vrrp: add plugin providing vrrp support

Type: feature

Add a new plugin to support HA using VRRPv3 (RFC 5798).

Change-Id: Iaa2c37e6172f8f41e9165f178f44d481f6e247b9
Signed-off-by: Matthew Smith <mgsmith@netgate.com>

1 files changed, 1288 insertions, 0 deletions

diff --git a/src/plugins/vrrp/test/test_vrrp.py b/src/plugins/vrrp/test/test_vrrp.py
new file mode 100644
index 00000000000..cc46a1de5f4
--- /dev/null
+++ b/src/plugins/vrrp/test/test_vrrp.py
@@ -0,0 +1,1288 @@
+#!/usr/bin/env python3
+
+#
+# Copyright 2019-2020 Rubicon Communications, LLC (Netgate)
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+import unittest
+import time
+from socket import inet_pton, inet_ntop, AF_INET6
+
+from vpp_object import VppObject
+from vpp_papi import VppEnum
+
+from scapy.packet import Raw
+from scapy.layers.l2 import Ether, ARP
+from scapy.layers.inet import IP, ICMP, icmptypes
+from scapy.layers.inet6 import IPv6, ipv6nh, IPv6ExtHdrHopByHop, \
+    ICMPv6MLReport2, ICMPv6ND_NA, ICMPv6ND_NS, ICMPv6NDOptDstLLAddr, \
+    ICMPv6NDOptSrcLLAddr, ICMPv6EchoRequest, ICMPv6EchoReply
+from scapy.contrib.igmpv3 import IGMPv3, IGMPv3mr, IGMPv3gr
+from scapy.layers.vrrp import IPPROTO_VRRP, VRRPv3
+from scapy.utils6 import in6_getnsma, in6_getnsmac
+from framework import VppTestCase, VppTestRunner
+from util import ip6_normalize
+
+VRRP_VR_FLAG_PREEMPT = 1
+VRRP_VR_FLAG_ACCEPT = 2
+VRRP_VR_FLAG_UNICAST = 4
+VRRP_VR_FLAG_IPV6 = 8
+
+VRRP_VR_STATE_INIT = 0
+VRRP_VR_STATE_BACKUP = 1
+VRRP_VR_STATE_MASTER = 2
+VRRP_VR_STATE_INTF_DOWN = 3
+
+
+def is_non_arp(p):
+    """ Want to filter out advertisements, igmp, etc"""
+    if p.haslayer(ARP):
+        return False
+
+    return True
+
+
+def is_not_adv(p):
+    """ Filter out everything but advertisements. E.g. multicast RD/ND """
+    if p.haslayer(VRRPv3):
+        return False
+
+    return True
+
+
+def is_not_echo_reply(p):
+    """ filter out advertisements and other while waiting for echo reply """
+    if p.haslayer(IP) and p.haslayer(ICMP):
+        if icmptypes[p[ICMP].type] == "echo-reply":
+            return False
+    elif p.haslayer(IPv6) and p.haslayer(ICMPv6EchoReply):
+        return False
+
+    return True
+
+
+class VppVRRPVirtualRouter(VppObject):
+
+    def __init__(self,
+                 test,
+                 intf,
+                 vr_id,
+                 prio=100,
+                 intvl=100,
+                 flags=VRRP_VR_FLAG_PREEMPT,
+                 vips=None):
+        self._test = test
+        self._intf = intf
+        self._sw_if_index = self._intf.sw_if_index
+        self._vr_id = vr_id
+        self._prio = prio
+        self._intvl = intvl
+        self._flags = flags
+        if (flags & VRRP_VR_FLAG_IPV6):
+            self._is_ipv6 = 1
+            self._adv_dest_mac = "33:33:00:00:00:12"
+            self._virtual_mac = "00:00:5e:00:02:%02x" % vr_id
+            self._adv_dest_ip = "ff02::12"
+            self._vips = ([intf.local_ip6] if vips is None else vips)
+        else:
+            self._is_ipv6 = 0
+            self._adv_dest_mac = "01:00:5e:00:00:12"
+            self._virtual_mac = "00:00:5e:00:01:%02x" % vr_id
+            self._adv_dest_ip = "224.0.0.18"
+            self._vips = ([intf.local_ip4] if vips is None else vips)
+        self._tracked_ifs = []
+
+    def add_vpp_config(self):
+        self._test.vapi.vrrp_vr_add_del(is_add=1,
+                                        sw_if_index=self._intf.sw_if_index,
+                                        vr_id=self._vr_id,
+                                        priority=self._prio,
+                                        interval=self._intvl,
+                                        flags=self._flags,
+                                        n_addrs=len(self._vips),
+                                        addrs=self._vips)
+
+    def query_vpp_config(self):
+        vrs = self._test.vapi.vrrp_vr_dump(sw_if_index=self._intf.sw_if_index)
+        for vr in vrs:
+            if vr.config.vr_id != self._vr_id:
+                continue
+
+            is_ipv6 = (1 if (vr.config.flags & VRRP_VR_FLAG_IPV6) else 0)
+            if is_ipv6 != self._is_ipv6:
+                continue
+
+            return vr
+
+        return None
+
+    def remove_vpp_config(self):
+        self._test.vapi.vrrp_vr_add_del(is_add=0,
+                                        sw_if_index=self._intf.sw_if_index,
+                                        vr_id=self._vr_id,
+                                        priority=self._prio,
+                                        interval=self._intvl,
+                                        flags=self._flags,
+                                        n_addrs=len(self._vips),
+                                        addrs=self._vips)
+
+    def start_stop(self, is_start):
+        self._test.vapi.vrrp_vr_start_stop(is_start=is_start,
+                                           sw_if_index=self._intf.sw_if_index,
+                                           vr_id=self._vr_id,
+                                           is_ipv6=self._is_ipv6)
+        self._start_time = (time.time() if is_start else None)
+
+    def add_del_tracked_interface(self, is_add, sw_if_index, prio):
+        args = {
+            'sw_if_index': self._intf.sw_if_index,
+            'is_ipv6': self._is_ipv6,
+            'vr_id': self._vr_id,
+            'is_add': is_add,
+            'n_ifs': 1,
+            'ifs': [{'sw_if_index': sw_if_index, 'priority': prio}]
+        }
+        self._test.vapi.vrrp_vr_track_if_add_del(**args)
+        self._tracked_ifs.append(args['ifs'][0])
+
+    def set_unicast_peers(self, addrs):
+        args = {
+            'sw_if_index': self._intf.sw_if_index,
+            'is_ipv6': self._is_ipv6,
+            'vr_id': self._vr_id,
+            'n_addrs': len(addrs),
+            'addrs': addrs
+        }
+        self._test.vapi.vrrp_vr_set_peers(**args)
+        self._unicast_peers = addrs
+
+    def vrrp_adv_packet(self, prio=None, src_ip=None):
+        dst_ip = self._adv_dest_ip
+        if prio is None:
+            prio = self._prio
+        eth = Ether(dst=self._adv_dest_mac, src=self._virtual_mac)
+        vrrp = VRRPv3(vrid=self._vr_id, priority=prio,
+                      ipcount=len(self._vips), adv=self._intvl)
+        if self._is_ipv6:
+            src_ip = (self._intf.local_ip6_ll if src_ip is None else src_ip)
+            ip = IPv6(src=src_ip, dst=dst_ip, nh=IPPROTO_VRRP, hlim=255)
+            vrrp.addrlist = self._vips
+        else:
+            src_ip = (self._intf.local_ip4 if src_ip is None else src_ip)
+            ip = IP(src=src_ip, dst=dst_ip, proto=IPPROTO_VRRP, ttl=255, id=0)
+            vrrp.addrlist = self._vips
+
+        # Fill in default values & checksums
+        pkt = Ether(raw(eth / ip / vrrp))
+        return pkt
+
+    def start_time(self):
+        return self._start_time
+
+    def virtual_mac(self):
+        return self._virtual_mac
+
+    def virtual_ips(self):
+        return self._vips
+
+    def adv_dest_mac(self):
+        return self._adv_dest_mac
+
+    def adv_dest_ip(self):
+        return self._adv_dest_ip
+
+    def priority(self):
+        return self._prio
+
+    def vr_id(self):
+        return self._vr_id
+
+    def adv_interval(self):
+        return self._intvl
+
+    def interface(self):
+        return self._intf
+
+    def assert_state_equals(self, state):
+        vr_details = self.query_vpp_config()
+        self._test.assertEqual(vr_details.runtime.state, state)
+
+    def master_down_seconds(self):
+        vr_details = self.query_vpp_config()
+        return (vr_details.runtime.master_down_int * 0.01)
+
+
+class TestVRRP4(VppTestCase):
+    """ IPv4 VRRP Test Case """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestVRRP4, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestVRRP4, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestVRRP4, self).setUp()
+
+        self.create_pg_interfaces(range(2))
+
+        for i in self.pg_interfaces:
+            i.admin_up()
+            i.config_ip4()
+            i.generate_remote_hosts(5)
+            i.configure_ipv4_neighbors()
+
+        self._vrs = []
+        self._default_flags = VRRP_VR_FLAG_PREEMPT
+        self._default_adv = 100
+
+    def tearDown(self):
+        for vr in self._vrs:
+            try:
+                vr_api = vr.query_vpp_config()
+                if vr_api.runtime.state != VRRP_VR_STATE_INIT:
+                    vr.start_stop(is_start=0)
+                vr.remove_vpp_config()
+            except:
+                self.logger.error("Error cleaning up")
+
+        for i in self.pg_interfaces:
+            i.admin_down()
+            i.unconfig_ip4()
+            i.unconfig_ip6()
+
+        self._vrs = []
+
+        super(TestVRRP4, self).tearDown()
+
+    def verify_vrrp4_igmp(self, pkt):
+        ip = pkt[IP]
+        self.assertEqual(ip.dst, "224.0.0.22")
+        self.assertEqual(ip.proto, 2)
+
+        igmp = pkt[IGMPv3]
+        self.assertEqual(IGMPv3.igmpv3types[igmp.type],
+                         "Version 3 Membership Report")
+
+        igmpmr = pkt[IGMPv3mr]
+        self.assertEqual(igmpmr.numgrp, 1)
+        self.assertEqual(igmpmr.records[0].maddr, "224.0.0.18")
+
+    def verify_vrrp4_garp(self, pkt, vip, vmac):
+        arp = pkt[ARP]
+
+        # ARP "who-has" op == 1
+        self.assertEqual(arp.op, 1)
+        self.assertEqual(arp.pdst, arp.psrc)
+        self.assertEqual(arp.pdst, vip)
+        self.assertEqual(arp.hwsrc, vmac)
+
+    def verify_vrrp4_adv(self, rx_pkt, vr, prio=None):
+        vips = vr.virtual_ips()
+        eth = rx_pkt[Ether]
+        ip = rx_pkt[IP]
+        vrrp = rx_pkt[VRRPv3]
+
+        pkt = vr.vrrp_adv_packet(prio=prio)
+
+        # Source MAC is virtual MAC, destination is multicast MAC
+        self.assertEqual(eth.src, vr.virtual_mac())
+        self.assertEqual(eth.dst, vr.adv_dest_mac())
+
+        self.assertEqual(ip.dst, "224.0.0.18")
+        self.assertEqual(ip.ttl, 255)
+        self.assertEqual(ip.proto, IPPROTO_VRRP)
+
+        self.assertEqual(vrrp.version, 3)
+        self.assertEqual(vrrp.type, 1)
+        self.assertEqual(vrrp.vrid, vr.vr_id())
+        if prio is None:
+            prio = vr.priority()
+        self.assertEqual(vrrp.priority, prio)
+        self.assertEqual(vrrp.ipcount, len(vips))
+        self.assertEqual(vrrp.adv, vr.adv_interval())
+        self.assertListEqual(vrrp.addrlist, vips)
+
+    # VR with priority 255 owns the virtual address and should
+    # become master and start advertising immediately.
+    def test_vrrp4_master_adv(self):
+        """ IPv4 Master VR advertises """
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        prio = 255
+        intvl = self._default_adv
+        vr = VppVRRPVirtualRouter(self, self.pg0, 100,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags)
+
+        vr.add_vpp_config()
+        vr.start_stop(is_start=1)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+        vr.start_stop(is_start=0)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+
+        pkts = self.pg0.get_capture(4)
+
+        # Init -> Master: IGMP Join, VRRP adv, gratuitous ARP are sent
+        self.verify_vrrp4_igmp(pkts[0])
+        self.verify_vrrp4_adv(pkts[1], vr, prio=prio)
+        self.verify_vrrp4_garp(pkts[2], vr.virtual_ips()[0], vr.virtual_mac())
+        # Master -> Init: Adv with priority 0 sent to force an election
+        self.verify_vrrp4_adv(pkts[3], vr, prio=0)
+
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    # VR with priority < 255 enters backup state and does not advertise as
+    # long as it receives higher priority advertisements
+    def test_vrrp4_backup_noadv(self):
+        """ IPv4 Backup VR does not advertise """
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[self.pg0.remote_ip4])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        vr.start_stop(is_start=1)
+
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        # watch for advertisements for 2x the master down preemption timeout
+        end_time = vr.start_time() + 2 * vr.master_down_seconds()
+
+        # Init -> Backup: An IGMP join should be sent
+        pkts = self.pg0.get_capture(1)
+        self.verify_vrrp4_igmp(pkts[0])
+
+        # send higher prio advertisements, should not receive any
+        src_ip = self.pg0.remote_ip4
+        pkts = [vr.vrrp_adv_packet(prio=prio+10, src_ip=src_ip)]
+        while time.time() < end_time:
+            self.send_and_assert_no_replies(self.pg0, pkts, timeout=intvl_s)
+            self.logger.info(self.vapi.cli("show trace"))
+
+        vr.start_stop(is_start=0)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    def test_vrrp4_master_arp(self):
+        """ IPv4 Master VR replies to ARP """
+        self.pg_start()
+
+        # VR virtual IP is the default, which is the pg local IP
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        vr = VppVRRPVirtualRouter(self, self.pg0, 100,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags)
+        self._vrs.append(vr)
+
+        vr.add_vpp_config()
+
+        # before the VR is up, ARP should resolve to interface MAC
+        self.pg0.resolve_arp()
+        self.assertNotEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        # start the VR, ARP should now resolve to virtual MAC
+        vr.start_stop(is_start=1)
+        self.pg0.resolve_arp()
+        self.assertEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        # stop the VR, ARP should resolve to interface MAC again
+        vr.start_stop(is_start=0)
+        self.pg0.resolve_arp()
+        self.assertNotEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    def test_vrrp4_backup_noarp(self):
+        """ IPv4 Backup VR ignores ARP """
+        # We need an address for a virtual IP that is not the IP that
+        # ARP requests will originate from
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_hosts[1].ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        arp_req = (Ether(dst="ff:ff:ff:ff:ff:ff", src=self.pg0.remote_mac) /
+                   ARP(op=ARP.who_has, pdst=vip,
+                   psrc=self.pg0.remote_ip4, hwsrc=self.pg0.remote_mac))
+
+        # Before the VR is started make sure no reply to request for VIP
+        self.pg_start()
+        self.pg_enable_capture(self.pg_interfaces)
+        self.send_and_assert_no_replies(self.pg0, [arp_req], timeout=1)
+
+        # VR should start in backup state and still should not reply to ARP
+        # send a higher priority adv to make sure it does not become master
+        adv = vr.vrrp_adv_packet(prio=prio+10, src_ip=self.pg0.remote_ip4)
+        vr.start_stop(is_start=1)
+        self.send_and_assert_no_replies(self.pg0, [adv, arp_req], timeout=1)
+
+        vr.start_stop(is_start=0)
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    def test_vrrp4_election(self):
+        """ IPv4 Backup VR becomes master if no advertisements received """
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.remote_ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        self.pg_start()
+        vr.start_stop(is_start=1)
+
+        # VR should be in backup state after starting
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        end_time = vr.start_time() + vr.master_down_seconds()
+
+        # should not receive adverts until timer expires & state transition
+        self.pg_enable_capture(self.pg_interfaces)
+        while (time.time() + intvl_s) < end_time:
+            time.sleep(intvl_s)
+            self.pg0.assert_nothing_captured(filter_out_fn=is_not_adv)
+
+        # VR should be in master state, should send an adv
+        self.pg0.enable_capture()
+        self.pg0.wait_for_packet(intvl_s, is_not_adv)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+    def test_vrrp4_backup_preempts(self):
+        """ IPv4 Backup VR preempts lower priority master """
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.remote_ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        self.pg_start()
+        vr.start_stop(is_start=1)
+
+        # VR should be in backup state after starting
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        end_time = vr.start_time() + vr.master_down_seconds()
+
+        # send lower prio advertisements until timer expires
+        src_ip = self.pg0.remote_ip4
+        pkts = [vr.vrrp_adv_packet(prio=prio-10, src_ip=src_ip)]
+        while time.time() + intvl_s < end_time:
+            self.send_and_assert_no_replies(self.pg0, pkts, timeout=intvl_s)
+            self.logger.info(self.vapi.cli("show trace"))
+
+        # when timer expires, VR should take over as master
+        self.pg0.enable_capture()
+        self.pg0.wait_for_packet(timeout=intvl_s, filter_out_fn=is_not_adv)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+    def test_vrrp4_master_preempted(self):
+        """ IPv4 Master VR preempted by higher priority backup """
+
+        # A prio 255 VR cannot be preempted so the prio has to be lower and
+        # we have to wait for it to take over
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # Build advertisement packet and send it
+        pkts = [vr.vrrp_adv_packet(prio=255, src_ip=self.pg0.remote_ip4)]
+        self.pg_send(self.pg0, pkts)
+
+        # VR should be in backup state again
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+    def test_vrrp4_accept_mode_disabled(self):
+        """ IPv4 Master VR does not reply for VIP w/ accept mode off """
+
+        # accept mode only matters when prio < 255, so it will have to
+        # come up as a backup and take over as master after the timeout
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_hosts[4].ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # send an ICMP echo to the VR virtual IP address
+        echo = (Ether(dst=vr.virtual_mac(), src=self.pg0.remote_mac) /
+                IP(dst=vip, src=self.pg0.remote_ip4) /
+                ICMP(seq=1, id=self.pg0.sw_if_index, type='echo-request'))
+        self.pg_send(self.pg0, [echo])
+
+        # wait for an echo reply. none should be received
+        time.sleep(1)
+        self.pg0.assert_nothing_captured(filter_out_fn=is_not_echo_reply)
+
+    def test_vrrp4_accept_mode_enabled(self):
+        """ IPv4 Master VR replies for VIP w/ accept mode on """
+
+        # A prio 255 VR cannot be preempted so the prio has to be lower and
+        # we have to wait for it to take over
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_hosts[4].ip4
+        flags = (VRRP_VR_FLAG_PREEMPT | VRRP_VR_FLAG_ACCEPT)
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # send an ICMP echo to the VR virtual IP address
+        echo = (Ether(dst=vr.virtual_mac(), src=self.pg0.remote_mac) /
+                IP(dst=vip, src=self.pg0.remote_ip4) /
+                ICMP(seq=1, id=self.pg0.sw_if_index, type='echo-request'))
+        self.pg_send(self.pg0, [echo])
+
+        # wait for an echo reply.
+        time.sleep(1)
+        rx_pkts = self.pg0.get_capture(expected_count=1, timeout=1,
+                                       filter_out_fn=is_not_echo_reply)
+
+        self.assertEqual(rx_pkts[0][IP].src, vip)
+        self.assertEqual(rx_pkts[0][IP].dst, self.pg0.remote_ip4)
+        self.assertEqual(icmptypes[rx_pkts[0][ICMP].type], "echo-reply")
+        self.assertEqual(rx_pkts[0][ICMP].seq, 1)
+        self.assertEqual(rx_pkts[0][ICMP].id, self.pg0.sw_if_index)
+
+    def test_vrrp4_intf_tracking(self):
+        """ IPv4 Master VR adjusts priority based on tracked interface """
+
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.local_ip4
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # add pg1 as a tracked interface and start the VR
+        adjustment = 50
+        adjusted_prio = prio - adjustment
+        vr.add_del_tracked_interface(is_add=1,
+                                     sw_if_index=self.pg1.sw_if_index,
+                                     prio=adjustment)
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        adv_configured = vr.vrrp_adv_packet(prio=prio)
+        adv_adjusted = vr.vrrp_adv_packet(prio=adjusted_prio)
+
+        # tracked intf is up ->  advertised priority == configured priority
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+        # take down pg1, verify priority is now being adjusted
+        self.pg1.admin_down()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_adjusted)
+
+        # bring up pg1, verify priority now matches configured value
+        self.pg1.admin_up()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+        # remove IP address from pg1, verify priority now being adjusted
+        self.pg1.unconfig_ip4()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_adjusted)
+
+        # add IP address to pg1, verify priority now matches configured value
+        self.pg1.config_ip4()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+    def test_vrrp4_master_adv_unicast(self):
+        """ IPv4 Master VR advertises (unicast) """
+
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.local_ip4
+        flags = (self._default_flags | VRRP_VR_FLAG_UNICAST)
+        unicast_peer = self.pg0.remote_hosts[4]
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+        vr.set_unicast_peers([unicast_peer.ip4])
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # Start VR, transition to master
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+
+        self.assertTrue(rx.haslayer(Ether))
+        self.assertTrue(rx.haslayer(IP))
+        self.assertTrue(rx.haslayer(VRRPv3))
+        self.assertEqual(rx[Ether].src, self.pg0.local_mac)
+        self.assertEqual(rx[Ether].dst, unicast_peer.mac)
+        self.assertEqual(rx[IP].src, self.pg0.local_ip4)
+        self.assertEqual(rx[IP].dst, unicast_peer.ip4)
+        self.assertEqual(rx[VRRPv3].vrid, vr_id)
+        self.assertEqual(rx[VRRPv3].priority, prio)
+        self.assertEqual(rx[VRRPv3].ipcount, 1)
+        self.assertEqual(rx[VRRPv3].addrlist, [vip])
+
+
+class TestVRRP6(VppTestCase):
+    """ IPv6 VRRP Test Case """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestVRRP6, cls).setUpClass()
+
+    @classmethod
+    def tearDownClass(cls):
+        super(TestVRRP6, cls).tearDownClass()
+
+    def setUp(self):
+        super(TestVRRP6, self).setUp()
+
+        self.create_pg_interfaces(range(2))
+
+        for i in self.pg_interfaces:
+            i.admin_up()
+            i.config_ip6()
+            i.generate_remote_hosts(5)
+            i.configure_ipv6_neighbors()
+
+        self._vrs = []
+        self._default_flags = (VRRP_VR_FLAG_IPV6 | VRRP_VR_FLAG_PREEMPT)
+        self._default_adv = 100
+
+    def tearDown(self):
+        for vr in self._vrs:
+            try:
+                vr_api = vr.query_vpp_config()
+                if vr_api.runtime.state != VRRP_VR_STATE_INIT:
+                    vr.start_stop(is_start=0)
+                vr.remove_vpp_config()
+            except:
+                self.logger.error("Error cleaning up")
+
+        for i in self.pg_interfaces:
+            i.admin_down()
+            i.unconfig_ip4()
+            i.unconfig_ip6()
+
+        self._vrs = []
+
+        super(TestVRRP6, self).tearDown()
+
+    def verify_vrrp6_mlr(self, pkt, vr):
+        ip6 = pkt[IPv6]
+        self.assertEqual(ip6.dst, "ff02::16")
+        self.assertEqual(ipv6nh[ip6.nh], "Hop-by-Hop Option Header")
+
+        hbh = pkt[IPv6ExtHdrHopByHop]
+        self.assertEqual(ipv6nh[hbh.nh], "ICMPv6")
+
+        self.assertTrue(pkt.haslayer(ICMPv6MLReport2))
+        mlr = pkt[ICMPv6MLReport2]
+        # should contain mc addr records for:
+        # - VRRPv3 multicast addr
+        # - solicited node mc addr record for each VR virtual IPv6 address
+        vips = vr.virtual_ips()
+        self.assertEqual(mlr.records_number, len(vips) + 1)
+        self.assertEqual(mlr.records[0].dst, vr.adv_dest_ip())
+
+    def verify_vrrp6_adv(self, rx_pkt, vr, prio=None):
+        self.assertTrue(rx_pkt.haslayer(Ether))
+        self.assertTrue(rx_pkt.haslayer(IPv6))
+        self.assertTrue(rx_pkt.haslayer(VRRPv3))
+
+        # generate a packet for this VR and compare it to the one received
+        pkt = vr.vrrp_adv_packet(prio=prio)
+        self.assertTrue(rx_pkt.haslayer(Ether))
+        self.assertTrue(rx_pkt.haslayer(IPv6))
+        self.assertTrue(rx_pkt.haslayer(VRRPv3))
+
+        self.assertEqual(pkt, rx_pkt)
+
+    def verify_vrrp6_gna(self, pkt, vr):
+        self.assertTrue(pkt.haslayer(Ether))
+        self.assertTrue(pkt.haslayer(IPv6))
+        self.assertTrue(pkt.haslayer(ICMPv6ND_NA))
+        self.assertTrue(pkt.haslayer(ICMPv6NDOptDstLLAddr))
+
+        self.assertEqual(pkt[Ether].dst, "33:33:00:00:00:01")
+
+        self.assertEqual(pkt[IPv6].dst, "ff02::1")
+        # convert addrs to packed format since string versions could differ
+        src_addr = inet_pton(AF_INET6, pkt[IPv6].src)
+        vr_ll_addr = inet_pton(AF_INET6, vr.interface().local_ip6_ll)
+        self.assertEqual(src_addr, vr_ll_addr)
+
+        self.assertTrue(pkt[ICMPv6ND_NA].tgt in vr.virtual_ips())
+        self.assertEqual(pkt[ICMPv6NDOptDstLLAddr].lladdr, vr.virtual_mac())
+
+    # VR with priority 255 owns the virtual address and should
+    # become master and start advertising immediately.
+    def test_vrrp6_master_adv(self):
+        """ IPv6 Master VR advertises """
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        prio = 255
+        intvl = self._default_adv
+        vr = VppVRRPVirtualRouter(self, self.pg0, 100,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags)
+        self._vrs.append(vr)
+
+        vr.add_vpp_config()
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+        vr.start_stop(is_start=1)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+        vr.start_stop(is_start=0)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+
+        pkts = self.pg0.get_capture(4, filter_out_fn=None)
+
+        # Init -> Master: Multicast group Join, VRRP adv, gratuitous NAs sent
+        self.verify_vrrp6_mlr(pkts[0], vr)
+        self.verify_vrrp6_adv(pkts[1], vr, prio=prio)
+        self.verify_vrrp6_gna(pkts[2], vr)
+        # Master -> Init: Adv with priority 0 sent to force an election
+        self.verify_vrrp6_adv(pkts[3], vr, prio=0)
+
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    # VR with priority < 255 enters backup state and does not advertise as
+    # long as it receives higher priority advertisements
+    def test_vrrp6_backup_noadv(self):
+        """ IPv6 Backup VR does not advertise """
+        self.pg_enable_capture(self.pg_interfaces)
+        self.pg_start()
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[self.pg0.remote_ip6])
+        vr.add_vpp_config()
+        self._vrs.append(vr)
+
+        vr.start_stop(is_start=1)
+
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        # watch for advertisements for 2x the master down preemption timeout
+        end_time = vr.start_time() + 2 * vr.master_down_seconds()
+
+        # Init -> Backup: A multicast listener report should be sent
+        pkts = self.pg0.get_capture(1, filter_out_fn=None)
+
+        # send higher prio advertisements, should not see VPP send any
+        src_ip = self.pg0.remote_ip6_ll
+        num_advs = 5
+        pkts = [vr.vrrp_adv_packet(prio=prio+10, src_ip=src_ip)]
+        self.logger.info(self.vapi.cli("show vlib graph"))
+        while time.time() < end_time:
+            self.send_and_assert_no_replies(self.pg0, pkts, timeout=intvl_s)
+            self.logger.info(self.vapi.cli("show trace"))
+            num_advs -= 1
+
+        vr.start_stop(is_start=0)
+        self.logger.info(self.vapi.cli("show vrrp vr"))
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    def test_vrrp6_master_nd(self):
+        """ IPv6 Master VR replies to NDP """
+        self.pg_start()
+
+        # VR virtual IP is the default, which is the pg local IP
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        vr = VppVRRPVirtualRouter(self, self.pg0, 100,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags)
+        vr.add_vpp_config()
+        self._vrs.append(vr)
+
+        # before the VR is up, NDP should resolve to interface MAC
+        self.pg0.resolve_ndp()
+        self.assertNotEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        # start the VR, NDP should now resolve to virtual MAC
+        vr.start_stop(is_start=1)
+        self.pg0.resolve_ndp()
+        self.assertEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        # stop the VR, ARP should resolve to interface MAC again
+        vr.start_stop(is_start=0)
+        self.pg0.resolve_ndp()
+        self.assertNotEqual(self.pg0.local_mac, vr.virtual_mac())
+
+        vr.remove_vpp_config()
+        self._vrs = []
+
+    def test_vrrp6_backup_nond(self):
+        """ IPv6 Backup VR ignores NDP """
+        # We need an address for a virtual IP that is not the IP that
+        # ARP requests will originate from
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.remote_hosts[1].ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        vr.add_vpp_config()
+        self._vrs.append(vr)
+
+        nsma = in6_getnsma(inet_pton(socket.AF_INET6, vip))
+        dmac = in6_getnsmac(nsma)
+        dst_ip = inet_ntop(socket.AF_INET6, nsma)
+
+        ndp_req = (Ether(dst=dmac, src=self.pg0.remote_mac) /
+                   IPv6(dst=dst_ip, src=self.pg0.remote_ip6) /
+                   ICMPv6ND_NS(tgt=vip) /
+                   ICMPv6NDOptSrcLLAddr(lladdr=self.pg0.remote_mac))
+
+        # Before the VR is started make sure no reply to request for VIP
+        self.send_and_assert_no_replies(self.pg0, [ndp_req], timeout=1)
+
+        # VR should start in backup state and still should not reply to NDP
+        # send a higher priority adv to make sure it does not become master
+        adv = vr.vrrp_adv_packet(prio=prio+10, src_ip=self.pg0.remote_ip6)
+        pkts = [adv, ndp_req]
+        vr.start_stop(is_start=1)
+        self.send_and_assert_no_replies(self.pg0, pkts,  timeout=intvl_s)
+
+        vr.start_stop(is_start=0)
+
+    def test_vrrp6_election(self):
+        """ IPv6 Backup VR becomes master if no advertisements received """
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.remote_ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        self.pg_start()
+        vr.start_stop(is_start=1)
+
+        # VR should be in backup state after starting
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        end_time = vr.start_time() + vr.master_down_seconds()
+
+        # no advertisements should arrive until timer expires
+        self.pg0.enable_capture()
+        while (time.time() + intvl_s) < end_time:
+            time.sleep(intvl_s)
+            self.pg0.assert_nothing_captured(filter_out_fn=is_not_adv)
+
+        # VR should be in master state after timer expires
+        self.pg0.enable_capture()
+        self.pg0.wait_for_packet(intvl_s, is_not_adv)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+    def test_vrrp6_backup_preempts(self):
+        """ IPv6 Backup VR preempts lower priority master """
+
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.remote_ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        self.pg_start()
+        vr.start_stop(is_start=1)
+
+        # VR should be in backup state after starting
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+        end_time = vr.start_time() + vr.master_down_seconds()
+
+        # send lower prio advertisements until timer expires
+        src_ip = self.pg0.remote_ip6
+        pkts = [vr.vrrp_adv_packet(prio=prio-10, src_ip=src_ip)]
+        while (time.time() + intvl_s) < end_time:
+            self.send_and_assert_no_replies(self.pg0, pkts, timeout=intvl_s)
+            self.logger.info(self.vapi.cli("show trace"))
+
+        # when timer expires, VR should take over as master
+        self.pg0.enable_capture()
+        self.pg0.wait_for_packet(timeout=intvl_s, filter_out_fn=is_not_adv)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+    def test_vrrp6_master_preempted(self):
+        """ IPv6 Master VR preempted by higher priority backup """
+
+        # A prio 255 VR cannot be preempted so the prio has to be lower and
+        # we have to wait for it to take over
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # Build advertisement packet and send it
+        pkts = [vr.vrrp_adv_packet(prio=255, src_ip=self.pg0.remote_ip6)]
+        self.pg_send(self.pg0, pkts)
+
+        # VR should be in backup state again
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+    def test_vrrp6_accept_mode_disabled(self):
+        """ IPv6 Master VR does not reply for VIP w/ accept mode off """
+
+        # accept mode only matters when prio < 255, so it will have to
+        # come up as a backup and take over as master after the timeout
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_hosts[4].ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # send an ICMPv6 echo to the VR virtual IP address
+        echo = (Ether(dst=vr.virtual_mac(), src=self.pg0.remote_mac) /
+                IPv6(dst=vip, src=self.pg0.remote_ip6) /
+                ICMPv6EchoRequest(seq=1, id=self.pg0.sw_if_index))
+        self.pg_send(self.pg0, [echo])
+
+        # wait for an echo reply. none should be received
+        time.sleep(1)
+        self.pg0.assert_nothing_captured(filter_out_fn=is_not_echo_reply)
+
+    def test_vrrp6_accept_mode_enabled(self):
+        """ IPv6 Master VR replies for VIP w/ accept mode on """
+
+        # A prio 255 VR cannot be preempted so the prio has to be lower and
+        # we have to wait for it to take over
+        vr_id = 100
+        prio = 100
+        intvl = self._default_adv
+        vip = self.pg0.remote_hosts[4].ip6
+        flags = (self._default_flags | VRRP_VR_FLAG_ACCEPT)
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # start VR
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_BACKUP)
+
+        # wait for VR to take over as master
+        end_time = vr.start_time() + vr.master_down_seconds()
+        sleep_s = end_time - time.time()
+        time.sleep(sleep_s)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        # send an ICMP echo to the VR virtual IP address
+        echo = (Ether(dst=vr.virtual_mac(), src=self.pg0.remote_mac) /
+                IPv6(dst=vip, src=self.pg0.remote_ip6) /
+                ICMPv6EchoRequest(seq=1, id=self.pg0.sw_if_index))
+        self.pg_send(self.pg0, [echo])
+
+        # wait for an echo reply.
+        time.sleep(1)
+        rx_pkts = self.pg0.get_capture(expected_count=1, timeout=1,
+                                       filter_out_fn=is_not_echo_reply)
+
+        self.assertEqual(rx_pkts[0][IPv6].src, vip)
+        self.assertEqual(rx_pkts[0][IPv6].dst, self.pg0.remote_ip6)
+        self.assertEqual(rx_pkts[0][ICMPv6EchoReply].seq, 1)
+        self.assertEqual(rx_pkts[0][ICMPv6EchoReply].id, self.pg0.sw_if_index)
+
+    def test_vrrp6_intf_tracking(self):
+        """ IPv6 Master VR adjusts priority based on tracked interface """
+
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.local_ip6
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=self._default_flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # add pg1 as a tracked interface and start the VR
+        adjustment = 50
+        adjusted_prio = prio - adjustment
+        vr.add_del_tracked_interface(is_add=1,
+                                     sw_if_index=self.pg1.sw_if_index,
+                                     prio=adjustment)
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        adv_configured = vr.vrrp_adv_packet(prio=prio)
+        adv_adjusted = vr.vrrp_adv_packet(prio=adjusted_prio)
+
+        # tracked intf is up ->  advertised priority == configured priority
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+        # take down pg1, verify priority is now being adjusted
+        self.pg1.admin_down()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_adjusted)
+
+        # bring up pg1, verify priority now matches configured value
+        self.pg1.admin_up()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+        # remove IP address from pg1, verify priority now being adjusted
+        self.pg1.unconfig_ip6()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_adjusted)
+
+        # add IP address to pg1, verify priority now matches configured value
+        self.pg1.config_ip6()
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+        self.assertEqual(rx, adv_configured)
+
+    def test_vrrp6_master_adv_unicast(self):
+        """ IPv6 Master VR advertises (unicast) """
+
+        vr_id = 100
+        prio = 255
+        intvl = self._default_adv
+        intvl_s = intvl * 0.01
+        vip = self.pg0.local_ip6
+        flags = (self._default_flags | VRRP_VR_FLAG_UNICAST)
+        unicast_peer = self.pg0.remote_hosts[4]
+        vr = VppVRRPVirtualRouter(self, self.pg0, vr_id,
+                                  prio=prio, intvl=intvl,
+                                  flags=flags,
+                                  vips=[vip])
+        self._vrs.append(vr)
+        vr.add_vpp_config()
+        vr.set_unicast_peers([unicast_peer.ip6])
+
+        # After adding the VR, it should be in the init state
+        vr.assert_state_equals(VRRP_VR_STATE_INIT)
+
+        # Start VR, transition to master
+        vr.start_stop(is_start=1)
+        vr.assert_state_equals(VRRP_VR_STATE_MASTER)
+
+        self.pg0.enable_capture()
+        rx = self.pg0.wait_for_packet(timeout=intvl_s,
+                                      filter_out_fn=is_not_adv)
+
+        self.assertTrue(rx.haslayer(Ether))
+        self.assertTrue(rx.haslayer(IPv6))
+        self.assertTrue(rx.haslayer(VRRPv3))
+        self.assertEqual(rx[Ether].src, self.pg0.local_mac)
+        self.assertEqual(rx[Ether].dst, unicast_peer.mac)
+        self.assertEqual(ip6_normalize(rx[IPv6].src),
+                         ip6_normalize(self.pg0.local_ip6_ll))
+        self.assertEqual(ip6_normalize(rx[IPv6].dst),
+                         ip6_normalize(unicast_peer.ip6))
+        self.assertEqual(rx[VRRPv3].vrid, vr_id)
+        self.assertEqual(rx[VRRPv3].priority, prio)
+        self.assertEqual(rx[VRRPv3].ipcount, 1)
+        self.assertEqual(rx[VRRPv3].addrlist, [vip])
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)