#!/usr/bin/perl -w
#
#  Displays currently connected network interfaces.
#  Lets you DISABLE/REENABLE an interface (eg. if it's not responding)
#
#  2014-02-26  golux -- created.
##


###############
## Libraries ##
###############
use strict;
use warnings;
use File::Basename;
use Data::Dumper;
use Getopt::Long;


##################
## User-defined ##
##################
my $ipconfig   = 'C:\Windows\System32\ipconfig.exe';
my $netsh      = 'C:\Windows\System32\netsh.exe';
my $maxwidth   = 12;
my $re_addr    = qr/^(\d+)[.](\d+)[.](\d+)[.](\d+)(?:)?$/;
my $re_vm      = qr/VMware Network Adapter/i;
my $re_dots    = qr/[\s.]*:\s*/;
my $re_if      = qr/^\s*([\sa-z0-9]+):\s*$/i;
my $re_ip_addr = qr/IP Address:\s*(\d+[.]\d+[.]\d+[.]\d+)/i;

# Order of tags presented
my $a_items = [qw[ desc dhcp state mac addr addr6 mask gate dns ]];

# Label used for each tag
my $h_label = {
	'desc'  => 'Desc',
	'state' => 'State',
	'dhcp'  => 'DHCP',
	'mac'   => 'MAC',
	'addr'  => 'IP Addr',
	'addr6' => 'IPv6 Addr',
	'mask'  => 'Mask',
	'gate'  => 'Gateway',
	'dns'   => 'DNS Suffix',
};

# Regex used to capture the value for each tag
my $h_regex   = {
	'desc'   => qr/^\s*Description${re_dots}(.+)/i,
	'state'  => qr/^\s*Media State${re_dots}(.+)/i,
	'dhcp'   => qr/^\s*Dhcp Enabled${re_dots}(\S+)/i,
	'mac'    => qr/^\s*Physical Address${re_dots}(\S+)/i,
	'addr'   => qr/^\s*IP(?:v4)? Address${re_dots}(\S+)/i,
	'addr6'  => qr/^\s*IPv6 Address${re_dots}(\S+)/i,
	'mask'   => qr/^\s*Subnet Mask${re_dots}(\S+)/i,
	'gate'   => qr/^\s*Default Gateway${re_dots}(\S+)/i,
	'dns'    => qr/^\s*Connection-specific DNS Suffix${re_dots}(\S+)/i,
};


#############
## Globals ##
#############
my $b_all  = 0;
my $b_vms  = 0;
my $b_help = 0;


##################
## Command-line ##
##################
Getopt::Long::Configure("bundling");
my $go = GetOptions(
	"a"  => \$b_all,
	"v"  => \$b_vms,
	"h"  => \$b_help,
);


##################
## Main Program ##
##################
$| = 1;
my $iam = basename $0;

$b_help and give_help();

my $a_args  = [ @ARGV ];
my $a_info  = get_config_info();

if (@$a_args > 0) {
	change_inteface_states($a_info, $a_args);
	$a_info = get_config_info();
}

show_basic_info();
show_interface_info($a_info);


#################
## Subroutines ##
#################
sub fatal {
	my ($msg) = @_;

	my $lnum = (caller)[2];
	my $text = "($iam)  FATAL[$lnum]:  $msg";
	die "$text\n";
}


sub give_help {
	my $syntax = qq{
		:  Syntax:  $iam  [switches]  [command ...]
		:
		:  This program shows the currently connected network interfaces.
		:
		:  To cycle a network interface #N  (disable, then enable it again),
		:  use the command '$iam ~N'.
		:
		:  Switches
		:      -a ... display all interfaces (even disconnected ones)
		:      -v ... display virtual (ie. VMware) interfaces
		:      -h ... display help message and exit
	};

    $syntax =~ s/(^\s+:)|((?<=\n)\s+:)|(\s+$)//g;
	die "$syntax\n";
}


sub get_config_info {
	chomp(my @lines = `$ipconfig /all`);

	my $a_info = [ ];
	my $h_if   = { };

	HANDLE_LINE: 
	foreach my $line (@lines) {
		$line =~ /^\s*$/ and next;
		if ($line =~ /$re_if/) {
			my $if = $1;
			(my $name = $if) =~ s/^Ethernet adapter\s*//i;
			$h_if = { 'if' => $if, 'name' => $name };
			push @$a_info, $h_if;
			next;
		}

		foreach my $item (@$a_items) {
			if ($line =~ /$h_regex->{$item}/) {
				$h_if->{$item} = $1;
				next HANDLE_LINE;
			}
		}
	}

	return prune_results($a_info);
}


sub prune_results {
	my ($a_info) = @_;

	my $a_pruned = [ ];

	for (my $i = 0; $i < @$a_info; $i++) {
		my $idx     = $i + 1;
		my $h_if    = $a_info->[$i];
		my $addr    = $h_if->{'addr'} || "";
		my $name    = $h_if->{'name'} || "";
		my $b_is_vm = ($name =~ /$re_vm/)? 1: 0;
		my $b_conn  = 0;

		$addr =~ s/\(Preferred\)//;
		if ($addr =~ /$re_addr/) {
			($1 or $2 or $3 or $4) and $b_conn = 1;
		}

		$h_if->{'conn'} = $b_conn;

		if ($b_all or ($b_conn and ($b_vms or !$b_is_vm))) {
			push @$a_pruned, $h_if;
		}
	}

	return $a_pruned;
}


sub show_basic_info {
	my $a_conn = [ ];

	for (my $i = 0; $i < @$a_info; $i++) {
		my $idx    = $i + 1;
		my $h_if   = $a_info->[$i];
		my $b_conn = $h_if->{'conn'} || 0;
		$b_conn and push @$a_conn, $idx;
	}

	my $conn = (0 == @$a_conn)? "(none)": join(", ", @$a_conn);

	print "\n";
	my $cname   = $ENV{'COMPUTERNAME'}   || "";
	my $domain  = $ENV{'ComputerDomain'} || "";
	my $user    = $ENV{'USERNAME'}       || "";
	print " ------------------------------------------------\n";
	$cname  and print "    Computer .... $cname\n";
	$domain and print "    Domain ...... $domain\n";
	$user   and print "    User ........ $user\n";
	$conn   and print "    Connected ... $conn\n";
	print " ------------------------------------------------\n";
	print "    Type '$iam -h' for help\n";
	print "\n";
}


sub show_interface_info {
	my ($a_info) = @_;

	my $space  = "   ";

	for (my $i = 0; $i < @$a_info; $i++) {
		my $h_if = $a_info->[$i];
		my $idx  = $i + 1;
		my $if   = $h_if->{'if'};
		printf " #%d [$if]\n", $idx;

		foreach my $item (@$a_items) {
			if (my $val = $h_if->{$item} || "") {
				($item eq 'mac') and $val =~ s/-/:/g;
				my $label = $h_label->{$item} || " ";
				$label or fatal("No label found for item '$item'");
				my $dots = "." x ($maxwidth - length($label));
				printf "$space %s %s %s\n", $label, $dots, $val;
			}
		}

		print "\n";
	}
}


sub change_inteface_states {
	my ($a_info, $a_args) = @_;

	my $nifs = @$a_info;

	foreach my $arg (@$a_args) {
		if ($arg !~ /^~(\d+)$/) {
			print "Invalid arg '$arg' ignored\n";
		} else {
			my $idx = $1;
			if ($idx < 1 or $idx > $nifs) {
				print "Skipping interface '$idx' (not in range 1-$nifs)\n";
			} else {
				my $h_if = $a_info->[$idx-1];
				my $name = $h_if->{'name'};
				cycle_network_interface($name);
			}
		}
	}

	print "\n\n";
}


sub cycle_network_interface {
	my ($name) = @_;

	print "Type [RETURN] to DISABLE, then ENABLE interface '$name':";
	<STDIN>;

	my $netsh_dis  = qq{interface set interface "$name" DISABLED};
	my $netsh_en   = qq{interface set interface "$name" ENABLED};
	my $netsh_show = qq{interface ip show addresses "$name"};

	print "Command:  netsh $netsh_dis\n";
	system("$netsh $netsh_dis 1>nul 2>nul");

	print "Command:  netsh $netsh_en\n";
	system("$netsh $netsh_en 1>nul 2>nul");

	my $ntries  = 32;
	my $addr    = "";
	print "Renewing IP address ";

	while ($ntries-- > 0) {
		print ".";
		chomp(my @results = `$netsh $netsh_show`);
		map { /$re_ip_addr/ and $addr = $1 } @results;
		$addr and last;
		select(undef, undef, undef, 0.25);
	}

	print "\n";
	$addr or fatal("Failed to reenable interface '$name'");
}