* Handles outbound UDP traffic by transforming the data into DNS queries and sending them over a WebSocket connection. * @param {import("@cloudflare/workers-types").WebSocket} webSocket The WebSocket connection to send the DNS queries over. * @param {ArrayBuffer} vlessResponseHeader The VLESS resp
(webSocket, vlessResponseHeader, log)
| 643 | * @returns {{write: (chunk: Uint8Array) => void}} An object with a write method that accepts a Uint8Array chunk to write to the transform stream. |
| 644 | */ |
| 645 | async function handleUDPOutBound(webSocket, vlessResponseHeader, log) { |
| 646 | |
| 647 | let isVlessHeaderSent = false; |
| 648 | const transformStream = new TransformStream({ |
| 649 | start(controller) { |
| 650 | |
| 651 | }, |
| 652 | transform(chunk, controller) { |
| 653 | // udp message 2 byte is the the length of udp data |
| 654 | // TODO: this should have bug, beacsue maybe udp chunk can be in two websocket message |
| 655 | for (let index = 0; index < chunk.byteLength;) { |
| 656 | const lengthBuffer = chunk.slice(index, index + 2); |
| 657 | const udpPakcetLength = new DataView(lengthBuffer).getUint16(0); |
| 658 | const udpData = new Uint8Array( |
| 659 | chunk.slice(index + 2, index + 2 + udpPakcetLength) |
| 660 | ); |
| 661 | index = index + 2 + udpPakcetLength; |
| 662 | controller.enqueue(udpData); |
| 663 | } |
| 664 | }, |
| 665 | flush(controller) { |
| 666 | } |
| 667 | }); |
| 668 | |
| 669 | // only handle dns udp for now |
| 670 | transformStream.readable.pipeTo(new WritableStream({ |
| 671 | async write(chunk) { |
| 672 | const resp = await fetch(dohURL, // dns server url |
| 673 | { |
| 674 | method: 'POST', |
| 675 | headers: { |
| 676 | 'content-type': 'application/dns-message', |
| 677 | }, |
| 678 | body: chunk, |
| 679 | }) |
| 680 | const dnsQueryResult = await resp.arrayBuffer(); |
| 681 | const udpSize = dnsQueryResult.byteLength; |
| 682 | // console.log([...new Uint8Array(dnsQueryResult)].map((x) => x.toString(16))); |
| 683 | const udpSizeBuffer = new Uint8Array([(udpSize >> 8) & 0xff, udpSize & 0xff]); |
| 684 | if (webSocket.readyState === WS_READY_STATE_OPEN) { |
| 685 | log(`doh success and dns message length is ${udpSize}`); |
| 686 | if (isVlessHeaderSent) { |
| 687 | webSocket.send(await new Blob([udpSizeBuffer, dnsQueryResult]).arrayBuffer()); |
| 688 | } else { |
| 689 | webSocket.send(await new Blob([vlessResponseHeader, udpSizeBuffer, dnsQueryResult]).arrayBuffer()); |
| 690 | isVlessHeaderSent = true; |
| 691 | } |
| 692 | } |
| 693 | } |
| 694 | })).catch((error) => { |
| 695 | log('dns udp has error' + error) |
| 696 | }); |
| 697 | |
| 698 | const writer = transformStream.writable.getWriter(); |
| 699 | |
| 700 | return { |
| 701 | /** |
| 702 | * |