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
  13
  14 class TooLong(Exception):
  15     pass
  16
  17 class Protocol(protocol.Protocol):
  18     def __init__(self, message_prefix, max_payload_length):
  19         self._message_prefix = message_prefix
  20         self._max_payload_length = max_payload_length
  21         self.dataReceived = datachunker.DataChunker(self.dataReceiver())
  22
  23     def dataReceiver(self):
  24         while True:
  25             start = ''
  26             while start != self._message_prefix:
  27                 start = (start + (yield 1))[-len(self._message_prefix):]
  28
  29             command = (yield 12).rstrip('\0')
  30             length, = struct.unpack('<I', (yield 4))
  31             if length > self._max_payload_length:
  32                 print 'length too large'
  33                 continue
  34             checksum = yield 4
  35             payload = yield length
  36
  37             if hashlib.sha256(hashlib.sha256(payload).digest()).digest()[:4] != checksum:
  38                 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')
  39                 continue
  40
  41             type_ = getattr(self, 'message_' + command, None)
  42             if type_ is None:
  43                 if p2pool.DEBUG:
  44                     print 'no type for', repr(command)
  45                 continue
  46
  47             try:
  48                 self.packetReceived(command, type_.unpack(payload))
  49             except:
  50                 print 'RECV', command, payload[:100].encode('hex') + ('...' if len(payload) > 100 else '')
  51                 log.err(None, 'Error handling message: (see RECV line)')
  52                 self.badPeerHappened()
  53
  54     def packetReceived(self, command, payload2):
  55         handler = getattr(self, 'handle_' + command, None)
  56         if handler is None:
  57             if p2pool.DEBUG:
  58                 print 'no handler for', repr(command)
  59             return
  60
  61         handler(**payload2)
  62
  63     def badPeerHappened(self):
  64         self.transport.loseConnection()
  65
  66     def sendPacket(self, command, payload2):
  67         if len(command) >= 12:
  68             raise ValueError('command too long')
  69         type_ = getattr(self, 'message_' + command, None)
  70         if type_ is None:
  71             raise ValueError('invalid command')
  72         #print 'SEND', command, repr(payload2)[:500]
  73         payload = type_.pack(payload2)
  74         if len(payload) > self._max_payload_length:
  75             raise TooLong('payload too long')
  76         self.transport.write(self._message_prefix + struct.pack('<12sI', command, len(payload)) + hashlib.sha256(hashlib.sha256(payload).digest()).digest()[:4] + payload)
  77
  78     def __getattr__(self, attr):
  79         prefix = 'send_'
  80         if attr.startswith(prefix):
  81             command = attr[len(prefix):]
  82             return lambda **payload2: self.sendPacket(command, payload2)
  83         #return protocol.Protocol.__getattr__(self, attr)
  84         raise AttributeError(attr)