vxlan: T3700: support VLAN tunnel mapping of VLAN aware bridges

FRR supports a new way of configuring VLAN-to-VNI mappings for EVPN-VXLAN, when
working with the Linux kernel. In this new way, the mapping of a VLAN to a VNI
is configured against a container VXLAN interface which is referred to as a
'Single VXLAN device (SVD)'.

Multiple VLAN to VNI mappings can be configured against the same SVD. This
allows for a significant scaling of the number of VNIs since a separate VXLAN
interface is no longer required for each VNI.

Sample configuration of SVD with VLAN to VNI mappings is shown below.

set interfaces bridge br0 member interface vxlan0
set interfaces vxlan vxlan0 external
set interfaces vxlan vxlan0 source-interface 'dum0'
set interfaces vxlan vxlan0 vlan-to-vni 10 vni '10010'
set interfaces vxlan vxlan0 vlan-to-vni 11 vni '10011'
set interfaces vxlan vxlan0 vlan-to-vni 30 vni '10030'
set interfaces vxlan vxlan0 vlan-to-vni 31 vni '10031'

1 files changed, 19 insertions, 1 deletions

diff --git a/src/conf_mode/interfaces-vxlan.py b/src/conf_mode/interfaces-vxlan.py
index a3b0867e0..05f68112a 100755
--- a/src/conf_mode/interfaces-vxlan.py
+++ b/src/conf_mode/interfaces-vxlan.py
@@ -1,6 +1,6 @@
 #!/usr/bin/env python3
 #
-# Copyright (C) 2019-2022 VyOS maintainers and contributors
+# Copyright (C) 2019-2023 VyOS maintainers and contributors
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 2 or later as
@@ -24,6 +24,7 @@ from vyos.config import Config
 from vyos.configdict import get_interface_dict
 from vyos.configdict import leaf_node_changed
 from vyos.configdict import is_node_changed
+from vyos.configdict import node_changed
 from vyos.configverify import verify_address
 from vyos.configverify import verify_bridge_delete
 from vyos.configverify import verify_mtu_ipv6
@@ -58,6 +59,9 @@ def get_config(config=None):
             vxlan.update({'rebuild_required': {}})
             break
 
+    tmp = node_changed(conf, base + [ifname, 'vlan-to-vni'], recursive=True)
+    if tmp: vxlan.update({'vlan_to_vni_removed': tmp})
+
     # We need to verify that no other VXLAN tunnel is configured when external
     # mode is in use - Linux Kernel limitation
     conf.set_level(base)
@@ -146,6 +150,20 @@ def verify(vxlan):
                     raise ConfigError(error_msg)
                 protocol = 'ipv4'
 
+    if 'vlan_to_vni' in vxlan:
+        if 'is_bridge_member' not in vxlan:
+            raise ConfigError('VLAN to VNI mapping requires that VXLAN interface '\
+                              'is member of a bridge interface!')
+
+        vnis_used = []
+        for vif, vif_config in vxlan['vlan_to_vni'].items():
+            if 'vni' not in vif_config:
+                raise ConfigError(f'Must define VNI for VLAN "{vif}"!')
+            vni = vif_config['vni']
+            if vni in vnis_used:
+                raise ConfigError(f'VNI "{vni}" is already assigned to a different VLAN!')
+            vnis_used.append(vni)
+
     verify_mtu_ipv6(vxlan)
     verify_address(vxlan)
     verify_bond_bridge_member(vxlan)