From e860d3b974513956c562d0eb34aef0ea120c6b06 Mon Sep 17 00:00:00 2001
From: bt90 <btom1990@googlemail.com>
Date: Tue, 12 Sep 2023 14:34:30 +0200
Subject: [PATCH] lib/connections: Make assumptions about isLAN when interface
 address listing fails (#9093)

---
 lib/connections/service.go | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/lib/connections/service.go b/lib/connections/service.go
index 23968fc80..c08a47c95 100644
--- a/lib/connections/service.go
+++ b/lib/connections/service.go
@@ -782,6 +782,10 @@ func (s *lanChecker) isLAN(addr net.Addr) bool {
 		return true
 	}
 
+	if ip.IsLinkLocalUnicast() {
+		return true
+	}
+
 	for _, lan := range s.cfg.Options().AlwaysLocalNets {
 		_, ipnet, err := net.ParseCIDR(lan)
 		if err != nil {
@@ -793,7 +797,14 @@ func (s *lanChecker) isLAN(addr net.Addr) bool {
 		}
 	}
 
-	lans, _ := osutil.GetLans()
+	lans, err := osutil.GetLans()
+	if err != nil {
+		l.Debugln("Failed to retrieve interface IPs:", err)
+		priv := ip.IsPrivate()
+		l.Debugf("Assuming isLAN=%v for IP %v", priv, ip)
+		return priv
+	}
+
 	for _, lan := range lans {
 		if lan.Contains(ip) {
 			return true