ip: allow addrs from the same prefix on intf

Type: feature

Adding a prefix to an interface was not permitted if it overlapped
with another prefix on an interface which used the same FIB.

Loosen the restriction. Allow 2 or more addresses from the same
prefix on a single interface. Reference count the prefix to figure
out when a glean/connected route for the prefix needs to be added
or removed.

Added unit tests to check that the route is only removed when all
addresses in the prefix are removed from the interface.

Change-Id: I1a962ecb5e1ee65fc6d41f98a4cc097a51a55321
Signed-off-by: Matthew Smith <mgsmith@netgate.com>

test/test_ip4.py

@@ -15,7 +15,9 @@ from framework import VppTestCase, VppTestRunner
 from util import ppp
 from vpp_ip_route import VppIpRoute, VppRoutePath, VppIpMRoute, \
     VppMRoutePath, MRouteItfFlags, MRouteEntryFlags, VppMplsIpBind, \
-    VppMplsTable, VppIpTable, FibPathType, find_route
+    VppMplsTable, VppIpTable, FibPathType, find_route, \
+    VppIpInterfaceAddress
+from vpp_ip import VppIpAddress
 from vpp_sub_interface import VppSubInterface, VppDot1QSubint, VppDot1ADSubint
 from vpp_papi import VppEnum
 
@@ -210,19 +212,19 @@ class TestIPv4(VppTestCase):
             self.verify_capture(i, pkts)
 
 
-class TestIPV4IfAddrRoute(VppTestCase):
+class TestIPv4IfAddrRoute(VppTestCase):
     """ IPv4 Interface Addr Route Test Case """
 
     @classmethod
     def setUpClass(cls):
-        super(TestIPV4IfAddrRoute, cls).setUpClass()
+        super(TestIPv4IfAddrRoute, cls).setUpClass()
 
     @classmethod
     def tearDownClass(cls):
-        super(TestIPV4IfAddrRoute, cls).tearDownClass()
+        super(TestIPv4IfAddrRoute, cls).tearDownClass()
 
     def setUp(self):
-        super(TestIPV4IfAddrRoute, self).setUp()
+        super(TestIPv4IfAddrRoute, self).setUp()
 
         # create 1 pg interface
         self.create_pg_interfaces(range(1))
@@ -233,11 +235,62 @@ class TestIPV4IfAddrRoute(VppTestCase):
             i.resolve_arp()
 
     def tearDown(self):
-        super(TestIPV4IfAddrRoute, self).tearDown()
+        super(TestIPv4IfAddrRoute, self).tearDown()
         for i in self.pg_interfaces:
             i.unconfig_ip4()
             i.admin_down()
 
+    def test_ipv4_ifaddrs_same_prefix(self):
+        """ IPv4 Interface Addresses Same Prefix test
+
+        Test scenario:
+
+            - Verify no route in FIB for prefix 10.10.10.0/24
+            - Configure IPv4 address 10.10.10.10/24 on an interface
+            - Verify route in FIB for prefix 10.10.10.0/24
+            - Configure IPv4 address 10.10.10.20/24 on an interface
+            - Delete 10.10.10.10/24 from interface
+            - Verify route in FIB for prefix 10.10.10.0/24
+            - Delete 10.10.10.20/24 from interface
+            - Verify no route in FIB for prefix 10.10.10.0/24
+        """
+
+        # create two addresses, verify route not present
+        if_addr1 = VppIpInterfaceAddress(self, self.pg0,
+                                         VppIpAddress("10.10.10.10"), 24)
+        if_addr2 = VppIpInterfaceAddress(self, self.pg0,
+                                         VppIpAddress("10.10.10.20"), 24)
+        self.assertFalse(if_addr1.query_vpp_config())  # 10.10.10.0/24
+        self.assertFalse(find_route(self, "10.10.10.10", 32))
+        self.assertFalse(find_route(self, "10.10.10.20", 32))
+        self.assertFalse(find_route(self, "10.10.10.255", 32))
+        self.assertFalse(find_route(self, "10.10.10.0", 32))
+
+        # configure first address, verify route present
+        if_addr1.add_vpp_config()
+        self.assertTrue(if_addr1.query_vpp_config())  # 10.10.10.0/24
+        self.assertTrue(find_route(self, "10.10.10.10", 32))
+        self.assertFalse(find_route(self, "10.10.10.20", 32))
+        self.assertTrue(find_route(self, "10.10.10.255", 32))
+        self.assertTrue(find_route(self, "10.10.10.0", 32))
+
+        # configure second address, delete first, verify route not removed
+        if_addr2.add_vpp_config()
+        if_addr1.remove_vpp_config()
+        self.assertTrue(if_addr1.query_vpp_config())  # 10.10.10.0/24
+        self.assertFalse(find_route(self, "10.10.10.10", 32))
+        self.assertTrue(find_route(self, "10.10.10.20", 32))
+        self.assertTrue(find_route(self, "10.10.10.255", 32))
+        self.assertTrue(find_route(self, "10.10.10.0", 32))
+
+        # delete second address, verify route removed
+        if_addr2.remove_vpp_config()
+        self.assertFalse(if_addr1.query_vpp_config())  # 10.10.10.0/24
+        self.assertFalse(find_route(self, "10.10.10.10", 32))
+        self.assertFalse(find_route(self, "10.10.10.20", 32))
+        self.assertFalse(find_route(self, "10.10.10.255", 32))
+        self.assertFalse(find_route(self, "10.10.10.0", 32))
+
     def test_ipv4_ifaddr_route(self):
         """ IPv4 Interface Address Route test