81 lines
2.9 KiB
Python
81 lines
2.9 KiB
Python
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import dns
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class DnsHandler(threading.Thread):
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def __init__(self, msgQueue, tsigKey, nsAddress, ttl, nullIp):
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threading.Thread.__init__(self)
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self.msgQueue = msgQueue
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self.nullIp = nullIp
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self.nsAddress = nsAddress
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self.ttl = ttl
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self.keyring = dns.tsigkeyring.from_text(tsigKey)
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def run(self):
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while(True):
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msg = self.msgQueue.get()
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if msg.successFlag:
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# success
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Logger.dbg("DnsManipulator: retrieved positive message")
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if not self.statusMap.has_key(msg.ip) or not self.statusMap[msg.ip]:
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self.statusMap[msg.ip] = True
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self.insertARR(msg.ip)
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self.notifyQueue.put(NotificationMessage("Server returned", "Server %s is back" % msg.ip))
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else:
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# failure
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Logger.dbg("DnsManipulator: retrieved negative message")
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if not self.statusMap.has_key(msg.ip) or self.statusMap[msg.ip]:
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self.statusMap[msg.ip] = False
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self.deleteARR(msg.ip)
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self.notifyQueue.put(NotificationMessage("Server unavailable", "Server %s has gone" % msg.ip))
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failureCnt = 0
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for v in self.statusMap.values():
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if not v:
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failureCnt += 1
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if failureCnt > 0 and not self.exitServerFlag:
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self.insertARR(self.exitServerIp)
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self.exitServerFlag = True
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if failureCnt == 0 and self.exitServerFlag:
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self.deleteARR(self.exitServerIp)
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self.exitServerFlag = False
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self.notifyQueue.put(NotificationMessage("All clear", "All clear, exit-server removed from DNS"))
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def insertARR(self, ip):
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# send A-RR insertion for ip to DNS server
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Logger.log("insert ARR %s" % ip)
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rr = dns.rdtypes.IN.A.A(dns.rdataclass.IN, dns.rdatatype.A, ip)
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u = dns.update.Update(self.zone, keyring=self.keyring)
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u.add(self.name, self.ttl, rr)
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r = dns.query.tcp(u, self.nsAddress)
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if r.rcode() != 0:
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# failure
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Logger.log("failure when inserting A-RR for %s" % ip)
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else:
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# success
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pass
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def deleteARR(self, ip):
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# send A-RR deletion for ip to DNS server
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Logger.log("delete ARR %s" % ip)
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rr = dns.rdtypes.IN.A.A(dns.rdataclass.IN, dns.rdatatype.A, ip)
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u = dns.update.Update(self.zone, keyring=self.keyring)
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u.delete(self.name, rr)
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r = dns.query.tcp(u, self.nsAddress)
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if r.rcode() != 0:
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# failure
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Logger.log("failure when deleting A-RR for %s" % ip)
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else:
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# success
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pass
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