53 lines
1.2 KiB
Python
53 lines
1.2 KiB
Python
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from kasten import Kasten
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from time import time
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from math import floor
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MAX_AGE_SECONDS = 60 * 60 * 24 * 30
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MAX_FUTURE_SKEW_SECONDS = 60 * 2
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TOTAL_MAX_SIZE = 6 * (10**6)
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class BlockRulesException(Exception):
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pass
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class BlockOutdated(BlockRulesException):
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pass
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class BlockExpired(Exception):
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pass
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class BlockFutureSkewedBeyondMax(BlockRulesException):
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pass
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class BlockTooLarge(BlockRulesException):
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pass
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def check_block_sanity(raw_bytes):
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kasten: Kasten = Kasten(None, raw_bytes, None, auto_check_generator=False)
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# Ensure a block is not too large
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if len(kasten.get_packed()) > TOTAL_MAX_SIZE:
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raise BlockTooLarge()
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# Ensure block is not future-skewed or expired
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timestamp: int = floor(time())
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block_timestamp = kasten.get_timestamp()
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difference = timestamp - block_timestamp
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if difference > MAX_AGE_SECONDS:
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raise BlockOutdated()
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if difference < -MAX_FUTURE_SKEW_SECONDS:
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raise BlockFutureSkewedBeyondMax()
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try:
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if timestamp < block_timestamp + kasten.get_metadata()[
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'expire']:
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raise BlockExpired()
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except (IndexError, TypeError):
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pass
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