NLnetLabs
diff --git a/‎Cargo.toml
+1-1 b/‎Cargo.toml
+1-1
diff --git a/‎Changelog.md
+91-4 b/‎Changelog.md
+91-4
diff --git a/‎fuzz/Cargo.lock
+1-1 b/‎fuzz/Cargo.lock
+1-1
diff --git a/‎fuzz/fuzz_targets/path_selection.rs
+74-2 b/‎fuzz/fuzz_targets/path_selection.rs
+74-2
@@ -1,6 +1,6 @@
 [package]
 name = "routecore"
-version = "0.5.0-rc1-dev"
+version = "0.5.0-rc1"
 authors = ["NLnet Labs <[email protected]>"]
 categories = ["network-programming"]
 description = "A Library with Building Blocks for BGP Routing"
 
@@ -1,17 +1,104 @@
-## 0.5.0-rc0
+## 0.5.0-rc1
 
-Released 2024-05-29.
+Released 2024-06-10.
+
+This release features a lot of changes, big and small. The list below is not
+exhaustive but tries to highlight and describe the bigger (and perhaps, more
+important) ones.
 
-TODO
 
 Breaking changes
 
+* Several common basic types (e.g. `Asn` and `Prefix`) are moved out of
+  _routecore_ to the new _inetnum_ crate.
+ 
+* Refactor of PathAttributes 
+
+  The introduction of `PaMap` and `RouteWorkshop` (see below) required refactoring
+  of the `PathAttributes` enum and related types. Most significantly, an entire
+  layer in the enum was removed, changing how one matches on variants.
+  Furthermore some of the types in those variants slightly changed.
+ 
+* Overhaul of address family related code
+  
+  The types describing address families, and related traits to parse and compose
+  NLRI of such families, have severely changed. This eliminates any possible
+  ambiguity regarding the address family of announcements/withdrawals in UPDATE
+  messages at compile time. 
+ 
+    * Supported address families are now explicitly and exhaustively enumerated
+      in the `AfiSafiType` enum.  As a SAFI by itself does not carry much meaning,
+      the separate `SAFI` enum is removed. Almost all of the code now works
+      based on the more descriptive `AfiSafiType`.
+    * ADD-PATH is now supported on all supported address families, i.e. the
+      `AfiSafiType` includes `~AddPath` variants for every single AFI+SAFI
+      combination. 
+    * This now allows for e.g. efficient iterators over NLRI that are generic
+      over the `AfiSafiType`.
+      But, as a possible downside, this moves the task of determining what
+      address family a set of NLRI holds to the caller in order to then use the
+      correctly typed iterator. The less efficient, 'easier to use' iterators
+      returning an enum instead of a distinct NLRI type are therefore still
+      available.
+
 New
 
-Bug fixes
+* RouteWorkshop / PaMap
+
+  This release introduces the `RouteWorkshop` to create UPDATE messages based on
+  an NLRI and a set of attributes. For creation, inspection and manipulation of
+  those attributes, the `PaMap` is introduced. These new types work in
+  conjunction with the existing `UpdateBuilder`.
+ 
+* BGP FSM (absorbed from _rotonda-fsm_)
+  
+  _routecore_ now contains the code to enable for actual BGP sessions, i.e. the
+  BGP FSM and related machinery. By pulling this in into _routecore_ allows for
+  less dependency juggling, easier development iterations and more sensible code
+  in all parts. All of this has some rough edges and is prone to changes on the
+  near future.
+
+  The _rotonda-fsm_ crate for now is left as-is.
+
+
+* Route Selection fundamentals
+
+  This release introduces a first attempt at providing handles to perform the
+  BGP Decision Process as described in RFC4271, colloquially known as 'route
+  selection' or 'best path selection'.
+  
+  Most of the heavy-lifting for this comes from implementing `Ord` on a wrapper
+  struct holding a 'route' (i.e., `PaMap`) and additional information to allow
+  tie-breaking as described in the RFC.
+  
+  As the tie-breaking in RFC4271 is actually broken and not totally ordered, we
+  aim to provide a certain degree of flexibility in the tie-breaking process by
+  means of different `OrdStrat` ordering strategies.
+
 
 Other changes
 
+* Feature flags
+
+  After splitting of parts of _routecore_ into the _inetnum_ crate, the default
+  features set resulted in an almost empty library. Therefore the `bgp` flag is
+  now on by default, and we introduced an `fsm` flag to enable the BGP FSM code
+  absorbed from _rotonda-fsm_.
+
+
+Known limitations
+
+* Constructed UPDATE messages are MultiProtocol-only
+
+  With regards to announcing and withdrawing NLRI, the `UpdateBuilder` is currently
+  limited to putting everything in the MultiProtocol path attributes
+  (MP_REACH_NLRI, MP_UNREACH_NLRI), so even for IPv4 Unicast.
+ 
+  Note that this behaviour is considered preferable as it leads to somewhat more
+  flexibility/resilience on the protocol level. But in case one of the peers
+  does not signal the capability of doing IPv4 Unicast in MultiProtocol
+  attributes, we should allow creation of PDUs in the traditional form anyway,
+  so we plan to reintroduce this functionality.
 
 
 ## 0.4.0
 
@@ -1,8 +1,14 @@
 #![no_main]
 
 use std::cmp::Ordering::*;
+use std::fmt::Debug;
 use libfuzzer_sys::fuzz_target;
-use routecore::bgp::{path_attributes::PaMap, path_selection::{OrdRoute, Rfc4271, SkipMed, TiebreakerInfo}};
+use routecore::bgp::{
+    path_attributes::PaMap,
+    path_selection::{OrdStrat, OrdRoute, Rfc4271, SkipMed, TiebreakerInfo,
+        best_backup, best_backup_generic, best
+    }
+};
 
 fn verify_ord<T>(a: &T, b: &T, c: &T)
     where T: Ord
@@ -36,6 +42,71 @@ fn verify_ord<T>(a: &T, b: &T, c: &T)
     }
 }
 
+fn verify_path_selection<'a, T, OS, I>(candidates: I)
+    where
+        I: Clone + Iterator<Item = T>,
+        T: Debug + Ord + core::borrow::Borrow<OrdRoute<'a, OS>>,
+        OS: Debug + OrdStrat,
+{
+    let best1 = best(candidates.clone()).unwrap();
+    let (best2, backup2) = best_backup(candidates.clone());
+    let best2 = best2.unwrap();
+
+    assert_eq!(best1.borrow(), best2.borrow());
+    assert_eq!(best1.borrow().pa_map(), best2.borrow().pa_map());
+    assert_eq!(best1.borrow().tiebreakers(), best2.borrow().tiebreakers());
+
+    let backup2 = match backup2 {
+        Some(route) => route,
+        None => {
+            let mut iter = candidates.clone();
+            let mut cur  = iter.next().unwrap();
+            for c in iter {
+                assert_eq!(cur.borrow().inner(), c.borrow().inner());
+                cur = c;
+            }
+            return;
+        }
+    };
+
+    assert_ne!(
+        (best2.borrow().tiebreakers(), best2.borrow().pa_map()),
+        (backup2.borrow().tiebreakers(), backup2.borrow().pa_map()),
+    );
+
+    let (best_gen, backup_gen) = verify_path_selection_generic(candidates);
+    let (best_gen, _backup_gen) = (best_gen.unwrap(), backup_gen.unwrap());
+
+    assert_eq!(best2, best_gen);
+    
+    // Because best_backup_generic can't deal with duplicates, this won't
+    // always hold:
+    //assert_eq!(backup2, backup_gen);
+
+}
+
+fn verify_path_selection_generic<I, T>(candidates: I) -> (Option<T>, Option<T>)
+where
+    I: Iterator<Item = T>,
+    T: Debug + Ord
+{
+
+    let (best, backup) = best_backup_generic(
+        // create tuples of the OrdRoute and a unique 'id'
+        candidates.enumerate().map(|(idx, c)| (c, idx))
+    );
+    // because the returned values are tuples as well, we can now compare
+    // those (instead of comparing the OrdRoute). With the unique IDs
+    // attached, we can check whether `best` and `backup` are not equal in
+    // terms of content.
+    assert!(best.is_some());
+    assert!(backup.is_some());
+    assert_ne!(best, backup);
+
+
+    (best.map(|t| t.0), backup.map(|t| t.0))
+}
+
 // XXX while doing fuzz_target!(|data: &[u8]| ... and then creating an
 // Unstructured from `data` can be useful, the Debug output becomes quite
 // useless. It'll be just a bunch of bytes without any structure.
@@ -65,8 +136,9 @@ fuzz_target!(|data: (
         Err(_) => return,
     };
 
-    //dbg!("skipmed");
     verify_ord(&a, &b, &c);
+    verify_path_selection([&a, &b, &c, &b, &c, &a].into_iter());
+    //verify_path_selection_generic([&a, &b, &c].into_iter());
 
     //dbg!("rfc4271");
     /*