nodejs · achingbrain · Feb 18, 2025
diff --git a/lib/internal/quic/quic.js b/lib/internal/quic/quic.js
@@ -1063,7 +1063,7 @@ class QuicSession {
       const length = datagram.byteLength;
       const offset = datagram.byteOffset;
       datagram = new Uint8Array(ArrayBufferPrototypeTransfer(datagram.buffer),
-                                length, offset);
+                                offset, length);
     }
 
     debug(`sending datagram with ${datagram.byteLength} bytes`);

diff --git a/test/parallel/test-quic-datagrams.js b/test/parallel/test-quic-datagrams.js
@@ -0,0 +1,128 @@
+// Flags: --experimental-quic --no-warnings
+'use strict';
+
+const { hasQuic } = require('../common');
+const {
+  deepStrictEqual
+} = require('node:assert');
+const {
+  describe,
+  it,
+  beforeEach,
+  afterEach
+} = require('node:test');
+
+const skip = !hasQuic;
+
+const STRING_DATAGRAMS = ['hello', 'world']
+
+const encoder = new TextEncoder()
+const BUF_DATAGRAMS = STRING_DATAGRAMS.map(str => encoder.encode(str))
+
+async function delay (ms) {
+  await new Promise((resolve) => {
+    setTimeout(() => {
+      resolve()
+    }, ms)
+  })
+}
+
+async function sendDatagrams(sender, receiver, datagrams) {
+  const allDatagramsReceived = Promise.withResolvers();
+  const datagramsReceived = [];
+
+  // TODO: currently only the first datagram is received, and it's received many
+  // times so this test will not pass
+  receiver.ondatagram = (datagram) => {
+    datagramsReceived.push(datagram);
+
+    if (datagramsReceived.length === datagrams.length) {
+      allDatagramsReceived.resolve();
+    }
+  };
+
+  for (const datagram of datagrams) {
+    await sender.sendDatagram(datagram);
+  }
+
+  await allDatagramsReceived.promise;
+
+  for (let i = 0; i < datagrams.length; i++) {
+    deepStrictEqual(datagramsReceived[i], datagrams[i]);
+  }
+}
+
+describe('quic datagrams', { skip }, async () => {
+  const { createPrivateKey } = require('node:crypto');
+  const fixtures = require('../common/fixtures');
+  const keys = createPrivateKey(fixtures.readKey('agent1-key.pem'));
+  const certs = fixtures.readKey('agent1-cert.pem');
+  let serverEndpoint
+  let clientSession
+  let serverSession
+
+  const {
+    listen,
+    connect,
+  } = require('node:quic');
+
+  beforeEach(async () => {
+    const clientConnected = Promise.withResolvers();
+
+    serverEndpoint = await listen((serverSession) => {
+      serverSession.opened.then(() => {
+        clientConnected.resolve(serverSession);
+      });
+    }, { keys, certs });
+
+    clientSession = await connect(serverEndpoint.address);
+    await clientSession.opened;
+
+    serverSession = await clientConnected.promise;
+  })
+
+  afterEach(async () => {
+    // TODO: calling `.close` on `serverEndpoint` without first closing both
+    // sessions causes a segfault - we should be able to stop the listener
+    // without manually closing all sessions first
+    await clientSession?.close();
+    await serverSession?.close();
+    await serverEndpoint?.close();
+  })
+
+  it('a quic client can send ArrayBufferView datagrams to a server', async () => {
+    // TODO: if this delay is removed, `can_send_packets` in `session.cc`
+    // returns false and the datagram is not sent - after the `.opened` promise
+    // resolves we should be able to send datagrams without additional delays
+    await delay(500);
+
+    await sendDatagrams(clientSession, serverSession, BUF_DATAGRAMS);
+  });
+
+  it('a quic server can send ArrayBufferView datagrams to a client', async () => {
+    // TODO: if this delay is removed, `can_send_packets` in `session.cc`
+    // returns false and the datagram is not sent - after the `.opened` promise
+    // resolves we should be able to send datagrams without additional delays
+    await delay(500);
+
+    await sendDatagrams(serverSession, clientSession, BUF_DATAGRAMS);
+  });
+
+  it('a quic client can send String datagrams to a server', async () => {
+    // TODO: if this delay is removed, `can_send_packets` in `session.cc`
+    // returns false and the datagram is not sent - after the `.opened` promise
+    // resolves we should be able to send datagrams without additional delays
+    await delay(500);
+
+    await sendDatagrams(clientSession, serverSession, STRING_DATAGRAMS);
+  });
+
+  it('a quic server can send String datagrams to a client', async () => {
+    // TODO: if this delay is removed, `can_send_packets` in `session.cc`
+    // returns false and the datagram is not sent - after the `.opened` promise
+    // resolves we should be able to send datagrams without additional delays
+    await delay(500);
+
+    await sendDatagrams(serverSession, clientSession, STRING_DATAGRAMS);
+  });
+});