#!/usr/bin/perl use strict; use warnings; use Data::Dumper; use Net::SNTP::Client qw ( getSNTPTime ); my %hashInput = ( -hostname => "127.0.0.1", -port => 12345, -RFC4330 => "1", -clearScreen => "1", ); my ( $error , $hashRefOutput ) = getSNTPTime( %hashInput ); print Dumper $hashRefOutput; print "Error: $error\n" if ($error); #### #!/usr/bin/perl use strict; use warnings; use Data::Dumper; use lib '/home/user/Desktop/Net-SNTP-Server-0.01/lib/'; # note here use Net::SNTP::Server qw ( basicSNTPSetup ); my %hashInput = ( -ip => "127.0.0.1", -port => 12345, ); my ( $error , $hashRefOutput ) = basicSNTPSetup( %hashInput ); print Dumper $hashRefOutput; print "Error: $error\n" if ($error); #### package Net::SNTP::Server; ## Validate the version of Perl BEGIN { die 'Perl version 5.6.0 or greater is required' if ($] < 5.006); } use strict; use warnings; =head1 NAME Net::SNTP::Server - Perl Module SNTP Server based on L =head1 VERSION Version 0.01 =cut ## Version of the Net::SNTP::Server module our $VERSION = '0.01'; $VERSION = eval $VERSION; use IO::Socket::INET; use Time::HiRes qw( gettimeofday CLOCK_REALTIME clock_getres ); ## Handle importing/exporting of symbols use Exporter 5.57 qw( import ); # Because I am using an earlier version of Perl 5.8.2 our @EXPORT_OK = qw( basicSNTPSetup ); # symbols to export on request =head1 SYNOPSIS The Net::SNTP::Server - Perl module has the ability to retrieve the time from the local internal clock of the OS. The module has been tested on LinuxOS but it should be compatible with MacOS and WindowsOS. When the server is activated, it will enter while state mode and wait for client requests. The SNTP server uses the local time in seconds and nano seconds accuracy based on the OS accuracy ability. The server will encode a message format based on RFC4330 that will be send to the client in-order to calculate the round-trip delay d and system clock offset. use Net::SNTP::Server; my ( $error , $hashRefOutput ) = basicSNTPSetup( %hashInput ); ... =head1 ABSTRACT The module receives and sends a UDP packet formated according to L message format. The server expects an SNTP packet from the client which will reply back to him. The received packet, gets decoded into a human readable form. As a second step the server extracts and adds the needed data to create the packet. Before the message to be sent to the client it gets encoded and transmitted back to the recipient. =head1 DESCRIPTION This module exports a single method (basicSNTPSetup) and returns an associative hash based on the user input and a string in case of an error. The response from the SNTP server is been encoded to a human readable format. The obtained information received from the server on the client side can be used into further processing or manipulation according to the user needs. Maximum accuracy down to nano seconds can only be achieved based on different OS. =head2 EXPORT my %hashInput = ( -ip => $ip, # IP -port => $port, # default NTP port 123 ); my ( $error , $hashRefOutput ) = basicSNTPSetup( %hashInput ); =over 4 =item * IP -ip: Is not a mandatory for the method key to operate correctly. By default the module will assign the localhost IP ("127.0.0.1"), but this will restrict the server to localhost communications (only internally it can receive and transmit data). =item * PORT -port: Is a mandatory key, that the user must define. By default the port is not set. The user has to specify the port. We can not use the default 123 NTP due to permission. The user has to choose a port number identical to port that the client will use client to communicate with the server (e.g. -port => 123456). =back =head1 SUBROUTINES/METHODS my ( $error , $hashRefOutput ) = basicSNTPSetup( %hashInput ); =cut ## Define constands use constant { TRUE => 1, FALSE => 0, MAXBYTES => 512, ARGUMENTS => 1, UNIX_EPOCH => 2208988800, MIN_UDP_PORT => 1, MAX_UDP_PORT => 65535, DEFAULT_LOCAL_HOST_IP => "127.0.0.1", }; sub basicSNTPSetup { my $error = undef; my $rcvSntpPacket = undef; my ( $rcv_sntp_packet , $server_precision ); my %moduleInput = @_; my %moduleOutput = (); return ($error = "Not defined IP", \%moduleInput) if (!$moduleInput{-ip}); return ($error = "Not defined Port", \%moduleInput) if (!$moduleInput{-port}); return ($error = "Not defined key(s)", \%moduleInput) if (checkHashKeys(%moduleInput)); return ($error = "Not correct port number", \%moduleInput) if (verify_port($moduleInput{-port})); my ( @array_IP ) = ( $moduleInput{-ip} =~ /(\d{1,3})\.(\d{1,3})\.(\d{1,3})\.(\d{1,3})/ ); return ($error = "Not correct input IP syntax", \%moduleInput) if ( (!defined $array_IP[0]) || (!defined $array_IP[1]) || (!defined $array_IP[2]) || (!defined $array_IP[3]) ); # Convert IP my $server_reference_identifier_hex .= dec_2_hex( @array_IP ); my $server_socket; eval { $server_socket = IO::Socket::INET->new( LocalAddr => $moduleInput{-ip} || DEFAULT_LOCAL_HOST_IP, LocalPort => $moduleInput{-port}, # Mandatory, we can't use NTP default 123 Proto => 'udp', Type => SOCK_DGRAM, Broadcast => 1 ) or die "Error Creating Socket"; }; return ($error = "Problem While Creating Socket '$!'", \%moduleInput) if ( $@ && $@ =~ /Error Creating Socket/ ); print "\n[Server $0 listens at PORT: ".$moduleInput{-port}." and IP: ".$moduleInput{-ip}."]\n\n"; while ( TRUE ) { # Reference Timestamp: This field is the time the system clock was last # set or corrected, in 64-bit timestamp format. (assumption of time synchronization) my ( $server_reference_timestamp_sec, $server_reference_timestamp_microsec ) = gettimeofday(); my $peer_address = $server_socket->peerhost(); my $peer_port = $server_socket->peerport(); if ( $peer_address ) { print "Peer address: ".$peer_address."\n" }; if ( $peer_port ) { print "Peer port: ".$peer_port."\n" }; eval { $server_socket->recv( $rcv_sntp_packet , MAXBYTES ) or die "Error Receiving"; }; return ($error = "Problem While Receiving '$!'", \%moduleInput) if ( $@ && $@ =~ /Error Receiving/ ); # $server_rcv_timestamp_sec (originate time rcv by server sec) # 32 bit # $server_rcv_timestamp_microsec (originate time rcv by server microsec) # 32 bit my ( $server_rcv_timestamp_sec, $server_rcv_timestamp_microsec ) = gettimeofday(); my @arrayRcvSntpPacket = unpack( "B8 C3 N11" , $rcv_sntp_packet ); my ( $client_li_vn_mode, $client_stratum, $client_poll, $client_precision, $client_root_delay, $client_dispersion, $client_reference_identifier, $client_reference_timestamp_sec, $client_reference_timestamp_microsec, $client_originate_timestamp_sec, $client_originate_timestamp_microsec, $client_receive_timestamp_sec, $client_receive_timestamp_microsec, $client_transmit_sec, $client_transmit_microsec ) = @arrayRcvSntpPacket; # Server data preparing message # $li = 00 2 bit = value 0 no warning # $vn = 100 3 bit = Value 4 IPV4 # $mode = 100 3 bit = Value 4 server mode my $server_li_vn_mode = '00100100'; my $server_stratum = '00000010'; # Stratum is 3 because my $server_poll_interval = 3; # Poll interval is 6 # The precission size on the RFC is 8 bits, anything lower # than 1e-03 (0.001) it can not fit on 8 bits. In such cases # we round to clossest digit. Never the less the value is so # small not even worth mentioning it. if ( $^O eq 'MSWin32' ) { ( undef , undef , $server_precision , undef , undef ) = POSIX::times() ; } else { $server_precision = clock_getres( CLOCK_REALTIME ); } my $server_root_delay_sec = '0'; # 16 bit my $server_root_delay_microsec = '0'; # 16 bit my $server_dispersion_sec = '0'; # 16 bit my $server_dispersion_microsec = '0'; # 16 bit $server_reference_timestamp_sec += UNIX_EPOCH; $server_rcv_timestamp_sec += UNIX_EPOCH; # $server_transmit_timestamp_sec (originate time rcv by server sec) # 32 bit # $server_transmit_timestamp_microsec (originate time rcv by server microsec) # 32 bit my ( $server_transmit_timestamp_sec, $server_transmit_timestamp_microsec ) = gettimeofday(); $server_transmit_timestamp_sec += UNIX_EPOCH; my @arraySendSntpPacket = ( $server_li_vn_mode, $server_stratum, $server_poll_interval, $server_precision, $server_root_delay_sec, $server_root_delay_microsec, $server_dispersion_sec, $server_dispersion_microsec, $server_reference_identifier_hex, $server_reference_timestamp_sec, $server_reference_timestamp_microsec, $client_transmit_sec, $client_transmit_microsec, $server_rcv_timestamp_sec, $server_rcv_timestamp_microsec, $server_transmit_timestamp_sec, $server_transmit_timestamp_microsec ); my $send_sntp_packet = pack( "B8 C3 n B16 n B16 H8 N8" , @arraySendSntpPacket ); eval { $server_socket->send( $send_sntp_packet ) or die "Error Sending"; }; return ($error = "Problem While Sending '$!'", \%moduleInput) if ( $@ && $@ =~ /Error Sending/ ); } # End of while(TRUE) loop $server_socket->close(); # Close socket return $error, \%moduleOutput; } sub dec_2_hex { my ( @decimal_IP ) = @_; my $hex = join( '', map { sprintf '%02X', $_ } $decimal_IP[0], $decimal_IP[1], $decimal_IP[2], $decimal_IP[3]); return ( uc( $hex ) ); } sub checkHashKeys { my @keysToCompare = ( "-ip", "-port" ); my %hashInputToCompare = @_; my @hashInputKeysToCompare = keys %hashInputToCompare; local *keyDifference = sub { my %hashdiff = map{ $_ => 1 } @{$_[1]}; return grep { !defined $hashdiff{$_} } @{$_[0]}; }; my @differendKeys = keyDifference(\@hashInputKeysToCompare, \@keysToCompare); # c - style if condition return TRUE ? @differendKeys : return FALSE; # Or if (@differendKeys) { return TRUE } else { return FALSE }; } sub verify_port { my $port = shift; if ( defined $port && $port =~ /^[0-9]+$/ ) { if ( $port >= MIN_UDP_PORT && MAX_UDP_PORT >= $port ) { return FALSE; } } return TRUE; } =head1 EXAMPLE This example starts a remote NTP server based on RFC4330 message format. The IP and Port that the user will provide based on his criteria. We use the L module to print the output if needed. The module does not require to printout the output. It should be used only for initialization purposes to assist the user with debugging in case of an error. The $error string it is also optional that will assist the user to identify the root that can cause a faulty initialization. #!/usr/bin/perl use strict; use warnings; use Data::Dumper; use Net::SNTP::Server qw(basicSNTPSetup); my %hashInput = ( -ip => "127.0.0.1", -port => 12345, ); my ( $error , $hashRefOutput ) = basicSNTPSetup( %hashInput ); print Dumper $hashRefOutput; print "Error: $error\n" if ($error); =head1 AUTHOR Athanasios Garyfalos, C<< >> =head1 BUGS Please report any bugs or feature requests to C, or through the web interface at L. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes. =head1 SUPPORT You can find documentation for this module with the perldoc command. perldoc Net::SNTP::Server You can also look for information at: =over 4 =item * RT: CPAN's request tracker (report bugs here) L =item * AnnoCPAN: Annotated CPAN documentation L =item * CPAN Ratings L =item * Search CPAN L =back =head1 ACKNOWLEDGEMENTS I want to say thank you to L for their guidance and assistance when ever I had a problem with the implementation process of module. =head1 LICENSE AND COPYRIGHT Copyright 2015 Athanasios Garyfalos. This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at: L Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license. If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license. This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder. This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed. Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. =head1 CHANGE LOG $Log: Server.pm,v $ Revision 1.0 2015/07/17 16:32:31 Thanos =cut 1; # End of Net::SNTP::Server