From e0e35ccb15a598e9a136cc179a5485e4237d2653 Mon Sep 17 00:00:00 2001
From: ForestL <45709305+ForestL18@users.noreply.github.com>
Date: Sun, 18 Aug 2024 12:19:11 +0800
Subject: [PATCH 1/2] Update system_windows.go

---
 dns/system_windows.go | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/dns/system_windows.go b/dns/system_windows.go
index 47c1ebaa4e..c87a37b19d 100644
--- a/dns/system_windows.go
+++ b/dns/system_windows.go
@@ -16,6 +16,9 @@ func dnsReadConfig() (servers []string, err error) {
 	if err != nil {
 		return
 	}
+
+	seenIPs := make(map[string]bool)
+
 	for _, aa := range aas {
 		for dns := aa.FirstDnsServerAddress; dns != nil; dns = dns.Next {
 			sa, err := dns.Address.Sockaddr.Sockaddr()
@@ -40,7 +43,12 @@ func dnsReadConfig() (servers []string, err error) {
 				// Unexpected type.
 				continue
 			}
-			servers = append(servers, ip.String())
+			
+			ipStr := ip.String()
+            if !seenIPs[ipStr] {
+                seenIPs[ipStr] = true
+                servers = append(servers, ipStr)
+            }
 		}
 	}
 	return

From 95725c121e23fa76c83d3bd93c0c858137c2be7c Mon Sep 17 00:00:00 2001
From: ForestL <45709305+ForestL18@users.noreply.github.com>
Date: Sun, 18 Aug 2024 12:55:00 +0800
Subject: [PATCH 2/2] Using map[string]struct{} as a set to store unique values

---
 dns/system_windows.go | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/dns/system_windows.go b/dns/system_windows.go
index c87a37b19d..28be405d1a 100644
--- a/dns/system_windows.go
+++ b/dns/system_windows.go
@@ -17,7 +17,7 @@ func dnsReadConfig() (servers []string, err error) {
 		return
 	}
 
-	seenIPs := make(map[string]bool)
+	uniqueIPs := make(map[string]struct{})
 
 	for _, aa := range aas {
 		for dns := aa.FirstDnsServerAddress; dns != nil; dns = dns.Next {
@@ -44,13 +44,15 @@ func dnsReadConfig() (servers []string, err error) {
 				continue
 			}
 			
-			ipStr := ip.String()
-            if !seenIPs[ipStr] {
-                seenIPs[ipStr] = true
-                servers = append(servers, ipStr)
-            }
+			uniqueIPs[ip.String()] = struct{}{}
 		}
 	}
+	
+    servers = make([]string, 0, len(uniqueIPs))
+    for ip := range uniqueIPs {
+        servers = append(servers, ip)
+    }
+
 	return
 }