Bitmessage/PyBitmessage-2025-02-02
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Update class_receiveDataThread.py

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Modified code so that clients send out their inventory lists with the the objects with the most proof of work first. The purpose is to ensure that a small minority of users contributing a relatively low amount of computational resources will not be able to DOS the network because their low proof of work messages are likely to be the last ones delivered and the first ones delayed past object expiration, as discussed here: https://bitmessage.org/forum/index.php?topic=4067.150
This commit is contained in:
a3284642 2014-09-18 22:40:23 +00:00
parent 13db5fe00c
commit 4946600262
1 changed files with 10 additions and 6 deletions
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16
src/class_receiveDataThread.py
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@ -276,15 +276,17 @@ class receiveDataThread(threading.Thread):
# Select all hashes which are younger than two days old and in this
# stream.
queryreturn = sqlQuery(
'''SELECT hash FROM inventory WHERE ((receivedtime>? and objecttype<>'pubkey') or (receivedtime>? and objecttype='pubkey')) and streamnumber=?''',
'''SELECT hash, payload FROM inventory WHERE ((receivedtime>? and objecttype<>'pubkey') or (receivedtime>? and objecttype='pubkey')) and streamnumber=?''',
int(time.time()) - shared.maximumAgeOfObjectsThatIAdvertiseToOthers,
int(time.time()) - shared.lengthOfTimeToHoldOnToAllPubkeys,
self.streamNumber)
bigInvList = {}
for row in queryreturn:
hash, = row
hash, payload = row
if hash not in self.someObjectsOfWhichThisRemoteNodeIsAlreadyAware:
bigInvList[hash] = 0
POW, = unpack('>Q', hashlib.sha512(hashlib.sha512(payload[
:8] + hashlib.sha512(payload[8:]).digest()).digest()).digest()[0:8]) #check POW
bigInvList[hash] = POW
# We also have messages in our inventory in memory (which is a python
# dictionary). Let's fetch those too.
with shared.inventoryLock:
@ -292,12 +294,14 @@ class receiveDataThread(threading.Thread):
if hash not in self.someObjectsOfWhichThisRemoteNodeIsAlreadyAware:
objectType, streamNumber, payload, receivedTime, tag = storedValue
if streamNumber == self.streamNumber and receivedTime > int(time.time()) - shared.maximumAgeOfObjectsThatIAdvertiseToOthers:
bigInvList[hash] = 0
POW, = unpack('>Q', hashlib.sha512(hashlib.sha512(payload[
:8] + hashlib.sha512(payload[8:]).digest()).digest()).digest()[0:8]) #check POW
bigInvList[hash] = POW
numberOfObjectsInInvMessage = 0
payload = ''
# Now let us start appending all of these hashes together. They will be
# sent out in a big inv message to our new peer.
for hash, storedValue in bigInvList.items():
# sent out in a big inv message to our new peer in POW order
for hash in sorted(bigInvList, key=bigInvList.__getitem__):
payload += hash
numberOfObjectsInInvMessage += 1
if numberOfObjectsInInvMessage == 50000: # We can only send a max of 50000 items per inv message but we may have more objects to advertise. They must be split up into multiple inv messages.