1  """
  2  BMObject and it's exceptions.
  3  """
  4  import logging
  5  import time
  6  
  7  import protocol
  8  import state
  9  from network import dandelion_ins
 10  from highlevelcrypto import calculateInventoryHash
 11  
 12  logger = logging.getLogger('default')
 13  
 14  
 15  class BMObjectInsufficientPOWError(Exception):
 16      """Exception indicating the object
 17      doesn't have sufficient proof of work."""
 18      errorCodes = ("Insufficient proof of work")
 19  
 20  
 21  class BMObjectExpiredError(Exception):
 22      """Exception indicating the object's lifetime has expired."""
 23      errorCodes = ("Object expired")
 24  
 25  
 26  class BMObjectUnwantedStreamError(Exception):
 27      """Exception indicating the object is in a stream
 28      we didn't advertise as being interested in."""
 29      errorCodes = ("Object in unwanted stream")
 30  
 31  
 32  class BMObjectInvalidError(Exception):
 33      """The object's data does not match object specification."""
 34      errorCodes = ("Invalid object")
 35  
 36  
 37  class BMObjectAlreadyHaveError(Exception):
 38      """We received a duplicate object (one we already have)"""
 39      errorCodes = ("Already have this object")
 40  
 41  
 42  class BMObject(object):
 43      """Bitmessage Object as a class."""
 44  
 45      # max TTL, 28 days and 3 hours
 46      maxTTL = 28 * 24 * 60 * 60 + 10800
 47      # min TTL, 3 hour (in the past
 48      minTTL = -3600
 49  
 50      def __init__(
 51              self,
 52              nonce,
 53              expiresTime,
 54              objectType,
 55              version,
 56              streamNumber,
 57              data,
 58              payloadOffset
 59      ):
 60          self.nonce = nonce
 61          self.expiresTime = expiresTime
 62          self.objectType = objectType
 63          self.version = version
 64          self.streamNumber = streamNumber
 65          self.inventoryHash = calculateInventoryHash(data)
 66          # copy to avoid memory issues
 67          self.data = bytearray(data)
 68          self.tag = self.data[payloadOffset:payloadOffset + 32]
 69  
 70      def checkProofOfWorkSufficient(self):
 71          """Perform a proof of work check for sufficiency."""
 72          # Let us check to make sure that the proof of work is sufficient.
 73          if not protocol.isProofOfWorkSufficient(self.data):
 74              logger.info('Proof of work is insufficient.')
 75              raise BMObjectInsufficientPOWError()
 76  
 77      def checkEOLSanity(self):
 78          """Check if object's lifetime
 79          isn't ridiculously far in the past or future."""
 80          # EOL sanity check
 81          if self.expiresTime - int(time.time()) > BMObject.maxTTL:
 82              logger.info(
 83                  'This object\'s End of Life time is too far in the future.'
 84                  ' Ignoring it. Time is %i', self.expiresTime)
 85              # .. todo::  remove from download queue
 86              raise BMObjectExpiredError()
 87  
 88          if self.expiresTime - int(time.time()) < BMObject.minTTL:
 89              logger.info(
 90                  'This object\'s End of Life time was too long ago.'
 91                  ' Ignoring the object. Time is %i', self.expiresTime)
 92              # .. todo::  remove from download queue
 93              raise BMObjectExpiredError()
 94  
 95      def checkStream(self):
 96          import connectionpool
 97          """Check if object's stream matches streams we are interested in"""
 98          if self.streamNumber < protocol.MIN_VALID_STREAM \
 99             or self.streamNumber > protocol.MAX_VALID_STREAM:
100              logger.warning(
101                  'The object has invalid stream: %s', self.streamNumber)
102              raise BMObjectInvalidError()
103          if self.streamNumber not in connectionpool.pool.streams:
104              logger.debug(
105                  'The streamNumber %i isn\'t one we are interested in.',
106                  self.streamNumber)
107              raise BMObjectUnwantedStreamError()
108  
109      def checkAlreadyHave(self):
110          """
111          Check if we already have the object
112          (so that we don't duplicate it in inventory
113          or advertise it unnecessarily)
114          """
115          # if it's a stem duplicate, pretend we don't have it
116          if dandelion_ins.hasHash(self.inventoryHash):
117              return
118          if self.inventoryHash in state.Inventory:
119              raise BMObjectAlreadyHaveError()
120  
121      def checkObjectByType(self):
122          """Call a object type specific check
123          (objects can have additional checks based on their types)"""
124          if self.objectType == protocol.OBJECT_GETPUBKEY:
125              self.checkGetpubkey()
126          elif self.objectType == protocol.OBJECT_PUBKEY:
127              self.checkPubkey()
128          elif self.objectType == protocol.OBJECT_MSG:
129              self.checkMessage()
130          elif self.objectType == protocol.OBJECT_BROADCAST:
131              self.checkBroadcast()
132          # other objects don't require other types of tests
133  
134      def checkMessage(self):  # pylint: disable=no-self-use
135          """"Message" object type checks."""
136          return
137  
138      def checkGetpubkey(self):
139          """"Getpubkey" object type checks."""
140          if len(self.data) < 42:
141              logger.info(
142                  'getpubkey message doesn\'t contain enough data. Ignoring.')
143              raise BMObjectInvalidError()
144  
145      def checkPubkey(self):
146          """"Pubkey" object type checks."""
147          # sanity check
148          if len(self.data) < 146 or len(self.data) > 440:
149              logger.info('pubkey object too short or too long. Ignoring.')
150              raise BMObjectInvalidError()
151  
152      def checkBroadcast(self):
153          """"Broadcast" object type checks."""
154          if len(self.data) < 180:
155              logger.debug(
156                  'The payload length of this broadcast'
157                  ' packet is unreasonably low. Someone is probably'
158                  ' trying funny business. Ignoring message.')
159              raise BMObjectInvalidError()
160  
161          # this isn't supported anymore
162          if self.version < 2:
163              raise BMObjectInvalidError()