[PATCH network] sdn: vxlan: always set local tunnel IP

[PATCH network] sdn: vxlan: always set local tunnel IP

[Gabriel Goller]

Frr 10.6 changed the evpn advertise-all-vni handling and no longer
falls back to the BGP router-id to derive the local vtep address for
vxlan interfaces without an explicit local tunnel IP.

This breaks setups where an evpn controller is used together with a
vxlan zone to get plain L2VNIs. In that setup, the vxlan zone creates
the linux vxlan devices, while the evpn controller advertises them
via frr's advertise-all-vni. Without a local vxlan tunnel IP on the
interface, frr 10.6 cannot reliably determine the local vtep address and
the VNI is not advertised/handled correctly.

Explicitly emit the ifupdown2 `vxlan-local-tunnelip` stanza for vxlan
zones, using the local peer/fabric underlay address that is already
determined while generating the zone configuration. Fail generation if
no local tunnel IP can be determined, since generating such an interface
would result in a broken evpn/vxlan setup with current frr.

evpn zones already emit `vxlan-local-tunnelip` for their vxlan devices
when the local vtep address is known.

Fixes: #7766.
Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---
 src/PVE/Network/SDN/Zones/VxlanPlugin.pm                   | 4 ++++
 src/test/zones/vxlan/basic/expected_sdn_interfaces         | 1 +
 src/test/zones/vxlan/ipv6/expected_sdn_interfaces          | 1 +
 src/test/zones/vxlan/vlanawarevnet/expected_sdn_interfaces | 1 +
 src/test/zones/vxlan/vxlanport/expected_sdn_interfaces     | 1 +
 5 files changed, 8 insertions(+)

diff --git a/src/PVE/Network/SDN/Zones/VxlanPlugin.pm b/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
index a40826153d9c..b1bd56db6ea9 100644
--- a/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
+++ b/src/PVE/Network/SDN/Zones/VxlanPlugin.pm
@@ -117,6 +117,9 @@ sub generate_sdn_config {
         die "neither peers nor fabric configured for VXLAN zone $plugin_config->{id}";
     }
 
+    die "could not determine local tunnel IP for VXLAN zone $zoneid"
+        if !$ifaceip;
+
     my $mtu = 1450;
     if ($iface) {
         $mtu = $interfaces_config->{$iface}->{mtu} - 50 if $interfaces_config->{$iface}->{mtu};
@@ -126,6 +129,7 @@ sub generate_sdn_config {
     #vxlan interface
     my @iface_config = ();
     push @iface_config, "vxlan-id $tag";
+    push @iface_config, "vxlan-local-tunnelip $ifaceip";
 
     for my $address (sort @peers) {
         next if $address eq $ifaceip;
diff --git a/src/test/zones/vxlan/basic/expected_sdn_interfaces b/src/test/zones/vxlan/basic/expected_sdn_interfaces
index 7b73c3e3ca60..ed6869dfa9e6 100644
--- a/src/test/zones/vxlan/basic/expected_sdn_interfaces
+++ b/src/test/zones/vxlan/basic/expected_sdn_interfaces
@@ -10,6 +10,7 @@ iface myvnet
 auto vxlan_myvnet
 iface vxlan_myvnet
 	vxlan-id 100
+	vxlan-local-tunnelip 192.168.0.1
 	vxlan_remoteip 192.168.0.2
 	vxlan_remoteip 192.168.0.3
 	mtu 1450
diff --git a/src/test/zones/vxlan/ipv6/expected_sdn_interfaces b/src/test/zones/vxlan/ipv6/expected_sdn_interfaces
index 032ab991826c..14354f61f923 100644
--- a/src/test/zones/vxlan/ipv6/expected_sdn_interfaces
+++ b/src/test/zones/vxlan/ipv6/expected_sdn_interfaces
@@ -10,6 +10,7 @@ iface myvnet
 auto vxlan_myvnet
 iface vxlan_myvnet
 	vxlan-id 100
+	vxlan-local-tunnelip 2a08:2200:100:1::10
 	vxlan_remoteip 2a08:2200:100:1::11
 	vxlan_remoteip 2a08:2200:100:1::12
 	mtu 1450
diff --git a/src/test/zones/vxlan/vlanawarevnet/expected_sdn_interfaces b/src/test/zones/vxlan/vlanawarevnet/expected_sdn_interfaces
index 55cdf9cb8887..e6331d2e3807 100644
--- a/src/test/zones/vxlan/vlanawarevnet/expected_sdn_interfaces
+++ b/src/test/zones/vxlan/vlanawarevnet/expected_sdn_interfaces
@@ -12,6 +12,7 @@ iface myvnet
 auto vxlan_myvnet
 iface vxlan_myvnet
 	vxlan-id 100
+	vxlan-local-tunnelip 192.168.0.1
 	vxlan_remoteip 192.168.0.2
 	vxlan_remoteip 192.168.0.3
 	mtu 1450
diff --git a/src/test/zones/vxlan/vxlanport/expected_sdn_interfaces b/src/test/zones/vxlan/vxlanport/expected_sdn_interfaces
index 572550a438e7..a3147b66a9c1 100644
--- a/src/test/zones/vxlan/vxlanport/expected_sdn_interfaces
+++ b/src/test/zones/vxlan/vxlanport/expected_sdn_interfaces
@@ -10,6 +10,7 @@ iface myvnet
 auto vxlan_myvnet
 iface vxlan_myvnet
 	vxlan-id 100
+	vxlan-local-tunnelip 192.168.0.1
 	vxlan_remoteip 192.168.0.2
 	vxlan_remoteip 192.168.0.3
 	vxlan-port 6000
-- 
2.47.3

Re: [PATCH network] sdn: vxlan: always set local tunnel IP

[Gabriel Goller]

Hmm maybe we could also fix this in FRR as this was not a 100% intended change.
I'll think about it and talk with Stefan when he's back.