54 lines
1.7 KiB
Python
54 lines
1.7 KiB
Python
import time
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import socket
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from ipaddress import IPv4Address, IPv4Network
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from dnslib import DNSRecord,RCODE,QTYPE
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from dnslib.server import DNSServer,DNSHandler,BaseResolver,DNSLogger
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from dnslib.label import DNSLabel
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from dnslib.ranges import IP4
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class ProxyResolver(BaseResolver):
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def __init__(self, config):
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self.timeout = config.dns_timeout
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self.config = config
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def resolve(self, request, handler):
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qname = DNSLabel(request.q.qname)
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dns = self.config.dns_server(str(qname))
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try:
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proxy_r = request.send(dns.address, dns.port, timeout=self.timeout)
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reply = DNSRecord.parse(proxy_r)
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except socket.timeout:
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reply = request.reply()
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reply.header.rcode = getattr(RCODE, 'NXDOMAIN')
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return reply
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if dns.network != None and dns.network != config.local_network:
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for rr in reply.rr:
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rr.rdata.data = IPv4Address(config.translate(str(rr.rdata), network)).packed
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reply.set_header_qa()
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return reply
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def translate(ip, untranslated_range, translated_range):
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for (loc, trans) in zip(IPv4Network(untranslated_range), IPv4Network(translated_range)):
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if str(loc) == ip:
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return str(trans)
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return ip
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def run(config):
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resolver = ProxyResolver(config)
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handler = DNSHandler
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logger = DNSLogger("+request,+reply,+truncated,+error,-recv,-send,-data")
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udp_server = DNSServer(
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resolver,
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port=config.listen_port,
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address=config.listen_address,
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logger=logger,
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handler=handler
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)
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udp_server.start_thread()
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while udp_server.isAlive():
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time.sleep(1)
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