From f11d455d5a11153444c89cf9e45bff175a43dc2f Mon Sep 17 00:00:00 2001
From: CanbiZ <47820557+MickLesk@users.noreply.github.com>
Date: Tue, 23 Sep 2025 12:54:12 +0200
Subject: [PATCH] Improve network string construction in build_container

Refactored the build_container function to handle MAC, gateway, VLAN, and MTU parameters more robustly, allowing for both direct and preformatted input. This change ensures correct formatting and prevents duplicate parameter prefixes in the network string.
---
 misc/build.func | 40 ++++++++++++++++++++++++++++++++++++----
 1 file changed, 36 insertions(+), 4 deletions(-)

diff --git a/misc/build.func b/misc/build.func
index d6b0af72..d0df26b3 100644
--- a/misc/build.func
+++ b/misc/build.func
@@ -2109,11 +2109,43 @@ build_container() {
   #  if [ "$VERBOSE" == "yes" ]; then set -x; fi
 
   NET_STRING="-net0 name=eth0,bridge=${BRG:-vmbr0}"
-  NET_STRING+="${MAC:+,hwaddr=$MAC}"
+
+  # MAC
+  if [[ -n "$MAC" ]]; then
+    case "$MAC" in
+    ,hwaddr=*) NET_STRING+="$MAC" ;;
+    *) NET_STRING+=",hwaddr=$MAC" ;;
+    esac
+  fi
+
+  # IP (immer zwingend, Standard dhcp)
   NET_STRING+=",ip=${NET:-dhcp}"
-  NET_STRING+="${GATE:+,gw=$GATE}"
-  NET_STRING+="${VLAN:+,tag=$VLAN}"
-  NET_STRING+="${MTU:+,mtu=$MTU}"
+
+  # Gateway
+  if [[ -n "$GATE" ]]; then
+    case "$GATE" in
+    ,gw=*) NET_STRING+="$GATE" ;;
+    *) NET_STRING+=",gw=$GATE" ;;
+    esac
+  fi
+
+  # VLAN
+  if [[ -n "$VLAN" ]]; then
+    case "$VLAN" in
+    ,tag=*) NET_STRING+="$VLAN" ;;
+    *) NET_STRING+=",tag=$VLAN" ;;
+    esac
+  fi
+
+  # MTU
+  if [[ -n "$MTU" ]]; then
+    case "$MTU" in
+    ,mtu=*) NET_STRING+="$MTU" ;;
+    *) NET_STRING+=",mtu=$MTU" ;;
+    esac
+  fi
+
+  # IPv6 Handling
   case "$IPV6_METHOD" in
   auto) NET_STRING="$NET_STRING,ip6=auto" ;;
   dhcp) NET_STRING="$NET_STRING,ip6=dhcp" ;;