[bbr] (Un)Subscribe AllDomainBBRs multicast address (#4795)

This commit includes:
- cache domain prefix in the Thread Network
- subscribe/unsubscribe AllDomainBBRs Multicast address
- update test to cover AllNetworkBBRs and AllDomainBBRs subscription

tests/scripts/thread-cert/config.py

@@ -57,6 +57,8 @@ LINK_LOCAL_ALL_NODES_ADDRESS = 'ff02::1'
 LINK_LOCAL_ALL_ROUTERS_ADDRESS = 'ff02::2'
 
 DOMAIN_PREFIX = 'fd00:7d03:7d03:7d03::/64'
+ALL_DOMAIN_BBRS_ADDRESS = 'ff32:40:fd00:7d03:7d03:7d03:0:3'
+ALL_NETWORK_BBRS_ADDRESS = 'ff32:40:fdde:ad00:beef:0:0:3'
 
 DEFAULT_MASTER_KEY = bytearray([
     0x00,

tests/scripts/thread-cert/node.py

@@ -734,6 +734,20 @@ class Node:
 
         return None
 
+    def get_ipmaddrs(self):
+        self.send_command('ipmaddr')
+        return self._expect_results(r'\S+(:\S*)+')
+
+    def has_ipmaddr(self, address):
+        ipmaddr = ipaddress.ip_address(address)
+        ipmaddrs = self.get_ipmaddrs()
+        for addr in ipmaddrs:
+            if isinstance(addr, bytearray):
+                addr = bytes(addr)
+            if ipaddress.ip_address(addr) == ipmaddr:
+                return True
+        return False
+
     def get_addr_leader_aloc(self):
         addrs = self.get_addrs()
         for addr in addrs:

tests/scripts/thread-cert/v1_2_test_backbone_router_service.py

@@ -96,7 +96,6 @@ class TestBackboneRouterService(thread_cert.TestCase):
         # 1) First Backbone Router would become the Primary.
         self.nodes[BBR_1].set_router_selection_jitter(ROUTER_SELECTION_JITTER)
         self.nodes[BBR_1].set_bbr_registration_jitter(BBR_REGISTRATION_JITTER)
-        self.nodes[BBR_1].set_domain_prefix(config.DOMAIN_PREFIX)
         self.nodes[BBR_1].set_backbone_router(seqno=1)
         self.nodes[BBR_1].start()
         WAIT_TIME = WAIT_ATTACH + ROUTER_SELECTION_JITTER
@@ -107,6 +106,13 @@ class TestBackboneRouterService(thread_cert.TestCase):
         self.simulator.go(WAIT_TIME)
         self.assertEqual(self.nodes[BBR_1].get_backbone_router_state(),
                          'Primary')
+        assert self.nodes[BBR_1].has_ipmaddr(config.ALL_NETWORK_BBRS_ADDRESS)
+        assert not self.nodes[BBR_1].has_ipmaddr(config.ALL_DOMAIN_BBRS_ADDRESS)
+
+        self.nodes[BBR_1].set_domain_prefix(config.DOMAIN_PREFIX)
+        WAIT_TIME = WAIT_REDUNDANCE
+        self.simulator.go(WAIT_TIME)
+        assert self.nodes[BBR_1].has_ipmaddr(config.ALL_DOMAIN_BBRS_ADDRESS)
 
         # 2) Reset BBR_1 and bring it back soon.
         # Verify that it restores Primary State with sequence number
@@ -172,6 +178,10 @@ class TestBackboneRouterService(thread_cert.TestCase):
         self.assertEqual(self.nodes[BBR_2].get_backbone_router_state(),
                          'Disabled')
 
+        assert not self.nodes[BBR_2].has_ipmaddr(
+            config.ALL_NETWORK_BBRS_ADDRESS)
+        assert not self.nodes[BBR_2].has_ipmaddr(config.ALL_DOMAIN_BBRS_ADDRESS)
+
         # Enable Backbone function, it will stay at Secondary state as
         # there is Primary Backbone Router already.
         # Here removes the Domain Prefix before enabling backbone function
@@ -241,6 +251,9 @@ class TestBackboneRouterService(thread_cert.TestCase):
         self.assertEqual(self.nodes[BBR_2].get_backbone_router_state(),
                          'Secondary')
 
+        assert self.nodes[BBR_1].has_ipmaddr(config.ALL_NETWORK_BBRS_ADDRESS)
+        assert self.nodes[BBR_1].has_ipmaddr(config.ALL_DOMAIN_BBRS_ADDRESS)
+
 
 if __name__ == '__main__':
     unittest.main()