idz: Add type defs for common net comms context

src/idz/common/index.ts

@@ -1,4 +1,5 @@
 import setup from "./setup";
 
 export { BLOCK_SIZE } from "./aes";
+export { ClientHello } from "./setup";
 export default setup;

src/idz/common/setup.ts

@@ -2,7 +2,7 @@ import { Socket } from "net";
 
 import AesEcbStream from "./aes";
 import { readBigInt, modPow, writeBigInt } from "./bigint";
-import IoByteStream from "../../util/stream";
+import IoByteStream, { ByteStream } from "../../util/stream";
 
 interface RsaKey {
   N: bigint;
@@ -11,6 +11,17 @@ interface RsaKey {
   hashN: number;
 }
 
+export interface ClientHello {
+  pcbId: string;
+  protocol: string;
+  model: string;
+}
+
+export interface IdzConnection {
+  aesStream: ByteStream;
+  clientHello: ClientHello;
+}
+
 // Proof-of-concept, so we only ever use one of the ten RSA key pairs
 const rsaKey = {
   N: 4922323266120814292574970172377860734034664704992758249880018618131907367614177800329506877981986877921220485681998287752778495334541127048495486311792061n,
@@ -22,7 +33,7 @@ const rsaKey = {
 // Proof-of-concept, so we only use one fixed session key
 const aesKey = Buffer.from("ffddeeccbbaa99887766554433221100", "hex");
 
-function writeServerHello(aesKey: Buffer, rsaKey: RsaKey) {
+function writeServerHello(aesKey: Buffer, rsaKey: RsaKey): Buffer {
   const M = readBigInt(aesKey);
   const keyEnc = modPow(M, rsaKey.e, rsaKey.N);
   const result = Buffer.alloc(0x48);
@@ -50,7 +61,7 @@ function readClientHello(buf: Buffer) {
   };
 }
 
-export default async function setup(socket: Socket) {
+export default async function setup(socket: Socket): Promise<IdzConnection> {
   const tcpStream = new IoByteStream(socket);
   const serverHello = writeServerHello(aesKey, rsaKey);