diff options
Diffstat (limited to 'libmproxy/proxy/layer.py')
-rw-r--r-- | libmproxy/proxy/layer.py | 181 |
1 files changed, 181 insertions, 0 deletions
diff --git a/libmproxy/proxy/layer.py b/libmproxy/proxy/layer.py new file mode 100644 index 00000000..500fb6ba --- /dev/null +++ b/libmproxy/proxy/layer.py @@ -0,0 +1,181 @@ +from __future__ import (absolute_import, print_function, division, unicode_literals) +from libmproxy.protocol.tcp import TCPHandler +from libmproxy.proxy.connection import ServerConnection +from netlib import tcp +from .primitives import Socks5ProxyMode, ProxyError, Log +from .message import Connect, Reconnect, ChangeServer + + +""" +mitmproxy protocol architecture + +In mitmproxy, protocols are implemented as a set of layers, which are composed on top each other. +For example, the following scenarios depict possible scenarios (lowest layer first): + +Transparent HTTP proxy, no SSL: + TransparentModeLayer + HttpLayer + +Regular proxy, CONNECT request with WebSockets over SSL: + RegularModeLayer + HttpLayer + SslLayer + WebsocketLayer (or TcpLayer) + +Automated protocol detection by peeking into the buffer: + TransparentModeLayer + AutoLayer + SslLayer + AutoLayer + Http2Layer + +Communication between layers is done as follows: + - lower layers provide context information to higher layers + - higher layers can "yield" commands to lower layers, + which are propagated until they reach a suitable layer. + +Further goals: + - Connections should always be peekable to make automatic protocol detection work. + - Upstream connections should be established as late as possible; + inline scripts shall have a chance to handle everything locally. +""" + + +class ProxyError2(Exception): + def __init__(self, message, cause=None): + super(ProxyError2, self).__init__(message) + self.cause = cause + + +class RootContext(object): + """ + The outmost context provided to the root layer. + As a consequence, every layer has .client_conn, .channel and .config. + """ + + def __init__(self, client_conn, config, channel): + self.client_conn = client_conn # Client Connection + self.channel = channel # provides .ask() method to communicate with FlowMaster + self.config = config # Proxy Configuration + + def __getattr__(self, name): + """ + Accessing a nonexisting attribute does not throw an error but returns None instead. + """ + return None + + +class LayerCodeCompletion(object): + """ + Dummy class that provides type hinting in PyCharm, which simplifies development a lot. + """ + def __init__(self): + if True: + return + self.config = None + """@type: libmproxy.proxy.config.ProxyConfig""" + self.client_conn = None + """@type: libmproxy.proxy.connection.ClientConnection""" + self.channel = None + """@type: libmproxy.controller.Channel""" + + +class Layer(LayerCodeCompletion): + def __init__(self, ctx): + """ + Args: + ctx: The (read-only) higher layer. + """ + super(Layer, self).__init__() + self.ctx = ctx + + def __call__(self): + """ + Logic of the layer. + Raises: + ProxyError2 in case of protocol exceptions. + """ + raise NotImplementedError + + def __getattr__(self, name): + """ + Attributes not present on the current layer may exist on a higher layer. + """ + return getattr(self.ctx, name) + + def log(self, msg, level, subs=()): + full_msg = [ + "%s:%s: %s" % + (self.client_conn.address.host, + self.client_conn.address.port, + msg)] + for i in subs: + full_msg.append(" -> " + i) + full_msg = "\n".join(full_msg) + self.channel.tell("log", Log(full_msg, level)) + + +class _ServerConnectionMixin(object): + def __init__(self): + self._server_address = None + self.server_conn = None + + def _handle_message(self, message): + if message == Reconnect: + self._disconnect() + self._connect() + return True + elif message == Connect: + self._connect() + return True + elif message == ChangeServer: + raise NotImplementedError + return False + + def _disconnect(self): + """ + Deletes (and closes) an existing server connection. + """ + self.log("serverdisconnect", "debug", [repr(self.server_conn.address)]) + self.server_conn.finish() + self.server_conn.close() + # self.channel.tell("serverdisconnect", self) + self.server_conn = None + + def _connect(self): + self.log("serverconnect", "debug", [repr(self.server_conn.address)]) + try: + self.server_conn.connect() + except tcp.NetLibError as e: + raise ProxyError2("Server connection to '%s' failed: %s" % (self._server_address, repr(e)), e) + + def _set_address(self, address): + a = tcp.Address.wrap(address) + self.log("Set new server address: " + repr(a), "debug") + self.server_conn = ServerConnection(a) + + +class Socks5IncomingLayer(Layer, _ServerConnectionMixin): + def __call__(self): + try: + s5mode = Socks5ProxyMode(self.config.ssl_ports) + address = s5mode.get_upstream_server(self.client_conn)[2:] + except ProxyError as e: + raise ProxyError2(str(e), e) + + self._set_address(address) + + layer = TcpLayer(self) + for message in layer(): + if not self._handle_message(message): + yield message + + +class TcpLayer(Layer): + def __call__(self): + yield Connect() + tcp_handler = TCPHandler(self) + tcp_handler.handle_messages() + + def establish_server_connection(self): + print("establish server conn called")
\ No newline at end of file |