这里就是使用Python简单的实现一个二级代理。

#coding=utf-8 
import socket 
import select 
import sys 
import threading
import time
import logging
import os
logsDir = "logs"
if not os.path.isdir(logsDir):
    os.mkdir(logsDir)
    
logging.basicConfig(level=logging.DEBUG,
                format='%(asctime)s %(filename)s[line:%(lineno)d] %(levelname)s %(message)s',
                datefmt='%a, %d %b %Y %H:%M:%S',
                filename='logs/logs.log',
                filemode='a')
 
#C的IP和端口 
to_addr = ('127.0.0.1', 8087)


maxConnetions = 32
class Proxy: 
    def __init__(self, addr): 
        self.proxy = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
        self.proxy.bind(addr) 
        self.proxy.listen(maxConnetions) 
        self.inputs = {self.proxy:None} 
        self.route = {} 
   
    def serve_forever(self): 
        logging.info('proxy listen...')
        while 1: 
            readable, _, _ = select.select(list(self.inputs.keys()), [], []) 
            for self.sock in readable: 
                if self.sock == self.proxy: 
                    self.on_join() 
                else:
                    try:
                        data = self.sock.recv(8192)
                    except Exception, e:
                        logging.error(str(e))
                        self.on_quit()
                        continue
                    
                    if not data: 
                        self.on_quit() 
                    else:
                        try:
                            self.route[self.sock].send(data)
                        except Exception, e:
                            logging.error(str(e))
                            self.on_quit()
                            continue
   
    def on_join(self): 
        client, addr = self.proxy.accept() 
        logging.info("proxy client " + str(addr) + 'connect')
        forward = socket.socket(socket.AF_INET, socket.SOCK_STREAM) 
        try:
            forward.connect(to_addr)
        except Exception, e:
            logging.error(str(e))
            client.close()
            return
        self.inputs [client] = None
        self.inputs [forward] = None


        self.route[client] = forward 
        self.route[forward] = client 
    
    #删除连接
    def on_quit(self):
        ls = [self.sock]
        if self.sock in self.route:
            ls.append(self.route[self.sock])
        for s in ls:
            if s in self.inputs:
                del self.inputs[s]
            if s in self.route:
                del self.route[s] 
            s.close() 
            
if __name__ == "__main__":
    try: 
        Proxy(('', 8192)).serve_forever()
    except KeyboardInterrupt, e: 
        logging.error("KeyboardInterrupt" + str(e))