fix(ext/node): UdpSocket ref and unref (#21777)

4 files changed, 89 insertions, 4 deletions

diff --git a/cli/tests/integration/node_unit_tests.rs b/cli/tests/integration/node_unit_tests.rs
index 5e53a63c5..1508ad9ac 100644
--- a/cli/tests/integration/node_unit_tests.rs
+++ b/cli/tests/integration/node_unit_tests.rs
@@ -58,6 +58,7 @@ util::unit_test_factory!(
     crypto_key_test = crypto / crypto_key_test,
     crypto_sign_test = crypto / crypto_sign_test,
     events_test,
+    dgram_test,
     fs_test,
     http_test,
     http2_test,
diff --git a/cli/tests/unit_node/dgram_test.ts b/cli/tests/unit_node/dgram_test.ts
new file mode 100644
index 000000000..d532241f5
--- /dev/null
+++ b/cli/tests/unit_node/dgram_test.ts
@@ -0,0 +1,59 @@
+// Copyright 2018-2024 the Deno authors. All rights reserved. MIT license.
+
+import { assertEquals } from "../../../test_util/std/assert/mod.ts";
+import { execCode } from "../unit/test_util.ts";
+import { createSocket } from "node:dgram";
+
+const listenPort = 4503;
+const listenPort2 = 4504;
+
+Deno.test("[node/dgram] udp ref and unref", {
+  permissions: { read: true, run: true, net: true },
+}, async () => {
+  const { promise, resolve } = Promise.withResolvers<void>();
+
+  const udpSocket = createSocket("udp4");
+  udpSocket.bind(listenPort);
+
+  udpSocket.unref();
+  udpSocket.ref();
+
+  let data;
+  udpSocket.on("message", (buffer, _rinfo) => {
+    data = Uint8Array.from(buffer);
+    udpSocket.close();
+  });
+  udpSocket.on("close", () => {
+    resolve();
+  });
+
+  const conn = await Deno.listenDatagram({
+    port: listenPort2,
+    transport: "udp",
+  });
+  await conn.send(new Uint8Array([0, 1, 2, 3]), {
+    transport: "udp",
+    port: listenPort,
+    hostname: "127.0.0.1",
+  });
+
+  await promise;
+  conn.close();
+  assertEquals(data, new Uint8Array([0, 1, 2, 3]));
+});
+
+Deno.test("[node/dgram] udp unref", {
+  permissions: { read: true, run: true, net: true },
+}, async () => {
+  const [statusCode, _output] = await execCode(`
+      import { createSocket } from "node:dgram";
+      const udpSocket = createSocket('udp4');
+      udpSocket.bind(${listenPort2});
+      // This should let the program to exit without waiting for the
+      // udp socket to close.
+      udpSocket.unref();
+      udpSocket.on('message', (buffer, rinfo) => {
+      });
+    `);
+  assertEquals(statusCode, 0);
+});
diff --git a/ext/net/01_net.js b/ext/net/01_net.js
index c4a921536..699423b22 100644
--- a/ext/net/01_net.js
+++ b/ext/net/01_net.js
@@ -295,6 +295,8 @@ class Listener {
 class Datagram {
   #rid = 0;
   #addr = null;
+  #unref = false;
+  #promise = null;
 
   constructor(rid, addr, bufSize = 1024) {
     this.#rid = rid;
@@ -367,10 +369,12 @@ class Datagram {
     let remoteAddr;
     switch (this.addr.transport) {
       case "udp": {
-        ({ 0: nread, 1: remoteAddr } = await op_net_recv_udp(
+        this.#promise = op_net_recv_udp(
           this.rid,
           buf,
-        ));
+        );
+        if (this.#unref) core.unrefOpPromise(this.#promise);
+        ({ 0: nread, 1: remoteAddr } = await this.#promise);
         remoteAddr.transport = "udp";
         break;
       }
@@ -413,6 +417,20 @@ class Datagram {
     core.close(this.rid);
   }
 
+  ref() {
+    this.#unref = false;
+    if (this.#promise !== null) {
+      core.refOpPromise(this.#promise);
+    }
+  }
+
+  unref() {
+    this.#unref = true;
+    if (this.#promise !== null) {
+      core.unrefOpPromise(this.#promise);
+    }
+  }
+
   async *[SymbolAsyncIterator]() {
     while (true) {
       try {
diff --git a/ext/node/polyfills/internal_binding/udp_wrap.ts b/ext/node/polyfills/internal_binding/udp_wrap.ts
index 619950997..209c84a23 100644
--- a/ext/node/polyfills/internal_binding/udp_wrap.ts
+++ b/ext/node/polyfills/internal_binding/udp_wrap.ts
@@ -78,6 +78,7 @@ export class UDP extends HandleWrap {
 
   #listener?: Deno.DatagramConn;
   #receiving = false;
+  #unrefed = false;
 
   #recvBufferSize = UDP_DGRAM_MAXSIZE;
   #sendBufferSize = UDP_DGRAM_MAXSIZE;
@@ -273,7 +274,8 @@ export class UDP extends HandleWrap {
   }
 
   override ref() {
-    notImplemented("udp.UDP.prototype.ref");
+    this.#listener?.ref();
+    this.#unrefed = false;
   }
 
   send(
@@ -315,7 +317,8 @@ export class UDP extends HandleWrap {
   }
 
   override unref() {
-    notImplemented("udp.UDP.prototype.unref");
+    this.#listener?.unref();
+    this.#unrefed = true;
   }
 
   #doBind(ip: string, port: number, _flags: number, family: number): number {
@@ -443,6 +446,10 @@ export class UDP extends HandleWrap {
     let remoteAddr: Deno.NetAddr | null;
     let nread: number | null;
 
+    if (this.#unrefed) {
+      this.#listener!.unref();
+    }
+
     try {
       [buf, remoteAddr] = (await this.#listener!.receive(p)) as [
         Uint8Array,