1 files changed, 87 insertions, 0 deletions
diff --git a/toolkit/components/extensions/parent/ext-dns.js b/toolkit/components/extensions/parent/ext-dns.js
new file mode 100644
index 0000000000..f32243c032
--- /dev/null
+++ b/toolkit/components/extensions/parent/ext-dns.js
@@ -0,0 +1,87 @@
+/* -*- Mode: indent-tabs-mode: nil; js-indent-level: 2 -*- */
+/* vim: set sts=2 sw=2 et tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+"use strict";
+
+const dnssFlags = {
+  allow_name_collisions: Ci.nsIDNSService.RESOLVE_ALLOW_NAME_COLLISION,
+  bypass_cache: Ci.nsIDNSService.RESOLVE_BYPASS_CACHE,
+  canonical_name: Ci.nsIDNSService.RESOLVE_CANONICAL_NAME,
+  disable_ipv4: Ci.nsIDNSService.RESOLVE_DISABLE_IPV4,
+  disable_ipv6: Ci.nsIDNSService.RESOLVE_DISABLE_IPV6,
+  disable_trr: Ci.nsIDNSService.RESOLVE_DISABLE_TRR,
+  offline: Ci.nsIDNSService.RESOLVE_OFFLINE,
+  priority_low: Ci.nsIDNSService.RESOLVE_PRIORITY_LOW,
+  priority_medium: Ci.nsIDNSService.RESOLVE_PRIORITY_MEDIUM,
+  speculate: Ci.nsIDNSService.RESOLVE_SPECULATE,
+};
+
+function getErrorString(nsresult) {
+  let e = new Components.Exception("", nsresult);
+  return e.name;
+}
+
+this.dns = class extends ExtensionAPI {
+  getAPI(context) {
+    return {
+      dns: {
+        resolve: function (hostname, flags) {
+          let dnsFlags = flags.reduce(
+            (mask, flag) => mask | dnssFlags[flag],
+            0
+          );
+
+          return new Promise((resolve, reject) => {
+            let request;
+            let response = {
+              addresses: [],
+            };
+            let listener = {
+              onLookupComplete: function (inRequest, inRecord, inStatus) {
+                if (inRequest === request) {
+                  if (!Components.isSuccessCode(inStatus)) {
+                    return reject({ message: getErrorString(inStatus) });
+                  }
+                  inRecord.QueryInterface(Ci.nsIDNSAddrRecord);
+                  if (dnsFlags & Ci.nsIDNSService.RESOLVE_CANONICAL_NAME) {
+                    try {
+                      response.canonicalName = inRecord.canonicalName;
+                    } catch (e) {
+                      // no canonicalName
+                    }
+                  }
+                  response.isTRR = inRecord.IsTRR();
+                  while (inRecord.hasMore()) {
+                    let addr = inRecord.getNextAddrAsString();
+                    // Sometimes there are duplicate records with the same ip.
+                    if (!response.addresses.includes(addr)) {
+                      response.addresses.push(addr);
+                    }
+                  }
+                  return resolve(response);
+                }
+              },
+            };
+            try {
+              request = Services.dns.asyncResolve(
+                hostname,
+                Ci.nsIDNSService.RESOLVE_TYPE_DEFAULT,
+                dnsFlags,
+                null, // AdditionalInfo
+                listener,
+                null,
+                {} /* defaultOriginAttributes */
+              );
+            } catch (e) {
+              // handle exceptions such as offline mode.
+              return reject({ message: e.name });
+            }
+          });
+        },
+      },
+    };
+  }
+};