nat: refactor & MW support for NAT tests

Split ED and EI nat44 test cases. Added multi worker
support for ED test cases.

Type: refactor

Change-Id: Ibcc2f62b94cacff69ed35c5d914b55f9fdbcf882
Signed-off-by: Filip Varga <fivarga@cisco.com>

1 files changed, 3836 insertions, 0 deletions

diff --git a/src/plugins/nat/test/test_nat44_ei.py b/src/plugins/nat/test/test_nat44_ei.py
new file mode 100644
index 00000000000..16a3376e9b2
--- /dev/null
+++ b/src/plugins/nat/test/test_nat44_ei.py
@@ -0,0 +1,3836 @@
+#!/usr/bin/env python3
+
+import ipaddress
+import random
+import socket
+import struct
+import unittest
+from io import BytesIO
+from time import sleep
+
+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_nat_config_flags_t
+
+    @property
+    def nat44_config_flags(self):
+        return VppEnum.vl_api_nat44_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.NAT_IS_ADDR_ONLY
+
+        self.vapi.nat44_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, twice_nat=0):
+        """
+        Add/delete NAT44EI address
+
+        :param ip: IP address
+        :param is_add: 1 if add, 0 if delete (Default add)
+        :param twice_nat: twice NAT address for external hosts
+        """
+        flags = self.config_flags.NAT_IS_TWICE_NAT if twice_nat else 0
+        self.vapi.nat44_add_del_address_range(first_ip_address=ip,
+                                              last_ip_address=ip,
+                                              vrf_id=vrf_id,
+                                              is_add=is_add,
+                                              flags=flags)
+
+    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("Invalid protocol")
+        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_user_dump()
+        self.assertEqual(len(users), 0)
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 0)
+        sessions = self.statistics.get_counter('/nat44/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)
+
+
+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 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(TestNAT44EI, self).setUp()
+        self.vapi.nat44_plugin_enable_disable(
+            sessions=self.max_translations,
+            users=self.max_users, enable=1)
+
+    def tearDown(self):
+        super(TestNAT44EI, self).tearDown()
+        if not self.vpp_dead:
+            self.vapi.nat_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_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(0, nat_config.endpoint_dependent)
+
+        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.get_counter('/nat44/total-sessions')
+        self.assertTrue(sessions[0][0] > 0)
+        self.logger.info("sessions before clearing: %s" % sessions[0][0])
+
+        self.vapi.cli("clear nat44 sessions")
+
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 0)
+        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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+
+        # in2out
+        tcpn = self.statistics.get_counter('/nat44/in2out/slowpath/tcp')[0]
+        udpn = self.statistics.get_counter('/nat44/in2out/slowpath/udp')[0]
+        icmpn = self.statistics.get_counter('/nat44/in2out/slowpath/icmp')[0]
+        drops = self.statistics.get_counter('/nat44/in2out/slowpath/drops')[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)
+
+        if_idx = self.pg0.sw_if_index
+        cnt = self.statistics.get_counter('/nat44/in2out/slowpath/tcp')[0]
+        self.assertEqual(cnt[if_idx] - tcpn[if_idx], 2)
+        cnt = self.statistics.get_counter('/nat44/in2out/slowpath/udp')[0]
+        self.assertEqual(cnt[if_idx] - udpn[if_idx], 1)
+        cnt = self.statistics.get_counter('/nat44/in2out/slowpath/icmp')[0]
+        self.assertEqual(cnt[if_idx] - icmpn[if_idx], 1)
+        cnt = self.statistics.get_counter('/nat44/in2out/slowpath/drops')[0]
+        self.assertEqual(cnt[if_idx] - drops[if_idx], 0)
+
+        # out2in
+        tcpn = self.statistics.get_counter('/nat44/out2in/slowpath/tcp')[0]
+        udpn = self.statistics.get_counter('/nat44/out2in/slowpath/udp')[0]
+        icmpn = self.statistics.get_counter('/nat44/out2in/slowpath/icmp')[0]
+        drops = self.statistics.get_counter('/nat44/out2in/slowpath/drops')[0]
+
+        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.get_counter('/nat44/out2in/slowpath/tcp')[0]
+        self.assertEqual(cnt[if_idx] - tcpn[if_idx], 2)
+        cnt = self.statistics.get_counter('/nat44/out2in/slowpath/udp')[0]
+        self.assertEqual(cnt[if_idx] - udpn[if_idx], 1)
+        cnt = self.statistics.get_counter('/nat44/out2in/slowpath/icmp')[0]
+        self.assertEqual(cnt[if_idx] - icmpn[if_idx], 1)
+        cnt = self.statistics.get_counter('/nat44/out2in/slowpath/drops')[0]
+        self.assertEqual(cnt[if_idx] - drops[if_idx], 0)
+
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 1)
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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)
+        self.pg0.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_1(self):
+        """ NAT44EI handling of server packets with TTL=1 """
+
+        self.nat44_add_address(self.nat_addr)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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)
+        self.pg1.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,
+                                                 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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_forwarding_enable_disable(enable=1)
+
+        real_ip = self.pg0.remote_ip4
+        alias_ip = self.nat_addr
+        flags = self.config_flags.NAT_IS_ADDR_ONLY
+        self.vapi.nat44_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_forwarding_enable_disable(enable=0)
+            flags = self.config_flags.NAT_IS_ADDR_ONLY
+            self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        sm = self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        sm = self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg3.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_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.NAT_IS_ADDR_ONLY
+        self.vapi.nat44_add_del_identity_mapping(
+            ip_address=self.pg0.remote_ip4, sw_if_index=0xFFFFFFFF,
+            flags=flags, is_add=1)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_user_session_dump(self.pg0.remote_ip4, 0)
+        self.assertEqual(len(sessions), 0)
+        flags = self.config_flags.NAT_IS_ADDR_ONLY
+        self.vapi.nat44_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_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg3.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg4.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg5.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_address_dump()
+        self.assertEqual(len(addresses), 1)
+        sessions = self.vapi.nat44_user_session_dump(self.pg5.remote_ip4, 10)
+        self.assertEqual(len(sessions), 3)
+        for session in sessions:
+            self.assertFalse(session.flags & self.config_flags.NAT_IS_STATIC)
+            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_user_dump()
+        self.assertGreaterEqual(len(users), 3)
+        addresses = self.vapi.nat44_address_dump()
+        self.assertEqual(len(addresses), 1)
+        for user in users:
+            sessions = self.vapi.nat44_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])
+                self.assertFalse(session.flags &
+                                 self.config_flags.NAT_IS_EXT_HOST_VALID)
+
+        # pg4 session dump
+        sessions = self.vapi.nat44_user_session_dump(self.pg4.remote_ip4, 10)
+        self.assertGreaterEqual(len(sessions), 4)
+        for session in sessions:
+            self.assertFalse(session.flags & self.config_flags.NAT_IS_STATIC)
+            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_user_session_dump(self.pg6.remote_ip4, 20)
+        self.assertGreaterEqual(len(sessions), 3)
+        for session in sessions:
+            self.assertTrue(session.flags & self.config_flags.NAT_IS_STATIC)
+            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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.get_counter('/nat44/hairpinning')[0]
+        # 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.get_counter('/nat44/hairpinning')[0]
+        if_idx = self.pg0.sw_if_index
+        self.assertEqual(after[if_idx] - cnt[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.get_counter('/nat44/hairpinning')[0]
+        if_idx = self.pg0.sw_if_index
+        self.assertEqual(after[if_idx] - cnt[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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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):
+        """ NAT44 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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.get_counter('/nat44/hairpinning')[0]
+        # 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.get_counter('/nat44/hairpinning')[0]
+        if_idx = self.pg0.sw_if_index
+        self.assertEqual(after[if_idx] - cnt[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.get_counter('/nat44/hairpinning')[0]
+        if_idx = self.pg0.sw_if_index
+        self.assertEqual(after[if_idx] - cnt[if_idx], 2)
+
+    def test_interface_addr(self):
+        """ NAT44EI acquire addresses from interface """
+        self.vapi.nat44_add_del_interface_addr(
+            is_add=1,
+            sw_if_index=self.pg7.sw_if_index)
+
+        # no address in NAT pool
+        addresses = self.vapi.nat44_address_dump()
+        self.assertEqual(0, len(addresses))
+
+        # configure interface address and check NAT address pool
+        self.pg7.config_ip4()
+        addresses = self.vapi.nat44_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_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_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_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_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_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_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_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_add_del_interface_addr(
+            is_add=1,
+            sw_if_index=self.pg7.sw_if_index)
+        self.vapi.nat44_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_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_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_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.nat_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.nat_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()
+        sleep(1)
+        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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+
+        max_sessions = self.max_translations
+
+        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.nat_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()
+        sleep(1)
+        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)
+
+    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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg7.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg7.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg7.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1, flags=flags,
+            sw_if_index=self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1, flags=flags,
+            sw_if_index=self.pg1.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1,
+            sw_if_index=self.pg3.sw_if_index)
+
+        # 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)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1, flags=flags,
+            sw_if_index=self.pg4.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1, flags=flags,
+            sw_if_index=self.pg6.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1,
+            sw_if_index=self.pg3.sw_if_index)
+
+        # 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)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1, flags=flags,
+            sw_if_index=self.pg0.sw_if_index)
+        self.vapi.nat44_interface_add_del_output_feature(
+            is_add=1,
+            sw_if_index=self.pg1.sw_if_index)
+
+        # 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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg9.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_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
+
+        err = self.statistics.get_err_counter(
+            '/err/nat44-classify/next in2out')
+        self.assertEqual(err, 1)
+        err = self.statistics.get_err_counter(
+            '/err/nat44-classify/next out2in')
+        self.assertEqual(err, 1)
+
+    def test_del_session(self):
+        """ NAT44EI delete session """
+        self.nat44_add_address(self.nat_addr)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_user_session_dump(self.pg0.remote_ip4, 0)
+        nsessions = len(sessions)
+
+        self.vapi.nat44_del_session(address=sessions[0].inside_ip_address,
+                                    port=sessions[0].inside_port,
+                                    protocol=sessions[0].protocol,
+                                    flags=self.config_flags.NAT_IS_INSIDE)
+        self.vapi.nat44_del_session(address=sessions[1].outside_ip_address,
+                                    port=sessions[1].outside_port,
+                                    protocol=sessions[1].protocol)
+
+        sessions = self.vapi.nat44_user_session_dump(self.pg0.remote_ip4, 0)
+        self.assertEqual(nsessions - len(sessions), 2)
+
+        self.vapi.nat44_del_session(address=sessions[0].inside_ip_address,
+                                    port=sessions[0].inside_port,
+                                    protocol=sessions[0].protocol,
+                                    flags=self.config_flags.NAT_IS_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_add_del_interface_addr(
+            is_add=1,
+            sw_if_index=self.pg1.sw_if_index)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat44_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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.nat_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.nat_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.nat_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.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.nat44_add_address(self.nat_addr)
+
+        self.vapi.nat_ha_set_listener(ip_address=self.pg3.local_ip4,
+                                      port=12345,
+                                      path_mtu=512)
+        self.vapi.nat_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.nat_ha_flush()
+        stats = self.statistics.get_counter('/nat44/ha/add-event-send')
+        self.assertEqual(stats[0][0], 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'))
+        self.pg3.add_stream(ack)
+        self.pg_start()
+        stats = self.statistics.get_counter('/nat44/ha/ack-recv')
+        self.assertEqual(stats[0][0], 1)
+
+        # delete one session
+        self.pg_enable_capture(self.pg_interfaces)
+        self.vapi.nat44_del_session(address=self.pg0.remote_ip4,
+                                    port=self.tcp_port_in,
+                                    protocol=IP_PROTOS.tcp,
+                                    flags=self.config_flags.NAT_IS_INSIDE)
+        self.vapi.nat_ha_flush()
+        stats = self.statistics.get_counter('/nat44/ha/del-event-send')
+        self.assertEqual(stats[0][0], 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)
+        sleep(12)
+        stats = self.statistics.get_counter('/nat44/ha/retry-count')
+        self.assertEqual(stats[0][0], 3)
+        stats = self.statistics.get_counter('/nat44/ha/missed-count')
+        self.assertEqual(stats[0][0], 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.nat_ha_flush()
+        stats = self.statistics.get_counter('/nat44/ha/refresh-event-send')
+        self.assertEqual(stats[0][0], 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)
+
+        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'))
+        self.pg3.add_stream(ack)
+        self.pg_start()
+        stats = self.statistics.get_counter('/nat44/ha/ack-recv')
+        self.assertEqual(stats[0][0], 2)
+
+    def test_ha_recv(self):
+        """ NAT44EI Receive HA session synchronization events (passive) """
+        self.nat44_add_address(self.nat_addr)
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg1.sw_if_index,
+            is_add=1)
+        self.vapi.nat_ha_set_listener(ip_address=self.pg3.local_ip4,
+                                      port=12345,
+                                      path_mtu=512)
+        bind_layers(UDP, HANATStateSync, sport=12345)
+
+        self.tcp_port_out = random.randint(1025, 65535)
+        self.udp_port_out = random.randint(1025, 65535)
+
+        # 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)]))
+
+        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, 0)
+        stats = self.statistics.get_counter('/nat44/ha/ack-send')
+        self.assertEqual(stats[0][0], 1)
+        stats = self.statistics.get_counter('/nat44/ha/add-event-recv')
+        self.assertEqual(stats[0][0], 2)
+        users = self.statistics.get_counter('/nat44/total-users')
+        self.assertEqual(users[0][0], 1)
+        sessions = self.statistics.get_counter('/nat44/total-sessions')
+        self.assertEqual(sessions[0][0], 2)
+        users = self.vapi.nat44_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_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)]))
+
+        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_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_user_session_dump(users[0].ip_address,
+                                                     users[0].vrf_id)
+        self.assertEqual(len(sessions), 1)
+        stats = self.statistics.get_counter('/nat44/ha/del-event-recv')
+        self.assertEqual(stats[0][0], 1)
+
+        stats = self.statistics.get_err_counter('/err/nat-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)]))
+        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_user_dump()
+        self.assertEqual(len(users), 1)
+        self.assertEqual(str(users[0].ip_address),
+                         self.pg0.remote_ip4)
+        sessions = self.vapi.nat44_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.get_counter('/nat44/ha/refresh-event-recv')
+        self.assertEqual(stats[0][0], 1)
+
+        stats = self.statistics.get_err_counter('/err/nat-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 show_commands_at_teardown(self):
+        self.logger.info(self.vapi.cli("show nat44 addresses"))
+        self.logger.info(self.vapi.cli("show nat44 interfaces"))
+        self.logger.info(self.vapi.cli("show nat44 static mappings"))
+        self.logger.info(self.vapi.cli("show nat44 interface address"))
+        self.logger.info(self.vapi.cli("show nat44 sessions detail"))
+        self.logger.info(self.vapi.cli("show nat44 hash tables detail"))
+        self.logger.info(self.vapi.cli("show nat timeouts"))
+        self.logger.info(
+            self.vapi.cli("show nat addr-port-assignment-alg"))
+        self.logger.info(self.vapi.cli("show nat ha"))
+
+
+class TestNAT44Out2InDPO(MethodHolder):
+    """ NAT44EI Test Cases using out2in DPO """
+
+    @classmethod
+    def setUpClass(cls):
+        super(TestNAT44Out2InDPO, 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.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.nat44_config_flags.NAT44_API_IS_OUT2IN_DPO
+        self.vapi.nat44_plugin_enable_disable(enable=1, flags=flags)
+
+    def tearDown(self):
+        super(TestNAT44Out2InDPO, self).tearDown()
+        if not self.vpp_dead:
+            self.vapi.nat44_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 """
+
+        nat_config = self.vapi.nat_show_config()
+        self.assertEqual(1, nat_config.out2in_dpo)
+
+        self.configure_xlat()
+
+        flags = self.config_flags.NAT_IS_INSIDE
+        self.vapi.nat44_interface_add_del_feature(
+            sw_if_index=self.pg0.sw_if_index,
+            flags=flags, is_add=1)
+        self.vapi.nat44_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_interface_add_del_feature(
+                sw_if_index=self.pg0.sw_if_index,
+                flags=flags)
+            self.vapi.nat44_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)
+
+
+if __name__ == '__main__':
+    unittest.main(testRunner=VppTestRunner)