test/test_gre.py

#!/usr/bin/env python

import unittest
from logging import *

from framework import VppTestCase, VppTestRunner
from vpp_sub_interface import VppDot1QSubint
from vpp_gre_interface import VppGreInterface, VppGre6Interface
from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto, VppIpTable
from vpp_papi_provider import L2_VTR_OP

from scapy.packet import Raw
from scapy.layers.l2 import Ether, Dot1Q, GRE
from scapy.layers.inet import IP, UDP
from scapy.layers.inet6 import IPv6
from scapy.volatile import RandMAC, RandIP

from util import ppp, ppc


class TestGRE(VppTestCase):
    """ GRE Test Case """

    @classmethod
    def setUpClass(cls):
        super(TestGRE, cls).setUpClass()

    def setUp(self):
        super(TestGRE, self).setUp()

        # create 3 pg interfaces - set one in a non-default table.
        self.create_pg_interfaces(range(3))

        self.tbl = VppIpTable(self, 1)
        self.tbl.add_vpp_config()
        self.pg1.set_table_ip4(1)

        for i in self.pg_interfaces:
            i.admin_up()

        self.pg0.config_ip4()
        self.pg0.resolve_arp()
        self.pg1.config_ip4()
        self.pg1.resolve_arp()
        self.pg2.config_ip6()
        self.pg2.resolve_ndp()

    def tearDown(self):
        for i in self.pg_interfaces:
            i.unconfig_ip4()
            i.unconfig_ip6()
            i.admin_down()
        self.pg1.set_table_ip4(0)
        super(TestGRE, self).tearDown()

    def create_stream_ip4(self, src_if, src_ip, dst_ip):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IP(src=src_ip, dst=dst_ip) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_stream_ip6(self, src_if, src_ip, dst_ip):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IPv6(src=src_ip, dst=dst_ip) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_tunnel_stream_4o4(self, src_if,
                                 tunnel_src, tunnel_dst,
                                 src_ip, dst_ip):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IP(src=tunnel_src, dst=tunnel_dst) /
                 GRE() /
                 IP(src=src_ip, dst=dst_ip) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_tunnel_stream_6o4(self, src_if,
                                 tunnel_src, tunnel_dst,
                                 src_ip, dst_ip):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IP(src=tunnel_src, dst=tunnel_dst) /
                 GRE() /
                 IPv6(src=src_ip, dst=dst_ip) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_tunnel_stream_6o6(self, src_if,
                                 tunnel_src, tunnel_dst,
                                 src_ip, dst_ip):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IPv6(src=tunnel_src, dst=tunnel_dst) /
                 GRE() /
                 IPv6(src=src_ip, dst=dst_ip) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_tunnel_stream_l2o4(self, src_if,
                                  tunnel_src, tunnel_dst):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IP(src=tunnel_src, dst=tunnel_dst) /
                 GRE() /
                 Ether(dst=RandMAC('*:*:*:*:*:*'),
                       src=RandMAC('*:*:*:*:*:*')) /
                 IP(src=str(RandIP()), dst=str(RandIP())) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def create_tunnel_stream_vlano4(self, src_if,
                                    tunnel_src, tunnel_dst, vlan):
        pkts = []
        for i in range(0, 257):
            info = self.create_packet_info(src_if, src_if)
            payload = self.info_to_payload(info)
            p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
                 IP(src=tunnel_src, dst=tunnel_dst) /
                 GRE() /
                 Ether(dst=RandMAC('*:*:*:*:*:*'),
                       src=RandMAC('*:*:*:*:*:*')) /
                 Dot1Q(vlan=vlan) /
                 IP(src=str(RandIP()), dst=str(RandIP())) /
                 UDP(sport=1234, dport=1234) /
                 Raw(payload))
            info.data = p.copy()
            pkts.append(p)
        return pkts

    def verify_tunneled_4o4(self, src_if, capture, sent,
                            tunnel_src, tunnel_dst):

        self.assertEqual(len(capture), len(sent))

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IP]
                rx_ip = rx[IP]

                self.assertEqual(rx_ip.src, tunnel_src)
                self.assertEqual(rx_ip.dst, tunnel_dst)

                rx_gre = rx[GRE]
                rx_ip = rx_gre[IP]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)
                # IP processing post pop has decremented the TTL
                self.assertEqual(rx_ip.ttl + 1, tx_ip.ttl)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def verify_tunneled_6o6(self, src_if, capture, sent,
                            tunnel_src, tunnel_dst):

        self.assertEqual(len(capture), len(sent))

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IPv6]
                rx_ip = rx[IPv6]

                self.assertEqual(rx_ip.src, tunnel_src)
                self.assertEqual(rx_ip.dst, tunnel_dst)

                rx_gre = GRE(str(rx_ip[IPv6].payload))
                rx_ip = rx_gre[IPv6]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def verify_tunneled_l2o4(self, src_if, capture, sent,
                             tunnel_src, tunnel_dst):
        self.assertEqual(len(capture), len(sent))

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IP]
                rx_ip = rx[IP]

                self.assertEqual(rx_ip.src, tunnel_src)
                self.assertEqual(rx_ip.dst, tunnel_dst)

                rx_gre = rx[GRE]
                rx_l2 = rx_gre[Ether]
                rx_ip = rx_l2[IP]
                tx_gre = tx[GRE]
                tx_l2 = tx_gre[Ether]
                tx_ip = tx_l2[IP]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)
                # bridged, not L3 forwarded, so no TTL decrement
                self.assertEqual(rx_ip.ttl, tx_ip.ttl)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def verify_tunneled_vlano4(self, src_if, capture, sent,
                               tunnel_src, tunnel_dst, vlan):
        try:
            self.assertEqual(len(capture), len(sent))
        except:
            ppc("Unexpected packets captured:", capture)
            raise

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IP]
                rx_ip = rx[IP]

                self.assertEqual(rx_ip.src, tunnel_src)
                self.assertEqual(rx_ip.dst, tunnel_dst)

                rx_gre = rx[GRE]
                rx_l2 = rx_gre[Ether]
                rx_vlan = rx_l2[Dot1Q]
                rx_ip = rx_l2[IP]

                self.assertEqual(rx_vlan.vlan, vlan)

                tx_gre = tx[GRE]
                tx_l2 = tx_gre[Ether]
                tx_ip = tx_l2[IP]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)
                # bridged, not L3 forwarded, so no TTL decrement
                self.assertEqual(rx_ip.ttl, tx_ip.ttl)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def verify_decapped_4o4(self, src_if, capture, sent):
        self.assertEqual(len(capture), len(sent))

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IP]
                rx_ip = rx[IP]
                tx_gre = tx[GRE]
                tx_ip = tx_gre[IP]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)
                # IP processing post pop has decremented the TTL
                self.assertEqual(rx_ip.ttl + 1, tx_ip.ttl)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def verify_decapped_6o4(self, src_if, capture, sent):
        self.assertEqual(len(capture), len(sent))

        for i in range(len(capture)):
            try:
                tx = sent[i]
                rx = capture[i]

                tx_ip = tx[IP]
                rx_ip = rx[IPv6]
                tx_gre = tx[GRE]
                tx_ip = tx_gre[IPv6]

                self.assertEqual(rx_ip.src, tx_ip.src)
                self.assertEqual(rx_ip.dst, tx_ip.dst)
                self.assertEqual(rx_ip.hlim + 1, tx_ip.hlim)

            except:
                self.logger.error(ppp("Rx:", rx))
                self.logger.error(ppp("Tx:", tx))
                raise

    def test_gre(self):
        """ GRE IPv4 tunnel Tests """

        #
        # Create an L3 GRE tunnel.
        #  - set it admin up
        #  - assign an IP Addres
        #  - Add a route via the tunnel
        #
        gre_if = VppGreInterface(self,
                                 self.pg0.local_ip4,
                                 "1.1.1.2")
        gre_if.add_vpp_config()

        #
        # The double create (create the same tunnel twice) should fail,
        # and we should still be able to use the original
        #
        try:
            gre_if.add_vpp_config()
        except Exception:
            pass
        else:
            self.fail("Double GRE tunnel add does not fail")

        gre_if.admin_up()
        gre_if.config_ip4()

        route_via_tun = VppIpRoute(self, "4.4.4.4", 32,
                                   [VppRoutePath("0.0.0.0",
                                                 gre_if.sw_if_index)])

        route_via_tun.add_vpp_config()

        #
        # Send a packet stream that is routed into the tunnel
        #  - they are all dropped since the tunnel's desintation IP
        #    is unresolved - or resolves via the default route - which
        #    which is a drop.
        #
        tx = self.create_stream_ip4(self.pg0, "5.5.5.5", "4.4.4.4")
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        self.pg0.assert_nothing_captured(
            remark="GRE packets forwarded without DIP resolved")

        #
        # Add a route that resolves the tunnel's destination
        #
        route_tun_dst = VppIpRoute(self, "1.1.1.2", 32,
                                   [VppRoutePath(self.pg0.remote_ip4,
                                                 self.pg0.sw_if_index)])
        route_tun_dst.add_vpp_config()

        #
        # Send a packet stream that is routed into the tunnel
        #  - packets are GRE encapped
        #
        self.vapi.cli("clear trace")
        tx = self.create_stream_ip4(self.pg0, "5.5.5.5", "4.4.4.4")
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_tunneled_4o4(self.pg0, rx, tx,
                                 self.pg0.local_ip4, "1.1.1.2")

        #
        # Send tunneled packets that match the created tunnel and
        # are decapped and forwarded
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_4o4(self.pg0,
                                           "1.1.1.2",
                                           self.pg0.local_ip4,
                                           self.pg0.local_ip4,
                                           self.pg0.remote_ip4)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_decapped_4o4(self.pg0, rx, tx)

        #
        # Send tunneled packets that do not match the tunnel's src
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_4o4(self.pg0,
                                           "1.1.1.3",
                                           self.pg0.local_ip4,
                                           self.pg0.local_ip4,
                                           self.pg0.remote_ip4)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        self.pg0.assert_nothing_captured(
            remark="GRE packets forwarded despite no SRC address match")

        #
        # Configure IPv6 on the PG interface so we can route IPv6
        # packets
        #
        self.pg0.config_ip6()
        self.pg0.resolve_ndp()

        #
        # Send IPv6 tunnel encapslated packets
        #  - dropped since IPv6 is not enabled on the tunnel
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_6o4(self.pg0,
                                           "1.1.1.2",
                                           self.pg0.local_ip4,
                                           self.pg0.local_ip6,
                                           self.pg0.remote_ip6)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        self.pg0.assert_nothing_captured(remark="IPv6 GRE packets forwarded "
                                         "despite IPv6 not enabled on tunnel")

        #
        # Enable IPv6 on the tunnel
        #
        gre_if.config_ip6()

        #
        # Send IPv6 tunnel encapslated packets
        #  - forwarded since IPv6 is enabled on the tunnel
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_6o4(self.pg0,
                                           "1.1.1.2",
                                           self.pg0.local_ip4,
                                           self.pg0.local_ip6,
                                           self.pg0.remote_ip6)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_decapped_6o4(self.pg0, rx, tx)

        #
        # test case cleanup
        #
        route_tun_dst.remove_vpp_config()
        route_via_tun.remove_vpp_config()
        gre_if.remove_vpp_config()

        self.pg0.unconfig_ip6()

    def test_gre6(self):
        """ GRE IPv6 tunnel Tests """

        #
        # Create an L3 GRE tunnel.
        #  - set it admin up
        #  - assign an IP Address
        #  - Add a route via the tunnel
        #
        gre_if = VppGre6Interface(self,
                                  self.pg2.local_ip6,
                                  "1002::1")
        gre_if.add_vpp_config()
        gre_if.admin_up()
        gre_if.config_ip6()

        route_via_tun = VppIpRoute(
            self, "4004::1", 128,
            [VppRoutePath("0::0",
                          gre_if.sw_if_index,
                          proto=DpoProto.DPO_PROTO_IP6)],
            is_ip6=1)

        route_via_tun.add_vpp_config()

        #
        # Send a packet stream that is routed into the tunnel
        #  - they are all dropped since the tunnel's desintation IP
        #    is unresolved - or resolves via the default route - which
        #    which is a drop.
        #
        tx = self.create_stream_ip6(self.pg2, "5005::1", "4004::1")
        self.pg2.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        self.pg2.assert_nothing_captured(
            remark="GRE packets forwarded without DIP resolved")

        #
        # Add a route that resolves the tunnel's destination
        #
        route_tun_dst = VppIpRoute(
            self, "1002::1", 128,
            [VppRoutePath(self.pg2.remote_ip6,
                          self.pg2.sw_if_index,
                          proto=DpoProto.DPO_PROTO_IP6)],
            is_ip6=1)
        route_tun_dst.add_vpp_config()

        #
        # Send a packet stream that is routed into the tunnel
        #  - packets are GRE encapped
        #
        self.vapi.cli("clear trace")
        tx = self.create_stream_ip6(self.pg2, "5005::1", "4004::1")
        self.pg2.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg2.get_capture(len(tx))
        self.verify_tunneled_6o6(self.pg2, rx, tx,
                                 self.pg2.local_ip6, "1002::1")

        #
        # test case cleanup
        #
        route_tun_dst.remove_vpp_config()
        route_via_tun.remove_vpp_config()
        gre_if.remove_vpp_config()

        self.pg2.unconfig_ip6()

    def test_gre_vrf(self):
        """ GRE tunnel VRF Tests """

        #
        # Create an L3 GRE tunnel whose destination is in the non-default
        # table. The underlay is thus non-default - the overlay is still
        # the default.
        #  - set it admin up
        #  - assign an IP Addres
        #
        gre_if = VppGreInterface(self, self.pg1.local_ip4,
                                 "2.2.2.2",
                                 outer_fib_id=1)
        gre_if.add_vpp_config()
        gre_if.admin_up()
        gre_if.config_ip4()

        #
        # Add a route via the tunnel - in the overlay
        #
        route_via_tun = VppIpRoute(self, "9.9.9.9", 32,
                                   [VppRoutePath("0.0.0.0",
                                                 gre_if.sw_if_index)])
        route_via_tun.add_vpp_config()

        #
        # Add a route that resolves the tunnel's destination - in the
        # underlay table
        #
        route_tun_dst = VppIpRoute(self, "2.2.2.2", 32, table_id=1,
                                   paths=[VppRoutePath(self.pg1.remote_ip4,
                                                       self.pg1.sw_if_index)])
        route_tun_dst.add_vpp_config()

        #
        # Send a packet stream that is routed into the tunnel
        # packets are sent in on pg0 which is in the default table
        #  - packets are GRE encapped
        #
        self.vapi.cli("clear trace")
        tx = self.create_stream_ip4(self.pg0, "5.5.5.5", "9.9.9.9")
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg1.get_capture(len(tx))
        self.verify_tunneled_4o4(self.pg1, rx, tx,
                                 self.pg1.local_ip4, "2.2.2.2")

        #
        # Send tunneled packets that match the created tunnel and
        # are decapped and forwarded. This tests the decap lookup
        # does not happen in the encap table
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_4o4(self.pg1,
                                           "2.2.2.2",
                                           self.pg1.local_ip4,
                                           self.pg0.local_ip4,
                                           self.pg0.remote_ip4)
        self.pg1.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_decapped_4o4(self.pg0, rx, tx)

        #
        # test case cleanup
        #
        route_tun_dst.remove_vpp_config()
        route_via_tun.remove_vpp_config()
        gre_if.remove_vpp_config()

    def test_gre_l2(self):
        """ GRE tunnel L2 Tests """

        #
        # Add routes to resolve the tunnel destinations
        #
        route_tun1_dst = VppIpRoute(self, "2.2.2.2", 32,
                                    [VppRoutePath(self.pg0.remote_ip4,
                                                  self.pg0.sw_if_index)])
        route_tun2_dst = VppIpRoute(self, "2.2.2.3", 32,
                                    [VppRoutePath(self.pg0.remote_ip4,
                                                  self.pg0.sw_if_index)])

        route_tun1_dst.add_vpp_config()
        route_tun2_dst.add_vpp_config()

        #
        # Create 2 L2 GRE tunnels and x-connect them
        #
        gre_if1 = VppGreInterface(self, self.pg0.local_ip4,
                                  "2.2.2.2",
                                  is_teb=1)
        gre_if2 = VppGreInterface(self, self.pg0.local_ip4,
                                  "2.2.2.3",
                                  is_teb=1)
        gre_if1.add_vpp_config()
        gre_if2.add_vpp_config()

        gre_if1.admin_up()
        gre_if2.admin_up()

        self.vapi.sw_interface_set_l2_xconnect(gre_if1.sw_if_index,
                                               gre_if2.sw_if_index,
                                               enable=1)
        self.vapi.sw_interface_set_l2_xconnect(gre_if2.sw_if_index,
                                               gre_if1.sw_if_index,
                                               enable=1)

        #
        # Send in tunnel encapped L2. expect out tunnel encapped L2
        # in both directions
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_l2o4(self.pg0,
                                            "2.2.2.2",
                                            self.pg0.local_ip4)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_tunneled_l2o4(self.pg0, rx, tx,
                                  self.pg0.local_ip4,
                                  "2.2.2.3")

        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_l2o4(self.pg0,
                                            "2.2.2.3",
                                            self.pg0.local_ip4)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_tunneled_l2o4(self.pg0, rx, tx,
                                  self.pg0.local_ip4,
                                  "2.2.2.2")

        self.vapi.sw_interface_set_l2_xconnect(gre_if1.sw_if_index,
                                               gre_if2.sw_if_index,
                                               enable=0)
        self.vapi.sw_interface_set_l2_xconnect(gre_if2.sw_if_index,
                                               gre_if1.sw_if_index,
                                               enable=0)

        #
        # Create a VLAN sub-interfaces on the GRE TEB interfaces
        # then x-connect them
        #
        gre_if_11 = VppDot1QSubint(self, gre_if1, 11)
        gre_if_12 = VppDot1QSubint(self, gre_if2, 12)

        # gre_if_11.add_vpp_config()
        # gre_if_12.add_vpp_config()

        gre_if_11.admin_up()
        gre_if_12.admin_up()

        self.vapi.sw_interface_set_l2_xconnect(gre_if_11.sw_if_index,
                                               gre_if_12.sw_if_index,
                                               enable=1)
        self.vapi.sw_interface_set_l2_xconnect(gre_if_12.sw_if_index,
                                               gre_if_11.sw_if_index,
                                               enable=1)

        #
        # Configure both to pop thier respective VLAN tags,
        # so that during the x-coonect they will subsequently push
        #
        self.vapi.sw_interface_set_l2_tag_rewrite(gre_if_12.sw_if_index,
                                                  L2_VTR_OP.L2_POP_1,
                                                  12)
        self.vapi.sw_interface_set_l2_tag_rewrite(gre_if_11.sw_if_index,
                                                  L2_VTR_OP.L2_POP_1,
                                                  11)

        #
        # Send traffic in both directiond - expect the VLAN tags to
        # be swapped.
        #
        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_vlano4(self.pg0,
                                              "2.2.2.2",
                                              self.pg0.local_ip4,
                                              11)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_tunneled_vlano4(self.pg0, rx, tx,
                                    self.pg0.local_ip4,
                                    "2.2.2.3",
                                    12)

        self.vapi.cli("clear trace")
        tx = self.create_tunnel_stream_vlano4(self.pg0,
                                              "2.2.2.3",
                                              self.pg0.local_ip4,
                                              12)
        self.pg0.add_stream(tx)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        rx = self.pg0.get_capture(len(tx))
        self.verify_tunneled_vlano4(self.pg0, rx, tx,
                                    self.pg0.local_ip4,
                                    "2.2.2.2",
                                    11)

        #
        # Cleanup Test resources
        #
        gre_if_11.remove_vpp_config()
        gre_if_12.remove_vpp_config()
        gre_if1.remove_vpp_config()
        gre_if2.remove_vpp_config()
        route_tun1_dst.add_vpp_config()
        route_tun2_dst.add_vpp_config()


if __name__ == '__main__':
    unittest.main(testRunner=VppTestRunner)