1############################################################################ 2# Copyright (C) Internet Systems Consortium, Inc. ("ISC") 3# 4# This Source Code Form is subject to the terms of the Mozilla Public 5# License, v. 2.0. If a copy of the MPL was not distributed with this 6# file, You can obtain one at http://mozilla.org/MPL/2.0/. 7# 8# See the COPYRIGHT file distributed with this work for additional 9# information regarding copyright ownership. 10############################################################################ 11 12from __future__ import print_function 13import os 14import sys 15import signal 16import socket 17import select 18from datetime import datetime, timedelta 19import time 20import functools 21 22import dns, dns.message, dns.query, dns.flags 23from dns.rdatatype import * 24from dns.rdataclass import * 25from dns.rcode import * 26from dns.name import * 27 28 29# Log query to file 30def logquery(type, qname): 31 with open("qlog", "a") as f: 32 f.write("%s %s\n", type, qname) 33 34############################################################################ 35# Respond to a DNS query. 36# For good. it serves: 37# ns2.good. IN A 10.53.0.2 38# zoop.boing.good. NS ns3.good. 39# ns3.good. IN A 10.53.0.3 40# 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 41# it responds properly (with NODATA empty response) to non-empty terminals 42# 43# For slow. it works the same as for good., but each response is delayed by 400 milliseconds 44# 45# For bad. it works the same as for good., but returns NXDOMAIN to non-empty terminals 46# 47# For ugly. it works the same as for good., but returns garbage to non-empty terminals 48# 49# For 1.0.0.2.ip6.arpa it serves 50# 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. 51# 1.0.0.2.ip6.arpa. IN NS ns2.good 52# ip6.arpa. IN NS ns2.good 53############################################################################ 54def create_response(msg): 55 m = dns.message.from_wire(msg) 56 qname = m.question[0].name.to_text() 57 lqname = qname.lower() 58 labels = lqname.split('.') 59 60 # get qtype 61 rrtype = m.question[0].rdtype 62 typename = dns.rdatatype.to_text(rrtype) 63 if typename == "A" or typename == "AAAA": 64 typename = "ADDR" 65 bad = False 66 ugly = False 67 slow = False 68 69 # log this query 70 with open("query.log", "a") as f: 71 f.write("%s %s\n" % (typename, lqname)) 72 print("%s %s" % (typename, lqname), end=" ") 73 74 r = dns.message.make_response(m) 75 r.set_rcode(NOERROR) 76 77 if lqname.endswith("1.0.0.2.ip6.arpa."): 78 # Direct query - give direct answer 79 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: 80 # Direct query - give direct answer 81 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.")) 82 r.flags |= dns.flags.AA 83 elif lqname == "1.0.0.2.ip6.arpa." and rrtype == NS: 84 # NS query at the apex 85 r.answer.append(dns.rrset.from_text("1.0.0.2.ip6.arpa.", 1, IN, NS, "ns2.good.")) 86 r.flags |= dns.flags.AA 87 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): 88 # NODATA answer 89 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")) 90 else: 91 # NXDOMAIN 92 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")) 93 r.set_rcode(NXDOMAIN) 94 return r 95 elif lqname.endswith("ip6.arpa."): 96 if lqname == "ip6.arpa." and rrtype == NS: 97 # NS query at the apex 98 r.answer.append(dns.rrset.from_text("ip6.arpa.", 1, IN, NS, "ns2.good.")) 99 r.flags |= dns.flags.AA 100 elif "1.0.0.2.ip6.arpa.".endswith(lqname): 101 # NODATA answer 102 r.authority.append(dns.rrset.from_text("ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1")) 103 else: 104 # NXDOMAIN 105 r.authority.append(dns.rrset.from_text("ip6.arpa.", 1, IN, SOA, "ns2.good. hostmaster.arpa. 2018050100 1 1 1 1")) 106 r.set_rcode(NXDOMAIN) 107 return r 108 elif lqname.endswith("bad."): 109 bad = True 110 suffix = "bad." 111 lqname = lqname[:-4] 112 elif lqname.endswith("ugly."): 113 ugly = True 114 suffix = "ugly." 115 lqname = lqname[:-5] 116 elif lqname.endswith("good."): 117 suffix = "good." 118 lqname = lqname[:-5] 119 elif lqname.endswith("slow."): 120 slow = True 121 suffix = "slow." 122 lqname = lqname[:-5] 123 elif lqname.endswith("fwd."): 124 suffix = "fwd." 125 lqname = lqname[:-4] 126 else: 127 r.set_rcode(REFUSED) 128 return r 129 130 # Good/bad/ugly differs only in how we treat non-empty terminals 131 if lqname.endswith("zoop.boing."): 132 r.authority.append(dns.rrset.from_text("zoop.boing." + suffix, 1, IN, NS, "ns3." + suffix)) 133 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: 134 r.answer.append(dns.rrset.from_text(lqname + suffix, 1, IN, A, "192.0.2.2")) 135 r.flags |= dns.flags.AA 136 elif lqname == "" and rrtype == NS: 137 r.answer.append(dns.rrset.from_text(suffix, 1, IN, NS, "ns2." + suffix)) 138 r.flags |= dns.flags.AA 139 elif lqname == "ns2." and rrtype == A: 140 r.answer.append(dns.rrset.from_text("ns2."+suffix, 1, IN, A, "10.53.0.2")) 141 r.flags |= dns.flags.AA 142 elif lqname == "ns2." and rrtype == AAAA: 143 r.answer.append(dns.rrset.from_text("ns2."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::2")) 144 r.flags |= dns.flags.AA 145 elif lqname == "ns3." and rrtype == A: 146 r.answer.append(dns.rrset.from_text("ns3."+suffix, 1, IN, A, "10.53.0.3")) 147 r.flags |= dns.flags.AA 148 elif lqname == "ns3." and rrtype == AAAA: 149 r.answer.append(dns.rrset.from_text("ns3."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::3")) 150 r.flags |= dns.flags.AA 151 elif lqname == "a.bit.longer.ns.name." and rrtype == A: 152 r.answer.append(dns.rrset.from_text("a.bit.longer.ns.name."+suffix, 1, IN, A, "10.53.0.4")) 153 r.flags |= dns.flags.AA 154 elif lqname == "a.bit.longer.ns.name." and rrtype == AAAA: 155 r.answer.append(dns.rrset.from_text("a.bit.longer.ns.name."+suffix, 1, IN, AAAA, "fd92:7065:b8e:ffff::4")) 156 r.flags |= dns.flags.AA 157 else: 158 r.authority.append(dns.rrset.from_text(suffix, 1, IN, SOA, "ns2." + suffix + " hostmaster.arpa. 2018050100 1 1 1 1")) 159 if bad or not \ 160 ("icky.icky.icky.ptang.zoop.boing.".endswith(lqname) or \ 161 "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 \ 162 "a.bit.longer.ns.name.".endswith(lqname)): 163 r.set_rcode(NXDOMAIN) 164 if ugly: 165 r.set_rcode(FORMERR) 166 if slow: 167 time.sleep(0.2) 168 return r 169 170 171def sigterm(signum, frame): 172 print ("Shutting down now...") 173 os.remove('ans.pid') 174 running = False 175 sys.exit(0) 176 177############################################################################ 178# Main 179# 180# Set up responder and control channel, open the pid file, and start 181# the main loop, listening for queries on the query channel or commands 182# on the control channel and acting on them. 183############################################################################ 184ip4 = "10.53.0.2" 185ip6 = "fd92:7065:b8e:ffff::2" 186 187try: port=int(os.environ['PORT']) 188except: port=5300 189 190query4_socket = socket.socket(socket.AF_INET, socket.SOCK_DGRAM) 191query4_socket.bind((ip4, port)) 192 193havev6 = True 194try: 195 query6_socket = socket.socket(socket.AF_INET6, socket.SOCK_DGRAM) 196 try: 197 query6_socket.bind((ip6, port)) 198 except: 199 query6_socket.close() 200 havev6 = False 201except: 202 havev6 = False 203 204signal.signal(signal.SIGTERM, sigterm) 205 206f = open('ans.pid', 'w') 207pid = os.getpid() 208print (pid, file=f) 209f.close() 210 211running = True 212 213print ("Listening on %s port %d" % (ip4, port)) 214if havev6: 215 print ("Listening on %s port %d" % (ip6, port)) 216print ("Ctrl-c to quit") 217 218if havev6: 219 input = [query4_socket, query6_socket] 220else: 221 input = [query4_socket] 222 223while running: 224 try: 225 inputready, outputready, exceptready = select.select(input, [], []) 226 except select.error as e: 227 break 228 except socket.error as e: 229 break 230 except KeyboardInterrupt: 231 break 232 233 for s in inputready: 234 if s == query4_socket or s == query6_socket: 235 print ("Query received on %s" % 236 (ip4 if s == query4_socket else ip6), end=" ") 237 # Handle incoming queries 238 msg = s.recvfrom(65535) 239 rsp = create_response(msg[0]) 240 if rsp: 241 print(dns.rcode.to_text(rsp.rcode())) 242 s.sendto(rsp.to_wire(), msg[1]) 243 else: 244 print("NO RESPONSE") 245 if not running: 246 break 247