vlan: Default reorder-headers: true

When `reorder-headers` is not mentioned in desire state, we should
set it to true to be consistent with default behavior of kernel and
NetworkManager.

Integration test cases included.

Resolves: https://issues.redhat.com/browse/RHEL-33362

Signed-off-by: Gris Ge <fge@redhat.com>

rust/src/lib/iface.rs

@@ -814,6 +814,7 @@ impl MergedInterface {
         self.post_inter_ifaces_process_sriov()?;
         self.post_inter_ifaces_process_vrf()?;
         self.post_inter_ifaces_process_bond()?;
+        self.post_inter_ifaces_process_vlan();
 
         if let Some(apply_iface) = self.for_apply.as_mut() {
             apply_iface.sanitize(true)?;

rust/src/lib/ifaces/vlan.rs

@@ -1,6 +1,8 @@
+// SPDX-License-Identifier: Apache-2.0
+
 use serde::{Deserialize, Serialize};
 
-use crate::{BaseInterface, InterfaceType};
+use crate::{BaseInterface, Interface, InterfaceType, MergedInterface};
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
 #[non_exhaustive]
@@ -66,7 +68,7 @@ pub struct VlanConfig {
     /// Could be `gvrp`, `mvrp` or `none`. Default to none if not defined.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub registration_protocol: Option<VlanRegistrationProtocol>,
-    /// reordering of output packet headers
+    /// reordering of output packet headers. Default to True if not defined.
     #[serde(skip_serializing_if = "Option::is_none")]
     pub reorder_headers: Option<bool>,
     /// loose binding of the interface to its master device's operating state
@@ -113,3 +115,30 @@ pub enum VlanRegistrationProtocol {
     /// No Registration Protocol
     None,
 }
+
+impl MergedInterface {
+    // Default reorder_headers to Some(true) unless current interface
+    // has `reorder_headers` set to `false`
+    pub(crate) fn post_inter_ifaces_process_vlan(&mut self) {
+        if let Some(Interface::Vlan(apply_iface)) = self.for_apply.as_mut() {
+            if let Some(Interface::Vlan(cur_iface)) = self.current.as_ref() {
+                if cur_iface
+                    .vlan
+                    .as_ref()
+                    .and_then(|v| v.reorder_headers.as_ref())
+                    != Some(&false)
+                {
+                    if let Some(vlan_conf) = apply_iface.vlan.as_mut() {
+                        if vlan_conf.reorder_headers.is_none() {
+                            vlan_conf.reorder_headers = Some(true);
+                        }
+                    }
+                }
+            } else if let Some(vlan_conf) = apply_iface.vlan.as_mut() {
+                if vlan_conf.reorder_headers.is_none() {
+                    vlan_conf.reorder_headers = Some(true);
+                }
+            }
+        }
+    }
+}

tests/integration/vlan_test.py

@@ -428,3 +428,55 @@ def test_configure_vlan_with_mvrp(vlan_on_eth1):
     ] = VLAN.REGISTRATION_PROTOCOL_NONE
     libnmstate.apply(flags_state)
     assertlib.assert_state_match(flags_state)
+
+
+def test_new_vlan_default_to_reorder_headers(eth1_up):
+    with vlan_interface(VLAN_IFNAME, 102, "eth1") as desired_state:
+        desired_state[Interface.KEY][0][VLAN.CONFIG_SUBTREE][
+            VLAN.REORDER_HEADERS
+        ] = True
+        assertlib.assert_state_match(desired_state)
+    assertlib.assert_absent(VLAN_IFNAME)
+
+
+@pytest.fixture
+def vlan_on_eth1_with_reorder_headers_off(vlan_on_eth1):
+    desired_state = {
+        Interface.KEY: [
+            {
+                Interface.NAME: VLAN_IFNAME,
+                Interface.TYPE: InterfaceType.VLAN,
+                Interface.STATE: InterfaceState.UP,
+                VLAN.CONFIG_SUBTREE: {
+                    VLAN.ID: 102,
+                    VLAN.BASE_IFACE: "eth1",
+                    VLAN.REORDER_HEADERS: False,
+                },
+            }
+        ]
+    }
+    libnmstate.apply(desired_state)
+    yield
+
+
+def test_vlan_do_not_override_reorder_headers_if_not_mentioned(
+    vlan_on_eth1_with_reorder_headers_off,
+):
+    desired_state = {
+        Interface.KEY: [
+            {
+                Interface.NAME: VLAN_IFNAME,
+                Interface.TYPE: InterfaceType.VLAN,
+                Interface.STATE: InterfaceState.UP,
+                VLAN.CONFIG_SUBTREE: {
+                    VLAN.ID: 102,
+                    VLAN.BASE_IFACE: "eth1",
+                },
+            }
+        ]
+    }
+    libnmstate.apply(desired_state)
+    current_state = statelib.show_only((VLAN_IFNAME,))
+    assert not current_state[Interface.KEY][0][VLAN.CONFIG_SUBTREE][
+        VLAN.REORDER_HEADERS
+    ]