From 9f4a04152f3a412db00e511027916312573db50d Mon Sep 17 00:00:00 2001
From: Guillem Bonet <guillem.bonet@gmail.com>
Date: Mon, 13 Feb 2023 15:44:34 +0100
Subject: [PATCH] allow fetching public IP instead of using defined host

Signed-off-by: Guillem Bonet <guillem.bonet@gmail.com>
---
 Dockerfile           |  4 ++--
 README.md            |  1 +
 src/config.js        |  1 +
 src/lib/WireGuard.js | 17 ++++++++++++++---
 4 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 2695361f..2a8e735f 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -9,7 +9,7 @@
 # #
 # #
 
-FROM docker.io/library/node:14-alpine@sha256:dc92f36e7cd917816fa2df041d4e9081453366381a00f40398d99e9392e78664 AS build_node_modules
+FROM docker.io/library/node:18-alpine AS build_node_modules
 
 # Copy Web UI
 COPY src/ /app/
@@ -18,7 +18,7 @@ RUN npm ci --production
 
 # Copy build result to a new image.
 # This saves a lot of disk space.
-FROM docker.io/library/node:14-alpine@sha256:dc92f36e7cd917816fa2df041d4e9081453366381a00f40398d99e9392e78664
+FROM docker.io/library/node:18-alpine
 COPY --from=build_node_modules /app /app
 
 # Move node_modules one directory up, so during development
diff --git a/README.md b/README.md
index 6daca1b2..f04d62e3 100644
--- a/README.md
+++ b/README.md
@@ -83,6 +83,7 @@ These options can be configured by setting environment variables using `-e KEY="
 | - | - | - | - |
 | `PASSWORD` | - | `foobar123` | When set, requires a password when logging in to the Web UI. |
 | `WG_HOST` | - | `vpn.myserver.com` | The public hostname of your VPN server. |
+| `IPIFY_URL` | - | `https://api.ipify.org?format=json` | API to fetch our public IP. |
 | `WG_PORT` | `51820` | `12345` | The public UDP port of your VPN server. WireGuard will always listen on `51820` inside the Docker container. |
 | `WG_MTU` | `null` | `1420` | The MTU the clients will use. Server uses default WG MTU. |
 | `WG_PERSISTENT_KEEPALIVE` | `0` | `25` | Value in seconds to keep the "connection" open. If this value is 0, then connections won't be kept alive. |
diff --git a/src/config.js b/src/config.js
index 28c9fc5a..f68c5120 100644
--- a/src/config.js
+++ b/src/config.js
@@ -7,6 +7,7 @@ module.exports.PORT = process.env.PORT || 51821;
 module.exports.PASSWORD = process.env.PASSWORD;
 module.exports.WG_PATH = process.env.WG_PATH || '/etc/wireguard/';
 module.exports.WG_HOST = process.env.WG_HOST;
+module.exports.IPIFY_URL = process.env.IPIFY_URL;
 module.exports.WG_PORT = process.env.WG_PORT || 51820;
 module.exports.WG_MTU = process.env.WG_MTU || null;
 module.exports.WG_PERSISTENT_KEEPALIVE = process.env.WG_PERSISTENT_KEEPALIVE || 0;
diff --git a/src/lib/WireGuard.js b/src/lib/WireGuard.js
index 7886ac91..2f29a88a 100644
--- a/src/lib/WireGuard.js
+++ b/src/lib/WireGuard.js
@@ -13,6 +13,7 @@ const ServerError = require('./ServerError');
 const {
   WG_PATH,
   WG_HOST,
+  IPIFY_URL,
   WG_PORT,
   WG_MTU,
   WG_DEFAULT_DNS,
@@ -30,8 +31,8 @@ module.exports = class WireGuard {
   async getConfig() {
     if (!this.__configPromise) {
       this.__configPromise = Promise.resolve().then(async () => {
-        if (!WG_HOST) {
-          throw new Error('WG_HOST Environment Variable Not Set!');
+        if (!WG_HOST && !IPIFY_URL) {
+          throw new Error('WG_HOST or IPIFY_URL Environment Variable Not Set!');
         }
 
         debug('Loading configuration...');
@@ -192,9 +193,19 @@ AllowedIPs = ${client.address}/32`;
     return client;
   }
 
+  async getPublicIp() {
+    if (IPIFY_URL == "") {
+      return WG_HOST
+    }
+    const response = await fetch(IPIFY_URL);
+    const data = await response.json();
+    return data.ip;
+  }
+
   async getClientConfiguration({ clientId }) {
     const config = await this.getConfig();
     const client = await this.getClient({ clientId });
+    const host = await this.getPublicIp();
 
     return `
 [Interface]
@@ -208,7 +219,7 @@ PublicKey = ${config.server.publicKey}
 PresharedKey = ${client.preSharedKey}
 AllowedIPs = ${WG_ALLOWED_IPS}
 PersistentKeepalive = ${WG_PERSISTENT_KEEPALIVE}
-Endpoint = ${WG_HOST}:${WG_PORT}`;
+Endpoint = ${host}:${WG_PORT}`;
   }
 
   async getClientQRCodeSVG({ clientId }) {