system: introduce the holo-system component

Introduce `holo-system`, implementing the following subset of the
ietf-system YANG module:

module: ietf-system
  +--rw system
  |  +--rw contact?    string
  |  +--rw hostname?   inet:domain-name
  |  +--rw location?   string
  +--ro system-state
     +--ro platform
     |  +--ro os-name?      string
     |  +--ro os-release?   string
     |  +--ro os-version?   string
     |  +--ro machine?      string
     +--ro clock
        +--ro current-datetime?   yang:date-and-time
        +--ro boot-datetime?      yang:date-and-time

The main motivation for this component is to provide a centralized
place for storing hostname information and sharing it with protocol
instances (both IS-IS and OSPF have TLVs for flooding hostname
information). Additionally, including the hostname in the configuration
is necessary for implementing a persistent hostname in holo-cli.

Closes #20

Signed-off-by: Renato Westphal <[email protected]>

Cargo.toml

@@ -12,6 +12,7 @@ members = [
   "holo-protocol",
   "holo-rip",
   "holo-routing",
+  "holo-system",
   "holo-tools",
   "holo-utils",
   "holo-yang",

README.md

@@ -234,6 +234,7 @@ Holo supports the following IETF RFCs and Internet drafts:
 | ietf-routing@2018-03-13 | 100.00% | 85.71% | - | - | [92.31%](http://westphal.com.br/holo/ietf-routing.html) |
 | ietf-segment-routing-mpls@2021-05-26 | 62.50% | 0.00% | - | 23.53% | [32.76%](http://westphal.com.br/holo/ietf-segment-routing-mpls.html) |
 | ietf-segment-routing@2021-05-26 | 100.00% | - | - | - | [100.00%](http://westphal.com.br/holo/ietf-segment-routing.html) |
+| ietf-system@2014-08-06 | 26.67% | 60.00% | 0.00% | - | [38.24%](http://westphal.com.br/holo/[email protected]) |
 
 ## Funding
 

holo-daemon/Cargo.toml

@@ -41,6 +41,7 @@ holo-policy = { path = "../holo-policy", optional = true }
 holo-protocol = { path = "../holo-protocol" }
 holo-rip = { path = "../holo-rip", optional = true }
 holo-routing = { path = "../holo-routing", optional = true  }
+holo-system = { path = "../holo-system", optional = true }
 holo-utils = { path = "../holo-utils" }
 holo-yang = { path = "../holo-yang" }
 
@@ -61,6 +62,7 @@ default = [
   "keychain",
   "policy",
   "routing",
+  "system",
   # Protocols
   "bfd",
   "bgp",
@@ -74,6 +76,7 @@ interface = ["dep:holo-interface"]
 keychain = ["dep:holo-keychain"]
 policy = ["dep:holo-policy", "dep:holo-routing"]
 routing = ["dep:holo-routing", "dep:holo-interface"]
+system = ["dep:holo-system"]
 
 # Protocols
 bfd = ["dep:holo-bfd", "holo-routing/bfd"]

holo-daemon/src/northbound/core.rs

@@ -638,7 +638,8 @@ fn start_providers(
     let ibus_rx_routing = ibus_tx.subscribe();
     let ibus_rx_interface = ibus_tx.subscribe();
     let ibus_rx_keychain = ibus_tx.subscribe();
-    let ibus_rx_policy = ibus_rx;
+    let ibus_rx_policy = ibus_tx.subscribe();
+    let ibus_rx_system = ibus_rx;
 
     // Start holo-interface.
     #[cfg(feature = "interface")]
@@ -673,6 +674,17 @@ fn start_providers(
         providers.push(daemon_tx);
     }
 
+    // Start holo-system.
+    #[cfg(feature = "system")]
+    {
+        let daemon_tx = holo_system::start(
+            provider_tx.clone(),
+            ibus_tx.clone(),
+            ibus_rx_system,
+        );
+        providers.push(daemon_tx);
+    }
+
     // Start holo-routing.
     #[cfg(feature = "routing")]
     {

holo-daemon/src/northbound/yang.rs

@@ -38,6 +38,9 @@ pub(crate) fn create_context() {
     #[cfg(feature = "policy")]
     modules_add::<holo_policy::Master>(&mut modules);
 
+    #[cfg(feature = "system")]
+    modules_add::<holo_system::Master>(&mut modules);
+
     // Add protocol modules based on enabled features.
     #[cfg(feature = "bfd")]
     {

holo-system/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "holo-system"
+version.workspace = true
+authors.workspace = true
+license.workspace = true
+edition.workspace = true
+
+[dependencies]
+sysinfo = "0.30"
+
+async-trait.workspace = true
+capctl.workspace = true
+chrono.workspace = true
+derive-new.workspace = true
+tokio.workspace = true
+tracing.workspace = true
+yang3.workspace = true
+
+holo-northbound = { path = "../holo-northbound" }
+holo-utils = { path = "../holo-utils" }
+holo-yang = { path = "../holo-yang" }
+
+[lints]
+workspace = true

holo-system/LICENSE

@@ -0,0 +1,19 @@
+Copyright (c) 2023 The Holo Core Contributors
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

holo-system/src/ibus.rs

@@ -0,0 +1,38 @@
+//
+// Copyright (c) The Holo Core Contributors
+//
+// SPDX-License-Identifier: MIT
+//
+
+use holo_utils::ibus::{IbusMsg, IbusSender};
+
+use crate::Master;
+
+// ===== global functions =====
+
+pub(crate) fn process_msg(master: &mut Master, msg: IbusMsg) {
+    match msg {
+        IbusMsg::HostnameQuery => {
+            notify_hostname_update(
+                &master.ibus_tx,
+                master.config.hostname.clone(),
+            );
+        }
+        // Ignore other events.
+        _ => {}
+    }
+}
+
+pub(crate) fn notify_hostname_update(
+    ibus_tx: &IbusSender,
+    hostname: Option<String>,
+) {
+    let msg = IbusMsg::HostnameUpdate(hostname);
+    notify(ibus_tx, msg);
+}
+
+// ===== helper functions =====
+
+fn notify(ibus_tx: &IbusSender, msg: IbusMsg) {
+    let _ = ibus_tx.send(msg);
+}

holo-system/src/lib.rs

@@ -0,0 +1,81 @@
+//
+// Copyright (c) The Holo Core Contributors
+//
+// SPDX-License-Identifier: MIT
+//
+
+#![feature(let_chains)]
+
+mod ibus;
+pub mod northbound;
+
+use holo_northbound::{
+    process_northbound_msg, NbDaemonReceiver, NbDaemonSender, NbProviderSender,
+    ProviderBase,
+};
+use holo_utils::ibus::{IbusReceiver, IbusSender};
+use northbound::configuration::SystemCfg;
+use tokio::sync::mpsc;
+use tracing::Instrument;
+
+#[derive(Debug)]
+pub struct Master {
+    // Northbound Tx channel.
+    pub nb_tx: NbProviderSender,
+    // Internal bus Tx channel.
+    pub ibus_tx: IbusSender,
+    // System configuration.
+    pub config: SystemCfg,
+}
+
+// ===== impl Master =====
+
+impl Master {
+    async fn run(
+        &mut self,
+        mut nb_rx: NbDaemonReceiver,
+        mut ibus_rx: IbusReceiver,
+    ) {
+        let mut resources = vec![];
+
+        loop {
+            tokio::select! {
+                Some(request) = nb_rx.recv() => {
+                    process_northbound_msg(
+                        self,
+                        &mut resources,
+                        request,
+                    )
+                    .await;
+                }
+                Ok(msg) = ibus_rx.recv() => {
+                    ibus::process_msg(self, msg);
+                }
+            }
+        }
+    }
+}
+
+// ===== global functions =====
+
+pub fn start(
+    nb_tx: NbProviderSender,
+    ibus_tx: IbusSender,
+    ibus_rx: IbusReceiver,
+) -> NbDaemonSender {
+    let (nb_daemon_tx, nb_daemon_rx) = mpsc::channel(4);
+
+    tokio::spawn(async move {
+        let mut master = Master {
+            nb_tx,
+            ibus_tx,
+            config: Default::default(),
+        };
+
+        // Run task main loop.
+        let span = Master::debug_span("");
+        master.run(nb_daemon_rx, ibus_rx).instrument(span).await;
+    });
+
+    nb_daemon_tx
+}

holo-system/src/northbound/configuration.rs

@@ -0,0 +1,103 @@
+//
+// Copyright (c) The Holo Core Contributors
+//
+// SPDX-License-Identifier: MIT
+//
+
+use std::sync::LazyLock as Lazy;
+
+use async_trait::async_trait;
+use holo_northbound::configuration::{
+    self, Callbacks, CallbacksBuilder, Provider,
+};
+use holo_northbound::yang::system;
+use holo_utils::yang::DataNodeRefExt;
+
+use crate::{ibus, Master};
+
+static CALLBACKS: Lazy<configuration::Callbacks<Master>> =
+    Lazy::new(load_callbacks);
+
+#[derive(Debug, Default)]
+pub enum ListEntry {
+    #[default]
+    None,
+}
+
+#[derive(Debug)]
+pub enum Resource {}
+
+#[derive(Debug, Eq, Ord, PartialEq, PartialOrd)]
+pub enum Event {
+    HostnameChange,
+}
+
+// ===== configuration structs =====
+
+#[derive(Debug, Default)]
+pub struct SystemCfg {
+    pub contact: Option<String>,
+    pub hostname: Option<String>,
+    pub location: Option<String>,
+}
+
+// ===== callbacks =====
+
+fn load_callbacks() -> Callbacks<Master> {
+    CallbacksBuilder::<Master>::default()
+        .path(system::contact::PATH)
+        .modify_apply(|master, args| {
+            let contact = args.dnode.get_string();
+            master.config.contact = Some(contact);
+        })
+        .delete_apply(|master, _args| {
+            master.config.contact = None;
+        })
+        .path(system::hostname::PATH)
+        .modify_apply(|master, args| {
+            let hostname = args.dnode.get_string();
+            master.config.hostname = Some(hostname);
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::HostnameChange);
+        })
+        .delete_apply(|master, args| {
+            master.config.hostname = None;
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::HostnameChange);
+        })
+        .path(system::location::PATH)
+        .modify_apply(|master, args| {
+            let location = args.dnode.get_string();
+            master.config.location = Some(location);
+        })
+        .delete_apply(|master, _args| {
+            master.config.location = None;
+        })
+        .build()
+}
+
+// ===== impl Master =====
+
+#[async_trait]
+impl Provider for Master {
+    type ListEntry = ListEntry;
+    type Event = Event;
+    type Resource = Resource;
+
+    fn callbacks() -> Option<&'static Callbacks<Master>> {
+        Some(&CALLBACKS)
+    }
+
+    async fn process_event(&mut self, event: Event) {
+        match event {
+            Event::HostnameChange => {
+                ibus::notify_hostname_update(
+                    &self.ibus_tx,
+                    self.config.hostname.clone(),
+                );
+            }
+        }
+    }
+}

holo-system/src/northbound/mod.rs

@@ -0,0 +1,32 @@
+//
+// Copyright (c) The Holo Core Contributors
+//
+// SPDX-License-Identifier: MIT
+//
+
+pub mod configuration;
+pub mod state;
+
+use holo_northbound::{rpc, ProviderBase};
+use tracing::{debug_span, Span};
+
+use crate::Master;
+
+// ===== impl Master =====
+
+impl ProviderBase for Master {
+    fn yang_modules() -> &'static [&'static str] {
+        &["ietf-system"]
+    }
+
+    fn top_level_node(&self) -> String {
+        "/ietf-system:system".to_owned()
+    }
+
+    fn debug_span(_name: &str) -> Span {
+        debug_span!("system")
+    }
+}
+
+// No RPC/Actions to implement.
+impl rpc::Provider for Master {}