package Net::EmptyPort;
use strict;
use warnings;
use base qw/Exporter/;
use IO::Socket::IP;
use Time::HiRes ();
our @EXPORT = qw/ can_bind empty_port check_port wait_port /;
sub can_bind {
my ($host, $port, $proto) = @_;
$port ||= 0;
$proto ||= 'tcp';
my $s = IO::Socket::IP->new(
(($proto eq 'udp') ? () : (Listen => 5)),
LocalAddr => $host,
LocalPort => $port,
Proto => $proto,
V6Only => 1,
(($^O eq 'MSWin32') ? () : (ReuseAddr => 1)),
);
defined $s;
}
# get a empty port on 49152 .. 65535
# http://www.iana.org/assignments/port-numbers
sub empty_port {
my ($host, $port, $proto) = @_ && ref $_[0] eq 'HASH' ? ($_[0]->{host}, $_[0]->{port}, $_[0]->{proto}) : (undef, @_);
$host = '127.0.0.1'
unless defined $host;
if (defined $port) {
$port = 49152 unless $port =~ /^[0-9]+$/ && $port < 49152;
} else {
$port = 50000 + (int(rand()*1500) + abs($$)) % 1500;
}
$proto = $proto ? lc($proto) : 'tcp';
while ( $port++ < 65000 ) {
# Remote checks don't work on UDP, and Local checks would be redundant here...
next if ($proto eq 'tcp' && check_port({ host => $host, port => $port }));
return $port if can_bind($host, $port, $proto);
}
die "empty port not found";
}
sub check_port {
my ($host, $port, $proto) = @_ && ref $_[0] eq 'HASH' ? ($_[0]->{host}, $_[0]->{port}, $_[0]->{proto}) : (undef, @_);
$host = '127.0.0.1'
unless defined $host;
$proto = $proto ? lc($proto) : 'tcp';
# for TCP, we do a remote port check
# for UDP, we do a local port check, like empty_port does
my $sock = ($proto eq 'tcp') ?
IO::Socket::IP->new(
Proto => 'tcp',
PeerAddr => $host,
PeerPort => $port,
V6Only => 1,
) :
IO::Socket::IP->new(
Proto => $proto,
LocalAddr => $host,
LocalPort => $port,
V6Only => 1,
(($^O eq 'MSWin32') ? () : (ReuseAddr => 1)),
)
;
if ($sock) {
close $sock;
return 1; # The port is used.
}
else {
return 0; # The port is not used.
}
}
sub _make_waiter {
my $max_wait = shift;
my $waited = 0;
my $sleep = 0.001;
return sub {
return 0 if $max_wait >= 0 && $waited > $max_wait;
Time::HiRes::sleep($sleep);
$waited += $sleep;
$sleep *= 2;
return 1;
};
}
sub wait_port {
my ($host, $port, $max_wait, $proto);
if (@_ && ref $_[0] eq 'HASH') {
($host, $port, $max_wait, $proto) = ($_[0]->{host}, $_[0]->{port}, $_[0]->{max_wait}, $_[0]->{proto});
} elsif (@_==4) {
# backward compat.
($port, (my $sleep), (my $retry), $proto) = @_;
$max_wait = $sleep * $retry;
} else {
($port, $max_wait, $proto) = @_;
}
$host = '127.0.0.1' unless defined $host;
$max_wait ||= 10;
$proto = $proto ? lc($proto) : 'tcp';
my $waiter = _make_waiter($max_wait);
while ( $waiter->() ) {
if ($^O eq 'MSWin32' ? `$^X -MTest::TCP::CheckPort -echeck_port $port $proto` : check_port({ host => $host, port => $port, proto => $proto })) {
return 1;
}
}
return 0;
}
1;
__END__
=encoding utf8
=head1 NAME
Net::EmptyPort - find a free TCP/UDP port
=head1 SYNOPSIS
use Net::EmptyPort qw(empty_port check_port);
# get a random free port
my $port = empty_port();
# check if a port is already used
if (check_port(5000)) {
say "Port 5000 already in use";
}
=head1 DESCRIPTION
Net::EmptyPort helps finding an empty TCP/UDP port.
=head1 METHODS
=over 4
=item C<< empty_port() >>
=item C<< empty_port(\%args) >>
=item C<< empty_port($port) >>
=item C<< empty_port($port, $proto) >>
my $port = empty_port();
Returns a port number that is NOT in use.
The function recognizes the following keys when given a hashref as the argument.
=over 4
=item C<< host >>
specifies the address on which the search should be performed. Default is C<< 127.0.0.1 >>.
=item C<< port >>
Lower bound of the search for an empty port. If omitted, the function searches for an empty port within 49152..65535.
See L<http://www.iana.org/assignments/port-numbers>
=item C<< proto >>
Name of the protocol. Default is C<< tcp >>. You can find an empty UDP port by specifying C<< udp >>.
=back
To maintain backwards compatibility, the function accepts scalar arguments as well. For example, you can also find an empty UDP port by specifying the protocol as
the second parameter:
my $port = empty_port(1024, 'udp');
# use 49152..65535 range
my $port = empty_port(undef, 'udp');
=item C<< check_port(\%args) >>
=item C<< check_port($port) >>
=item C<< check_port($port, $proto) >>
my $true_or_false = check_port(5000);
Checks if the given port is already in use. Returns true if it is in use (i.e. if the port is NOT free). Returns false if the port is free.
The function recognizes the following keys when given a hashref as the argument.
=over 4
=item C<< host >>
specifies the address on which the search should be performed. Default is C<< 127.0.0.1 >>.
=item C<< port >>
specifies the port to check. This argument is mandatory.
=item C<< proto >>
name of the protocol. Default is C<< tcp >>.
=back
To maintain backwards compatibility, the function accepts scalar arguments as well in the form described above.
=item C<< wait_port(\%args) >>
=item C<< wait_port($port) >>
=item C<< wait_port($port, $max_wait) >>
=item C<< wait_port($port, $max_wait, $proto) >>
Waits until a particular port becomes ready to connect to. Returns true if the port becomes ready, or false if otherwise.
The function recognizes the following keys when given a hashref as the argument.
=over 4
=item C<< host >>
specifies the address on which the search should be performed. Default is C<< 127.0.0.1 >>.
=item C<< port >>
specifies the port to check. This argument is mandatory.
=item C<< max_wait >>
maximum seconds to wait for (default is 10 seconds). Pass a negative value to wait infinitely.
=item C<< proto >>
name of the protocol. Default is C<< tcp >>.
=back
To maintain backwards compatibility, the function accepts scalar arguments as well in the form described above.
B<Incompatible changes>: Before 2.0, C<< wait_port($port:Int[, $sleep:Number, $retry:Int, $proto:String]) >> is a signature.
=item C<< can_bind($host) >>
=item C<< can_bind($host, $port) >>
=item C<< can_bind($host, $port, $proto) >>
Checks if the application is capable of binding to given port.
=back
=head1 AUTHOR
Tokuhiro Matsuno E<lt>tokuhirom@gmail.comE<gt>
=head1 THANKS TO
kazuhooku
dragon3
charsbar
Tatsuhiko Miyagawa
lestrrat
=head1 SEE ALSO
=head1 LICENSE
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut