#!/usr/bin/env python3

import unittest

from framework import VppTestCase
from asfframework import VppTestRunner

from scapy.packet import Raw
from scapy.layers.l2 import Ether
from scapy.layers.inet import IP, UDP
from scapy.layers.inet6 import IPv6

from vpp_papi import VppEnum

N_PKTS = 63


class TestURPF(VppTestCase):
    """Unicast Reverse Path Forwarding Test Case"""

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

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

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

        # create 4 pg interfaces so there are a few addresses
        # in the FIB
        self.create_pg_interfaces(range(4))

        for i in self.pg_interfaces:
            i.admin_up()
            i.config_ip4()
            i.resolve_arp()
            i.config_ip6()
            i.resolve_ndp()

    def tearDown(self):
        for i in self.pg_interfaces:
            i.unconfig_ip4()
            i.unconfig_ip6()
            i.admin_down()
        super(TestURPF, self).tearDown()

    def test_urpf4(self):
        """uRPF IP4"""

        e = VppEnum
        p_spoof_loose = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IP(src="3.3.3.3", dst=self.pg1.remote_ip4)
            / UDP(sport=1234, dport=1234)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS
        p_spoof_strict = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IP(src=self.pg2.remote_ip4, dst=self.pg1.remote_ip4)
            / UDP(sport=1234, dport=1234)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS
        p_good = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IP(src=self.pg0.remote_ip4, dst=self.pg1.remote_ip4)
            / UDP(sport=1234, dport=1234)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS

        #
        # before adding the uRPF, ensure all packets are forwarded
        #
        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_loose, self.pg1)

        #
        # apply loose uRPF check on pg0 rx
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_LOOSE,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg0.sw_if_index,
        )

        # good packets still pass
        self.send_and_expect(self.pg0, p_good, self.pg1)
        # packets from address for which there is a route are forwarded
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        # packets from address to which there is no route are dropped
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip4-rx-urpf-loose/uRPF Drop", N_PKTS)

        #
        # crank it up to strict mode
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_STRICT,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg0.sw_if_index,
        )

        # good packets still pass
        self.send_and_expect(self.pg0, p_good, self.pg1)
        # packets that would not be routed back thru pg0 are dropped
        self.send_and_assert_no_replies(self.pg0, p_spoof_strict)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip4-rx-urpf-strict/uRPF Drop", 2 * N_PKTS)

        #
        # disable uRPF, all traffic should pass
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_OFF,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg0.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_loose, self.pg1)

        #
        # Now apply in the TX direction
        #  for loose it is the same deal, they should not be forwarded
        #  if there's no route
        #  for strict they should not be forwarded if they would be
        #  forwarded thru that interface.
        #
        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_LOOSE,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg1.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip4-tx-urpf-loose/uRPF Drop", N_PKTS)

        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_STRICT,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg1.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        # the strict packet, from a peer is allowed, since it does
        # not forward via pg1
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip4-tx-urpf-strict/uRPF Drop", N_PKTS)

        # change the strict packet so that it would forward through pg1
        p_spoof_strict = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IP(src=self.pg1.remote_ip4, dst=self.pg1.remote_ip4)
            / UDP(sport=1234, dport=1234)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS

        self.send_and_assert_no_replies(self.pg0, p_spoof_strict)
        self.assert_error_counter_equal("/err/ip4-tx-urpf-strict/uRPF Drop", 2 * N_PKTS)

        # cleanup
        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_OFF,
            af=e.vl_api_address_family_t.ADDRESS_IP4,
            sw_if_index=self.pg1.sw_if_index,
        )

    def test_urpf6(self):
        """uRPF IP6"""

        e = VppEnum
        p_spoof_loose = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IPv6(src="3::3", dst=self.pg1.remote_ip6)
            / UDP(sport=1236, dport=1236)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS
        p_spoof_strict = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IPv6(src=self.pg2.remote_ip6, dst=self.pg1.remote_ip6)
            / UDP(sport=1236, dport=1236)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS
        p_good = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IPv6(src=self.pg0.remote_ip6, dst=self.pg1.remote_ip6)
            / UDP(sport=1236, dport=1236)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS

        #
        # before adding the uRPF, ensure all packets are forwarded
        #
        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_loose, self.pg1)

        #
        # apply loose uRPF check on pg0 rx
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_LOOSE,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg0.sw_if_index,
        )

        # good packets still pass
        self.send_and_expect(self.pg0, p_good, self.pg1)
        # packets from address for which there is a route are forwarded
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        # packets from address to which there is no route are dropped
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip6-rx-urpf-loose/uRPF Drop", N_PKTS)

        #
        # crank it up to strict mode
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_STRICT,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg0.sw_if_index,
        )

        # good packets still pass
        self.send_and_expect(self.pg0, p_good, self.pg1)
        # packets that would not be routed back thru pg0 are dropped
        self.send_and_assert_no_replies(self.pg0, p_spoof_strict)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip6-rx-urpf-strict/uRPF Drop", 2 * N_PKTS)

        #
        # disable uRPF, all traffic should pass
        #
        self.vapi.urpf_update(
            is_input=True,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_OFF,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg0.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_loose, self.pg1)

        #
        # Now apply in the TX direction
        #  for loose it is the same deal, they should not be forwarded
        #  if there's no route
        #  for strict they should not be forwarded if they would be
        #  forwarded thru that interface.
        #
        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_LOOSE,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg1.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip6-tx-urpf-loose/uRPF Drop", N_PKTS)

        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_STRICT,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg1.sw_if_index,
        )

        self.send_and_expect(self.pg0, p_good, self.pg1)
        # the strict packet, from a peer is allowed, since it does
        # not forward via pg1
        self.send_and_expect(self.pg0, p_spoof_strict, self.pg1)
        self.send_and_assert_no_replies(self.pg0, p_spoof_loose)

        self.assert_error_counter_equal("/err/ip6-tx-urpf-strict/uRPF Drop", N_PKTS)

        # change the strict packet so that it would forward through pg1
        p_spoof_strict = (
            Ether(dst=self.pg0.local_mac, src=self.pg0.remote_mac)
            / IPv6(src=self.pg1.remote_ip6, dst=self.pg1.remote_ip6)
            / UDP(sport=1236, dport=1236)
            / Raw(b"\xa5" * 100)
        ) * N_PKTS

        self.send_and_assert_no_replies(self.pg0, p_spoof_strict)
        self.assert_error_counter_equal("/err/ip6-tx-urpf-strict/uRPF Drop", 2 * N_PKTS)

        # cleanup
        self.vapi.urpf_update(
            is_input=False,
            mode=e.vl_api_urpf_mode_t.URPF_API_MODE_OFF,
            af=e.vl_api_address_family_t.ADDRESS_IP6,
            sw_if_index=self.pg1.sw_if_index,
        )


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