net,dgram: add ipv6Only option for net and dgram

For TCP servers, the dual-stack support is enable by default, i.e.
binding host "::" will also make "0.0.0.0" bound. This commit add
ipv6Only option in `net.Server.listen()` and `dgram.createSocket()`
methods which allows to disable dual-stack support. Support for
cluster module is also provided in this commit.

Fixes: https://github.com/nodejs/node/issues/17664

PR-URL: https://github.com/nodejs/node/pull/23798
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>
Reviewed-By: James M Snell <jasnell@gmail.com>

1 files changed, 20 insertions, 15 deletions

diff --git a/lib/net.js b/lib/net.js
index 01cfed98e8..25767b2574 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -97,6 +97,10 @@ const {
 
 function noop() {}
 
+function getFlags(ipv6Only) {
+  return ipv6Only === true ? TCPConstants.UV_TCP_IPV6ONLY : 0;
+}
+
 function createHandle(fd, is_server) {
   validateInt32(fd, 'fd', 0);
   const type = TTYWrap.guessHandleType(fd);
@@ -798,7 +802,7 @@ function checkBindError(err, port, handle) {
 
 
 function internalConnect(
-  self, address, port, addressType, localAddress, localPort) {
+  self, address, port, addressType, localAddress, localPort, flags) {
   // TODO return promise from Socket.prototype.connect which
   // wraps _connectReq.
 
@@ -812,7 +816,7 @@ function internalConnect(
       err = self._handle.bind(localAddress, localPort);
     } else { // addressType === 6
       localAddress = localAddress || '::';
-      err = self._handle.bind6(localAddress, localPort);
+      err = self._handle.bind6(localAddress, localPort, flags);
     }
     debug('binding to localAddress: %s and localPort: %d (addressType: %d)',
           localAddress, localPort, addressType);
@@ -1148,7 +1152,7 @@ util.inherits(Server, EventEmitter);
 function toNumber(x) { return (x = Number(x)) >= 0 ? x : false; }
 
 // Returns handle if it can be created, or error code if it can't
-function createServerHandle(address, port, addressType, fd) {
+function createServerHandle(address, port, addressType, fd, flags) {
   var err = 0;
   // assign handle in listen, and clean up if bind or listen fails
   var handle;
@@ -1187,14 +1191,14 @@ function createServerHandle(address, port, addressType, fd) {
     debug('bind to', address || 'any');
     if (!address) {
       // Try binding to ipv6 first
-      err = handle.bind6('::', port);
+      err = handle.bind6('::', port, flags);
       if (err) {
         handle.close();
         // Fallback to ipv4
         return createServerHandle('0.0.0.0', port);
       }
     } else if (addressType === 6) {
-      err = handle.bind6(address, port);
+      err = handle.bind6(address, port, flags);
     } else {
       err = handle.bind(address, port);
     }
@@ -1208,7 +1212,7 @@ function createServerHandle(address, port, addressType, fd) {
   return handle;
 }
 
-function setupListenHandle(address, port, addressType, backlog, fd) {
+function setupListenHandle(address, port, addressType, backlog, fd, flags) {
   debug('setupListenHandle', address, port, addressType, backlog, fd);
 
   // If there is not yet a handle, we need to create one and bind.
@@ -1222,7 +1226,7 @@ function setupListenHandle(address, port, addressType, backlog, fd) {
 
     // Try to bind to the unspecified IPv6 address, see if IPv6 is available
     if (!address && typeof fd !== 'number') {
-      rval = createServerHandle('::', port, 6, fd);
+      rval = createServerHandle('::', port, 6, fd, flags);
 
       if (typeof rval === 'number') {
         rval = null;
@@ -1235,7 +1239,7 @@ function setupListenHandle(address, port, addressType, backlog, fd) {
     }
 
     if (rval === null)
-      rval = createServerHandle(address, port, addressType, fd);
+      rval = createServerHandle(address, port, addressType, fd, flags);
 
     if (typeof rval === 'number') {
       var error = uvExceptionWithHostPort(rval, 'listen', address, port);
@@ -1294,7 +1298,7 @@ function emitListeningNT(self) {
 
 
 function listenInCluster(server, address, port, addressType,
-                         backlog, fd, exclusive) {
+                         backlog, fd, exclusive, flags) {
   exclusive = !!exclusive;
 
   if (cluster === undefined) cluster = require('cluster');
@@ -1303,7 +1307,7 @@ function listenInCluster(server, address, port, addressType,
     // Will create a new handle
     // _listen2 sets up the listened handle, it is still named like this
     // to avoid breaking code that wraps this method
-    server._listen2(address, port, addressType, backlog, fd);
+    server._listen2(address, port, addressType, backlog, fd, flags);
     return;
   }
 
@@ -1312,7 +1316,7 @@ function listenInCluster(server, address, port, addressType,
     port: port,
     addressType: addressType,
     fd: fd,
-    flags: 0
+    flags,
   };
 
   // Get the master's server handle, and listen on it
@@ -1330,7 +1334,7 @@ function listenInCluster(server, address, port, addressType,
     server._handle = handle;
     // _listen2 sets up the listened handle, it is still named like this
     // to avoid breaking code that wraps this method
-    server._listen2(address, port, addressType, backlog, fd);
+    server._listen2(address, port, addressType, backlog, fd, flags);
   }
 }
 
@@ -1353,6 +1357,7 @@ Server.prototype.listen = function(...args) {
     toNumber(args.length > 2 && args[2]);  // (port, host, backlog)
 
   options = options._handle || options.handle || options;
+  const flags = getFlags(options.ipv6Only);
   // (handle[, backlog][, cb]) where handle is an object with a handle
   if (options instanceof TCP) {
     this._handle = options;
@@ -1387,7 +1392,7 @@ Server.prototype.listen = function(...args) {
     // start TCP server listening on host:port
     if (options.host) {
       lookupAndListen(this, options.port | 0, options.host, backlog,
-                      options.exclusive);
+                      options.exclusive, flags);
     } else { // Undefined host, listens on unspecified address
       // Default addressType 4 will be used to search for master server
       listenInCluster(this, null, options.port | 0, 4,
@@ -1434,7 +1439,7 @@ Server.prototype.listen = function(...args) {
   throw new ERR_INVALID_OPT_VALUE('options', util.inspect(options));
 };
 
-function lookupAndListen(self, port, address, backlog, exclusive) {
+function lookupAndListen(self, port, address, backlog, exclusive, flags) {
   if (dns === undefined) dns = require('dns');
   dns.lookup(address, function doListen(err, ip, addressType) {
     if (err) {
@@ -1442,7 +1447,7 @@ function lookupAndListen(self, port, address, backlog, exclusive) {
     } else {
       addressType = ip ? addressType : 4;
       listenInCluster(self, ip, port, addressType,
-                      backlog, undefined, exclusive);
+                      backlog, undefined, exclusive, flags);
     }
   });
 }