first initial proof-of-concept

3 files changed, 282 insertions, 8 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
diff --git a/libmproxy/proxy/message.py b/libmproxy/proxy/message.py
new file mode 100644
index 00000000..a667123c
--- /dev/null
+++ b/libmproxy/proxy/message.py
@@ -0,0 +1,40 @@
+"""
+This module contains all valid messages layers can send to the underlying layers.
+"""
+
+
+class _Message(object):
+    def __eq__(self, other):
+        # Allow message == Connect checks.
+        # FIXME: make Connect == message work.
+        if isinstance(self, other):
+            return True
+        return self is other
+
+
+class Connect(_Message):
+    """
+    Connect to the server
+    """
+
+
+class Reconnect(_Message):
+    """
+    Re-establish the server connection
+    """
+
+
+class ChangeServer(_Message):
+    """
+    Change the upstream server.
+    """
+
+    def __init__(self, address, server_ssl, sni, depth=1):
+        self.address = address
+        self.server_ssl = server_ssl
+        self.sni = sni
+
+        # upstream proxy scenario: you may want to change either the final target or the upstream proxy.
+        # We can express this neatly as the "nth-server-providing-layer"
+        # ServerConnection could get a `via` attribute.
+        self.depth = depth
diff --git a/libmproxy/proxy/server.py b/libmproxy/proxy/server.py
index 2f6ee061..a45276d4 100644
--- a/libmproxy/proxy/server.py
+++ b/libmproxy/proxy/server.py
@@ -1,13 +1,14 @@
-from __future__ import absolute_import
+from __future__ import absolute_import, print_function
 
+import traceback
+import sys
 import socket
-from OpenSSL import SSL
 
 from netlib import tcp
+from . import layer
 from .primitives import ProxyServerError, Log, ProxyError
 from .connection import ClientConnection, ServerConnection
 from ..protocol.handle import protocol_handler
-from .. import version
 
 
 class DummyServer:
@@ -46,7 +47,7 @@ class ProxyServer(tcp.TCPServer):
         self.channel = channel
 
     def handle_client_connection(self, conn, client_address):
-        h = ConnectionHandler(
+        h = ConnectionHandler2(
             self.config,
             conn,
             client_address,
@@ -56,6 +57,57 @@ class ProxyServer(tcp.TCPServer):
         h.finish()
 
 
+class ConnectionHandler2:
+    # FIXME: parameter ordering
+    # FIXME: remove server attribute
+    def __init__(self, config, client_conn, client_address, server, channel):
+        self.config = config
+        """@type: libmproxy.proxy.config.ProxyConfig"""
+        self.client_conn = ClientConnection(
+            client_conn,
+            client_address,
+            server)
+        """@type: libmproxy.proxy.connection.ClientConnection"""
+        self.channel = channel
+        """@type: libmproxy.controller.Channel"""
+
+    def handle(self):
+        self.log("clientconnect", "info")
+
+        root_context = layer.RootContext(
+            self.client_conn,
+            self.config,
+            self.channel
+        )
+        root_layer = layer.Socks5IncomingLayer(root_context)
+
+        try:
+            for message in root_layer():
+                print("Root layer receveived: %s" % message)
+        except layer.ProxyError2 as e:
+            self.log(e, "info")
+        except Exception:
+            self.log(traceback.format_exc(), "error")
+            print(traceback.format_exc(), file=sys.stderr)
+            print("mitmproxy has crashed!", file=sys.stderr)
+            print("Please lodge a bug report at: https://github.com/mitmproxy/mitmproxy", file=sys.stderr)
+
+    def finish(self):
+        self.client_conn.finish()
+
+    def log(self, msg, level, subs=()):
+        # FIXME: Duplicate code
+        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 ConnectionHandler:
     def __init__(
             self,
@@ -74,6 +126,7 @@ class ConnectionHandler:
         self.server_conn = None
         """@type: libmproxy.proxy.connection.ServerConnection"""
         self.channel = channel
+        """@type: libmproxy.controller.Channel"""
 
         self.conntype = "http"
 
@@ -144,9 +197,9 @@ class ConnectionHandler:
             import sys
 
             self.log(traceback.format_exc(), "error")
-            print >> sys.stderr, traceback.format_exc()
-            print >> sys.stderr, "mitmproxy has crashed!"
-            print >> sys.stderr, "Please lodge a bug report at: https://github.com/mitmproxy/mitmproxy"
+            print(traceback.format_exc(), file=sys.stderr)
+            print("mitmproxy has crashed!", file=sys.stderr)
+            print("Please lodge a bug report at: https://github.com/mitmproxy/mitmproxy", file=sys.stderr)
         finally:
             # Make sure that we close the server connection in any case.
             # The client connection is closed by the ProxyServer and does not
@@ -201,7 +254,7 @@ class ConnectionHandler:
             "serverconnect", "debug", [
                 "%s:%s" %
                 self.server_conn.address()[
-                    :2]])
+                :2]])
         if ask:
             self.channel.ask("serverconnect", self)
         try: