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Diffstat (limited to 'mitmproxy/libmproxy/protocol/base.py')
| -rw-r--r-- | mitmproxy/libmproxy/protocol/base.py | 198 |
1 files changed, 198 insertions, 0 deletions
diff --git a/mitmproxy/libmproxy/protocol/base.py b/mitmproxy/libmproxy/protocol/base.py new file mode 100644 index 00000000..40fcaf65 --- /dev/null +++ b/mitmproxy/libmproxy/protocol/base.py @@ -0,0 +1,198 @@ +from __future__ import (absolute_import, print_function, division) +import sys + +import six + +from ..models import ServerConnection +from ..exceptions import ProtocolException +from netlib.exceptions import TcpException + + +class _LayerCodeCompletion(object): + + """ + Dummy class that provides type hinting in PyCharm, which simplifies development a lot. + """ + + def __init__(self, **mixin_args): # pragma: no cover + super(_LayerCodeCompletion, self).__init__(**mixin_args) + if True: + return + self.config = None + """@type: libmproxy.proxy.ProxyConfig""" + self.client_conn = None + """@type: libmproxy.models.ClientConnection""" + self.server_conn = None + """@type: libmproxy.models.ServerConnection""" + self.channel = None + """@type: libmproxy.controller.Channel""" + self.ctx = None + """@type: libmproxy.protocol.Layer""" + + +class Layer(_LayerCodeCompletion): + + """ + Base class for all layers. All other protocol layers should inherit from this class. + """ + + def __init__(self, ctx, **mixin_args): + """ + Each layer usually passes itself to its child layers as a context. Properties of the + context are transparently mapped to the layer, so that the following works: + + .. code-block:: python + + root_layer = Layer(None) + root_layer.client_conn = 42 + sub_layer = Layer(root_layer) + print(sub_layer.client_conn) # 42 + + The root layer is passed a :py:class:`libmproxy.proxy.RootContext` object, + which provides access to :py:attr:`.client_conn <libmproxy.proxy.RootContext.client_conn>`, + :py:attr:`.next_layer <libmproxy.proxy.RootContext.next_layer>` and other basic attributes. + + Args: + ctx: The (read-only) parent layer / context. + """ + self.ctx = ctx + """ + The parent layer. + + :type: :py:class:`Layer` + """ + super(Layer, self).__init__(**mixin_args) + + def __call__(self): + """Logic of the layer. + + Returns: + Once the protocol has finished without exceptions. + + Raises: + ~libmproxy.exceptions.ProtocolException: if an exception occurs. No other exceptions must be raised. + """ + raise NotImplementedError() + + def __getattr__(self, name): + """ + Attributes not present on the current layer are looked up on the context. + """ + return getattr(self.ctx, name) + + @property + def layers(self): + """ + List of all layers, including the current layer (``[self, self.ctx, self.ctx.ctx, ...]``) + """ + return [self] + self.ctx.layers + + def __repr__(self): + return type(self).__name__ + + +class ServerConnectionMixin(object): + + """ + Mixin that provides a layer with the capabilities to manage a server connection. + The server address can be passed in the constructor or set by calling :py:meth:`set_server`. + Subclasses are responsible for calling :py:meth:`disconnect` before returning. + + Recommended Usage: + + .. code-block:: python + + class MyLayer(Layer, ServerConnectionMixin): + def __call__(self): + try: + # Do something. + finally: + if self.server_conn: + self.disconnect() + """ + + def __init__(self, server_address=None): + super(ServerConnectionMixin, self).__init__() + self.server_conn = ServerConnection(server_address, (self.config.host, 0)) + self.__check_self_connect() + + def __check_self_connect(self): + """ + We try to protect the proxy from _accidentally_ connecting to itself, + e.g. because of a failed transparent lookup or an invalid configuration. + """ + address = self.server_conn.address + if address: + self_connect = ( + address.port == self.config.port and + address.host in ("localhost", "127.0.0.1", "::1") + ) + if self_connect: + raise ProtocolException( + "Invalid server address: {}\r\n" + "The proxy shall not connect to itself.".format(repr(address)) + ) + + def set_server(self, address, server_tls=None, sni=None): + """ + Sets a new server address. If there is an existing connection, it will be closed. + + Raises: + ~libmproxy.exceptions.ProtocolException: + if ``server_tls`` is ``True``, but there was no TLS layer on the + protocol stack which could have processed this. + """ + if self.server_conn: + self.disconnect() + self.log("Set new server address: " + repr(address), "debug") + self.server_conn.address = address + self.__check_self_connect() + if server_tls: + raise ProtocolException( + "Cannot upgrade to TLS, no TLS layer on the protocol stack." + ) + + def disconnect(self): + """ + Deletes (and closes) an existing server connection. + Must not be called if there is no existing connection. + """ + self.log("serverdisconnect", "debug", [repr(self.server_conn.address)]) + address = self.server_conn.address + source_address = self.server_conn.source_address + self.server_conn.finish() + self.server_conn.close() + self.channel.tell("serverdisconnect", self.server_conn) + self.server_conn = ServerConnection(address, source_address) + + def connect(self): + """ + Establishes a server connection. + Must not be called if there is an existing connection. + + Raises: + ~libmproxy.exceptions.ProtocolException: if the connection could not be established. + """ + if not self.server_conn.address: + raise ProtocolException("Cannot connect to server, no server address given.") + self.log("serverconnect", "debug", [repr(self.server_conn.address)]) + self.channel.ask("serverconnect", self.server_conn) + try: + self.server_conn.connect() + except TcpException as e: + six.reraise( + ProtocolException, + ProtocolException( + "Server connection to {} failed: {}".format( + repr(self.server_conn.address), str(e) + ) + ), + sys.exc_info()[2] + ) + + +class Kill(Exception): + + """ + Signal that both client and server connection(s) should be killed immediately. + """ |