p2pool/util/p2protocol.py

   1 '''
   2 Generic message-based protocol used by Bitcoin and P2Pool for P2P communication
   3 '''
   4
   5 import hashlib
   6 import struct
   7
   8 from twisted.internet import protocol
   9 from twisted.python import log
  10
  11 import p2pool
  12 from p2pool.util import datachunker, variable
  13
  14 class TooLong(Exception):
  15     pass
  16
  17 class Protocol(protocol.Protocol):
  18     def __init__(self, message_prefix, max_payload_length, traffic_happened=variable.Event()):
  19         self._message_prefix = message_prefix
  20         self._max_payload_length = max_payload_length
  21         self.dataReceived2 = datachunker.DataChunker(self.dataReceiver())
  22         self.traffic_happened = traffic_happened
  23
  24     def dataReceived(self, data):
  25         self.traffic_happened.happened('p2p/in', len(data))
  26         self.dataReceived2(data)
  27
  28     def dataReceiver(self):
  29         while True:
  30             start = ''
  31             while start != self._message_prefix:
  32                 start = (start + (yield 1))[-len(self._message_prefix):]
  33
  34             command = (yield 12).rstrip('\0')
  35             length, = struct.unpack('<I', (yield 4))
  36             if length > self._max_payload_length:
  37                 print 'length too large'
  38                 continue
  39             checksum = yield 4
  40             payload = yield length
  41
  42             if hashlib.sha256(hashlib.sha256(payload).digest()).digest()[:4] != checksum:
  43                 print 'invalid hash for', self.transport.getPeer().host, repr(command), length, checksum.encode('hex'), hashlib.sha256(hashlib.sha256(payload).digest()).digest()[:4].encode('hex'), payload.encode('hex')
  44                 self.badPeerHappened()
  45                 continue
  46
  47             type_ = getattr(self, 'message_' + command, None)
  48             if type_ is None:
  49                 if p2pool.DEBUG:
  50                     print 'no type for', repr(command)
  51                 continue
  52
  53             try:
  54                 self.packetReceived(command, type_.unpack(payload))
  55             except:
  56                 print 'RECV', command, payload[:100].encode('hex') + ('...' if len(payload) > 100 else '')
  57                 log.err(None, 'Error handling message: (see RECV line)')
  58                 self.transport.loseConnection()
  59
  60     def packetReceived(self, command, payload2):
  61         handler = getattr(self, 'handle_' + command, None)
  62         if handler is None:
  63             if p2pool.DEBUG:
  64                 print 'no handler for', repr(command)
  65             return
  66
  67         if getattr(self, 'connected', True) and not getattr(self, 'disconnecting', False):
  68             handler(**payload2)
  69
  70     def badPeerHappened(self):
  71         self.transport.loseConnection()
  72
  73     def sendPacket(self, command, payload2):
  74         if len(command) >= 12:
  75             raise ValueError('command too long')
  76         type_ = getattr(self, 'message_' + command, None)
  77         if type_ is None:
  78             raise ValueError('invalid command')
  79         #print 'SEND', command, repr(payload2)[:500]
  80         payload = type_.pack(payload2)
  81         if len(payload) > self._max_payload_length:
  82             raise TooLong('payload too long')
  83         data = self._message_prefix + struct.pack('<12sI', command, len(payload)) + hashlib.sha256(hashlib.sha256(payload).digest()).digest()[:4] + payload
  84         self.traffic_happened.happened('p2p/out', len(data))
  85         self.transport.write(data)
  86
  87     def __getattr__(self, attr):
  88         prefix = 'send_'
  89         if attr.startswith(prefix):
  90             command = attr[len(prefix):]
  91             return lambda **payload2: self.sendPacket(command, payload2)
  92         #return protocol.Protocol.__getattr__(self, attr)
  93         raise AttributeError(attr)