From 1091f9c3c28ff731f919b23cbe99d294797cbf2b Mon Sep 17 00:00:00 2001
From: Starbeamrainbowlabs <sbrl@starbeamrainbowlabs.com>
Date: Sun, 9 Jan 2022 20:28:58 +0000
Subject: [PATCH] Exchange peerlists

---
 src/lib/agent/Agent.mjs       | 53 +++++++++++++++++++++++++++++++++++
 src/lib/agent/Peer.mjs        | 13 +++------
 src/lib/agent/PeerServer.mjs  |  6 ++--
 src/lib/core/ErrorWrapper.mjs |  4 +++
 4 files changed, 65 insertions(+), 11 deletions(-)

diff --git a/src/lib/agent/Agent.mjs b/src/lib/agent/Agent.mjs
index 5694e79..3373ce8 100644
--- a/src/lib/agent/Agent.mjs
+++ b/src/lib/agent/Agent.mjs
@@ -34,16 +34,34 @@ class Agent {
 	}
 	
 	async init() {
+		///
+		// 1: Create our local environment
+		///
 		/** Our peer id - calculated automatically from the system's uuid */
 		this.peer_id = await hostuuid(this.config.net.port);
 		this.peer_name = os.hostname();
 		
+		
+		///
+		// 2: Create the peer server
+		///
 		this.server = new PeerServer(
 			this.peer_id,
 			await this.find_secret()
 		);
 		this.server.retries = this.config.net.peer_retries;
 		
+		
+		///
+		// 3: Attach message handling listeners
+		///
+		this.server.on("message-peerlist-request", this.__send_peer_list.bind(this));
+		this.server.on("message-peerlist-response", this.__handle_peer_list.bind(this));
+		
+		
+		///
+		// 4: Start listening
+		///
 		l.log(`Starting peer listener....`);
 		await this.server.listen(
 			this.config.net.port,
@@ -51,6 +69,10 @@ class Agent {
 		);
 		l.log(`Listening on ${this.config.net.bind_address}:${this.config.net.port}`);
 		
+		
+		///
+		// 5: Add initial peers to kick things off
+		///
 		await this.server.add_peers(...this.config.peers.map(
 			peer => parse_peer_name(peer)
 		));
@@ -58,6 +80,37 @@ class Agent {
 		l.log(`Added ${this.server.peers().length} / ${this.config.peers.length} initial peers`);
 		if(this.config.peers.length < 1)
 			l.warn(`No initial peers were specified! It's recommended that you specify at least 1 on every host.`);
+		
+		// Ask for more peers
+		await this.server.broadcast("peerlist-request", {});
+	}
+	
+	/**
+	 * Sends a list of known peers to the given peer.
+ 	 * @param	{Peer}		peer	The peer to send the list to.
+	 * @return	{Promise}	A Promise that resolves whent he message has been sent.
+	 */
+	async __send_peer_list(peer, _msg) {
+		l.log(`Sending peer list to ${peer.id_short}`);
+		await peer.send("peerlist-response", {
+			peers: this.server.peers()
+		});
+	}
+	
+	async __handle_peer_list(peer, msg) {
+		l.log(`Received peer list from ${peer.id_short}`);
+		if(!(msg.peers instanceof Array)) {
+			l.warn(`Encountered invalid peer list message from peer ${peer.id_short}.`);
+			return false;
+		}
+		let peerids_connected = this.server.peers().map(el => el.id);
+		let new_peers = await this.server.add_peers(...msg.peers
+				.filter(el => !peerids_connected.includes(el.id) && el.id !== this.peer_id)
+				.map(el => { return { address: el.listening_address, port: el.listening_port }; }));
+		if(new_peers.length > 0)
+			l.log(`Connected to ${new_peers.length} / ${msg.peers.length} peers from peerlist sent by ${peer.id_short}`);
+		else
+			l.log(`No new peers in peerlist sent by ${peer.id_short}`);
 	}
 }
 
diff --git a/src/lib/agent/Peer.mjs b/src/lib/agent/Peer.mjs
index 67ed86b..474f0f4 100644
--- a/src/lib/agent/Peer.mjs
+++ b/src/lib/agent/Peer.mjs
@@ -33,13 +33,6 @@ class Peer extends EventEmitter {
 		 */
 		this.connection = connection;
 		
-		/**
-		 * A list of other peers known to this peer.
-		 * May or may not actually be up to date.
-		 * @type {{address:string,port:number}[]}
-		 */
-		this.known_peers = [];
-		
 		// If a message with the event name "end" is received, close our side
 		// of the connection
 		this.once(`message-end`, this.destroy);
@@ -88,7 +81,8 @@ class Peer extends EventEmitter {
 	 */
 	__handle_hello(msg) {
 		this.id = msg.id;
-		this.known_peers = msg.peers;
+		this.listening_address = msg.listening_address;
+		this.listening_port = msg.listening_port;
 		
 		if(this.id === this.server.our_id) {
 			l.warn(`Our id (${this.server.our_id}) is equal to that of the remote (${this.id}), killing connection`);
@@ -111,7 +105,8 @@ class Peer extends EventEmitter {
 	async __send_hello() {
 		await this.send("hello", {
 			id: this.server.our_id,
-			peers: this.server.peers()
+			listening_address: this.server.host,
+			listening_port: this.server.port
 		});
 	}
 	
diff --git a/src/lib/agent/PeerServer.mjs b/src/lib/agent/PeerServer.mjs
index f56e002..41e9cbc 100644
--- a/src/lib/agent/PeerServer.mjs
+++ b/src/lib/agent/PeerServer.mjs
@@ -108,7 +108,9 @@ class PeerServer extends EventEmitter {
 		return this.connected_peers.map(peer => { return {
 			address: peer.address,
 			port: peer.port,
-			id: peer.id
+			id: peer.id,
+			listening_address: peer.listening_address,
+			listening_port: peer.listening_port
 		}}).filter(el => typeof el.address === "string" && typeof el.port === "number");
 	}
 	
@@ -153,7 +155,7 @@ class PeerServer extends EventEmitter {
 				), {
 					retries: this.retries,
 					onFailedAttempt: (error) => {
-						switch(error instanceof ErrorWrapper ? error.inner_exception.code : error.code) {
+						switch(error.code) {
 							case "ECONNREFUSED":
 								l.error(`Failed to connect to peer at ${new_peer.address}:${new_peer.port}.`);
 								break;
diff --git a/src/lib/core/ErrorWrapper.mjs b/src/lib/core/ErrorWrapper.mjs
index 27fb432..5f8128e 100644
--- a/src/lib/core/ErrorWrapper.mjs
+++ b/src/lib/core/ErrorWrapper.mjs
@@ -1,6 +1,10 @@
 "use strict";
 
 class ErrorWrapper extends Error {
+	get code() {
+		return this.inner_exception.code;
+	}
+	
 	constructor(message, inner_exception) {
 		super(message);
 		this.inner_exception = inner_exception;