interface: implement VLAN subinterfaces configuration

Example configuration (CLI):
```
[snip]
interfaces interface eth-rt2.10
 type ietf-if-extensions:ethSubInterface
 encapsulation dot1q-vlan outer-tag vlan-id 10
 parent-interface eth-rt2
!
```

Example configuration (JSON):
```
{
  "ietf-interfaces:interfaces": {
    "interface": [
      [snip]
      {
        "name": "eth-rt2.10",
        "type": "ietf-if-extensions:ethSubInterface",
        "ietf-if-extensions:encapsulation": {
          "ietf-if-vlan-encapsulation:dot1q-vlan": {
            "outer-tag": {
              "vlan-id": 10
            }
          }
        },
        "ietf-if-extensions:parent-interface": "eth-rt2"
      }
    ]
  }
}
```

Signed-off-by: Renato Westphal <renato@opensourcerouting.org>

README.md

@@ -217,6 +217,8 @@ Holo supports the following IETF RFCs and Internet drafts:
 | ietf-bfd@2022-09-22 | 100.00% | 100.00% | - | - | [100.00%](http://westphal.com.br/holo/ietf-bfd.html) |
 | ietf-bgp-policy@2023-07-05 | 100.00% | - | - | - | [100.00%](http://westphal.com.br/holo/ietf-bgp-policy.html) |
 | ietf-bgp@2023-07-05 | 32.38% | 87.86% | - | - | [61.39%](http://westphal.com.br/holo/ietf-bgp.html) |
+| ietf-if-extensions@2023-01-26 | 100.00% | 0.00% | - | - | [50.00%](http://westphal.com.br/holo/ietf-if-extensions.html) |
+| ietf-if-vlan-encapsulation@2023-01-26 | 42.86% | - | - | - | [42.86%](http://westphal.com.br/holo/ietf-if-vlan-encapsulation.html) |
 | ietf-interfaces@2018-01-09 | 100.00% | 0.00% | - | - | [22.22%](http://westphal.com.br/holo/ietf-interfaces.html) |
 | ietf-ip@2018-01-09 | 52.17% | 0.00% | - | - | [40.00%](http://westphal.com.br/holo/ietf-ip.html) |
 | ietf-ipv4-unicast-routing@2018-03-13 | 100.00% | 100.00% | - | - | [100.00%](http://westphal.com.br/holo/ietf-ipv4-unicast-routing.html) |

holo-interface/src/interface.rs

@@ -65,6 +65,7 @@ impl Interface {
         &self,
         ifindex: u32,
         netlink_handle: &rtnetlink::Handle,
+        interfaces: &Interfaces,
     ) {
         // Set administrative status.
         netlink::admin_status_change(
@@ -74,6 +75,22 @@ impl Interface {
         )
         .await;
 
+        // Create VLAN subinterface.
+        if let Some(vlan_id) = self.config.vlan_id
+            && self.ifindex.is_none()
+            && let Some(parent) = &self.config.parent
+            && let Some(parent) = interfaces.get_by_name(parent)
+            && let Some(parent_ifindex) = parent.ifindex
+        {
+            netlink::vlan_create(
+                netlink_handle,
+                self.name.clone(),
+                parent_ifindex,
+                vlan_id,
+            )
+            .await;
+        }
+
         // Set MTU.
         if let Some(mtu) = self.config.mtu {
             netlink::mtu_change(netlink_handle, ifindex, mtu).await;
@@ -153,7 +170,9 @@ impl Interfaces {
                 // configuration options.
                 if iface.ifindex.is_none() {
                     iface.ifindex = Some(ifindex);
-                    iface.apply_config(ifindex, netlink_handle).await;
+
+                    let iface = &self.arena[iface_idx];
+                    iface.apply_config(ifindex, netlink_handle, self).await;
                 }
             }
             None => {

holo-interface/src/netlink.rs

@@ -204,6 +204,21 @@ pub(crate) async fn mtu_change(handle: &Handle, ifindex: u32, mtu: u32) {
     }
 }
 
+pub(crate) async fn vlan_create(
+    handle: &Handle,
+    name: String,
+    parent_ifindex: u32,
+    vlan_id: u16,
+) {
+    // Create netlink request.
+    let request = handle.link().add().vlan(name, parent_ifindex, vlan_id);
+
+    // Execute request.
+    if let Err(error) = request.execute().await {
+        error!(%parent_ifindex, %vlan_id, %error, "failed to create VLAN interface");
+    }
+}
+
 pub(crate) async fn addr_install(
     handle: &Handle,
     ifindex: u32,

holo-interface/src/northbound/configuration.rs

@@ -41,6 +41,7 @@ pub enum Event {
     InterfaceDelete(String),
     AdminStatusChange(String, bool),
     MtuChange(String, u32),
+    VlanCreate(String, u16),
     AddressInstall(String, IpNetwork),
     AddressUninstall(String, IpNetwork),
 }
@@ -51,6 +52,8 @@ pub enum Event {
 pub struct InterfaceCfg {
     pub enabled: bool,
     pub mtu: Option<u32>,
+    pub parent: Option<String>,
+    pub vlan_id: Option<u16>,
     pub addr_list: BTreeSet<IpNetwork>,
 }
 
@@ -96,6 +99,31 @@ fn load_callbacks() -> Callbacks<Master> {
             let event_queue = args.event_queue;
             event_queue.insert(Event::AdminStatusChange(ifname, enabled));
         })
+        .path(interfaces::interface::parent_interface::PATH)
+        .modify_apply(|master, args| {
+            let ifname = args.list_entry.into_interface().unwrap();
+            let parent = args.dnode.get_string();
+
+            let iface = master.interfaces.get_mut_by_name(&ifname).unwrap();
+            iface.config.parent = Some(parent);
+        })
+        .delete_apply(|master, args| {
+            let ifname = args.list_entry.into_interface().unwrap();
+
+            let iface = master.interfaces.get_mut_by_name(&ifname).unwrap();
+            iface.config.parent = None;
+        })
+        .path(interfaces::interface::encapsulation::dot1q_vlan::outer_tag::vlan_id::PATH)
+        .modify_apply(|master, args| {
+            let ifname = args.list_entry.into_interface().unwrap();
+            let vlan_id = args.dnode.get_u16();
+
+            let iface = master.interfaces.get_mut_by_name(&ifname).unwrap();
+            iface.config.vlan_id = Some(vlan_id);
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::VlanCreate(ifname, vlan_id));
+        })
         .path(interfaces::interface::ipv4::PATH)
         .create_apply(|_context, _args| {
             // TODO: implement me!
@@ -288,6 +316,24 @@ impl Provider for Master {
                         .await;
                 }
             }
+            Event::VlanCreate(ifname, vlan_id) => {
+                // If the parent interface is active, create VLAN subinterface
+                // using the netlink handle.
+                if let Some(iface) = self.interfaces.get_by_name(&ifname)
+                    && iface.ifindex.is_none()
+                    && let Some(parent) = &iface.config.parent
+                    && let Some(parent) = self.interfaces.get_by_name(parent)
+                    && let Some(parent_ifindex) = parent.ifindex
+                {
+                    netlink::vlan_create(
+                        &self.netlink_handle,
+                        iface.name.clone(),
+                        parent_ifindex,
+                        vlan_id,
+                    )
+                    .await;
+                }
+            }
             Event::AddressInstall(ifname, addr) => {
                 // If the interface is active, install the address using the
                 // netlink handle.
@@ -325,6 +371,8 @@ impl Default for InterfaceCfg {
         InterfaceCfg {
             enabled,
             mtu: None,
+            parent: None,
+            vlan_id: None,
             addr_list: Default::default(),
         }
     }

holo-interface/src/northbound/mod.rs

@@ -17,7 +17,12 @@ use crate::Master;
 
 impl ProviderBase for Master {
     fn yang_modules() -> &'static [&'static str] {
-        &["ietf-interfaces", "ietf-ip"]
+        &[
+            "ietf-if-extensions",
+            "ietf-if-vlan-encapsulation",
+            "ietf-interfaces",
+            "ietf-ip",
+        ]
     }
 
     fn top_level_node(&self) -> String {

holo-tools/yang-coverage.sh

@@ -2,6 +2,8 @@
 
 cargo run --bin yang_coverage --\
   -m ietf-interfaces\
+  -m ietf-if-extensions\
+  -m ietf-if-vlan-encapsulation\
   -m ietf-ip\
   -m ietf-ipv4-unicast-routing\
   -m ietf-ipv6-unicast-routing\

holo-yang/modules/deviations/ietf-if-extensions-holo-deviations.yang

@@ -0,0 +1,28 @@
+module ietf-if-extensions-holo-deviations {
+  yang-version 1.1;
+  namespace "http://holo-routing.org/yang/ietf-if-extensions-holo-deviations";
+  prefix ietf-if-extensions-holo-deviations;
+
+  import ietf-interfaces {
+    prefix if;
+  }
+
+  import ietf-if-extensions {
+    prefix if-ext;
+  }
+
+  organization
+    "Holo Routing Stack";
+
+  description
+    "This module defines deviation statements for the ietf-if-extensions
+     module.";
+
+  deviation "/if:interfaces/if:interface/if:statistics/if-ext:in-discard-unknown-encaps" {
+    deviate not-supported;
+  }
+
+  deviation "/if:interfaces/if:interface/if-ext:forwarding-mode" {
+    deviate not-supported;
+  }
+}

holo-yang/modules/deviations/ietf-if-vlan-encapsulation-holo-deviations.yang

@@ -0,0 +1,51 @@
+module ietf-if-vlan-encapsulation-holo-deviations {
+  yang-version 1.1;
+  namespace "http://holo-routing.org/yang/ietf-if-vlan-encapsulation-holo-deviations";
+  prefix ietf-if-vlan-encapsulation-holo-deviations;
+
+  import ietf-interfaces {
+    prefix if;
+  }
+
+  import ietf-if-extensions {
+    prefix if-ext;
+  }
+
+  import ietf-if-vlan-encapsulation {
+    prefix if-vlan;
+  }
+
+  organization
+    "Holo Routing Stack";
+
+  description
+    "This module defines deviation statements for the ietf-if-vlan-encapsulation
+     module.";
+
+  deviation "/if:interfaces/if:interface/if-ext:encapsulation/if-ext:encaps-type/if-vlan:dot1q-vlan/if-vlan:dot1q-vlan/if-vlan:outer-tag" {
+    deviate delete {
+      must 'tag-type = "dot1q-types:s-vlan" or '
+         + 'tag-type = "dot1q-types:c-vlan"';
+    }
+  }
+
+  deviation "/if:interfaces/if:interface/if-ext:encapsulation/if-ext:encaps-type/if-vlan:dot1q-vlan/if-vlan:dot1q-vlan/if-vlan:outer-tag/if-vlan:tag-type" {
+    deviate not-supported;
+  }
+
+  deviation "/if:interfaces/if:interface/if-ext:encapsulation/if-ext:encaps-type/if-vlan:dot1q-vlan/if-vlan:dot1q-vlan/if-vlan:second-tag" {
+    deviate not-supported;
+  }
+
+  /*
+  deviation "/if:interfaces/if:interface/if-ext:encapsulation/if-ext:encaps-type/if-vlan:dot1q-vlan/if-vlan:dot1q-vlan/if-vlan:second-tag/if-vlan:tag-type" {
+    deviate not-supported;
+  }
+  */
+
+  /*
+  deviation "/if:interfaces/if:interface/if-ext:encapsulation/if-ext:encaps-type/if-vlan:dot1q-vlan/if-vlan:dot1q-vlan/if-vlan:second-tag/if-vlan:vlan-id" {
+    deviate not-supported;
+  }
+  */
+}