#!/usr/bin/perl

use strict;
use warnings;
#use Data::Dumper;

$\ = "\n";
my $list = `netstat -tpn 2> /dev/null`;
my ($line, $processes, @line_elem, $pid, $proc, $port);
while ($list =~ /^(tcp.*?)$/gm)
{
    $line = $1;
    @line_elem = split /\s+/, $line;
    next if $line_elem[6] eq '-';
    ($pid, $proc) = split /\//, $line_elem[6];
    $port = (split /:/, $line_elem[3])[1];
    unless (defined $processes->{$pid}[$port])
    {
        push @{$processes->{$pid}}, $port;
    }
}

# XML
my $xml = '<NETSTAT>';
for $pid (keys %$processes)
{
    $xml .= "<PID pid='$pid'><PORTS>";
    my $i = 1;
    for $port (@{$processes->{$pid}})
    {
        $xml .= "<PORT$i>" . $port . "</PORT$i>";
        $i++;
    }
    $xml .= '</PORTS></PID>';
}
$xml .= '</NETSTAT>';
print $xml;

<NETSTAT>
  <PID pid="2252">
    <PORTS>
      <PORT1>54836</PORT1>
    </PORTS>
  </PID>
  <PID pid="2320">
    <PORTS>
      <PORT1>52635</PORT1>
      <PORT2>52527</PORT2>
    </PORTS>
  </PID>
  <PID pid="1313">
    <PORTS>
      <PORT1>57753</PORT1>
    </PORTS>
  </PID>
</NETSTAT>