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: #27081 Reviewed-By: Richard Lau <[email protected]> Reviewed-By: Luigi Pinca <[email protected]> Reviewed-By: James M Snell <[email protected]> Reviewed-By: Ruben Bridgewater <[email protected]>

Author: Trott

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

lib/dns.js

@@ -25,7 +25,7 @@ const{Object } = primordials;
 
 constcares=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');
 consterrors=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){
 constaddr=addresses[i];
 addresses[i]={
 address: addr,
-family: family||(isIPv4(addr) ? 4 : 6)
+family: family||isIP(addr)
 };
 }