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#!/usr/bin/env python
#
# Electrum - lightweight Bitcoin client
# Copyright (C) 2011 thomasv@gitorious
#
# Permission is hereby granted, free of charge, to any person
# obtaining a copy of this software and associated documentation files
# (the "Software"), to deal in the Software without restriction,
# including without limitation the rights to use, copy, modify, merge,
# publish, distribute, sublicense, and/or sell copies of the Software,
# and to permit persons to whom the Software is furnished to do so,
# subject to the following conditions:
#
# The above copyright notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
# BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
import os
import re
import ssl
import sys
import traceback
import asyncio
import socket
from typing import Tuple, Union, List, TYPE_CHECKING, Optional
from collections import defaultdict
from ipaddress import IPv4Network, IPv6Network, ip_address
import itertools
import logging
import aiorpcx
from aiorpcx import RPCSession, Notification, NetAddress
from aiorpcx.curio import timeout_after, TaskTimeout
from aiorpcx.jsonrpc import JSONRPC, CodeMessageError
from aiorpcx.rawsocket import RSClient
import certifi
from .util import ignore_exceptions, log_exceptions, bfh, SilentTaskGroup
from . import util
from . import x509
from . import pem
from . import version
from . import blockchain
from .blockchain import Blockchain
from . import constants
from .i18n import _
from .logging import Logger
if TYPE_CHECKING:
from .network import Network
ca_path = certifi.where()
BUCKET_NAME_OF_ONION_SERVERS = 'onion'
class NetworkTimeout:
# seconds
class Generic:
NORMAL = 30
RELAXED = 45
MOST_RELAXED = 180
class Urgent(Generic):
NORMAL = 10
RELAXED = 20
MOST_RELAXED = 60
class NotificationSession(RPCSession):
def __init__(self, *args, **kwargs):
super(NotificationSession, self).__init__(*args, **kwargs)
self.subscriptions = defaultdict(list)
self.cache = {}
self.default_timeout = NetworkTimeout.Generic.NORMAL
self._msg_counter = itertools.count(start=1)
self.interface = None # type: Optional[Interface]
self.cost_hard_limit = 0 # disable aiorpcx resource limits
async def handle_request(self, request):
self.maybe_log(f"--> {request}")
try:
if isinstance(request, Notification):
params, result = request.args[:-1], request.args[-1]
key = self.get_hashable_key_for_rpc_call(request.method, params)
if key in self.subscriptions:
self.cache[key] = result
for queue in self.subscriptions[key]:
await queue.put(request.args)
else:
raise Exception(f'unexpected notification')
else:
raise Exception(f'unexpected request. not a notification')
except Exception as e:
self.interface.logger.info(f"error handling request {request}. exc: {repr(e)}")
await self.close()
async def send_request(self, *args, timeout=None, **kwargs):
# note: semaphores/timeouts/backpressure etc are handled by
# aiorpcx. the timeout arg here in most cases should not be set
msg_id = next(self._msg_counter)
self.maybe_log(f"<-- {args} {kwargs} (id: {msg_id})")
try:
# note: RPCSession.send_request raises TaskTimeout in case of a timeout.
# TaskTimeout is a subclass of CancelledError, which is *suppressed* in TaskGroups
response = await asyncio.wait_for(
super().send_request(*args, **kwargs),
timeout)
except (TaskTimeout, asyncio.TimeoutError) as e:
raise RequestTimedOut(f'request timed out: {args} (id: {msg_id})') from e
except CodeMessageError as e:
self.maybe_log(f"--> {repr(e)} (id: {msg_id})")
raise
else:
self.maybe_log(f"--> {response} (id: {msg_id})")
return response
def set_default_timeout(self, timeout):
self.sent_request_timeout = timeout
self.max_send_delay = timeout
async def subscribe(self, method: str, params: List, queue: asyncio.Queue):
# note: until the cache is written for the first time,
# each 'subscribe' call might make a request on the network.
key = self.get_hashable_key_for_rpc_call(method, params)
self.subscriptions[key].append(queue)
if key in self.cache:
result = self.cache[key]
else:
result = await self.send_request(method, params)
self.cache[key] = result
await queue.put(params + [result])
def unsubscribe(self, queue):
"""Unsubscribe a callback to free object references to enable GC."""
# note: we can't unsubscribe from the server, so we keep receiving
# subsequent notifications
for v in self.subscriptions.values():
if queue in v:
v.remove(queue)
@classmethod
def get_hashable_key_for_rpc_call(cls, method, params):
"""Hashable index for subscriptions and cache"""
return str(method) + repr(params)
def maybe_log(self, msg: str) -> None:
if not self.interface: return
if self.interface.debug or self.interface.network.debug:
self.interface.logger.debug(msg)
class NetworkException(Exception): pass
class GracefulDisconnect(NetworkException):
log_level = logging.INFO
def __init__(self, *args, log_level=None, **kwargs):
Exception.__init__(self, *args, **kwargs)
if log_level is not None:
self.log_level = log_level
class RequestTimedOut(GracefulDisconnect):
def __str__(self):
return _("Network request timed out.")
class ErrorParsingSSLCert(Exception): pass
class ErrorGettingSSLCertFromServer(Exception): pass
class ConnectError(NetworkException): pass
class _RSClient(RSClient):
async def create_connection(self):
try:
return await super().create_connection()
except OSError as e:
# note: using "from e" here will set __cause__ of ConnectError
raise ConnectError(e) from e
def deserialize_server(server_str: str) -> Tuple[str, str, str]:
# host might be IPv6 address, hence do rsplit:
host, port, protocol = str(server_str).rsplit(':', 2)
if not host:
raise ValueError('host must not be empty')
if protocol not in ('s', 't'):
raise ValueError('invalid network protocol: {}'.format(protocol))
int(port) # Throw if cannot be converted to int
if not (0 < int(port) < 2**16):
raise ValueError('port {} is out of valid range'.format(port))
return host, port, protocol
def serialize_server(host: str, port: Union[str, int], protocol: str) -> str:
return str(':'.join([host, str(port), protocol]))
class Interface(Logger):
LOGGING_SHORTCUT = 'i'
def __init__(self, network: 'Network', server: str, proxy: Optional[dict]):
self.ready = asyncio.Future()
self.got_disconnected = asyncio.Future()
self.server = server
self.host, self.port, self.protocol = deserialize_server(self.server)
self.port = int(self.port)
Logger.__init__(self)
assert network.config.path
self.cert_path = os.path.join(network.config.path, 'certs', self.host)
self.blockchain = None
self._requested_chunks = set()
self.network = network
self._set_proxy(proxy)
self.session = None # type: NotificationSession
self._ipaddr_bucket = None
self.tip_header = None
self.tip = 0
# Dump network messages (only for this interface). Set at runtime from the console.
self.debug = False
asyncio.run_coroutine_threadsafe(
self.network.main_taskgroup.spawn(self.run()), self.network.asyncio_loop)
self.group = SilentTaskGroup()
def diagnostic_name(self):
return f"{self.host}:{self.port}"
def _set_proxy(self, proxy: dict):
if proxy:
username, pw = proxy.get('user'), proxy.get('password')
if not username or not pw:
auth = None
else:
auth = aiorpcx.socks.SOCKSUserAuth(username, pw)
addr = NetAddress(proxy['host'], proxy['port'])
if proxy['mode'] == "socks4":
self.proxy = aiorpcx.socks.SOCKSProxy(addr, aiorpcx.socks.SOCKS4a, auth)
elif proxy['mode'] == "socks5":
self.proxy = aiorpcx.socks.SOCKSProxy(addr, aiorpcx.socks.SOCKS5, auth)
else:
raise NotImplementedError # http proxy not available with aiorpcx
else:
self.proxy = None
async def is_server_ca_signed(self, ca_ssl_context):
"""Given a CA enforcing SSL context, returns True if the connection
can be established. Returns False if the server has a self-signed
certificate but otherwise is okay. Any other failures raise.
"""
try:
await self.open_session(ca_ssl_context, exit_early=True)
except ConnectError as e:
cause = e.__cause__
if isinstance(cause, ssl.SSLError) and cause.reason == 'CERTIFICATE_VERIFY_FAILED':
# failures due to self-signed certs are normal
return False
raise
return True
async def _try_saving_ssl_cert_for_first_time(self, ca_ssl_context):
ca_signed = await self.is_server_ca_signed(ca_ssl_context)
if ca_signed:
with open(self.cert_path, 'w') as f:
# empty file means this is CA signed, not self-signed
f.write('')
else:
await self.save_certificate()
def _is_saved_ssl_cert_available(self):
if not os.path.exists(self.cert_path):
return False
with open(self.cert_path, 'r') as f:
contents = f.read()
if contents == '': # CA signed
return True
# pinned self-signed cert
try:
b = pem.dePem(contents, 'CERTIFICATE')
except SyntaxError as e:
self.logger.info(f"error parsing already saved cert: {e}")
raise ErrorParsingSSLCert(e) from e
try:
x = x509.X509(b)
except Exception as e:
self.logger.info(f"error parsing already saved cert: {e}")
raise ErrorParsingSSLCert(e) from e
try:
x.check_date()
return True
except x509.CertificateError as e:
self.logger.info(f"certificate has expired: {e}")
os.unlink(self.cert_path) # delete pinned cert only in this case
return False
async def _get_ssl_context(self):
if self.protocol != 's':
# using plaintext TCP
return None
# see if we already have cert for this server; or get it for the first time
ca_sslc = ssl.create_default_context(purpose=ssl.Purpose.SERVER_AUTH, cafile=ca_path)
if not self._is_saved_ssl_cert_available():
try:
await self._try_saving_ssl_cert_for_first_time(ca_sslc)
except (OSError, ConnectError, aiorpcx.socks.SOCKSError) as e:
raise ErrorGettingSSLCertFromServer(e) from e
# now we have a file saved in our certificate store
siz = os.stat(self.cert_path).st_size
if siz == 0:
# CA signed cert
sslc = ca_sslc
else:
# pinned self-signed cert
sslc = ssl.create_default_context(ssl.Purpose.SERVER_AUTH, cafile=self.cert_path)
sslc.check_hostname = 0
return sslc
def handle_disconnect(func):
async def wrapper_func(self: 'Interface', *args, **kwargs):
try:
return await func(self, *args, **kwargs)
except GracefulDisconnect as e:
self.logger.log(e.log_level, f"disconnecting due to {repr(e)}")
except aiorpcx.jsonrpc.RPCError as e:
self.logger.warning(f"disconnecting due to {repr(e)}")
self.logger.debug(f"(disconnect) trace for {repr(e)}", exc_info=True)
finally:
await self.network.connection_down(self)
if not self.got_disconnected.done():
self.got_disconnected.set_result(1)
# if was not 'ready' yet, schedule waiting coroutines:
self.ready.cancel()
return wrapper_func
@ignore_exceptions # do not kill main_taskgroup
@log_exceptions
@handle_disconnect
async def run(self):
try:
ssl_context = await self._get_ssl_context()
except (ErrorParsingSSLCert, ErrorGettingSSLCertFromServer) as e:
self.logger.info(f'disconnecting due to: {repr(e)}')
return
try:
await self.open_session(ssl_context)
except (asyncio.CancelledError, ConnectError, aiorpcx.socks.SOCKSError) as e:
self.logger.info(f'disconnecting due to: {repr(e)}')
return
def mark_ready(self):
if self.ready.cancelled():
raise GracefulDisconnect('conn establishment was too slow; *ready* future was cancelled')
if self.ready.done():
return
assert self.tip_header
chain = blockchain.check_header(self.tip_header)
if not chain:
self.blockchain = blockchain.get_best_chain()
else:
self.blockchain = chain
assert self.blockchain is not None
self.logger.info(f"set blockchain with height {self.blockchain.height()}")
self.ready.set_result(1)
async def save_certificate(self):
if not os.path.exists(self.cert_path):
# we may need to retry this a few times, in case the handshake hasn't completed
for _ in range(10):
dercert = await self.get_certificate()
if dercert:
self.logger.info("succeeded in getting cert")
with open(self.cert_path, 'w') as f:
cert = ssl.DER_cert_to_PEM_cert(dercert)
# workaround android bug
cert = re.sub("([^\n])-----END CERTIFICATE-----","\\1\n-----END CERTIFICATE-----",cert)
f.write(cert)
# even though close flushes we can't fsync when closed.
# and we must flush before fsyncing, cause flush flushes to OS buffer
# fsync writes to OS buffer to disk
f.flush()
os.fsync(f.fileno())
break
await asyncio.sleep(1)
else:
raise GracefulDisconnect("could not get certificate after 10 tries")
async def get_certificate(self):
sslc = ssl.SSLContext()
try:
async with _RSClient(session_factory=RPCSession,
host=self.host, port=self.port,
ssl=sslc, proxy=self.proxy) as session:
return session.transport._asyncio_transport._ssl_protocol._sslpipe._sslobj.getpeercert(True)
except ValueError:
return None
async def get_block_header(self, height, assert_mode):
self.logger.info(f'requesting block header {height} in mode {assert_mode}')
# use lower timeout as we usually have network.bhi_lock here
timeout = self.network.get_network_timeout_seconds(NetworkTimeout.Urgent)
res = await self.session.send_request('blockchain.block.header', [height], timeout=timeout)
return blockchain.deserialize_header(bytes.fromhex(res), height)
async def request_chunk(self, height, tip=None, *, can_return_early=False):
index = height // 2016
if can_return_early and index in self._requested_chunks:
return
self.logger.info(f"requesting chunk from height {height}")
size = 2016
if tip is not None:
size = min(size, tip - index * 2016 + 1)
size = max(size, 0)
try:
self._requested_chunks.add(index)
res = await self.session.send_request('blockchain.block.headers', [index * 2016, size])
finally:
try: self._requested_chunks.remove(index)
except KeyError: pass
conn = self.blockchain.connect_chunk(index, res['hex'])
if not conn:
return conn, 0
return conn, res['count']
def is_main_server(self) -> bool:
return self.network.default_server == self.server
async def open_session(self, sslc, exit_early=False):
async with _RSClient(session_factory=NotificationSession,
host=self.host, port=self.port,
ssl=sslc, proxy=self.proxy) as session:
self.session = session # type: NotificationSession
self.session.interface = self
self.session.set_default_timeout(self.network.get_network_timeout_seconds(NetworkTimeout.Generic))
try:
ver = await session.send_request('server.version', [self.client_name(), version.PROTOCOL_VERSION])
except aiorpcx.jsonrpc.RPCError as e:
raise GracefulDisconnect(e) # probably 'unsupported protocol version'
if exit_early:
return
if not self.network.check_interface_against_healthy_spread_of_connected_servers(self):
raise GracefulDisconnect(f'too many connected servers already '
f'in bucket {self.bucket_based_on_ipaddress()}')
self.logger.info(f"connection established. version: {ver}")
try:
async with self.group as group:
await group.spawn(self.ping)
await group.spawn(self.run_fetch_blocks)
await group.spawn(self.monitor_connection)
except aiorpcx.jsonrpc.RPCError as e:
if e.code in (JSONRPC.EXCESSIVE_RESOURCE_USAGE,
JSONRPC.SERVER_BUSY,
JSONRPC.METHOD_NOT_FOUND):
raise GracefulDisconnect(e, log_level=logging.WARNING) from e
raise
async def monitor_connection(self):
while True:
await asyncio.sleep(1)
if not self.session or self.session.is_closing():
raise GracefulDisconnect('session was closed')
async def ping(self):
while True:
await asyncio.sleep(300)
await self.session.send_request('server.ping')
async def close(self):
if self.session:
await self.session.close()
# monitor_connection will cancel tasks
async def run_fetch_blocks(self):
header_queue = asyncio.Queue()
await self.session.subscribe('blockchain.headers.subscribe', [], header_queue)
while True:
item = await header_queue.get()
raw_header = item[0]
height = raw_header['height']
header = blockchain.deserialize_header(bfh(raw_header['hex']), height)
self.tip_header = header
self.tip = height
if self.tip < constants.net.max_checkpoint():
raise GracefulDisconnect('server tip below max checkpoint')
self.mark_ready()
await self._process_header_at_tip()
self.network.trigger_callback('network_updated')
await self.network.switch_unwanted_fork_interface()
await self.network.switch_lagging_interface()
async def _process_header_at_tip(self):
height, header = self.tip, self.tip_header
async with self.network.bhi_lock:
if self.blockchain.height() >= height and self.blockchain.check_header(header):
# another interface amended the blockchain
self.logger.info(f"skipping header {height}")
return
_, height = await self.step(height, header)
# in the simple case, height == self.tip+1
if height <= self.tip:
await self.sync_until(height)
self.network.trigger_callback('blockchain_updated')
async def sync_until(self, height, next_height=None):
if next_height is None:
next_height = self.tip
last = None
while last is None or height <= next_height:
prev_last, prev_height = last, height
if next_height > height + 10:
could_connect, num_headers = await self.request_chunk(height, next_height)
if not could_connect:
if height <= constants.net.max_checkpoint():
raise GracefulDisconnect('server chain conflicts with checkpoints or genesis')
last, height = await self.step(height)
continue
self.network.trigger_callback('network_updated')
height = (height // 2016 * 2016) + num_headers
assert height <= next_height+1, (height, self.tip)
last = 'catchup'
else:
last, height = await self.step(height)
assert (prev_last, prev_height) != (last, height), 'had to prevent infinite loop in interface.sync_until'
return last, height
async def step(self, height, header=None):
assert 0 <= height <= self.tip, (height, self.tip)
if header is None:
header = await self.get_block_header(height, 'catchup')
chain = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
if chain:
self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
# note: there is an edge case here that is not handled.
# we might know the blockhash (enough for check_header) but
# not have the header itself. e.g. regtest chain with only genesis.
# this situation resolves itself on the next block
return 'catchup', height+1
can_connect = blockchain.can_connect(header) if 'mock' not in header else header['mock']['connect'](height)
if not can_connect:
self.logger.info(f"can't connect {height}")
height, header, bad, bad_header = await self._search_headers_backwards(height, header)
chain = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
can_connect = blockchain.can_connect(header) if 'mock' not in header else header['mock']['connect'](height)
assert chain or can_connect
if can_connect:
self.logger.info(f"could connect {height}")
height += 1
if isinstance(can_connect, Blockchain): # not when mocking
self.blockchain = can_connect
self.blockchain.save_header(header)
return 'catchup', height
good, bad, bad_header = await self._search_headers_binary(height, bad, bad_header, chain)
return await self._resolve_potential_chain_fork_given_forkpoint(good, bad, bad_header)
async def _search_headers_binary(self, height, bad, bad_header, chain):
assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
good = height
while True:
assert good < bad, (good, bad)
height = (good + bad) // 2
self.logger.info(f"binary step. good {good}, bad {bad}, height {height}")
header = await self.get_block_header(height, 'binary')
chain = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
if chain:
self.blockchain = chain if isinstance(chain, Blockchain) else self.blockchain
good = height
else:
bad = height
bad_header = header
if good + 1 == bad:
break
mock = 'mock' in bad_header and bad_header['mock']['connect'](height)
real = not mock and self.blockchain.can_connect(bad_header, check_height=False)
if not real and not mock:
raise Exception('unexpected bad header during binary: {}'.format(bad_header))
_assert_header_does_not_check_against_any_chain(bad_header)
self.logger.info(f"binary search exited. good {good}, bad {bad}")
return good, bad, bad_header
async def _resolve_potential_chain_fork_given_forkpoint(self, good, bad, bad_header):
assert good + 1 == bad
assert bad == bad_header['block_height']
_assert_header_does_not_check_against_any_chain(bad_header)
# 'good' is the height of a block 'good_header', somewhere in self.blockchain.
# bad_header connects to good_header; bad_header itself is NOT in self.blockchain.
bh = self.blockchain.height()
assert bh >= good, (bh, good)
if bh == good:
height = good + 1
self.logger.info(f"catching up from {height}")
return 'no_fork', height
# this is a new fork we don't yet have
height = bad + 1
self.logger.info(f"new fork at bad height {bad}")
forkfun = self.blockchain.fork if 'mock' not in bad_header else bad_header['mock']['fork']
b = forkfun(bad_header) # type: Blockchain
self.blockchain = b
assert b.forkpoint == bad
return 'fork', height
async def _search_headers_backwards(self, height, header):
async def iterate():
nonlocal height, header
checkp = False
if height <= constants.net.max_checkpoint():
height = constants.net.max_checkpoint()
checkp = True
header = await self.get_block_header(height, 'backward')
chain = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
can_connect = blockchain.can_connect(header) if 'mock' not in header else header['mock']['connect'](height)
if chain or can_connect:
return False
if checkp:
raise GracefulDisconnect("server chain conflicts with checkpoints")
return True
bad, bad_header = height, header
_assert_header_does_not_check_against_any_chain(bad_header)
with blockchain.blockchains_lock: chains = list(blockchain.blockchains.values())
local_max = max([0] + [x.height() for x in chains]) if 'mock' not in header else float('inf')
height = min(local_max + 1, height - 1)
while await iterate():
bad, bad_header = height, header
delta = self.tip - height
height = self.tip - 2 * delta
_assert_header_does_not_check_against_any_chain(bad_header)
self.logger.info(f"exiting backward mode at {height}")
return height, header, bad, bad_header
@classmethod
def client_name(cls) -> str:
return f'electrum/{version.ELECTRUM_VERSION}'
def is_tor(self):
return self.host.endswith('.onion')
def ip_addr(self) -> Optional[str]:
session = self.session
if not session: return None
peer_addr = session.remote_address()
if not peer_addr: return None
return str(peer_addr.host)
def bucket_based_on_ipaddress(self) -> str:
def do_bucket():
if self.is_tor():
return BUCKET_NAME_OF_ONION_SERVERS
try:
ip_addr = ip_address(self.ip_addr())
except ValueError:
return ''
if not ip_addr:
return ''
if ip_addr.version == 4:
slash16 = IPv4Network(ip_addr).supernet(prefixlen_diff=32-16)
return str(slash16)
elif ip_addr.version == 6:
slash48 = IPv6Network(ip_addr).supernet(prefixlen_diff=128-48)
return str(slash48)
return ''
if not self._ipaddr_bucket:
self._ipaddr_bucket = do_bucket()
return self._ipaddr_bucket
def _assert_header_does_not_check_against_any_chain(header: dict) -> None:
chain_bad = blockchain.check_header(header) if 'mock' not in header else header['mock']['check'](header)
if chain_bad:
raise Exception('bad_header must not check!')
def check_cert(host, cert):
try:
b = pem.dePem(cert, 'CERTIFICATE')
x = x509.X509(b)
except:
traceback.print_exc(file=sys.stdout)
return
try:
x.check_date()
expired = False
except:
expired = True
m = "host: %s\n"%host
m += "has_expired: %s\n"% expired
util.print_msg(m)
# Used by tests
def _match_hostname(name, val):
if val == name:
return True
return val.startswith('*.') and name.endswith(val[1:])
def test_certificates():
from .simple_config import SimpleConfig
config = SimpleConfig()
mydir = os.path.join(config.path, "certs")
certs = os.listdir(mydir)
for c in certs:
p = os.path.join(mydir,c)
with open(p, encoding='utf-8') as f:
cert = f.read()
check_cert(c, cert)
if __name__ == "__main__":
test_certificates()