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kaklik |
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# Written by Bram Cohen
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# see LICENSE.txt for license information
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from cStringIO import StringIO
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from socket import error as socketerror
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from traceback import print_exc
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try:
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True
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except:
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True = 1
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False = 0
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protocol_name = 'BitTorrent protocol'
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# header, reserved, download id, my id, [length, message]
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class NatCheck:
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def __init__(self, resultfunc, downloadid, peerid, ip, port, rawserver):
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self.resultfunc = resultfunc
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self.downloadid = downloadid
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self.peerid = peerid
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self.ip = ip
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self.port = port
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self.closed = False
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self.buffer = StringIO()
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self.next_len = 1
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self.next_func = self.read_header_len
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try:
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self.connection = rawserver.start_connection((ip, port), self)
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self.connection.write(chr(len(protocol_name)) + protocol_name +
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(chr(0) * 8) + downloadid)
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except socketerror:
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self.answer(False)
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except IOError:
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self.answer(False)
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def answer(self, result):
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self.closed = True
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try:
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self.connection.close()
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except AttributeError:
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pass
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self.resultfunc(result, self.downloadid, self.peerid, self.ip, self.port)
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def read_header_len(self, s):
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if ord(s) != len(protocol_name):
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return None
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return len(protocol_name), self.read_header
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def read_header(self, s):
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if s != protocol_name:
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return None
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return 8, self.read_reserved
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def read_reserved(self, s):
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return 20, self.read_download_id
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def read_download_id(self, s):
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if s != self.downloadid:
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return None
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return 20, self.read_peer_id
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def read_peer_id(self, s):
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if s != self.peerid:
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return None
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self.answer(True)
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return None
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def data_came_in(self, connection, s):
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while True:
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if self.closed:
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return
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i = self.next_len - self.buffer.tell()
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if i > len(s):
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self.buffer.write(s)
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return
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self.buffer.write(s[:i])
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s = s[i:]
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m = self.buffer.getvalue()
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self.buffer.reset()
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self.buffer.truncate()
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x = self.next_func(m)
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if x is None:
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if not self.closed:
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self.answer(False)
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return
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self.next_len, self.next_func = x
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def connection_lost(self, connection):
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if not self.closed:
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self.closed = True
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self.resultfunc(False, self.downloadid, self.peerid, self.ip, self.port)
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def connection_flushed(self, connection):
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pass
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