mirror of
https://gitlab.isc.org/isc-projects/bind9
synced 2025-08-22 18:19:42 +00:00
dd7bb617be
- make qname-minimization option tristate {strict,relaxed,disabled}
- go straight for the record if we hit NXDOMAIN in relaxed mode
- go straight for the record after 3 labels without new delegation or 7 labels total
- use start of fetch (and not time of response) as 'now' time for querying cache for
zonecut when following delegation.
222 lines
8.1 KiB
Python
Executable File
222 lines
8.1 KiB
Python
Executable File
############################################################################
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# Copyright (C) Internet Systems Consortium, Inc. ("ISC")
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#
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# This Source Code Form is subject to the terms of the Mozilla Public
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# License, v. 2.0. If a copy of the MPL was not distributed with this
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# file, You can obtain one at http://mozilla.org/MPL/2.0/.
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#
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# See the COPYRIGHT file distributed with this work for additional
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# information regarding copyright ownership.
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############################################################################
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from __future__ import print_function
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import os
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import sys
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import signal
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import socket
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import select
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from datetime import datetime, timedelta
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import time
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import functools
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import dns, dns.message, dns.query
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from dns.rdatatype import *
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from dns.rdataclass import *
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from dns.rcode import *
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from dns.name import *
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# Log query to file
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def logquery(type, qname):
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with open("qlog", "a") as f:
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f.write("%s %s\n", type, qname)
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############################################################################
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# Respond to a DNS query.
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# For good. it serves:
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# ns2.good. IN A 10.53.0.2
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# zoop.boing.good. NS ns3.good.
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# ns3.good. IN A 10.53.0.3
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# too.many.labels.a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.good. A 192.0.2.2
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# it responds properly (with NODATA empty response) to non-empty terminals
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#
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# For slow. it works the same as for good., but each response is delayed by 400 miliseconds
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#
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# For bad. it works the same as for good., but returns NXDOMAIN to non-empty terminals
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#
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# For 1.0.0.2.ip6.arpa it serves
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# 1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.f.4.0.1.0.0.2.ip6.arpa. IN PTR nee.com.
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# 1.0.0.2.ip6.arpa. IN NS ns2.good
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# ip6.arpa. IN NS ns2.good
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############################################################################
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def create_response(msg):
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m = dns.message.from_wire(msg)
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qname = m.question[0].name.to_text()
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lqname = qname.lower()
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labels = lqname.split('.')
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# get qtype
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rrtype = m.question[0].rdtype
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typename = dns.rdatatype.to_text(rrtype)
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bad = False
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slow = False
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# log this query
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with open("query.log", "a") as f:
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f.write("%s %s\n" % (typename, lqname))
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print("%s %s" % (typename, lqname), end=" ")
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r = dns.message.make_response(m)
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r.set_rcode(NOERROR)
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if lqname.endswith("1.0.0.2.ip6.arpa."):
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# Direct query - give direct answer
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if lqname == "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.f.4.0.1.0.0.2.ip6.arpa." and rrtype == PTR:
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# Direct query - give direct answer
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r.answer.append(dns.rrset.from_text("1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.f.4.0.1.0.0.2.ip6.arpa.", 1, IN, PTR, "nee.com."))
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elif lqname == "1.0.0.2.ip6.arpa." and rrtype == NS:
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# NS query at the apex
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r.answer.append(dns.rrset.from_text("1.0.0.2.ip6.arpa.", 1, IN, NS, "ns2.good."))
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elif "1.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.0.8.f.4.0.1.0.0.2.ip6.arpa.".endswith(lqname):
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# NODATA answer
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r.authority.append(dns.rrset.from_text("1.0.0.2.ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1"))
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else:
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# NXDOMAIN
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r.authority.append(dns.rrset.from_text("1.0.0.2.ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1"))
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r.set_rcode(NXDOMAIN)
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return r
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elif lqname.endswith("ip6.arpa."):
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if lqname == "ip6.arpa." and rrtype == NS:
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# NS query at the apex
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r.answer.append(dns.rrset.from_text("ip6.arpa.", 1, IN, NS, "ns2.good."))
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elif "1.0.0.2.ip6.arpa.".endswith(lqname):
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# NODATA answer
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r.authority.append(dns.rrset.from_text("ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1"))
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else:
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# NXDOMAIN
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r.authority.append(dns.rrset.from_text("ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1"))
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r.set_rcode(NXDOMAIN)
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return r
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elif lqname.endswith("bad."):
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bad = True
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suffix = "bad."
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lqname = lqname[:-4]
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elif lqname.endswith("good."):
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suffix = "good."
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lqname = lqname[:-5]
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elif lqname.endswith("slow."):
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slow = True
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suffix = "slow."
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lqname = lqname[:-5]
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else:
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r.set_rcode(REFUSED)
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return r
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# Good/bad differs only in how we treat non-empty terminals
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if lqname.endswith("zoop.boing."):
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r.authority.append(dns.rrset.from_text("zoop.boing." + suffix, 1, IN, NS, "ns3." + suffix))
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elif lqname == "many.labels.a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z." and rrtype == A:
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r.answer.append(dns.rrset.from_text(lqname + suffix, 1, IN, A, "192.0.2.2"))
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elif lqname == "" and rrtype == NS:
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r.answer.append(dns.rrset.from_text(suffix, 1, IN, NS, "ns2." + suffix))
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elif lqname == "ns2." and rrtype == A:
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r.answer.append(dns.rrset.from_text("ns2."+suffix, 1, IN, A, "10.53.0.2"))
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elif lqname == "ns2." and rrtype == AAAA:
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r.answer.append(dns.rrset.from_text("ns2."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::2"))
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elif lqname == "ns3." and rrtype == A:
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r.answer.append(dns.rrset.from_text("ns3."+suffix, 1, IN, A, "10.53.0.3"))
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elif lqname == "ns3." and rrtype == AAAA:
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r.answer.append(dns.rrset.from_text("ns3."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::3"))
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elif lqname == "a.bit.longer.ns.name." and rrtype == A:
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r.answer.append(dns.rrset.from_text("a.bit.longer.ns.name."+suffix, 1, IN, A, "10.53.0.4"))
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elif lqname == "a.bit.longer.ns.name." and rrtype == AAAA:
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r.answer.append(dns.rrset.from_text("a.bit.longer.ns.name."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::4"))
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else:
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r.authority.append(dns.rrset.from_text(suffix, 1, IN, SOA, "ns2." + suffix + " hostmaster.arpa. 2018050100 1 1 1 1"))
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if bad or not \
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("icky.icky.icky.ptang.zoop.boing.".endswith(lqname) or \
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"many.labels.a.b.c.d.e.f.g.h.i.j.k.l.m.n.o.p.q.r.s.t.u.v.w.x.y.z.".endswith(lqname) or \
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"a.bit.longer.ns.name.".endswith(lqname)):
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r.set_rcode(NXDOMAIN)
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if slow:
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time.sleep(0.2)
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return r
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def sigterm(signum, frame):
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print ("Shutting down now...")
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os.remove('ans.pid')
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running = False
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sys.exit(0)
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############################################################################
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# Main
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#
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# Set up responder and control channel, open the pid file, and start
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# the main loop, listening for queries on the query channel or commands
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# on the control channel and acting on them.
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############################################################################
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ip4 = "10.53.0.2"
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ip6 = "fd92:7065:b8e:ffff::2"
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try: port=int(os.environ['PORT'])
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except: port=5300
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query4_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
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query4_socket.bind((ip4, port))
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havev6 = True
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try:
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query6_socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM)
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try:
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query6_socket.bind((ip6, port))
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except:
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query6_socket.close()
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havev6 = False
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except:
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havev6 = False
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signal.signal(signal.SIGTERM, sigterm)
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f = open('ans.pid', 'w')
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pid = os.getpid()
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print (pid, file=f)
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f.close()
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running = True
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print ("Listening on %s port %d" % (ip4, port))
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if havev6:
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print ("Listening on %s port %d" % (ip6, port))
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print ("Ctrl-c to quit")
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if havev6:
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input = [query4_socket, query6_socket]
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else:
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input = [query4_socket]
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while running:
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try:
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inputready, outputready, exceptready = select.select(input, [], [])
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except select.error as e:
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break
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except socket.error as e:
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break
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except KeyboardInterrupt:
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break
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for s in inputready:
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if s == query4_socket or s == query6_socket:
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print ("Query received on %s" %
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(ip4 if s == query4_socket else ip6), end=" ")
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# Handle incoming queries
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msg = s.recvfrom(65535)
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rsp = create_response(msg[0])
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if rsp:
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print(dns.rcode.to_text(rsp.rcode()))
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s.sendto(rsp.to_wire(), msg[1])
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else:
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print("NO RESPONSE")
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if not running:
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break
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