feat: joins_allowed flag to toggle accept new node or not

src/consensus/vote.rs

@@ -58,6 +58,9 @@ pub(crate) enum Vote {
         message: Box<PlainMessage>,
         proof_chain: SectionProofChain,
     },
+
+    // Voted to concensus whether new node shall be allowed to join
+    JoinsAllowed(bool),
 }
 
 impl Vote {
@@ -95,6 +98,7 @@ impl<'a> Serialize for SignableView<'a> {
             Vote::TheirKey { prefix, key } => (prefix, key).serialize(serializer),
             Vote::TheirKnowledge { prefix, key_index } => (prefix, key_index).serialize(serializer),
             Vote::SendMessage { message, .. } => message.as_signable().serialize(serializer),
+            Vote::JoinsAllowed(joins_allowed) => joins_allowed.serialize(serializer),
         }
     }
 }

src/routing/approved.rs

@@ -55,6 +55,7 @@ pub(crate) struct Approved {
     relocate_state: Option<RelocateState>,
     msg_filter: MessageFilter,
     pub(super) event_tx: mpsc::UnboundedSender<Event>,
+    joins_allowed: bool,
 }
 
 impl Approved {
@@ -84,6 +85,7 @@ impl Approved {
             relocate_state: None,
             msg_filter: MessageFilter::new(),
             event_tx,
+            joins_allowed: true,
         }
     }
 
@@ -196,6 +198,10 @@ impl Approved {
                 proof_chain,
                 proof,
             )?]),
+            Vote::JoinsAllowed(joins_allowed) => {
+                self.joins_allowed = joins_allowed;
+                Ok(vec![])
+            }
         }
     }
 
@@ -992,6 +998,12 @@ impl Approved {
                     Some(details.pub_id),
                     Some(details.destination_key),
                 )
+            } else if !self.joins_allowed {
+                debug!(
+                    "Ignoring JoinRequest from {} - new node not acceptable.",
+                    pub_id,
+                );
+                return Ok(vec![]);
             } else {
                 (MIN_AGE, None, None)
             };
@@ -1405,6 +1417,7 @@ impl Approved {
     fn update_state(&mut self, section: Section, network: Network) -> Result<Vec<Command>> {
         let mut commands = vec![];
 
+        let old_elders_info = self.section.elders_info().clone();
         let old_is_elder = self.is_elder();
         let old_last_key_index = self.section.chain().last_key_index();
         let old_prefix = *self.section.prefix();
@@ -1476,6 +1489,9 @@ impl Approved {
 
         if !new_is_elder {
             commands.extend(self.return_relocate_promise());
+        } else if &old_elders_info != self.section.elders_info() {
+            // Whenever there is an elders change, casting a round of joins_allowed vote to sync.
+            commands.extend(self.vote(Vote::JoinsAllowed(self.joins_allowed))?);
         }
 
         Ok(commands)
@@ -1715,6 +1731,14 @@ impl Approved {
         Ok(Some(command))
     }
 
+    pub fn set_joins_allowed(&mut self, joins_allowed: bool) -> Result<Vec<Command>> {
+        let mut commands = Vec::new();
+        if self.is_elder() && joins_allowed != self.joins_allowed {
+            commands.extend(self.vote(Vote::JoinsAllowed(joins_allowed))?);
+        }
+        Ok(commands)
+    }
+
     pub fn send_user_message(
         &mut self,
         src: SrcLocation,

src/routing/command.rs

@@ -81,6 +81,8 @@ pub(crate) enum Command {
         /// Message receiver to pass to the bootstrap task.
         message_rx: mpsc::Receiver<(Message, SocketAddr)>,
     },
+    /// Attempt to set JoinsAllowed flag.
+    SetJoinsAllowed(bool),
 }
 
 impl Command {
@@ -179,6 +181,10 @@ impl Debug for Command {
                 .field("bootstrap_addrs", bootstrap_addrs)
                 .field("details", details)
                 .finish(),
+            Self::SetJoinsAllowed(joins_allowed) => f
+                .debug_tuple("SetJoinsAllowed")
+                .field(joins_allowed)
+                .finish(),
         }
     }
 }

src/routing/mod.rs

@@ -137,6 +137,12 @@ impl Routing {
         Ok((routing, event_stream))
     }
 
+    /// Sets the JoinsAllowed flag.
+    pub async fn set_joins_allowed(&self, joins_allowed: bool) -> Result<()> {
+        let command = Command::SetJoinsAllowed(joins_allowed);
+        self.stage.clone().handle_commands(command).await
+    }
+
     /// Returns the current age of this node.
     pub async fn age(&self) -> u8 {
         self.stage.state.lock().await.node().age

src/routing/stage.rs

@@ -124,6 +124,9 @@ impl Stage {
                     self.handle_relocate(bootstrap_addrs, details, message_rx)
                         .await
                 }
+                Command::SetJoinsAllowed(joins_allowed) => {
+                    self.state.lock().await.set_joins_allowed(joins_allowed)
+                }
             }
         }
         .await;