X-Git-Url: https://gerrit.fd.io/r/gitweb?a=blobdiff_plain;f=test%2Ftest_ip4.py;h=589c668a45662121ddfc67732f3189a0c33b4318;hb=3d5f08a82;hp=46a8306815b8addfe8abedefc22ddc16e07a3f38;hpb=cbe25aab3be72154f2c706c39eeba6a77f34450f;p=vpp.git

diff --git a/test/test_ip4.py b/test/test_ip4.py
index 46a8306815b..589c668a456 100644
--- a/test/test_ip4.py
+++ b/test/test_ip4.py
@@ -14,13 +14,15 @@ from six import moves
 from framework import VppTestCase, VppTestRunner
 from util import ppp
 from vpp_ip_route import VppIpRoute, VppRoutePath, VppIpMRoute, \
-    VppMRoutePath, MRouteItfFlags, MRouteEntryFlags, VppMplsIpBind, \
+    VppMRoutePath, VppMplsIpBind, \
     VppMplsTable, VppIpTable, FibPathType, find_route, \
     VppIpInterfaceAddress, find_route_in_dump, find_mroute_in_dump
+from vpp_ip import VppIpPuntPolicer, VppIpPuntRedirect
 from vpp_sub_interface import VppSubInterface, VppDot1QSubint, VppDot1ADSubint
 from vpp_papi import VppEnum
 from vpp_neighbor import VppNeighbor
 from vpp_lo_interface import VppLoInterface
+from vpp_policer import VppPolicer
 
 NUM_PKTS = 67
 
@@ -213,6 +215,80 @@ class TestIPv4(VppTestCase):
             self.verify_capture(i, pkts)
 
 
+class TestIPv4RouteLookup(VppTestCase):
+    """ IPv4 Route Lookup Test Case """
+    routes = []
+
+    def route_lookup(self, prefix, exact):
+        return self.vapi.api(self.vapi.papi.ip_route_lookup,
+                             {
+                                 'table_id': 0,
+                                 'exact': exact,
+                                 'prefix': prefix,
+                             })
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestIPv4RouteLookup, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestIPv4RouteLookup, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestIPv4RouteLookup, self).setUp()
+
+        drop_nh = VppRoutePath("127.0.0.1", 0xffffffff,
+                               type=FibPathType.FIB_PATH_TYPE_DROP)
+
+        # Add 3 routes
+        r = VppIpRoute(self, "1.1.0.0", 16, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "1.1.1.0", 24, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+        r = VppIpRoute(self, "1.1.1.1", 32, [drop_nh])
+        r.add_vpp_config()
+        self.routes.append(r)
+
+    def tearDown(self):
+        # Remove the routes we added
+        for r in self.routes:
+            r.remove_vpp_config()
+
+        super(TestIPv4RouteLookup, self).tearDown()
+
+    def test_exact_match(self):
+        # Verify we find the host route
+        prefix = "1.1.1.1/32"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we find a middle prefix route
+        prefix = "1.1.1.0/24"
+        result = self.route_lookup(prefix, True)
+        assert (prefix == str(result.route.prefix))
+
+        # Verify we do not find an available LPM.
+        with self.vapi.assert_negative_api_retval():
+            self.route_lookup("1.1.1.2/32", True)
+
+    def test_longest_prefix_match(self):
+        # verify we find lpm
+        lpm_prefix = "1.1.1.0/24"
+        result = self.route_lookup("1.1.1.2/32", False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Verify we find the exact when not requested
+        result = self.route_lookup(lpm_prefix, False)
+        assert (lpm_prefix == str(result.route.prefix))
+
+        # Can't seem to delete the default route so no negative LPM test.
+
+
 class TestIPv4IfAddrRoute(VppTestCase):
     """ IPv4 Interface Addr Route Test Case """
 
@@ -336,6 +412,24 @@ class TestIPv4IfAddrRoute(VppTestCase):
         fib4_dump = self.vapi.ip_route_dump(0)
         self.assertTrue(lo_if.is_ip4_entry_in_fib_dump(fib4_dump))
 
+    def test_ipv4_ifaddr_del(self):
+        """ Delete an interface address that does not exist """
+
+        loopbacks = self.create_loopback_interfaces(1)
+        lo = self.lo_interfaces[0]
+
+        lo.config_ip4()
+        lo.admin_up()
+
+        #
+        # try and remove pg0's subnet from lo
+        #
+        with self.vapi.assert_negative_api_retval():
+            self.vapi.sw_interface_add_del_address(
+                sw_if_index=lo.sw_if_index,
+                prefix=self.pg0.local_ip4_prefix,
+                is_add=0)
+
 
 class TestICMPEcho(VppTestCase):
     """ ICMP Echo Test Case """
@@ -803,6 +897,9 @@ class TestIPDisabled(VppTestCase):
     def test_ip_disabled(self):
         """ IP Disabled """
 
+        MRouteItfFlags = VppEnum.vl_api_mfib_itf_flags_t
+        MRouteEntryFlags = VppEnum.vl_api_mfib_entry_flags_t
+
         #
         # An (S,G).
         # one accepting interface, pg0, 2 forwarding interfaces
@@ -811,11 +908,11 @@ class TestIPDisabled(VppTestCase):
             self,
             "0.0.0.0",
             "232.1.1.1", 32,
-            MRouteEntryFlags.MFIB_ENTRY_FLAG_NONE,
+            MRouteEntryFlags.MFIB_API_ENTRY_FLAG_NONE,
             [VppMRoutePath(self.pg1.sw_if_index,
-                           MRouteItfFlags.MFIB_ITF_FLAG_ACCEPT),
+                           MRouteItfFlags.MFIB_API_ITF_FLAG_ACCEPT),
              VppMRoutePath(self.pg0.sw_if_index,
-                           MRouteItfFlags.MFIB_ITF_FLAG_FORWARD)])
+                           MRouteItfFlags.MFIB_API_ITF_FLAG_FORWARD)])
         route_232_1_1_1.add_vpp_config()
 
         pu = (Ether(src=self.pg1.remote_mac,
@@ -1021,6 +1118,7 @@ class TestIPLoadBalance(VppTestCase):
         super(TestIPLoadBalance, self).tearDown()
 
     def send_and_expect_load_balancing(self, input, pkts, outputs):
+        self.vapi.cli("clear trace")
         input.add_stream(pkts)
         self.pg_enable_capture(self.pg_interfaces)
         self.pg_start()
@@ -1028,8 +1126,7 @@ class TestIPLoadBalance(VppTestCase):
         for oo in outputs:
             rx = oo._get_capture(1)
             self.assertNotEqual(0, len(rx))
-            for r in rx:
-                rxs.append(r)
+            rxs.append(rx)
         return rxs
 
     def send_and_expect_one_itf(self, input, pkts, itf):
@@ -1038,9 +1135,18 @@ class TestIPLoadBalance(VppTestCase):
         self.pg_start()
         rx = itf.get_capture(len(pkts))
 
+    def total_len(self, rxs):
+        n = 0
+        for rx in rxs:
+            n += len(rx)
+        return n
+
     def test_ip_load_balance(self):
         """ IP Load-Balancing """
 
+        fhc = VppEnum.vl_api_ip_flow_hash_config_t
+        af = VppEnum.vl_api_address_family_t
+
         #
         # An array of packets that differ only in the destination port
         #
@@ -1095,21 +1201,41 @@ class TestIPLoadBalance(VppTestCase):
         # be guaranteed. But with 64 different packets we do expect some
         # balancing. So instead just ensure there is traffic on each link.
         #
-        self.send_and_expect_load_balancing(self.pg0, port_ip_pkts,
-                                            [self.pg1, self.pg2])
+        rx = self.send_and_expect_load_balancing(self.pg0, port_ip_pkts,
+                                                 [self.pg1, self.pg2])
+        n_ip_pg0 = len(rx[0])
         self.send_and_expect_load_balancing(self.pg0, src_ip_pkts,
                                             [self.pg1, self.pg2])
         self.send_and_expect_load_balancing(self.pg0, port_mpls_pkts,
                                             [self.pg1, self.pg2])
-        self.send_and_expect_load_balancing(self.pg0, src_mpls_pkts,
-                                            [self.pg1, self.pg2])
+        rx = self.send_and_expect_load_balancing(self.pg0, src_mpls_pkts,
+                                                 [self.pg1, self.pg2])
+        n_mpls_pg0 = len(rx[0])
+
+        #
+        # change the router ID and expect the distribution changes
+        #
+        self.vapi.set_ip_flow_hash_router_id(router_id=0x11111111)
+
+        rx = self.send_and_expect_load_balancing(self.pg0, port_ip_pkts,
+                                                 [self.pg1, self.pg2])
+        self.assertNotEqual(n_ip_pg0, len(rx[0]))
+
+        rx = self.send_and_expect_load_balancing(self.pg0, src_mpls_pkts,
+                                                 [self.pg1, self.pg2])
+        self.assertNotEqual(n_mpls_pg0, len(rx[0]))
 
         #
         # change the flow hash config so it's only IP src,dst
         #  - now only the stream with differing source address will
         #    load-balance
         #
-        self.vapi.set_ip_flow_hash(vrf_id=0, src=1, dst=1, sport=0, dport=0)
+        self.vapi.set_ip_flow_hash_v2(
+            af=af.ADDRESS_IP4,
+            table_id=0,
+            flow_hash_config=(fhc.IP_API_FLOW_HASH_SRC_IP |
+                              fhc.IP_API_FLOW_HASH_DST_IP |
+                              fhc.IP_API_FLOW_HASH_PROTO))
 
         self.send_and_expect_load_balancing(self.pg0, src_ip_pkts,
                                             [self.pg1, self.pg2])
@@ -1121,7 +1247,8 @@ class TestIPLoadBalance(VppTestCase):
         #
         # change the flow hash config back to defaults
         #
-        self.vapi.set_ip_flow_hash(vrf_id=0, src=1, dst=1, sport=1, dport=1)
+        self.vapi.set_ip_flow_hash(vrf_id=0, src=1, dst=1,
+                                   proto=1, sport=1, dport=1)
 
         #
         # Recursive prefixes
@@ -1167,23 +1294,23 @@ class TestIPLoadBalance(VppTestCase):
                                              self.pg3, self.pg4])
 
         #
-        # bring down pg1 expect LB to adjust to use only those that are pu
+        # bring down pg1 expect LB to adjust to use only those that are up
         #
         self.pg1.link_down()
 
         rx = self.send_and_expect_load_balancing(self.pg0, src_pkts,
                                                  [self.pg2, self.pg3,
                                                   self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
 
         #
-        # bring down pg2 expect LB to adjust to use only those that are pu
+        # bring down pg2 expect LB to adjust to use only those that are up
         #
         self.pg2.link_down()
 
         rx = self.send_and_expect_load_balancing(self.pg0, src_pkts,
                                                  [self.pg3, self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
 
         #
         # bring the links back up - expect LB over all again
@@ -1194,7 +1321,7 @@ class TestIPLoadBalance(VppTestCase):
         rx = self.send_and_expect_load_balancing(self.pg0, src_pkts,
                                                  [self.pg1, self.pg2,
                                                   self.pg3, self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
 
         #
         # The same link-up/down but this time admin state
@@ -1203,7 +1330,7 @@ class TestIPLoadBalance(VppTestCase):
         self.pg2.admin_down()
         rx = self.send_and_expect_load_balancing(self.pg0, src_pkts,
                                                  [self.pg3, self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
         self.pg1.admin_up()
         self.pg2.admin_up()
         self.pg1.resolve_arp()
@@ -1211,7 +1338,7 @@ class TestIPLoadBalance(VppTestCase):
         rx = self.send_and_expect_load_balancing(self.pg0, src_pkts,
                                                  [self.pg1, self.pg2,
                                                   self.pg3, self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
 
         #
         # Recursive prefixes
@@ -1269,7 +1396,7 @@ class TestIPLoadBalance(VppTestCase):
 
         rx = self.send_and_expect_load_balancing(self.pg0, port_pkts,
                                                  [self.pg3, self.pg4])
-        self.assertEqual(len(src_pkts), len(rx))
+        self.assertEqual(len(src_pkts), self.total_len(rx))
 
 
 class TestIPVlan0(VppTestCase):
@@ -1381,18 +1508,19 @@ class TestIPPunt(VppTestCase):
         # Configure a punt redirect via pg1.
         #
         nh_addr = self.pg1.remote_ip4
-        self.vapi.ip_punt_redirect(self.pg0.sw_if_index,
-                                   self.pg1.sw_if_index,
-                                   nh_addr)
+        ip_punt_redirect = VppIpPuntRedirect(self, self.pg0.sw_if_index,
+                                             self.pg1.sw_if_index, nh_addr)
+        ip_punt_redirect.add_vpp_config()
 
         self.send_and_expect(self.pg0, pkts, self.pg1)
 
         #
         # add a policer
         #
-        policer = self.vapi.policer_add_del(b"ip4-punt", 400, 0, 10, 0,
-                                            rate_type=1)
-        self.vapi.ip_punt_police(policer.policer_index)
+        policer = VppPolicer(self, "ip4-punt", 400, 0, 10, 0, rate_type=1)
+        policer.add_vpp_config()
+        ip_punt_policer = VppIpPuntPolicer(self, policer.policer_index)
+        ip_punt_policer.add_vpp_config()
 
         self.vapi.cli("clear trace")
         self.pg0.add_stream(pkts)
@@ -1410,33 +1538,25 @@ class TestIPPunt(VppTestCase):
         #
         # remove the policer. back to full rx
         #
-        self.vapi.ip_punt_police(policer.policer_index, is_add=0)
-        self.vapi.policer_add_del(b"ip4-punt", 400, 0, 10, 0,
-                                  rate_type=1, is_add=0)
+        ip_punt_policer.remove_vpp_config()
+        policer.remove_vpp_config()
         self.send_and_expect(self.pg0, pkts, self.pg1)
 
         #
         # remove the redirect. expect full drop.
         #
-        self.vapi.ip_punt_redirect(self.pg0.sw_if_index,
-                                   self.pg1.sw_if_index,
-                                   nh_addr,
-                                   is_add=0)
+        ip_punt_redirect.remove_vpp_config()
         self.send_and_assert_no_replies(self.pg0, pkts,
                                         "IP no punt config")
 
         #
         # Add a redirect that is not input port selective
         #
-        self.vapi.ip_punt_redirect(0xffffffff,
-                                   self.pg1.sw_if_index,
-                                   nh_addr)
+        ip_punt_redirect = VppIpPuntRedirect(self, 0xffffffff,
+                                             self.pg1.sw_if_index, nh_addr)
+        ip_punt_redirect.add_vpp_config()
         self.send_and_expect(self.pg0, pkts, self.pg1)
-
-        self.vapi.ip_punt_redirect(0xffffffff,
-                                   self.pg1.sw_if_index,
-                                   nh_addr,
-                                   is_add=0)
+        ip_punt_redirect.remove_vpp_config()
 
     def test_ip_punt_dump(self):
         """ IP4 punt redirect dump"""
@@ -1445,22 +1565,22 @@ class TestIPPunt(VppTestCase):
         # Configure a punt redirects
         #
         nh_address = self.pg3.remote_ip4
-        self.vapi.ip_punt_redirect(self.pg0.sw_if_index,
-                                   self.pg3.sw_if_index,
-                                   nh_address)
-        self.vapi.ip_punt_redirect(self.pg1.sw_if_index,
-                                   self.pg3.sw_if_index,
-                                   nh_address)
-        self.vapi.ip_punt_redirect(self.pg2.sw_if_index,
-                                   self.pg3.sw_if_index,
-                                   '0.0.0.0')
+        ipr_03 = VppIpPuntRedirect(self, self.pg0.sw_if_index,
+                                   self.pg3.sw_if_index, nh_address)
+        ipr_13 = VppIpPuntRedirect(self, self.pg1.sw_if_index,
+                                   self.pg3.sw_if_index, nh_address)
+        ipr_23 = VppIpPuntRedirect(self, self.pg2.sw_if_index,
+                                   self.pg3.sw_if_index, "0.0.0.0")
+        ipr_03.add_vpp_config()
+        ipr_13.add_vpp_config()
+        ipr_23.add_vpp_config()
 
         #
         # Dump pg0 punt redirects
         #
-        punts = self.vapi.ip_punt_redirect_dump(self.pg0.sw_if_index)
-        for p in punts:
-            self.assertEqual(p.punt.rx_sw_if_index, self.pg0.sw_if_index)
+        self.assertTrue(ipr_03.query_vpp_config())
+        self.assertTrue(ipr_13.query_vpp_config())
+        self.assertTrue(ipr_23.query_vpp_config())
 
         #
         # Dump punt redirects for all interfaces
@@ -1998,6 +2118,8 @@ class TestIPReplace(VppTestCase):
     def test_replace(self):
         """ IP Table Replace """
 
+        MRouteItfFlags = VppEnum.vl_api_mfib_itf_flags_t
+        MRouteEntryFlags = VppEnum.vl_api_mfib_entry_flags_t
         N_ROUTES = 20
         links = [self.pg0, self.pg1, self.pg2, self.pg3]
         routes = [[], [], [], []]
@@ -2015,15 +2137,15 @@ class TestIPReplace(VppTestCase):
                 multi = VppIpMRoute(
                     self, "0.0.0.0",
                     "239.0.0.%d" % jj, 32,
-                    MRouteEntryFlags.MFIB_ENTRY_FLAG_NONE,
+                    MRouteEntryFlags.MFIB_API_ENTRY_FLAG_NONE,
                     [VppMRoutePath(self.pg0.sw_if_index,
-                                   MRouteItfFlags.MFIB_ITF_FLAG_ACCEPT),
+                                   MRouteItfFlags.MFIB_API_ITF_FLAG_ACCEPT),
                      VppMRoutePath(self.pg1.sw_if_index,
-                                   MRouteItfFlags.MFIB_ITF_FLAG_FORWARD),
+                                   MRouteItfFlags.MFIB_API_ITF_FLAG_FORWARD),
                      VppMRoutePath(self.pg2.sw_if_index,
-                                   MRouteItfFlags.MFIB_ITF_FLAG_FORWARD),
+                                   MRouteItfFlags.MFIB_API_ITF_FLAG_FORWARD),
                      VppMRoutePath(self.pg3.sw_if_index,
-                                   MRouteItfFlags.MFIB_ITF_FLAG_FORWARD)],
+                                   MRouteItfFlags.MFIB_API_ITF_FLAG_FORWARD)],
                     table_id=t.table_id).add_vpp_config()
                 routes[ii].append({'uni': uni,
                                    'multi': multi})
@@ -2089,7 +2211,7 @@ class TestIPReplace(VppTestCase):
         for t in self.tables:
             t.flush()
             self.assertEqual(len(t.dump()), 5)
-            self.assertEqual(len(t.mdump()), 1)
+            self.assertEqual(len(t.mdump()), 3)
 
 
 class TestIPCover(VppTestCase):
@@ -2146,14 +2268,180 @@ class TestIPCover(VppTestCase):
                        register=False).add_vpp_config()
 
         # add/remove/add a longer mask cover
-        r = VppIpRoute(self, "127.0.0.0", 8,
-                       [VppRoutePath("127.0.0.1",
-                                     lo.sw_if_index)]).add_vpp_config()
-        r.remove_vpp_config()
-        r.add_vpp_config()
+        r8 = VppIpRoute(self, "127.0.0.0", 8,
+                        [VppRoutePath("127.0.0.1",
+                                      lo.sw_if_index)]).add_vpp_config()
+        r8.remove_vpp_config()
+        r8.add_vpp_config()
+        r8.remove_vpp_config()
 
         # remove the default route
         r.remove_vpp_config()
 
+        # remove the interface prefix
+        a.remove_vpp_config()
+
+
+class TestIP4Replace(VppTestCase):
+    """ IPv4 Interface Address Replace """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestIP4Replace, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestIP4Replace, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestIP4Replace, self).setUp()
+
+        self.create_pg_interfaces(range(4))
+
+        for i in self.pg_interfaces:
+            i.admin_up()
+
+    def tearDown(self):
+        super(TestIP4Replace, self).tearDown()
+        for i in self.pg_interfaces:
+            i.admin_down()
+
+    def get_n_pfxs(self, intf):
+        return len(self.vapi.ip_address_dump(intf.sw_if_index))
+
+    def test_replace(self):
+        """ IP interface address replace """
+
+        intf_pfxs = [[], [], [], []]
+
+        # add prefixes to each of the interfaces
+        for i in range(len(self.pg_interfaces)):
+            intf = self.pg_interfaces[i]
+
+            # 172.16.x.1/24
+            addr = "172.16.%d.1" % intf.sw_if_index
+            a = VppIpInterfaceAddress(self, intf, addr, 24).add_vpp_config()
+            intf_pfxs[i].append(a)
+
+            # 172.16.x.2/24 - a different address in the same subnet as above
+            addr = "172.16.%d.2" % intf.sw_if_index
+            a = VppIpInterfaceAddress(self, intf, addr, 24).add_vpp_config()
+            intf_pfxs[i].append(a)
+
+            # 172.15.x.2/24 - a different address and subnet
+            addr = "172.15.%d.2" % intf.sw_if_index
+            a = VppIpInterfaceAddress(self, intf, addr, 24).add_vpp_config()
+            intf_pfxs[i].append(a)
+
+        # a dump should n_address in it
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 3)
+
+        #
+        # remove all the address thru a replace
+        #
+        self.vapi.sw_interface_address_replace_begin()
+        self.vapi.sw_interface_address_replace_end()
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 0)
+
+        #
+        # add all the interface addresses back
+        #
+        for p in intf_pfxs:
+            for v in p:
+                v.add_vpp_config()
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 3)
+
+        #
+        # replace again, but this time update/re-add the address on the first
+        # two interfaces
+        #
+        self.vapi.sw_interface_address_replace_begin()
+
+        for p in intf_pfxs[:2]:
+            for v in p:
+                v.add_vpp_config()
+
+        self.vapi.sw_interface_address_replace_end()
+
+        # on the first two the address still exist,
+        # on the other two they do not
+        for intf in self.pg_interfaces[:2]:
+            self.assertEqual(self.get_n_pfxs(intf), 3)
+        for p in intf_pfxs[:2]:
+            for v in p:
+                self.assertTrue(v.query_vpp_config())
+        for intf in self.pg_interfaces[2:]:
+            self.assertEqual(self.get_n_pfxs(intf), 0)
+
+        #
+        # add all the interface addresses back on the last two
+        #
+        for p in intf_pfxs[2:]:
+            for v in p:
+                v.add_vpp_config()
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 3)
+
+        #
+        # replace again, this time add different prefixes on all the interfaces
+        #
+        self.vapi.sw_interface_address_replace_begin()
+
+        pfxs = []
+        for intf in self.pg_interfaces:
+            # 172.18.x.1/24
+            addr = "172.18.%d.1" % intf.sw_if_index
+            pfxs.append(VppIpInterfaceAddress(self, intf, addr,
+                                              24).add_vpp_config())
+
+        self.vapi.sw_interface_address_replace_end()
+
+        # only .18 should exist on each interface
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 1)
+        for pfx in pfxs:
+            self.assertTrue(pfx.query_vpp_config())
+
+        #
+        # remove everything
+        #
+        self.vapi.sw_interface_address_replace_begin()
+        self.vapi.sw_interface_address_replace_end()
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 0)
+
+        #
+        # add prefixes to each interface. post-begin add the prefix from
+        # interface X onto interface Y. this would normally be an error
+        # since it would generate a 'duplicate address' warning. but in
+        # this case, since what is newly downloaded is sane, it's ok
+        #
+        for intf in self.pg_interfaces:
+            # 172.18.x.1/24
+            addr = "172.18.%d.1" % intf.sw_if_index
+            VppIpInterfaceAddress(self, intf, addr, 24).add_vpp_config()
+
+        self.vapi.sw_interface_address_replace_begin()
+
+        pfxs = []
+        for intf in self.pg_interfaces:
+            # 172.18.x.1/24
+            addr = "172.18.%d.1" % (intf.sw_if_index + 1)
+            pfxs.append(VppIpInterfaceAddress(self, intf,
+                                              addr, 24).add_vpp_config())
+
+        self.vapi.sw_interface_address_replace_end()
+
+        self.logger.info(self.vapi.cli("sh int addr"))
+
+        for intf in self.pg_interfaces:
+            self.assertEqual(self.get_n_pfxs(intf), 1)
+        for pfx in pfxs:
+            self.assertTrue(pfx.query_vpp_config())
+
+
 if __name__ == '__main__':
     unittest.main(testRunner=VppTestRunner)