From b21b5f1e246029589c66e2aee6f9debd3cd36776 Mon Sep 17 00:00:00 2001
From: Guy Bedford <guybedford@gmail.com>
Date: Mon, 27 Jul 2026 12:39:30 -0700
Subject: [PATCH] net: support sending net.BoundSocket to threads and child
 processes

This adds support for transferring net.BoundSocket instances to other
threads via the worker_threads postMessage() transfer list, and for
sending them to child processes as the sendHandle argument of
subprocess.send(), following on from the BoundSocket introduction.

A BoundSocket reserves a port synchronously at construction time.
Making it transferable means a port can be reserved on one thread or
process and the bound (but not yet listening or connected) TCP handle
handed off to another to listen or connect on, without racing on the
bind.

For threads, BoundSocket implements kTransfer/kTransferList/
kDeserialize, moving the underlying TCP handle with the same mechanism
used for net.Socket and net.Server transfer. For child processes, the
handleConversion entry reuses the same transfer protocol on the
sending side and the same _TransferredBoundSocket deserialization path
on the receiving side; the underlying transport is that of cluster's
shared-handle scheduling: SCM_RIGHTS on Unix and WSADuplicateSocket on
Windows, both of which carry bind state.

In both cases the source instance is left in the adopted state:
address(), fd() and close() throw ERR_SOCKET_HANDLE_ADOPTED. Transfer
requires an un-adopted, open TCP handle, otherwise
ERR_WORKER_HANDLE_NOT_TRANSFERABLE is thrown; pipe (path) binds are
not transferable and throw ERR_INVALID_HANDLE_TYPE when sent over IPC.
On the receiving side the local address is re-derived from the handle
rather than trusted from serialized state.

Signed-off-by: Guy Bedford <guybedford@gmail.com>
---
 doc/api/child_process.md                      | 16 +++-
 doc/api/errors.md                             | 12 +--
 doc/api/net.md                                | 15 ++++
 doc/api/worker_threads.md                     |  4 +-
 lib/internal/child_process.js                 | 65 +++++++++++----
 lib/net.js                                    | 65 ++++++++++++++-
 .../test-child-process-send-boundsocket.js    | 79 +++++++++++++++++++
 .../test-net-boundsocket-transfer-worker.js   | 64 +++++++++++++++
 test/parallel/test-net-transfer-guards.js     | 39 ++++++++-
 9 files changed, 329 insertions(+), 30 deletions(-)
 create mode 100644 test/parallel/test-child-process-send-boundsocket.js
 create mode 100644 test/parallel/test-net-boundsocket-transfer-worker.js

diff --git a/doc/api/child_process.md b/doc/api/child_process.md
index e90759b16d3fa8..49dee96d5e90a8 100644
--- a/doc/api/child_process.md
+++ b/doc/api/child_process.md
@@ -1552,7 +1552,7 @@ added: v0.5.9
 
 * `message` {Object} A parsed JSON object or primitive value.
 * `sendHandle` {Handle|undefined} `undefined` or a [`net.Socket`][],
-  [`net.Server`][], or [`dgram.Socket`][] object.
+  [`net.Server`][], [`net.BoundSocket`][], or [`dgram.Socket`][] object.
 
 The `'message'` event is triggered when a child process uses
 [`process.send()`][] to send messages.
@@ -1858,6 +1858,9 @@ subprocess.ref();
 <!-- YAML
 added: v0.5.9
 changes:
+  - version: REPLACEME
+    pr-url: https://github.com/nodejs/node/pull/64725
+    description: '`net.BoundSocket` instances can now be sent.'
   - version: v5.8.0
     pr-url: https://github.com/nodejs/node/pull/5283
     description: The `options` parameter, and the `keepOpen` option
@@ -1872,7 +1875,7 @@ changes:
 
 * `message` {Object}
 * `sendHandle` {Handle|undefined} `undefined`, or a [`net.Socket`][],
-  [`net.Server`][], or [`dgram.Socket`][] object.
+  [`net.Server`][], [`net.BoundSocket`][], or [`dgram.Socket`][] object.
 * `options` {Object} The `options` argument, if present, is an object used to
   parameterize the sending of certain types of handles. `options` supports
   the following properties:
@@ -1939,12 +1942,18 @@ Applications should avoid using such messages or listening for
 `'internalMessage'` events as it is subject to change without notice.
 
 The optional `sendHandle` argument that may be passed to `subprocess.send()` is
-for passing a TCP server or socket object to the child process. The child process will
+for passing a TCP server, socket or [`net.BoundSocket`][] object to the child
+process. The child process will
 receive the object as the second argument passed to the callback function
 registered on the [`'message'`][] event. Any data that is received
 and buffered in the socket will not be sent to the child. Sending IPC sockets is
 not supported on Windows.
 
+Sending a `net.BoundSocket` moves its underlying TCP handle to the child
+process, leaving the source instance in the adopted state as if it had been
+adopted by a server or socket. The bound socket must not have been adopted or
+closed, and pipe (`path`) binds cannot be sent.
+
 The optional `callback` is a function that is invoked after the message is
 sent but before the child process may have received it. The function is called with a
 single argument: `null` on success, or an [`Error`][] object on failure.
@@ -2372,6 +2381,7 @@ or [`child_process.fork()`][].
 [`child_process.spawnSync()`]: #child_processspawnsynccommand-args-options
 [`dgram.Socket`]: dgram.md#class-dgramsocket
 [`maxBuffer` and Unicode]: #maxbuffer-and-unicode
+[`net.BoundSocket`]: net.md#class-netboundsocket
 [`net.Server`]: net.md#class-netserver
 [`net.Socket`]: net.md#class-netsocket
 [`options.detached`]: #optionsdetached
diff --git a/doc/api/errors.md b/doc/api/errors.md
index a7a7e6549f68e6..ae8e929dc25bbc 100644
--- a/doc/api/errors.md
+++ b/doc/api/errors.md
@@ -3004,8 +3004,9 @@ A call was made and the UDP subsystem was not running.
 ### `ERR_SOCKET_HANDLE_ADOPTED`
 
 An operation was attempted on a [`BoundSocket`][] that had already been adopted
-by a [`net.Server`][] or [`net.Socket`][]. Once a bound socket is adopted, its
-`address()` and `close()` methods can no longer be used.
+by a [`net.Server`][] or [`net.Socket`][], or transferred to another thread.
+Once a bound socket is adopted or transferred, its `address()` and `close()`
+methods can no longer be used.
 
 <a id="ERR_SOURCE_MAP_CORRUPT"></a>
 
@@ -3573,9 +3574,10 @@ The `Response` that has been passed to `WebAssembly.compileStreaming` or to
 
 ### `ERR_WORKER_HANDLE_NOT_TRANSFERABLE`
 
-An attempt was made to transfer a `net.Socket` or `net.Server` to another thread
-via a `worker_threads` `postMessage()` call while it was not in a transferable
-state, for example because it had already started reading or had buffered data.
+An attempt was made to transfer a `net.Socket`, `net.Server` or
+`net.BoundSocket` to another thread via a `worker_threads` `postMessage()` call
+while it was not in a transferable state, for example because it had already
+started reading, had buffered data, or had already been adopted.
 
 <a id="ERR_WORKER_INIT_FAILED"></a>
 
diff --git a/doc/api/net.md b/doc/api/net.md
index 988bc5669e7ff9..c5f041f38fb7e1 100644
--- a/doc/api/net.md
+++ b/doc/api/net.md
@@ -789,6 +789,13 @@ server.listen(8000);
 A listening [`net.Server`][] can be transferred the same way, which moves the
 listening socket itself (and its pending accept queue) to the receiving thread.
 
+An un-adopted TCP [`BoundSocket`][] can also be transferred, which moves the
+bound (but not yet listening or connected) socket. This allows a port to be
+reserved synchronously on one thread and adopted by a server or outgoing
+connection on another. Pipe binds are not transferable. After the transfer, the
+source `BoundSocket` behaves as if it had been adopted: `address()`, `fd()` and
+`close()` throw [`ERR_SOCKET_HANDLE_ADOPTED`][].
+
 ### `new net.Socket([options])`
 
 <!-- YAML
@@ -1718,6 +1725,13 @@ file system entry; abstract and TCP binds have none to remove.
 When a pipe `BoundSocket` bound to a source `path` is adopted as a client, that
 path is reported as the socket's `localAddress` once it connects.
 
+An un-adopted TCP `BoundSocket` can be moved to another thread by listing it in
+the `transferList` of a [`worker_threads`][] `postMessage()` call, see
+[Transferring TCP handles to other threads][]. It can likewise be sent to a
+child process as the `sendHandle` argument of [`subprocess.send()`][]. In both
+cases the source is left in the adopted state. Pipe binds cannot be moved
+either way.
+
 When an adopted `BoundSocket` connects to a numeric IP literal, `connect(2)` is
 issued synchronously, so [`socket.localAddress`][] is resolved once
 [`socket.connect()`][] returns. Connection failures are still reported via a
@@ -2345,6 +2359,7 @@ net.isIPv6('fhqwhgads'); // returns false
 [`socket.setTimeout()`]: #socketsettimeouttimeout-callback
 [`socket.setTimeout(timeout)`]: #socketsettimeouttimeout-callback
 [`stream.getDefaultHighWaterMark()`]: stream.md#streamgetdefaulthighwatermarkobjectmode
+[`subprocess.send()`]: child_process.md#subprocesssendmessage-sendhandle-options-callback
 [`worker_threads`]: worker_threads.md
 [`writable.destroy()`]: stream.md#writabledestroyerror
 [`writable.destroyed`]: stream.md#writabledestroyed
diff --git a/doc/api/worker_threads.md b/doc/api/worker_threads.md
index e137722674b39b..58d6958d932d3c 100644
--- a/doc/api/worker_threads.md
+++ b/doc/api/worker_threads.md
@@ -1238,7 +1238,7 @@ port2.postMessage(circularData);
 ```
 
 `transferList` may be a list of {ArrayBuffer}, [`MessagePort`][],
-[`FileHandle`][], {net.Server}, and {net.Socket} objects.
+[`FileHandle`][], {net.Server}, {net.Socket}, and {net.BoundSocket} objects.
 After transferring, they are not usable on the sending side of the channel
 anymore (even if they are not contained in `value`).
 
@@ -1249,6 +1249,8 @@ freshly accepted or created TCP connection that has not yet started reading and
 has no buffered data, otherwise `postMessage()` throws
 `ERR_WORKER_HANDLE_NOT_TRANSFERABLE`. This makes it possible to accept
 connections on one thread and distribute them across a pool of worker threads.
+Transferring a {net.BoundSocket} moves an un-adopted pre-bound socket, so a
+port can be reserved synchronously on one thread and adopted on another.
 Only TCP handles are supported.
 
 If `value` contains {SharedArrayBuffer} instances, those are accessible
diff --git a/lib/internal/child_process.js b/lib/internal/child_process.js
index a12b2954db81de..06daf2183db392 100644
--- a/lib/internal/child_process.js
+++ b/lib/internal/child_process.js
@@ -54,6 +54,10 @@ const { TCP } = internalBinding('tcp_wrap');
 const { TTY } = internalBinding('tty_wrap');
 const { UDP } = internalBinding('udp_wrap');
 const SocketList = require('internal/socket_list');
+const {
+  kDeserialize,
+  kTransfer,
+} = require('internal/worker/js_transferable');
 const { owner_symbol } = require('internal/async_hooks').symbols;
 const { convertToValidSignal } = require('internal/util');
 const { isArrayBufferView } = require('internal/util/types');
@@ -86,6 +90,24 @@ const kChannelHandle = Symbol('kChannelHandle');
 const kIsUsedAsStdio = Symbol('kIsUsedAsStdio');
 const kPendingMessages = Symbol('kPendingMessages');
 
+// Store the handle after successfully sending it, so it can be closed when
+// the NODE_HANDLE_ACK is received. If the handle could not be sent, just
+// close it.
+function closeHandleAfterAck(message, handle, options, callback, target) {
+  if (handle && !options.keepOpen) {
+    if (target) {
+      // There can only be one _pendingMessage as passing handles are
+      // processed one at a time: handles are stored in _handleQueue while
+      // waiting for the NODE_HANDLE_ACK of the current passing handle.
+      assert(!target._pendingMessage);
+      target._pendingMessage =
+          { callback, message, handle, options, retransmissions: 0 };
+    } else {
+      handle.close();
+    }
+  }
+}
+
 // This object contain function to convert TCP objects to native handle objects
 // and back again.
 const handleConversion = {
@@ -116,6 +138,29 @@ const handleConversion = {
     },
   },
 
+  'net.BoundSocket': {
+    simultaneousAccepts: true,
+
+    send(message, boundSocket, options) {
+      // Pipe (path) binds cannot be sent over the IPC channel.
+      if (boundSocket.isPipe)
+        throw new ERR_INVALID_HANDLE_TYPE();
+
+      // Reuse the worker_threads transfer protocol: detaches the handle,
+      // leaving the source in the adopted state, and throws if the bound
+      // socket is not in a transferable state.
+      return boundSocket[kTransfer]().data.handle;
+    },
+
+    postSend: closeHandleAfterAck,
+
+    got(message, handle, emit) {
+      const boundSocket = new net._TransferredBoundSocket();
+      boundSocket[kDeserialize]({ handle });
+      emit(boundSocket);
+    },
+  },
+
   'net.Socket': {
     send(message, socket, options) {
       if (!socket._handle)
@@ -165,23 +210,7 @@ const handleConversion = {
       return handle;
     },
 
-    postSend(message, handle, options, callback, target) {
-      // Store the handle after successfully sending it, so it can be closed
-      // when the NODE_HANDLE_ACK is received. If the handle could not be sent,
-      // just close it.
-      if (handle && !options.keepOpen) {
-        if (target) {
-          // There can only be one _pendingMessage as passing handles are
-          // processed one at a time: handles are stored in _handleQueue while
-          // waiting for the NODE_HANDLE_ACK of the current passing handle.
-          assert(!target._pendingMessage);
-          target._pendingMessage =
-              { callback, message, handle, options, retransmissions: 0 };
-        } else {
-          handle.close();
-        }
-      }
-    },
+    postSend: closeHandleAfterAck,
 
     got(message, handle, emit) {
       const socket = new net.Socket({
@@ -822,6 +851,8 @@ function setupChannel(target, channel, serializationMode) {
         message.type = 'net.Socket';
       } else if (handle instanceof net.Server) {
         message.type = 'net.Server';
+      } else if (handle instanceof net.BoundSocket) {
+        message.type = 'net.BoundSocket';
       } else if (handle instanceof TCP || handle instanceof Pipe) {
         message.type = 'net.Native';
       } else if (handle instanceof dgram.Socket) {
diff --git a/lib/net.js b/lib/net.js
index 55fc6ea843cedd..904b4abc297f51 100644
--- a/lib/net.js
+++ b/lib/net.js
@@ -388,6 +388,10 @@ const kBoundPath = Symbol('kBoundPath');
 
 const isLinux = process.platform === 'linux';
 
+// Internal: construct an empty BoundSocket shell during postMessage()
+// deserialization; the transferred handle is installed by [kDeserialize].
+const kBoundSocketDeserialize = Symbol('kBoundSocketDeserialize');
+
 // A role-neutral wrapper over a synchronously bound libuv handle: bound to a
 // local address (a numeric IP literal for TCP, or a filesystem/abstract path
 // for a unix-domain socket via { path }) but neither listening nor connecting
@@ -396,11 +400,20 @@ const isLinux = process.platform === 'linux';
 // handle must be closed by the caller. bind(2) is non-blocking, so binding
 // happens inline and errors throw synchronously. No DNS is performed.
 class BoundSocket {
-  #handle;
+  #handle = null;
   #address = {};
   #path;
 
   constructor(options = kEmptyObject) {
+    // An un-adopted BoundSocket can be moved to another thread by listing it
+    // in the transferList of a worker_threads postMessage() call. See
+    // [kTransfer]().
+    markTransferMode(this, false, true);
+
+    if (options === kBoundSocketDeserialize) {
+      return;
+    }
+
     validateObject(options, 'options');
 
     if (options.path !== undefined) {
@@ -544,7 +557,56 @@ class BoundSocket {
   get isPipe() {
     return this.#path !== undefined;
   }
+
+  // A BoundSocket can be transferred only while it still owns its handle,
+  // i.e. before it has been adopted, closed or already transferred. Only TCP
+  // binds are transferable; pipe handles cannot move between event loops.
+  #assertTransferable() {
+    if (this.#handle === null || !(this.#handle instanceof TCP)) {
+      throw new ERR_WORKER_HANDLE_NOT_TRANSFERABLE('net.BoundSocket');
+    }
+  }
+
+  [kTransferList]() {
+    this.#assertTransferable();
+    return [this.#handle];
+  }
+
+  [kTransfer]() {
+    this.#assertTransferable();
+    const handle = this.#handle;
+    // Detach the handle; the messaging layer takes ownership of it via
+    // TCPWrap::TransferForMessaging(). Further use on the sending side throws
+    // ERR_SOCKET_HANDLE_ADOPTED, as after adoption.
+    this.#handle = null;
+    return {
+      data: { handle },
+      deserializeInfo: 'net:_TransferredBoundSocket',
+    };
+  }
+
+  [kDeserialize](data) {
+    const handle = data?.handle;
+    if (handle == null || !(handle instanceof TCP)) {
+      throw new ERR_WORKER_HANDLE_NOT_TRANSFERABLE('net.BoundSocket');
+    }
+    // Re-derive the bound address from the transferred handle rather than
+    // trusting serialized state.
+    const err = handle.getsockname(this.#address);
+    if (err) {
+      handle.close();
+      throw new ERR_WORKER_HANDLE_NOT_TRANSFERABLE('net.BoundSocket');
+    }
+    this.#handle = handle;
+  }
+}
+
+// Deserialization target for a transferred BoundSocket: constructs an empty
+// shell without binding a new socket. Internal, not part of the public API.
+function _TransferredBoundSocket() {
+  return new BoundSocket(kBoundSocketDeserialize);
 }
+_TransferredBoundSocket.prototype = BoundSocket.prototype;
 
 function Socket(options) {
   if (!(this instanceof Socket)) return new Socket(options);
@@ -2933,6 +2995,7 @@ Server.prototype.unref = function() {
 module.exports = {
   _createServerHandle: createServerHandle,
   _normalizeArgs: normalizeArgs,
+  _TransferredBoundSocket,
   get BlockList() {
     BlockList ??= require('internal/blocklist').BlockList;
     return BlockList;
diff --git a/test/parallel/test-child-process-send-boundsocket.js b/test/parallel/test-child-process-send-boundsocket.js
new file mode 100644
index 00000000000000..fff38a108ec9f6
--- /dev/null
+++ b/test/parallel/test-child-process-send-boundsocket.js
@@ -0,0 +1,79 @@
+'use strict';
+
+// This test verifies that an un-adopted TCP net.BoundSocket can be sent to a
+// child process as the sendHandle argument of subprocess.send(). The parent
+// binds synchronously to reserve the port, then hands the bound socket off;
+// the child adopts it via server.listen() and accepts connections.
+
+const common = require('../common');
+
+const assert = require('assert');
+const net = require('net');
+const { fork } = require('child_process');
+
+if (process.argv[2] === 'child') {
+  process.on('message', common.mustCall((msg, bound) => {
+    assert.ok(bound instanceof net.BoundSocket);
+    // The bound address survives the send.
+    assert.strictEqual(bound.address().port, msg.port);
+
+    const server = net.createServer(common.mustCall((socket) => {
+      socket.end('from-child');
+      server.close();
+    }));
+    server.listen(bound, common.mustCall(() => {
+      assert.strictEqual(server.address().port, msg.port);
+      // Adoption consumed the bound socket.
+      assert.throws(() => bound.address(), {
+        code: 'ERR_SOCKET_HANDLE_ADOPTED',
+      });
+      process.send('listening');
+    }));
+  }));
+  return;
+}
+
+const tmpdir = require('../common/tmpdir');
+tmpdir.refresh();
+
+const child = fork(__filename, ['child']);
+
+// Guards throw synchronously while no handle send is in flight (queued sends
+// defer conversion).
+const pipeBound = new net.BoundSocket({ path: common.PIPE });
+assert.throws(() => child.send('x', pipeBound), {
+  code: 'ERR_INVALID_HANDLE_TYPE',
+});
+pipeBound.close();
+
+const closedBound = new net.BoundSocket({ host: '127.0.0.1', port: 0 });
+closedBound.close();
+assert.throws(() => child.send('x', closedBound), {
+  code: 'ERR_WORKER_HANDLE_NOT_TRANSFERABLE',
+});
+
+const bound = new net.BoundSocket({ host: '127.0.0.1', port: 0 });
+const { port } = bound.address();
+
+child.send({ port }, bound, common.mustSucceed());
+
+// The source is left in the adopted state; further use throws.
+assert.throws(() => bound.address(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+assert.throws(() => bound.fd(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+assert.throws(() => bound.close(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+
+child.on('message', common.mustCall((msg) => {
+  assert.strictEqual(msg, 'listening');
+  const client = net.connect(port, '127.0.0.1');
+  client.setEncoding('utf8');
+  let response = '';
+  client.on('data', (chunk) => { response += chunk; });
+  client.on('end', common.mustCall(() => {
+    assert.strictEqual(response, 'from-child');
+    child.disconnect();
+  }));
+}));
+
+child.on('exit', common.mustCall((code) => {
+  assert.strictEqual(code, 0);
+}));
diff --git a/test/parallel/test-net-boundsocket-transfer-worker.js b/test/parallel/test-net-boundsocket-transfer-worker.js
new file mode 100644
index 00000000000000..054be55d73432a
--- /dev/null
+++ b/test/parallel/test-net-boundsocket-transfer-worker.js
@@ -0,0 +1,64 @@
+'use strict';
+
+// This test verifies that an un-adopted net.BoundSocket can be transferred to
+// a worker thread via worker_threads postMessage()'s transferList. The parent
+// thread binds synchronously to reserve the port, then hands the bound socket
+// off; the worker adopts it via server.listen() and accepts connections.
+
+const common = require('../common');
+
+const assert = require('assert');
+const net = require('net');
+const {
+  Worker,
+  parentPort,
+  threadId,
+  workerData,
+} = require('worker_threads');
+
+if (workerData?.role === 'server') {
+  parentPort.on('message', common.mustCall(({ bound, port }) => {
+    assert.ok(bound instanceof net.BoundSocket);
+    // The bound address survives the transfer.
+    assert.strictEqual(bound.address().port, port);
+
+    const server = net.createServer((socket) => {
+      socket.end(`served-by:${threadId}`);
+    });
+    server.listen(bound, common.mustCall(() => {
+      assert.strictEqual(server.address().port, port);
+      // Adoption consumed the bound socket.
+      assert.throws(() => bound.address(), {
+        code: 'ERR_SOCKET_HANDLE_ADOPTED',
+      });
+      parentPort.postMessage('listening');
+    }));
+  }));
+  return;
+}
+
+const worker = new Worker(__filename, { workerData: { role: 'server' } });
+
+const bound = new net.BoundSocket({ host: '127.0.0.1', port: 0 });
+const { port } = bound.address();
+
+// Move the bound socket to the worker thread.
+worker.postMessage({ bound, port }, [bound]);
+
+// The source is left in the adopted state; further use throws.
+assert.throws(() => bound.address(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+assert.throws(() => bound.fd(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+assert.throws(() => bound.close(), { code: 'ERR_SOCKET_HANDLE_ADOPTED' });
+
+worker.on('message', common.mustCall((msg) => {
+  assert.strictEqual(msg, 'listening');
+  const client = net.connect(port, '127.0.0.1');
+  client.setEncoding('utf8');
+  let response = '';
+  client.on('data', (chunk) => { response += chunk; });
+  client.on('end', common.mustCall(() => {
+    assert.match(response, /^served-by:\d+$/);
+    assert.notStrictEqual(response, `served-by:${threadId}`);
+    worker.terminate();
+  }));
+}));
diff --git a/test/parallel/test-net-transfer-guards.js b/test/parallel/test-net-transfer-guards.js
index 0879ec9da81a8e..d9b836deafbdf8 100644
--- a/test/parallel/test-net-transfer-guards.js
+++ b/test/parallel/test-net-transfer-guards.js
@@ -1,17 +1,31 @@
 'use strict';
 
-// This test verifies the guards that reject transferring a net.Socket or
-// net.Server that is not in a clean, movable state. Serialization is triggered
-// with a MessageChannel, so no worker thread is required.
+// This test verifies the guards that reject transferring a net.Socket,
+// net.Server or net.BoundSocket that is not in a clean, movable state.
+// Serialization is triggered with a MessageChannel, so no worker thread is
+// required.
 
 const common = require('../common');
 
 const assert = require('assert');
 const net = require('net');
 const { MessageChannel } = require('worker_threads');
+const tmpdir = require('../common/tmpdir');
+
+tmpdir.refresh();
 
 const { port1 } = new MessageChannel();
 
+// A pipe BoundSocket is not transferable; only TCP binds can move between
+// event loops.
+{
+  const bound = new net.BoundSocket({ path: common.PIPE });
+  assert.throws(() => port1.postMessage({ bound }, [bound]), {
+    code: 'ERR_WORKER_HANDLE_NOT_TRANSFERABLE',
+  });
+  bound.close();
+}
+
 // A Server that is not listening (no handle) cannot be transferred.
 {
   const server = net.createServer();
@@ -20,6 +34,25 @@ const { port1 } = new MessageChannel();
   });
 }
 
+// A closed BoundSocket no longer owns a handle and cannot be transferred.
+{
+  const bound = new net.BoundSocket({ host: '127.0.0.1', port: 0 });
+  bound.close();
+  assert.throws(() => port1.postMessage({ bound }, [bound]), {
+    code: 'ERR_WORKER_HANDLE_NOT_TRANSFERABLE',
+  });
+}
+
+// An adopted BoundSocket no longer owns a handle and cannot be transferred.
+{
+  const bound = new net.BoundSocket({ host: '127.0.0.1', port: 0 });
+  const socket = new net.Socket({ handle: bound });
+  assert.throws(() => port1.postMessage({ bound }, [bound]), {
+    code: 'ERR_WORKER_HANDLE_NOT_TRANSFERABLE',
+  });
+  socket.destroy();
+}
+
 // A Socket that has already consumed data cannot be transferred, because that
 // buffered data would be lost on the sending side.
 {