From 5c1ab0f9656838dcc9e151ca33757e41a4183281 Mon Sep 17 00:00:00 2001
From: David Venhoek <david@tweedegolf.com>
Date: Fri, 13 Oct 2023 15:45:10 +0200
Subject: [PATCH] Small fixes to master only mode and the handling of announce
 messages.

---
 statime/src/bmc/bmca.rs     |  5 ++++-
 statime/src/port/mod.rs     | 34 ++++++++++++++++++++++++----------
 statime/src/ptp_instance.rs |  4 ++--
 3 files changed, 30 insertions(+), 13 deletions(-)

diff --git a/statime/src/bmc/bmca.rs b/statime/src/bmc/bmca.rs
index dcf4508db..802e36b31 100644
--- a/statime/src/bmc/bmca.rs
+++ b/statime/src/bmc/bmca.rs
@@ -193,7 +193,7 @@ impl<A: AcceptableMasterList> Bmca<A> {
         &mut self,
         header: &Header,
         announce_message: &AnnounceMessage,
-    ) {
+    ) -> bool {
         // Ignore messages comming from the same port
         if announce_message.header.source_port_identity != self.own_port_identity
             && self
@@ -205,6 +205,9 @@ impl<A: AcceptableMasterList> Bmca<A> {
                 announce_message,
                 Duration::ZERO,
             );
+            true
+        } else {
+            false
         }
     }
 
diff --git a/statime/src/port/mod.rs b/statime/src/port/mod.rs
index 4e6187dde..580e6c81e 100644
--- a/statime/src/port/mod.rs
+++ b/statime/src/port/mod.rs
@@ -309,11 +309,16 @@ impl<'a, A: AcceptableMasterList, C: Clock, F: Filter, R: Rng> Port<Running<'a>,
     fn handle_general_internal(&mut self, message: Message<'_>) -> PortActionIterator<'_> {
         match message.body {
             MessageBody::Announce(announce) => {
-                self.bmca
-                    .register_announce_message(&message.header, &announce);
-                actions![PortAction::ResetAnnounceReceiptTimer {
-                    duration: self.config.announce_duration(&mut self.rng),
-                }]
+                if self
+                    .bmca
+                    .register_announce_message(&message.header, &announce)
+                {
+                    actions![PortAction::ResetAnnounceReceiptTimer {
+                        duration: self.config.announce_duration(&mut self.rng),
+                    }]
+                } else {
+                    actions![]
+                }
             }
             _ => {
                 self.port_state
@@ -384,10 +389,11 @@ impl<'a, A, C: Clock, F: Filter, R: Rng> Port<InBmca<'a>, A, R, C, F> {
         self.bmca.step_age(step);
     }
 
-    pub(crate) fn best_local_announce_message(&self) -> Option<BestAnnounceMessage> {
+    pub(crate) fn best_local_announce_message_for_bmca(&self) -> Option<BestAnnounceMessage> {
         // Announce messages received on a masterOnly PTP Port shall not be considered
-        // in the operation of the best master clock algorithm or in the update
-        // of data sets.
+        // in the global operation of the best master clock algorithm or in the update
+        // of data sets. We still need them during the calculation of the recommended
+        // port state though to avoid getting multiple masters in the segment.
         if self.config.master_only {
             None
         } else {
@@ -395,6 +401,14 @@ impl<'a, A, C: Clock, F: Filter, R: Rng> Port<InBmca<'a>, A, R, C, F> {
         }
     }
 
+    pub(crate) fn best_local_announce_message_for_state(&self) -> Option<BestAnnounceMessage> {
+        // Announce messages received on a masterOnly PTP Port shall not be considered
+        // in the global operation of the best master clock algorithm or in the update
+        // of data sets. We still need them during the calculation of the recommended
+        // port state though to avoid getting multiple masters in the segment.
+        self.lifecycle.local_best
+    }
+
     pub(crate) fn set_recommended_state(
         &mut self,
         recommended_state: RecommendedState,
@@ -724,7 +738,7 @@ mod tests {
 
         let mut port = port.start_bmca();
         port.calculate_best_local_announce_message();
-        assert!(port.best_local_announce_message().is_some());
+        assert!(port.best_local_announce_message_for_bmca().is_some());
     }
 
     #[test]
@@ -802,6 +816,6 @@ mod tests {
 
         let mut port = port.start_bmca();
         port.calculate_best_local_announce_message();
-        assert!(port.best_local_announce_message().is_some());
+        assert!(port.best_local_announce_message_for_bmca().is_some());
     }
 }
diff --git a/statime/src/ptp_instance.rs b/statime/src/ptp_instance.rs
index de560d457..15200131a 100644
--- a/statime/src/ptp_instance.rs
+++ b/statime/src/ptp_instance.rs
@@ -91,14 +91,14 @@ impl PtpInstanceState {
         let ebest = Bmca::<()>::find_best_announce_message(
             ports
                 .iter()
-                .filter_map(|port| port.best_local_announce_message()),
+                .filter_map(|port| port.best_local_announce_message_for_bmca()),
         );
 
         for port in ports.iter_mut() {
             let recommended_state = Bmca::<()>::calculate_recommended_state(
                 &self.default_ds,
                 ebest,
-                port.best_local_announce_message(), // erbest
+                port.best_local_announce_message_for_state(), // erbest
                 port.state(),
             );