From e9c37a44c8bf93d53766303ff10997829efe92a9 Mon Sep 17 00:00:00 2001
From: Tomas Mudrunka <tomas@mudrunka.cz>
Date: Thu, 8 Oct 2020 09:37:28 +0200
Subject: [PATCH] Spravne zarovnani delek ipv6 adres reverzu

---
 php/ipv6wildcard.php | 26 ++++++++++++++++++++------
 1 file changed, 20 insertions(+), 6 deletions(-)

diff --git a/php/ipv6wildcard.php b/php/ipv6wildcard.php
index 289c0fd..458b3b3 100755
--- a/php/ipv6wildcard.php
+++ b/php/ipv6wildcard.php
@@ -8,6 +8,8 @@
  * addresses to be used for as reverse DNS records
  */
 function ipv6_prefix2wildcards($address, $prefix) {
+	//Special case of /0 prefix
+	if($prefix == 0) return ['*'];
 
 	//Parse ip and prefix
 	echo("IPv6 prefix: ".$address."/".$prefix."\n");
@@ -16,9 +18,10 @@ function ipv6_prefix2wildcards($address, $prefix) {
 	$a = gmp_import($addr);
 
 	//Separate maskable octets
-	$pref_hex = ceil($pref / 4)*4; //Prefix rounded up to full octets
-	$pref_rem = $pref_hex - $pref; //Remainder of prefix
-	echo("Rounding prefix: ".$pref_hex."-".$pref_rem."\n");
+	$pref_hex = ceil($pref / 4); //Number of prefix octets
+	$pref_bin = $pref_hex*4; //Number of prefix octets in bits
+	$pref_rem = $pref_bin - $pref; //Remainder of prefix
+	echo("Rounding prefix: ".$pref_bin."-".$pref_rem."\n");
 
 	$a = gmp_div_q($a, gmp_pow(2,128-$prefix)); //Truncate to just prefix
 	$a = gmp_mul($a, gmp_pow(2,$pref_rem)); //Fill remaining bits in last wildcard octet with zeros
@@ -28,12 +31,19 @@ function ipv6_prefix2wildcards($address, $prefix) {
 	for($i = 0; $i < (2**$pref_rem) ; $i++) {
 		//echo("ADDED: ".$i." = ".decbin($i)."\n");
 		$ap = gmp_or($a, gmp_init($i));
-		$wildcards[] = $ap;
+		$w = gmp_strval($ap, 16);
+		$w = str_repeat('0', $pref_hex-strlen($w)).$w;
+		if(strlen($w) < 32) $w.='*';
+		$wildcards[] = $w;
 	}
 
 	return $wildcards;
 }
 
+function ipv6_string2rev($str) {
+	return implode('.',str_split(strrev($str)));
+}
+
 if(isset($argv[2])) {
 	$wcs = ipv6_prefix2wildcards($argv[1],$argv[2]);
 } else {
@@ -42,6 +52,10 @@ if(isset($argv[2])) {
 
 echo("\n");
 foreach($wcs as $w) {
-  //echo(gmp_strval($w, 2)."* :-)\n");
-  echo(gmp_strval($w, 16)."*\n");
+	echo($w."\n");
+}
+
+echo("\n");
+foreach($wcs as $w) {
+	echo(ipv6_string2rev($w)."\n");
 }
-- 
2.30.2