vpp: T8125: Enable ip4-dhcp-client-detect feature if interface address is configured as DHCP

DHCP address cannot be assigned on VPP interfaces without enabling the 'ip4-dhcp-client-detect' feature

4 files changed, 62 insertions, 10 deletions

diff --git a/data/templates/vpp/startup.conf.j2 b/data/templates/vpp/startup.conf.j2
index b67251acc..b5b4853ce 100644
--- a/data/templates/vpp/startup.conf.j2
+++ b/data/templates/vpp/startup.conf.j2
@@ -114,6 +114,8 @@ plugins {
     # plugin wireguard_plugin.so { enable }
     # ACL
     plugin acl_plugin.so { enable }
+    # DHCP plugin
+    plugin dhcp_plugin.so { enable }
 }
 
 
diff --git a/python/vyos/vpp/control_vpp.py b/python/vyos/vpp/control_vpp.py
index 2ee253b45..18ec349bc 100644
--- a/python/vyos/vpp/control_vpp.py
+++ b/python/vyos/vpp/control_vpp.py
@@ -494,3 +494,34 @@ class VPPControl:
                 cp_sw_if_index=self.get_sw_if_index(vpp_pair_name),
                 is_add=is_add,
             )
+
+    @_Decorators.api_call
+    def enable_dhcp_client(self, ifname: str) -> None:
+        """Enable DHCP client detection on a given interface
+
+        Args:
+            ifname (str): name of an interface in kernel
+        """
+        iface_index = self.get_sw_if_index(ifname)
+        feature_is_enabled = self.__vpp_api_client.api.feature_is_enabled(
+            sw_if_index=iface_index,
+            feature_name='ip4-dhcp-client-detect',
+            arc_name='ip4-unicast',
+        )
+        if not feature_is_enabled.is_enabled:
+            self.__vpp_api_client.api.dhcp_client_detect_enable_disable(
+                sw_if_index=iface_index,
+                enable=True,
+            )
+
+    @_Decorators.api_call
+    def disable_dhcp_client(self, ifname: str) -> None:
+        """Disable DHCP client detection on a given interface
+
+        Args:
+            ifname (str): name of an interface in kernel
+        """
+        self.__vpp_api_client.api.dhcp_client_detect_enable_disable(
+            sw_if_index=self.get_sw_if_index(ifname),
+            enable=False,
+        )
diff --git a/smoketest/scripts/cli/test_vpp.py b/smoketest/scripts/cli/test_vpp.py
index 1886ac615..b985a45d4 100755
--- a/smoketest/scripts/cli/test_vpp.py
+++ b/smoketest/scripts/cli/test_vpp.py
@@ -139,6 +139,7 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
             'plugin default { disable }',
             'plugin dpdk_plugin.so { enable }',
             'plugin linux_cp_plugin.so { enable }',
+            'plugin dhcp_plugin.so { enable }',
             'dev 0000:00:00.0',
             'uio-bind-force',
         )
@@ -175,6 +176,14 @@ class TestVPP(VyOSUnitTestSHIM.TestCase):
         self.cli_delete(['interfaces', 'ethernet', interface, 'mtu'])
         self.cli_commit()
 
+        # set interface address as dhcp
+        self.cli_set(['interfaces', 'ethernet', interface, 'address', 'dhcp'])
+        self.cli_commit()
+
+        # check 'ip4-dhcp-client-detect' feature is enabled on interface
+        _, out = rc_cmd(f'sudo vppctl show interface features {interface}')
+        self.assertIn(f'ip4-dhcp-client-detect', out)
+
     def test_02_vpp_vxlan(self):
         vni = '23'
         interface_vxlan = f'vxlan{vni}'
diff --git a/src/conf_mode/interfaces_ethernet.py b/src/conf_mode/interfaces_ethernet.py
index 599421c72..ffb59c89e 100755
--- a/src/conf_mode/interfaces_ethernet.py
+++ b/src/conf_mode/interfaces_ethernet.py
@@ -447,17 +447,27 @@ def apply(ethernet):
     if 'static_arp' in ethernet:
         call_dependents()
 
-    # If the interface is managed by the VPP DPDK driver, synchronize runtime
-    # parameters between Linux and the corresponding VPP LCP interface
-    if dict_search(f'vpp.settings.interface.{ifname}.driver', ethernet) == 'dpdk':
+    vpp_iface_config = dict_search(f'vpp.settings.interface.{ifname}', ethernet)
+    if vpp_iface_config and is_systemd_service_running('vpp.service'):
         vpp_api = VPPControl()
-        # Find LCP pair
-        lcp_pair = vpp_api.lcp_pair_find(vpp_name_hw=ifname)
-        lcp_name = lcp_pair.get('vpp_name_kernel')
-        # Sync MTU to VPP LCP pair interface
-        if lcp_name:
-            mtu = e.get_mtu()
-            vpp_api.set_iface_mtu(lcp_name, mtu)
+
+        # Enable ip4-dhcp-client-detect feature for DHCP-configured interfaces.
+        # This feature is required for VPP to process DHCP packets and assign addresses.
+        if 'dhcp' in ethernet.get('address', []):
+            vpp_api.enable_dhcp_client(ifname)
+        else:
+            vpp_api.disable_dhcp_client(ifname)
+
+        # If the interface is managed by the VPP DPDK driver, synchronize runtime
+        # parameters between Linux and the corresponding VPP LCP interface
+        if vpp_iface_config.get('driver') == 'dpdk':
+            # Find LCP pair
+            lcp_pair = vpp_api.lcp_pair_find(vpp_name_hw=ifname)
+            lcp_name = lcp_pair.get('vpp_name_kernel')
+            # Sync MTU to VPP LCP pair interface
+            if lcp_name:
+                mtu = e.get_mtu()
+                vpp_api.set_iface_mtu(lcp_name, mtu)
 
     return None