Feature: Add membership notifications on interface

Author: leoplo

README.md

@@ -48,16 +48,37 @@ class MulticastGroupNotifier:
     def notify_membership(self, has_members):
         print(has_members)
 
-notifier = MulticastGroupNotifier()
-multicast_group_obj.add_multicast_routing_entry(notifier)
+group_notifier = MulticastGroupNotifier()
+multicast_group_obj.add_multicast_routing_entry(group_notifier)
 
 # when there is a change of multicast interest (for example group ff05::10:11:12
 # gets interested receivers), the object associated to this object is notified
 # through "notify_membership" method with has_members=True
 
 # if you no longer want to monitor the interest of ff05::10:11:12, remove the
 # notifier from the group
-multicast_group_obj.remove_multicast_routing_entry(notifier)
+multicast_group_obj.remove_multicast_routing_entry(group_notifier)
+
+# get notified of interest informations on this interface
+class MulticastRouterNotifier:
+    def notify_done(self, packet):
+        print('%s joined group %s' % (packet.ip_header.ip_src, packet.ip_header.ip_dst))
+
+    def notify_report(self, packet):
+        print('%s leaved group %s' % (packet.ip_header.ip_src, packet.ip_header.ip_dst)) 
+
+    def notify_removal(self):
+        print('the interface is no longer managed')
+
+    def notify_timeout(self, group_ip):
+        print('membership timeout for group ' + group_ip)
+
+router_notifier = MulticastRouterNotifier()
+intf.interface_state.add_to_notify_entry(router_notifier)
+
+# if you no longer want to monitor the interest this interface, remove the
+# notifier from it
+intf.interface_state.remove_to_notify_entry(router_notifier)
 
 intf.remove()  # stop receiving MLD packets
 ```

mld/mld1/GroupState.py

@@ -103,6 +103,7 @@ def group_membership_timeout(self):
         """
         with self.lock:
             self.get_interface_group_state().group_membership_timeout(self)
+        self.router_state.notify_timeout(self.group_ip)
 
     def retransmit_timeout(self):
         """

mld/mld1/RouterState.py

@@ -1,4 +1,5 @@
 import logging
+from threading import Lock
 from threading import Timer
 
 from mld.utils import TYPE_CHECKING
@@ -36,6 +37,10 @@ def __init__(self, interface: 'InterfaceMLD'):
         self.group_state = {}
         self.group_state_lock = RWLockWrite()
 
+        # instances to notify membership timeout and report or done packet reception
+        self.to_notify_list = []
+        self.to_notify_list_lock = Lock()
+
         # send general query
         packet = PacketMLDHeader(type=mld_globals.MULTICAST_LISTENER_QUERY_TYPE,
                                  max_resp_delay=mld_globals.QUERY_RESPONSE_INTERVAL * 1000)
@@ -139,13 +144,15 @@ def receive_report(self, packet: ReceivedPacket):
         """
         mld_group = packet.payload.group_address
         self.get_group_state(mld_group).receive_report()
+        self.notify_report(packet)
 
     def receive_done(self, packet: ReceivedPacket):
         """
         Received MLD Done packet
         """
         mld_group = packet.payload.group_address
         self.get_group_state(mld_group).receive_done()
+        self.notify_done(packet)
 
     def receive_query(self, packet: ReceivedPacket):
         """
@@ -163,8 +170,51 @@ def remove(self):
         """
         Remove this MLD interface
         Clear all state
+        Notify all interested entries that this interface is no longer managed
         """
         for group in self.group_state.values():
             group.remove()
         self.clear_general_query_timer()
         self.clear_other_querier_present_timer()
+        for to_notify in self.to_notify_list:
+            to_notify.notify_removal()
+        del self.to_notify_list[:]
+
+    ###########################################
+    # Notify Membership packets and Membership timeouts
+    ###########################################
+    def notify_done(self, packet: ReceivedPacket):
+        """
+        Notify all entries interested in this router
+        """
+        for to_notify in self.to_notify_list:
+            to_notify.notify_done(packet=packet)
+
+    def notify_report(self, packet: ReceivedPacket):
+        """
+        Notify all entries interested in this router
+        """
+        for to_notify in self.to_notify_list:
+            to_notify.notify_report(packet=packet)
+
+    def notify_timeout(self, group_ip):
+        """
+        Notify all entries interested in this router
+        """
+        for to_notify in self.to_notify_list:
+            to_notify.notify_timeout(group_ip)
+
+    def add_to_notify_entry(self, to_notify_entry):
+        """
+        A new entry monitoring membership informations
+        """
+        with self.to_notify_list_lock:
+            self.to_notify_list.append(to_notify_entry)
+
+    def remove_to_notify_entry(self, to_notify_entry):
+        """
+        A entry is no longer monitoring membership informations
+        Remove this entry from this object
+        """
+        with self.to_notify_list_lock:
+            self.to_notify_list.remove(to_notify_entry)