Multicast UDPSocket support in wpt #55304
Description
There is a new web feature that allows to subscribe to UDP multicast groups to receive UDP packets there.
See the explainer https://github.com/WICG/direct-sockets/blob/main/docs/multicast-explainer.md
Multicast tests work in Chrome browser tests except on MacOS (known chromium issue) content/browser/direct_sockets/direct_sockets_udp_browsertest.cc
WPT the environment is too restrictive, and packets are not arrived at multicast group silently. The path to WPT tests in chromium: third_party/blink/web_tests/external/wpt/direct-sockets/udp_socket.https.html
Run tests: autoninja -C out/Default blink_tests && third_party/blink/tools/run_web_tests.py --target Default virtual/direct-sockets --verbose --gtest_filter multicast.https.html,multicast.https.html.headers --driver-logging --timeout-ms 5000 --no-retry-failures
When it is fixed, the tests can be added as shown in the code
<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="/resources/test-only-api.js"></script>
<script>
'use strict';
// The test creates:
// 2 bound sockets that subscribe to the same group for reading
// 1 bound socket that sends data to the group.
// Test is finished when all messages are received by all subscribers.
// parameters:
// multicastAllowAddressSharing = true. to have 2 subscribers on the same machine.
// multicastTimeToLive = 0. To not try to send data outside of this machine.
// multicastLoopback = true. To get the packet back.
// It is fine to reuse the same address, because
// the port will be generated unique on this machine.
// multicast addresses are in range 224.0.0.0 to 239.255.255.255.
const multicastGroupAddress = '237.132.100.17';
const kRequiredDatagrams = 150;
const kRequiredBytes =
kRequiredDatagrams * (kRequiredDatagrams + 1) / 2;
class MulticastReader {
constructor(multicastPort) {
this.socket = new UDPSocket({
localAddress: '0.0.0.0',
localPort: multicastPort,
multicastAllowAddressSharing: true
});
}
async create() {
const { readable, multicastController, localAddress, localPort } = await this.socket.opened;
await multicastController.joinGroup(multicastGroupAddress);
this.readable = readable;
this.multicastController = multicastController;
this.localPort = localPort;
console.log('reading socket is opened and joinedGroup at ' + localAddress + ':' + localPort);
}
async read() {
const reader = this.readable.getReader();
let bytesRead = 0;
while (bytesRead < kRequiredBytes) {
const { value: { data }, done } = await reader.read();
assert_false(done);
console.log('first piece of data was received! ' + data.length);
for (let index = 0; index < data.length; index++) {
assert_equals(data[index], bytesRead % 256);
bytesRead++;
}
}
assert_equals(bytesRead, kRequiredBytes);
reader.releaseLock();
await this.socket.close();
console.log('all data has been read');
}
}
promise_test(async () => {
const senderSocket = new UDPSocket({ localAddress: '127.0.0.1',
multicastTimeToLive: 0,
multicastLoopback: true });
const { writable } = await senderSocket.opened;
console.log('sender udp socket is opened ');
// Pass undefined as multicastPort, so it will be allocated.
const multicastReader1 = new MulticastReader(undefined);
await multicastReader1.create();
const multicastPort = multicastReader1.localPort;
const multicastReader2 = new MulticastReader(multicastPort);
await multicastReader2.create();
const readLoop1 = (async () => {
console.log('read loop for the first socket is started');
await multicastReader1.read();
})();
const readLoop2 = (async () => {
console.log('read loop for the second socket is started');
await multicastReader2.read();
})();
const sendLoop = (async () => {
let bytesWritten = 0;
let chunkLength = 0;
const writer = writable.getWriter();
while (bytesWritten < kRequiredBytes) {
chunkLength = Math.min(chunkLength + 1, kRequiredBytes - bytesWritten);
let chunk = new Uint8Array(chunkLength);
for (let index = 0; index < chunkLength; index++) {
chunk[index] = bytesWritten % 256;
bytesWritten++;
}
await writer.ready;
await writer.write({
data: chunk,
remoteAddress: multicastGroupAddress,
remotePort: multicastPort
});
}
assert_equals(bytesWritten, kRequiredBytes);
writer.releaseLock();
await senderSocket.close();
console.log('all data has been sent');
})();
await sendLoop;
await readLoop1;
await readLoop2;
}, "UDPSocket sends messages to a multicast group that has 2 subscribers");
</script>