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- # -*- coding: utf-8 -*-
- # Copyright 2019 The Matrix.org Foundation C.I.C.
- #
- # Licensed under the Apache License, Version 2.0 (the "License");
- # you may not use this file except in compliance with the License.
- # You may obtain a copy of the License at
- #
- # http://www.apache.org/licenses/LICENSE-2.0
- #
- # Unless required by applicable law or agreed to in writing, software
- # distributed under the License is distributed on an "AS IS" BASIS,
- # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- # See the License for the specific language governing permissions and
- # limitations under the License.
- import logging
- from zope.interface import implementer
- from twisted.internet import defer, protocol
- from twisted.internet.error import ConnectError
- from twisted.internet.interfaces import IStreamClientEndpoint
- from twisted.internet.protocol import connectionDone
- from twisted.web import http
- logger = logging.getLogger(__name__)
- class ProxyConnectError(ConnectError):
- pass
- @implementer(IStreamClientEndpoint)
- class HTTPConnectProxyEndpoint(object):
- """An Endpoint implementation which will send a CONNECT request to an http proxy
- Wraps an existing HostnameEndpoint for the proxy.
- When we get the connect() request from the connection pool (via the TLS wrapper),
- we'll first connect to the proxy endpoint with a ProtocolFactory which will make the
- CONNECT request. Once that completes, we invoke the protocolFactory which was passed
- in.
- Args:
- reactor: the Twisted reactor to use for the connection
- proxy_endpoint (IStreamClientEndpoint): the endpoint to use to connect to the
- proxy
- host (bytes): hostname that we want to CONNECT to
- port (int): port that we want to connect to
- """
- def __init__(self, reactor, proxy_endpoint, host, port):
- self._reactor = reactor
- self._proxy_endpoint = proxy_endpoint
- self._host = host
- self._port = port
- def __repr__(self):
- return "<HTTPConnectProxyEndpoint %s>" % (self._proxy_endpoint,)
- def connect(self, protocolFactory):
- f = HTTPProxiedClientFactory(self._host, self._port, protocolFactory)
- d = self._proxy_endpoint.connect(f)
- # once the tcp socket connects successfully, we need to wait for the
- # CONNECT to complete.
- d.addCallback(lambda conn: f.on_connection)
- return d
- class HTTPProxiedClientFactory(protocol.ClientFactory):
- """ClientFactory wrapper that triggers an HTTP proxy CONNECT on connect.
- Once the CONNECT completes, invokes the original ClientFactory to build the
- HTTP Protocol object and run the rest of the connection.
- Args:
- dst_host (bytes): hostname that we want to CONNECT to
- dst_port (int): port that we want to connect to
- wrapped_factory (protocol.ClientFactory): The original Factory
- """
- def __init__(self, dst_host, dst_port, wrapped_factory):
- self.dst_host = dst_host
- self.dst_port = dst_port
- self.wrapped_factory = wrapped_factory
- self.on_connection = defer.Deferred()
- def startedConnecting(self, connector):
- return self.wrapped_factory.startedConnecting(connector)
- def buildProtocol(self, addr):
- wrapped_protocol = self.wrapped_factory.buildProtocol(addr)
- return HTTPConnectProtocol(
- self.dst_host, self.dst_port, wrapped_protocol, self.on_connection
- )
- def clientConnectionFailed(self, connector, reason):
- logger.debug("Connection to proxy failed: %s", reason)
- if not self.on_connection.called:
- self.on_connection.errback(reason)
- return self.wrapped_factory.clientConnectionFailed(connector, reason)
- def clientConnectionLost(self, connector, reason):
- logger.debug("Connection to proxy lost: %s", reason)
- if not self.on_connection.called:
- self.on_connection.errback(reason)
- return self.wrapped_factory.clientConnectionLost(connector, reason)
- class HTTPConnectProtocol(protocol.Protocol):
- """Protocol that wraps an existing Protocol to do a CONNECT handshake at connect
- Args:
- host (bytes): The original HTTP(s) hostname or IPv4 or IPv6 address literal
- to put in the CONNECT request
- port (int): The original HTTP(s) port to put in the CONNECT request
- wrapped_protocol (interfaces.IProtocol): the original protocol (probably
- HTTPChannel or TLSMemoryBIOProtocol, but could be anything really)
- connected_deferred (Deferred): a Deferred which will be callbacked with
- wrapped_protocol when the CONNECT completes
- """
- def __init__(self, host, port, wrapped_protocol, connected_deferred):
- self.host = host
- self.port = port
- self.wrapped_protocol = wrapped_protocol
- self.connected_deferred = connected_deferred
- self.http_setup_client = HTTPConnectSetupClient(self.host, self.port)
- self.http_setup_client.on_connected.addCallback(self.proxyConnected)
- def connectionMade(self):
- self.http_setup_client.makeConnection(self.transport)
- def connectionLost(self, reason=connectionDone):
- if self.wrapped_protocol.connected:
- self.wrapped_protocol.connectionLost(reason)
- self.http_setup_client.connectionLost(reason)
- if not self.connected_deferred.called:
- self.connected_deferred.errback(reason)
- def proxyConnected(self, _):
- self.wrapped_protocol.makeConnection(self.transport)
- self.connected_deferred.callback(self.wrapped_protocol)
- # Get any pending data from the http buf and forward it to the original protocol
- buf = self.http_setup_client.clearLineBuffer()
- if buf:
- self.wrapped_protocol.dataReceived(buf)
- def dataReceived(self, data):
- # if we've set up the HTTP protocol, we can send the data there
- if self.wrapped_protocol.connected:
- return self.wrapped_protocol.dataReceived(data)
- # otherwise, we must still be setting up the connection: send the data to the
- # setup client
- return self.http_setup_client.dataReceived(data)
- class HTTPConnectSetupClient(http.HTTPClient):
- """HTTPClient protocol to send a CONNECT message for proxies and read the response.
- Args:
- host (bytes): The hostname to send in the CONNECT message
- port (int): The port to send in the CONNECT message
- """
- def __init__(self, host, port):
- self.host = host
- self.port = port
- self.on_connected = defer.Deferred()
- def connectionMade(self):
- logger.debug("Connected to proxy, sending CONNECT")
- self.sendCommand(b"CONNECT", b"%s:%d" % (self.host, self.port))
- self.endHeaders()
- def handleStatus(self, version, status, message):
- logger.debug("Got Status: %s %s %s", status, message, version)
- if status != b"200":
- raise ProxyConnectError("Unexpected status on CONNECT: %s" % status)
- def handleEndHeaders(self):
- logger.debug("End Headers")
- self.on_connected.callback(None)
- def handleResponse(self, body):
- pass
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