ethernet: T6306: add support for EVPN MH uplink/core tracking

When all the underlay links go down the PE no longer has access to the VxLAN
+overlay.

To prevent blackholing of traffic the server/ES links are protodowned on the PE.
A link can be setup for uplink tracking via the following configuration:

set interfaces ethernet eth0 evpn uplink

interface-definitions/include/interface/evpn-mh-uplink.xml.i

@@ -0,0 +1,8 @@
+<!-- include start from interface/evpn-mh-uplink.xml.i -->
+<leafNode name="uplink">
+  <properties>
+    <help>Uplink to the VXLAN core</help>
+    <valueless/>
+  </properties>
+</leafNode>
+<!-- include end -->

interface-definitions/interfaces_bonding.xml.in

@@ -102,12 +102,7 @@
                   </constraint>
                 </properties>
               </leafNode>
-              <leafNode name="uplink">
-                <properties>
-                  <help>Uplink to the VXLAN core</help>
-                  <valueless/>
-                </properties>
-              </leafNode>
+              #include <include/interface/evpn-mh-uplink.xml.i>
             </children>
           </node>
           <leafNode name="hash-policy">

interface-definitions/interfaces_ethernet.xml.in

@@ -57,6 +57,14 @@
             <defaultValue>auto</defaultValue>
           </leafNode>
           #include <include/interface/eapol.xml.i>
+          <node name="evpn">
+            <properties>
+              <help>EVPN Multihoming</help>
+            </properties>
+            <children>
+              #include <include/interface/evpn-mh-uplink.xml.i>
+            </children>
+          </node>
           #include <include/interface/hw-id.xml.i>
           #include <include/interface/ipv4-options.xml.i>
           #include <include/interface/ipv6-options.xml.i>

smoketest/scripts/cli/test_interfaces_ethernet.py

@@ -354,5 +354,15 @@ def test_ethtool_flow_control(self):
                 out = loads(out)
                 self.assertFalse(out[0]['autonegotiate'])
 
+    def test_ethtool_evpn_uplink_tarcking(self):
+        for interface in self._interfaces:
+            self.cli_set(self._base_path + [interface, 'evpn', 'uplink'])
+
+        self.cli_commit()
+
+        for interface in self._interfaces:
+            frrconfig = self.getFRRconfig(f'interface {interface}', daemon='zebra')
+            self.assertIn(f' evpn mh uplink', frrconfig)
+
 if __name__ == '__main__':
     unittest.main(verbosity=2)

src/conf_mode/interfaces_ethernet.py

@@ -41,13 +41,15 @@
 from vyos.pki import load_certificate
 from vyos.pki import wrap_private_key
 from vyos.template import render
+from vyos.template import render_to_string
 from vyos.utils.process import call
 from vyos.utils.dict import dict_search
 from vyos.utils.dict import dict_to_paths_values
 from vyos.utils.dict import dict_set
 from vyos.utils.dict import dict_delete
 from vyos.utils.file import write_file
 from vyos import ConfigError
+from vyos import frr
 from vyos import airbag
 airbag.enable()
 
@@ -389,6 +391,10 @@ def generate(ethernet):
 
             write_file(ca_cert_file_path, '\n'.join(ca_chains))
 
+    ethernet['frr_zebra_config'] = ''
+    if 'deleted' not in ethernet:
+        ethernet['frr_zebra_config'] = render_to_string('frr/evpn.mh.frr.j2', ethernet)
+
     return None
 
 def apply(ethernet):
@@ -407,6 +413,17 @@ def apply(ethernet):
 
     call(f'systemctl {eapol_action} wpa_supplicant-wired@{ifname}')
 
+    zebra_daemon = 'zebra'
+    # Save original configuration prior to starting any commit actions
+    frr_cfg = frr.FRRConfig()
+
+    # The route-map used for the FIB (zebra) is part of the zebra daemon
+    frr_cfg.load_configuration(zebra_daemon)
+    frr_cfg.modify_section(f'^interface {ifname}', stop_pattern='^exit', remove_stop_mark=True)
+    if 'frr_zebra_config' in ethernet:
+        frr_cfg.add_before(frr.default_add_before, ethernet['frr_zebra_config'])
+    frr_cfg.commit_configuration(zebra_daemon)
+
 if __name__ == '__main__':
     try:
         c = get_config()