Perl脚本实现检测主机心跳信号功能

使用串口通信，在备机端使用如下脚本检测来自主机的心跳信号，一旦未接受次数超过指定记数，备机认为主机DOWN机，自动设置为主机的网络参数，顶替主机提供服务。

# ! perl -w 

 use strict;
 use Win32 :: SerialPort;

 my  $port  =  ' COM2 ' ; # serail port name registried in OS
 my  $count  =  0 ; # count number of heartbeat-receiving failture
 my  $max_count  =  5 ; # max fail count to be tolerated
 my  $interface  =  ' 

# ----------------------------------
# 接口 IP 配置
# ----------------------------------
pushd interface ip

# "local" 的接口 IP 配置

set address name="local" source=static addr=192.168.6.185 mask=255.255.255.0
set address name="local" gateway=192.168.6.65 gwmetric=0
set dns name="local" source=static addr=192.168.6.112 register=PRIMARY
add dns name="local" addr=192.168.6.201 index=2
set wins name="local" source=static addr=none

popd
# 接口 IP 配置结束

 ' ; # net inetrface config information 

 sub errlog {
   # log the failtrue occuring time 

   open ERR ,  ' >>err.log ' ;
   my  @time  =  localtime ();
   my  $time  =  sprintf ( " %d " ,  $time [ 5 ] +  1900 )
             .  ' - '
             .  sprintf ( " %d " ,  $time [ 4 ] +  1 )
             .  ' - '
             .  " $time[3] "
             .  '  '
             .  sprintf ( " %.2d " ,  $time [ 2 ])
             .  ' : '
             .  sprintf ( " %.2d " ,  $time [ 1 ])
             .  ' : '
             .  sprintf ( " %.2d " ,  $time [ 0 ]);
   print ERR $time . " \n " ;
   close ERR;
}

 sub ipchange {
   # change ip addrress 

   open TMP ,  ' >tmp ' ;
   print TMP $interface ;
   close TMP;

   eval {
     system  ' netsh -f tmp ' ;
     unlink  ' tmp ' ;
  };

   if ($@) { return  0 ;}
   return  1 ;
}

 my  $ob  = Win32 :: SerialPort -> new( $port ) or die  " CANNOT OPEN $port " ;
 # open serial port 

 eval {
   # set serial port properties 

   $ob -> baudrate( 9600 );
   $ob -> parity( ' none ' );
   $ob -> databits( 8 );
   $ob -> stopbits( 1 );
   $ob -> handshake( ' none ' );
};

 if ($@) { die  ' SET FAILED ' ;}

 $ob -> write_settings or die  " CANNOT WRITE $port DRIVER " ;
 # write to port driver to make it active 

 while ( 1 ) {
   # loop receiving heartbeat from remote machine
  # change ip address after designated count of failture 

   my ( $length ,  $result ) =  $ob -> read ( 10 );

   if ( $result ) {
     $count  =  0 ;
  } elsif ( $count  ==  $max_count ) {
    errlog();
     if (not ipchange()) { print  ' IP CHANGE FAILED ' ; }
     last ;
  }   else {
     $count ++ ;
  }

   sleep ( 1 );
}

 undef  $ob ;