From 4d4d504d6e099268477adf07de08d691db1adc83 Mon Sep 17 00:00:00 2001
From: LouisLam <louislam@users.noreply.github.com>
Date: Tue, 10 Aug 2021 21:03:14 +0800
Subject: [PATCH] retry ping domain with ipv6, if domain is not found

---
 server/ping-lite.js   |  4 ++--
 server/util-server.js | 27 +++++++++++++++++++++------
 2 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/server/ping-lite.js b/server/ping-lite.js
index 4a8cc2419..9f350cac7 100644
--- a/server/ping-lite.js
+++ b/server/ping-lite.js
@@ -30,7 +30,7 @@ function Ping(host, options) {
 
         const defaultArgs = [ "-n", "-w", "2", "-c", "1", host ];
 
-        if (net.isIPv6(host)) {
+        if (net.isIPv6(host) || options.ipv6) {
             defaultArgs.unshift("-6");
         }
 
@@ -115,7 +115,7 @@ Ping.prototype.send = function(callback) {
         ms = stdout.match(self._regmatch); // parse out the ##ms response
         ms = (ms && ms[1]) ? Number(ms[1]) : ms;
 
-        callback(null, ms);
+        callback(null, ms, stdout);
     }
 };
 
diff --git a/server/util-server.js b/server/util-server.js
index 1baec2a0f..e52e20881 100644
--- a/server/util-server.js
+++ b/server/util-server.js
@@ -45,15 +45,30 @@ exports.tcping = function (hostname, port) {
     });
 }
 
-exports.ping = function (hostname) {
-    return new Promise((resolve, reject) => {
-        const ping = new Ping(hostname);
+exports.ping = async (hostname) => {
+    try {
+        await exports.pingAsync(hostname);
+    } catch (e) {
+        // If the host cannot be resolved, try again with ipv6
+        if (e.message.includes("service not known")) {
+            await exports.pingAsync(hostname, true);
+        } else {
+            throw e;
+        }
+    }
+}
 
-        ping.send(function (err, ms) {
+exports.pingAsync = function (hostname, ipv6 = false) {
+    return new Promise((resolve, reject) => {
+        const ping = new Ping(hostname, {
+            ipv6
+        });
+
+        ping.send(function (err, ms, stdout) {
             if (err) {
-                reject(err)
+                reject(err);
             } else if (ms === null) {
-                reject(new Error("timeout"))
+                reject(new Error(stdout))
             } else {
                 resolve(Math.round(ms))
             }