srv6-as: Adding test cases

Change-Id: I597a88d255c2f7cff552b1fa12ed4a7c4579b91c
Signed-off-by: Francois Clad <fclad@cisco.com>

1 files changed, 692 insertions, 0 deletions

diff --git a/test/test_srv6_as.py b/test/test_srv6_as.py
new file mode 100644
index 00000000000..0e94bd97ce6
--- /dev/null
+++ b/test/test_srv6_as.py
@@ -0,0 +1,692 @@
+#!/usr/bin/env python
+
+import unittest
+import binascii
+from socket import AF_INET6
+
+from framework import VppTestCase, VppTestRunner
+from vpp_ip_route import VppIpRoute, VppRoutePath, DpoProto, VppIpTable
+from vpp_srv6 import SRv6LocalSIDBehaviors, VppSRv6LocalSID, VppSRv6Policy, \
+    SRv6PolicyType, VppSRv6Steering, SRv6PolicySteeringTypes
+
+from scapy.packet import Raw
+from scapy.layers.l2 import Ether, Dot1Q
+from scapy.layers.inet6 import IPv6, UDP, IPv6ExtHdrSegmentRouting
+from scapy.layers.inet import IP, UDP
+
+from scapy.utils import inet_pton, inet_ntop
+
+from util import ppp
+
+
+class TestSRv6(VppTestCase):
+    """ SRv6 Static Proxy plugin Test Case """
+
+    @classmethod
+    def setUpClass(self):
+        super(TestSRv6, self).setUpClass()
+
+    def setUp(self):
+        """ Perform test setup before each test case.
+        """
+        super(TestSRv6, self).setUp()
+
+        # packet sizes, inclusive L2 overhead
+        self.pg_packet_sizes = [64, 512, 1518, 9018]
+
+        # reset packet_infos
+        self.reset_packet_infos()
+
+    def tearDown(self):
+        """ Clean up test setup after each test case.
+        """
+        self.teardown_interfaces()
+
+        super(TestSRv6, self).tearDown()
+
+    def configure_interface(self,
+                            interface,
+                            ipv6=False, ipv4=False,
+                            ipv6_table_id=0, ipv4_table_id=0):
+        """ Configure interface.
+        :param ipv6: configure IPv6 on interface
+        :param ipv4: configure IPv4 on interface
+        :param ipv6_table_id: FIB table_id for IPv6
+        :param ipv4_table_id: FIB table_id for IPv4
+        """
+        self.logger.debug("Configuring interface %s" % (interface.name))
+        if ipv6:
+            self.logger.debug("Configuring IPv6")
+            interface.set_table_ip6(ipv6_table_id)
+            interface.config_ip6()
+            interface.resolve_ndp(timeout=5)
+        if ipv4:
+            self.logger.debug("Configuring IPv4")
+            interface.set_table_ip4(ipv4_table_id)
+            interface.config_ip4()
+            interface.resolve_arp()
+        interface.admin_up()
+
+    def setup_interfaces(self, ipv6=[], ipv4=[],
+                         ipv6_table_id=[], ipv4_table_id=[]):
+        """ Create and configure interfaces.
+
+        :param ipv6: list of interface IPv6 capabilities
+        :param ipv4: list of interface IPv4 capabilities
+        :param ipv6_table_id: list of intf IPv6 FIB table_ids
+        :param ipv4_table_id: list of intf IPv4 FIB table_ids
+        :returns: List of created interfaces.
+        """
+        # how many interfaces?
+        if len(ipv6):
+            count = len(ipv6)
+        else:
+            count = len(ipv4)
+        self.logger.debug("Creating and configuring %d interfaces" % (count))
+
+        # fill up ipv6 and ipv4 lists if needed
+        # not enabled (False) is the default
+        if len(ipv6) < count:
+            ipv6 += (count - len(ipv6)) * [False]
+        if len(ipv4) < count:
+            ipv4 += (count - len(ipv4)) * [False]
+
+        # fill up table_id lists if needed
+        # table_id 0 (global) is the default
+        if len(ipv6_table_id) < count:
+            ipv6_table_id += (count - len(ipv6_table_id)) * [0]
+        if len(ipv4_table_id) < count:
+            ipv4_table_id += (count - len(ipv4_table_id)) * [0]
+
+        # create 'count' pg interfaces
+        self.create_pg_interfaces(range(count))
+
+        # setup all interfaces
+        for i in range(count):
+            intf = self.pg_interfaces[i]
+            self.configure_interface(intf,
+                                     ipv6[i], ipv4[i],
+                                     ipv6_table_id[i], ipv4_table_id[i])
+
+        if any(ipv6):
+            self.logger.debug(self.vapi.cli("show ip6 neighbors"))
+        if any(ipv4):
+            self.logger.debug(self.vapi.cli("show ip arp"))
+        self.logger.debug(self.vapi.cli("show interface"))
+        self.logger.debug(self.vapi.cli("show hardware"))
+
+        return self.pg_interfaces
+
+    def teardown_interfaces(self):
+        """ Unconfigure and bring down interface.
+        """
+        self.logger.debug("Tearing down interfaces")
+        # tear down all interfaces
+        # AFAIK they cannot be deleted
+        for i in self.pg_interfaces:
+            self.logger.debug("Tear down interface %s" % (i.name))
+            i.admin_down()
+            i.unconfig()
+            i.set_table_ip4(0)
+            i.set_table_ip6(0)
+
+    def test_SRv6_End_AS_IPv6_noSRH(self):
+        """ Test SRv6 End.AS behavior with IPv6 traffic and no SRH rewrite.
+        """
+        self.run_SRv6_End_AS_IPv6(
+            sid_list=['a1::', 'a2::a6', 'a3::'],
+            test_sid_index=1,
+            rewrite_src_addr='a2::')
+
+    def test_SRv6_End_AS_IPv6_SRH(self):
+        """ Test SRv6 End.AS behavior with IPv6 traffic and SRH rewrite.
+        """
+        self.run_SRv6_End_AS_IPv6(
+            sid_list=['a1::a6', 'a2::', 'a3::'],
+            test_sid_index=0,
+            rewrite_src_addr='a1::')
+
+    def test_SRv6_End_AS_IPv4_noSRH(self):
+        """ Test SRv6 End.AS behavior with IPv4 traffic and no SRH rewrite.
+        """
+        self.run_SRv6_End_AS_IPv4(
+            sid_list=['a1::', 'a2::a6', 'a3::'],
+            test_sid_index=1,
+            rewrite_src_addr='a2::')
+
+    def test_SRv6_End_AS_IPv4_SRH(self):
+        """ Test SRv6 End.AS behavior with IPv4 traffic and SRH rewrite.
+        """
+        self.run_SRv6_End_AS_IPv4(
+            sid_list=['a1::a6', 'a2::', 'a3::'],
+            test_sid_index=0,
+            rewrite_src_addr='a1::')
+
+    def run_SRv6_End_AS_IPv6(self, sid_list, test_sid_index, rewrite_src_addr):
+        """ Run SRv6 End.AS test with IPv6 traffic.
+        """
+        self.rewrite_src_addr = rewrite_src_addr
+        self.rewrite_sid_list = sid_list[test_sid_index + 1::]
+
+        # send traffic to one destination interface
+        # source and destination interfaces are IPv6 only
+        self.setup_interfaces(ipv6=[True, True])
+
+        # configure route to next segment
+        route = VppIpRoute(self, sid_list[test_sid_index + 1], 128,
+                           [VppRoutePath(self.pg0.remote_ip6,
+                                         self.pg0.sw_if_index,
+                                         proto=DpoProto.DPO_PROTO_IP6)],
+                           is_ip6=1)
+        route.add_vpp_config()
+
+        # configure SRv6 localSID behavior
+        cli_str = "sr localsid address " + sid_list[test_sid_index] \
+            + " behavior end.as" \
+            + " nh " + self.pg1.remote_ip6 \
+            + " oif " + self.pg1.name \
+            + " iif " + self.pg1.name \
+            + " src " + self.rewrite_src_addr
+        for s in self.rewrite_sid_list:
+            cli_str += " next " + s
+        self.vapi.cli(cli_str)
+
+        # log the localsids
+        self.logger.debug(self.vapi.cli("show sr localsid"))
+
+        # send one packet per packet size
+        count = len(self.pg_packet_sizes)
+
+        # prepare IPv6 in SRv6 headers
+        packet_header1 = self.create_packet_header_IPv6_SRH_IPv6(
+                        sidlist=sid_list[::-1],
+                        segleft=len(sid_list) - test_sid_index - 1)
+
+        # generate packets (pg0->pg1)
+        pkts1 = self.create_stream(self.pg0, self.pg1, packet_header1,
+                                   self.pg_packet_sizes, count)
+
+        # send packets and verify received packets
+        self.send_and_verify_pkts(self.pg0, pkts1, self.pg1,
+                                  self.compare_rx_tx_packet_End_AS_IPv6_out)
+
+        # log the localsid counters
+        self.logger.info(self.vapi.cli("show sr localsid"))
+
+        # prepare IPv6 header for returning packets
+        packet_header2 = self.create_packet_header_IPv6()
+
+        # generate returning packets (pg1->pg0)
+        pkts2 = self.create_stream(self.pg1, self.pg0, packet_header2,
+                                   self.pg_packet_sizes, count)
+
+        # send packets and verify received packets
+        self.send_and_verify_pkts(self.pg1, pkts2, self.pg0,
+                                  self.compare_rx_tx_packet_End_AS_IPv6_in)
+
+        # log the localsid counters
+        self.logger.info(self.vapi.cli("show sr localsid"))
+
+        # remove SRv6 localSIDs
+        self.vapi.cli("sr localsid del address " + sid_list[test_sid_index])
+
+        # cleanup interfaces
+        self.teardown_interfaces()
+
+    def run_SRv6_End_AS_IPv4(self, sid_list, test_sid_index, rewrite_src_addr):
+        """ Run SRv6 End.AS test with IPv4 traffic.
+        """
+        self.rewrite_src_addr = rewrite_src_addr
+        self.rewrite_sid_list = sid_list[test_sid_index + 1::]
+
+        # send traffic to one destination interface
+        # source and destination interfaces are IPv6 only
+        self.setup_interfaces(ipv6=[True, False], ipv4=[True, True])
+
+        # configure route to next segment
+        route = VppIpRoute(self, sid_list[test_sid_index + 1], 128,
+                           [VppRoutePath(self.pg0.remote_ip6,
+                                         self.pg0.sw_if_index,
+                                         proto=DpoProto.DPO_PROTO_IP6)],
+                           is_ip6=1)
+        route.add_vpp_config()
+
+        # configure SRv6 localSID behavior
+        cli_str = "sr localsid address " + sid_list[test_sid_index] \
+            + " behavior end.as" \
+            + " nh " + self.pg1.remote_ip4 \
+            + " oif " + self.pg1.name \
+            + " iif " + self.pg1.name \
+            + " src " + self.rewrite_src_addr
+        for s in self.rewrite_sid_list:
+            cli_str += " next " + s
+        self.vapi.cli(cli_str)
+
+        # log the localsids
+        self.logger.debug(self.vapi.cli("show sr localsid"))
+
+        # send one packet per packet size
+        count = len(self.pg_packet_sizes)
+
+        # prepare IPv4 in SRv6 headers
+        packet_header1 = self.create_packet_header_IPv6_SRH_IPv4(
+                        sidlist=sid_list[::-1],
+                        segleft=len(sid_list) - test_sid_index - 1)
+
+        # generate packets (pg0->pg1)
+        pkts1 = self.create_stream(self.pg0, self.pg1, packet_header1,
+                                   self.pg_packet_sizes, count)
+
+        # send packets and verify received packets
+        self.send_and_verify_pkts(self.pg0, pkts1, self.pg1,
+                                  self.compare_rx_tx_packet_End_AS_IPv4_out)
+
+        # log the localsid counters
+        self.logger.info(self.vapi.cli("show sr localsid"))
+
+        # prepare IPv6 header for returning packets
+        packet_header2 = self.create_packet_header_IPv4()
+
+        # generate returning packets (pg1->pg0)
+        pkts2 = self.create_stream(self.pg1, self.pg0, packet_header2,
+                                   self.pg_packet_sizes, count)
+
+        # send packets and verify received packets
+        self.send_and_verify_pkts(self.pg1, pkts2, self.pg0,
+                                  self.compare_rx_tx_packet_End_AS_IPv4_in)
+
+        # log the localsid counters
+        self.logger.info(self.vapi.cli("show sr localsid"))
+
+        # remove SRv6 localSIDs
+        self.vapi.cli("sr localsid del address " + sid_list[test_sid_index])
+
+        # cleanup interfaces
+        self.teardown_interfaces()
+
+    def compare_rx_tx_packet_End_AS_IPv6_in(self, tx_pkt, rx_pkt):
+        """ Compare input and output packet after passing End.AS
+
+        :param tx_pkt: transmitted packet
+        :param rx_pkt: received packet
+        """
+
+        # get first (outer) IPv6 header of rx'ed packet
+        rx_ip = rx_pkt.getlayer(IPv6)
+        rx_srh = None
+
+        tx_ip = tx_pkt.getlayer(IPv6)
+
+        # expected segment-list (SRH order)
+        tx_seglist = self.rewrite_sid_list[::-1]
+
+        # received ip.src should be equal to SR Policy source
+        self.assertEqual(rx_ip.src, self.rewrite_src_addr)
+        # received ip.dst should be equal to expected sidlist[lastentry]
+        self.assertEqual(rx_ip.dst, tx_seglist[-1])
+
+        if len(tx_seglist) > 1:
+            # rx'ed packet should have SRH
+            self.assertTrue(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+            # get SRH
+            rx_srh = rx_pkt.getlayer(IPv6ExtHdrSegmentRouting)
+            # rx'ed seglist should be equal to expected seglist
+            self.assertEqual(rx_srh.addresses, tx_seglist)
+            # segleft should be equal to size expected seglist-1
+            self.assertEqual(rx_srh.segleft, len(tx_seglist)-1)
+            # segleft should be equal to lastentry
+            self.assertEqual(rx_srh.segleft, rx_srh.lastentry)
+            # get payload
+            payload = rx_srh.payload
+        else:
+            # rx'ed packet should NOT have SRH
+            self.assertFalse(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+            # get payload
+            payload = rx_ip.payload
+
+        # the whole rx'ed pkt beyond SRH should be equal to tx'ed pkt
+        # except for the hop-limit field
+        #   -> update tx'ed hlim to the expected hlim
+        tx_ip.hlim = tx_ip.hlim - 1
+
+        self.assertEqual(payload, tx_ip)
+
+        self.logger.debug("packet verification: SUCCESS")
+
+    def compare_rx_tx_packet_End_AS_IPv4_in(self, tx_pkt, rx_pkt):
+        """ Compare input and output packet after passing End.AS
+
+        :param tx_pkt: transmitted packet
+        :param rx_pkt: received packet
+        """
+
+        # get first (outer) IPv6 header of rx'ed packet
+        rx_ip = rx_pkt.getlayer(IPv6)
+        rx_srh = None
+
+        tx_ip = tx_pkt.getlayer(IP)
+
+        # expected segment-list (SRH order)
+        tx_seglist = self.rewrite_sid_list[::-1]
+
+        # received ip.src should be equal to SR Policy source
+        self.assertEqual(rx_ip.src, self.rewrite_src_addr)
+        # received ip.dst should be equal to expected sidlist[lastentry]
+        self.assertEqual(rx_ip.dst, tx_seglist[-1])
+
+        if len(tx_seglist) > 1:
+            # rx'ed packet should have SRH and IPv4 header
+            self.assertTrue(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+            self.assertTrue(rx_ip.payload.haslayer(IP))
+            # get SRH
+            rx_srh = rx_pkt.getlayer(IPv6ExtHdrSegmentRouting)
+            # rx'ed seglist should be equal to seglist
+            self.assertEqual(rx_srh.addresses, tx_seglist)
+            # segleft should be equal to size seglist-1
+            self.assertEqual(rx_srh.segleft, len(tx_seglist)-1)
+            # segleft should be equal to lastentry
+            self.assertEqual(rx_srh.segleft, rx_srh.lastentry)
+            payload = rx_srh.payload
+        else:
+            # rx'ed packet should NOT have SRH
+            self.assertFalse(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+            # get payload
+            payload = rx_ip.payload
+
+        # the whole rx'ed pkt beyond SRH should be equal to tx'ed pkt
+        # except for the ttl field and ip checksum
+        #   -> adjust tx'ed ttl to expected ttl
+        tx_ip.ttl = tx_ip.ttl - 1
+        #   -> set tx'ed ip checksum to None and let scapy recompute
+        tx_ip.chksum = None
+        # read back the pkt (with str()) to force computing these fields
+        # probably other ways to accomplish this are possible
+        tx_ip = IP(str(tx_ip))
+
+        self.assertEqual(payload, tx_ip)
+
+        self.logger.debug("packet verification: SUCCESS")
+
+    def compare_rx_tx_packet_End_AS_IPv6_out(self, tx_pkt, rx_pkt):
+        """ Compare input and output packet after passing End.AS with IPv6
+
+        :param tx_pkt: transmitted packet
+        :param rx_pkt: received packet
+        """
+
+        # get first (outer) IPv6 header of rx'ed packet
+        rx_ip = rx_pkt.getlayer(IPv6)
+
+        tx_ip = tx_pkt.getlayer(IPv6)
+        tx_ip2 = tx_pkt.getlayer(IPv6, 2)
+
+        # verify if rx'ed packet has no SRH
+        self.assertFalse(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+
+        # the whole rx_ip pkt should be equal to tx_ip2
+        # except for the hlim field
+        #   -> adjust tx'ed hlim to expected hlim
+        tx_ip2.hlim = tx_ip2.hlim - 1
+
+        self.assertEqual(rx_ip, tx_ip2)
+
+        self.logger.debug("packet verification: SUCCESS")
+
+    def compare_rx_tx_packet_End_AS_IPv4_out(self, tx_pkt, rx_pkt):
+        """ Compare input and output packet after passing End.AS with IPv4
+
+        :param tx_pkt: transmitted packet
+        :param rx_pkt: received packet
+        """
+
+        # get IPv4 header of rx'ed packet
+        rx_ip = rx_pkt.getlayer(IP)
+
+        tx_ip = tx_pkt.getlayer(IPv6)
+        tx_ip2 = tx_pkt.getlayer(IP)
+
+        # verify if rx'ed packet has no SRH
+        self.assertFalse(rx_pkt.haslayer(IPv6ExtHdrSegmentRouting))
+
+        # the whole rx_ip pkt should be equal to tx_ip2
+        # except for the ttl field and ip checksum
+        #   -> adjust tx'ed ttl to expected ttl
+        tx_ip2.ttl = tx_ip2.ttl - 1
+        #   -> set tx'ed ip checksum to None and let scapy recompute
+        tx_ip2.chksum = None
+        # read back the pkt (with str()) to force computing these fields
+        # probably other ways to accomplish this are possible
+        tx_ip2 = IP(str(tx_ip2))
+
+        self.assertEqual(rx_ip, tx_ip2)
+
+        self.logger.debug("packet verification: SUCCESS")
+
+    def create_stream(self, src_if, dst_if, packet_header, packet_sizes,
+                      count):
+        """Create SRv6 input packet stream for defined interface.
+
+        :param VppInterface src_if: Interface to create packet stream for
+        :param VppInterface dst_if: destination interface of packet stream
+        :param packet_header: Layer3 scapy packet headers,
+                L2 is added when not provided,
+                Raw(payload) with packet_info is added
+        :param list packet_sizes: packet stream pckt sizes,sequentially applied
+               to packets in stream have
+        :param int count: number of packets in packet stream
+        :return: list of packets
+        """
+        self.logger.info("Creating packets")
+        pkts = []
+        for i in range(0, count-1):
+            payload_info = self.create_packet_info(src_if, dst_if)
+            self.logger.debug(
+                "Creating packet with index %d" % (payload_info.index))
+            payload = self.info_to_payload(payload_info)
+            # add L2 header if not yet provided in packet_header
+            if packet_header.getlayer(0).name == 'Ethernet':
+                p = (packet_header /
+                     Raw(payload))
+            else:
+                p = (Ether(dst=src_if.local_mac, src=src_if.remote_mac) /
+                     packet_header /
+                     Raw(payload))
+            size = packet_sizes[i % len(packet_sizes)]
+            self.logger.debug("Packet size %d" % (size))
+            self.extend_packet(p, size)
+            # we need to store the packet with the automatic fields computed
+            # read back the dumped packet (with str())
+            # to force computing these fields
+            # probably other ways are possible
+            p = Ether(str(p))
+            payload_info.data = p.copy()
+            self.logger.debug(ppp("Created packet:", p))
+            pkts.append(p)
+        self.logger.info("Done creating packets")
+        return pkts
+
+    def send_and_verify_pkts(self, input, pkts, output, compare_func):
+        """Send packets and verify received packets using compare_func
+
+        :param input: ingress interface of DUT
+        :param pkts: list of packets to transmit
+        :param output: egress interface of DUT
+        :param compare_func: function to compare in and out packets
+        """
+        # add traffic stream to input interface
+        input.add_stream(pkts)
+
+        # enable capture on all interfaces
+        self.pg_enable_capture(self.pg_interfaces)
+
+        # start traffic
+        self.logger.info("Starting traffic")
+        self.pg_start()
+
+        # get output capture
+        self.logger.info("Getting packet capture")
+        capture = output.get_capture()
+
+        # assert nothing was captured on input interface
+        # input.assert_nothing_captured()
+
+        # verify captured packets
+        self.verify_captured_pkts(output, capture, compare_func)
+
+    def create_packet_header_IPv6(self):
+        """Create packet header: IPv6 header, UDP header
+
+        :param dst: IPv6 destination address
+
+        IPv6 source address is 1234::1
+        IPv6 destination address is 4321::1
+        UDP source port and destination port are 1234
+        """
+
+        p = (IPv6(src='1234::1', dst='4321::1') /
+             UDP(sport=1234, dport=1234))
+        return p
+
+    def create_packet_header_IPv6_SRH_IPv6(self, sidlist, segleft):
+        """Create packet header: IPv6 encapsulated in SRv6:
+        IPv6 header with SRH, IPv6 header, UDP header
+
+        :param list sidlist: segment list of outer IPv6 SRH
+        :param int segleft: segments-left field of outer IPv6 SRH
+
+        Outer IPv6 source address is set to 5678::1
+        Outer IPv6 destination address is set to sidlist[segleft]
+        IPv6 source addresses is 1234::1
+        IPv6 destination address is 4321::1
+        UDP source port and destination port are 1234
+        """
+
+        p = (IPv6(src='5678::1', dst=sidlist[segleft]) /
+             IPv6ExtHdrSegmentRouting(addresses=sidlist,
+                                      segleft=segleft, nh=41) /
+             IPv6(src='1234::1', dst='4321::1') /
+             UDP(sport=1234, dport=1234))
+        return p
+
+    def create_packet_header_IPv4(self):
+        """Create packet header: IPv4 header, UDP header
+
+        :param dst: IPv4 destination address
+
+        IPv4 source address is 123.1.1.1
+        IPv4 destination address is 124.1.1.1
+        UDP source port and destination port are 1234
+        """
+
+        p = (IP(src='123.1.1.1', dst='124.1.1.1') /
+             UDP(sport=1234, dport=1234))
+        return p
+
+    def create_packet_header_IPv6_SRH_IPv4(self, sidlist, segleft):
+        """Create packet header: IPv4 encapsulated in SRv6:
+        IPv6 header with SRH, IPv4 header, UDP header
+
+        :param ipv4address dst: inner IPv4 destination address
+        :param list sidlist: segment list of outer IPv6 SRH
+        :param int segleft: segments-left field of outer IPv6 SRH
+
+        Outer IPv6 destination address is set to sidlist[segleft]
+        IPv6 source address is 1234::1
+        IPv4 source address is 123.1.1.1
+        IPv4 destination address is 124.1.1.1
+        UDP source port and destination port are 1234
+        """
+
+        p = (IPv6(src='1234::1', dst=sidlist[segleft]) /
+             IPv6ExtHdrSegmentRouting(addresses=sidlist,
+                                      segleft=segleft, nh=4) /
+             IP(src='123.1.1.1', dst='124.1.1.1') /
+             UDP(sport=1234, dport=1234))
+        return p
+
+    def get_payload_info(self, packet):
+        """ Extract the payload_info from the packet
+        """
+        # in most cases, payload_info is in packet[Raw]
+        # but packet[Raw] gives the complete payload
+        # (incl L2 header) for the T.Encaps L2 case
+        try:
+            payload_info = self.payload_to_info(str(packet[Raw]))
+
+        except:
+            # remote L2 header from packet[Raw]:
+            # take packet[Raw], convert it to an Ether layer
+            # and then extract Raw from it
+            payload_info = self.payload_to_info(
+                str(Ether(str(packet[Raw]))[Raw]))
+
+        return payload_info
+
+    def verify_captured_pkts(self, dst_if, capture, compare_func):
+        """
+        Verify captured packet stream for specified interface.
+        Compare ingress with egress packets using the specified compare fn
+
+        :param dst_if: egress interface of DUT
+        :param capture: captured packets
+        :param compare_func: function to compare in and out packet
+        """
+        self.logger.info("Verifying capture on interface %s using function %s"
+                         % (dst_if.name, compare_func.func_name))
+
+        last_info = dict()
+        for i in self.pg_interfaces:
+            last_info[i.sw_if_index] = None
+        dst_sw_if_index = dst_if.sw_if_index
+
+        for packet in capture:
+            try:
+                # extract payload_info from packet's payload
+                payload_info = self.get_payload_info(packet)
+                packet_index = payload_info.index
+
+                self.logger.debug("Verifying packet with index %d"
+                                  % (packet_index))
+                # packet should have arrived on the expected interface
+                self.assertEqual(payload_info.dst, dst_sw_if_index)
+                self.logger.debug(
+                    "Got packet on interface %s: src=%u (idx=%u)" %
+                    (dst_if.name, payload_info.src, packet_index))
+
+                # search for payload_info with same src and dst if_index
+                # this will give us the transmitted packet
+                next_info = self.get_next_packet_info_for_interface2(
+                    payload_info.src, dst_sw_if_index,
+                    last_info[payload_info.src])
+                last_info[payload_info.src] = next_info
+                # next_info should not be None
+                self.assertTrue(next_info is not None)
+                # index of tx and rx packets should be equal
+                self.assertEqual(packet_index, next_info.index)
+                # data field of next_info contains the tx packet
+                txed_packet = next_info.data
+
+                self.logger.debug(ppp("Transmitted packet:",
+                                      txed_packet))  # ppp=Pretty Print Packet
+
+                self.logger.debug(ppp("Received packet:", packet))
+
+                # compare rcvd packet with expected packet using compare_func
+                compare_func(txed_packet, packet)
+
+            except:
+                print packet.command()
+                self.logger.error(ppp("Unexpected or invalid packet:", packet))
+                raise
+
+        # have all expected packets arrived?
+        for i in self.pg_interfaces:
+            remaining_packet = self.get_next_packet_info_for_interface2(
+                i.sw_if_index, dst_sw_if_index, last_info[i.sw_if_index])
+            self.assertTrue(remaining_packet is None,
+                            "Interface %s: Packet expected from interface %s "
+                            "didn't arrive" % (dst_if.name, i.name))
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)