#!/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_