bgp, routing: convert RIB to use prefix-trie

For storing routing tables, we need a data structure where we can do longest-prefix matches, a requirement for things like BGP nexthop resolution, policy application, among others. For that, we'll be using the prefix-trie crate, which has excellent performance numbers, an ergonomic API similar to std::collections, and no additional dependencies. The transition to prefix-trie is straightforward due to its API's similarity to BTreeMap. Signed-off-by: Renato Westphal <[email protected]>
holo-routing · Mar 11, 2024 · e9413e5 · e9413e5
1 parent dfb0aae
commit e9413e5
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Showing 8 changed files with 14 additions and 9 deletions.
diff --git a/Cargo.toml b/Cargo.toml
@@ -54,6 +54,7 @@ netlink-sys = "0.8"
 num-derive = "0.3"
 num-traits = "0.2"
 pickledb = "0.5"
+prefix-trie = { version = "0.3", features = ["ipnetwork"]  }
 prost = "0.12"
 rand = "0.8.5"
 rtnetlink = "0.13"

diff --git a/holo-bgp/Cargo.toml b/holo-bgp/Cargo.toml
@@ -19,6 +19,7 @@ itertools.workspace = true
 libc.workspace = true
 num-derive.workspace = true
 num-traits.workspace = true
+prefix-trie.workspace = true
 rand.workspace = true
 serde.workspace = true
 serde_json.workspace = true

diff --git a/holo-bgp/src/af.rs b/holo-bgp/src/af.rs
@@ -33,7 +33,7 @@ pub trait AddressFamily: Sized {
     // The type of IP address used by this address family.
     type IpAddr: IpAddrKind;
     // The type of IP network used by this address family.
-    type IpNetwork: IpNetworkKind<Self::IpAddr>;
+    type IpNetwork: IpNetworkKind<Self::IpAddr> + prefix_trie::Prefix;
 
     // Get the routing table for this address family from the provided
     // `RoutingTables`.

diff --git a/holo-bgp/src/neighbor.rs b/holo-bgp/src/neighbor.rs
@@ -913,7 +913,7 @@ impl Neighbor {
         A: AddressFamily,
     {
         let table = A::table(&mut rib.tables);
-        for (prefix, dest) in &mut table.prefixes {
+        for (prefix, dest) in table.prefixes.iter_mut() {
             dest.adj_rib.remove(&self.remote_addr);
             table.queued_prefixes.insert(*prefix);
         }

diff --git a/holo-bgp/src/northbound/state.rs b/holo-bgp/src/northbound/state.rs
@@ -91,8 +91,8 @@ fn load_callbacks() -> Callbacks<Instance> {
             let afi_safi = args.list_entry.as_global_afi_safi().unwrap();
             let state = instance.state.as_ref().unwrap();
             let total = match afi_safi {
-                AfiSafi::Ipv4Unicast => state.rib.tables.ipv4_unicast.prefixes.len(),
-                AfiSafi::Ipv6Unicast => state.rib.tables.ipv6_unicast.prefixes.len(),
+                AfiSafi::Ipv4Unicast => state.rib.tables.ipv4_unicast.prefixes.iter().count(),
+                AfiSafi::Ipv6Unicast => state.rib.tables.ipv6_unicast.prefixes.iter().count(),
             };
             Some(total as u32)
         })
@@ -134,8 +134,8 @@ fn load_callbacks() -> Callbacks<Instance> {
         .path(bgp::global::statistics::total_prefixes::PATH)
         .get_element_u32(|instance, _args| {
             if let Some(state) = &instance.state {
-                let total = state.rib.tables.ipv4_unicast.prefixes.len()
-                    + state.rib.tables.ipv6_unicast.prefixes.len();
+                let total = state.rib.tables.ipv4_unicast.prefixes.iter().count()
+                    + state.rib.tables.ipv6_unicast.prefixes.iter().count();
                 Some(total as u32)
             } else {
                 None

diff --git a/holo-bgp/src/rib.rs b/holo-bgp/src/rib.rs
@@ -13,6 +13,7 @@ use std::time::Instant;
 use holo_utils::bgp::RouteType;
 use holo_utils::ibus::IbusSender;
 use holo_utils::protocol::Protocol;
+use prefix_trie::map::PrefixMap;
 use serde::{Deserialize, Serialize};
 
 use crate::af::{AddressFamily, Ipv4Unicast, Ipv6Unicast};
@@ -46,7 +47,7 @@ pub struct RoutingTables {
 
 #[derive(Debug)]
 pub struct RoutingTable<A: AddressFamily> {
-    pub prefixes: BTreeMap<A::IpNetwork, Destination>,
+    pub prefixes: PrefixMap<A::IpNetwork, Destination>,
     pub queued_prefixes: BTreeSet<A::IpNetwork>,
 }
 

diff --git a/holo-routing/Cargo.toml b/holo-routing/Cargo.toml
@@ -16,6 +16,7 @@ derive-new.workspace = true
 enum-as-inner.workspace = true
 futures.workspace = true
 ipnetwork.workspace = true
+prefix-trie.workspace = true
 rtnetlink.workspace = true
 tokio.workspace = true
 tracing.workspace = true

diff --git a/holo-routing/src/rib.rs b/holo-routing/src/rib.rs
@@ -20,14 +20,15 @@ use holo_utils::southbound::{
 };
 use holo_utils::{UnboundedReceiver, UnboundedSender};
 use ipnetwork::{IpNetwork, Ipv4Network, Ipv6Network};
+use prefix_trie::map::PrefixMap;
 use tokio::sync::mpsc;
 
 use crate::{ibus, netlink};
 
 #[derive(Debug)]
 pub struct Rib {
-    pub ipv4: BTreeMap<Ipv4Network, BTreeMap<u32, Route>>,
-    pub ipv6: BTreeMap<Ipv6Network, BTreeMap<u32, Route>>,
+    pub ipv4: PrefixMap<Ipv4Network, BTreeMap<u32, Route>>,
+    pub ipv6: PrefixMap<Ipv6Network, BTreeMap<u32, Route>>,
     pub mpls: BTreeMap<Label, Route>,
     pub ip_update_queue: BTreeSet<IpNetwork>,
     pub mpls_update_queue: BTreeSet<Label>,