dns: support AbortSignal in dns.lookup() and dns.promises.lookup()

doc/api/dns.md

@@ -274,6 +274,9 @@ changes:
     **Default:** `true` (addresses are not reordered). Default value is
     configurable using [`dns.setDefaultResultOrder()`][] or
     [`--dns-result-order`][].
+  * `signal` {AbortSignal} An AbortSignal that may be used to cancel an
+    in-progress lookup. If the signal is aborted, the callback is called with
+    an `AbortError`.
 * `callback` {Function}
   * `err` {Error}
   * `address` {string} A string representation of an IPv4 or IPv6 address.
@@ -1125,6 +1128,9 @@ changes:
     expected to change in the not too distant future. Default value is
     configurable using [`dns.setDefaultResultOrder()`][] or
     [`--dns-result-order`][].
+  * `signal` {AbortSignal} An AbortSignal that may be used to cancel an
+    in-progress lookup. If the signal is aborted, the returned `Promise` is
+    rejected with an `AbortError`.
 
 Resolves a host name (e.g. `'nodejs.org'`) into the first found A (IPv4) or
 AAAA (IPv6) record. All `option` properties are optional. If `options` is an

lib/dns.js

@@ -31,6 +31,7 @@
 const { isIP } = require('internal/net');
 const { customPromisifyArgs } = require('internal/util');
 const {
+  AbortError,
   DNSException,
   codes: {
     ERR_INVALID_ARG_TYPE,
@@ -78,6 +79,7 @@
   CANCELLED,
 } = dnsErrorCodes;
 const {
+  validateAbortSignal,
   validateBoolean,
   validateFunction,
   validateNumber,
@@ -86,6 +88,8 @@
   validateString,
 } = require('internal/validators');
 
+let kResistStopPropagation;
+
 const {
   GetAddrInfoReqWrap,
   GetNameInfoReqWrap,
@@ -106,6 +110,7 @@
 let promises = null; // Lazy loaded
 
 function onlookup(err, addresses) {
+  if (this.aborted) return;
   if (err) {
     return this.callback(new DNSException(err, 'getaddrinfo', this.hostname));
   }
@@ -117,6 +122,7 @@
 
 
 function onlookupall(err, addresses) {
+  if (this.aborted) return;
   if (err) {
     return this.callback(new DNSException(err, 'getaddrinfo', this.hostname));
   }
@@ -143,6 +149,7 @@
   let hints = 0;
   let family = 0;
   let all = false;
+  let signal;
   let dnsOrder = getDefaultResultOrder();
 
   // Parse arguments
@@ -195,6 +202,15 @@
       validateOneOf(options.order, 'options.order', validDnsOrders);
       dnsOrder = options.order;
     }
+    if (options?.signal != null) {
+      validateAbortSignal(options.signal, 'options.signal');
+    }
+    signal = options?.signal;
+  }
+
+  if (signal?.aborted) {
+    process.nextTick(callback, new AbortError(undefined, { cause: signal.reason }));
+    return {};
   }
 
   if (!hostname) {
@@ -234,6 +250,23 @@
     process.nextTick(callback, new DNSException(err, 'getaddrinfo', hostname));
     return {};
   }
+  if (signal) {
+    const onAbort = () => {
+      req.aborted = true;
+      req.callback(new AbortError(undefined, { cause: signal.reason }));
+    };
+    kResistStopPropagation ??= require('internal/event_target').kResistStopPropagation;
+    signal.addEventListener('abort', onAbort, {
+      __proto__: null,
+      once: true,
+      [kResistStopPropagation]: true,
+    });
+    const originalOncomplete = req.oncomplete;
+    req.oncomplete = function(...args) {
+      signal.removeEventListener('abort', onAbort);
+      return originalOncomplete.apply(this, args);
+    };
+  }
   if (hasObserver('dns')) {
     const detail = {
       hostname,

lib/internal/dns/promises.js

@@ -4,6 +4,7 @@
   FunctionPrototypeCall,
   ObjectDefineProperty,
   Promise,
+  SafePromisePrototypeFinally,
   Symbol,
 } = primordials;
 
@@ -46,6 +47,7 @@
   CANCELLED,
 } = dnsErrorCodes;
 const {
+  AbortError,
   DNSException,
   codes: {
     ERR_INVALID_ARG_TYPE,
@@ -65,13 +67,16 @@
   DNS_ORDER_IPV6_FIRST,
 } = internalBinding('cares_wrap');
 const {
+  validateAbortSignal,
   validateBoolean,
   validateNumber,
   validateOneOf,
   validatePort,
   validateString,
 } = require('internal/validators');
 
+let kResistStopPropagation;
+
 const kPerfHooksDnsLookupContext = Symbol('kPerfHooksDnsLookupContext');
 const kPerfHooksDnsLookupServiceContext = Symbol('kPerfHooksDnsLookupServiceContext');
 const kPerfHooksDnsLookupResolveContext = Symbol('kPerfHooksDnsLookupResolveContext');
@@ -83,6 +88,7 @@
 } = require('internal/perf/observe');
 
 function onlookup(err, addresses) {
+  if (this.aborted) return;
   if (err) {
     this.reject(new DNSException(err, 'getaddrinfo', this.hostname));
     return;
@@ -96,6 +102,7 @@
 }
 
 function onlookupall(err, addresses) {
+  if (this.aborted) return;
   if (err) {
     this.reject(new DNSException(err, 'getaddrinfo', this.hostname));
     return;
@@ -131,8 +138,13 @@
  * @property {string} address - The IP address.
  * @property {0 | 4 | 6} family - The IP address type. 4 for IPv4 or 6 for IPv6, or 0 (for both).
  */
-function createLookupPromise(family, hostname, all, hints, dnsOrder) {
-  return new Promise((resolve, reject) => {
+function createLookupPromise(family, hostname, all, hints, dnsOrder, signal) {
+  if (signal?.aborted) {
+    return Promise.reject(new AbortError(undefined, { cause: signal.reason }));
+  }
+
+  let onabort;
+  const promise = new Promise((resolve, reject) => {
     if (!hostname) {
       reject(new ERR_INVALID_ARG_VALUE('hostname', hostname,
                                        'must be a non-empty string'));
@@ -167,17 +179,36 @@
 
     if (err) {
       reject(new DNSException(err, 'getaddrinfo', hostname));
-    } else if (hasObserver('dns')) {
-      const detail = {
-        hostname,
-        family,
-        hints,
-        verbatim: order === DNS_ORDER_VERBATIM,
-        order: dnsOrder,
-      };
-      startPerf(req, kPerfHooksDnsLookupContext, { type: 'dns', name: 'lookup', detail });
+    } else {
+      if (signal) {
+        onabort = () => {
+          req.aborted = true;
+          reject(new AbortError(undefined, { cause: signal.reason }));
+        };
+        kResistStopPropagation ??= require('internal/event_target').kResistStopPropagation;
+        signal.addEventListener('abort', onabort, {
+          __proto__: null,
+          once: true,
+          [kResistStopPropagation]: true,
+        });
+      }
+      if (hasObserver('dns')) {
+        const detail = {
+          hostname,
+          family,
+          hints,
+          verbatim: order === DNS_ORDER_VERBATIM,
+          order: dnsOrder,
+        };
+        startPerf(req, kPerfHooksDnsLookupContext, { type: 'dns', name: 'lookup', detail });
+      }
     }
   });
+
+  return onabort !== undefined ?
+    SafePromisePrototypeFinally(
+      promise,
+      () => signal.removeEventListener('abort', onabort)) : promise;
 }
 
 /**
@@ -196,6 +227,7 @@
   let hints = 0;
   let family = 0;
   let all = false;
+  let signal;
   let dnsOrder = getDefaultResultOrder();
 
   // Parse arguments
@@ -230,9 +262,13 @@
       validateOneOf(options.order, 'options.order', validDnsOrders);
       dnsOrder = options.order;
     }
+    if (options?.signal != null) {
+      validateAbortSignal(options.signal, 'options.signal');
+    }
+    signal = options?.signal;
   }
 
-  return createLookupPromise(family, hostname, all, hints, dnsOrder);
+  return createLookupPromise(family, hostname, all, hints, dnsOrder, signal);
 }