GCS: Add backend for usagetracker.

Collect statistics about the usage of our software and hardware
     to enable us to make things better for you.

ground/usagetracker/backend/usagetracker.php

@@ -0,0 +1,81 @@
+<?php
+
+if (!$_SERVER['REQUEST_METHOD'] === 'GET' || empty($_GET['hash']))  {
+    usage_error();
+}
+
+// NOTE: $hash not sanitized because of the checksum match test.
+$hash = $_GET['hash'];
+$string = str_replace('&hash=' . $hash, '', rawurldecode($_SERVER['QUERY_STRING']));
+
+if ($hash != md5($string)) {
+    usage_error();
+}
+
+
+$dbhost   = 'localhost';
+$dbname   = '';
+$dbpasswd = '';
+$dbuser   = '';
+
+$db = new mysqli($dbhost, $dbuser, $dbpasswd, $dbname);
+unset($dbhost, $dbuser, $dbpasswd, $dbname);
+
+if ($db->connect_error) {
+    die();
+}
+
+$sql = sprintf("SELECT id, last_date FROM usagetracker WHERE hash = '%s' LIMIT 1", 
+    $db->real_escape_string($hash)
+);
+
+$res = $db->query($sql);
+if ($res->num_rows > 0) {
+    // Shouldn't normally be here but happens if GCS settings are reset
+    // or if the request come from another source than GCS.
+
+    $hashUpdate = $res->fetch_assoc();
+    if ($hashUpdate['last_date'] < (time() - 3600)) {
+        // Update timestamp and connection count.
+        $sql = sprintf("UPDATE usagetracker SET last_date = %u, count = count + 1 WHERE id = %u LIMIT 1",
+            time(),
+            $hashUpdate['id']
+        );
+        $db->query($sql);
+    }
+}
+else {
+    // New hash
+    $sql = sprintf("INSERT INTO usagetracker (first_date, last_date, ip, data, hash)
+                         VALUES (%u, %u, '%s', '%s', '%s')",
+        time(),
+        time(),
+        encode_ip($_SERVER['REMOTE_ADDR']),
+        $db->real_escape_string($string),
+        $db->real_escape_string($_GET['hash'])
+    );
+
+    $db->query($sql);
+}
+
+$db->close();
+
+
+function usage_error()
+{
+    //ob_start();
+
+    header($_SERVER["SERVER_PROTOCOL"]." 404 Not Found");
+    header("Status: 404 Not Found");
+
+    // Matching server 404 output can be added.
+    exit();
+}
+
+function encode_ip($dotquad_ip)
+{
+    $ip_sep = explode('.', $dotquad_ip);
+    return sprintf('%02x%02x%02x%02x', $ip_sep[0], $ip_sep[1], $ip_sep[2], $ip_sep[3]);
+}
+
+?>

ground/usagetracker/backend/usagetracker.sql

@@ -0,0 +1,62 @@
+-- phpMyAdmin SQL Dump
+-- version 4.4.14.1
+-- http://www.phpmyadmin.net
+--
+-- Host: localhost
+-- Generation Time: Sep 13, 2015 at 03:06 PM
+-- Server version: 10.0.20-MariaDB
+-- PHP Version: 5.6.13
+
+SET SQL_MODE = "NO_AUTO_VALUE_ON_ZERO";
+SET time_zone = "+00:00";
+
+
+/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
+/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
+/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
+/*!40101 SET NAMES utf8mb4 */;
+
+--
+-- Database: `usagetracker`
+--
+
+-- --------------------------------------------------------
+
+--
+-- Table structure for table `usagetracker`
+--
+
+CREATE TABLE IF NOT EXISTS `usagetracker` (
+  `id` int(11) unsigned NOT NULL,
+  `first_date` int(11) unsigned NOT NULL,
+  `last_date` int(11) unsigned NOT NULL,
+  `ip` varchar(8) COLLATE utf8_bin NOT NULL,
+  `count` smallint(4) unsigned NOT NULL DEFAULT '1',
+  `data` varchar(2000) COLLATE utf8_bin NOT NULL,
+  `hash` varchar(32) COLLATE utf8_bin NOT NULL
+) ENGINE=InnoDB DEFAULT CHARSET=utf8 COLLATE=utf8_bin;
+
+--
+-- Indexes for dumped tables
+--
+
+--
+-- Indexes for table `usagetracker`
+--
+ALTER TABLE `usagetracker`
+  ADD PRIMARY KEY (`id`),
+  ADD KEY `last_date` (`last_date`),
+  ADD KEY `hash` (`hash`);
+
+--
+-- AUTO_INCREMENT for dumped tables
+--
+
+--
+-- AUTO_INCREMENT for table `usagetracker`
+--
+ALTER TABLE `usagetracker`
+  MODIFY `id` int(11) unsigned NOT NULL AUTO_INCREMENT;
+/*!40101 SET CHARACTER_SET_CLIENT=@OLD_CHARACTER_SET_CLIENT */;
+/*!40101 SET CHARACTER_SET_RESULTS=@OLD_CHARACTER_SET_RESULTS */;
+/*!40101 SET COLLATION_CONNECTION=@OLD_COLLATION_CONNECTION */;