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253 lines
8.4 KiB
253 lines
8.4 KiB
#!/usr/bin/env python
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# -*- coding: utf-8 -*-
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# Copyright (c) 2014 clowwindy
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#
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# Permission is hereby granted, free of charge, to any person obtaining a copy
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# of this software and associated documentation files (the "Software"), to deal
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# in the Software without restriction, including without limitation the rights
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# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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# copies of the Software, and to permit persons to whom the Software is
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be included in
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# all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
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# SOFTWARE.
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import socket
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import struct
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import common
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_request_count = 1
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# rfc1035
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# format
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# +---------------------+
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# | Header |
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# +---------------------+
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# | Question | the question for the name server
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# +---------------------+
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# | Answer | RRs answering the question
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# +---------------------+
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# | Authority | RRs pointing toward an authority
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# +---------------------+
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# | Additional | RRs holding additional information
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# +---------------------+
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#
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# header
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# 1 1 1 1 1 1
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# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | ID |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# |QR| Opcode |AA|TC|RD|RA| Z | RCODE |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | QDCOUNT |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | ANCOUNT |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | NSCOUNT |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | ARCOUNT |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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QTYPE_ANY = 255
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QTYPE_A = 1
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QTYPE_AAAA = 28
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QTYPE_CNAME = 5
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QCLASS_IN = 1
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def parse_ip(addrtype, data, length, offset):
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if addrtype == QTYPE_A:
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return socket.inet_ntop(socket.AF_INET, data[offset:offset + length])
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elif addrtype == QTYPE_AAAA:
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return socket.inet_ntop(socket.AF_INET6, data[offset:offset + length])
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elif addrtype == QTYPE_CNAME:
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return parse_name(data, offset, length)[1]
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else:
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return data
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def pack_address(address):
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address = address.strip('.')
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labels = address.split('.')
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results = []
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for label in labels:
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l = len(label)
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if l > 63:
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return None
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results.append(chr(l))
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results.append(label)
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results.append('\0')
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return ''.join(results)
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def pack_request(address):
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global _request_count
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header = struct.pack('!HBBHHHH', _request_count, 1, 0, 1, 0, 0, 0)
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addr = pack_address(address)
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qtype_qclass = struct.pack('!HH', QTYPE_ANY, QCLASS_IN)
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_request_count += 1
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if _request_count > 65535:
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_request_count = 1
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return header + addr + qtype_qclass
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def parse_name(data, offset, length=512):
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p = offset
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if (ord(data[offset]) & (128 + 64)) == (128 + 64):
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# pointer
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pointer = struct.unpack('!H', data[offset:offset + 2])[0]
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pointer = pointer & 0x3FFF
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if pointer == offset:
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return (0, None)
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return (2, parse_name(data, pointer))
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else:
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labels = []
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l = ord(data[p])
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while l > 0 and p < offset + length:
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if (l & (128 + 64)) == (128 + 64):
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# pointer
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pointer = struct.unpack('!H', data[p:p + 2])[0]
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pointer = pointer & 0x3FFF
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# if pointer == offset:
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# return (0, None)
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r = parse_name(data, pointer)
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labels.append(r[1])
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p += 2
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# pointer is the end
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return (p - offset + 1, '.'.join(labels))
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else:
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labels.append(data[p + 1:p + 1 + l])
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p += 1 + l
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l = ord(data[p])
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return (p - offset + 1, '.'.join(labels))
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# rfc1035
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# record
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# 1 1 1 1 1 1
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# 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | |
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# / /
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# / NAME /
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# | |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | TYPE |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | CLASS |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | TTL |
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# | |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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# | RDLENGTH |
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--|
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# / RDATA /
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# / /
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# +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
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def parse_record(data, offset, question=False):
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len, name = parse_name(data, offset)
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# TODO
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assert len
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if not question:
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record_type, record_class, record_ttl, record_rdlength = struct.unpack(
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'!HHiH', data[offset + len:offset + len + 10]
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)
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ip = parse_ip(record_type, data, record_rdlength, offset + len + 10)
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return len + 10 + record_rdlength, \
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(name, ip, record_type, record_class, record_ttl)
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else:
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record_type, record_class = struct.unpack(
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'!HH', data[offset + len:offset + len + 4]
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)
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return len + 4, (name, None, record_type, record_class, None, None)
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def unpack_response(data):
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try:
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if len(data) >= 12:
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header = struct.unpack('!HBBHHHH', data[:12])
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res_id = header[0]
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res_qr = header[1] & 128
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res_tc = header[1] & 2
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res_ra = header[2] & 128
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res_rcode = header[2] & 15
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# TODO check tc and rcode
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assert res_tc == 0
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assert res_rcode == 0
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res_qdcount = header[3]
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res_ancount = header[4]
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res_nscount = header[5]
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res_arcount = header[6]
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qds = []
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ans = []
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nss = []
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ars = []
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offset = 12
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for i in xrange(0, res_qdcount):
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l, r = parse_record(data, offset, True)
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offset += l
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if r:
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qds.append(r)
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for i in xrange(0, res_ancount):
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l, r = parse_record(data, offset)
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offset += l
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if r:
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ans.append(r)
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for i in xrange(0, res_nscount):
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l, r = parse_record(data, offset)
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offset += l
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if r:
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nss.append(r)
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for i in xrange(0, res_arcount):
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l, r = parse_record(data, offset)
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offset += l
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if r:
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ars.append(r)
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return ans
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except Exception as e:
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import traceback
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traceback.print_exc()
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return None
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def resolve(address, callback):
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# TODO async
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sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM, socket.SOL_UDP)
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req = pack_request(address)
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if req is None:
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# TODO
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return
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sock.sendto(req, ('8.8.8.8', 53))
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res, addr = sock.recvfrom(1024)
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parsed_res = unpack_response(res)
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callback(parsed_res)
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def test():
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def _callback(address):
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print address
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resolve('www.twitter.com', _callback)
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resolve('www.google.com', _callback)
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resolve('ipv6.google.com', _callback)
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resolve('ipv6.l.google.com', _callback)
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resolve('www.baidu.com', _callback)
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resolve('www.a.shifen.com', _callback)
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resolve('m.baidu.jp', _callback)
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if __name__ == '__main__':
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test()
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