From 8eedfcdb5ed7378915ff05eda1263d079ba33f7d Mon Sep 17 00:00:00 2001
From: Wagner Sartori Junior <wsartori@gmail.com>
Date: Mon, 3 Feb 2020 16:56:22 +0100
Subject: [PATCH] Implement working DHCPv6 DDNS (Dynamic DNS)

Follows PR #3909 and fixes #3908
---
 src/etc/inc/plugins.inc.d/dhcpd.inc | 66 +++++++++++++++++++++--------
 src/www/services_dhcpv6.php         | 18 +++++++-
 2 files changed, 65 insertions(+), 19 deletions(-)

diff --git a/src/etc/inc/plugins.inc.d/dhcpd.inc b/src/etc/inc/plugins.inc.d/dhcpd.inc
index 628ae0088..0257ce8fa 100644
--- a/src/etc/inc/plugins.inc.d/dhcpd.inc
+++ b/src/etc/inc/plugins.inc.d/dhcpd.inc
@@ -1174,7 +1174,7 @@ EOD;
     }
 }
 
-function dhcpd_zones($ddns_zones)
+function dhcpd_zones($ddns_zones, $ipv6 = false)
 {
     $dhcpdconf = '';
 
@@ -1189,13 +1189,24 @@ function dhcpd_zones($ddns_zones)
             $primary = $zone['dns-servers'][0];
             $secondary = empty($zone['dns-servers'][1]) ? "" : $zone['dns-servers'][1];
 
-            // Make sure we aren't using any invalid or IPv6 DNS servers.
-            if (!is_ipaddrv4($primary)) {
-                if (is_ipaddrv4($secondary)) {
-                    $primary = $secondary;
-                    $secondary = "";
-                } else {
-                    continue;
+            // Make sure we aren't using any invalid DNS servers.
+            if ($ipv6) {
+                if (!is_ipaddrv6($primary)) {
+                    if (is_ipaddrv6($secondary)) {
+                        $primary = $secondary;
+                        $secondary = "";
+                    } else {
+                        continue;
+                    }
+                }
+            } else {
+                if (!is_ipaddrv4($primary)) {
+                    if (is_ipaddrv4($secondary)) {
+                        $primary = $secondary;
+                        $secondary = "";
+                    } else {
+                        continue;
+                    }
                 }
             }
 
@@ -1204,9 +1215,16 @@ function dhcpd_zones($ddns_zones)
                 if (!empty($domain) && !in_array($domain, $added_zones)) {
                     /* dhcpdconf2 is injected *after* the key */
                     $dhcpdconf2 = "zone {$domain}. {\n";
-                    $dhcpdconf2 .= "  primary {$primary};\n";
-                    if (is_ipaddrv4($secondary)) {
-                        $dhcpdconf2 .= "  secondary {$secondary};\n";
+                    if ($ipv6) {
+                        $dhcpdconf2 .= "  primary6 {$primary};\n";
+                        if (is_ipaddrv6($secondary)) {
+                            $dhcpdconf2 .= "  secondary6 {$secondary};\n";
+                        }
+                    } else {
+                        $dhcpdconf2 .= "  primary {$primary};\n";
+                        if (is_ipaddrv4($secondary)) {
+                            $dhcpdconf2 .= "  secondary {$secondary};\n";
+                        }
                     }
                     if (!empty($zone['ddnsdomainkeyname']) && !empty($zone['ddnsdomainkey'])) {
                         if (!in_array($zone['ddnsdomainkeyname'], $added_keys)) {
@@ -1407,7 +1425,7 @@ EOD;
 
     $dhcpdv6ifs = array();
     $ddns_zones = array();
-    $nsupdate = false;
+    $need_ddns_updates = false;
 
     foreach ($dhcpdv6cfg as $dhcpv6if => $dhcpv6ifconf) {
         if (!isset($dhcpv6ifconf['enable']) || !isset($iflist[$dhcpv6if])) {
@@ -1435,6 +1453,7 @@ EOD;
         $newzone = array();
 
         if (isset($dhcpv6ifconf['ddnsupdate'])) {
+            $need_ddns_updates = true;
             if (!empty($dhcpv6ifconf['ddnsdomain'])) {
                 $dnscfgv6 .= "  ddns-domainname \"{$dhcpv6ifconf['ddnsdomain']}\";\n";
                 $newzone['domain-name'] = $dhcpv6ifconf['ddnsdomain'];
@@ -1442,7 +1461,20 @@ EOD;
                 $newzone['domain-name'] = $config['system']['domain'];
             }
 
-            $nsupdate = true;
+            $subnetv6 = explode("/", $networkv6)[0];
+            $addr = inet_pton($subnetv6);
+            $addr_unpack = unpack('H*hex', $addr);
+            $addr_hex = $addr_unpack['hex'];
+            $revsubnet = array_reverse(str_split($addr_hex));
+            foreach ($revsubnet as $octet) {
+                if ($octet == "0") {
+                    array_shift($revsubnet);
+                } else {
+                    break;
+                }
+            }
+
+            $newzone['ptr-domain'] = implode(".", $revsubnet) . ".ip6.arpa";
         }
 
         if (isset($dhcpv6ifconf['dnsserver'][0])) {
@@ -1550,8 +1582,7 @@ EOD;
                 $newzone['dns-servers'] = array($dhcpv6ifconf['ddnsdomainprimary']);
                 $newzone['ddnsdomainkeyname'] = $dhcpv6ifconf['ddnsdomainkeyname'];
                 $newzone['ddnsdomainkey'] = $dhcpv6ifconf['ddnsdomainkey'];
-                /* XXX not implemented for IPv6 */
-                $newzone['ddnsdomainalgorithm'] = 'hmac-md5';
+                $newzone['ddnsdomainalgorithm'] = !empty($dhcpv6ifconf['ddnsdomainalgorithm']) ? $dhcpv6ifconf['ddnsdomainalgorithm'] : "hmac-md5";
                 $ddns_zones[] = $newzone;
             }
         }
@@ -1572,9 +1603,10 @@ EOD;
         }
     }
 
-    if ($nsupdate) {
+    if ($need_ddns_updates) {
         $dhcpdv6conf .= "\nddns-update-style interim;\n";
-        $dhcpdv6conf .= dhcpd_zones($ddns_zones);
+        $dhcpdv6conf .= "update-static-leases on;\n";
+        $dhcpdv6conf .= dhcpd_zones($ddns_zones, $ipv6 = true);
     } else {
         $dhcpdv6conf .= "\nddns-update-style none;\n";
     }
diff --git a/src/www/services_dhcpv6.php b/src/www/services_dhcpv6.php
index 89d433aa3..ee3c664fb 100644
--- a/src/www/services_dhcpv6.php
+++ b/src/www/services_dhcpv6.php
@@ -64,7 +64,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
         $pconfig['prefixrange_length'] = $config['dhcpdv6'][$if]['prefixrange']['prefixlength'];
     }
     $config_copy_fieldsnames = array('defaultleasetime', 'maxleasetime', 'domainsearchlist', 'ddnsdomain',
-        'ddnsdomainprimary', 'ddnsdomainkeyname', 'ddnsdomainkey', 'bootfile_url', 'netmask',
+        'ddnsdomainprimary', 'ddnsdomainkeyname', 'ddnsdomainkey', 'ddnsdomainalgorithm', 'bootfile_url', 'netmask',
         'numberoptions', 'dhcpv6leaseinlocaltime', 'staticmap');
     foreach ($config_copy_fieldsnames as $fieldname) {
         if (isset($config['dhcpdv6'][$if][$fieldname])) {
@@ -235,7 +235,7 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
 
             // simple 1-on-1 copy
             $config_copy_fieldsnames = array('defaultleasetime', 'maxleasetime', 'netmask', 'domainsearchlist',
-              'ddnsdomain', 'ddnsdomainprimary', 'ddnsdomainkeyname', 'ddnsdomainkey', 'bootfile_url',
+              'ddnsdomain', 'ddnsdomainprimary', 'ddnsdomainkeyname', 'ddnsdomainkey', 'ddnsdomainalgorithm', 'bootfile_url',
               'dhcpv6leaseinlocaltime');
             foreach ($config_copy_fieldsnames as $fieldname) {
                 if (!empty($pconfig[$fieldname])) {
@@ -612,6 +612,20 @@ if (isset($config['interfaces'][$if]['dhcpd6track6allowoverride'])) {
                           <input name="ddnsdomainkeyname" type="text" id="ddnsdomainkeyname" size="20" value="<?=$pconfig['ddnsdomainkeyname'];?>" />
                           <?=gettext("Enter the dynamic DNS domain key secret which will be used to register client names in the DNS server.");?>
                           <input name="ddnsdomainkey" type="text" id="ddnsdomainkey" size="20" value="<?=$pconfig['ddnsdomainkey'];?>" />
+                          <?=gettext("Choose the dynamic DNS domain key algorithm.");?><br />
+                          <select name='ddnsdomainalgorithm' id="ddnsdomainalgorithm" class="selectpicker">
+<?php
+                          foreach (array("hmac-md5", "hmac-sha512") as $algorithm) :
+                            $selected = "";
+                            if (! empty($pconfig['ddnsdomainalgorithm'])) {
+                              if ($pconfig['ddnsdomainalgorithm'] == $algorithm) {
+                                $selected = "selected=\"selected\"";
+                              }
+                            }?>
+                            <option value="<?=$algorithm;?>" <?=$selected;?>><?=$algorithm;?></option>
+<?php
+                          endforeach; ?>
+                          </select>
                         </div>
                       </td>
                     </tr>