JSDNS: don't treat connection error as rcode ServFail being returned

_locales/en_US/messages.json

@@ -319,7 +319,7 @@
 		"message": "DNS server $1 timed out on a TCP connection."
 	},
 	"SERVER_ERROR": {
-		"message": "Error connecting to DNS server &1."
+		"message": "Error connecting to DNS server $1."
 	},
 	"INCOMPLETE_RESPONSE": {
 		"message": "Incomplete response from $1."

_locales/es_ES/messages.json

@@ -275,7 +275,7 @@
 		"message": "El servidor DNS $1 agotó el tiempo de espera en una conexión TCP"
 	},
 	"SERVER_ERROR": {
-		"message": "Error al conectarse al servidor DNS &1"
+		"message": "Error al conectarse al servidor DNS $1"
 	},
 	"INCOMPLETE_RESPONSE": {
 		"message": "Respuesta incompleta de $1"

_locales/pt_BR/messages.json

@@ -296,7 +296,7 @@
 		"message": "O servidor DNS $1 atingiu o tempo limite em uma conexão TCP."
 	},
 	"SERVER_ERROR": {
-		"message": "Erro ao conectar ao servidor DNS &1."
+		"message": "Erro ao conectar ao servidor DNS $1."
 	},
 	"INCOMPLETE_RESPONSE": {
 		"message": "Resposta incompleta de $1."

_locales/uk/messages.json

@@ -314,7 +314,7 @@
 		"message": "Час очікування DNS-сервера $1 для TCP-з'єднання закінчився."
 	},
 	"SERVER_ERROR": {
-		"message": "Помилка підключення до DNS-сервера &1."
+		"message": "Помилка підключення до DNS-сервера $1."
 	},
 	"INCOMPLETE_RESPONSE": {
 		"message": "Неповна відповідь від $1."

experiments/JSDNS.jsm.js

@@ -694,7 +694,7 @@ function DNS_getRDData(str, server, host, recordtype, callback, callbackdata, ho
 	var rcode = flags & 0xF;
 	if (rcode !== 0) {
 		log.debug(debugstr + "Lookup failed with rcode " + rcode);
-		callback(null, callbackdata, "Lookup failed with rcode " + rcode, rcode);
+		callback(null, callbackdata, undefined, rcode);
 		return;
 	}
 

experiments/jsdns.d.ts

@@ -9,7 +9,9 @@ declare module browser {
             debug: boolean,
         ) => Promise<void>;
 
-        type TxtResult = import("../modules/dns.mjs.js").DnsTxtResult;
+        type TxtResult = import("../modules/dns.mjs.js").DnsTxtResult | {
+            error: string,
+        }
         const txt: (name: string) => Promise<TxtResult>;
     }
 }

experiments/jsdns.js

@@ -19,20 +19,6 @@
 // eslint-disable-next-line no-var
 var { Services } = ChromeUtils.import("resource://gre/modules/Services.jsm");
 
-/**
- * From https://javascriptweblog.wordpress.com/2011/08/08/fixing-the-javascript-typeof-operator/.
- *
- * @param {any} obj
- * @returns {string}
- */
-function toType(obj) {
-	const typeMatch = Object.prototype.toString.call(obj).match(/\s([a-zA-Z]+)/);
-	if (!typeMatch || !typeMatch[1]) {
-		throw new Error(`Failed to get type for ${obj}`);
-	}
-	return typeMatch[1];
-}
-
 this.jsdns = class extends ExtensionCommon.ExtensionAPI {
 	/**
 	 * @param {ExtensionCommon.Extension} extension
@@ -86,18 +72,18 @@ this.jsdns = class extends ExtensionCommon.ExtensionAPI {
 							if (rcode !== undefined) {
 								resRcode = rcode;
 							} else if (queryError !== undefined) {
-								/** @type {string|string[]} */
 								let error = "";
 								if (typeof queryError === "string") {
-									error = context.extension.localeData.localizeMessage(queryError);
-								} else if (toType(queryError) === "Array" && queryError[0]) {
-									error = context.extension.localeData.localizeMessage(queryError[0], queryError[1]);
-								}
-								if (!error) {
 									error = queryError;
+								} else {
+									error = context.extension.localeData.localizeMessage(queryError[0] ?? "DKIM_DNSERROR_UNKNOWN", queryError[1]) ||
+										(queryError[0] ?? "Unknown DNS error");
 								}
 								console.warn(`JSDNS failed with: ${error}`);
-								resRcode = RCODE.ServFail;
+								defer.resolve({
+									error,
+								});
+								return;
 							}
 
 							const results = dnsResult && dnsResult.map(rdata => {

experiments/libunbound.js

@@ -374,14 +374,6 @@ this.libunbound = class extends ExtensionCommon.ExtensionAPI {
 	 * @returns {{libunbound: browser.libunbound}}
 	 */
 	getAPI(_context) {
-		const RCODE = {
-			NoError: 0, // No Error [RFC1035]
-			FormErr: 1, // Format Error [RFC1035]
-			ServFail: 2, // Server Failure [RFC1035]
-			NXDomain: 3, // Non-Existent Domain [RFC1035]
-			NotImp: 4, // Non-Existent Domain [RFC1035]
-			Refused: 5, // Query Refused [RFC1035]
-		};
 		const libunboundWorker = this.libunboundWorker;
 		return {
 			libunbound: {
@@ -401,15 +393,6 @@ this.libunbound = class extends ExtensionCommon.ExtensionAPI {
 				},
 				async txt(name) {
 					const res = await libunboundWorker.resolve(name, LibunboundWorker.Constants.RR_TYPE_TXT);
-					if (res === null) {
-						// error in libunbound
-						return {
-							data: null,
-							rcode: RCODE.ServFail,
-							secure: false,
-							bogus: false,
-						};
-					}
 					const data = res.havedata ? res.data.map(rdata => {
 						if (typeof rdata !== "string") {
 							throw Error(`DNS result has unexpected type ${typeof rdata}`);

modules/dns.mjs.js

@@ -132,7 +132,7 @@ function configureLibunbound() {
 /**
  * Check that Thunderbird is online.
  *
- * @throws {DKIM_SigError} if Thunderbird is offline.
+ * @throws {DKIM_InternalError} if Thunderbird is offline.
  */
 function checkOnlineStatus() {
 	if (!navigator.onLine) {
@@ -157,13 +157,18 @@ export default class DNS {
 	 *
 	 * @param {string} name
 	 * @returns {Promise<DnsTxtResult>}
+	 * @throws {DKIM_InternalError} if no DNS response could be retrieved.
 	 */
 	static async txt(name) {
 		switch (prefs["dns.resolver"]) {
 			case RESOLVER_JSDNS: {
 				await configureJsdns();
 				checkOnlineStatus();
-				return browser.jsdns.txt(name);
+				const res = await browser.jsdns.txt(name);
+				if ("error" in res) {
+					throw new DKIM_InternalError(res.error, "DKIM_DNSERROR_SERVER_ERROR");
+				}
+				return res;
 			}
 			case RESOLVER_LIBUNBOUND: {
 				await configureLibunbound();