unbound: "remove" edns support

edns flag was added in 2014, but it could never be set.
Remove buffer size override along with it to further
simplify the situation.

See: https://github.com/pfsense/pfsense/commit/3b95d9e
(cherry picked from commit 493ee561)

src/etc/inc/plugins.inc.d/unbound.inc

@@ -257,7 +257,6 @@ EOF;
     $prefetch_key = !empty($config['unbound']['prefetchkey']) ? "yes" : "no";
     $outgoing_num_tcp = !empty($config['unbound']['outgoing_num_tcp']) ? $config['unbound']['outgoing_num_tcp'] : "10";
     $incoming_num_tcp = !empty($config['unbound']['incoming_num_tcp']) ? $config['unbound']['incoming_num_tcp'] : "10";
-    $edns_buffer_size = !empty($config['unbound']['edns_buffer_size']) ? $config['unbound']['edns_buffer_size'] : "4096";
     $num_queries_per_thread = !empty($config['unbound']['num_queries_per_thread']) ? $config['unbound']['num_queries_per_thread'] : "4096";
     $jostle_timeout = !empty($config['unbound']['jostle_timeout']) ? $config['unbound']['jostle_timeout'] : "200";
     $cache_max_ttl = !empty($config['unbound']['cache_max_ttl']) ? $config['unbound']['cache_max_ttl'] : "86400";
@@ -342,7 +341,6 @@ cache-min-ttl: {$cache_min_ttl}
 harden-dnssec-stripped: {$dnssecstripped}
 outgoing-num-tcp: {$outgoing_num_tcp}
 incoming-num-tcp: {$incoming_num_tcp}
-edns-buffer-size: {$edns_buffer_size}
 num-queries-per-thread: {$num_queries_per_thread}
 infra-host-ttl: {$infra_host_ttl}
 infra-cache-numhosts: {$infra_cache_numhosts}

src/etc/inc/system.inc

@@ -175,11 +175,6 @@ function system_resolvconf_generate($dynupdate = false)
         }
     }
 
-    // Add EDNS support
-    if (isset($config['unbound']['enable']) && isset($config['unbound']['edns'])) {
-        $resolvconf .= "options edns0\n";
-    }
-
     $dnslock = lock('resolvconf', LOCK_EX);
 
     file_put_contents('/etc/resolv.conf', $resolvconf);

src/www/services_unbound_advanced.php

@@ -35,9 +35,19 @@ if(empty($config['unbound']) || !is_array($config['unbound'])) {
     $config['unbound'] = array();
 }
 
-$copy_fields = array('msgcachesize', 'outgoing_num_tcp', 'incoming_num_tcp', 'edns_buffer_size',
-                    'num_queries_per_thread', 'jostle_timeout', 'cache_max_ttl', 'cache_min_ttl',
-                    'infra_host_ttl', 'infra_cache_numhosts','unwanted_reply_threshold', 'log_verbosity');
+$copy_fields = array(
+    'cache_max_ttl',
+    'cache_min_ttl',
+    'incoming_num_tcp',
+    'infra_cache_numhosts',
+    'infra_host_ttl',
+    'jostle_timeout',
+    'log_verbosity',
+    'msgcachesize',
+    'num_queries_per_thread',
+    'outgoing_num_tcp',
+    'unwanted_reply_threshold',
+);
 
 if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     $pconfig = array();
@@ -47,7 +57,6 @@ if ($_SERVER['REQUEST_METHOD'] === 'GET') {
     $pconfig['infra_host_ttl'] = 900;
     $pconfig['jostle_timeout'] = 200;
     $pconfig['infra_cache_numhosts'] = 10000;
-    $pconfig['edns_buffer_size'] = 4096;
     $pconfig['num_queries_per_thread'] = 4096;
     $pconfig['log_verbosity'] = "1";
 
@@ -217,23 +226,6 @@ include_once("head.inc");
                           </div>
                         </td>
                       </tr>
-                      <tr>
-                        <td><a id="help_for_edns_buffer_size" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?= gettext("EDNS Buffer Size") ?></td>
-                        <td>
-                          <select id="edns_buffer_size" name="edns_buffer_size" class="selectpicker">
-<?php
-                          foreach (array("512", "1480", "4096") as $size) :?>
-                            <option value="<?= $size ?>" <?= $pconfig['edns_buffer_size'] == $size ? 'selected="selected"' : '' ?>>
-                              <?= $size ?>
-                            </option>
-<?php
-                          endforeach;?>
-                          </select>
-                          <div class="hidden" for="help_for_edns_buffer_size">
-                            <?= gettext("Number of bytes size to advertise as the EDNS reassembly buffer size. This is the value that is used in UDP datagrams sent to peers. RFC recommendation is 4096 (which is the default). If you have fragmentation reassemble problems, usually seen as timeouts, then a value of 1480 should help. The 512 value bypasses most MTU path problems, but it can generate an excessive amount of TCP fallback.") ?>
-                          </div>
-                        </td>
-                      </tr>
                       <tr>
                         <td><a id="help_for_num_queries_per_thread" href="#" class="showhelp"><i class="fa fa-info-circle"></i></a> <?=gettext("Number of queries per thread");?></td>
                         <td>