用Python实现TCP代理

依旧是Python黑帽子这本书

先附上代码，我在原书代码上加了注释，更好理解

import sys
import socket
import threading#生成可打印字符映射
HEX_FILTER=''.join([(len(repr(chr(i)))==3) and chr(i) or '.' for i in range(256)])#接收bytes或string类型的输入，并将其转换为十六进制格式输出
#数值存储
def hexdump(src,length=16,show=True):if isinstance(src,bytes):src=src.decode()results=list()for i in range(0,len(src),length):word=str(src[i:i+length])printable=word.translate(HEX_FILTER)hexa=' '.join([f'{ord(c):02X}' for c in word])hexwidth=length*3results.append(f'{i:04x} {hexa:<{hexwidth}} {printable}')if show:for line in results:print(line)else:return results#接收本地或远程数据
def receive_from(connection):buffer=b""connection.settimeout(5)try:while True:data=connection.recv(4096)if not data:breakbuffer +=dataexcept Exception as e:passreturn buffer#数据处理函数
#预留数据修改的钩子，可以在这里修改客户端请求或服务器响应
def request_handler(buffer):return bufferdef response_handler(buffer):return buffer#代理处理，负责处理客户端与远程服务器间的通信，是代理的核心
def proxy_handler(client_socket,remote_host,remote_port,receive_first):#创建远程连接remote_socket=socket.socket(socket.AF_INET,socket.SOCK_STREAM)#创建TCP连接remote_socket.connect((remote_host,remote_port))#连接到远程服务器#接收远程服务器数据if receive_first:remote_buffer=receive_from(remote_socket)hexdump(remote_buffer)#处理服务器返回数据remote_buffer=response_handler(remote_buffer)if len(remote_buffer):print("[<==] Sending %d bytes to localhost." % len(remote_buffer))client_socket.send(remote_buffer)#循环监听客户端与服务器间的通信，直到连接关闭while True:#处理客户端数据local_buffer=receive_from(client_socket)#读取数据if len(local_buffer):line= "[==>]Received %d bytes from localhost." % len(local_buffer)print(line)#打印数据hexdump(local_buffer)local_buffer=request_handler(local_buffer)#数据修改remote_socket.send(local_buffer)#转发给远程服务器print("[==>]Sent to remote.")#处理远程服务器返回的数据remote_buffer=receive_from(remote_socket)if len(remote_buffer):print("[<==] Received %d bytes from remote." % len(remote_buffer))hexdump(remote_buffer)remote_buffer=response_handler(remote_buffer)client_socket.send(remote_buffer)print("[<==] Sent to localhost.")#关闭连接if not len(local_buffer) or not len(remote_buffer):client_socket.close()remote_socket.close()print("[*] No more data. Closing connections.")#服务器监听
def server_loop(local_host, local_port, remote_host, remote_port, receive_first):#创建socket并绑定端口server = socket.socket(socket.AF_INET, socket.SOCK_STREAM)try:server.bind((local_host, local_port))except Exception as e:print('problem on bind: %r' % e)print("[!!] Failed to listen on %s:%d" % (local_host, local_port))print("[!!] Check for other listening sockets or correct permissions.")sys.exit(0)#监听并等待客户端连接print("[*] Listening on %s:%d" % (local_host, local_port))server.listen(5)while True:#处理客户端连接client_socket, addr = server.accept()#输出连接信息line = "> Received incomming connection from %s:%d" % (addr[0], addr[1])print(line)#启动代理线程proxy_thread = threading.Thread(target=proxy_handler,args=(client_socket, remote_host,remote_port, receive_first))proxy_thread.start()def main():if len(sys.argv[1:]) != 5:print("Usage: ./proxy.py [localhost] [localport]", end='')print("[remotehost] [remoteport] [receive_first]")print("Example: ./proxy.py 127.0.0.1 9000 10.12.132.1 9000 True")sys.exit(0)local_host = sys.argv[1]local_port = int(sys.argv[2])remote_host = sys.argv[3]remote_port = int(sys.argv[4])receive_first = sys.argv[5]if "True" in receive_first:receive_first = Trueelse:receive_first = False#启动服务器server_loop(local_host, local_port, remote_host, remote_port, receive_first)if __name__ == '__main__':main()

windows物理机和kali我都试了，不知道为什么只有kali能用

sudo python TCP_proxy.py 192.168.65.128 8887 www.baidu.com 80 True

再另起一个终端，输入：

curl -x 192.168.65.128:8887 www.baidu.com

这时候我们的脚本就会接收到数据，并以hex的形式输出

本来原书用的是ftp，但是我怎么也复现不出来，只能简单用这个代替一下的，但是原理也差不了太多

但是我发现这个似乎不太稳定，我也是试了两次才成功的

还有个问题就是程序没加入ctrl+c退出的功能，虽然我也懒得加了喵（