#!/usr/bin/perl -w

use JSON;

opendir(my $dh, "/sys/class/net") or die "Couldn't open /sys/class/net: $!";
my @nics = grep { $_ !~ m/^\./ } readdir($dh);
closedir($dh);
my $json;
foreach my $nic (@nics){
    # Untaint $nic and makes sure the name looks OK
    next unless ($nic =~ m/^(\w+[\.:]?\d+)$/);
    $nic = $1;
    next if (
        # skip non links
        !-l "/sys/class/net/$nic"
    );
    push @{$json->{data}}, { "{#IFNAME}" => $nic};
}
print to_json($json) if (defined $json->{data});
exit(0);