使用php来实现telnet的连接、传递命令、获取返回值等功能！

telnet.php

<?php  error_reporting(-1);    class Telnet {   var $sock = NULL;     function telnet($host,$port) {    $this->sock = fsockopen($host,$port);    socket_set_timeout($this->sock,2,0);   }     function close() {    if ($this->sock)  fclose($this->sock);    $this->sock = NULL;   }     function write($buffer) {    $buffer = str_replace(chr(255),chr(255).chr(255),$buffer);    fwrite($this->sock,$buffer);   }     function getc() {    return fgetc($this->sock);    }     function read_till($what) {    $buf = '';    while (1) {     $IAC = chr(255);       $DONT = chr(254);     $DO = chr(253);       $WONT = chr(252);     $WILL = chr(251);       $theNULL = chr(0);       $c = $this->getc();       if ($c === false) return $buf;     if ($c == $theNULL) {      continue;     }       if ($c == "1") {      continue;     }       if ($c != $IAC) {      $buf .= $c;        if ($what == (substr($buf,strlen($buf)-strlen($what)))) {       return $buf;      }      else {       continue;      }     }       $c = $this->getc();       if ($c == $IAC) {     $buf .= $c;     }     else if (($c == $DO) || ($c == $DONT)) {      $opt = $this->getc();      // echo "we wont ".ord($opt)."\n";      fwrite($this->sock,$IAC.$WONT.$opt);     }     elseif (($c == $WILL) || ($c == $WONT)) {      $opt = $this->getc();      // echo "we dont ".ord($opt)."\n";      fwrite($this->sock,$IAC.$DONT.$opt);     }     else {      // echo "where are we? c=".ord($c)."\n";     }    }   }  }    /*  ʹ�÷��� ʾ��  $telnet = new telnet("192.168.0.1",23);  echo $telnet->read_till("login: ");  $telnet->write("kongxx\r\n");  echo $telnet->read_till("password: ");  $telnet->write("KONGXX\r\n");  echo $telnet->read_till(":> ");  $telnet->write("ls\r\n");  echo $telnet->read_till(":> ");  echo $telnet->close();    */