基本的上网通道。学习一下实现方法。
简单说起来就是：
在本地，把流量发送到客户端端口，经由本地运行的代理转发到远端。远端执行转发过来的请求。
转发过程中可以加密，因此中间节点难以识别报文的具体信息。
可以看见，http报文承载于tcp，因此浏览器的大部分网页浏览就没有问题了。
客户端的功能主要就是链接的建立过程和加密。如果只实现tcp部分转发，代码并不会很长。
以下代码基于shadowsocks2.9版本。(使用了它的加密库)
#!/usr/bin/python # -*- coding: utf-8 -*- from __future__ import absolute_import, division,\ with_statement import os,sys reload(sys) sys.setdefaultencoding('utf-8') import json import SocketServer import socket import struct import select import binascii sys.path.insert(0, os.path.join(os.path.dirname(__file__), '../')) from shadowsocks import encrypt def send_all(sock, data): bytes_sent = 0 while True: r = sock.sendall(data[bytes_sent:]) #print "r:" + str(r) return len(data) class ThreadingTCPServer(SocketServer.ThreadingMixIn,SocketServer.TCPServer): #class ThreadingTCPServer(SocketServer.TCPServer): #单线程调试时使用 #继承了这两个类第一个类放前面表示优先查找他的方法，而他有多线程的handler #init的方法，在第二个类中找到，于是入参就是端口加RequestHandlerClass #process_request Overridden by ThreadingMixIn. allow_reuse_address = True class Socks5Server(SocketServer.StreamRequestHandler): #继承自Base class for request handler classes，自定义handle方法即可 def encrypt(self, data): return self._encryptor.encrypt(data) def decrypt(self, data): return self._encryptor.decrypt(data) def send_encrypt(self, sock, data): sock.send(self.encrypt(data)) def handle_socks5(self): self._encryptor = encrypt.Encryptor(str(KEY),str(METHOD)) sock = self.connection #self.connection就是最初的socket 经历了request跟connection名字的变化而已 rec = sock.recv(262) #print "AUTHENTICATION :",rec.encode('hex') sock.send("\x05\x00") data = self.rfile.read(4) mode = ord(data[1]) # CMD == 0x01 (connect) if mode != 1: print "\n\n\nerror :mode != 1\n\n\n\n" #1为connect，2bing，3udp return addrtype = ord(data[3]) # indicate destination address type print "mode:" + str(mode) + " addrtype:" + str(addrtype) + " ", addr_to_send = data[3] if addrtype == 1: # IPv4 addr_ip = self.rfile.read(4) # 4 bytes IPv4 address (big endian) addr = socket.inet_ntoa(addr_ip) print "addr_ip:%s" %addr, addr_to_send += addr_ip elif addrtype == 3: # FQDN (Fully Qualified Domain Name) addr_len = self.rfile.read(1) # Domain name's Length addr = self.rfile.read(ord(addr_len)) # Followed by domain name(e.g. www.google.com) addr_to_send += addr_len + addr else: print "\n\n\n\n warning :addr_type not support\n\n\n\n" print "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!\n" print " warning :addr_type not support" return addr_port = self.rfile.read(2) addr_to_send += addr_port # addr_to_send = ATYP + [Length] + dst addr/domain name + port port = struct.unpack('>H', addr_port) # prase the big endian port number. Note: The result is a tuple even if it contains exactly one item. reply = "\x05\x00\x00\x01" # VER REP RSV ATYP reply += socket.inet_aton('0.0.0.0') + struct.pack(">H", 5678) #this port num no important self.wfile.write(reply) # response packet # reply immediately if '-6' in sys.argv[1:]: # IPv6 support remote = socket.socket(socket.AF_INET6, socket.SOCK_STREAM) else: remote = socket.socket(socket.AF_INET, socket.SOCK_STREAM) remote.setsockopt(socket.IPPROTO_TCP, socket.TCP_NODELAY, 1) # turn off Nagling print "addr_to_send:" ,addr_to_send remote.connect((SERVER, REMOTE_PORT)) self.send_encrypt(remote, addr_to_send) # encrypted print "head len",str(len(addr_to_send)) #print "head len",str(len(addr_to_send + (100-len(addr_to_send)) * b'\x00')) #print "send encrypt head len", str(len(self._encryptor.encrypt(addr_to_send + (100-len(addr_to_send)) * b'\x00'))) #print "connecting %s:%d" % (addr, port[0]) self.handle_tcp(sock, remote) def handle_tcp(self,sock, remote): fdset = [sock, remote] while True: #print "handle tcp loop" r, w, e = select.select(fdset, [], []) # use select I/O multiplexing model if sock in r: # if local socket is ready for reading data = sock.recv(4096) #print "sock send data:", len(data), binascii.b2a_hex(data), "*\n", str(data), "#" #print "sock data" + str(data) + "end" if len(data) <= 0: # received all data #print 'sock len' + str(len(data)) break #print 'sock sendall' result = send_all(remote, self.encrypt(data)) # send data after encrypting if result < len(data): pass #print 'len' + str(result) + 'failed to send all data' #raise Exception('failed to send all data sock') if remote in r: # remote socket(proxy) ready for reading data = remote.recv(4096) #print "sock send data:", len(data), hex(self.decrypt(data)[0]),hex(self.decrypt(data)[1]),binascii.b2a_hex(str(self.decrypt(data))), "*\n", str(self.decrypt(data)), "#" if len(data) <= 0: #print 'remote len' + str(len(data)) break #print 'remote sendall' result = send_all(sock, self.decrypt(data)) # send to local socket(application) if result < len(data): pass #print 'failed to send all data remote' #raise Exception('failed to send all data remote') def handle(self): self.handle_socks5() if __name__ == '__main__': os.chdir(os.path.dirname(__file__) or './') with open('config.json', 'rb') as f: config = json.load(f) SERVER = config['server'] REMOTE_PORT = config['server_port'] PORT = config['local_port'] KEY = config['password'] METHOD = config['method'] server = ThreadingTCPServer(('', PORT), Socks5Server) print "server start prot: %d" % PORT server.serve_forever() """serve_forever -> _handle_request_noblock -> process_request -> finish_request -> -> self.RequestHandlerClass(request, client_address, self) -> handle() 所以重写了requestHandlerClass"""
{
"server": "x.x.x.x",
"server_port": x,
"password": "x",
"local_port": x,
"method":"aes-256-cfb"
}from __future__ import absolute_import作用是更好组织文件目录
因此文件放在shadowsocks-2.9.1\shadowsocks下
使用：设置浏览器使用sock5，端口、密码为所设置。部署远端shadowsocks。
windows下需要安装Win64OpenSSL-1_1_0g，linux下同样需要加密库。
实际上shadowsocks的实现复杂多了，还有很多要学习的地方。
运行起来就是这样啦
参考：
https://zhuanlan.zhihu.com/p/28675737
https://loggerhead.me/posts/shadowsocks-yuan-ma-fen-xi-tcp-dai-li.html