From 7cc605964b02ba21e08ca4096bb47538192b198f Mon Sep 17 00:00:00 2001
From: Erich Eckner <git@eckner.net>
Date: Fri, 5 May 2023 21:45:50 +0200
Subject: tor-ddns.php new for handling CNAMEs to *.onion addresses

---
 tor-ddns.php | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 50 insertions(+)
 create mode 100644 tor-ddns.php

diff --git a/tor-ddns.php b/tor-ddns.php
new file mode 100644
index 0000000..33a1dd2
--- /dev/null
+++ b/tor-ddns.php
@@ -0,0 +1,50 @@
+<?php
+
+  // invalid syntax?
+  if ((!array_key_exists('i', $_GET)) ||
+      (strlen($_GET['i']) != 64) ||
+      (preg_match('@^[0-9A-Za-z]{64}$@', $_GET['i']) != 1))
+    die();
+
+  $line = preg_grep('@^' . $_GET['i'] . ' @', file('/srv/http/vhosts/eckner.net/ddns/tokens'));
+
+  // unknown token?
+  if (count($line) != 1)
+    die();
+
+  $domain = substr(explode(' ', implode('', $line))[1], 0, -1);
+  if (array_key_exists('address', $_GET))
+    $ip = $_GET['address'];
+  else
+    die();
+
+  if (preg_match('@^[0-9a-z]{56}\.onion@', $ip) != 1)
+    die();
+
+  $updateCommand = "zone ddns.eckner.net.\n";
+  $logContent = '';
+
+  // delete old record if existing
+  $updateCommand .=
+    "prereq yxrrset " . $domain . ".tor.ddns.eckner.net IN CNAME\n" .
+    "update delete " . $domain . ".tor.ddns.eckner.net IN CNAME\n" .
+    "send\n";
+
+  $updateCommand .=
+    "update add " . $domain . ".tor.ddns.eckner.net. 7200 IN CNAME " . $ip . "\n";
+  $logContent .=
+    date('Y-m-d H:i:s') . ' ' . $domain . ' ' . $ip . "\n";
+  $updateCommand .=
+    "send\n";
+
+  // actually do something
+  $pin = popen('nsupdate -l', 'w');
+  if ($pin === FALSE)
+    die_http(500, 'Internal Server Error', 'Failed to update Zone.');
+
+  fwrite($pin, $updateCommand);
+  pclose($pin);
+
+  file_put_contents('/srv/http/vhosts/eckner.net/ddns/log', $logContent, FILE_APPEND | LOCK_EX);
+
+  print "updated ips for domain \"" . $domain . ".ddns.eckner.net\": " . implode(", ", $ips) . "\n";
-- 
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