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network dns hacks: split from network.py into its own file

hard-fail-on-bad-server-string
SomberNight 5 years ago
committed by ghost43
parent
cb88a3b6e4
commit
11452722af
2 changed files with 103 additions and 74 deletions
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  1. 100
      electrum/dns_hacks.py
  2. 77
      electrum/network.py

100
electrum/dns_hacks.py
View File

@ -0,0 +1,100 @@
# Copyright (C) 2020 The Electrum developers
# Distributed under the MIT software license, see the accompanying
# file LICENCE or http://www.opensource.org/licenses/mit-license.php
import sys
import socket
import concurrent
from concurrent import futures
import ipaddress
from typing import Optional
import dns
import dns.resolver
from .logging import get_logger
_logger = get_logger(__name__)
_dns_threads_executor = None # type: Optional[concurrent.futures.Executor]
def configure_dns_depending_on_proxy(is_proxy: bool) -> None:
# Store this somewhere so we can un-monkey-patch:
if not hasattr(socket, "_getaddrinfo"):
socket._getaddrinfo = socket.getaddrinfo
if is_proxy:
# prevent dns leaks, see http://stackoverflow.com/questions/13184205/dns-over-proxy
socket.getaddrinfo = lambda *args: [(socket.AF_INET, socket.SOCK_STREAM, 6, '', (args[0], args[1]))]
else:
if sys.platform == 'win32':
# On Windows, socket.getaddrinfo takes a mutex, and might hold it for up to 10 seconds
# when dns-resolving. To speed it up drastically, we resolve dns ourselves, outside that lock.
# See https://github.com/spesmilo/electrum/issues/4421
_prepare_windows_dns_hack()
socket.getaddrinfo = _fast_getaddrinfo
else:
socket.getaddrinfo = socket._getaddrinfo
def _prepare_windows_dns_hack():
# enable dns cache
resolver = dns.resolver.get_default_resolver()
if resolver.cache is None:
resolver.cache = dns.resolver.Cache()
# prepare threads
global _dns_threads_executor
if _dns_threads_executor is None:
_dns_threads_executor = concurrent.futures.ThreadPoolExecutor(max_workers=20,
thread_name_prefix='dns_resolver')
def _fast_getaddrinfo(host, *args, **kwargs):
def needs_dns_resolving(host):
try:
ipaddress.ip_address(host)
return False # already valid IP
except ValueError:
pass # not an IP
if str(host) in ('localhost', 'localhost.',):
return False
return True
def resolve_with_dnspython(host):
addrs = []
expected_errors = (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer,
concurrent.futures.CancelledError, concurrent.futures.TimeoutError)
ipv6_fut = _dns_threads_executor.submit(dns.resolver.query, host, dns.rdatatype.AAAA)
ipv4_fut = _dns_threads_executor.submit(dns.resolver.query, host, dns.rdatatype.A)
# try IPv6
try:
answers = ipv6_fut.result()
addrs += [str(answer) for answer in answers]
except expected_errors as e:
pass
except BaseException as e:
_logger.info(f'dnspython failed to resolve dns (AAAA) for {repr(host)} with error: {repr(e)}')
# try IPv4
try:
answers = ipv4_fut.result()
addrs += [str(answer) for answer in answers]
except expected_errors as e:
# dns failed for some reason, e.g. dns.resolver.NXDOMAIN this is normal.
# Simply report back failure; except if we already have some results.
if not addrs:
raise socket.gaierror(11001, 'getaddrinfo failed') from e
except BaseException as e:
# Possibly internal error in dnspython :( see #4483 and #5638
_logger.info(f'dnspython failed to resolve dns (A) for {repr(host)} with error: {repr(e)}')
if addrs:
return addrs
# Fall back to original socket.getaddrinfo to resolve dns.
return [host]
addrs = [host]
if needs_dns_resolving(host):
addrs = resolve_with_dnspython(host)
list_of_list_of_socketinfos = [socket._getaddrinfo(addr, *args, **kwargs) for addr in addrs]
list_of_socketinfos = [item for lst in list_of_list_of_socketinfos for item in lst]
return list_of_socketinfos

77
electrum/network.py
View File

@ -31,15 +31,12 @@ import threading
import socket
import json
import sys
import ipaddress
import asyncio
from typing import NamedTuple, Optional, Sequence, List, Dict, Tuple, TYPE_CHECKING, Iterable
import traceback
import concurrent
from concurrent import futures
import dns
import dns.resolver
import aiorpcx
from aiorpcx import TaskGroup
from aiohttp import ClientResponse
@ -53,6 +50,7 @@ from .bitcoin import COIN
from . import constants
from . import blockchain
from . import bitcoin
from . import dns_hacks
from .transaction import Transaction
from .blockchain import Blockchain, HEADER_SIZE
from .interface import (Interface, serialize_server, deserialize_server,
@ -228,8 +226,6 @@ class UntrustedServerReturnedError(NetworkException):
return f"<UntrustedServerReturnedError original_exception: {repr(self.original_exception)}>"
_dns_threads_executor = None # type: Optional[concurrent.futures.Executor]
_INSTANCE = None
@ -557,77 +553,10 @@ class Network(Logger):
def _set_proxy(self, proxy: Optional[dict]):
self.proxy = proxy
# Store these somewhere so we can un-monkey-patch
if not hasattr(socket, "_getaddrinfo"):
socket._getaddrinfo = socket.getaddrinfo
if proxy:
self.logger.info(f'setting proxy {proxy}')
# prevent dns leaks, see http://stackoverflow.com/questions/13184205/dns-over-proxy
socket.getaddrinfo = lambda *args: [(socket.AF_INET, socket.SOCK_STREAM, 6, '', (args[0], args[1]))]
else:
if sys.platform == 'win32':
# On Windows, socket.getaddrinfo takes a mutex, and might hold it for up to 10 seconds
# when dns-resolving. To speed it up drastically, we resolve dns ourselves, outside that lock.
# see #4421
resolver = dns.resolver.get_default_resolver()
if resolver.cache is None:
resolver.cache = dns.resolver.Cache()
global _dns_threads_executor
if _dns_threads_executor is None:
_dns_threads_executor = concurrent.futures.ThreadPoolExecutor(max_workers=20)
socket.getaddrinfo = self._fast_getaddrinfo
else:
socket.getaddrinfo = socket._getaddrinfo
dns_hacks.configure_dns_depending_on_proxy(bool(proxy))
self.logger.info(f'setting proxy {proxy}')
self.trigger_callback('proxy_set', self.proxy)
@staticmethod
def _fast_getaddrinfo(host, *args, **kwargs):
def needs_dns_resolving(host):
try:
ipaddress.ip_address(host)
return False # already valid IP
except ValueError:
pass # not an IP
if str(host) in ('localhost', 'localhost.',):
return False
return True
def resolve_with_dnspython(host):
addrs = []
expected_errors = (dns.resolver.NXDOMAIN, dns.resolver.NoAnswer,
concurrent.futures.CancelledError, concurrent.futures.TimeoutError)
ipv6_fut = _dns_threads_executor.submit(dns.resolver.query, host, dns.rdatatype.AAAA)
ipv4_fut = _dns_threads_executor.submit(dns.resolver.query, host, dns.rdatatype.A)
# try IPv6
try:
answers = ipv6_fut.result()
addrs += [str(answer) for answer in answers]
except expected_errors as e:
pass
except BaseException as e:
_logger.info(f'dnspython failed to resolve dns (AAAA) for {repr(host)} with error: {repr(e)}')
# try IPv4
try:
answers = ipv4_fut.result()
addrs += [str(answer) for answer in answers]
except expected_errors as e:
# dns failed for some reason, e.g. dns.resolver.NXDOMAIN this is normal.
# Simply report back failure; except if we already have some results.
if not addrs:
raise socket.gaierror(11001, 'getaddrinfo failed') from e
except BaseException as e:
# Possibly internal error in dnspython :( see #4483 and #5638
_logger.info(f'dnspython failed to resolve dns (A) for {repr(host)} with error: {repr(e)}')
if addrs:
return addrs
# Fall back to original socket.getaddrinfo to resolve dns.
return [host]
addrs = [host]
if needs_dns_resolving(host):
addrs = resolve_with_dnspython(host)
list_of_list_of_socketinfos = [socket._getaddrinfo(addr, *args, **kwargs) for addr in addrs]
list_of_socketinfos = [item for lst in list_of_list_of_socketinfos for item in lst]
return list_of_socketinfos
@log_exceptions
async def set_parameters(self, net_params: NetworkParameters):
proxy = net_params.proxy

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