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 ;