PyBitmessage/src/network/bmobject.py

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from binascii import hexlify
import time
from addresses import calculateInventoryHash
from debug import logger
from inventory import Inventory
from network.dandelion import DandelionStems
import protocol
import state
class BMObjectInsufficientPOWError(Exception): pass
class BMObjectInvalidDataError(Exception): pass
class BMObjectExpiredError(Exception): pass
class BMObjectUnwantedStreamError(Exception): pass
class BMObjectInvalidError(Exception): pass
class BMObjectAlreadyHaveError(Exception):
pass
class BMObject(object):
# max TTL, 28 days and 3 hours
maxTTL = 28 * 24 * 60 * 60 + 10800
# min TTL, 3 hour (in the past
minTTL = -3600
def __init__(self, nonce, expiresTime, objectType, version, streamNumber, data, payloadOffset):
self.nonce = nonce
self.expiresTime = expiresTime
self.objectType = objectType
self.version = version
self.streamNumber = streamNumber
self.inventoryHash = calculateInventoryHash(data)
self.data = data
self.tag = data[payloadOffset:payloadOffset+32]
def checkProofOfWorkSufficient(self):
# Let us check to make sure that the proof of work is sufficient.
if not protocol.isProofOfWorkSufficient(self.data):
logger.info('Proof of work is insufficient.')
raise BMObjectInsufficientPOWError()
def checkEOLSanity(self):
# EOL sanity check
if self.expiresTime - int(time.time()) > BMObject.maxTTL:
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logger.info('This object\'s End of Life time is too far in the future. Ignoring it. Time is %i', self.expiresTime)
# TODO: remove from download queue
raise BMObjectExpiredError()
if self.expiresTime - int(time.time()) < BMObject.minTTL:
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logger.info('This object\'s End of Life time was too long ago. Ignoring the object. Time is %i', self.expiresTime)
# TODO: remove from download queue
raise BMObjectExpiredError()
def checkStream(self):
if self.streamNumber not in state.streamsInWhichIAmParticipating:
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logger.debug('The streamNumber %i isn\'t one we are interested in.', self.streamNumber)
raise BMObjectUnwantedStreamError()
def checkAlreadyHave(self):
# if it's a stem duplicate, pretend we don't have it
if self.inventoryHash in DandelionStems().stem:
return
if self.inventoryHash in Inventory():
raise BMObjectAlreadyHaveError()
def checkObjectByType(self):
if self.objectType == protocol.OBJECT_GETPUBKEY:
self.checkGetpubkey()
elif self.objectType == protocol.OBJECT_PUBKEY:
self.checkPubkey()
elif self.objectType == protocol.OBJECT_MSG:
self.checkMessage()
elif self.objectType == protocol.OBJECT_BROADCAST:
self.checkBroadcast()
# other objects don't require other types of tests
def checkMessage(self):
return
def checkGetpubkey(self):
if len(self.data) < 42:
logger.info('getpubkey message doesn\'t contain enough data. Ignoring.')
raise BMObjectInvalidError()
def checkPubkey(self):
if len(self.data) < 146 or len(self.data) > 440: # sanity check
logger.info('pubkey object too short or too long. Ignoring.')
raise BMObjectInvalidError()
def checkBroadcast(self):
if len(self.data) < 180:
logger.debug('The payload length of this broadcast packet is unreasonably low. Someone is probably trying funny business. Ignoring message.')
raise BMObjectInvalidError()
# this isn't supported anymore
if self.version < 2:
raise BMObjectInvalidError()