1 # ldd - DNS implementation in Python
2 # Copyright (C) 2006 Fredrik Tolf <fredrik@dolda2000.com>
4 # This program is free software; you can redistribute it and/or modify
5 # it under the terms of the GNU General Public License as published by
6 # the Free Software Foundation; either version 2 of the License, or
7 # (at your option) any later version.
9 # This program is distributed in the hope that it will be useful,
10 # but WITHOUT ANY WARRANTY; without even the implied warranty of
11 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 # GNU General Public License for more details.
14 # You should have received a copy of the GNU General Public License
15 # along with this program; if not, write to the Free Software
16 # Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
30 logger = logging.getLogger("ldd.server")
33 class socklistener(threading.Thread):
34 def __init__(self, server):
35 threading.Thread.__init__(self)
40 def __init__(self, addr, sk):
45 logger.debug("sending response to %04x", pkt.qid)
46 self.sk.sendto(pkt.encode(), self.addr)
51 for af, sk in self.server.sockets:
52 p.register(sk.fileno(), select.POLLIN)
55 except select.error, e:
56 if e[0] == errno.EINTR:
60 if event & select.POLLIN == 0:
62 for af, sk in self.server.sockets:
67 req, addr = sk.recvfrom(65536)
69 pkt = proto.decodepacket(req)
70 except proto.malformedpacket, inst:
71 resp = proto.packet(inst.qid, ["resp"])
72 resp.rescode = proto.FORMERR
73 sk.sendto(resp.encode(), addr)
75 logger.debug("got request (%04x) from %s", pkt.qid, addr[0])
76 pkt.addr = (af,) + addr
77 self.server.queuereq(pkt, dnsserver.socklistener.sender(addr, sk))
82 class dispatcher(threading.Thread):
83 def __init__(self, server):
84 threading.Thread.__init__(self)
90 req = self.server.dequeuereq()
93 resp = self.server.handle(pkt)
95 resp = proto.responsefor(pkt, proto.SERVFAIL)
98 class queuemonitor(threading.Thread):
99 def __init__(self, server):
100 threading.Thread.__init__(self)
104 while(self.server.running):
105 self.server.queuelock.acquire()
106 if len(self.server.queue) > 0:
107 peeked = self.server.queue[0]
110 self.server.queuelock.release()
111 if peeked is not None:
112 if time.time() - peeked[0] > 1:
113 newdsp = dnsserver.dispatcher(self.server)
114 self.server.dispatchers += [newdsp]
116 logger.debug("starting new dispatcher, there are now %i", len(self.server.dispatchers))
124 self.dispatchers = []
126 self.queuelock = threading.Condition()
129 def handle(self, pkt):
132 if len(self.knownkeys) > 0:
134 dnssec.tsigverify(pkt, self.knownkeys)
136 for query in pkt.qlist:
138 for zone in self.zones:
139 if query.name in zone.origin:
142 elif len(zone.origin) > len(match.origin):
147 curresp = match.handle(query, pkt)
153 if resp is not None and resp.tsigctx is not None and not resp.signed:
154 resp.tsigctx.signpkt(resp)
158 def addsock(self, af, socket):
159 self.sockets += [(af, socket)]
161 def addzone(self, zone):
164 def queuereq(self, req, sender):
165 self.queuelock.acquire()
166 self.queue += [(time.time(), req, sender)]
167 logger.debug("queue length+: %i", len(self.queue))
168 self.queuelock.notify()
169 self.queuelock.release()
171 def dequeuereq(self):
172 self.queuelock.acquire()
173 if len(self.queue) == 0:
174 self.queuelock.wait()
175 if len(self.queue) > 0:
177 self.queue = self.queue[1:]
180 logger.debug("queue length-: %i", len(self.queue))
181 self.queuelock.release()
189 raise Exception("already running")
190 lst = dnsserver.socklistener(self)
194 newdsp = dnsserver.dispatcher(self)
195 self.dispatchers += [newdsp]
198 self.monitor = dnsserver.queuemonitor(self)
205 for dsp in self.dispatchers:
207 self.queuelock.acquire()
208 self.queuelock.notifyAll()
209 self.queuelock.release()
210 for dsp in self.dispatchers + []:
212 self.dispatchers.remove(dsp)
216 def resolver(self, addr = None):
217 class myres(resolver.resolver):
218 def __init__(self, server, addr):
221 def resolve(self, packet):
222 if self.addr is not None:
223 packet.addr = self.addr
224 packet.setflags(["internal"])
225 return self.server.handle(packet)
226 return myres(self, addr)
229 def __init__(self, origin, handler):
230 if type(origin) == str:
231 self.origin = dn.fromstring(origin)
232 self.origin.rooted = True
235 self.handler = handler
237 def handle(self, query, pkt):
238 resp = self.handler.handle(query, pkt, self.origin)
241 class authzone(zone):
242 def __init__(self, aurecres, *args):
243 self.aurecres = aurecres
244 zone.__init__(self, *args)
246 def handle(self, query, pkt):
247 resp = zone.handle(self, query, pkt)
248 if not "internal" in pkt.flags:
250 resp = proto.responsefor(pkt)
251 soa = zone.handle(self, rec.rrhead(self.origin, "SOA"), pkt)
252 resp.aulist += soa.anlist
253 resp.rescode = proto.NXDOMAIN
255 resolver.resolvecnames(resp, self.aurecres)
256 nsrecs = zone.handle(self, rec.rrhead(self.origin, "NS"), pkt)
257 if nsrecs is not None:
258 resp.aulist += nsrecs.anlist
259 for rr in nsrecs.anlist:
260 resolver.resolveadditional(resp, rr, self.aurecres)
264 resp.setflags(["auth"])
268 def handle(self, query, pkt, origin):
271 class forwarder(handler):
272 def __init__(self, nameserver, timeout = 2000, retries = 3):
273 self.nameserver = nameserver
274 self.timeout = timeout
275 self.retries = retries
277 def handle(self, query, pkt, origin):
278 sk = socket.socket(self.nameserver[0], socket.SOCK_DGRAM)
281 p.register(sk.fileno(), select.POLLIN)
282 for i in range(self.retries):
283 sk.sendto(pkt.encode(), self.nameserver[1:])
284 fds = p.poll(self.timeout)
285 if (sk.fileno(), select.POLLIN) in fds:
289 resp = sk.recv(65536)
290 resp = proto.decodepacket(resp)
293 class recurser(handler):
294 def __init__(self, resolver):
295 self.resolver = resolver
297 def handle(self, query, pkt, origin):
299 resp = self.resolver.resolve(pkt)
300 except resolver.error:
304 class chain(handler):
305 def __init__(self, chain):
308 def add(self, handler):
309 self.chain += [handler]
311 def handle(self, *args):
313 resp = h.handle(*args)