54 lines
2.2 KiB
Python
54 lines
2.2 KiB
Python
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import time
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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, default_address, default_port, timeout, config):
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self.default_address = default_address
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self.default_port = default_port
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self.timeout = timeout
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self.config = config
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def resolve(self, request, handler):
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address = self.default_address
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port = self.default_port
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subnets = [ (net["local_range"], net["local_translated_range"]) for net in self.config.data["network"].values() ]
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qname = DNSLabel(request.q.qname)
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for dns in self.config.dns_servers:
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if dns["domain"] == str(qname)[-len(dns["domain"])-1:-1]:
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address = dns["ip"]
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try:
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proxy_r = request.send(address, 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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if address != self.default_address and address not in self.config.data["network"][self.config.local_network]["dns"].values():
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for rr in reply.rr:
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for (sub, trans) in subnets:
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if IPv4Address(rr.rdata) in IPv4Network(sub):
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rr.rdata.data = IPv4Address(translate(str(rr.rdata), sub, trans)).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, default_dns="1.1.1.1", default_port=53, timeout=5, port=53, address="0.0.0.0"):
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resolver = ProxyResolver(default_dns, default_port, timeout, 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(resolver, port=5353, address="0.0.0.0", logger=logger, handler=handler)
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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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