MiNode/minode/message.py

321 lines
9.4 KiB
Python

# -*- coding: utf-8 -*-
"""Protocol message objects"""
import base64
import hashlib
import struct
import time
from abc import ABC, abstractmethod
from . import shared, structure
class IMessage(ABC):
"""A base for typical message"""
@abstractmethod
def __repr__(self):
"""Make a printable form"""
@abstractmethod
def to_bytes(self):
"""Serialize to bytes the full message"""
@classmethod
@abstractmethod
def from_message(cls, m):
"""Parse from message"""
class Header(structure.IStructure):
"""Message header structure"""
def __init__(self, command, payload_length, payload_checksum):
self.command = command
self.payload_length = payload_length
self.payload_checksum = payload_checksum
def __repr__(self):
return (
'type: header, command: "{}", payload_length: {},'
' payload_checksum: {}'
).format(
self.command.decode(), self.payload_length,
base64.b16encode(self.payload_checksum).decode())
def to_bytes(self):
b = b''
b += shared.magic_bytes
b += self.command.ljust(12, b'\x00')
b += struct.pack('>L', self.payload_length)
b += self.payload_checksum
return b
@classmethod
def from_bytes(cls, b):
magic_bytes, command, payload_length, payload_checksum = struct.unpack(
'>4s12sL4s', b)
if magic_bytes != shared.magic_bytes:
raise ValueError('magic_bytes do not match')
command = command.rstrip(b'\x00')
return cls(command, payload_length, payload_checksum)
class Message(structure.IStructure):
"""Common message structure"""
def __init__(self, command, payload):
self.command = command
self.payload = payload
self.payload_length = len(payload)
self.payload_checksum = hashlib.sha512(payload).digest()[:4]
def __repr__(self):
return '{}, payload_length: {}, payload_checksum: {}'.format(
self.command.decode(), self.payload_length,
base64.b16encode(self.payload_checksum).decode())
def to_bytes(self):
b = Header(
self.command, self.payload_length, self.payload_checksum
).to_bytes()
b += self.payload
return b
@classmethod
def from_bytes(cls, b):
h = Header.from_bytes(b[:24])
payload = b[24:]
payload_length = len(payload)
if payload_length != h.payload_length:
raise ValueError(
'wrong payload length, expected {}, got {}'.format(
h.payload_length, payload_length))
payload_checksum = hashlib.sha512(payload).digest()[:4]
if payload_checksum != h.payload_checksum:
raise ValueError(
'wrong payload checksum, expected {}, got {}'.format(
h.payload_checksum, payload_checksum))
return cls(h.command, payload)
def _payload_read_int(data):
varint_length = structure.VarInt.length(data[0])
return (
structure.VarInt.from_bytes(data[:varint_length]).n,
data[varint_length:])
class Version(IMessage):
"""The version message payload"""
def __init__(
self, host, port, protocol_version=shared.protocol_version,
services=shared.services, nonce=shared.nonce,
user_agent=shared.user_agent, streams=None
):
self.host = host
self.port = port
self.protocol_version = protocol_version
self.services = services
self.nonce = nonce
self.user_agent = user_agent
self.streams = streams or [shared.stream]
if len(self.streams) > 160000:
self.streams = self.streams[:160000]
def __repr__(self):
return (
'version, protocol_version: {}, services: {}, host: {}, port: {},'
' nonce: {}, user_agent: {}').format(
self.protocol_version, self.services, self.host, self.port,
base64.b16encode(self.nonce).decode(), self.user_agent)
def to_bytes(self):
payload = b''
payload += struct.pack('>I', self.protocol_version)
payload += struct.pack('>Q', self.services)
payload += struct.pack('>Q', int(time.time()))
payload += structure.NetAddrNoPrefix(
1, self.host, self.port).to_bytes()
payload += structure.NetAddrNoPrefix(
self.services, '127.0.0.1', 8444).to_bytes()
payload += self.nonce
payload += structure.VarInt(len(self.user_agent)).to_bytes()
payload += self.user_agent
payload += structure.VarInt(len(self.streams)).to_bytes()
for stream in self.streams:
payload += structure.VarInt(stream).to_bytes()
return Message(b'version', payload).to_bytes()
@classmethod
def from_message(cls, m):
payload = m.payload
( # unused: net_addr_local
protocol_version, services, timestamp, net_addr_remote, _, nonce
) = struct.unpack('>IQQ26s26s8s', payload[:80])
if abs(time.time() - timestamp) > 3600:
raise ValueError('remote time offset is too large')
net_addr_remote = structure.NetAddrNoPrefix.from_bytes(net_addr_remote)
host = net_addr_remote.host
port = net_addr_remote.port
payload = payload[80:]
user_agent_length, payload = _payload_read_int(payload)
user_agent = payload[:user_agent_length]
payload = payload[user_agent_length:]
streams_count, payload = _payload_read_int(payload)
if streams_count > 160000:
raise ValueError('malformed Version message, to many streams')
streams = []
while payload:
stream, payload = _payload_read_int(payload)
streams.append(stream)
if streams_count != len(streams):
raise ValueError('malformed Version message, wrong streams_count')
return cls(
host, port, protocol_version, services, nonce, user_agent, streams)
class Inv(IMessage):
"""The inv message payload"""
def __init__(self, vectors):
self.vectors = set(vectors)
def __repr__(self):
return 'inv, count: {}'.format(len(self.vectors))
def to_bytes(self):
return Message(
b'inv', structure.VarInt(len(self.vectors)).to_bytes()
+ b''.join(self.vectors)
).to_bytes()
@classmethod
def from_message(cls, m):
payload = m.payload
vector_count, payload = _payload_read_int(payload)
vectors = set()
while payload:
vectors.add(payload[:32])
payload = payload[32:]
if vector_count != len(vectors):
raise ValueError('malformed Inv message, wrong vector_count')
return cls(vectors)
class GetData(IMessage):
"""The getdata message payload"""
def __init__(self, vectors):
self.vectors = set(vectors)
def __repr__(self):
return 'getdata, count: {}'.format(len(self.vectors))
def to_bytes(self):
return Message(
b'getdata', structure.VarInt(len(self.vectors)).to_bytes()
+ b''.join(self.vectors)
).to_bytes()
@classmethod
def from_message(cls, m):
payload = m.payload
vector_count, payload = _payload_read_int(payload)
vectors = set()
while payload:
vectors.add(payload[:32])
payload = payload[32:]
if vector_count != len(vectors):
raise ValueError('malformed GetData message, wrong vector_count')
return cls(vectors)
class Addr(IMessage):
"""The addr message payload"""
def __init__(self, addresses):
self.addresses = addresses
def __repr__(self):
return 'addr, count: {}'.format(len(self.addresses))
def to_bytes(self):
return Message(
b'addr', structure.VarInt(len(self.addresses)).to_bytes()
+ b''.join({addr.to_bytes() for addr in self.addresses})
).to_bytes()
@classmethod
def from_message(cls, m):
payload = m.payload
# not validating addr_count
_, payload = _payload_read_int(payload)
addresses = set()
while payload:
addresses.add(structure.NetAddr.from_bytes(payload[:38]))
payload = payload[38:]
return cls(addresses)
class Error(IMessage):
"""The error message payload"""
def __init__(self, error_text=b'', fatal=0, ban_time=0, vector=b''):
self.error_text = error_text
self.fatal = fatal
self.ban_time = ban_time
self.vector = vector
def __repr__(self):
return 'error, text: {}'.format(self.error_text)
def to_bytes(self):
return Message(
b'error', structure.VarInt(self.fatal).to_bytes()
+ structure.VarInt(self.ban_time).to_bytes()
+ structure.VarInt(len(self.vector)).to_bytes() + self.vector
+ structure.VarInt(len(self.error_text)).to_bytes()
+ self.error_text
).to_bytes()
@classmethod
def from_message(cls, m):
payload = m.payload
fatal, payload = _payload_read_int(payload)
ban_time, payload = _payload_read_int(payload)
vector_length, payload = _payload_read_int(payload)
vector = payload[:vector_length]
payload = payload[vector_length:]
error_text_length, payload = _payload_read_int(payload)
error_text = payload[:error_text_length]
return cls(error_text, fatal, ban_time, vector)