From d675a44b4e77a1c0aa2210f5bea3d538476f63ac Mon Sep 17 00:00:00 2001
From: Derrick Hammer <derrick@derrickhammer.com>
Date: Wed, 2 Aug 2023 17:03:06 -0400
Subject: [PATCH] feat: add dns query api that uses mock sockets and a
 dedicated hyper proxy for DNS (port 53) requests

---
 src/dns/tcpClient.ts | 132 +++++++++++++++++++++++++++++++++++++++++++
 src/index.ts         |  35 +++++++++++-
 2 files changed, 166 insertions(+), 1 deletion(-)
 create mode 100644 src/dns/tcpClient.ts

diff --git a/src/dns/tcpClient.ts b/src/dns/tcpClient.ts
new file mode 100644
index 0000000..82b24e3
--- /dev/null
+++ b/src/dns/tcpClient.ts
@@ -0,0 +1,132 @@
+import { Client as Base, TCPSocket } from "bns/lib/internal/net.js";
+import IP from "binet";
+import { Duplex } from "streamx";
+import { MultiSocketProxy } from "@lumeweb/libhyperproxy";
+import defer from "p-defer";
+
+class Stream extends Duplex {
+  public remoteAddress = "127.0.0.1";
+  public family = "IPv4";
+  public port = 0;
+  public remotePort = 0;
+  public parent: any;
+
+  constructor(options) {
+    super(options);
+    this.parent = options.parent;
+  }
+
+  setNoDelay() {}
+
+  connect() {
+    setTimeout(() => {
+      // @ts-ignore
+      this.emit("connect");
+    }, 1);
+  }
+
+  unref() {}
+}
+
+const PROTOCOL = "lumeweb.proxy.handshake.dns";
+
+export default class TCPClient extends Base {
+  private node: any;
+  private proxy: MultiSocketProxy;
+  private peerConnected = defer();
+
+  constructor(options) {
+    super(options);
+
+    this.node = options.node;
+    this.proxy = new MultiSocketProxy({
+      protocol: PROTOCOL,
+      swarm: options.swarm,
+      server: false,
+      autostart: true,
+      listen: true,
+    });
+
+    this.proxy.on("peerChannelOpen", () => {
+      this.peerConnected.resolve();
+    });
+  }
+
+  protected declare sockets: Map<any, any>;
+
+  async write(msg, port, host) {
+    const local = host === "127.0.0.1";
+    const key = IP.toHost(host, port);
+    const cache = this.sockets.get(key);
+
+    if (cache) {
+      cache.write(msg);
+      return;
+    }
+
+    let socket: any = null;
+
+    try {
+      if (local) {
+        socket = await this.createLocalSocket();
+      } else {
+        await this.peerConnected.promise;
+        socket = new TCPSocket(this);
+        socket.socket = this.proxy.createSocket({
+          host,
+          port,
+        });
+        socket.socket.remoteAddress = host;
+        socket.socket.remotePort = port;
+
+        await socket.connect();
+      }
+    } catch (e) {
+      return;
+    }
+
+    if (this.sockets.has(key)) {
+      socket.destroy();
+      socket = this.sockets.get(key);
+    } else {
+      socket.parent = this;
+      this.sockets.set(key, socket);
+    }
+
+    socket.write(msg);
+  }
+
+  async createLocalSocket() {
+    const socket = new TCPSocket(this);
+    const remoteSocket = new Stream({
+      parent: this,
+      write: (data, cb) => {
+        // @ts-ignore
+        socket.socket.push(data);
+        cb?.(null);
+      },
+    });
+    // @ts-ignore
+    socket.socket = new Stream({
+      parent: this,
+      write: (data, cb) => {
+        // @ts-ignore
+        remoteSocket.push(data);
+        cb?.(null);
+      },
+    });
+    const port = this.node.rs.hns.getAuthority().servers.slice().pop().port;
+    remoteSocket.port = port;
+    remoteSocket.remotePort = port;
+    // @ts-ignore
+    socket.socket.port = port;
+    // @ts-ignore
+    socket.socket.remotePort = port;
+
+    await socket.connect();
+
+    this.node.ns.server.server.emit("connection", remoteSocket);
+
+    return socket;
+  }
+}
diff --git a/src/index.ts b/src/index.ts
index a97946c..c00926a 100644
--- a/src/index.ts
+++ b/src/index.ts
@@ -12,6 +12,8 @@ import { SPVNode } from "hsd/lib/node";
 import defer from "p-defer";
 import dns from "@i2labs/dns";
 import assert from "assert";
+import { wire } from "bns";
+import TCPClient from "./dns/tcpClient.js";
 
 const PROTOCOL = "lumeweb.proxy.handshake";
 const TYPES = ["blockchain"];
@@ -29,6 +31,7 @@ addHandler("status", handleStatus, { receiveUpdates: true });
 addHandler("name", handleName);
 addHandler("ready", handleReady);
 addHandler("query", handleQuery);
+addHandler("dnsQuery", handleDnsQuery);
 
 let swarm;
 let proxy: MultiSocketProxy;
@@ -75,7 +78,6 @@ async function handlePresentKey(aq: ActiveQuery) {
     config: false,
     argv: false,
     env: false,
-    noDns: true,
     memory: false,
     logFile: false,
     logConsole: true,
@@ -143,6 +145,10 @@ async function handlePresentKey(aq: ActiveQuery) {
     node.http.http.listen = (port: number, host: string, cb: Function) => cb();
   }
 
+  node.rs.hns.forceTCP = true;
+  node.rs.hns.socket = new TCPClient({ node, swarm });
+  node.rs.hns.init();
+
   proxy = new MultiSocketProxy({
     protocol: PROTOCOL,
     swarm,
@@ -196,6 +202,33 @@ async function handleQuery(aq: ActiveQuery) {
   }
 }
 
+async function handleDnsQuery(aq: ActiveQuery) {
+  if (!node.chain.synced || !node.pool.peers.head()) {
+    aq.reject("not ready");
+    return;
+  }
+
+  if (!("fqdn" in aq.callerInput)) {
+    aq.reject("fqdn required");
+    return;
+  }
+
+  if (!("type" in aq.callerInput)) {
+    aq.reject("type required");
+    return;
+  }
+
+  const msg = new wire.Message();
+  const q = new wire.Question(aq.callerInput.fqdn, aq.callerInput.type);
+  msg.question.push(q);
+
+  const ret = await node.rs.answer(msg);
+
+  aq.respond(
+    ret.collect(aq.callerInput.fqdn, wire.stringToType(aq.callerInput.type)),
+  );
+}
+
 async function handleRegister(aq: ActiveQuery) {
   await networkRegistry.registerNetwork(TYPES);