NTPD上の時間と、LocalTimeとを比較するスクリプトを作ってみた。
結構色んな要素を含んでいて勉強になったかな。
ネットワークバイト列から時間への変換などをunpackを用いて実装する。
#!/usr/bin/perl
use strict;
use Socket;
# Local Time Lag Alart Threshold Seconds
my $threshold_sec = 30;
# NTPD Informations
my $host = 'ntp1.jst.mfeed.ad.jp';
my $protocol = "ntp";
my $sec_of_70years = 2_208_988_800;
# Local Settings
my $hostname = `/bin/hostname`;
chomp($hostname);
my $date = `/bin/date +%Y/%m/%d-%H:%M:%S`;
chomp($date);
# Variable Settings
my @buf;
my ($connect_host, $port, $ipaddr, $host_addr);
my ($send_data, $send_data_byte, $port_by_byte, $host_by_in_addr_struct, $recv_data);
my ($TransmitTime, $ntpd_time, $ntpd_time_sec, $local_time, $local_time_sec, $deley_sec);
if (!socket(SOCKET, PF_INET, SOCK_DGRAM, getprotobyname("udp"))) {
print "socket: $!";
exit 1;
}
$port_by_byte = scalar(getservbyname($protocol, "udp"));
$host_by_in_addr_struct = inet_aton($host);
$connect_host = sockaddr_in($port_by_byte, $host_by_in_addr_struct);
$send_data = pack("N12", 0x0B000000);
$send_data_byte = send(SOCKET, $send_data, 0, $connect_host);
if (!defined($send_data_byte)) {
print "send : $!";
exit 2;
}
$host_addr = recv(SOCKET, $recv_data, 1024, 0);
if (!defined($host_addr)) {
print "recv : $!";
exit 3;
}
($port, $ipaddr) = sockaddr_in($host_addr);
$host = gethostbyaddr($ipaddr, AF_INET);
print "DEBUG: Host: $host, Port: $port\n";
@buf = unpack("B32 B32 B32 B32 B64 B64 B64 B64 B*", $recv_data);
@buf = unpack("N*" , $recv_data);
$TransmitTime = $buf[10];
$ntpd_time_sec = $TransmitTime - $sec_of_70years;
$local_time_sec = time();
$deley_sec = abs($local_time_sec - $ntpd_time_sec);
# DEBUG
$ntpd_time = scalar(localtime($ntpd_time_sec));
$local_time = scalar(localtime());
print "DEBUG: ntpd? time: $ntpd_time.???? ntpd? time sec: $ntpd_time_sec\n";
print "DEBUG: local time: $local_time.???? local time sec: $local_time_sec\n";
if ($deley_sec >= $threshold_sec) {
print "DEBUG: There is Local time lag ( = $deley_sec seconds ) over $threshold_sec seconds in $date at $hostname.\n";
}
実行結果はこんな感じ。
# perl a
DEBUG: Host: ntp1.jst.mfeed.ad.jp, Port: 123
DEBUG: ntpd time: Wed Mar 11 22:43:06 2009. ntpd time sec: 1236778986
DEBUG: local time: Wed Mar 11 22:41:23 2009. local time sec: 1236778883
DEBUG: There is Local time lag ( = 103 seconds ) over 30 seconds in 2009/03/11-22:41:23 at server01.
