# Net::Time.pm # # Copyright (C) 1995-2004 Graham Barr. All rights reserved. # Copyright (C) 2014, 2020 Steve Hay. All rights reserved. # This module is free software; you can redistribute it and/or modify it under # the same terms as Perl itself, i.e. under the terms of either the GNU General # Public License or the Artistic License, as specified in the F<LICENCE> file. package Net::Time; use 5.008001; use strict; use warnings; use Carp; use Exporter; use IO::Select; use IO::Socket; use Net::Config; our @ISA = qw(Exporter); our @EXPORT_OK = qw(inet_time inet_daytime); our $VERSION = "3.13"; our $TIMEOUT = 120; sub _socket { my ($pname, $pnum, $host, $proto, $timeout) = @_; $proto ||= 'udp'; my $port = (getservbyname($pname, $proto))[2] || $pnum; my $hosts = defined $host ? [$host] : $NetConfig{$pname . '_hosts'}; my $me; foreach my $addr (@$hosts) { $me = IO::Socket::INET->new( PeerAddr => $addr, PeerPort => $port, Proto => $proto ) and last; } return unless $me; $me->send("\n") if $proto eq 'udp'; $timeout = $TIMEOUT unless defined $timeout; IO::Select->new($me)->can_read($timeout) ? $me : undef; } sub inet_time { my $s = _socket('time', 37, @_) || return; my $buf = ''; my $offset = 0 | 0; return unless defined $s->recv($buf, length(pack("N", 0))); # unpack, we | 0 to ensure we have an unsigned my $time = (unpack("N", $buf))[0] | 0; # the time protocol return time in seconds since 1900, convert # it to a the required format if ($^O eq "MacOS") { # MacOS return seconds since 1904, 1900 was not a leap year. $offset = (4 * 31536000) | 0; } else { # otherwise return seconds since 1972, there were 17 leap years between # 1900 and 1972 $offset = (70 * 31536000 + 17 * 86400) | 0; } $time - $offset; } sub inet_daytime { my $s = _socket('daytime', 13, @_) || return; my $buf = ''; defined($s->recv($buf, 1024)) ? $buf : undef; } 1; __END__ =head1 NAME Net::Time - time and daytime network client interface =head1 SYNOPSIS use Net::Time qw(inet_time inet_daytime); print inet_time(); # use default host from Net::Config print inet_time('localhost'); print inet_time('localhost', 'tcp'); print inet_daytime(); # use default host from Net::Config print inet_daytime('localhost'); print inet_daytime('localhost', 'tcp'); =head1 DESCRIPTION C<Net::Time> provides subroutines that obtain the time on a remote machine. =head2 Functions =over 4 =item C<inet_time([$host[, $protocol[, $timeout]]])> Obtain the time on C<$host>, or some default host if C<$host> is not given or not defined, using the protocol as defined in RFC868. The optional argument C<$protocol> should define the protocol to use, either C<tcp> or C<udp>. The result will be a time value in the same units as returned by time() or I<undef> upon failure. =item C<inet_daytime([$host[, $protocol[, $timeout]]])> Obtain the time on C<$host>, or some default host if C<$host> is not given or not defined, using the protocol as defined in RFC867. The optional argument C<$protocol> should define the protocol to use, either C<tcp> or C<udp>. The result will be an ASCII string or I<undef> upon failure. =back =head1 EXPORTS The following symbols are, or can be, exported by this module: =over 4 =item Default Exports I<None>. =item Optional Exports C<inet_time>, C<inet_daytime>. =item Export Tags I<None>. =back =head1 KNOWN BUGS I<None>. =head1 AUTHOR Graham Barr E<lt>L<gbarr@pobox.com|mailto:gbarr@pobox.com>E<gt>. Steve Hay E<lt>L<shay@cpan.org|mailto:shay@cpan.org>E<gt> is now maintaining libnet as of version 1.22_02. =head1 COPYRIGHT Copyright (C) 1995-2004 Graham Barr. All rights reserved. Copyright (C) 2014, 2020 Steve Hay. All rights reserved. =head1 LICENCE This module is free software; you can redistribute it and/or modify it under the same terms as Perl itself, i.e. under the terms of either the GNU General Public License or the Artistic License, as specified in the F<LICENCE> file. =head1 VERSION Version 3.13 =head1 DATE 23 Dec 2020 =head1 HISTORY See the F<Changes> file. =cut