From 09cdc3782488d2e6db09baf75b0dfa1f68e5dc4f Mon Sep 17 00:00:00 2001
From: Rich Trott <rtrott@gmail.com>
Date: Tue, 16 Apr 2019 11:07:17 -0700
Subject: [PATCH] dns: do not indicate invalid IPs are IPv6

In lib/dns.js, use `isIP()` instead of `isIPv4()` for determining the
`family` property in `lookup()`. If an invalid IP address is returned,
the `family` currently provided is `6`. With this change, it will be
`0`. Update documentation to reflect this.

PR-URL: https://github.com/nodejs/node/pull/27081
Reviewed-By: Richard Lau <riclau@uk.ibm.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Ruben Bridgewater <ruben@bridgewater.de>
---
 doc/api/dns.md | 4 +++-
 lib/dns.js     | 6 +++---
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/doc/api/dns.md b/doc/api/dns.md
index d5af7aef8bfec7..22899e625c3f0b 100644
--- a/doc/api/dns.md
+++ b/doc/api/dns.md
@@ -154,7 +154,9 @@ changes:
 * `callback` {Function}
   - `err` {Error}
   - `address` {string} A string representation of an IPv4 or IPv6 address.
-  - `family` {integer} `4` or `6`, denoting the family of `address`.
+  - `family` {integer} `4` or `6`, denoting the family of `address`, or `0` if
+    the address is not an IPv4 or IPv6 address. `0` is a likely indicator of a
+    bug in the name resolution service used by the operating system.
 
 Resolves a hostname (e.g. `'nodejs.org'`) into the first found A (IPv4) or
 AAAA (IPv6) record. All `option` properties are optional. If `options` is an
diff --git a/lib/dns.js b/lib/dns.js
index b212983c4412f7..835eb91ee16b91 100644
--- a/lib/dns.js
+++ b/lib/dns.js
@@ -25,7 +25,7 @@ const { Object } = primordials;
 
 const cares = internalBinding('cares_wrap');
 const { toASCII } = require('internal/idna');
-const { isIP, isIPv4, isLegalPort } = require('internal/net');
+const { isIP, isLegalPort } = require('internal/net');
 const { customPromisifyArgs } = require('internal/util');
 const errors = require('internal/errors');
 const {
@@ -62,7 +62,7 @@ function onlookup(err, addresses) {
   if (this.family) {
     this.callback(null, addresses[0], this.family);
   } else {
-    this.callback(null, addresses[0], isIPv4(addresses[0]) ? 4 : 6);
+    this.callback(null, addresses[0], isIP(addresses[0]));
   }
 }
 
@@ -77,7 +77,7 @@ function onlookupall(err, addresses) {
     const addr = addresses[i];
     addresses[i] = {
       address: addr,
-      family: family || (isIPv4(addr) ? 4 : 6)
+      family: family || isIP(addr)
     };
   }