From 3bcdae70f742771a4e71e7029009778935d86362 Mon Sep 17 00:00:00 2001
From: Monviech <79600909+Monviech@users.noreply.github.com>
Date: Sun, 1 Feb 2026 13:23:36 +0100
Subject: [PATCH] radvd: When Base6Interface constructor is used, use its
 primary address for ifcfgipv6 (#9689)

---
 src/etc/inc/plugins.inc.d/radvd.inc | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/etc/inc/plugins.inc.d/radvd.inc b/src/etc/inc/plugins.inc.d/radvd.inc
index fbe3f7b138..3477241ef4 100644
--- a/src/etc/inc/plugins.inc.d/radvd.inc
+++ b/src/etc/inc/plugins.inc.d/radvd.inc
@@ -149,8 +149,16 @@ function radvd_configure_do($verbose = false, $ignorelist = [])
 
         $carp_mode = false;
         $src_addr = false;
+        $ifcfgipv6 = null;
+
+        if (!$entry->AdvRASrcAddress->isEmpty()) {
+            $ifcfgipv6 = $entry->AdvRASrcAddress->getValue();
+        } elseif (!$entry->Base6Interface->isEmpty()) {
+            $ifcfgipv6 = get_interface_ipv6($entry->Base6Interface->getValue());
+        } else {
+            $ifcfgipv6 = get_interface_ipv6($dhcpv6if);
+        }
 
-        $ifcfgipv6 = !$entry->AdvRASrcAddress->isEmpty() ? $entry->AdvRASrcAddress->getValue() : get_interface_ipv6($dhcpv6if);
         if (!is_ipaddrv6($ifcfgipv6)) {
             $radvdconf .= "# Skipping addressless interface {$dhcpv6if}\n";
             continue;