Help With PayPal IPN

Hello,
I have a page ipn.php

<?php
//include database connection file
include("db.php");

// read the post from PayPal system and add 'cmd'
$req = 'cmd=_notify-validate';

foreach ($_POST as $key => $value) {
  $value = urlencode(stripslashes($value));
  $req .= "&$key=$value";
}

// post back to PayPal system to validate
$header .= "POST /cgi-bin/webscr HTTP/1.0\r\n";
$header .= "Content-Type: application/x-www-form-urlencoded\r\n";
$header .= 'Content-Length: ' . strlen($req) . "\r\n\r\n";
$fp = fsockopen ('www.paypal.com', 80, $errno, $errstr, 30);


// assign posted variables to local variables
// note: additional IPN variables also available -- see IPN documentation
$item_name = $_POST['item_name'];
$receiver_email = $_POST['receiver_email'];
$item_number = $_POST['item_number'];
$invoice = $_POST['invoice'];
$payment_status = $_POST['payment_status'];
$payment_gross = $_POST['payment_gross'];
$txn_id = $_POST['txn_id'];
$pp_email = $_POST['payer_email'];


if (!$fp) {
    $req .="&ERROR";
  // ERROR
  echo "$errstr ($errno)";
} else {
  fputs ($fp, $header . $req);
  while (!feof($fp)) {
    $res = fgets ($fp, 1024);
    if (strcmp ($res, "VERIFIED") == 0) {
                $req .="&FAILED";
        echo "<pre>";
        print_r($_POST);
        if($_POST[payment_status]=="Completed") {


// update accounts and logs here
@mysql_query("UPDATE members SET money = money+".$payment_gross." WHERE paypal_email = '".$pp_email."'");
@mysql_query("UPDATE members SET paypal = paypal+".$payment_gross." WHERE paypal_email = '".$pp_email."'");

        }

      // check the payment_status is Completed
      // check that txn_id has not been previously processed
      // check that receiver_email is an email address in your PayPal account
      // process payment
      }
      else if (strcmp ($res, "INVALID") == 0) {
        $req .="&FAILURE";
                // log for manual investigation
      }
  }
  fclose ($fp);
}
?>

PHP:

ipn.php is the file paypal needs

but on http://example.com/account/add-funds/paypal/ i have a page where the user will make a request to add money to his account.

I need help on what code should be on http://example.com/account/add-funds/paypal/

Please Help,
This is giving me a headache
Chris
</div>

 

<form name="_xclick" target="paypal" action="https://www.sandbox.paypal.com/cgi-bin/webscr" method="post">
<input type="hidden" name="cmd" value="_cart">
<input type="hidden" name="business" value="my.paypal@example.com">
<input type="hidden" name="currency_code" value="USD">
<input type="hidden" name="item_name" value="Item Name">
<input type="hidden" name="amount" value="1.00">
<input type="image" src="http://www.paypal.com/en_US/i/btn/sc-but-01.gif" border="0" name="submit" alt="Make payments with PayPal - it's fast, free and secure!">
<input type="hidden" name="add" value="1">
<input type="hidden" name="custom" value="AnyIdentifierSayUsername">
<input type="hidden" name="return" value="http://www.example.com/thanks.php">
<input type="hidden" name="cancel_return" value="http://www.example.com/failed.php">
<input type="hidden" name="notify_url" value="http://www.example.com/ipn.php">
</form>

Code (markup):

Use the identifier you pass in custom field to collect back and process the IPN recieved. Change values as needed. Hope this helps