.
+        prefix = self.tunnel_manager.ctl.network + self.tunnel_manager._prefix
+        suffix = bin(random.randint(2, 2 ** (128 - len(prefix))))[2:]
+        self._monitoring_address = utils.ipFromBin(prefix, suffix)
+        # Add IP address on Re6stnet interface
+        subprocess.check_call(('ip', '-6', 'address', 'add', self._monitoring_address, 'dev', self.iface))
+        subprocess.check_call(('ip', '-6', 'route', 'del', self._monitoring_address))
+        # Add IP rule to indicate to search main route first instead of local route
+        # FIXME Get main interface instead of hardcoding 'lo'
+        subprocess.check_call(('ip', '-6', 'rule', 'add', 'from', utils.ipFromBin(prefix, '1'),
+                               'to', self._monitoring_address, 'iif', 'lo', 'priority', '0'))
+        subprocess.check_call(('ip', '-6', 'rule', 'del', 'from', 'all', 'lookup', 'local', 'priority', '0'))
+        subprocess.check_call(('ip', '-6', 'rule', 'add', 'from', 'all', 'lookup', 'local', 'priority', '1'))
+
         cache = self.tunnel_manager.cache
         if serial in cache.crl:
             self.tunnel_manager._kill(self._prefix)
@@ -112,6 +129,11 @@ class Connection(object):
             cache.connecting(self._prefix, 0)
 
     def close(self):
+        if self._monitoring_address:
+            # Remove address and reset IP rule
+            subprocess.check_call(('ip', '-6', 'address', 'del', self._monitoring_address, 'dev', self.iface))
+            subprocess.check_call(('ip', '-6', 'rule', 'del', 'to', self._monitoring_address, 'priority', '0'))
+
         try:
             self.process.stop()
         except AttributeError:
@@ -666,6 +688,30 @@ class BaseTunnelManager(object):
                     '\7%s (%s)' % (msg, os.uname()[2]))
                 break
 
+    def updateMonitoringLinks(self):
+        """
+        Refresh routes that are used for link monitoring.
+        """
+        # Cleanup old routes
+        for connection in self._connection_dict.values():
+            if connection._monitoring_address:
+                subprocess.check_call(('ip', '-6', 'route', 'del', connection._monitoring_address,
+                                       'dev', connection.iface))
+
+        # Get nexthop for each prefix, and draw a route for monitoring addresses
+        for prefix in self.ctl.neighbours.keys():
+            if prefix is None or prefix not in self._connection_dict:
+                continue
+            neighbour = self.ctl.neighbours[prefix][0]
+            nexthop = neighbour.address
+            nexthop = utils.ipFromBin("".join(bin(ord(c))[2:].zfill(8) for c in nexthop))
+
+            connection = self._connection_dict[prefix]
+            address = connection._monitoring_address
+
+            # Add route in kernel
+            subprocess.check_call(('ip', '-6', 'route', 'add', address, 'via', nexthop, 'dev', connection.iface))
+
     def _updateCountry(self, address):
         def update():
             for a in address:
@@ -740,6 +786,7 @@ class TunnelManager(BaseTunnelManager):
                 '--dev', iface, '--dev-type', 'tap')
         logging.debug('%r', args)
         subprocess.check_call(args)
+
         return iface
 
     def delInterfaces(self):
@@ -776,6 +823,7 @@ class TunnelManager(BaseTunnelManager):
         else:
             self._next_refresh = time.time() + 5
         self.checkRoutingCache()
+        self.updateMonitoringLinks()
 
     def babel_dump(self):
         t = time.time()