refactor code

handlers.ts

@@ -0,0 +1,136 @@
+import { sock } from "./server.js";
+import { Commands, CommandsByValue } from "./func_replacements.js";
+import { createWriteStream } from "node:fs";
+import { SendUsrAck, SendUsrChk, create_P2pRdy } from "./impl.js";
+
+let image_fds = [];
+let cur_image_index = 0;
+let size_so_far = 0;
+
+export const notImpl = (_: sock, dv: DataView) => {
+  const raw = dv.readU16();
+  const cmd = CommandsByValue[raw];
+  console.log(`^^ ${cmd} (${raw.toString(16)}) and it's not implemented yet`);
+};
+
+export const noop = (_: sock, __: DataView) => {};
+const create_P2pAliveAck = (): DataView => {
+  const outbuf = new DataView(new Uint8Array(4).buffer);
+  outbuf.writeU16(Commands.P2PAliveAck);
+  outbuf.add(2).writeU16(0);
+  return outbuf;
+};
+
+export const handle_P2PAlive = (sock: sock, _: DataView) => {
+  const b = create_P2pAliveAck();
+  sock.send(b);
+};
+export const handle_PunchPkt = (sock: sock, dv: DataView) => {
+  const punchCmd = dv.readU16();
+  const len = dv.add(2).readU16();
+  const prefix = dv.add(4).readString(4);
+  const serial = dv.add(8).readU64().toString();
+  const suffix = dv.add(16).readString(4);
+  // f141 20 BATC 609531 EXLV
+  sock.send(create_P2pRdy(dv.add(4).readByteArray(len)));
+};
+
+const deal_with_control = (sock: sock, dv: DataView) => {
+  const start_type = dv.add(8).readU16(); // 0xa11 on control; data starts here on DATA pkt
+  const cmd_id = dv.add(10).readU16(); // 0x1120
+
+  if (start_type != 0x110a) {
+    console.error(`Expected start_type to be 0xa11, got 0x${start_type.toString(16)}`);
+    return;
+  }
+
+  if (cmd_id == ControlCommands.ConnectUserAck) {
+    /*
+      00000000  f1 d0 00 18 d1 00 00 00 11 0a 20 11 0c 00 ff 00  .......... .....
+      00000010  00 00 00 00 34 54 63 4d fe 01 01 01              ....4TcM....
+                            ^^^^^^^^^^^
+                            some kind of challenge
+                            need to send the 0x3010
+                            command with these 4 bytes 'encrypted'
+      */
+    let challenge = [0, 0, 0, 0];
+    challenge[0] = dv.add(0x14).readU8();
+    challenge[1] = dv.add(0x15).readU8();
+    challenge[2] = dv.add(0x16).readU8();
+    challenge[3] = dv.add(0x17).readU8();
+    const buf = SendUsrAck(challenge);
+    sock.send(buf);
+  }
+};
+
+const deal_with_data = (dv: DataView) => {
+  const pkt_len = dv.add(2).readU16();
+  // data
+  const JPEG_HEADER = [0xff, 0xd8, 0xff, 0xdb];
+  const AUDIO_HEADER = [0x55, 0xaa, 0x15, 0xa8];
+  const m_hdr = dv.add(8).readByteArray(4);
+  let is_new_image = true;
+  let audio = true;
+  for (let i = 0; i < 4; i++) {
+    is_new_image = is_new_image && m_hdr.add(i).readU8() == JPEG_HEADER[i];
+    audio = audio && m_hdr.add(i).readU8() == AUDIO_HEADER[i];
+  }
+
+  if (audio) {
+    // TODO audio pkt
+  } else {
+    if (is_new_image) {
+      size_so_far = 0;
+      if (cur_image_index > 0) {
+        image_fds[cur_image_index - 1].close();
+      }
+      const fname = `captures/${cur_image_index.toString().padStart(4, "0")}.jpg`;
+      let cur_image = createWriteStream(fname);
+      cur_image.cork();
+      image_fds[cur_image_index] = cur_image;
+      cur_image_index++;
+    }
+
+    const data = dv.add(8).readByteArray(pkt_len - 4);
+    image_fds[cur_image_index - 1].write(Buffer.from(data.buffer));
+    size_so_far += pkt_len - 4;
+  }
+};
+
+const ControlCommands = {
+  ConnectUser: 0x2010,
+  ConnectUserAck: 0x2011,
+};
+
+const makeDrwAck = (dv: DataView): DataView => {
+  const pkt_id = dv.add(6).readU16();
+  const m_stream = dv.add(5).readU8(); // data = 1, control = 0
+  const item_count = 1; // TODO coalesce acks
+  const reply_len = item_count * 2 + 4; // 4 hdr, 2b per item
+  const outbuf = new DataView(new Uint8Array(32).buffer);
+  outbuf.writeU16(Commands.DrwAck);
+  outbuf.add(2).writeU16(reply_len);
+  outbuf.add(4).writeU8(0xd2);
+  outbuf.add(5).writeU8(m_stream);
+  outbuf.add(6).writeU16(item_count);
+  for (let i = 0; i < item_count; i++) {
+    outbuf.add(8 + i * 2).writeU16(pkt_id);
+  }
+  return outbuf;
+};
+export const handle_Drw = (sock: sock, dv: DataView) => {
+  const ack = makeDrwAck(dv);
+  sock.send(ack);
+
+  const m_stream = dv.add(5).readU8(); // data = 1, control = 0
+  if (m_stream == 1) {
+    deal_with_data(dv);
+  } else {
+    deal_with_control(sock, dv);
+  }
+};
+
+export const handle_P2PRdy = (sock: sock, _: DataView) => {
+  const b = SendUsrChk("admin", "admin");
+  sock.send(b);
+};