feat(p2p): I added a connection rotation and limited max connections

Implement connection rotation to periodically close oldest connections when exceeding half of MAX_CONNECTIONS. Also enforce MAX_CONNECTIONS limit by rejecting new connections when limit is reached (32). This improves network stability and resource management.

I also changed max relay hops from 3 to 2.

With the connection rotation I think these more conservative numbers should suffice and save on resources.

src/config/constants.js

@@ -15,9 +15,11 @@ const POW_PREFIX = "0000";
 
 const MAX_PEERS = parseInt(process.env.MAX_PEERS) || 10000;
 const MAX_MESSAGE_SIZE = 2048;
-const MAX_RELAY_HOPS = 3;
+const MAX_RELAY_HOPS = 2;
+const MAX_CONNECTIONS = 32;
 
 const HEARTBEAT_INTERVAL = 5000;
+const CONNECTION_ROTATION_INTERVAL = 30000;
 const PEER_TIMEOUT = 15000;
 const BROADCAST_THROTTLE = 1000;
 const DIAGNOSTICS_INTERVAL = 10000;
@@ -30,7 +32,9 @@ module.exports = {
     MAX_PEERS,
     MAX_MESSAGE_SIZE,
     MAX_RELAY_HOPS,
+    MAX_CONNECTIONS,
     HEARTBEAT_INTERVAL,
+    CONNECTION_ROTATION_INTERVAL,
     PEER_TIMEOUT,
     BROADCAST_THROTTLE,
     DIAGNOSTICS_INTERVAL,

src/p2p/swarm.js

@@ -1,6 +1,6 @@
 const Hyperswarm = require("hyperswarm");
 const { signMessage } = require("../core/security");
-const { TOPIC, TOPIC_NAME, HEARTBEAT_INTERVAL } = require("../config/constants");
+const { TOPIC, TOPIC_NAME, HEARTBEAT_INTERVAL, MAX_CONNECTIONS, CONNECTION_ROTATION_INTERVAL } = require("../config/constants");
 
 class SwarmManager {
     constructor(identity, peerManager, diagnostics, messageHandler, relayFn, broadcastFn) {
@@ -13,6 +13,7 @@ class SwarmManager {
 
         this.swarm = new Hyperswarm();
         this.heartbeatInterval = null;
+        this.rotationInterval = null;
     }
 
     async start() {
@@ -22,9 +23,17 @@ class SwarmManager {
         await discovery.flushed();
 
         this.startHeartbeat();
+        this.startRotation();
     }
 
     handleConnection(socket) {
+        if (this.swarm.connections.size > MAX_CONNECTIONS) {
+            socket.destroy();
+            return;
+        }
+
+        socket.connectedAt = Date.now();
+
         const sig = signMessage(`seq:${this.peerManager.getSeq()}`, this.identity.privateKey);
         const hello = JSON.stringify({
             type: "HEARTBEAT",
@@ -88,6 +97,23 @@ class SwarmManager {
         }, HEARTBEAT_INTERVAL);
     }
 
+    startRotation() {
+        this.rotationInterval = setInterval(() => {
+            if (this.swarm.connections.size < MAX_CONNECTIONS / 2) return;
+
+            let oldest = null;
+            for (const socket of this.swarm.connections) {
+                if (!oldest || socket.connectedAt < oldest.connectedAt) {
+                    oldest = socket;
+                }
+            }
+
+            if (oldest) {
+                oldest.destroy();
+            }
+        }, CONNECTION_ROTATION_INTERVAL);
+    }
+
     shutdown() {
         const sig = signMessage(`type:LEAVE:${this.identity.id}`, this.identity.privateKey);
         const goodbye = JSON.stringify({
@@ -105,6 +131,10 @@ class SwarmManager {
             clearInterval(this.heartbeatInterval);
         }
 
+        if (this.rotationInterval) {
+            clearInterval(this.rotationInterval);
+        }
+
         setTimeout(() => {
             process.exit(0);
         }, 500);