34 lines
1.2 KiB
Python
34 lines
1.2 KiB
Python
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from __future__ import annotations
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from typing import List, Tuple
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from pysphinx.sphinx import SphinxPacket
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from protocol.config import GlobalConfig, NodeInfo
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class SphinxPacketBuilder:
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@staticmethod
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def build(
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message: bytes, global_config: GlobalConfig, path_len: int
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) -> Tuple[SphinxPacket, List[NodeInfo]]:
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if path_len <= 0:
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raise ValueError("path_len must be greater than 0")
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if len(message) > global_config.max_message_size:
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raise ValueError("message is too long")
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route = global_config.membership.generate_route(path_len)
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# We don't need the destination (defined in the Loopix Sphinx spec)
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# because the last mix will broadcast the fully unwrapped message.
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# Later, we will optimize the Sphinx according to our requirements.
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dummy_destination = route[-1]
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packet = SphinxPacket.build(
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message,
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route=[mixnode.sphinx_node() for mixnode in route],
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destination=dummy_destination.sphinx_node(),
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max_route_length=global_config.max_mix_path_length,
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max_plain_payload_size=global_config.max_message_size,
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)
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return (packet, route)
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