ospf: Add RFC 9339 support

holo-ospf/src/events.rs

@@ -5,7 +5,7 @@
 //
 
 use std::cmp::Ordering;
-use std::collections::btree_map;
+use std::collections::btree_map::{self, Entry};
 use std::net::Ipv4Addr;
 use std::sync::Arc;
 
@@ -29,6 +29,7 @@ use crate::lsdb::{
 use crate::neighbor::{LastDbDesc, Neighbor, RxmtPacketType, nsm};
 use crate::northbound::notification;
 use crate::packet::error::DecodeResult;
+use crate::packet::lls::ReverseMetricFlags;
 use crate::packet::lsa::{
     Lsa, LsaBodyVersion, LsaHdrVersion, LsaKey, LsaScope, LsaTypeVersion,
 };
@@ -431,9 +432,55 @@ where
     // Examine LLS data block if enabled and present in the packet.
     if iface.config.lls_enabled
         && hello.options().l_bit()
-        && let Some(_lls) = hello.lls()
+        && let Some(lls) = hello.lls()
     {
-        // TODO: Handle LLS data
+        // Handle Reverse Metric (RFC 9339).
+        if iface.config.reverse_metric.receive {
+            // We have to recall the latest configuration we have received.
+            // If it has not changed, we do not update the metric nor we
+            // originate a new Router LSA.
+            // If the Reverse Metric from the neighbor has been updated since
+            // the last one we received, then we propagate the information.
+            for (mtid, (flags, metric)) in lls.reverse_metric.iter() {
+                let entry = iface.state.rms.entry(*mtid);
+                if let Some((flags, metric)) = match entry {
+                    Entry::Occupied(entry) => {
+                        // Has the RM changed?
+                        let (old_flags, old_metric) = entry.into_mut();
+                        (old_metric != metric || old_flags != flags).then(
+                            || {
+                                *old_metric = *metric;
+                                *old_flags = *flags;
+                                (*old_flags, *old_metric)
+                            },
+                        )
+                    }
+                    Entry::Vacant(entry) => {
+                        // This is the first time we see the RM.
+                        Some(*entry.insert((*flags, *metric)))
+                    }
+                } {
+                    // Update metric.
+                    // RFC 9339 Section 6 : "The H and O flags are mutually
+                    // exclusive; the H flag is ignored when the O flag is set."
+                    let higher = flags.contains(ReverseMetricFlags::H);
+                    let offset = flags.contains(ReverseMetricFlags::O);
+                    if offset {
+                        iface.state.cost =
+                            iface.state.cost.saturating_add(metric);
+                    } else if !higher || iface.state.cost < metric {
+                        iface.state.cost = metric;
+                    }
+
+                    // Trigger Router LSA origination.
+                    instance.tx.protocol_input.lsa_orig_event(
+                        LsaOriginateEvent::InterfaceCostChange {
+                            area_id: area.id,
+                        },
+                    );
+                }
+            }
+        }
     }
 
     Ok(())

holo-ospf/src/interface.rs

@@ -34,6 +34,7 @@ use crate::northbound::configuration::InterfaceCfg;
 use crate::northbound::notification;
 use crate::packet::Packet;
 use crate::packet::auth::AuthMethod;
+use crate::packet::lls::ReverseMetricFlags;
 use crate::packet::lsa::{Lsa, LsaHdrVersion, LsaKey};
 use crate::tasks;
 use crate::tasks::messages::output::NetTxPacketMsg;
@@ -97,6 +98,10 @@ pub struct InterfaceState<V: Version> {
     pub auth: Option<AuthMethod>,
     // Tasks.
     pub tasks: InterfaceTasks<V>,
+    // Dynamic value of the interface cost.
+    pub cost: u16,
+    // History of known Reverse Metric received on this interface.
+    pub rms: BTreeMap<u8, (ReverseMetricFlags, u16)>,
 }
 
 #[derive(Debug)]
@@ -255,12 +260,16 @@ where
     ) -> Interface<V> {
         Debug::<V>::InterfaceCreate(&name).log();
 
+        let config = InterfaceCfg::default();
+        let mut state = InterfaceState::default();
+        state.cost = config.cost;
+
         Interface {
             id,
             name,
             system: InterfaceSys::default(),
-            config: InterfaceCfg::default(),
-            state: InterfaceState::default(),
+            config,
+            state,
             vlink_key,
         }
     }
@@ -1016,6 +1025,8 @@ where
             network_lsa_self: None,
             auth: None,
             tasks: Default::default(),
+            cost: 0,
+            rms: Default::default(),
         }
     }
 }

holo-ospf/src/northbound/configuration.rs

@@ -177,6 +177,15 @@ pub struct RangeCfg {
     pub cost: Option<u32>,
 }
 
+#[derive(Debug)]
+pub struct ReverseMetricCfg {
+    pub receive: bool,
+    pub mtid: u8,
+    pub metric: Option<u16>,
+    pub higher: bool,
+    pub offset: bool,
+}
+
 #[derive(Debug)]
 pub struct InterfaceCfg<V: Version> {
     pub instance_id: InheritableConfig<u8>,
@@ -199,6 +208,7 @@ pub struct InterfaceCfg<V: Version> {
     pub bfd_params: bfd::ClientCfg,
     pub trace_opts: InterfaceTraceOptions,
     pub lls_enabled: bool,
+    pub reverse_metric: ReverseMetricCfg,
 }
 
 #[derive(Debug)]
@@ -989,6 +999,7 @@ where
 
             let cost = args.dnode.get_u16();
             iface.config.cost = cost;
+            iface.state.cost = cost;
 
             let event_queue = args.event_queue;
             event_queue.insert(Event::InterfaceCostChange(area_idx));
@@ -1232,7 +1243,88 @@ where
             let event_queue = args.event_queue;
             event_queue.insert(Event::UpdateTraceOptions);
         })
+        .path(ospf::areas::area::interfaces::interface::reverse_metric::enable_receive::PATH)
+        .modify_apply(|instance, args| {
+            let (_, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
+
+            let receive = args.dnode.get_bool();
+            iface.config.reverse_metric.receive = receive;
+        })
+        .path(ospf::areas::area::interfaces::interface::reverse_metric::metric::PATH)
+        .modify_apply(|instance, args| {
+            let (area_idx, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
+
+            let metric = args.dnode.get_u16();
+            iface.config.reverse_metric.metric = Some(metric);
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::InterfaceSyncHelloTx(area_idx, iface_idx));
+        })
+        .delete_apply(|instance, args| {
+            let (area_idx, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
+
+            iface.config.reverse_metric.metric = None;
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::InterfaceSyncHelloTx(area_idx, iface_idx));
+        })
+        .path(ospf::areas::area::interfaces::interface::reverse_metric::flags::higher::PATH)
+        .modify_apply(|instance, args| {
+            let (area_idx, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
 
+            let higher = args.dnode.get_bool();
+            iface.config.reverse_metric.higher = higher;
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::InterfaceSyncHelloTx(area_idx, iface_idx));
+        })
+        .path(ospf::areas::area::interfaces::interface::reverse_metric::flags::offset::PATH)
+        .modify_apply(|instance, args| {
+            let (area_idx, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
+
+            let offset = args.dnode.get_bool();
+            iface.config.reverse_metric.offset = offset;
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::InterfaceSyncHelloTx(area_idx, iface_idx));
+        })
+        .path(ospf::areas::area::interfaces::interface::reverse_metric::mtid::PATH)
+        .modify_apply(|instance, args| {
+            let (area_idx, iface_idx) =
+                args.list_entry.into_interface().unwrap();
+            let iface = &mut instance.arenas.interfaces[iface_idx];
+
+            let mtid = args.dnode.get_u8();
+            iface.config.reverse_metric.mtid = mtid;
+
+            let event_queue = args.event_queue;
+            event_queue.insert(Event::InterfaceSyncHelloTx(area_idx, iface_idx));
+        })
+        .path(ospf::areas::area::reverse_metric::enable_receive::PATH)
+        .modify_apply(|instance, args| {
+            let area_idx = args.list_entry.into_area().unwrap();
+            let receive = args.dnode.get_bool();
+            instance.arenas.interfaces.iter_mut().filter(|(area, _)| area == &area_idx).for_each(|(_, iface)| {
+                iface.config.reverse_metric.receive = receive;
+            });
+        })
+        .path(ospf::reverse_metric::enable_receive::PATH)
+        .modify_apply(|instance, args| {
+            let receive = args.dnode.get_bool();
+            instance.arenas.interfaces.iter_mut().for_each(|(_, iface)| {
+                iface.config.reverse_metric.receive = receive;
+            });
+        })
         .build()
 }
 
@@ -2407,6 +2499,23 @@ impl Default for RangeCfg {
     }
 }
 
+impl Default for ReverseMetricCfg {
+    fn default() -> Self {
+        let receive = ospf::areas::area::interfaces::interface::reverse_metric::enable_receive::DFLT;
+        let metric = None;
+        let higher = ospf::areas::area::interfaces::interface::reverse_metric::flags::higher::DFLT;
+        let offset = ospf::areas::area::interfaces::interface::reverse_metric::flags::offset::DFLT;
+        let mtid = ospf::areas::area::interfaces::interface::reverse_metric::mtid::DFLT;
+        Self {
+            receive,
+            metric,
+            higher,
+            offset,
+            mtid,
+        }
+    }
+}
+
 impl<V> Default for InterfaceCfg<V>
 where
     V: Version,
@@ -2455,6 +2564,7 @@ where
             bfd_params: Default::default(),
             trace_opts: Default::default(),
             lls_enabled,
+            reverse_metric: Default::default(),
         }
     }
 }

holo-ospf/src/northbound/mod.rs

@@ -41,6 +41,7 @@ where
             "ietf-ospfv3-extended-lsa",
             "holo-ospf",
             "holo-ospf-dev",
+            "holo-ospf-reverse-metric",
         ]
     }
 

holo-ospf/src/ospfv2/interface.rs

@@ -21,6 +21,7 @@ use crate::network::{MulticastAddr, NetworkVersion};
 use crate::ospfv2;
 use crate::ospfv2::packet::{Hello, PacketHdr};
 use crate::packet::auth::AuthMethod;
+use crate::packet::lls::{LlsHelloData, ReverseMetricFlags};
 use crate::packet::{Packet, PacketType};
 use crate::version::Ospfv2;
 
@@ -62,12 +63,25 @@ impl InterfaceVersion<Self> for Ospfv2 {
             iface.system.primary_addr.unwrap().mask()
         };
 
-        let lls = if iface.config.lls_enabled {
-            // TODO: Get LLS configuration
-            None
-        } else {
-            None
-        };
+        let advertise_rm = iface.config.reverse_metric.metric.is_some();
+        let lls = (iface.config.lls_enabled & advertise_rm).then(|| {
+            let mut lls_data: LlsHelloData = Default::default();
+
+            // Handle Reverse Metric (RFC 9339).
+            if let Some(metric) = iface.config.reverse_metric.metric {
+                let cfg = &iface.config.reverse_metric;
+                let mut flags = ReverseMetricFlags::empty();
+                if cfg.higher {
+                    flags |= ReverseMetricFlags::H;
+                }
+                if cfg.offset {
+                    flags |= ReverseMetricFlags::O;
+                }
+                lls_data.reverse_metric.insert(cfg.mtid, (flags, metric));
+            }
+
+            lls_data
+        });
 
         Packet::Hello(Hello {
             hdr,

holo-ospf/src/ospfv2/lsdb.rs

@@ -451,7 +451,7 @@ fn lsa_orig_router(
         let non_stub_cost = if instance.config.stub_router {
             MAX_LINK_METRIC
         } else {
-            iface.config.cost
+            iface.state.cost
         };
 
         let mut add_stub_links = false;
@@ -551,7 +551,7 @@ fn lsa_orig_router(
                             LsaRouterLinkType::StubNetwork,
                             addr.ip(),
                             addr.mask(),
-                            iface.config.cost,
+                            iface.state.cost,
                         )
                     }),
             );