1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
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")
|
