feat(dnsserver): Return multiple matching records, improve DNSSEC RRset signing, add client resolution strategy and localhost handling, update tests

ts_server/classes.dnsserver.ts

@@ -15,6 +15,8 @@ export interface IDnsServerOptions {
   manualHttpsMode?: boolean;
   // Primary nameserver for SOA records (defaults to ns1.{dnssecZone})
   primaryNameserver?: string;
+  // Local handling for RFC 6761 localhost (default: true)
+  enableLocalhostHandling?: boolean;
 }
 
 export interface DnsAnswer {
@@ -569,6 +571,7 @@ export class DnsServer {
       console.log(`Query for ${question.name} of type ${question.type}`);
 
       let answered = false;
+      let shouldSignRrset = true; // skip DNSSEC signing for synthetic/local answers
       const recordsForQuestion: DnsAnswer[] = [];
 
       // Handle DNSKEY queries if DNSSEC is requested
@@ -582,9 +585,59 @@ export class DnsServer {
         };
         recordsForQuestion.push(dnskeyAnswer);
         answered = true;
+        // DNSKEY is signable, keep shouldSignRrset true
       } else {
+        // Built-in handling for localhost and reverse localhost (RFC 6761)
+        const enableLocal = this.options.enableLocalhostHandling !== false;
+        if (enableLocal) {
+          const qnameLower = (question.name || '').toLowerCase();
+          const qnameTrimmed = qnameLower.endsWith('.') ? qnameLower.slice(0, -1) : qnameLower;
+
+          // localhost forward lookups
+          if (qnameTrimmed === 'localhost') {
+            if (question.type === 'A') {
+              recordsForQuestion.push({
+                name: question.name,
+                type: 'A',
+                class: 'IN',
+                ttl: 0,
+                data: '127.0.0.1',
+              });
+              answered = true;
+              shouldSignRrset = false;
+            } else if (question.type === 'AAAA') {
+              recordsForQuestion.push({
+                name: question.name,
+                type: 'AAAA',
+                class: 'IN',
+                ttl: 0,
+                data: '::1',
+              });
+              answered = true;
+              shouldSignRrset = false;
+            }
+          }
+
+          // Reverse lookup for 127.0.0.1
+          if (!answered) {
+            const reverseLocalhostV4 = '1.0.0.127.in-addr.arpa';
+            if (qnameTrimmed === reverseLocalhostV4 && question.type === 'PTR') {
+              recordsForQuestion.push({
+                name: question.name,
+                type: 'PTR',
+                class: 'IN',
+                ttl: 0,
+                data: 'localhost.',
+              });
+              answered = true;
+              shouldSignRrset = false;
+            }
+          }
+        }
+
         // Collect all matching records from handlers
-        for (const handlerEntry of this.handlers) {
+        if (!answered) {
+          for (const handlerEntry of this.handlers) {
           if (
             plugins.minimatch.minimatch(question.name, handlerEntry.domainPattern) &&
             handlerEntry.recordTypes.includes(question.type)
@@ -602,6 +655,7 @@ export class DnsServer {
               // Continue processing other handlers to allow multiple records
             }
           }
+          }
         }
       }
 
@@ -612,7 +666,7 @@ export class DnsServer {
         }
         
         // Group records by type for DNSSEC signing
-        if (dnssecRequested) {
+        if (dnssecRequested && shouldSignRrset) {
           const rrsetKey = `${question.name}:${question.type}`;
           rrsetMap.set(rrsetKey, recordsForQuestion);
         }
@@ -1019,7 +1073,9 @@ export class DnsServer {
   }
 
   private nameToBuffer(name: string): Buffer {
-    const labels = name.split('.');
+    // Trim trailing dot to avoid double-root
+    const trimmed = name.endsWith('.') ? name.slice(0, -1) : name;
+    const labels = trimmed.split('.').filter(l => l.length > 0);
     const buffers = labels.map(label => {
       const len = Buffer.byteLength(label, 'utf8');
       const buf = Buffer.alloc(1 + len);
@@ -1027,6 +1083,7 @@ export class DnsServer {
       buf.write(label, 1);
       return buf;
     });
-    return Buffer.concat([...buffers, Buffer.from([0])]); // Add root label
+    // Append exactly one root label
+    return Buffer.concat([...buffers, Buffer.from([0])]);
   }
-}
+}