fix(ntpClient): Intercept dns lookup calls for our ntp server as well

Hypfer · Feb 9, 2021 · c7095a7 · c7095a7
1 parent 54ca606
commit c7095a7
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Showing 2 changed files with 84 additions and 36 deletions.
diff --git a/lib/DnsHack.js b/lib/DnsHack.js
@@ -16,51 +16,96 @@ const Logger = require("./Logger");
 
     I'm sorry.
  */
+class DnsHack {
+    /**
+     *
+     * @param {object} options
+     * @param {import("./Configuration")} options.config
+     */
+    constructor(options) {
+        const self = this;
 
-const realLookup = dns.lookup;
+        this.config = options.config;
+        this.hosts = {
+            mqtt: undefined,
+            ntp: undefined
+        }
 
-dns.lookup = function lookupResolveHack(hostname, options, callback) {
-    if (typeof options === "function") {
-        callback = options;
-        return realLookup(hostname, options, callback);
-    }
 
-    if (
-        Object.getOwnPropertyNames(options).length === 2 &&
-        options.family === undefined
-    ) {
-        //This sorta looks like something that might be a request from the MQTT client
-        //Time to take a look at the stacktrace to make sure
-        //Doing this after checking the previous condition saves us from creating a stacktrace
-        //on each udp send which would be horrible for the performance
-        const stack = new Error().stack;
-
-        if (stack.includes("lookupAndConnect")) { //nodejs internal function
-            Logger.trace("Intercepting dns.lookup call for", hostname);
-
-            dns.resolve4(hostname, (err, addresses) => {
-                if (err && err.code === "ENOTFOUND") {
-                    dns.resolve6(hostname, (err, addresses) => {
-                        if (err) {
+        if(dns.lookup.name === "lookupResolveHack") {
+            throw new Error("Tried to Monkey-patch dns.lookup multiple times. Aborting");
+        }
+
+        this.config.onUpdate(async (key) => {
+            if (key === "mqtt" || key === "ntpClient") {
+                this.updateHosts();
+            }
+        });
+        this.updateHosts();
+
+
+        const realLookup = dns.lookup;
+
+        dns.lookup = function lookupResolveHack(hostname, options, callback) {
+            if (typeof options === "function") {
+                callback = options;
+                return realLookup(hostname, options, callback);
+            }
+
+            if (
+                (
+                    Object.getOwnPropertyNames(options).length === 2 &&
+                    options.family === undefined
+                ) || hostname === self.hosts.mqtt || hostname === self.hosts.ntp
+            ) {
+                //This sorta looks like something that might be a request from the MQTT client
+                //Time to take a look at the stacktrace to make sure
+                //Doing this after checking the previous condition saves us from creating a stacktrace
+                //on each udp send which would be horrible for the performance
+                const stack = new Error().stack;
+
+                if (
+                    stack.includes("lookupAndConnect") || //nodejs internal function
+                    hostname === self.hosts.mqtt || hostname === self.hosts.ntp
+                ) {
+                    Logger.trace("Intercepting dns.lookup call for", hostname);
+
+                    dns.resolve4(hostname, (err, addresses) => {
+                        if (err && err.code === "ENOTFOUND") {
+                            dns.resolve6(hostname, (err, addresses) => {
+                                if (err) {
+                                    callback(err);
+                                } else {
+                                    callback(null, addresses[0], 6);
+                                }
+                            });
+                        } else if (err) {
                             callback(err);
                         } else {
-                            callback(null, addresses[0], 6);
+                            callback(null, addresses[0], 4);
                         }
                     });
-                } else if (err) {
-                    callback(err);
                 } else {
-                    callback(null, addresses[0], 4);
+                    return realLookup(hostname, options, callback);
                 }
-            });
-        } else {
-            return realLookup(hostname, options, callback);
-        }
-    } else {
-        return realLookup(hostname, options, callback);
+            } else {
+                return realLookup(hostname, options, callback);
+            }
+        };
+
+        dns.lookup.__promisify__ = realLookup.__promisify__;
     }
-};
 
-dns.lookup.__promisify__ = realLookup.__promisify__;
+    /**
+     * @private
+     */
+    updateHosts() {
+        const mqttConfig = this.config.get("mqtt");
+        const ntpConfig = this.config.get("ntpClient");
+
+        this.hosts.mqtt = mqttConfig.server;
+        this.hosts.ntp = ntpConfig.server;
+    }
+}
 
-module.exports = null;
+module.exports = DnsHack;
diff --git a/lib/Valetudo.js b/lib/Valetudo.js
@@ -3,6 +3,7 @@ const NTPClient = require("./NTPClient");
 const Webserver = require("./webserver/WebServer");
 const MqttClient = require("./mqtt/MqttClient");
 const Configuration = require("./Configuration");
+const DnsHack = require("./DnsHack");
 const Logger = require("./Logger");
 const Tools = require("./Tools");
 
@@ -18,6 +19,8 @@ class Valetudo {
             Logger.error("Initialising Logger: " + e);
         }
 
+        this.dnsHack = new DnsHack({config: this.config});
+
         try {
             const robotImplementation = ValetudoRobotFactory.getRobotImplementation(this.config);