1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
|
# The contents of this file are subject to the BitTorrent Open Source License
# Version 1.1 (the License). You may not copy or use this file, in either
# source code or executable form, except in compliance with the License. You
# may obtain a copy of the License at http://www.bittorrent.com/license/.
#
# Software distributed under the License is distributed on an AS IS basis,
# WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
# for the specific language governing rights and limitations under the
# License.
# Written by Bram Cohen
from cStringIO import StringIO
from socket import error as socketerror
protocol_name = 'BitTorrent protocol'
# header, reserved, download id, my id, [length, message]
from twisted.internet.protocol import Protocol, ClientFactory
from twisted.internet import reactor
from twisted.python import log
class NatCheck(object):
def __init__(self, resultfunc, downloadid, peerid, ip, port):
self.resultfunc = resultfunc
self.downloadid = downloadid
self.peerid = peerid
self.ip = ip
self.port = port
self.answered = False
factory = NatCheckProtocolFactory(self, downloadid, peerid)
reactor.connectTCP(ip, port, factory)
def answer(self, result):
if not self.answered:
self.answered = True
log.msg('NAT check for %s:%i is %s' % (self.ip, self.port, result))
self.resultfunc(result, self.downloadid, self.peerid, self.ip, self.port)
class NatCheckProtocolFactory(ClientFactory):
def __init__(self, natcheck, downloadid, peerid):
self.natcheck = natcheck
self.downloadid = downloadid
self.peerid = peerid
def startedConnecting(self, connector):
log.msg('Started to connect.')
def buildProtocol(self, addr):
return NatCheckProtocol(self, self.downloadid, self.peerid)
def clientConnectionLost(self, connector, reason):
self.natcheck.answer(False)
log.msg('Lost connection. Reason: %s' % reason)
def clientConnectionFailed(self, connector, reason):
self.natcheck.answer(False)
log.msg('Connection failed. Reason: %s' % reason)
class NatCheckProtocol(Protocol):
def __init__(self, factory, downloadid, peerid):
self.factory = factory
self.downloadid = downloadid
self.peerid = peerid
self.data = ''
self.received_protocol_name_len = None
self.received_protocol_name = None
self.received_reserved = None
self.received_downloadid = None
self.received_peerid = None
def connectionMade(self):
self.transport.write(chr(len(protocol_name)))
self.transport.write(protocol_name)
self.transport.write(chr(0) * 8)
self.transport.write(self.downloadid)
def dataReceived(self, data):
self.data += data
if self.received_protocol_name_len is None:
if len(self.data) >= 1:
self.received_protocol_name_len = ord(self.data[0])
self.data = self.data[1:]
if self.received_protocol_name_len != len(protocol_name):
self.factory.natcheck.answer(False)
self.transport.loseConnection()
return
else:
return
if self.received_protocol_name is None:
if len(self.data) >= self.received_protocol_name_len:
self.received_protocol_name = self.data[:self.received_protocol_name_len]
self.data = self.data[self.received_protocol_name_len:]
if self.received_protocol_name != protocol_name:
log.err('Received protocol name did not match!')
self.factory.natcheck.answer(False)
self.transport.loseConnection()
return
else:
return
if self.received_reserved is None:
if len(self.data) >= 8:
self.received_reserved = self.data[:8]
self.data = self.data[8:]
else:
return
if self.received_downloadid is None:
if len(self.data) >= 20:
self.received_downloadid = self.data[:20]
self.data = self.data[20:]
if self.received_downloadid != self.downloadid:
log.err('Received download id did not match!')
self.factory.natcheck.answer(False)
self.transport.loseConnection()
return
else:
return
if self.received_peerid is None:
if len(self.data) >= 20:
log.msg('Peerid length: %i' % len(self.peerid))
self.received_peerid = self.data[:20]
self.data = self.data[20:]
log.msg('Received: %s' % self.received_peerid.encode('hex'))
log.msg('Received: %s' % self.received_peerid.encode('quoted-printable'))
log.msg('Expected: %s' % self.peerid.encode('hex'))
log.msg('Expected: %s' % self.peerid.encode('quoted-printable'))
if self.received_peerid != self.peerid:
log.err('Received peer id did not match!')
self.factory.natcheck.answer(False)
self.transport.loseConnection()
return
else:
return
if self.received_protocol_name == protocol_name and self.received_downloadid == self.downloadid and self.received_peerid == self.peerid:
self.factory.natcheck.answer(True)
self.transport.loseConnection()
|
