PyBitmessage-2021-04-27/src/network/bmobject.py
2020-01-10 16:51:17 +05:30

165 lines
5.5 KiB
Python

"""
BMObject and it's exceptions.
"""
import logging
import time
import protocol
import state
from addresses import calculateInventoryHash
from inventory import Inventory
from network.dandelion import Dandelion
logger = logging.getLogger('default')
class BMObjectInsufficientPOWError(Exception):
"""Exception indicating the object
doesn't have sufficient proof of work."""
errorCodes = ("Insufficient proof of work")
class BMObjectInvalidDataError(Exception):
"""Exception indicating the data being parsed
does not match the specification."""
errorCodes = ("Data invalid")
class BMObjectExpiredError(Exception):
"""Exception indicating the object's lifetime has expired."""
errorCodes = ("Object expired")
class BMObjectUnwantedStreamError(Exception):
"""Exception indicating the object is in a stream
we didn't advertise as being interested in."""
errorCodes = ("Object in unwanted stream")
class BMObjectInvalidError(Exception):
"""The object's data does not match object specification."""
errorCodes = ("Invalid object")
class BMObjectAlreadyHaveError(Exception):
"""We received a duplicate object (one we already have)"""
errorCodes = ("Already have this object")
class BMObject(object): # pylint: disable=too-many-instance-attributes
"""Bitmessage Object as a class."""
# 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
): # pylint: disable=too-many-arguments
self.nonce = nonce
self.expiresTime = expiresTime
self.objectType = objectType
self.version = version
self.streamNumber = streamNumber
self.inventoryHash = calculateInventoryHash(data)
# copy to avoid memory issues
self.data = bytearray(data)
self.tag = self.data[payloadOffset:payloadOffset + 32]
def checkProofOfWorkSufficient(self):
"""Perform a proof of work check for sufficiency."""
# 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):
"""Check if object's lifetime
isn't ridiculously far in the past or future."""
# EOL sanity check
if self.expiresTime - int(time.time()) > BMObject.maxTTL:
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:
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):
"""Check if object's stream matches streams we are interested in"""
if self.streamNumber not in state.streamsInWhichIAmParticipating:
logger.debug(
'The streamNumber %i isn\'t one we are interested in.',
self.streamNumber)
raise BMObjectUnwantedStreamError()
def checkAlreadyHave(self):
"""
Check if we already have the object
(so that we don't duplicate it in inventory
or advertise it unnecessarily)
"""
# if it's a stem duplicate, pretend we don't have it
if Dandelion().hasHash(self.inventoryHash):
return
if self.inventoryHash in Inventory():
raise BMObjectAlreadyHaveError()
def checkObjectByType(self):
"""Call a object type specific check
(objects can have additional checks based on their types)"""
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): # pylint: disable=no-self-use
""""Message" object type checks."""
return
def checkGetpubkey(self):
""""Getpubkey" object type checks."""
if len(self.data) < 42:
logger.info(
'getpubkey message doesn\'t contain enough data. Ignoring.')
raise BMObjectInvalidError()
def checkPubkey(self):
""""Pubkey" object type checks."""
# sanity check
if len(self.data) < 146 or len(self.data) > 440:
logger.info('pubkey object too short or too long. Ignoring.')
raise BMObjectInvalidError()
def checkBroadcast(self):
""""Broadcast" object type checks."""
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()