Kernel <-> KernelAdapter

src/bgp/mod.rs

@@ -4,7 +4,7 @@ pub mod nlri;
 pub mod route;
 
 use crate::args::RunArgs;
-use crate::kernel::{self, Kernel};
+use crate::kernel::{self, KernelAdapter};
 use crate::net::{Afi, IpPrefixError, IpPrefixErrorKind};
 use either::Either;
 use flow::FlowError;
@@ -62,9 +62,9 @@ pub struct Session<S: AsyncRead + AsyncWrite + Unpin> {
 impl<S: AsyncRead + AsyncWrite + Unpin> Session<S> {
   pub async fn new(c: RunArgs) -> Result<Self> {
     let kernel = if c.dry_run {
-      Kernel::Noop
+      KernelAdapter::Noop
     } else {
-      Kernel::linux(c.kernel.clone()).await?
+      KernelAdapter::linux(c.kernel.clone()).await?
     };
     Ok(Self { config: c, state: Active, routes: Routes::new(kernel) })
   }

src/bgp/route.rs

@@ -22,11 +22,11 @@ use strum::{EnumDiscriminants, FromRepr};
 pub struct Routes {
   unicast: BTreeMap<IpPrefix, (NextHop, MaybeRc<RouteInfo<'static>>)>,
   flow: BTreeMap<Flowspec, (KernelHandle, MaybeRc<RouteInfo<'static>>)>,
-  kernel: Kernel,
+  kernel: KernelAdapter,
 }
 
 impl Routes {
-  pub fn new(kernel: Kernel) -> Self {
+  pub fn new(kernel: KernelAdapter) -> Self {
     Self { unicast: BTreeMap::new(), flow: BTreeMap::new(), kernel }
   }
 

src/kernel/linux/mod.rs

@@ -1,7 +1,7 @@
 mod nft;
 
 use super::rtnl::{RtNetlink, RtNetlinkArgs};
-use super::{KernelAdapter, Result};
+use super::{Kernel, Result};
 use crate::bgp::flow::Flowspec;
 use crate::bgp::route::RouteInfo;
 use clap::Args;
@@ -35,7 +35,7 @@ impl Linux {
   }
 }
 
-impl KernelAdapter for Linux {
+impl Kernel for Linux {
   type Handle = u64;
 
   async fn apply(&mut self, spec: &Flowspec, info: &RouteInfo<'_>) -> Result<Self::Handle> {

src/kernel/mod.rs

@@ -1,7 +1,7 @@
 //! Bridges flowspecs to OS kernel.
 //!
-//! Currently only Linux is supported, which uses nftables. Future support may
-//! include *BSD using `pf` as backend.
+//! Currently only Linux is supported. Future support may include *BSD using
+//! `pf` as backend.
 
 #[cfg(target_os = "linux")]
 mod linux;
@@ -19,30 +19,42 @@ use std::future::Future;
 use strum::Display;
 use thiserror::Error;
 
-pub trait KernelAdapter {
+/// Interface between BGP flowspec and the OS.
+pub trait Kernel {
+  /// Type representing a flowspec's counterpart in kernel.
   type Handle;
+
+  /// Apply a flowspec to kernel.
   fn apply(&mut self, spec: &Flowspec, info: &RouteInfo<'_>) -> impl Future<Output = Result<Self::Handle>>;
+
+  /// Remove a flowspec from kernel using previously returned handle.
   fn remove(&mut self, handle: Self::Handle) -> impl Future<Output = Result<()>>;
+
+  /// Process notifications from kernel, timers, etc.
   fn process(&mut self) -> impl Future<Output = Result<()>> {
     pending()
   }
 }
 
+/// Adapter of different `Kernel` implementations.
 #[derive(Debug, Serialize, Deserialize)]
-pub enum Kernel {
+pub enum KernelAdapter {
+  /// Do nothing.
   Noop,
+
+  /// Linux implementation, using nftables and rtnetlink.
   #[cfg(target_os = "linux")]
   Linux(Linux),
 }
 
-impl Kernel {
+impl KernelAdapter {
   #[cfg(target_os = "linux")]
   pub async fn linux(args: KernelArgs) -> Result<Self> {
     Ok(Self::Linux(Linux::new(args).await?))
   }
 }
 
-impl KernelAdapter for Kernel {
+impl Kernel for KernelAdapter {
   type Handle = KernelHandle;
 
   async fn apply(&mut self, spec: &Flowspec, info: &RouteInfo<'_>) -> Result<Self::Handle> {
@@ -75,7 +87,7 @@ pub enum KernelHandle {
 
   #[cfg(target_os = "linux")]
   #[strum(to_string = "{0}")]
-  Linux(<Linux as KernelAdapter>::Handle),
+  Linux(<Linux as Kernel>::Handle),
 }
 
 #[derive(Debug, Error)]

src/kernel/rtnl.rs

@@ -65,6 +65,7 @@ impl RtNetlink {
       .filter(|(_, v)| v.iter().all(|p| !p.overlaps(prefix)))
       .next()
     {
+      // there's a table whose content doesn't overlap with our prefix, we reuse it
       prefixes.insert(prefix);
       *table_id
     } else {
@@ -84,7 +85,6 @@ impl RtNetlink {
         .priority(self.args.rt_rule_priority)
         .execute()
         .await?;
-      self.handle.rule().get(rtnetlink::IpVersion::V4);
       table_id
     };