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Diffstat (limited to '')
| -rw-r--r-- | synapse/http/connectproxyclient.py | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/synapse/http/connectproxyclient.py b/synapse/http/connectproxyclient.py new file mode 100644 index 0000000000..be7b2ceb8e --- /dev/null +++ b/synapse/http/connectproxyclient.py @@ -0,0 +1,195 @@ +# -*- 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 |