268 lines
7.8 KiB
Python
268 lines
7.8 KiB
Python
# -*- coding: utf-8 -*-
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"""Protocol message objects"""
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import base64
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import hashlib
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import struct
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import time
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from . import shared, structure
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class Header():
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"""Message header structure"""
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def __init__(self, command, payload_length, payload_checksum):
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self.command = command
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self.payload_length = payload_length
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self.payload_checksum = payload_checksum
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def __repr__(self):
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return (
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'type: header, command: "{}", payload_length: {},'
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' payload_checksum: {}'
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).format(
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self.command.decode(), self.payload_length,
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base64.b16encode(self.payload_checksum).decode())
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def to_bytes(self):
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"""Serialize to bytes"""
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b = b''
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b += shared.magic_bytes
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b += self.command.ljust(12, b'\x00')
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b += struct.pack('>L', self.payload_length)
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b += self.payload_checksum
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return b
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@classmethod
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def from_bytes(cls, b):
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"""Parse from bytes"""
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magic_bytes, command, payload_length, payload_checksum = struct.unpack(
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'>4s12sL4s', b)
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if magic_bytes != shared.magic_bytes:
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raise ValueError('magic_bytes do not match')
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command = command.rstrip(b'\x00')
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return cls(command, payload_length, payload_checksum)
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class Message():
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"""Common message structure"""
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def __init__(self, command, payload):
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self.command = command
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self.payload = payload
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self.payload_length = len(payload)
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self.payload_checksum = hashlib.sha512(payload).digest()[:4]
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def __repr__(self):
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return '{}, payload_length: {}, payload_checksum: {}'.format(
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self.command.decode(), self.payload_length,
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base64.b16encode(self.payload_checksum).decode())
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def to_bytes(self):
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"""Serialize to bytes"""
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b = Header(
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self.command, self.payload_length, self.payload_checksum
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).to_bytes()
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b += self.payload
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return b
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@classmethod
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def from_bytes(cls, b):
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"""Parse from bytes"""
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h = Header.from_bytes(b[:24])
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payload = b[24:]
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payload_length = len(payload)
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if payload_length != h.payload_length:
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raise ValueError(
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'wrong payload length, expected {}, got {}'.format(
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h.payload_length, payload_length))
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payload_checksum = hashlib.sha512(payload).digest()[:4]
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if payload_checksum != h.payload_checksum:
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raise ValueError(
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'wrong payload checksum, expected {}, got {}'.format(
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h.payload_checksum, payload_checksum))
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return cls(h.command, payload)
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class Version():
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"""The version message payload"""
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def __init__(
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self, host, port, protocol_version=shared.protocol_version,
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services=shared.services, nonce=shared.nonce,
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user_agent=shared.user_agent
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):
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self.host = host
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self.port = port
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self.protocol_version = protocol_version
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self.services = services
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self.nonce = nonce
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self.user_agent = user_agent
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def __repr__(self):
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return (
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'version, protocol_version: {}, services: {}, host: {}, port: {},'
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' nonce: {}, user_agent: {}').format(
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self.protocol_version, self.services, self.host, self.port,
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base64.b16encode(self.nonce).decode(), self.user_agent)
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def to_bytes(self):
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payload = b''
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payload += struct.pack('>I', self.protocol_version)
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payload += struct.pack('>Q', self.services)
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payload += struct.pack('>Q', int(time.time()))
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payload += structure.NetAddrNoPrefix(
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shared.services, self.host, self.port).to_bytes()
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payload += structure.NetAddrNoPrefix(
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shared.services, '127.0.0.1', 8444).to_bytes()
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payload += self.nonce
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payload += structure.VarInt(len(shared.user_agent)).to_bytes()
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payload += shared.user_agent
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payload += 2 * structure.VarInt(1).to_bytes()
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return Message(b'version', payload).to_bytes()
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@classmethod
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def from_bytes(cls, b):
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m = Message.from_bytes(b)
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payload = m.payload
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( # unused: timestamp, net_addr_local
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protocol_version, services, _, net_addr_remote, _, nonce
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) = struct.unpack('>IQQ26s26s8s', payload[:80])
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net_addr_remote = structure.NetAddrNoPrefix.from_bytes(net_addr_remote)
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host = net_addr_remote.host
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port = net_addr_remote.port
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payload = payload[80:]
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user_agent_varint_length = structure.VarInt.length(payload[0])
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user_agent_length = structure.VarInt.from_bytes(
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payload[:user_agent_varint_length]).n
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payload = payload[user_agent_varint_length:]
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user_agent = payload[:user_agent_length]
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payload = payload[user_agent_length:]
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if payload != b'\x01\x01':
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raise ValueError('message not for stream 1')
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return cls(host, port, protocol_version, services, nonce, user_agent)
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class Inv():
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"""The inv message payload"""
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def __init__(self, vectors):
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self.vectors = set(vectors)
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def __repr__(self):
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return 'inv, count: {}'.format(len(self.vectors))
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def to_bytes(self):
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return Message(
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b'inv', structure.VarInt(len(self.vectors)).to_bytes()
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+ b''.join(self.vectors)
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).to_bytes()
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@classmethod
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def from_message(cls, m):
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payload = m.payload
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vector_count_varint_length = structure.VarInt.length(payload[0])
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vector_count = structure.VarInt.from_bytes(
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payload[:vector_count_varint_length]).n
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payload = payload[vector_count_varint_length:]
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vectors = set()
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while payload:
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vectors.add(payload[:32])
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payload = payload[32:]
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if vector_count != len(vectors):
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raise ValueError('malformed Inv message, wrong vector_count')
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return cls(vectors)
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class GetData():
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"""The getdata message payload"""
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def __init__(self, vectors):
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self.vectors = set(vectors)
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def __repr__(self):
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return 'getdata, count: {}'.format(len(self.vectors))
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def to_bytes(self):
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return Message(
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b'getdata', structure.VarInt(len(self.vectors)).to_bytes()
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+ b''.join(self.vectors)
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).to_bytes()
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@classmethod
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def from_message(cls, m):
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payload = m.payload
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vector_count_varint_length = structure.VarInt.length(payload[0])
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vector_count = structure.VarInt.from_bytes(
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payload[:vector_count_varint_length]).n
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payload = payload[vector_count_varint_length:]
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vectors = set()
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while payload:
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vectors.add(payload[:32])
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payload = payload[32:]
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if vector_count != len(vectors):
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raise ValueError('malformed GetData message, wrong vector_count')
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return cls(vectors)
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class Addr():
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"""The addr message payload"""
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def __init__(self, addresses):
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self.addresses = addresses
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def __repr__(self):
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return 'addr, count: {}'.format(len(self.addresses))
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def to_bytes(self):
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return Message(
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b'addr', structure.VarInt(len(self.addresses)).to_bytes()
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+ b''.join({addr.to_bytes() for addr in self.addresses})
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).to_bytes()
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@classmethod
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def from_message(cls, m):
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payload = m.payload
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addr_count_varint_length = structure.VarInt.length(payload[0])
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# addr_count = structure.VarInt.from_bytes(
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# payload[:addr_count_varint_length]).n
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payload = payload[addr_count_varint_length:]
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addresses = set()
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while payload:
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addresses.add(structure.NetAddr.from_bytes(payload[:38]))
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payload = payload[38:]
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return cls(addresses)
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