* 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 re
(webSocket, vlessResponseHeader, log)
| 719 | * @returns {{write: (chunk: Uint8Array) => void}} An object with a write method that accepts a Uint8Array chunk to write to the transform stream. |
| 720 | */ |
| 721 | async function handleUDPOutBound(webSocket, vlessResponseHeader, log) { |
| 722 | |
| 723 | let isVlessHeaderSent = false; |
| 724 | const transformStream = new TransformStream({ |
| 725 | start(controller) { |
| 726 | |
| 727 | }, |
| 728 | transform(chunk, controller) { |
| 729 | // udp message 2 byte is the the length of udp data |
| 730 | // TODO: this should have bug, beacsue maybe udp chunk can be in two websocket message |
| 731 | for (let index = 0; index < chunk.byteLength;) { |
| 732 | const lengthBuffer = chunk.slice(index, index + 2); |
| 733 | const udpPakcetLength = new DataView(lengthBuffer).getUint16(0); |
| 734 | const udpData = new Uint8Array( |
| 735 | chunk.slice(index + 2, index + 2 + udpPakcetLength) |
| 736 | ); |
| 737 | index = index + 2 + udpPakcetLength; |
| 738 | controller.enqueue(udpData); |
| 739 | } |
| 740 | }, |
| 741 | flush(controller) { |
| 742 | } |
| 743 | }); |
| 744 | |
| 745 | // only handle dns udp for now |
| 746 | transformStream.readable.pipeTo(new WritableStream({ |
| 747 | async write(chunk) { |
| 748 | const resp = await fetch(dohURL, // dns server url |
| 749 | { |
| 750 | method: 'POST', |
| 751 | headers: { |
| 752 | 'content-type': 'application/dns-message', |
| 753 | }, |
| 754 | body: chunk, |
| 755 | }) |
| 756 | const dnsQueryResult = await resp.arrayBuffer(); |
| 757 | const udpSize = dnsQueryResult.byteLength; |
| 758 | // console.log([...new Uint8Array(dnsQueryResult)].map((x) => x.toString(16))); |
| 759 | const udpSizeBuffer = new Uint8Array([(udpSize >> 8) & 0xff, udpSize & 0xff]); |
| 760 | if (webSocket.readyState === WS_READY_STATE_OPEN) { |
| 761 | log(`doh success and dns message length is ${udpSize}`); |
| 762 | if (isVlessHeaderSent) { |
| 763 | webSocket.send(await new Blob([udpSizeBuffer, dnsQueryResult]).arrayBuffer()); |
| 764 | } else { |
| 765 | webSocket.send(await new Blob([vlessResponseHeader, udpSizeBuffer, dnsQueryResult]).arrayBuffer()); |
| 766 | isVlessHeaderSent = true; |
| 767 | } |
| 768 | } |
| 769 | } |
| 770 | })).catch((error) => { |
| 771 | log('dns udp has error' + error) |
| 772 | }); |
| 773 | |
| 774 | const writer = transformStream.writable.getWriter(); |
| 775 | |
| 776 | return { |
| 777 | /** |
| 778 | * |