cf_tunnel.ts

import { decodeBase64 } from "https://deno.land/std@0.212.0/encoding/base64.ts";

const CLIENT_ID = crypto.randomUUID();

const [{ port, target }] = await Deno.resolveDns(
  "_v2-origintunneld._tcp.argotunnel.com",
  "SRV",
);
const [address] = await Deno.resolveDns(target, "A");

const quickTun = await fetch("https://api.trycloudflare.com/tunnel", {
  method: "POST",
}).then((r) => r.json());

console.log(quickTun);

const conn = await Deno.connectQuic({
  hostname: address,
  port,
  serverName: "quic.cftunnel.com",
  caCerts: [
    await Deno.readTextFile("./cf_root.pem"),
  ],
});

const helperSock = await Deno.connect({ port: 8080 });
const encoder = new TextEncoder();
const decoder = new TextDecoder('utf8');
const writer = helperSock.writable.getWriter();
const reader = helperSock.readable.getReader();
const rpc = async (req: object) => {
  await writer.write(encoder.encode(JSON.stringify(req) + '\n'));
  const { value } = await reader.read();
  return JSON.parse(decoder.decode(value));
};

handleControlStream(conn);
handleRequests(conn);

async function handleControlStream(quic: Deno.QuicConn) {
  const bi = await quic.createBidirectionalStream();

  const pain1 = await Deno.connect({ port: 8080 });
  pain1.readable.pipeTo(bi.writable).catch(console.error);
  bi.readable.pipeTo(pain1.writable).catch(console.error);

  console.log(await rpc({
    RegisterConnection: {
      account_tag: quickTun.result.account_tag,
      tunnel_secret: [...decodeBase64(quickTun.result.secret)],
      tunnel_id: quickTun.result.id,
      conn_index: 0,
      client_id: CLIENT_ID,
    },
  }));
}

const DATA_SIG = [0x0A, 0x36, 0xCD, 0x12, 0xA1, 0x3E];
function isSig(got: number[], cmp: number[]) {
  if (got.length !== cmp.length) {
    return false;
  }
  for (let i = 0; i < got.length; i += 1) {
    if (got[i] !== cmp[i]) {
      return false;
    }
  }
  return true;
}

async function handleRequests(conn: Deno.QuicConn) {
  for await (const bi of conn.incomingBidirectionalStreams) {
    const reader = bi.readable.getReader({ mode: 'byob' });
    const writer = bi.writable.getWriter();
    const { value: sig } = await reader.read(new Uint8Array(6));
    if (isSig(sig, DATA_SIG)) {
      const { value: version } = await reader.read(new Uint8Array(2));

      const req = await readQuicRequest(reader);

      let body = encoder.encode('no body :(');
      const bodyLen = req.metadata['HttpHeader:Content-Length'];
      if (bodyLen) {
        ({ value: body } = await reader.read(new Uint8Array(+bodyLen)));
      }

      await writer.write(new Uint8Array(DATA_SIG));
      await writer.write(new Uint8Array([0x30, 0x31]));

      const res = await rpc({
        QuicConnectResponse: {
          metadata: {
            'HttpStatus': '200',
            'HttpHeader:Content-Length': body.length.toString(),
            'HttpHeader:Content-Type': 'text/plain',
          },
        },
      });
      await writer.write(new Uint8Array(res.data));
      await writer.write(body);
      await writer.close();
    } else {
      console.log('unknown sig', sig);
    }
  }
}

async function readQuicRequest(reader: ReadableStreamBYOBReader) {
  const data = [];
  const { value: buf } = await reader.read(new Uint8Array(8));
  data.push(...buf!);
  const [segmentCount, firstSegmentLen] = parseSegmentTableFirst(buf!);
  let totalSegmentLength = firstSegmentLen;
  if (segmentCount > 1) {
    const { value: segmentSizes } = await reader.read(new Uint8Array(segmentCount * 4));
    data.push(segmentSizes);
    const view = new DataView(segmentSizes!.buffer);
    for (let i = 0; i < (segmentCount - 1); i += 1) {
      const len = view.getUint32(i * 4, true);
      totalSegmentLength += len;
    }
  }
  const { value: encoded } = await reader.read(new Uint8Array(totalSegmentLength * 8));
  const req = await rpc({
    QuicConnectRequest: {
      data: [...data, ...encoded!],
    },
  });
  return req;
}

function parseSegmentTableFirst(buf: Uint8Array) {
  const view = new DataView(buf.buffer);
  const segmentCount = view.getUint32(0, true) + 1;
  if (segmentCount > 512 || segmentCount === 0) {
    throw new Error(`Invalid segment count: ${segmentCount}`);
  }
  const firstSegmentLen = view.getUint32(4, true);
  return [segmentCount, firstSegmentLen];
}