[PATCH ifupdown2] d/patches: don't fail vxlan syntax check on missing local tunnelip

[Gabriel Goller <g.goller@proxmox.com>]

Don't fail the syntax check when no vxlan-local-tunnelip is configured.
This is fine, the local tunnelip can be retrieved from somewhere else.
Check the patch description for more info.

We don't usually run `ifreload -s`, so the syntax check won't be run on
a normal apply.

Motivation: https://lore.proxmox.com/pve-devel/aqEkLo5GMnrhZoJF@luna.proxmox.com/

Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---
 ...-t-fail-syntax-check-on-missing-vxla.patch | 39 +++++++++++++++++++
 debian/patches/series                         |  1 +
 2 files changed, 40 insertions(+)
 create mode 100644 debian/patches/pve/0016-addons-vxlan-don-t-fail-syntax-check-on-missing-vxla.patch

diff --git a/debian/patches/pve/0016-addons-vxlan-don-t-fail-syntax-check-on-missing-vxla.patch b/debian/patches/pve/0016-addons-vxlan-don-t-fail-syntax-check-on-missing-vxla.patch
new file mode 100644
index 000000000000..9fab80d662bb
--- /dev/null
+++ b/debian/patches/pve/0016-addons-vxlan-don-t-fail-syntax-check-on-missing-vxla.patch
@@ -0,0 +1,39 @@
+From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
+From: Gabriel Goller <g.goller@proxmox.com>
+Date: Sun, 14 Sep 2026 12:00:00 +0200
+Subject: [PATCH] addons: vxlan: don't fail syntax check on missing
+ vxlan-local-tunnelip
+
+vxlan-local-tunnelip is declared optional, both in the module's attribute
+description and in the generated man page. Without it the kernel picks
+the source address from the route to the remote endpoint, which is what
+we want for setups that use vxlan-physdev or a multicast group. The
+check is a Cumulus-ism that assumes every vxlan is anchored on a loopback
+address.
+
+The warning also made this whole check return False, so `ifup --syntax-check`
+failed for a perfectly valid configuration.
+
+The early return also skipped check_and_raise_svd_tvd_errors(), so a real
+single-vxlan/traditional-vxlan mixing error was suppressed until the interface
+was actually brought up. Removing the block restores that check for devices
+without a local tunnel ip.
+
+Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
+---
+ ifupdown2/addons/vxlan.py |    4 ----
+ 1 file changed, 4 deletions(-)
+
+--- a/ifupdown2/addons/vxlan.py
++++ b/ifupdown2/addons/vxlan.py
+@@ -191,10 +191,6 @@
+ 
+     def syntax_check(self, ifaceobj, ifaceobj_getfunc):
+         if self._is_vxlan_device(ifaceobj):
+-            if not ifaceobj.get_attr_value_first('vxlan-local-tunnelip') and not self._vxlan_local_tunnelip:
+-                self.logger.warning('%s: missing vxlan-local-tunnelip' % ifaceobj.name)
+-                return False
+-
+             self.check_and_raise_svd_tvd_errors(ifaceobj)
+ 
+             return self.syntax_check_localip_anycastip_equal(
diff --git a/debian/patches/series b/debian/patches/series
index 2865533271c9..0eec1531762a 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -16,3 +16,4 @@ upstream/0001-use-raw-strings-for-regex-to-fix-backslash-interpret.patch
 upstream/0002-vxlan-add-support-for-IPv6-vxlan-local-tunnelip.patch
 pve/0014-nlmanager-read-ipv6-devconf-disable_ipv6-attribute-t.patch
 pve/0015-revert-addons-bond-warn-if-sub-interface-is-detected-on-bond-slave.patch
+pve/0016-addons-vxlan-don-t-fail-syntax-check-on-missing-vxla.patch
-- 
2.47.3