import socket

import scapy.compat
from scapy.layers.inet import IP, UDP
from scapy.layers.inet6 import IPv6
from scapy.layers.l2 import Ether, GRE
from scapy.packet import Raw
from scapy.data import IP_PROTOS

from framework import VppTestCase
from util import ppp
from vpp_ip_route import VppIpRoute, VppRoutePath
from vpp_ip import INVALID_INDEX
from config import config
import unittest

""" TestLB is a subclass of  VPPTestCase classes.

 TestLB class defines Load Balancer test cases for:
  - IP4 to GRE4 encap on per-port vip case
  - IP4 to GRE6 encap on per-port vip case
  - IP6 to GRE4 encap on per-port vip case
  - IP6 to GRE6 encap on per-port vip case
  - IP4 to L3DSR encap on vip case
  - IP4 to L3DSR encap on per-port vip case
  - IP4 to L3DSR encap on per-port vip with src_ip_sticky case
  - IP4 to NAT4 encap on per-port vip case
  - IP6 to NAT6 encap on per-port vip case

 As stated in comments below, GRE has issues with IPv6.
 All test cases involving IPv6 are executed, but
 received packets are not parsed and checked.

"""


@unittest.skipIf("lb" in config.excluded_plugins, "Exclude LB plugin tests")
class TestLB(VppTestCase):
    """Load Balancer Test Case"""

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

        cls.ass = range(5)
        cls.packets = range(100)

        try:
            cls.create_pg_interfaces(range(2))
            cls.interfaces = list(cls.pg_interfaces)

            for i in cls.interfaces:
                i.admin_up()
                i.config_ip4()
                i.config_ip6()
                i.disable_ipv6_ra()
                i.resolve_arp()
                i.resolve_ndp()

            dst4 = VppIpRoute(
                cls,
                "10.0.0.0",
                24,
                [VppRoutePath(cls.pg1.remote_ip4, INVALID_INDEX)],
                register=False,
            )
            dst4.add_vpp_config()
            dst6 = VppIpRoute(
                cls,
                "2002::",
                16,
                [VppRoutePath(cls.pg1.remote_ip6, INVALID_INDEX)],
                register=False,
            )
            dst6.add_vpp_config()
            cls.vapi.lb_conf(ip4_src_address="39.40.41.42", ip6_src_address="2004::1")
        except Exception:
            super(TestLB, cls).tearDownClass()
            raise

    @classmethod
    def tearDownClass(cls):
        super(TestLB, cls).tearDownClass()

    def tearDown(self):
        super(TestLB, self).tearDown()

    def show_commands_at_teardown(self):
        self.logger.info(self.vapi.cli("show lb vip verbose"))

    def getIPv4Flow(self, id):
        return IP(
            dst="90.0.%u.%u" % (id / 255, id % 255),
            src="40.0.%u.%u" % (id / 255, id % 255),
        ) / UDP(sport=10000 + id, dport=20000)

    def getIPv6Flow(self, id):
        return IPv6(dst="2001::%u" % (id), src="fd00:f00d:ffff::%u" % (id)) / UDP(
            sport=10000 + id, dport=20000
        )

    def generatePackets(self, src_if, isv4):
        self.reset_packet_infos()
        pkts = []
        for pktid in self.packets:
            info = self.create_packet_info(src_if, self.pg1)
            payload = self.info_to_payload(info)
            ip = self.getIPv4Flow(pktid) if isv4 else self.getIPv6Flow(pktid)
            packet = (
                Ether(dst=src_if.local_mac, src=src_if.remote_mac) / ip / Raw(payload)
            )
            self.extend_packet(packet, 128)
            info.data = packet.copy()
            pkts.append(packet)
        return pkts

    def checkInner(self, gre, isv4):
        IPver = IP if isv4 else IPv6
        self.assertEqual(gre.proto, 0x0800 if isv4 else 0x86DD)
        self.assertEqual(gre.flags, 0)
        self.assertEqual(gre.version, 0)
        inner = IPver(scapy.compat.raw(gre.payload))
        payload_info = self.payload_to_info(inner[Raw])
        self.info = self.packet_infos[payload_info.index]
        self.assertEqual(payload_info.src, self.pg0.sw_if_index)
        self.assertEqual(
            scapy.compat.raw(inner), scapy.compat.raw(self.info.data[IPver])
        )

    def checkCapture(self, encap, isv4, src_ip_sticky=False):
        self.pg0.assert_nothing_captured()
        out = self.pg1.get_capture(len(self.packets))

        load = [0] * len(self.ass)
        sticky_as = {}
        self.info = None
        for p in out:
            try:
                asid = 0
                gre = None
                if encap == "gre4":
                    ip = p[IP]
                    asid = int(ip.dst.split(".")[3])
                    self.assertEqual(ip.version, 4)
                    self.assertEqual(ip.flags, 0)
                    self.assertEqual(ip.src, "39.40.41.42")
                    self.assertEqual(ip.dst, "10.0.0.%u" % asid)
                    self.assertEqual(ip.proto, 47)
                    self.assertEqual(len(ip.options), 0)
                    gre = p[GRE]
                    self.checkInner(gre, isv4)
                elif encap == "gre6":
                    ip = p[IPv6]
                    asid = ip.dst.split(":")
                    asid = asid[len(asid) - 1]
                    asid = 0 if asid == "" else int(asid)
                    self.assertEqual(ip.version, 6)
                    self.assertEqual(ip.tc, 0)
                    self.assertEqual(ip.fl, 0)
                    self.assertEqual(ip.src, "2004::1")
                    self.assertEqual(
                        socket.inet_pton(socket.AF_INET6, ip.dst),
                        socket.inet_pton(socket.AF_INET6, "2002::%u" % asid),
                    )
                    self.assertEqual(ip.nh, 47)
                    # self.assertEqual(len(ip.options), 0)
                    gre = GRE(scapy.compat.raw(p[IPv6].payload))
                    self.checkInner(gre, isv4)
                elif encap == "l3dsr":
                    ip = p[IP]
                    asid = int(ip.dst.split(".")[3])
                    self.assertEqual(ip.version, 4)
                    self.assertEqual(ip.flags, 0)
                    self.assertEqual(ip.dst, "10.0.0.%u" % asid)
                    self.assertEqual(ip.tos, 0x1C)
                    self.assertEqual(len(ip.options), 0)
                    self.assert_ip_checksum_valid(p)
                    if ip.proto == IP_PROTOS.tcp:
                        self.assert_tcp_checksum_valid(p)
                    elif ip.proto == IP_PROTOS.udp:
                        self.assert_udp_checksum_valid(p)
                elif encap == "nat4":
                    ip = p[IP]
                    asid = int(ip.dst.split(".")[3])
                    self.assertEqual(ip.version, 4)
                    self.assertEqual(ip.flags, 0)
                    self.assertEqual(ip.dst, "10.0.0.%u" % asid)
                    self.assertEqual(ip.proto, 17)
                    self.assertEqual(len(ip.options), 0)
                    udp = p[UDP]
                    self.assertEqual(udp.dport, 3307)
                elif encap == "nat6":
                    ip = p[IPv6]
                    asid = ip.dst.split(":")
                    asid = asid[len(asid) - 1]
                    asid = 0 if asid == "" else int(asid)
                    self.assertEqual(ip.version, 6)
                    self.assertEqual(ip.tc, 0)
                    self.assertEqual(ip.fl, 0)
                    self.assertEqual(
                        socket.inet_pton(socket.AF_INET6, ip.dst),
                        socket.inet_pton(socket.AF_INET6, "2002::%u" % asid),
                    )
                    self.assertEqual(ip.nh, 17)
                    self.assertGreaterEqual(ip.hlim, 63)
                    udp = UDP(scapy.compat.raw(p[IPv6].payload))
                    self.assertEqual(udp.dport, 3307)
                load[asid] += 1

                # In case of source ip sticky, check that packets with same
                # src_ip are routed to same as.
                if src_ip_sticky and sticky_as.get(ip.src, asid) != asid:
                    raise Exception("Packets with same src_ip are routed to another as")
                sticky_as[ip.src] = asid

            except:
                self.logger.error(ppp("Unexpected or invalid packet:", p))
                raise

        # This is just to roughly check that the balancing algorithm
        # is not completely biased.
        for asid in self.ass:
            if load[asid] < int(len(self.packets) / (len(self.ass) * 2)):
                self.logger.error(
                    "ASS is not balanced: load[%d] = %d" % (asid, load[asid])
                )
                raise Exception("Load Balancer algorithm is biased")

    def test_lb_ip4_gre4(self):
        """Load Balancer IP4 GRE4 on vip case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 encap gre4")
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u" % (asid))

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="gre4", isv4=True)

        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u del" % (asid))
            self.vapi.cli("lb vip 90.0.0.0/8 encap gre4 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip6_gre4(self):
        """Load Balancer IP6 GRE4 on vip case"""

        try:
            self.vapi.cli("lb vip 2001::/16 encap gre4")
            for asid in self.ass:
                self.vapi.cli("lb as 2001::/16 10.0.0.%u" % (asid))

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=False))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre4", isv4=False)
        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 2001::/16 10.0.0.%u del" % (asid))
            self.vapi.cli("lb vip 2001::/16 encap gre4 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_gre6(self):
        """Load Balancer IP4 GRE6 on vip case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 encap gre6")
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 2002::%u" % (asid))

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre6", isv4=True)
        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 2002::%u del" % (asid))
            self.vapi.cli("lb vip 90.0.0.0/8 encap gre6 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip6_gre6(self):
        """Load Balancer IP6 GRE6 on vip case"""
        try:
            self.vapi.cli("lb vip 2001::/16 encap gre6")
            for asid in self.ass:
                self.vapi.cli("lb as 2001::/16 2002::%u" % (asid))

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=False))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre6", isv4=False)
        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 2001::/16 2002::%u del" % (asid))
            self.vapi.cli("lb vip 2001::/16 encap gre6 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_gre4_port(self):
        """Load Balancer IP4 GRE4 on per-port-vip case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 protocol udp port 20000 encap gre4")
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="gre4", isv4=True)

        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u del" % (asid)
                )
            self.vapi.cli("lb vip 90.0.0.0/8 protocol udp port 20000 encap gre4 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip6_gre4_port(self):
        """Load Balancer IP6 GRE4 on per-port-vip case"""

        try:
            self.vapi.cli("lb vip 2001::/16 protocol udp port 20000 encap gre4")
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 10.0.0.%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=False))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre4", isv4=False)
        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 10.0.0.%u del" % (asid)
                )
            self.vapi.cli("lb vip 2001::/16 protocol udp port 20000 encap gre4 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_gre6_port(self):
        """Load Balancer IP4 GRE6 on per-port-vip case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 protocol udp port 20000 encap gre6")
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 2002::%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre6", isv4=True)
        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 2002::%u del" % (asid)
                )
            self.vapi.cli("lb vip 90.0.0.0/8 protocol udp port 20000 encap gre6 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip6_gre6_port(self):
        """Load Balancer IP6 GRE6 on per-port-vip case"""
        try:
            self.vapi.cli("lb vip 2001::/16 protocol udp port 20000 encap gre6")
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 2002::%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=False))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()

            self.checkCapture(encap="gre6", isv4=False)
        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 2002::%u del" % (asid)
                )
            self.vapi.cli("lb vip 2001::/16 protocol udp port 20000 encap gre6 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_l3dsr(self):
        """Load Balancer IP4 L3DSR on vip case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 encap l3dsr dscp 7")
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u" % (asid))

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="l3dsr", isv4=True)

        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u del" % (asid))
            self.vapi.cli("lb vip 90.0.0.0/8 encap l3dsr dscp 7 del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_l3dsr_src_ip_sticky(self):
        """Load Balancer IP4 L3DSR on vip with src_ip_sticky case"""
        try:
            self.vapi.cli("lb vip 90.0.0.0/8 encap l3dsr dscp 7 src_ip_sticky")
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u" % (asid))

            # Generate duplicated packets
            pkts = self.generatePackets(self.pg0, isv4=True)
            pkts = pkts[: len(pkts) // 2]
            pkts = pkts + pkts

            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="l3dsr", isv4=True, src_ip_sticky=True)

        finally:
            for asid in self.ass:
                self.vapi.cli("lb as 90.0.0.0/8 10.0.0.%u del" % (asid))
            self.vapi.cli("lb vip 90.0.0.0/8 encap l3dsr dscp 7 src_ip_sticky del")
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_l3dsr_port(self):
        """Load Balancer IP4 L3DSR on per-port-vip case"""
        try:
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap l3dsr dscp 7"
            )
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="l3dsr", isv4=True)

        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u del" % (asid)
                )
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap l3dsr dscp 7 del"
            )
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_l3dsr_port_src_ip_sticky(self):
        """Load Balancer IP4 L3DSR on per-port-vip with src_ip_sticky case"""
        try:
            # This VIP at port 1000 does not receive packets, but is defined
            # as a dummy to verify that the src_ip_sticky flag can be set
            # independently for each port.
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 10000 encap l3dsr dscp 7"
            )
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap l3dsr dscp 7 src_ip_sticky"
            )
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u" % (asid)
                )

            # Generate duplicated packets
            pkts = self.generatePackets(self.pg0, isv4=True)
            pkts = pkts[: len(pkts) // 2]
            pkts = pkts + pkts

            self.pg0.add_stream(pkts)
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="l3dsr", isv4=True, src_ip_sticky=True)

        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u del" % (asid)
                )
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap l3dsr dscp 7 src_ip_sticky del"
            )
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 10000 encap l3dsr dscp 7 del"
            )
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip4_nat4_port(self):
        """Load Balancer IP4 NAT4 on per-port-vip case"""
        try:
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap nat4"
                " type clusterip target_port 3307"
            )
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=True))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="nat4", isv4=True)

        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 90.0.0.0/8 protocol udp port 20000 10.0.0.%u del" % (asid)
                )
            self.vapi.cli(
                "lb vip 90.0.0.0/8 protocol udp port 20000 encap nat4"
                " type clusterip target_port 3307 del"
            )
            self.vapi.cli("test lb flowtable flush")

    def test_lb_ip6_nat6_port(self):
        """Load Balancer IP6 NAT6 on per-port-vip case"""
        try:
            self.vapi.cli(
                "lb vip 2001::/16 protocol udp port 20000 encap nat6"
                " type clusterip target_port 3307"
            )
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 2002::%u" % (asid)
                )

            self.pg0.add_stream(self.generatePackets(self.pg0, isv4=False))
            self.pg_enable_capture(self.pg_interfaces)
            self.pg_start()
            self.checkCapture(encap="nat6", isv4=False)

        finally:
            for asid in self.ass:
                self.vapi.cli(
                    "lb as 2001::/16 protocol udp port 20000 2002::%u del" % (asid)
                )
            self.vapi.cli(
                "lb vip 2001::/16 protocol udp port 20000 encap nat6"
                " type clusterip target_port 3307 del"
            )
            self.vapi.cli("test lb flowtable flush")