#!/usr/bin/env python3

import ipaddress
import random
import socket
import struct
import unittest
from io import BytesIO

import scapy.compat
from framework import VppTestCase, VppTestRunner
from ipfix import IPFIX, Set, Template, Data, IPFIXDecoder
from scapy.all import bind_layers, Packet, ByteEnumField, ShortField, \
    IPField, IntField, LongField, XByteField, FlagsField, FieldLenField, \
    PacketListField
from scapy.data import IP_PROTOS
from scapy.layers.inet import IP, TCP, UDP, ICMP
from scapy.layers.inet import IPerror, TCPerror, UDPerror, ICMPerror
from scapy.layers.inet6 import IPv6, ICMPv6EchoRequest, ICMPv6EchoReply
from scapy.layers.l2 import Ether, ARP, GRE
from scapy.packet import Raw
from syslog_rfc5424_parser import SyslogMessage, ParseError
from syslog_rfc5424_parser.constants import SyslogSeverity
from util import ppp
from vpp_ip_route import VppIpRoute, VppRoutePath
from vpp_neighbor import VppNeighbor
from vpp_papi import VppEnum


# NAT HA protocol event data
class Event(Packet):
    name = "Event"
    fields_desc = [ByteEnumField("event_type", None,
                                 {1: "add", 2: "del", 3: "refresh"}),
                   ByteEnumField("protocol", None,
                                 {0: "other", 1: "udp", 2: "tcp", 3: "icmp"}),
                   ShortField("flags", 0),
                   IPField("in_addr", None),
                   IPField("out_addr", None),
                   ShortField("in_port", None),
                   ShortField("out_port", None),
                   IPField("eh_addr", None),
                   IPField("ehn_addr", None),
                   ShortField("eh_port", None),
                   ShortField("ehn_port", None),
                   IntField("fib_index", None),
                   IntField("total_pkts", 0),
                   LongField("total_bytes", 0)]

    def extract_padding(self, s):
        return "", s


# NAT HA protocol header
class HANATStateSync(Packet):
    name = "HA NAT state sync"
    fields_desc = [XByteField("version", 1),
                   FlagsField("flags", 0, 8, ['ACK']),
                   FieldLenField("count", None, count_of="events"),
                   IntField("sequence_number", 1),
                   IntField("thread_index", 0),
                   PacketListField("events", [], Event,
                                   count_from=lambda pkt: pkt.count)]


class MethodHolder(VppTestCase):
    """ NAT create capture and verify method holder """

    @property
    def config_flags(self):
        return VppEnum.vl_api_nat44_ei_config_flags_t

    @property
    def SYSLOG_SEVERITY(self):
        return VppEnum.vl_api_syslog_severity_t

    def nat44_add_static_mapping(self, local_ip, external_ip='0.0.0.0',
                                 local_port=0, external_port=0, vrf_id=0,
                                 is_add=1, external_sw_if_index=0xFFFFFFFF,
                                 proto=0, tag="", flags=0):
        """
        Add/delete NAT44EI static mapping

        :param local_ip: Local IP address
        :param external_ip: External IP address
        :param local_port: Local port number (Optional)
        :param external_port: External port number (Optional)
        :param vrf_id: VRF ID (Default 0)
        :param is_add: 1 if add, 0 if delete (Default add)
        :param external_sw_if_index: External interface instead of IP address
        :param proto: IP protocol (Mandatory if port specified)
        :param tag: Opaque string tag
        :param flags: NAT configuration flags
        """

        if not (local_port and external_port):
            flags |= self.config_flags.NAT44_EI_ADDR_ONLY_MAPPING

        self.vapi.nat44_ei_add_del_static_mapping(
            is_add=is_add,
            local_ip_address=local_ip,
            external_ip_address=external_ip,
            external_sw_if_index=external_sw_if_index,
            local_port=local_port,
            external_port=external_port,
            vrf_id=vrf_id, protocol=proto,
            flags=flags,
            tag=tag)

    def nat44_add_address(self, ip, is_add=1, vrf_id=0xFFFFFFFF):
        """
        Add/delete NAT44EI address

        :param ip: IP address
        :param is_add: 1 if add, 0 if delete (Default add)
        """
        self.vapi.nat44_ei_add_del_address_range(first_ip_address=ip,
                                                 last_ip_address=ip,
                                                 vrf_id=vrf_id,
                                                 is_add=is_add)

    def create_routes_and_neigbors(self):
        r1 = VppIpRoute(self, self.pg7.remote_ip4, 32,
                        [VppRoutePath(self.pg7.remote_ip4,
                                      self.pg7.sw_if_index)])
        r2 = VppIpRoute(self, self.pg8.remote_ip4, 32,
                        [VppRoutePath(self.pg8.remote_ip4,
                                      self.pg8.sw_if_index)])
        r1.add_vpp_config()
        r2.add_vpp_config()

        n1 = VppNeighbor(self,
                         self.pg7.sw_if_index,
                         self.pg7.remote_mac,
                         self.pg7.remote_ip4,
                         is_static=1)
        n2 = VppNeighbor(self,
                         self.pg8.sw_if_index,
                         self.pg8.remote_mac,
                         self.pg8.remote_ip4,
                         is_static=1)
        n1.add_vpp_config()
        n2.add_vpp_config()

    def create_stream_in(self, in_if, out_if, dst_ip=None, ttl=64):
        """
        Create packet stream for inside network

        :param in_if: Inside interface
        :param out_if: Outside interface
        :param dst_ip: Destination address
        :param ttl: TTL of generated packets
        """
        if dst_ip is None:
            dst_ip = out_if.remote_ip4

        pkts = []
        # TCP
        p = (Ether(dst=in_if.local_mac, src=in_if.remote_mac) /
             IP(src=in_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             TCP(sport=self.tcp_port_in, dport=20))
        pkts.extend([p, p])

        # UDP
        p = (Ether(dst=in_if.local_mac, src=in_if.remote_mac) /
             IP(src=in_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             UDP(sport=self.udp_port_in, dport=20))
        pkts.append(p)

        # ICMP
        p = (Ether(dst=in_if.local_mac, src=in_if.remote_mac) /
             IP(src=in_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             ICMP(id=self.icmp_id_in, type='echo-request'))
        pkts.append(p)

        return pkts

    def compose_ip6(self, ip4, pref, plen):
        """
        Compose IPv4-embedded IPv6 addresses

        :param ip4: IPv4 address
        :param pref: IPv6 prefix
        :param plen: IPv6 prefix length
        :returns: IPv4-embedded IPv6 addresses
        """
        pref_n = list(socket.inet_pton(socket.AF_INET6, pref))
        ip4_n = list(socket.inet_pton(socket.AF_INET, ip4))
        if plen == 32:
            pref_n[4] = ip4_n[0]
            pref_n[5] = ip4_n[1]
            pref_n[6] = ip4_n[2]
            pref_n[7] = ip4_n[3]
        elif plen == 40:
            pref_n[5] = ip4_n[0]
            pref_n[6] = ip4_n[1]
            pref_n[7] = ip4_n[2]
            pref_n[9] = ip4_n[3]
        elif plen == 48:
            pref_n[6] = ip4_n[0]
            pref_n[7] = ip4_n[1]
            pref_n[9] = ip4_n[2]
            pref_n[10] = ip4_n[3]
        elif plen == 56:
            pref_n[7] = ip4_n[0]
            pref_n[9] = ip4_n[1]
            pref_n[10] = ip4_n[2]
            pref_n[11] = ip4_n[3]
        elif plen == 64:
            pref_n[9] = ip4_n[0]
            pref_n[10] = ip4_n[1]
            pref_n[11] = ip4_n[2]
            pref_n[12] = ip4_n[3]
        elif plen == 96:
            pref_n[12] = ip4_n[0]
            pref_n[13] = ip4_n[1]
            pref_n[14] = ip4_n[2]
            pref_n[15] = ip4_n[3]
        packed_pref_n = b''.join([scapy.compat.chb(x) for x in pref_n])
        return socket.inet_ntop(socket.AF_INET6, packed_pref_n)

    def create_stream_out(self, out_if, dst_ip=None, ttl=64,
                          use_inside_ports=False):
        """
        Create packet stream for outside network

        :param out_if: Outside interface
        :param dst_ip: Destination IP address (Default use global NAT address)
        :param ttl: TTL of generated packets
        :param use_inside_ports: Use inside NAT ports as destination ports
               instead of outside ports
        """
        if dst_ip is None:
            dst_ip = self.nat_addr
        if not use_inside_ports:
            tcp_port = self.tcp_port_out
            udp_port = self.udp_port_out
            icmp_id = self.icmp_id_out
        else:
            tcp_port = self.tcp_port_in
            udp_port = self.udp_port_in
            icmp_id = self.icmp_id_in
        pkts = []
        # TCP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IP(src=out_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             TCP(dport=tcp_port, sport=20))
        pkts.extend([p, p])

        # UDP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IP(src=out_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             UDP(dport=udp_port, sport=20))
        pkts.append(p)

        # ICMP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IP(src=out_if.remote_ip4, dst=dst_ip, ttl=ttl) /
             ICMP(id=icmp_id, type='echo-reply'))
        pkts.append(p)

        return pkts

    def create_stream_out_ip6(self, out_if, src_ip, dst_ip, hl=64):
        """
        Create packet stream for outside network

        :param out_if: Outside interface
        :param dst_ip: Destination IP address (Default use global NAT address)
        :param hl: HL of generated packets
        """
        pkts = []
        # TCP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IPv6(src=src_ip, dst=dst_ip, hlim=hl) /
             TCP(dport=self.tcp_port_out, sport=20))
        pkts.append(p)

        # UDP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IPv6(src=src_ip, dst=dst_ip, hlim=hl) /
             UDP(dport=self.udp_port_out, sport=20))
        pkts.append(p)

        # ICMP
        p = (Ether(dst=out_if.local_mac, src=out_if.remote_mac) /
             IPv6(src=src_ip, dst=dst_ip, hlim=hl) /
             ICMPv6EchoReply(id=self.icmp_id_out))
        pkts.append(p)

        return pkts

    def verify_capture_out(self, capture, nat_ip=None, same_port=False,
                           dst_ip=None, is_ip6=False, ignore_port=False):
        """
        Verify captured packets on outside network

        :param capture: Captured packets
        :param nat_ip: Translated IP address (Default use global NAT address)
        :param same_port: Source port number is not translated (Default False)
        :param dst_ip: Destination IP address (Default do not verify)
        :param is_ip6: If L3 protocol is IPv6 (Default False)
        """
        if is_ip6:
            IP46 = IPv6
            ICMP46 = ICMPv6EchoRequest
        else:
            IP46 = IP
            ICMP46 = ICMP
        if nat_ip is None:
            nat_ip = self.nat_addr
        for packet in capture:
            try:
                if not is_ip6:
                    self.assert_packet_checksums_valid(packet)
                self.assertEqual(packet[IP46].src, nat_ip)
                if dst_ip is not None:
                    self.assertEqual(packet[IP46].dst, dst_ip)
                if packet.haslayer(TCP):
                    if not ignore_port:
                        if same_port:
                            self.assertEqual(
                                packet[TCP].sport, self.tcp_port_in)
                        else:
                            self.assertNotEqual(
                                packet[TCP].sport, self.tcp_port_in)
                    self.tcp_port_out = packet[TCP].sport
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    if not ignore_port:
                        if same_port:
                            self.assertEqual(
                                packet[UDP].sport, self.udp_port_in)
                        else:
                            self.assertNotEqual(
                                packet[UDP].sport, self.udp_port_in)
                    self.udp_port_out = packet[UDP].sport
                else:
                    if not ignore_port:
                        if same_port:
                            self.assertEqual(
                                packet[ICMP46].id, self.icmp_id_in)
                        else:
                            self.assertNotEqual(
                                packet[ICMP46].id, self.icmp_id_in)
                    self.icmp_id_out = packet[ICMP46].id
                    self.assert_packet_checksums_valid(packet)
            except:
                self.logger.error(ppp("Unexpected or invalid packet "
                                      "(outside network):", packet))
                raise

    def verify_capture_out_ip6(self, capture, nat_ip, same_port=False,
                               dst_ip=None):
        """
        Verify captured packets on outside network

        :param capture: Captured packets
        :param nat_ip: Translated IP address
        :param same_port: Source port number is not translated (Default False)
        :param dst_ip: Destination IP address (Default do not verify)
        """
        return self.verify_capture_out(capture, nat_ip, same_port, dst_ip,
                                       True)

    def verify_capture_in(self, capture, in_if):
        """
        Verify captured packets on inside network

        :param capture: Captured packets
        :param in_if: Inside interface
        """
        for packet in capture:
            try:
                self.assert_packet_checksums_valid(packet)
                self.assertEqual(packet[IP].dst, in_if.remote_ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].dport, self.udp_port_in)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet "
                                      "(inside network):", packet))
                raise

    def verify_capture_no_translation(self, capture, ingress_if, egress_if):
        """
        Verify captured packet that don't have to be translated

        :param capture: Captured packets
        :param ingress_if: Ingress interface
        :param egress_if: Egress interface
        """
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, ingress_if.remote_ip4)
                self.assertEqual(packet[IP].dst, egress_if.remote_ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].sport, self.tcp_port_in)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].sport, self.udp_port_in)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet "
                                      "(inside network):", packet))
                raise

    def verify_capture_out_with_icmp_errors(self, capture, src_ip=None,
                                            icmp_type=11):
        """
        Verify captured packets with ICMP errors on outside network

        :param capture: Captured packets
        :param src_ip: Translated IP address or IP address of VPP
                       (Default use global NAT address)
        :param icmp_type: Type of error ICMP packet
                          we are expecting (Default 11)
        """
        if src_ip is None:
            src_ip = self.nat_addr
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, src_ip)
                self.assertEqual(packet.haslayer(ICMP), 1)
                icmp = packet[ICMP]
                self.assertEqual(icmp.type, icmp_type)
                self.assertTrue(icmp.haslayer(IPerror))
                inner_ip = icmp[IPerror]
                if inner_ip.haslayer(TCPerror):
                    self.assertEqual(inner_ip[TCPerror].dport,
                                     self.tcp_port_out)
                elif inner_ip.haslayer(UDPerror):
                    self.assertEqual(inner_ip[UDPerror].dport,
                                     self.udp_port_out)
                else:
                    self.assertEqual(inner_ip[ICMPerror].id, self.icmp_id_out)
            except:
                self.logger.error(ppp("Unexpected or invalid packet "
                                      "(outside network):", packet))
                raise

    def verify_capture_in_with_icmp_errors(self, capture, in_if, icmp_type=11):
        """
        Verify captured packets with ICMP errors on inside network

        :param capture: Captured packets
        :param in_if: Inside interface
        :param icmp_type: Type of error ICMP packet
                          we are expecting (Default 11)
        """
        for packet in capture:
            try:
                self.assertEqual(packet[IP].dst, in_if.remote_ip4)
                self.assertEqual(packet.haslayer(ICMP), 1)
                icmp = packet[ICMP]
                self.assertEqual(icmp.type, icmp_type)
                self.assertTrue(icmp.haslayer(IPerror))
                inner_ip = icmp[IPerror]
                if inner_ip.haslayer(TCPerror):
                    self.assertEqual(inner_ip[TCPerror].sport,
                                     self.tcp_port_in)
                elif inner_ip.haslayer(UDPerror):
                    self.assertEqual(inner_ip[UDPerror].sport,
                                     self.udp_port_in)
                else:
                    self.assertEqual(inner_ip[ICMPerror].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet "
                                      "(inside network):", packet))
                raise

    def create_stream_frag(self, src_if, dst, sport, dport, data,
                           proto=IP_PROTOS.tcp, echo_reply=False):
        """
        Create fragmented packet stream

        :param src_if: Source interface
        :param dst: Destination IPv4 address
        :param sport: Source port
        :param dport: Destination port
        :param data: Payload data
        :param proto: protocol (TCP, UDP, ICMP)
        :param echo_reply: use echo_reply if protocol is ICMP
        :returns: Fragments
        """
        if proto == IP_PROTOS.tcp:
            p = (IP(src=src_if.remote_ip4, dst=dst) /
                 TCP(sport=sport, dport=dport) /
                 Raw(data))
            p = p.__class__(scapy.compat.raw(p))
            chksum = p[TCP].chksum
            proto_header = TCP(sport=sport, dport=dport, chksum=chksum)
        elif proto == IP_PROTOS.udp:
            proto_header = UDP(sport=sport, dport=dport)
        elif proto == IP_PROTOS.icmp:
            if not echo_reply:
                proto_header = ICMP(id=sport, type='echo-request')
            else:
                proto_header = ICMP(id=sport, type='echo-reply')
        else:
            raise Exception("Unsupported protocol")
        id = random.randint(0, 65535)
        pkts = []
        if proto == IP_PROTOS.tcp:
            raw = Raw(data[0:4])
        else:
            raw = Raw(data[0:16])
        p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
             IP(src=src_if.remote_ip4, dst=dst, flags="MF", frag=0, id=id) /
             proto_header /
             raw)
        pkts.append(p)
        if proto == IP_PROTOS.tcp:
            raw = Raw(data[4:20])
        else:
            raw = Raw(data[16:32])
        p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
             IP(src=src_if.remote_ip4, dst=dst, flags="MF", frag=3, id=id,
                proto=proto) /
             raw)
        pkts.append(p)
        if proto == IP_PROTOS.tcp:
            raw = Raw(data[20:])
        else:
            raw = Raw(data[32:])
        p = (Ether(src=src_if.remote_mac, dst=src_if.local_mac) /
             IP(src=src_if.remote_ip4, dst=dst, frag=5, proto=proto,
                id=id) /
             raw)
        pkts.append(p)
        return pkts

    def reass_frags_and_verify(self, frags, src, dst):
        """
        Reassemble and verify fragmented packet

        :param frags: Captured fragments
        :param src: Source IPv4 address to verify
        :param dst: Destination IPv4 address to verify

        :returns: Reassembled IPv4 packet
        """
        buffer = BytesIO()
        for p in frags:
            self.assertEqual(p[IP].src, src)
            self.assertEqual(p[IP].dst, dst)
            self.assert_ip_checksum_valid(p)
            buffer.seek(p[IP].frag * 8)
            buffer.write(bytes(p[IP].payload))
        ip = IP(src=frags[0][IP].src, dst=frags[0][IP].dst,
                proto=frags[0][IP].proto)
        if ip.proto == IP_PROTOS.tcp:
            p = (ip / TCP(buffer.getvalue()))
            self.logger.debug(ppp("Reassembled:", p))
            self.assert_tcp_checksum_valid(p)
        elif ip.proto == IP_PROTOS.udp:
            p = (ip / UDP(buffer.getvalue()[:8]) /
                 Raw(buffer.getvalue()[8:]))
        elif ip.proto == IP_PROTOS.icmp:
            p = (ip / ICMP(buffer.getvalue()))
        return p

    def verify_ipfix_nat44_ses(self, data):
        """
        Verify IPFIX NAT44EI session create/delete event

        :param data: Decoded IPFIX data records
        """
        nat44_ses_create_num = 0
        nat44_ses_delete_num = 0
        self.assertEqual(6, len(data))
        for record in data:
            # natEvent
            self.assertIn(scapy.compat.orb(record[230]), [4, 5])
            if scapy.compat.orb(record[230]) == 4:
                nat44_ses_create_num += 1
            else:
                nat44_ses_delete_num += 1
            # sourceIPv4Address
            self.assertEqual(self.pg0.remote_ip4,
                             str(ipaddress.IPv4Address(record[8])))
            # postNATSourceIPv4Address
            self.assertEqual(socket.inet_pton(socket.AF_INET, self.nat_addr),
                             record[225])
            # ingressVRFID
            self.assertEqual(struct.pack("!I", 0), record[234])
            # protocolIdentifier/sourceTransportPort
            # /postNAPTSourceTransportPort
            if IP_PROTOS.icmp == scapy.compat.orb(record[4]):
                self.assertEqual(struct.pack("!H", self.icmp_id_in), record[7])
                self.assertEqual(struct.pack("!H", self.icmp_id_out),
                                 record[227])
            elif IP_PROTOS.tcp == scapy.compat.orb(record[4]):
                self.assertEqual(struct.pack("!H", self.tcp_port_in),
                                 record[7])
                self.assertEqual(struct.pack("!H", self.tcp_port_out),
                                 record[227])
            elif IP_PROTOS.udp == scapy.compat.orb(record[4]):
                self.assertEqual(struct.pack("!H", self.udp_port_in),
                                 record[7])
                self.assertEqual(struct.pack("!H", self.udp_port_out),
                                 record[227])
            else:
                self.fail(f"Invalid protocol {scapy.compat.orb(record[4])}")
        self.assertEqual(3, nat44_ses_create_num)
        self.assertEqual(3, nat44_ses_delete_num)

    def verify_ipfix_addr_exhausted(self, data):
        self.assertEqual(1, len(data))
        record = data[0]
        # natEvent
        self.assertEqual(scapy.compat.orb(record[230]), 3)
        # natPoolID
        self.assertEqual(struct.pack("!I", 0), record[283])

    def verify_ipfix_max_sessions(self, data, limit):
        self.assertEqual(1, len(data))
        record = data[0]
        # natEvent
        self.assertEqual(scapy.compat.orb(record[230]), 13)
        # natQuotaExceededEvent
        self.assertEqual(struct.pack("!I", 1), record[466])
        # maxSessionEntries
        self.assertEqual(struct.pack("!I", limit), record[471])

    def verify_no_nat44_user(self):
        """ Verify that there is no NAT44EI user """
        users = self.vapi.nat44_ei_user_dump()
        self.assertEqual(len(users), 0)
        users = self.statistics['/nat44-ei/total-users']
        self.assertEqual(users[0][0], 0)
        sessions = self.statistics['/nat44-ei/total-sessions']
        self.assertEqual(sessions[0][0], 0)

    def verify_syslog_apmap(self, data, is_add=True):
        message = data.decode('utf-8')
        try:
            message = SyslogMessage.parse(message)
        except ParseError as e:
            self.logger.error(e)
            raise
        else:
            self.assertEqual(message.severity, SyslogSeverity.info)
            self.assertEqual(message.appname, 'NAT')
            self.assertEqual(message.msgid, 'APMADD' if is_add else 'APMDEL')
            sd_params = message.sd.get('napmap')
            self.assertTrue(sd_params is not None)
            self.assertEqual(sd_params.get('IATYP'), 'IPv4')
            self.assertEqual(sd_params.get('ISADDR'), self.pg0.remote_ip4)
            self.assertEqual(sd_params.get('ISPORT'), "%d" % self.tcp_port_in)
            self.assertEqual(sd_params.get('XATYP'), 'IPv4')
            self.assertEqual(sd_params.get('XSADDR'), self.nat_addr)
            self.assertEqual(sd_params.get('XSPORT'), "%d" % self.tcp_port_out)
            self.assertEqual(sd_params.get('PROTO'), "%d" % IP_PROTOS.tcp)
            self.assertTrue(sd_params.get('SSUBIX') is not None)
            self.assertEqual(sd_params.get('SVLAN'), '0')

    def verify_mss_value(self, pkt, mss):
        if not pkt.haslayer(IP) or not pkt.haslayer(TCP):
            raise TypeError("Not a TCP/IP packet")

        for option in pkt[TCP].options:
            if option[0] == 'MSS':
                self.assertEqual(option[1], mss)
                self.assert_tcp_checksum_valid(pkt)

    @staticmethod
    def proto2layer(proto):
        if proto == IP_PROTOS.tcp:
            return TCP
        elif proto == IP_PROTOS.udp:
            return UDP
        elif proto == IP_PROTOS.icmp:
            return ICMP
        else:
            raise Exception("Unsupported protocol")

    def frag_in_order(self, proto=IP_PROTOS.tcp, dont_translate=False,
                      ignore_port=False):
        layer = self.proto2layer(proto)

        if proto == IP_PROTOS.tcp:
            data = b"A" * 4 + b"B" * 16 + b"C" * 3
        else:
            data = b"A" * 16 + b"B" * 16 + b"C" * 3
        self.port_in = random.randint(1025, 65535)

        # in2out
        pkts = self.create_stream_frag(self.pg0, self.pg1.remote_ip4,
                                       self.port_in, 20, data, proto)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        frags = self.pg1.get_capture(len(pkts))
        if not dont_translate:
            p = self.reass_frags_and_verify(frags,
                                            self.nat_addr,
                                            self.pg1.remote_ip4)
        else:
            p = self.reass_frags_and_verify(frags,
                                            self.pg0.remote_ip4,
                                            self.pg1.remote_ip4)
        if proto != IP_PROTOS.icmp:
            if not dont_translate:
                self.assertEqual(p[layer].dport, 20)
                if not ignore_port:
                    self.assertNotEqual(p[layer].sport, self.port_in)
            else:
                self.assertEqual(p[layer].sport, self.port_in)
        else:
            if not ignore_port:
                if not dont_translate:
                    self.assertNotEqual(p[layer].id, self.port_in)
                else:
                    self.assertEqual(p[layer].id, self.port_in)
        self.assertEqual(data, p[Raw].load)

        # out2in
        if not dont_translate:
            dst_addr = self.nat_addr
        else:
            dst_addr = self.pg0.remote_ip4
        if proto != IP_PROTOS.icmp:
            sport = 20
            dport = p[layer].sport
        else:
            sport = p[layer].id
            dport = 0
        pkts = self.create_stream_frag(self.pg1, dst_addr, sport, dport, data,
                                       proto, echo_reply=True)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        frags = self.pg0.get_capture(len(pkts))
        p = self.reass_frags_and_verify(frags,
                                        self.pg1.remote_ip4,
                                        self.pg0.remote_ip4)
        if proto != IP_PROTOS.icmp:
            self.assertEqual(p[layer].sport, 20)
            self.assertEqual(p[layer].dport, self.port_in)
        else:
            self.assertEqual(p[layer].id, self.port_in)
        self.assertEqual(data, p[Raw].load)

    def reass_hairpinning(self, server_addr, server_in_port, server_out_port,
                          host_in_port, proto=IP_PROTOS.tcp,
                          ignore_port=False):

        layer = self.proto2layer(proto)

        if proto == IP_PROTOS.tcp:
            data = b"A" * 4 + b"B" * 16 + b"C" * 3
        else:
            data = b"A" * 16 + b"B" * 16 + b"C" * 3

        # send packet from host to server
        pkts = self.create_stream_frag(self.pg0,
                                       self.nat_addr,
                                       host_in_port,
                                       server_out_port,
                                       data,
                                       proto)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        frags = self.pg0.get_capture(len(pkts))
        p = self.reass_frags_and_verify(frags,
                                        self.nat_addr,
                                        server_addr)
        if proto != IP_PROTOS.icmp:
            if not ignore_port:
                self.assertNotEqual(p[layer].sport, host_in_port)
            self.assertEqual(p[layer].dport, server_in_port)
        else:
            if not ignore_port:
                self.assertNotEqual(p[layer].id, host_in_port)
        self.assertEqual(data, p[Raw].load)

    def frag_out_of_order(self, proto=IP_PROTOS.tcp, dont_translate=False,
                          ignore_port=False):
        layer = self.proto2layer(proto)

        if proto == IP_PROTOS.tcp:
            data = b"A" * 4 + b"B" * 16 + b"C" * 3
        else:
            data = b"A" * 16 + b"B" * 16 + b"C" * 3
        self.port_in = random.randint(1025, 65535)

        for i in range(2):
            # in2out
            pkts = self.create_stream_frag(self.pg0, self.pg1.remote_ip4,
                                           self.port_in, 20, data, proto)
            pkts.reverse()
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            frags = self.pg1.get_capture(len(pkts))
            if not dont_translate:
                p = self.reass_frags_and_verify(frags,
                                                self.nat_addr,
                                                self.pg1.remote_ip4)
            else:
                p = self.reass_frags_and_verify(frags,
                                                self.pg0.remote_ip4,
                                                self.pg1.remote_ip4)
            if proto != IP_PROTOS.icmp:
                if not dont_translate:
                    self.assertEqual(p[layer].dport, 20)
                    if not ignore_port:
                        self.assertNotEqual(p[layer].sport, self.port_in)
                else:
                    self.assertEqual(p[layer].sport, self.port_in)
            else:
                if not ignore_port:
                    if not dont_translate:
                        self.assertNotEqual(p[layer].id, self.port_in)
                    else:
                        self.assertEqual(p[layer].id, self.port_in)
            self.assertEqual(data, p[Raw].load)

            # out2in
            if not dont_translate:
                dst_addr = self.nat_addr
            else:
                dst_addr = self.pg0.remote_ip4
            if proto != IP_PROTOS.icmp:
                sport = 20
                dport = p[layer].sport
            else:
                sport = p[layer].id
                dport = 0
            pkts = self.create_stream_frag(self.pg1, dst_addr, sport, dport,
                                           data, proto, echo_reply=True)
            pkts.reverse()
            self.pg1.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            frags = self.pg0.get_capture(len(pkts))
            p = self.reass_frags_and_verify(frags,
                                            self.pg1.remote_ip4,
                                            self.pg0.remote_ip4)
            if proto != IP_PROTOS.icmp:
                self.assertEqual(p[layer].sport, 20)
                self.assertEqual(p[layer].dport, self.port_in)
            else:
                self.assertEqual(p[layer].id, self.port_in)
            self.assertEqual(data, p[Raw].load)


def get_nat44_ei_in2out_worker_index(ip, vpp_worker_count):
    if 0 == vpp_worker_count:
        return 0
    numeric = socket.inet_aton(ip)
    numeric = struct.unpack("!L", numeric)[0]
    numeric = socket.htonl(numeric)
    h = numeric + (numeric >> 8) + (numeric >> 16) + (numeric >> 24)
    return 1 + h % vpp_worker_count


class TestNAT44EI(MethodHolder):
    """ NAT44EI Test Cases """

    max_translations = 10240
    max_users = 10240

    @classmethod
    def setUpClass(cls):
        super(TestNAT44EI, cls).setUpClass()
        cls.vapi.cli("set log class nat44-ei level debug")

        cls.tcp_port_in = 6303
        cls.tcp_port_out = 6303
        cls.udp_port_in = 6304
        cls.udp_port_out = 6304
        cls.icmp_id_in = 6305
        cls.icmp_id_out = 6305
        cls.nat_addr = '10.0.0.3'
        cls.ipfix_src_port = 4739
        cls.ipfix_domain_id = 1
        cls.tcp_external_port = 80
        cls.udp_external_port = 69

        cls.create_pg_interfaces(range(10))
        cls.interfaces = list(cls.pg_interfaces[0:4])

        for i in cls.interfaces:
            i.admin_up()
            i.config_ip4()
            i.resolve_arp()

        cls.pg0.generate_remote_hosts(3)
        cls.pg0.configure_ipv4_neighbors()

        cls.pg1.generate_remote_hosts(1)
        cls.pg1.configure_ipv4_neighbors()

        cls.overlapping_interfaces = list(list(cls.pg_interfaces[4:7]))
        cls.vapi.ip_table_add_del(is_add=1, table={'table_id': 10})
        cls.vapi.ip_table_add_del(is_add=1, table={'table_id': 20})

        cls.pg4._local_ip4 = "172.16.255.1"
        cls.pg4._remote_hosts[0]._ip4 = "172.16.255.2"
        cls.pg4.set_table_ip4(10)
        cls.pg5._local_ip4 = "172.17.255.3"
        cls.pg5._remote_hosts[0]._ip4 = "172.17.255.4"
        cls.pg5.set_table_ip4(10)
        cls.pg6._local_ip4 = "172.16.255.1"
        cls.pg6._remote_hosts[0]._ip4 = "172.16.255.2"
        cls.pg6.set_table_ip4(20)
        for i in cls.overlapping_interfaces:
            i.config_ip4()
            i.admin_up()
            i.resolve_arp()

        cls.pg7.admin_up()
        cls.pg8.admin_up()

        cls.pg9.generate_remote_hosts(2)
        cls.pg9.config_ip4()
        cls.vapi.sw_interface_add_del_address(
            sw_if_index=cls.pg9.sw_if_index,
            prefix="10.0.0.1/24")

        cls.pg9.admin_up()
        cls.pg9.resolve_arp()
        cls.pg9._remote_hosts[1]._ip4 = cls.pg9._remote_hosts[0]._ip4
        cls.pg4._remote_ip4 = cls.pg9._remote_hosts[0]._ip4 = "10.0.0.2"
        cls.pg9.resolve_arp()

    def plugin_enable(self):
        self.vapi.nat44_ei_plugin_enable_disable(
            sessions=self.max_translations,
            users=self.max_users, enable=1)

    def setUp(self):
        super(TestNAT44EI, self).setUp()
        self.plugin_enable()

    def tearDown(self):
        super(TestNAT44EI, self).tearDown()
        if not self.vpp_dead:
            self.vapi.nat44_ei_ipfix_enable_disable(
                domain_id=self.ipfix_domain_id, src_port=self.ipfix_src_port,
                enable=0)
            self.ipfix_src_port = 4739
            self.ipfix_domain_id = 1

            self.vapi.nat44_ei_plugin_enable_disable(enable=0)
            self.vapi.cli("clear logging")

    def test_clear_sessions(self):
        """ NAT44EI session clearing test """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)

        sessions = self.statistics['/nat44-ei/total-sessions']
        self.assertGreater(sessions[:, 0].sum(), 0, "Session count invalid")
        self.logger.info("sessions before clearing: %s" % sessions[0][0])

        self.vapi.cli("clear nat44 ei sessions")

        sessions = self.statistics['/nat44-ei/total-sessions']
        self.assertEqual(sessions[:, 0].sum(), 0, "Session count invalid")
        self.logger.info("sessions after clearing: %s" % sessions[0][0])

    def test_dynamic(self):
        """ NAT44EI dynamic translation test """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # in2out
        tcpn = self.statistics['/nat44-ei/in2out/slowpath/tcp']
        udpn = self.statistics['/nat44-ei/in2out/slowpath/udp']
        icmpn = self.statistics['/nat44-ei/in2out/slowpath/icmp']
        drops = self.statistics['/nat44-ei/in2out/slowpath/drops']

        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)

        if_idx = self.pg0.sw_if_index
        cnt = self.statistics['/nat44-ei/in2out/slowpath/tcp']
        self.assertEqual(cnt[:, if_idx].sum() - tcpn[:, if_idx].sum(), 2)
        cnt = self.statistics['/nat44-ei/in2out/slowpath/udp']
        self.assertEqual(cnt[:, if_idx].sum() - udpn[:, if_idx].sum(), 1)
        cnt = self.statistics['/nat44-ei/in2out/slowpath/icmp']
        self.assertEqual(cnt[:, if_idx].sum() - icmpn[:, if_idx].sum(), 1)
        cnt = self.statistics['/nat44-ei/in2out/slowpath/drops']
        self.assertEqual(cnt[:, if_idx].sum() - drops[:, if_idx].sum(), 0)

        # out2in
        tcpn = self.statistics['/nat44-ei/out2in/slowpath/tcp']
        udpn = self.statistics['/nat44-ei/out2in/slowpath/udp']
        icmpn = self.statistics['/nat44-ei/out2in/slowpath/icmp']
        drops = self.statistics['/nat44-ei/out2in/slowpath/drops']

        pkts = self.create_stream_out(self.pg1)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

        if_idx = self.pg1.sw_if_index
        cnt = self.statistics['/nat44-ei/out2in/slowpath/tcp']
        self.assertEqual(cnt[:, if_idx].sum() - tcpn[:, if_idx].sum(), 2)
        cnt = self.statistics['/nat44-ei/out2in/slowpath/udp']
        self.assertEqual(cnt[:, if_idx].sum() - udpn[:, if_idx].sum(), 1)
        cnt = self.statistics['/nat44-ei/out2in/slowpath/icmp']
        self.assertEqual(cnt[:, if_idx].sum() - icmpn[:, if_idx].sum(), 1)
        cnt = self.statistics['/nat44-ei/out2in/slowpath/drops']
        self.assertEqual(cnt[:, if_idx].sum() - drops[:, if_idx].sum(), 0)

        users = self.statistics['/nat44-ei/total-users']
        self.assertEqual(users[:, 0].sum(), 1)
        sessions = self.statistics['/nat44-ei/total-sessions']
        self.assertEqual(sessions[:, 0].sum(), 3)

    def test_dynamic_icmp_errors_in2out_ttl_1(self):
        """ NAT44EI handling of client packets with TTL=1 """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # Client side - generate traffic
        pkts = self.create_stream_in(self.pg0, self.pg1, ttl=1)
        capture = self.send_and_expect_some(self.pg0, pkts, self.pg0)

        # Client side - verify ICMP type 11 packets
        self.verify_capture_in_with_icmp_errors(capture, self.pg0)

    def test_dynamic_icmp_errors_out2in_ttl_1(self):
        """ NAT44EI handling of server packets with TTL=1 """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # Client side - create sessions
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Server side - generate traffic
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)
        pkts = self.create_stream_out(self.pg1, ttl=1)
        capture = self.send_and_expect_some(self.pg1, pkts, self.pg1)

        # Server side - verify ICMP type 11 packets
        self.verify_capture_out_with_icmp_errors(capture,
                                                 src_ip=self.pg1.local_ip4)

    def test_dynamic_icmp_errors_in2out_ttl_2(self):
        """ NAT44EI handling of error responses to client packets with TTL=2
        """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # Client side - generate traffic
        pkts = self.create_stream_in(self.pg0, self.pg1, ttl=2)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Server side - simulate ICMP type 11 response
        capture = self.pg1.get_capture(len(pkts))
        pkts = [Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
                IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
                ICMP(type=11) / packet[IP] for packet in capture]
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Client side - verify ICMP type 11 packets
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in_with_icmp_errors(capture, self.pg0)

    def test_dynamic_icmp_errors_out2in_ttl_2(self):
        """ NAT44EI handling of error responses to server packets with TTL=2
        """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # Client side - create sessions
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Server side - generate traffic
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)
        pkts = self.create_stream_out(self.pg1, ttl=2)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Client side - simulate ICMP type 11 response
        capture = self.pg0.get_capture(len(pkts))
        pkts = [Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
                IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
                ICMP(type=11) / packet[IP] for packet in capture]
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        # Server side - verify ICMP type 11 packets
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out_with_icmp_errors(capture)

    def test_ping_out_interface_from_outside(self):
        """ NAT44EI ping out interface from outside network """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
             IP(src=self.pg1.remote_ip4, dst=self.pg1.local_ip4) /
             ICMP(id=self.icmp_id_out, type='echo-request'))
        pkts = [p]
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        packet = capture[0]
        try:
            self.assertEqual(packet[IP].src, self.pg1.local_ip4)
            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
            self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            self.assertEqual(packet[ICMP].type, 0)  # echo reply
        except:
            self.logger.error(ppp("Unexpected or invalid packet "
                                  "(outside network):", packet))
            raise

    def test_ping_internal_host_from_outside(self):
        """ NAT44EI ping internal host from outside network """

        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # out2in
        pkt = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
               IP(src=self.pg1.remote_ip4, dst=self.nat_addr, ttl=64) /
               ICMP(id=self.icmp_id_out, type='echo-request'))
        self.pg1.add_stream(pkt)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        self.verify_capture_in(capture, self.pg0)
        self.assert_equal(capture[0][IP].proto, IP_PROTOS.icmp)

        # in2out
        pkt = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
               IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4, ttl=64) /
               ICMP(id=self.icmp_id_in, type='echo-reply'))
        self.pg0.add_stream(pkt)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        self.verify_capture_out(capture, same_port=True)
        self.assert_equal(capture[0][IP].proto, IP_PROTOS.icmp)

    def test_forwarding(self):
        """ NAT44EI forwarding test """

        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_forwarding_enable_disable(enable=1)

        real_ip = self.pg0.remote_ip4
        alias_ip = self.nat_addr
        flags = self.config_flags.NAT44_EI_ADDR_ONLY_MAPPING
        self.vapi.nat44_ei_add_del_static_mapping(
            is_add=1, local_ip_address=real_ip,
            external_ip_address=alias_ip,
            external_sw_if_index=0xFFFFFFFF,
            flags=flags)

        try:
            # static mapping match

            pkts = self.create_stream_out(self.pg1)
            self.pg1.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg0.get_capture(len(pkts))
            self.verify_capture_in(capture, self.pg0)

            pkts = self.create_stream_in(self.pg0, self.pg1)
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg1.get_capture(len(pkts))
            self.verify_capture_out(capture, same_port=True)

            # no static mapping match

            host0 = self.pg0.remote_hosts[0]
            self.pg0.remote_hosts[0] = self.pg0.remote_hosts[1]
            try:
                pkts = self.create_stream_out(self.pg1,
                                              dst_ip=self.pg0.remote_ip4,
                                              use_inside_ports=True)
                self.pg1.add_stream(pkts)
                self.pg_enable_capture(self.pg_interfaces)
                self.pg_start()
                capture = self.pg0.get_capture(len(pkts))
                self.verify_capture_in(capture, self.pg0)

                pkts = self.create_stream_in(self.pg0, self.pg1)
                self.pg0.add_stream(pkts)
                self.pg_enable_capture(self.pg_interfaces)
                self.pg_start()
                capture = self.pg1.get_capture(len(pkts))
                self.verify_capture_out(capture, nat_ip=self.pg0.remote_ip4,
                                        same_port=True)
            finally:
                self.pg0.remote_hosts[0] = host0

        finally:
            self.vapi.nat44_ei_forwarding_enable_disable(enable=0)
            flags = self.config_flags.NAT44_EI_ADDR_ONLY_MAPPING
            self.vapi.nat44_ei_add_del_static_mapping(
                is_add=0,
                local_ip_address=real_ip,
                external_ip_address=alias_ip,
                external_sw_if_index=0xFFFFFFFF,
                flags=flags)

    def test_static_in(self):
        """ NAT44EI 1:1 NAT initialized from inside network """

        nat_ip = "10.0.0.10"
        self.tcp_port_out = 6303
        self.udp_port_out = 6304
        self.icmp_id_out = 6305

        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        sm = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(len(sm), 1)
        self.assertEqual(sm[0].tag, '')
        self.assertEqual(sm[0].protocol, 0)
        self.assertEqual(sm[0].local_port, 0)
        self.assertEqual(sm[0].external_port, 0)

        # in2out
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip, True)

        # out2in
        pkts = self.create_stream_out(self.pg1, nat_ip)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

    def test_static_out(self):
        """ NAT44EI 1:1 NAT initialized from outside network """

        nat_ip = "10.0.0.20"
        self.tcp_port_out = 6303
        self.udp_port_out = 6304
        self.icmp_id_out = 6305
        tag = "testTAG"

        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip, tag=tag)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        sm = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(len(sm), 1)
        self.assertEqual(sm[0].tag, tag)

        # out2in
        pkts = self.create_stream_out(self.pg1, nat_ip)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

        # in2out
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip, True)

    def test_static_with_port_in(self):
        """ NAT44EI 1:1 NAPT initialized from inside network """

        self.tcp_port_out = 3606
        self.udp_port_out = 3607
        self.icmp_id_out = 3608

        self.nat44_add_address(self.nat_addr)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.tcp_port_in, self.tcp_port_out,
                                      proto=IP_PROTOS.tcp)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.udp_port_in, self.udp_port_out,
                                      proto=IP_PROTOS.udp)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.icmp_id_in, self.icmp_id_out,
                                      proto=IP_PROTOS.icmp)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # in2out
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in
        pkts = self.create_stream_out(self.pg1)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

    def test_static_with_port_out(self):
        """ NAT44EI 1:1 NAPT initialized from outside network """

        self.tcp_port_out = 30606
        self.udp_port_out = 30607
        self.icmp_id_out = 30608

        self.nat44_add_address(self.nat_addr)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.tcp_port_in, self.tcp_port_out,
                                      proto=IP_PROTOS.tcp)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.udp_port_in, self.udp_port_out,
                                      proto=IP_PROTOS.udp)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, self.nat_addr,
                                      self.icmp_id_in, self.icmp_id_out,
                                      proto=IP_PROTOS.icmp)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # out2in
        pkts = self.create_stream_out(self.pg1)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

        # in2out
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)

    def test_static_vrf_aware(self):
        """ NAT44EI 1:1 NAT VRF awareness """

        nat_ip1 = "10.0.0.30"
        nat_ip2 = "10.0.0.40"
        self.tcp_port_out = 6303
        self.udp_port_out = 6304
        self.icmp_id_out = 6305

        self.nat44_add_static_mapping(self.pg4.remote_ip4, nat_ip1,
                                      vrf_id=10)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip2,
                                      vrf_id=10)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg3.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg4.sw_if_index,
            flags=flags, is_add=1)

        # inside interface VRF match NAT44EI static mapping VRF
        pkts = self.create_stream_in(self.pg4, self.pg3)
        self.pg4.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip1, True)

        # inside interface VRF don't match NAT44EI static mapping VRF (packets
        # are dropped)
        pkts = self.create_stream_in(self.pg0, self.pg3)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg3.assert_nothing_captured()

    def test_dynamic_to_static(self):
        """ NAT44EI Switch from dynamic translation to 1:1NAT """
        nat_ip = "10.0.0.10"
        self.tcp_port_out = 6303
        self.udp_port_out = 6304
        self.icmp_id_out = 6305

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # dynamic
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # 1:1NAT
        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip)
        sessions = self.vapi.nat44_ei_user_session_dump(self.pg0.remote_ip4, 0)
        self.assertEqual(len(sessions), 0)
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip, True)

    def test_identity_nat(self):
        """ NAT44EI Identity NAT """
        flags = self.config_flags.NAT44_EI_ADDR_ONLY_MAPPING
        self.vapi.nat44_ei_add_del_identity_mapping(
            ip_address=self.pg0.remote_ip4, sw_if_index=0xFFFFFFFF,
            flags=flags, is_add=1)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        p = (Ether(src=self.pg1.remote_mac, dst=self.pg1.local_mac) /
             IP(src=self.pg1.remote_ip4, dst=self.pg0.remote_ip4) /
             TCP(sport=12345, dport=56789))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.dst, self.pg0.remote_ip4)
            self.assertEqual(ip.src, self.pg1.remote_ip4)
            self.assertEqual(tcp.dport, 56789)
            self.assertEqual(tcp.sport, 12345)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        sessions = self.vapi.nat44_ei_user_session_dump(self.pg0.remote_ip4, 0)
        self.assertEqual(len(sessions), 0)
        flags = self.config_flags.NAT44_EI_ADDR_ONLY_MAPPING
        self.vapi.nat44_ei_add_del_identity_mapping(
            ip_address=self.pg0.remote_ip4, sw_if_index=0xFFFFFFFF,
            flags=flags, vrf_id=1, is_add=1)
        identity_mappings = self.vapi.nat44_ei_identity_mapping_dump()
        self.assertEqual(len(identity_mappings), 2)

    def test_multiple_inside_interfaces(self):
        """ NAT44EI multiple non-overlapping address space inside interfaces
        """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg3.sw_if_index,
            is_add=1)

        # between two NAT44EI inside interfaces (no translation)
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_no_translation(capture, self.pg0, self.pg1)

        # from inside to interface without translation
        pkts = self.create_stream_in(self.pg0, self.pg2)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg2.get_capture(len(pkts))
        self.verify_capture_no_translation(capture, self.pg0, self.pg2)

        # in2out 1st interface
        pkts = self.create_stream_in(self.pg0, self.pg3)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in 1st interface
        pkts = self.create_stream_out(self.pg3)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

        # in2out 2nd interface
        pkts = self.create_stream_in(self.pg1, self.pg3)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in 2nd interface
        pkts = self.create_stream_out(self.pg3)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg1)

    def test_inside_overlapping_interfaces(self):
        """ NAT44EI multiple inside interfaces with overlapping address space
        """

        static_nat_ip = "10.0.0.10"
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg3.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg4.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg5.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg6.sw_if_index,
            flags=flags, is_add=1)
        self.nat44_add_static_mapping(self.pg6.remote_ip4, static_nat_ip,
                                      vrf_id=20)

        # between NAT44EI inside interfaces with same VRF (no translation)
        pkts = self.create_stream_in(self.pg4, self.pg5)
        self.pg4.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg5.get_capture(len(pkts))
        self.verify_capture_no_translation(capture, self.pg4, self.pg5)

        # between NAT44EI inside interfaces with different VRF (hairpinning)
        p = (Ether(src=self.pg4.remote_mac, dst=self.pg4.local_mac) /
             IP(src=self.pg4.remote_ip4, dst=static_nat_ip) /
             TCP(sport=1234, dport=5678))
        self.pg4.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg6.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, self.pg6.remote_ip4)
            self.assertNotEqual(tcp.sport, 1234)
            self.assertEqual(tcp.dport, 5678)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        # in2out 1st interface
        pkts = self.create_stream_in(self.pg4, self.pg3)
        self.pg4.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in 1st interface
        pkts = self.create_stream_out(self.pg3)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg4.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg4)

        # in2out 2nd interface
        pkts = self.create_stream_in(self.pg5, self.pg3)
        self.pg5.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in 2nd interface
        pkts = self.create_stream_out(self.pg3)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg5.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg5)

        # pg5 session dump
        addresses = self.vapi.nat44_ei_address_dump()
        self.assertEqual(len(addresses), 1)
        sessions = self.vapi.nat44_ei_user_session_dump(
            self.pg5.remote_ip4, 10)
        self.assertEqual(len(sessions), 3)
        for session in sessions:
            self.assertFalse(session.flags &
                             self.config_flags.NAT44_EI_STATIC_MAPPING)
            self.assertEqual(str(session.inside_ip_address),
                             self.pg5.remote_ip4)
            self.assertEqual(session.outside_ip_address,
                             addresses[0].ip_address)
        self.assertEqual(sessions[0].protocol, IP_PROTOS.tcp)
        self.assertEqual(sessions[1].protocol, IP_PROTOS.udp)
        self.assertEqual(sessions[2].protocol, IP_PROTOS.icmp)
        self.assertEqual(sessions[0].inside_port, self.tcp_port_in)
        self.assertEqual(sessions[1].inside_port, self.udp_port_in)
        self.assertEqual(sessions[2].inside_port, self.icmp_id_in)
        self.assertEqual(sessions[0].outside_port, self.tcp_port_out)
        self.assertEqual(sessions[1].outside_port, self.udp_port_out)
        self.assertEqual(sessions[2].outside_port, self.icmp_id_out)

        # in2out 3rd interface
        pkts = self.create_stream_in(self.pg6, self.pg3)
        self.pg6.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture, static_nat_ip, True)

        # out2in 3rd interface
        pkts = self.create_stream_out(self.pg3, static_nat_ip)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg6.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg6)

        # general user and session dump verifications
        users = self.vapi.nat44_ei_user_dump()
        self.assertGreaterEqual(len(users), 3)
        addresses = self.vapi.nat44_ei_address_dump()
        self.assertEqual(len(addresses), 1)
        for user in users:
            sessions = self.vapi.nat44_ei_user_session_dump(user.ip_address,
                                                            user.vrf_id)
            for session in sessions:
                self.assertEqual(user.ip_address, session.inside_ip_address)
                self.assertTrue(session.total_bytes > session.total_pkts > 0)
                self.assertTrue(session.protocol in
                                [IP_PROTOS.tcp, IP_PROTOS.udp,
                                 IP_PROTOS.icmp])

        # pg4 session dump
        sessions = self.vapi.nat44_ei_user_session_dump(
            self.pg4.remote_ip4, 10)
        self.assertGreaterEqual(len(sessions), 4)
        for session in sessions:
            self.assertFalse(
                session.flags & self.config_flags.NAT44_EI_STATIC_MAPPING)
            self.assertEqual(str(session.inside_ip_address),
                             self.pg4.remote_ip4)
            self.assertEqual(session.outside_ip_address,
                             addresses[0].ip_address)

        # pg6 session dump
        sessions = self.vapi.nat44_ei_user_session_dump(
            self.pg6.remote_ip4, 20)
        self.assertGreaterEqual(len(sessions), 3)
        for session in sessions:
            self.assertTrue(
                session.flags & self.config_flags.NAT44_EI_STATIC_MAPPING)
            self.assertEqual(str(session.inside_ip_address),
                             self.pg6.remote_ip4)
            self.assertEqual(str(session.outside_ip_address),
                             static_nat_ip)
            self.assertTrue(session.inside_port in
                            [self.tcp_port_in, self.udp_port_in,
                             self.icmp_id_in])

    def test_hairpinning(self):
        """ NAT44EI hairpinning - 1:1 NAPT """

        host = self.pg0.remote_hosts[0]
        server = self.pg0.remote_hosts[1]
        host_in_port = 1234
        host_out_port = 0
        server_in_port = 5678
        server_out_port = 8765

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # add static mapping for server
        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
                                      server_in_port, server_out_port,
                                      proto=IP_PROTOS.tcp)

        cnt = self.statistics['/nat44-ei/hairpinning']
        # send packet from host to server
        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
             IP(src=host.ip4, dst=self.nat_addr) /
             TCP(sport=host_in_port, dport=server_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, server.ip4)
            self.assertNotEqual(tcp.sport, host_in_port)
            self.assertEqual(tcp.dport, server_in_port)
            self.assert_packet_checksums_valid(p)
            host_out_port = tcp.sport
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']
        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[:, if_idx].sum() - cnt[:, if_idx].sum(), 1)

        # send reply from server to host
        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
             IP(src=server.ip4, dst=self.nat_addr) /
             TCP(sport=server_in_port, dport=host_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, host.ip4)
            self.assertEqual(tcp.sport, server_out_port)
            self.assertEqual(tcp.dport, host_in_port)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']
        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[:, if_idx].sum() - cnt[:, if_idx].sum(),
                         2+(1 if self.vpp_worker_count > 0 else 0))

    def test_hairpinning2(self):
        """ NAT44EI hairpinning - 1:1 NAT"""

        server1_nat_ip = "10.0.0.10"
        server2_nat_ip = "10.0.0.11"
        host = self.pg0.remote_hosts[0]
        server1 = self.pg0.remote_hosts[1]
        server2 = self.pg0.remote_hosts[2]
        server_tcp_port = 22
        server_udp_port = 20

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # add static mapping for servers
        self.nat44_add_static_mapping(server1.ip4, server1_nat_ip)
        self.nat44_add_static_mapping(server2.ip4, server2_nat_ip)

        # host to server1
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             TCP(sport=self.tcp_port_in, dport=server_tcp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             UDP(sport=self.udp_port_in, dport=server_udp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             ICMP(id=self.icmp_id_in, type='echo-request'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, self.nat_addr)
                self.assertEqual(packet[IP].dst, server1.ip4)
                if packet.haslayer(TCP):
                    self.assertNotEqual(packet[TCP].sport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].dport, server_tcp_port)
                    self.tcp_port_out = packet[TCP].sport
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertNotEqual(packet[UDP].sport, self.udp_port_in)
                    self.assertEqual(packet[UDP].dport, server_udp_port)
                    self.udp_port_out = packet[UDP].sport
                else:
                    self.assertNotEqual(packet[ICMP].id, self.icmp_id_in)
                    self.icmp_id_out = packet[ICMP].id
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server1 to host
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             TCP(sport=server_tcp_port, dport=self.tcp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             UDP(sport=server_udp_port, dport=self.udp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             ICMP(id=self.icmp_id_out, type='echo-reply'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server1_nat_ip)
                self.assertEqual(packet[IP].dst, host.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].sport, server_tcp_port)
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].dport, self.udp_port_in)
                    self.assertEqual(packet[UDP].sport, server_udp_port)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server2 to server1
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             TCP(sport=self.tcp_port_in, dport=server_tcp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             UDP(sport=self.udp_port_in, dport=server_udp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             ICMP(id=self.icmp_id_in, type='echo-request'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server2_nat_ip)
                self.assertEqual(packet[IP].dst, server1.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].sport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].dport, server_tcp_port)
                    self.tcp_port_out = packet[TCP].sport
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].sport, self.udp_port_in)
                    self.assertEqual(packet[UDP].dport, server_udp_port)
                    self.udp_port_out = packet[UDP].sport
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
                    self.icmp_id_out = packet[ICMP].id
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server1 to server2
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             TCP(sport=server_tcp_port, dport=self.tcp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             UDP(sport=server_udp_port, dport=self.udp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             ICMP(id=self.icmp_id_out, type='echo-reply'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server1_nat_ip)
                self.assertEqual(packet[IP].dst, server2.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].sport, server_tcp_port)
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].dport, self.udp_port_in)
                    self.assertEqual(packet[UDP].sport, server_udp_port)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

    def test_hairpinning_avoid_inf_loop(self):
        """ NAT44EI hairpinning - 1:1 NAPT avoid infinite loop """

        host = self.pg0.remote_hosts[0]
        server = self.pg0.remote_hosts[1]
        host_in_port = 1234
        host_out_port = 0
        server_in_port = 5678
        server_out_port = 8765

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # add static mapping for server
        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
                                      server_in_port, server_out_port,
                                      proto=IP_PROTOS.tcp)

        # add another static mapping that maps pg0.local_ip4 address to itself
        self.nat44_add_static_mapping(self.pg0.local_ip4, self.pg0.local_ip4)

        # send packet from host to VPP (the packet should get dropped)
        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
             IP(src=host.ip4, dst=self.pg0.local_ip4) /
             TCP(sport=host_in_port, dport=server_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        # Here VPP used to crash due to an infinite loop

        cnt = self.statistics['/nat44-ei/hairpinning']
        # send packet from host to server
        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
             IP(src=host.ip4, dst=self.nat_addr) /
             TCP(sport=host_in_port, dport=server_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, server.ip4)
            self.assertNotEqual(tcp.sport, host_in_port)
            self.assertEqual(tcp.dport, server_in_port)
            self.assert_packet_checksums_valid(p)
            host_out_port = tcp.sport
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']
        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[:, if_idx].sum() - cnt[:, if_idx].sum(), 1)

        # send reply from server to host
        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
             IP(src=server.ip4, dst=self.nat_addr) /
             TCP(sport=server_in_port, dport=host_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, host.ip4)
            self.assertEqual(tcp.sport, server_out_port)
            self.assertEqual(tcp.dport, host_in_port)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']
        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[:, if_idx].sum() - cnt[:, if_idx].sum(),
                         2+(1 if self.vpp_worker_count > 0 else 0))

    def test_interface_addr(self):
        """ NAT44EI acquire addresses from interface """
        self.vapi.nat44_ei_add_del_interface_addr(
            is_add=1,
            sw_if_index=self.pg7.sw_if_index)

        # no address in NAT pool
        addresses = self.vapi.nat44_ei_address_dump()
        self.assertEqual(0, len(addresses))

        # configure interface address and check NAT address pool
        self.pg7.config_ip4()
        addresses = self.vapi.nat44_ei_address_dump()
        self.assertEqual(1, len(addresses))
        self.assertEqual(str(addresses[0].ip_address), self.pg7.local_ip4)

        # remove interface address and check NAT address pool
        self.pg7.unconfig_ip4()
        addresses = self.vapi.nat44_ei_address_dump()
        self.assertEqual(0, len(addresses))

    def test_interface_addr_static_mapping(self):
        """ NAT44EI Static mapping with addresses from interface """
        tag = "testTAG"

        self.vapi.nat44_ei_add_del_interface_addr(
            is_add=1,
            sw_if_index=self.pg7.sw_if_index)
        self.nat44_add_static_mapping(
            '1.2.3.4',
            external_sw_if_index=self.pg7.sw_if_index,
            tag=tag)

        # static mappings with external interface
        static_mappings = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(1, len(static_mappings))
        self.assertEqual(self.pg7.sw_if_index,
                         static_mappings[0].external_sw_if_index)
        self.assertEqual(static_mappings[0].tag, tag)

        # configure interface address and check static mappings
        self.pg7.config_ip4()
        static_mappings = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(2, len(static_mappings))
        resolved = False
        for sm in static_mappings:
            if sm.external_sw_if_index == 0xFFFFFFFF:
                self.assertEqual(str(sm.external_ip_address),
                                 self.pg7.local_ip4)
                self.assertEqual(sm.tag, tag)
                resolved = True
        self.assertTrue(resolved)

        # remove interface address and check static mappings
        self.pg7.unconfig_ip4()
        static_mappings = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(1, len(static_mappings))
        self.assertEqual(self.pg7.sw_if_index,
                         static_mappings[0].external_sw_if_index)
        self.assertEqual(static_mappings[0].tag, tag)

        # configure interface address again and check static mappings
        self.pg7.config_ip4()
        static_mappings = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(2, len(static_mappings))
        resolved = False
        for sm in static_mappings:
            if sm.external_sw_if_index == 0xFFFFFFFF:
                self.assertEqual(str(sm.external_ip_address),
                                 self.pg7.local_ip4)
                self.assertEqual(sm.tag, tag)
                resolved = True
        self.assertTrue(resolved)

        # remove static mapping
        self.nat44_add_static_mapping(
            '1.2.3.4',
            external_sw_if_index=self.pg7.sw_if_index,
            tag=tag,
            is_add=0)
        static_mappings = self.vapi.nat44_ei_static_mapping_dump()
        self.assertEqual(0, len(static_mappings))

    def test_interface_addr_identity_nat(self):
        """ NAT44EI Identity NAT with addresses from interface """

        port = 53053
        self.vapi.nat44_ei_add_del_interface_addr(
            is_add=1,
            sw_if_index=self.pg7.sw_if_index)
        self.vapi.nat44_ei_add_del_identity_mapping(
            ip_address=b'0',
            sw_if_index=self.pg7.sw_if_index,
            port=port,
            protocol=IP_PROTOS.tcp,
            is_add=1)

        # identity mappings with external interface
        identity_mappings = self.vapi.nat44_ei_identity_mapping_dump()
        self.assertEqual(1, len(identity_mappings))
        self.assertEqual(self.pg7.sw_if_index,
                         identity_mappings[0].sw_if_index)

        # configure interface address and check identity mappings
        self.pg7.config_ip4()
        identity_mappings = self.vapi.nat44_ei_identity_mapping_dump()
        resolved = False
        self.assertEqual(2, len(identity_mappings))
        for sm in identity_mappings:
            if sm.sw_if_index == 0xFFFFFFFF:
                self.assertEqual(str(identity_mappings[0].ip_address),
                                 self.pg7.local_ip4)
                self.assertEqual(port, identity_mappings[0].port)
                self.assertEqual(IP_PROTOS.tcp, identity_mappings[0].protocol)
                resolved = True
        self.assertTrue(resolved)

        # remove interface address and check identity mappings
        self.pg7.unconfig_ip4()
        identity_mappings = self.vapi.nat44_ei_identity_mapping_dump()
        self.assertEqual(1, len(identity_mappings))
        self.assertEqual(self.pg7.sw_if_index,
                         identity_mappings[0].sw_if_index)

    def test_ipfix_nat44_sess(self):
        """ NAT44EI IPFIX logging NAT44EI session created/deleted """
        self.ipfix_domain_id = 10
        self.ipfix_src_port = 20202
        collector_port = 30303
        bind_layers(UDP, IPFIX, dport=30303)
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4,
                                     src_address=self.pg3.local_ip4,
                                     path_mtu=512,
                                     template_interval=10,
                                     collector_port=collector_port)
        self.vapi.nat44_ei_ipfix_enable_disable(domain_id=self.ipfix_domain_id,
                                                src_port=self.ipfix_src_port,
                                                enable=1)

        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)
        self.nat44_add_address(self.nat_addr, is_add=0)
        self.vapi.ipfix_flush()
        capture = self.pg3.get_capture(7)
        ipfix = IPFIXDecoder()
        # first load template
        for p in capture:
            self.assertTrue(p.haslayer(IPFIX))
            self.assertEqual(p[IP].src, self.pg3.local_ip4)
            self.assertEqual(p[IP].dst, self.pg3.remote_ip4)
            self.assertEqual(p[UDP].sport, self.ipfix_src_port)
            self.assertEqual(p[UDP].dport, collector_port)
            self.assertEqual(p[IPFIX].observationDomainID,
                             self.ipfix_domain_id)
            if p.haslayer(Template):
                ipfix.add_template(p.getlayer(Template))
        # verify events in data set
        for p in capture:
            if p.haslayer(Data):
                data = ipfix.decode_data_set(p.getlayer(Set))
                self.verify_ipfix_nat44_ses(data)

    def test_ipfix_addr_exhausted(self):
        """ NAT44EI IPFIX logging NAT addresses exhausted """
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4,
                                     src_address=self.pg3.local_ip4,
                                     path_mtu=512,
                                     template_interval=10)
        self.vapi.nat44_ei_ipfix_enable_disable(domain_id=self.ipfix_domain_id,
                                                src_port=self.ipfix_src_port,
                                                enable=1)

        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             TCP(sport=3025))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.assert_nothing_captured()
        self.vapi.ipfix_flush()
        capture = self.pg3.get_capture(7)
        ipfix = IPFIXDecoder()
        # first load template
        for p in capture:
            self.assertTrue(p.haslayer(IPFIX))
            self.assertEqual(p[IP].src, self.pg3.local_ip4)
            self.assertEqual(p[IP].dst, self.pg3.remote_ip4)
            self.assertEqual(p[UDP].sport, self.ipfix_src_port)
            self.assertEqual(p[UDP].dport, 4739)
            self.assertEqual(p[IPFIX].observationDomainID,
                             self.ipfix_domain_id)
            if p.haslayer(Template):
                ipfix.add_template(p.getlayer(Template))
        # verify events in data set
        for p in capture:
            if p.haslayer(Data):
                data = ipfix.decode_data_set(p.getlayer(Set))
                self.verify_ipfix_addr_exhausted(data)

    def test_ipfix_max_sessions(self):
        """ NAT44EI IPFIX logging maximum session entries exceeded """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        max_sessions_per_thread = self.max_translations
        max_sessions = max(1, self.vpp_worker_count) * max_sessions_per_thread

        pkts = []
        for i in range(0, max_sessions):
            src = "10.10.%u.%u" % ((i & 0xFF00) >> 8, i & 0xFF)
            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
                 IP(src=src, dst=self.pg1.remote_ip4) /
                 TCP(sport=1025))
            pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()

        self.pg1.get_capture(max_sessions)
        self.vapi.set_ipfix_exporter(collector_address=self.pg3.remote_ip4,
                                     src_address=self.pg3.local_ip4,
                                     path_mtu=512,
                                     template_interval=10)
        self.vapi.nat44_ei_ipfix_enable_disable(domain_id=self.ipfix_domain_id,
                                                src_port=self.ipfix_src_port,
                                                enable=1)

        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             TCP(sport=1025))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.assert_nothing_captured()
        self.vapi.ipfix_flush()
        capture = self.pg3.get_capture(7)
        ipfix = IPFIXDecoder()
        # first load template
        for p in capture:
            self.assertTrue(p.haslayer(IPFIX))
            self.assertEqual(p[IP].src, self.pg3.local_ip4)
            self.assertEqual(p[IP].dst, self.pg3.remote_ip4)
            self.assertEqual(p[UDP].sport, self.ipfix_src_port)
            self.assertEqual(p[UDP].dport, 4739)
            self.assertEqual(p[IPFIX].observationDomainID,
                             self.ipfix_domain_id)
            if p.haslayer(Template):
                ipfix.add_template(p.getlayer(Template))
        # verify events in data set
        for p in capture:
            if p.haslayer(Data):
                data = ipfix.decode_data_set(p.getlayer(Set))
                self.verify_ipfix_max_sessions(data, max_sessions_per_thread)

    def test_syslog_apmap(self):
        """ NAT44EI syslog address and port mapping creation and deletion """
        self.vapi.syslog_set_filter(
            self.SYSLOG_SEVERITY.SYSLOG_API_SEVERITY_INFO)
        self.vapi.syslog_set_sender(self.pg3.local_ip4, self.pg3.remote_ip4)
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             TCP(sport=self.tcp_port_in, dport=20))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        self.tcp_port_out = capture[0][TCP].sport
        capture = self.pg3.get_capture(1)
        self.verify_syslog_apmap(capture[0][Raw].load)

        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.nat44_add_address(self.nat_addr, is_add=0)
        capture = self.pg3.get_capture(1)
        self.verify_syslog_apmap(capture[0][Raw].load, False)

    def test_pool_addr_fib(self):
        """ NAT44EI add pool addresses to FIB """
        static_addr = '10.0.0.10'
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr)

        # NAT44EI address
        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(op=ARP.who_has, pdst=self.nat_addr,
                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        self.assertTrue(capture[0].haslayer(ARP))
        self.assertTrue(capture[0][ARP].op, ARP.is_at)

        # 1:1 NAT address
        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(op=ARP.who_has, pdst=static_addr,
                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        self.assertTrue(capture[0].haslayer(ARP))
        self.assertTrue(capture[0][ARP].op, ARP.is_at)

        # send ARP to non-NAT44EI interface
        p = (Ether(src=self.pg2.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(op=ARP.who_has, pdst=self.nat_addr,
                 psrc=self.pg2.remote_ip4, hwsrc=self.pg2.remote_mac))
        self.pg2.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.assert_nothing_captured()

        # remove addresses and verify
        self.nat44_add_address(self.nat_addr, is_add=0)
        self.nat44_add_static_mapping(self.pg0.remote_ip4, static_addr,
                                      is_add=0)

        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(op=ARP.who_has, pdst=self.nat_addr,
                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.assert_nothing_captured()

        p = (Ether(src=self.pg1.remote_mac, dst='ff:ff:ff:ff:ff:ff') /
             ARP(op=ARP.who_has, pdst=static_addr,
                 psrc=self.pg1.remote_ip4, hwsrc=self.pg1.remote_mac))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.assert_nothing_captured()

    def test_vrf_mode(self):
        """ NAT44EI tenant VRF aware address pool mode """

        vrf_id1 = 1
        vrf_id2 = 2
        nat_ip1 = "10.0.0.10"
        nat_ip2 = "10.0.0.11"

        self.pg0.unconfig_ip4()
        self.pg1.unconfig_ip4()
        self.vapi.ip_table_add_del(is_add=1, table={'table_id': vrf_id1})
        self.vapi.ip_table_add_del(is_add=1, table={'table_id': vrf_id2})
        self.pg0.set_table_ip4(vrf_id1)
        self.pg1.set_table_ip4(vrf_id2)
        self.pg0.config_ip4()
        self.pg1.config_ip4()
        self.pg0.resolve_arp()
        self.pg1.resolve_arp()

        self.nat44_add_address(nat_ip1, vrf_id=vrf_id1)
        self.nat44_add_address(nat_ip2, vrf_id=vrf_id2)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg2.sw_if_index,
            is_add=1)

        try:
            # first VRF
            pkts = self.create_stream_in(self.pg0, self.pg2)
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg2.get_capture(len(pkts))
            self.verify_capture_out(capture, nat_ip1)

            # second VRF
            pkts = self.create_stream_in(self.pg1, self.pg2)
            self.pg1.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg2.get_capture(len(pkts))
            self.verify_capture_out(capture, nat_ip2)

        finally:
            self.pg0.unconfig_ip4()
            self.pg1.unconfig_ip4()
            self.pg0.set_table_ip4(0)
            self.pg1.set_table_ip4(0)
            self.pg0.config_ip4()
            self.pg1.config_ip4()
            self.pg0.resolve_arp()
            self.pg1.resolve_arp()
            self.vapi.ip_table_add_del(is_add=0, table={'table_id': vrf_id1})
            self.vapi.ip_table_add_del(is_add=0, table={'table_id': vrf_id2})

    def test_vrf_feature_independent(self):
        """ NAT44EI tenant VRF independent address pool mode """

        nat_ip1 = "10.0.0.10"
        nat_ip2 = "10.0.0.11"

        self.nat44_add_address(nat_ip1)
        self.nat44_add_address(nat_ip2, vrf_id=99)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg2.sw_if_index,
            is_add=1)

        # first VRF
        pkts = self.create_stream_in(self.pg0, self.pg2)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg2.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip1)

        # second VRF
        pkts = self.create_stream_in(self.pg1, self.pg2)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg2.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip1)

    def test_dynamic_ipless_interfaces(self):
        """ NAT44EI interfaces without configured IP address """
        self.create_routes_and_neigbors()
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg7.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg8.sw_if_index,
            is_add=1)

        # in2out
        pkts = self.create_stream_in(self.pg7, self.pg8)
        self.pg7.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg8.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in
        pkts = self.create_stream_out(self.pg8, self.nat_addr)
        self.pg8.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg7.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg7)

    def test_static_ipless_interfaces(self):
        """ NAT44EI interfaces without configured IP address - 1:1 NAT """

        self.create_routes_and_neigbors()
        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg7.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg8.sw_if_index,
            is_add=1)

        # out2in
        pkts = self.create_stream_out(self.pg8)
        self.pg8.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg7.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg7)

        # in2out
        pkts = self.create_stream_in(self.pg7, self.pg8)
        self.pg7.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg8.get_capture(len(pkts))
        self.verify_capture_out(capture, self.nat_addr, True)

    def test_static_with_port_ipless_interfaces(self):
        """ NAT44EI interfaces without configured IP address - 1:1 NAPT """

        self.tcp_port_out = 30606
        self.udp_port_out = 30607
        self.icmp_id_out = 30608

        self.create_routes_and_neigbors()
        self.nat44_add_address(self.nat_addr)
        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
                                      self.tcp_port_in, self.tcp_port_out,
                                      proto=IP_PROTOS.tcp)
        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
                                      self.udp_port_in, self.udp_port_out,
                                      proto=IP_PROTOS.udp)
        self.nat44_add_static_mapping(self.pg7.remote_ip4, self.nat_addr,
                                      self.icmp_id_in, self.icmp_id_out,
                                      proto=IP_PROTOS.icmp)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg7.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg8.sw_if_index,
            is_add=1)

        # out2in
        pkts = self.create_stream_out(self.pg8)
        self.pg8.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg7.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg7)

        # in2out
        pkts = self.create_stream_in(self.pg7, self.pg8)
        self.pg7.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg8.get_capture(len(pkts))
        self.verify_capture_out(capture)

    def test_static_unknown_proto(self):
        """ NAT44EI 1:1 translate packet with unknown protocol """
        nat_ip = "10.0.0.10"
        self.nat44_add_static_mapping(self.pg0.remote_ip4, nat_ip)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # in2out
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             GRE() /
             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
             TCP(sport=1234, dport=1234))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        p = self.pg1.get_capture(1)
        packet = p[0]
        try:
            self.assertEqual(packet[IP].src, nat_ip)
            self.assertEqual(packet[IP].dst, self.pg1.remote_ip4)
            self.assertEqual(packet.haslayer(GRE), 1)
            self.assert_packet_checksums_valid(packet)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", packet))
            raise

        # out2in
        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
             IP(src=self.pg1.remote_ip4, dst=nat_ip) /
             GRE() /
             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
             TCP(sport=1234, dport=1234))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        p = self.pg0.get_capture(1)
        packet = p[0]
        try:
            self.assertEqual(packet[IP].src, self.pg1.remote_ip4)
            self.assertEqual(packet[IP].dst, self.pg0.remote_ip4)
            self.assertEqual(packet.haslayer(GRE), 1)
            self.assert_packet_checksums_valid(packet)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", packet))
            raise

    def test_hairpinning_static_unknown_proto(self):
        """ NAT44EI 1:1 translate packet with unknown protocol - hairpinning
        """

        host = self.pg0.remote_hosts[0]
        server = self.pg0.remote_hosts[1]

        host_nat_ip = "10.0.0.10"
        server_nat_ip = "10.0.0.11"

        self.nat44_add_static_mapping(host.ip4, host_nat_ip)
        self.nat44_add_static_mapping(server.ip4, server_nat_ip)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # host to server
        p = (Ether(dst=self.pg0.local_mac, src=host.mac) /
             IP(src=host.ip4, dst=server_nat_ip) /
             GRE() /
             IP(src=self.pg2.remote_ip4, dst=self.pg3.remote_ip4) /
             TCP(sport=1234, dport=1234))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        p = self.pg0.get_capture(1)
        packet = p[0]
        try:
            self.assertEqual(packet[IP].src, host_nat_ip)
            self.assertEqual(packet[IP].dst, server.ip4)
            self.assertEqual(packet.haslayer(GRE), 1)
            self.assert_packet_checksums_valid(packet)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", packet))
            raise

        # server to host
        p = (Ether(dst=self.pg0.local_mac, src=server.mac) /
             IP(src=server.ip4, dst=host_nat_ip) /
             GRE() /
             IP(src=self.pg3.remote_ip4, dst=self.pg2.remote_ip4) /
             TCP(sport=1234, dport=1234))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        p = self.pg0.get_capture(1)
        packet = p[0]
        try:
            self.assertEqual(packet[IP].src, server_nat_ip)
            self.assertEqual(packet[IP].dst, host.ip4)
            self.assertEqual(packet.haslayer(GRE), 1)
            self.assert_packet_checksums_valid(packet)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", packet))
            raise

    def test_output_feature(self):
        """ NAT44EI output feature (in2out postrouting) """
        self.nat44_add_address(self.nat_addr)
        self.vapi.nat44_ei_add_del_output_interface(
            sw_if_index=self.pg3.sw_if_index, is_add=1)

        # in2out
        pkts = self.create_stream_in(self.pg0, self.pg3)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture)

        # out2in
        pkts = self.create_stream_out(self.pg3)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)

        # from non-NAT interface to NAT inside interface
        pkts = self.create_stream_in(self.pg2, self.pg0)
        self.pg2.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_no_translation(capture, self.pg2, self.pg0)

    def test_output_feature_vrf_aware(self):
        """ NAT44EI output feature VRF aware (in2out postrouting) """
        nat_ip_vrf10 = "10.0.0.10"
        nat_ip_vrf20 = "10.0.0.20"

        r1 = VppIpRoute(self, self.pg3.remote_ip4, 32,
                        [VppRoutePath(self.pg3.remote_ip4,
                                      self.pg3.sw_if_index)],
                        table_id=10)
        r2 = VppIpRoute(self, self.pg3.remote_ip4, 32,
                        [VppRoutePath(self.pg3.remote_ip4,
                                      self.pg3.sw_if_index)],
                        table_id=20)
        r1.add_vpp_config()
        r2.add_vpp_config()

        self.nat44_add_address(nat_ip_vrf10, vrf_id=10)
        self.nat44_add_address(nat_ip_vrf20, vrf_id=20)
        self.vapi.nat44_ei_add_del_output_interface(
            sw_if_index=self.pg3.sw_if_index, is_add=1)

        # in2out VRF 10
        pkts = self.create_stream_in(self.pg4, self.pg3)
        self.pg4.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip=nat_ip_vrf10)

        # out2in VRF 10
        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf10)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg4.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg4)

        # in2out VRF 20
        pkts = self.create_stream_in(self.pg6, self.pg3)
        self.pg6.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg3.get_capture(len(pkts))
        self.verify_capture_out(capture, nat_ip=nat_ip_vrf20)

        # out2in VRF 20
        pkts = self.create_stream_out(self.pg3, dst_ip=nat_ip_vrf20)
        self.pg3.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg6.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg6)

    def test_output_feature_hairpinning(self):
        """ NAT44EI output feature hairpinning (in2out postrouting) """
        host = self.pg0.remote_hosts[0]
        server = self.pg0.remote_hosts[1]
        host_in_port = 1234
        host_out_port = 0
        server_in_port = 5678
        server_out_port = 8765

        self.nat44_add_address(self.nat_addr)
        self.vapi.nat44_ei_add_del_output_interface(
            sw_if_index=self.pg0.sw_if_index, is_add=1)
        self.vapi.nat44_ei_add_del_output_interface(
            sw_if_index=self.pg1.sw_if_index, is_add=1)

        # add static mapping for server
        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
                                      server_in_port, server_out_port,
                                      proto=IP_PROTOS.tcp)

        # send packet from host to server
        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
             IP(src=host.ip4, dst=self.nat_addr) /
             TCP(sport=host_in_port, dport=server_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, server.ip4)
            self.assertNotEqual(tcp.sport, host_in_port)
            self.assertEqual(tcp.dport, server_in_port)
            self.assert_packet_checksums_valid(p)
            host_out_port = tcp.sport
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        # send reply from server to host
        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
             IP(src=server.ip4, dst=self.nat_addr) /
             TCP(sport=server_in_port, dport=host_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, host.ip4)
            self.assertEqual(tcp.sport, server_out_port)
            self.assertEqual(tcp.dport, host_in_port)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

    def test_one_armed_nat44(self):
        """ NAT44EI One armed NAT """
        remote_host = self.pg9.remote_hosts[0]
        local_host = self.pg9.remote_hosts[1]
        external_port = 0

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg9.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg9.sw_if_index,
            flags=flags, is_add=1)

        # in2out
        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
             IP(src=local_host.ip4, dst=remote_host.ip4) /
             TCP(sport=12345, dport=80))
        self.pg9.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg9.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, remote_host.ip4)
            self.assertNotEqual(tcp.sport, 12345)
            external_port = tcp.sport
            self.assertEqual(tcp.dport, 80)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        # out2in
        p = (Ether(src=self.pg9.remote_mac, dst=self.pg9.local_mac) /
             IP(src=remote_host.ip4, dst=self.nat_addr) /
             TCP(sport=80, dport=external_port))
        self.pg9.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg9.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, remote_host.ip4)
            self.assertEqual(ip.dst, local_host.ip4)
            self.assertEqual(tcp.sport, 80)
            self.assertEqual(tcp.dport, 12345)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        if self.vpp_worker_count > 1:
            node = "nat44-ei-handoff-classify"
        else:
            node = "nat44-ei-classify"

        err = self.statistics.get_err_counter('/err/%s/next in2out' % node)
        self.assertEqual(err, 1)
        err = self.statistics.get_err_counter('/err/%s/next out2in' % node)
        self.assertEqual(err, 1)

    def test_del_session(self):
        """ NAT44EI delete session """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg1.get_capture(len(pkts))

        sessions = self.vapi.nat44_ei_user_session_dump(self.pg0.remote_ip4, 0)
        nsessions = len(sessions)

        self.vapi.nat44_ei_del_session(
            address=sessions[0].inside_ip_address,
            port=sessions[0].inside_port,
            protocol=sessions[0].protocol,
            flags=self.config_flags.NAT44_EI_IF_INSIDE)

        self.vapi.nat44_ei_del_session(
            address=sessions[1].outside_ip_address,
            port=sessions[1].outside_port,
            protocol=sessions[1].protocol)

        sessions = self.vapi.nat44_ei_user_session_dump(self.pg0.remote_ip4, 0)
        self.assertEqual(nsessions - len(sessions), 2)

        self.vapi.nat44_ei_del_session(
            address=sessions[0].inside_ip_address,
            port=sessions[0].inside_port,
            protocol=sessions[0].protocol,
            flags=self.config_flags.NAT44_EI_IF_INSIDE)

        self.verify_no_nat44_user()

    def test_frag_in_order(self):
        """ NAT44EI translate fragments arriving in order """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        self.frag_in_order(proto=IP_PROTOS.tcp)
        self.frag_in_order(proto=IP_PROTOS.udp)
        self.frag_in_order(proto=IP_PROTOS.icmp)

    def test_frag_forwarding(self):
        """ NAT44EI forwarding fragment test """
        self.vapi.nat44_ei_add_del_interface_addr(
            is_add=1,
            sw_if_index=self.pg1.sw_if_index)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_forwarding_enable_disable(enable=1)

        data = b"A" * 16 + b"B" * 16 + b"C" * 3
        pkts = self.create_stream_frag(self.pg1,
                                       self.pg0.remote_ip4,
                                       4789,
                                       4789,
                                       data,
                                       proto=IP_PROTOS.udp)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        frags = self.pg0.get_capture(len(pkts))
        p = self.reass_frags_and_verify(frags,
                                        self.pg1.remote_ip4,
                                        self.pg0.remote_ip4)
        self.assertEqual(p[UDP].sport, 4789)
        self.assertEqual(p[UDP].dport, 4789)
        self.assertEqual(data, p[Raw].load)

    def test_reass_hairpinning(self):
        """ NAT44EI fragments hairpinning """

        server_addr = self.pg0.remote_hosts[1].ip4
        host_in_port = random.randint(1025, 65535)
        server_in_port = random.randint(1025, 65535)
        server_out_port = random.randint(1025, 65535)

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        # add static mapping for server
        self.nat44_add_static_mapping(server_addr, self.nat_addr,
                                      server_in_port,
                                      server_out_port,
                                      proto=IP_PROTOS.tcp)
        self.nat44_add_static_mapping(server_addr, self.nat_addr,
                                      server_in_port,
                                      server_out_port,
                                      proto=IP_PROTOS.udp)
        self.nat44_add_static_mapping(server_addr, self.nat_addr)

        self.reass_hairpinning(server_addr, server_in_port, server_out_port,
                               host_in_port, proto=IP_PROTOS.tcp)
        self.reass_hairpinning(server_addr, server_in_port, server_out_port,
                               host_in_port, proto=IP_PROTOS.udp)
        self.reass_hairpinning(server_addr, server_in_port, server_out_port,
                               host_in_port, proto=IP_PROTOS.icmp)

    def test_frag_out_of_order(self):
        """ NAT44EI translate fragments arriving out of order """

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        self.frag_out_of_order(proto=IP_PROTOS.tcp)
        self.frag_out_of_order(proto=IP_PROTOS.udp)
        self.frag_out_of_order(proto=IP_PROTOS.icmp)

    def test_port_restricted(self):
        """ NAT44EI Port restricted NAT44EI (MAP-E CE) """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_set_addr_and_port_alloc_alg(alg=1,
                                                       psid_offset=6,
                                                       psid_length=6,
                                                       psid=10)

        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             TCP(sport=4567, dport=22))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.dst, self.pg1.remote_ip4)
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(tcp.dport, 22)
            self.assertNotEqual(tcp.sport, 4567)
            self.assertEqual((tcp.sport >> 6) & 63, 10)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

    def test_port_range(self):
        """ NAT44EI External address port range """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_set_addr_and_port_alloc_alg(alg=2,
                                                       start_port=1025,
                                                       end_port=1027)

        pkts = []
        for port in range(0, 5):
            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
                 IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
                 TCP(sport=1125 + port))
            pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(3)
        for p in capture:
            tcp = p[TCP]
            self.assertGreaterEqual(tcp.sport, 1025)
            self.assertLessEqual(tcp.sport, 1027)

    def test_multiple_outside_vrf(self):
        """ NAT44EI Multiple outside VRF """
        vrf_id1 = 1
        vrf_id2 = 2

        self.pg1.unconfig_ip4()
        self.pg2.unconfig_ip4()
        self.vapi.ip_table_add_del(is_add=1, table={'table_id': vrf_id1})
        self.vapi.ip_table_add_del(is_add=1, table={'table_id': vrf_id2})
        self.pg1.set_table_ip4(vrf_id1)
        self.pg2.set_table_ip4(vrf_id2)
        self.pg1.config_ip4()
        self.pg2.config_ip4()
        self.pg1.resolve_arp()
        self.pg2.resolve_arp()

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg2.sw_if_index,
            is_add=1)

        try:
            # first VRF
            pkts = self.create_stream_in(self.pg0, self.pg1)
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg1.get_capture(len(pkts))
            self.verify_capture_out(capture, self.nat_addr)

            pkts = self.create_stream_out(self.pg1, self.nat_addr)
            self.pg1.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg0.get_capture(len(pkts))
            self.verify_capture_in(capture, self.pg0)

            self.tcp_port_in = 60303
            self.udp_port_in = 60304
            self.icmp_id_in = 60305

            # second VRF
            pkts = self.create_stream_in(self.pg0, self.pg2)
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg2.get_capture(len(pkts))
            self.verify_capture_out(capture, self.nat_addr)

            pkts = self.create_stream_out(self.pg2, self.nat_addr)
            self.pg2.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg0.get_capture(len(pkts))
            self.verify_capture_in(capture, self.pg0)

        finally:
            self.nat44_add_address(self.nat_addr, is_add=0)
            self.pg1.unconfig_ip4()
            self.pg2.unconfig_ip4()
            self.pg1.set_table_ip4(0)
            self.pg2.set_table_ip4(0)
            self.pg1.config_ip4()
            self.pg2.config_ip4()
            self.pg1.resolve_arp()
            self.pg2.resolve_arp()

    def test_mss_clamping(self):
        """ NAT44EI TCP MSS clamping """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        p = (Ether(src=self.pg0.remote_mac, dst=self.pg0.local_mac) /
             IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4) /
             TCP(sport=self.tcp_port_in, dport=self.tcp_external_port,
                 flags="S", options=[('MSS', 1400)]))

        self.vapi.nat44_ei_set_mss_clamping(enable=1, mss_value=1000)
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        # Negotiated MSS value greater than configured - changed
        self.verify_mss_value(capture[0], 1000)

        self.vapi.nat44_ei_set_mss_clamping(enable=0, mss_value=1500)
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        # MSS clamping disabled - negotiated MSS unchanged
        self.verify_mss_value(capture[0], 1400)

        self.vapi.nat44_ei_set_mss_clamping(enable=1, mss_value=1500)
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(1)
        # Negotiated MSS value smaller than configured - unchanged
        self.verify_mss_value(capture[0], 1400)

    def test_ha_send(self):
        """ NAT44EI Send HA session synchronization events (active) """
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.nat44_add_address(self.nat_addr)

        self.vapi.nat44_ei_ha_set_listener(
            ip_address=self.pg3.local_ip4, port=12345, path_mtu=512)
        self.vapi.nat44_ei_ha_set_failover(
            ip_address=self.pg3.remote_ip4, port=12346,
            session_refresh_interval=10)
        bind_layers(UDP, HANATStateSync, sport=12345)

        # create sessions
        pkts = self.create_stream_in(self.pg0, self.pg1)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out(capture)
        # active send HA events
        self.vapi.nat44_ei_ha_flush()
        stats = self.statistics['/nat44-ei/ha/add-event-send']
        self.assertEqual(stats[:, 0].sum(), 3)
        capture = self.pg3.get_capture(1)
        p = capture[0]
        self.assert_packet_checksums_valid(p)
        try:
            ip = p[IP]
            udp = p[UDP]
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(ip.src, self.pg3.local_ip4)
            self.assertEqual(ip.dst, self.pg3.remote_ip4)
            self.assertEqual(udp.sport, 12345)
            self.assertEqual(udp.dport, 12346)
            self.assertEqual(hanat.version, 1)
            # self.assertEqual(hanat.thread_index, 0)
            self.assertEqual(hanat.count, 3)
            seq = hanat.sequence_number
            for event in hanat.events:
                self.assertEqual(event.event_type, 1)
                self.assertEqual(event.in_addr, self.pg0.remote_ip4)
                self.assertEqual(event.out_addr, self.nat_addr)
                self.assertEqual(event.fib_index, 0)

        # ACK received events
        ack = (Ether(dst=self.pg3.local_mac, src=self.pg3.remote_mac) /
               IP(src=self.pg3.remote_ip4, dst=self.pg3.local_ip4) /
               UDP(sport=12346, dport=12345) /
               HANATStateSync(sequence_number=seq, flags='ACK',
                              thread_index=hanat.thread_index))
        self.pg3.add_stream(ack)
        self.pg_start()
        stats = self.statistics['/nat44-ei/ha/ack-recv']
        self.assertEqual(stats[:, 0].sum(), 1)

        # delete one session
        self.pg_enable_capture(self.pg_interfaces)
        self.vapi.nat44_ei_del_session(
            address=self.pg0.remote_ip4, port=self.tcp_port_in,
            protocol=IP_PROTOS.tcp, flags=self.config_flags.NAT44_EI_IF_INSIDE)
        self.vapi.nat44_ei_ha_flush()
        stats = self.statistics['/nat44-ei/ha/del-event-send']
        self.assertEqual(stats[:, 0].sum(), 1)
        capture = self.pg3.get_capture(1)
        p = capture[0]
        try:
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertGreater(hanat.sequence_number, seq)

        # do not send ACK, active retry send HA event again
        self.pg_enable_capture(self.pg_interfaces)
        self.virtual_sleep(12)
        stats = self.statistics['/nat44-ei/ha/retry-count']
        self.assertEqual(stats[:, 0].sum(), 3)
        stats = self.statistics['/nat44-ei/ha/missed-count']
        self.assertEqual(stats[:, 0].sum(), 1)
        capture = self.pg3.get_capture(3)
        for packet in capture:
            self.assertEqual(packet, p)

        # session counters refresh
        pkts = self.create_stream_out(self.pg1)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        self.pg0.get_capture(2)
        self.vapi.nat44_ei_ha_flush()
        stats = self.statistics['/nat44-ei/ha/refresh-event-send']
        self.assertEqual(stats[:, 0].sum(), 2)
        capture = self.pg3.get_capture(1)
        p = capture[0]
        self.assert_packet_checksums_valid(p)
        try:
            ip = p[IP]
            udp = p[UDP]
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(ip.src, self.pg3.local_ip4)
            self.assertEqual(ip.dst, self.pg3.remote_ip4)
            self.assertEqual(udp.sport, 12345)
            self.assertEqual(udp.dport, 12346)
            self.assertEqual(hanat.version, 1)
            self.assertEqual(hanat.count, 2)
            seq = hanat.sequence_number
            for event in hanat.events:
                self.assertEqual(event.event_type, 3)
                self.assertEqual(event.out_addr, self.nat_addr)
                self.assertEqual(event.fib_index, 0)
                self.assertEqual(event.total_pkts, 2)
                self.assertGreater(event.total_bytes, 0)

        stats = self.statistics['/nat44-ei/ha/ack-recv']
        ack = (Ether(dst=self.pg3.local_mac, src=self.pg3.remote_mac) /
               IP(src=self.pg3.remote_ip4, dst=self.pg3.local_ip4) /
               UDP(sport=12346, dport=12345) /
               HANATStateSync(sequence_number=seq, flags='ACK',
                              thread_index=hanat.thread_index))
        self.pg3.add_stream(ack)
        self.pg_start()
        stats = self.statistics['/nat44-ei/ha/ack-recv']
        self.assertEqual(stats[:, 0].sum(), 2)

    def test_ha_recv(self):
        """ NAT44EI Receive HA session synchronization events (passive) """
        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)
        self.vapi.nat44_ei_ha_set_listener(ip_address=self.pg3.local_ip4,
                                           port=12345, path_mtu=512)
        bind_layers(UDP, HANATStateSync, sport=12345)

        # this is a bit tricky - HA dictates thread index due to how it's
        # designed, but once we use HA to create a session, we also want
        # to pass a packet through said session. so the session must end
        # up on the correct thread from both directions - in2out (based on
        # IP address) and out2in (based on outside port)

        # first choose a thread index which is correct for IP
        thread_index = get_nat44_ei_in2out_worker_index(self.pg0.remote_ip4,
                                                        self.vpp_worker_count)

        # now pick a port which is correct for given thread
        port_per_thread = int((0xffff-1024) / max(1, self.vpp_worker_count))
        self.tcp_port_out = 1024 + random.randint(1, port_per_thread)
        self.udp_port_out = 1024 + random.randint(1, port_per_thread)
        if self.vpp_worker_count > 0:
            self.tcp_port_out += port_per_thread * (thread_index - 1)
            self.udp_port_out += port_per_thread * (thread_index - 1)

        # send HA session add events to failover/passive
        p = (Ether(dst=self.pg3.local_mac, src=self.pg3.remote_mac) /
             IP(src=self.pg3.remote_ip4, dst=self.pg3.local_ip4) /
             UDP(sport=12346, dport=12345) /
             HANATStateSync(sequence_number=1, events=[
                 Event(event_type='add', protocol='tcp',
                       in_addr=self.pg0.remote_ip4, out_addr=self.nat_addr,
                       in_port=self.tcp_port_in, out_port=self.tcp_port_out,
                       eh_addr=self.pg1.remote_ip4,
                       ehn_addr=self.pg1.remote_ip4,
                       eh_port=self.tcp_external_port,
                       ehn_port=self.tcp_external_port, fib_index=0),
                 Event(event_type='add', protocol='udp',
                       in_addr=self.pg0.remote_ip4, out_addr=self.nat_addr,
                       in_port=self.udp_port_in, out_port=self.udp_port_out,
                       eh_addr=self.pg1.remote_ip4,
                       ehn_addr=self.pg1.remote_ip4,
                       eh_port=self.udp_external_port,
                       ehn_port=self.udp_external_port, fib_index=0)],
                 thread_index=thread_index))

        self.pg3.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        # receive ACK
        capture = self.pg3.get_capture(1)
        p = capture[0]
        try:
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(hanat.sequence_number, 1)
            self.assertEqual(hanat.flags, 'ACK')
            self.assertEqual(hanat.version, 1)
            self.assertEqual(hanat.thread_index, thread_index)
        stats = self.statistics['/nat44-ei/ha/ack-send']
        self.assertEqual(stats[:, 0].sum(), 1)
        stats = self.statistics['/nat44-ei/ha/add-event-recv']
        self.assertEqual(stats[:, 0].sum(), 2)
        users = self.statistics['/nat44-ei/total-users']
        self.assertEqual(users[:, 0].sum(), 1)
        sessions = self.statistics['/nat44-ei/total-sessions']
        self.assertEqual(sessions[:, 0].sum(), 2)
        users = self.vapi.nat44_ei_user_dump()
        self.assertEqual(len(users), 1)
        self.assertEqual(str(users[0].ip_address),
                         self.pg0.remote_ip4)
        # there should be 2 sessions created by HA
        sessions = self.vapi.nat44_ei_user_session_dump(
            users[0].ip_address, users[0].vrf_id)
        self.assertEqual(len(sessions), 2)
        for session in sessions:
            self.assertEqual(str(session.inside_ip_address),
                             self.pg0.remote_ip4)
            self.assertEqual(str(session.outside_ip_address),
                             self.nat_addr)
            self.assertIn(session.inside_port,
                          [self.tcp_port_in, self.udp_port_in])
            self.assertIn(session.outside_port,
                          [self.tcp_port_out, self.udp_port_out])
            self.assertIn(session.protocol, [IP_PROTOS.tcp, IP_PROTOS.udp])

        # send HA session delete event to failover/passive
        p = (Ether(dst=self.pg3.local_mac, src=self.pg3.remote_mac) /
             IP(src=self.pg3.remote_ip4, dst=self.pg3.local_ip4) /
             UDP(sport=12346, dport=12345) /
             HANATStateSync(sequence_number=2, events=[
                 Event(event_type='del', protocol='udp',
                       in_addr=self.pg0.remote_ip4, out_addr=self.nat_addr,
                       in_port=self.udp_port_in, out_port=self.udp_port_out,
                       eh_addr=self.pg1.remote_ip4,
                       ehn_addr=self.pg1.remote_ip4,
                       eh_port=self.udp_external_port,
                       ehn_port=self.udp_external_port, fib_index=0)],
                 thread_index=thread_index))

        self.pg3.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        # receive ACK
        capture = self.pg3.get_capture(1)
        p = capture[0]
        try:
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(hanat.sequence_number, 2)
            self.assertEqual(hanat.flags, 'ACK')
            self.assertEqual(hanat.version, 1)
        users = self.vapi.nat44_ei_user_dump()
        self.assertEqual(len(users), 1)
        self.assertEqual(str(users[0].ip_address),
                         self.pg0.remote_ip4)
        # now we should have only 1 session, 1 deleted by HA
        sessions = self.vapi.nat44_ei_user_session_dump(users[0].ip_address,
                                                        users[0].vrf_id)
        self.assertEqual(len(sessions), 1)
        stats = self.statistics['/nat44-ei/ha/del-event-recv']
        self.assertEqual(stats[:, 0].sum(), 1)

        stats = self.statistics.get_err_counter(
            '/err/nat44-ei-ha/pkts-processed')
        self.assertEqual(stats, 2)

        # send HA session refresh event to failover/passive
        p = (Ether(dst=self.pg3.local_mac, src=self.pg3.remote_mac) /
             IP(src=self.pg3.remote_ip4, dst=self.pg3.local_ip4) /
             UDP(sport=12346, dport=12345) /
             HANATStateSync(sequence_number=3, events=[
                 Event(event_type='refresh', protocol='tcp',
                       in_addr=self.pg0.remote_ip4, out_addr=self.nat_addr,
                       in_port=self.tcp_port_in, out_port=self.tcp_port_out,
                       eh_addr=self.pg1.remote_ip4,
                       ehn_addr=self.pg1.remote_ip4,
                       eh_port=self.tcp_external_port,
                       ehn_port=self.tcp_external_port, fib_index=0,
                       total_bytes=1024, total_pkts=2)],
                 thread_index=thread_index))
        self.pg3.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        # receive ACK
        capture = self.pg3.get_capture(1)
        p = capture[0]
        try:
            hanat = p[HANATStateSync]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(hanat.sequence_number, 3)
            self.assertEqual(hanat.flags, 'ACK')
            self.assertEqual(hanat.version, 1)
        users = self.vapi.nat44_ei_user_dump()
        self.assertEqual(len(users), 1)
        self.assertEqual(str(users[0].ip_address),
                         self.pg0.remote_ip4)
        sessions = self.vapi.nat44_ei_user_session_dump(
            users[0].ip_address, users[0].vrf_id)
        self.assertEqual(len(sessions), 1)
        session = sessions[0]
        self.assertEqual(session.total_bytes, 1024)
        self.assertEqual(session.total_pkts, 2)
        stats = self.statistics['/nat44-ei/ha/refresh-event-recv']
        self.assertEqual(stats[:, 0].sum(), 1)

        stats = self.statistics.get_err_counter(
            '/err/nat44-ei-ha/pkts-processed')
        self.assertEqual(stats, 3)

        # send packet to test session created by HA
        p = (Ether(dst=self.pg1.local_mac, src=self.pg1.remote_mac) /
             IP(src=self.pg1.remote_ip4, dst=self.nat_addr) /
             TCP(sport=self.tcp_external_port, dport=self.tcp_port_out))
        self.pg1.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
        except IndexError:
            self.logger.error(ppp("Invalid packet:", p))
            raise
        else:
            self.assertEqual(ip.src, self.pg1.remote_ip4)
            self.assertEqual(ip.dst, self.pg0.remote_ip4)
            self.assertEqual(tcp.sport, self.tcp_external_port)
            self.assertEqual(tcp.dport, self.tcp_port_in)

    def reconfigure_frame_queue_nelts(self, frame_queue_nelts):
        self.vapi.nat44_ei_plugin_enable_disable(enable=0)
        self.vapi.nat44_ei_set_fq_options(frame_queue_nelts=frame_queue_nelts)
        # keep plugin configuration persistent
        self.plugin_enable()
        return self.vapi.nat44_ei_show_fq_options().frame_queue_nelts

    def test_set_frame_queue_nelts(self):
        """ NAT44EI API test - worker handoff frame queue elements """
        self.assertEqual(self.reconfigure_frame_queue_nelts(512), 512)

    def show_commands_at_teardown(self):
        self.logger.info(self.vapi.cli("show nat44 ei timeouts"))
        self.logger.info(self.vapi.cli("show nat44 ei addresses"))
        self.logger.info(self.vapi.cli("show nat44 ei interfaces"))
        self.logger.info(self.vapi.cli("show nat44 ei static mappings"))
        self.logger.info(self.vapi.cli("show nat44 ei interface address"))
        self.logger.info(self.vapi.cli("show nat44 ei sessions detail"))
        self.logger.info(self.vapi.cli("show nat44 ei hash tables detail"))
        self.logger.info(self.vapi.cli("show nat44 ei ha"))
        self.logger.info(
            self.vapi.cli("show nat44 ei addr-port-assignment-alg"))

    def test_outside_address_distribution(self):
        """ Outside address distribution based on source address """

        x = 100
        nat_addresses = []

        for i in range(1, x):
            a = "10.0.0.%d" % i
            nat_addresses.append(a)

        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        self.vapi.nat44_ei_add_del_address_range(
            first_ip_address=nat_addresses[0],
            last_ip_address=nat_addresses[-1],
            vrf_id=0xFFFFFFFF, is_add=1)

        self.pg0.generate_remote_hosts(x)

        pkts = []
        for i in range(x):
            info = self.create_packet_info(self.pg0, self.pg1)
            payload = self.info_to_payload(info)
            p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
                 IP(src=self.pg0.remote_hosts[i].ip4,
                     dst=self.pg1.remote_ip4) /
                 UDP(sport=7000+i, dport=8000+i) /
                 Raw(payload))
            info.data = p
            pkts.append(p)

        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        recvd = self.pg1.get_capture(len(pkts))
        for p_recvd in recvd:
            payload_info = self.payload_to_info(p_recvd[Raw])
            packet_index = payload_info.index
            info = self._packet_infos[packet_index]
            self.assertTrue(info is not None)
            self.assertEqual(packet_index, info.index)
            p_sent = info.data
            packed = socket.inet_aton(p_sent[IP].src)
            numeric = struct.unpack("!L", packed)[0]
            numeric = socket.htonl(numeric)
            a = nat_addresses[(numeric-1) % len(nat_addresses)]
            self.assertEqual(
                a, p_recvd[IP].src,
                "Invalid packet (src IP %s translated to %s, but expected %s)"
                % (p_sent[IP].src, p_recvd[IP].src, a))

    def test_default_user_sessions(self):
        """ NAT44EI default per-user session limit is used and reported """
        nat44_ei_config = self.vapi.nat44_ei_show_running_config()
        # a nonzero default should be reported for user_sessions
        self.assertNotEqual(nat44_ei_config.user_sessions, 0)


class TestNAT44Out2InDPO(MethodHolder):
    """ NAT44EI Test Cases using out2in DPO """

    @classmethod
    def setUpClass(cls):
        super(TestNAT44Out2InDPO, cls).setUpClass()
        cls.vapi.cli("set log class nat44-ei level debug")

        cls.tcp_port_in = 6303
        cls.tcp_port_out = 6303
        cls.udp_port_in = 6304
        cls.udp_port_out = 6304
        cls.icmp_id_in = 6305
        cls.icmp_id_out = 6305
        cls.nat_addr = '10.0.0.3'
        cls.dst_ip4 = '192.168.70.1'

        cls.create_pg_interfaces(range(2))

        cls.pg0.admin_up()
        cls.pg0.config_ip4()
        cls.pg0.resolve_arp()

        cls.pg1.admin_up()
        cls.pg1.config_ip6()
        cls.pg1.resolve_ndp()

        r1 = VppIpRoute(cls, "::", 0,
                        [VppRoutePath(cls.pg1.remote_ip6,
                                      cls.pg1.sw_if_index)],
                        register=False)
        r1.add_vpp_config()

    def setUp(self):
        super(TestNAT44Out2InDPO, self).setUp()
        flags = self.config_flags.NAT44_EI_OUT2IN_DPO
        self.vapi.nat44_ei_plugin_enable_disable(enable=1, flags=flags)

    def tearDown(self):
        super(TestNAT44Out2InDPO, self).tearDown()
        if not self.vpp_dead:
            self.vapi.nat44_ei_plugin_enable_disable(enable=0)
            self.vapi.cli("clear logging")

    def configure_xlat(self):
        self.dst_ip6_pfx = '1:2:3::'
        self.dst_ip6_pfx_n = socket.inet_pton(socket.AF_INET6,
                                              self.dst_ip6_pfx)
        self.dst_ip6_pfx_len = 96
        self.src_ip6_pfx = '4:5:6::'
        self.src_ip6_pfx_n = socket.inet_pton(socket.AF_INET6,
                                              self.src_ip6_pfx)
        self.src_ip6_pfx_len = 96
        self.vapi.map_add_domain(self.dst_ip6_pfx_n, self.dst_ip6_pfx_len,
                                 self.src_ip6_pfx_n, self.src_ip6_pfx_len,
                                 '\x00\x00\x00\x00', 0)

    @unittest.skip('Temporary disabled')
    def test_464xlat_ce(self):
        """ Test 464XLAT CE with NAT44EI """

        self.configure_xlat()

        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_add_del_address_range(
            first_ip_address=self.nat_addr_n,
            last_ip_address=self.nat_addr_n,
            vrf_id=0xFFFFFFFF, is_add=1)

        out_src_ip6 = self.compose_ip6(self.dst_ip4, self.dst_ip6_pfx,
                                       self.dst_ip6_pfx_len)
        out_dst_ip6 = self.compose_ip6(self.nat_addr, self.src_ip6_pfx,
                                       self.src_ip6_pfx_len)

        try:
            pkts = self.create_stream_in(self.pg0, self.pg1, self.dst_ip4)
            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg1.get_capture(len(pkts))
            self.verify_capture_out_ip6(capture, nat_ip=out_dst_ip6,
                                        dst_ip=out_src_ip6)

            pkts = self.create_stream_out_ip6(self.pg1, out_src_ip6,
                                              out_dst_ip6)
            self.pg1.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            capture = self.pg0.get_capture(len(pkts))
            self.verify_capture_in(capture, self.pg0)
        finally:
            self.vapi.nat44_ei_interface_add_del_feature(
                sw_if_index=self.pg0.sw_if_index,
                flags=flags)
            self.vapi.nat44_ei_add_del_address_range(
                first_ip_address=self.nat_addr_n,
                last_ip_address=self.nat_addr_n,
                vrf_id=0xFFFFFFFF)

    @unittest.skip('Temporary disabled')
    def test_464xlat_ce_no_nat(self):
        """ Test 464XLAT CE without NAT44EI """

        self.configure_xlat()

        out_src_ip6 = self.compose_ip6(self.dst_ip4, self.dst_ip6_pfx,
                                       self.dst_ip6_pfx_len)
        out_dst_ip6 = self.compose_ip6(self.pg0.remote_ip4, self.src_ip6_pfx,
                                       self.src_ip6_pfx_len)

        pkts = self.create_stream_in(self.pg0, self.pg1, self.dst_ip4)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg1.get_capture(len(pkts))
        self.verify_capture_out_ip6(capture, dst_ip=out_src_ip6,
                                    nat_ip=out_dst_ip6, same_port=True)

        pkts = self.create_stream_out_ip6(self.pg1, out_src_ip6, out_dst_ip6)
        self.pg1.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        self.verify_capture_in(capture, self.pg0)


class TestNAT44EIMW(MethodHolder):
    """ NAT44EI Test Cases (multiple workers) """
    vpp_worker_count = 2
    max_translations = 10240
    max_users = 10240

    @classmethod
    def setUpClass(cls):
        super(TestNAT44EIMW, cls).setUpClass()
        cls.vapi.cli("set log class nat level debug")

        cls.tcp_port_in = 6303
        cls.tcp_port_out = 6303
        cls.udp_port_in = 6304
        cls.udp_port_out = 6304
        cls.icmp_id_in = 6305
        cls.icmp_id_out = 6305
        cls.nat_addr = '10.0.0.3'
        cls.ipfix_src_port = 4739
        cls.ipfix_domain_id = 1
        cls.tcp_external_port = 80
        cls.udp_external_port = 69

        cls.create_pg_interfaces(range(10))
        cls.interfaces = list(cls.pg_interfaces[0:4])

        for i in cls.interfaces:
            i.admin_up()
            i.config_ip4()
            i.resolve_arp()

        cls.pg0.generate_remote_hosts(3)
        cls.pg0.configure_ipv4_neighbors()

        cls.pg1.generate_remote_hosts(1)
        cls.pg1.configure_ipv4_neighbors()

        cls.overlapping_interfaces = list(list(cls.pg_interfaces[4:7]))
        cls.vapi.ip_table_add_del(is_add=1, table={'table_id': 10})
        cls.vapi.ip_table_add_del(is_add=1, table={'table_id': 20})

        cls.pg4._local_ip4 = "172.16.255.1"
        cls.pg4._remote_hosts[0]._ip4 = "172.16.255.2"
        cls.pg4.set_table_ip4(10)
        cls.pg5._local_ip4 = "172.17.255.3"
        cls.pg5._remote_hosts[0]._ip4 = "172.17.255.4"
        cls.pg5.set_table_ip4(10)
        cls.pg6._local_ip4 = "172.16.255.1"
        cls.pg6._remote_hosts[0]._ip4 = "172.16.255.2"
        cls.pg6.set_table_ip4(20)
        for i in cls.overlapping_interfaces:
            i.config_ip4()
            i.admin_up()
            i.resolve_arp()

        cls.pg7.admin_up()
        cls.pg8.admin_up()

        cls.pg9.generate_remote_hosts(2)
        cls.pg9.config_ip4()
        cls.vapi.sw_interface_add_del_address(
            sw_if_index=cls.pg9.sw_if_index,
            prefix="10.0.0.1/24")

        cls.pg9.admin_up()
        cls.pg9.resolve_arp()
        cls.pg9._remote_hosts[1]._ip4 = cls.pg9._remote_hosts[0]._ip4
        cls.pg4._remote_ip4 = cls.pg9._remote_hosts[0]._ip4 = "10.0.0.2"
        cls.pg9.resolve_arp()

    def setUp(self):
        super(TestNAT44EIMW, self).setUp()
        self.vapi.nat44_ei_plugin_enable_disable(
            sessions=self.max_translations,
            users=self.max_users, enable=1)

    def tearDown(self):
        super(TestNAT44EIMW, self).tearDown()
        if not self.vpp_dead:
            self.vapi.nat44_ei_ipfix_enable_disable(
                domain_id=self.ipfix_domain_id,
                src_port=self.ipfix_src_port,
                enable=0)
            self.ipfix_src_port = 4739
            self.ipfix_domain_id = 1

            self.vapi.nat44_ei_plugin_enable_disable(enable=0)
            self.vapi.cli("clear logging")

    def test_hairpinning(self):
        """ NAT44EI hairpinning - 1:1 NAPT """

        host = self.pg0.remote_hosts[0]
        server = self.pg0.remote_hosts[1]
        host_in_port = 1234
        host_out_port = 0
        server_in_port = 5678
        server_out_port = 8765
        worker_1 = 1
        worker_2 = 2

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # add static mapping for server
        self.nat44_add_static_mapping(server.ip4, self.nat_addr,
                                      server_in_port, server_out_port,
                                      proto=IP_PROTOS.tcp)

        cnt = self.statistics['/nat44-ei/hairpinning']
        # send packet from host to server
        p = (Ether(src=host.mac, dst=self.pg0.local_mac) /
             IP(src=host.ip4, dst=self.nat_addr) /
             TCP(sport=host_in_port, dport=server_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, server.ip4)
            self.assertNotEqual(tcp.sport, host_in_port)
            self.assertEqual(tcp.dport, server_in_port)
            self.assert_packet_checksums_valid(p)
            host_out_port = tcp.sport
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']

        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[worker_2][if_idx] - cnt[worker_1][if_idx], 1)

        # send reply from server to host
        p = (Ether(src=server.mac, dst=self.pg0.local_mac) /
             IP(src=server.ip4, dst=self.nat_addr) /
             TCP(sport=server_in_port, dport=host_out_port))
        self.pg0.add_stream(p)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(1)
        p = capture[0]
        try:
            ip = p[IP]
            tcp = p[TCP]
            self.assertEqual(ip.src, self.nat_addr)
            self.assertEqual(ip.dst, host.ip4)
            self.assertEqual(tcp.sport, server_out_port)
            self.assertEqual(tcp.dport, host_in_port)
            self.assert_packet_checksums_valid(p)
        except:
            self.logger.error(ppp("Unexpected or invalid packet:", p))
            raise

        after = self.statistics['/nat44-ei/hairpinning']
        if_idx = self.pg0.sw_if_index
        self.assertEqual(after[worker_1][if_idx] - cnt[worker_1][if_idx], 1)
        self.assertEqual(after[worker_2][if_idx] - cnt[worker_2][if_idx], 2)

    def test_hairpinning2(self):
        """ NAT44EI hairpinning - 1:1 NAT"""

        server1_nat_ip = "10.0.0.10"
        server2_nat_ip = "10.0.0.11"
        host = self.pg0.remote_hosts[0]
        server1 = self.pg0.remote_hosts[1]
        server2 = self.pg0.remote_hosts[2]
        server_tcp_port = 22
        server_udp_port = 20

        self.nat44_add_address(self.nat_addr)
        flags = self.config_flags.NAT44_EI_IF_INSIDE
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg0.sw_if_index,
            flags=flags, is_add=1)
        self.vapi.nat44_ei_interface_add_del_feature(
            sw_if_index=self.pg1.sw_if_index,
            is_add=1)

        # add static mapping for servers
        self.nat44_add_static_mapping(server1.ip4, server1_nat_ip)
        self.nat44_add_static_mapping(server2.ip4, server2_nat_ip)

        # host to server1
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             TCP(sport=self.tcp_port_in, dport=server_tcp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             UDP(sport=self.udp_port_in, dport=server_udp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=host.ip4, dst=server1_nat_ip) /
             ICMP(id=self.icmp_id_in, type='echo-request'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, self.nat_addr)
                self.assertEqual(packet[IP].dst, server1.ip4)
                if packet.haslayer(TCP):
                    self.assertNotEqual(packet[TCP].sport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].dport, server_tcp_port)
                    self.tcp_port_out = packet[TCP].sport
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertNotEqual(packet[UDP].sport, self.udp_port_in)
                    self.assertEqual(packet[UDP].dport, server_udp_port)
                    self.udp_port_out = packet[UDP].sport
                else:
                    self.assertNotEqual(packet[ICMP].id, self.icmp_id_in)
                    self.icmp_id_out = packet[ICMP].id
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server1 to host
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             TCP(sport=server_tcp_port, dport=self.tcp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             UDP(sport=server_udp_port, dport=self.udp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=self.nat_addr) /
             ICMP(id=self.icmp_id_out, type='echo-reply'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server1_nat_ip)
                self.assertEqual(packet[IP].dst, host.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].sport, server_tcp_port)
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].dport, self.udp_port_in)
                    self.assertEqual(packet[UDP].sport, server_udp_port)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server2 to server1
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             TCP(sport=self.tcp_port_in, dport=server_tcp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             UDP(sport=self.udp_port_in, dport=server_udp_port))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server2.ip4, dst=server1_nat_ip) /
             ICMP(id=self.icmp_id_in, type='echo-request'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server2_nat_ip)
                self.assertEqual(packet[IP].dst, server1.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].sport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].dport, server_tcp_port)
                    self.tcp_port_out = packet[TCP].sport
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].sport, self.udp_port_in)
                    self.assertEqual(packet[UDP].dport, server_udp_port)
                    self.udp_port_out = packet[UDP].sport
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
                    self.icmp_id_out = packet[ICMP].id
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise

        # server1 to server2
        pkts = []
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             TCP(sport=server_tcp_port, dport=self.tcp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             UDP(sport=server_udp_port, dport=self.udp_port_out))
        pkts.append(p)
        p = (Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac) /
             IP(src=server1.ip4, dst=server2_nat_ip) /
             ICMP(id=self.icmp_id_out, type='echo-reply'))
        pkts.append(p)
        self.pg0.add_stream(pkts)
        self.pg_enable_capture(self.pg_interfaces)
        self.pg_start()
        capture = self.pg0.get_capture(len(pkts))
        for packet in capture:
            try:
                self.assertEqual(packet[IP].src, server1_nat_ip)
                self.assertEqual(packet[IP].dst, server2.ip4)
                if packet.haslayer(TCP):
                    self.assertEqual(packet[TCP].dport, self.tcp_port_in)
                    self.assertEqual(packet[TCP].sport, server_tcp_port)
                    self.assert_packet_checksums_valid(packet)
                elif packet.haslayer(UDP):
                    self.assertEqual(packet[UDP].dport, self.udp_port_in)
                    self.assertEqual(packet[UDP].sport, server_udp_port)
                else:
                    self.assertEqual(packet[ICMP].id, self.icmp_id_in)
            except:
                self.logger.error(ppp("Unexpected or invalid packet:", packet))
                raise


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