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#!/usr/bin/env python3
import unittest
from framework import VppTestCase
from asfframework import VppTestRunner
from ipaddress import *
from scapy.layers.inet import IP, UDP
from scapy.layers.l2 import Ether
from scapy.layers.dns import DNS, DNSQR
class TestDns(VppTestCase):
"""Dns Test Cases"""
@classmethod
def setUpClass(cls):
super(TestDns, cls).setUpClass()
@classmethod
def tearDownClass(cls):
super(TestDns, cls).tearDownClass()
def setUp(self):
super(TestDns, self).setUp()
self.create_pg_interfaces(range(1))
for i in self.pg_interfaces:
i.admin_up()
i.config_ip4()
i.resolve_arp()
def tearDown(self):
super(TestDns, self).tearDown()
def create_stream(self, src_if):
"""Create input packet stream for defined interface.
:param VppInterface src_if: Interface to create packet stream for.
"""
good_request = (
Ether(dst=src_if.local_mac, src=src_if.remote_mac)
/ IP(src=src_if.remote_ip4)
/ UDP(sport=1234, dport=53)
/ DNS(rd=1, qd=DNSQR(qname="bozo.clown.org"))
)
bad_request = (
Ether(dst=src_if.local_mac, src=src_if.remote_mac)
/ IP(src=src_if.remote_ip4)
/ UDP(sport=1234, dport=53)
/ DNS(rd=1, qd=DNSQR(qname="no.clown.org"))
)
pkts = [good_request, bad_request]
return pkts
def verify_capture(self, dst_if, capture):
"""Verify captured input packet stream for defined interface.
:param VppInterface dst_if: Interface to verify captured packet stream
for.
:param list capture: Captured packet stream.
"""
self.logger.info("Verifying capture on interface %s" % dst_if.name)
for packet in capture:
dns = packet[DNS]
self.assertEqual(dns.an[0].rdata, "1.2.3.4")
def test_dns_unittest(self):
"""DNS Name Resolver Basic Functional Test"""
# Set up an upstream name resolver. We won't actually go there
self.vapi.dns_name_server_add_del(
is_ip6=0, is_add=1, server_address=IPv4Address("8.8.8.8").packed
)
# Enable name resolution
self.vapi.dns_enable_disable(enable=1)
# Manually add a static dns cache entry
self.logger.info(self.vapi.cli("dns cache add bozo.clown.org 1.2.3.4"))
# Test the binary API
rv = self.vapi.dns_resolve_name(name=b"bozo.clown.org")
self.assertEqual(rv.ip4_address, IPv4Address("1.2.3.4").packed)
# Configure 127.0.0.1/8 on the pg interface
self.vapi.sw_interface_add_del_address(
sw_if_index=self.pg0.sw_if_index, prefix="127.0.0.1/8"
)
# Send a couple of DNS request packets, one for bozo.clown.org
# and one for no.clown.org which won't resolve
pkts = self.create_stream(self.pg0)
self.pg0.add_stream(pkts)
self.pg_enable_capture(self.pg_interfaces)
self.pg_start()
pkts = self.pg0.get_capture(1)
self.verify_capture(self.pg0, pkts)
# Make sure that the cache contents are correct
str = self.vapi.cli("show dns cache verbose")
self.assertIn("1.2.3.4", str)
self.assertIn("[P] no.clown.org:", str)
if __name__ == "__main__":
unittest.main(testRunner=VppTestRunner)
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