120 lines
3.8 KiB
Python
120 lines
3.8 KiB
Python
# -*- coding: utf-8 -*-
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# Copyright 2014 OpenMarket Ltd
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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from twisted.web.http import HTTPClient
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from twisted.internet import defer, reactor
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from twisted.internet.protocol import ClientFactory
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from twisted.names.srvconnect import SRVConnector
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import json
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import logging
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logger = logging.getLogger(__name__)
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@defer.inlineCallbacks
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def fetch_server_key(server_name, ssl_context_factory):
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"""Fetch the keys for a remote server."""
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factory = SynapseKeyClientFactory()
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SRVConnector(
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reactor, "matrix", server_name, factory,
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protocol="tcp", connectFuncName="connectSSL", defaultPort=443,
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connectFuncKwArgs=dict(contextFactory=ssl_context_factory)).connect()
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server_key, server_certificate = yield factory.remote_key
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defer.returnValue((server_key, server_certificate))
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class SynapseKeyClientError(Exception):
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"""The key wasn't retireved from the remote server."""
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pass
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class SynapseKeyClientProtocol(HTTPClient):
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"""Low level HTTPS client which retrieves an application/json response from
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the server and extracts the X.509 certificate for the remote peer from the
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SSL connection."""
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def connectionMade(self):
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logger.debug("Connected to %s", self.transport.getHost())
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self.sendCommand(b"GET", b"/key")
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self.endHeaders()
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self.timer = reactor.callLater(
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self.factory.timeout_seconds,
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self.on_timeout
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)
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def handleStatus(self, version, status, message):
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if status != b"200":
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logger.info("Non-200 response from %s: %s %s",
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self.transport.getHost(), status, message)
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self.transport.abortConnection()
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def handleResponse(self, response_body_bytes):
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try:
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json_response = json.loads(response_body_bytes)
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except ValueError:
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logger.info("Invalid JSON response from %s",
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self.transport.getHost())
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self.transport.abortConnection()
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return
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certificate = self.transport.getPeerCertificate()
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self.factory.on_remote_key((json_response, certificate))
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self.transport.abortConnection()
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self.timer.cancel()
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def on_timeout(self):
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logger.debug("Timeout waiting for response from %s",
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self.transport.getHost())
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self.transport.abortConnection()
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class SynapseKeyClientFactory(ClientFactory):
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protocol = SynapseKeyClientProtocol
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max_retries = 5
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timeout_seconds = 30
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def __init__(self):
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self.succeeded = False
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self.retries = 0
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self.remote_key = defer.Deferred()
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def on_remote_key(self, key):
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self.succeeded = True
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self.remote_key.callback(key)
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def retry_connection(self, connector):
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self.retries += 1
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if self.retries < self.max_retries:
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connector.connector = None
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connector.connect()
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else:
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self.remote_key.errback(
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SynapseKeyClientError("Max retries exceeded"))
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def clientConnectionFailed(self, connector, reason):
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logger.info("Connection failed %s", reason)
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self.retry_connection(connector)
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def clientConnectionLost(self, connector, reason):
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logger.info("Connection lost %s", reason)
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if not self.succeeded:
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self.retry_connection(connector)
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