diff --git a/packages/controller/src/ControllerRouter.ts b/packages/controller/src/ControllerRouter.ts
index c7337611..51e972df 100644
--- a/packages/controller/src/ControllerRouter.ts
+++ b/packages/controller/src/ControllerRouter.ts
@@ -21,7 +21,7 @@ export default class ControllerRouter {
 	 */
 	forwardMessage(
 		origin: ControlConnection | HostConnection,
-		message: lib.MessageSrcDst,
+		message: lib.MessageRoutable,
 		hasFallback: boolean
 	): boolean {
 		if (!["request", "response", "responseError", "event"].includes(message.type)) {
@@ -95,7 +95,7 @@ export default class ControllerRouter {
 
 	broadcastMessage(
 		origin: lib.Link,
-		message: lib.MessageSrcDst,
+		message: lib.MessageRoutable,
 	) {
 		let dst = message.dst;
 		if (message.type !== "event") {
@@ -118,7 +118,7 @@ export default class ControllerRouter {
 	}
 
 	warnUnrouted(
-		message: lib.MessageSrcDst,
+		message: lib.MessageRoutable,
 		msg: string
 	) {
 		let dst = message.dst;
diff --git a/packages/controller/src/HostConnection.ts b/packages/controller/src/HostConnection.ts
index 9f820595..013d3c9e 100644
--- a/packages/controller/src/HostConnection.ts
+++ b/packages/controller/src/HostConnection.ts
@@ -84,7 +84,7 @@ export default class HostConnection extends BaseConnection {
 		this.handle(lib.InstancePlayerUpdateEvent, this.handleInstancePlayerUpdateEvent.bind(this));
 	}
 
-	validateIngress(message: lib.MessageSrcDst) {
+	validateIngress(message: lib.MessageRoutable) {
 		let origin = this.connector.dst;
 		switch (message.src.type) {
 			case lib.Address.control:
diff --git a/packages/lib/src/data/messages_core.ts b/packages/lib/src/data/messages_core.ts
index 62df2711..73ffceea 100644
--- a/packages/lib/src/data/messages_core.ts
+++ b/packages/lib/src/data/messages_core.ts
@@ -172,7 +172,7 @@ export class Message {
 	}
 }
 
-export type MessageSrcDst = MessageRequest | MessageResponse | MessageResponseError | MessageEvent;
+export type MessageRoutable = MessageRequest | MessageResponse | MessageResponseError | MessageEvent;
 
 export class HelloData {
 	constructor(
diff --git a/packages/lib/src/link/connectors.ts b/packages/lib/src/link/connectors.ts
index 742b5c30..b8960f42 100644
--- a/packages/lib/src/link/connectors.ts
+++ b/packages/lib/src/link/connectors.ts
@@ -81,12 +81,6 @@ export abstract class BaseConnector extends events.EventEmitter {
 }
 
 type ConnectorState = "closed" | "connecting" | "connected" | "resuming";
-type ReliableMessages =
-	| libData.MessageRequest
-	| libData.MessageResponse
-	| libData.MessageResponseError
-	| libData.MessageEvent
-;
 
 /**
  * Base connector for links
@@ -102,7 +96,7 @@ export abstract class WebSocketBaseConnector extends BaseConnector {
 	_heartbeatId: ReturnType<typeof setInterval> | null = null;
 	_heartbeatInterval: number | null = null;
 	_lastReceivedSeq = undefined;
-	_sendBuffer: (ReliableMessages)[] = [];
+	_sendBuffer: (libData.MessageRoutable)[] = [];
 
 	constructor(src: libData.Address, dst: libData.Address) {
 		super(src, dst);
@@ -249,7 +243,7 @@ export abstract class WebSocketBaseConnector extends BaseConnector {
 	 *
 	 * @param message - Message to send.
 	 */
-	send(message: ReliableMessages) {
+	send(message: libData.MessageRoutable) {
 		if (!["connected", "resuming"].includes(this._state)) {
 			throw new libErrors.SessionLost("No session");
 		}
diff --git a/packages/lib/src/link/link.ts b/packages/lib/src/link/link.ts
index 99c55037..46cc267d 100644
--- a/packages/lib/src/link/link.ts
+++ b/packages/lib/src/link/link.ts
@@ -8,7 +8,7 @@ import { BaseConnector, WebSocketBaseConnector } from "./connectors";
 import { strict as assert } from "assert";
 import type { PluginInfo } from "../plugin";
 import type { User } from "../users";
-import type { AddressType, JSONDeserialisable, Message, MessageRequest, MessageEvent } from "../data";
+import type { AddressType, JSONDeserialisable, MessageRoutable, MessageRequest, MessageEvent } from "../data";
 
 export interface Request<Req, Res> {
 	constructor: Partial<JSONDeserialisable<Request<Req, Res>>> & {
@@ -71,7 +71,7 @@ export type RequestHandler<Req, Res> = (request: Req, src: libData.Address, dst:
 export type EventHandler<T> = (event: T, src: libData.Address, dst: libData.Address) => Promise<void>;
 
 interface Router {
-	forwardMessage(origin: Link, message: Message, fallback: boolean): boolean,
+	forwardMessage(origin: Link, message: MessageRoutable, fallback: boolean): boolean,
 }
 
 // Some definitions for the terminology used here:
@@ -166,7 +166,7 @@ export class Link {
 	 * @throws {libErrors.InvalidMessage} if the message is invalid or not handled.
 	 */
 	_processMessage(
-		message: libData.MessageRequest | libData.MessageResponse | libData.MessageResponseError | libData.MessageEvent
+		message: MessageRoutable
 	) {
 		if (!["request", "response", "responseError", "event"].includes(message.type)) {
 			throw new libErrors.InvalidMessage(`Unhandled message type ${message.type}`);
@@ -175,7 +175,10 @@ export class Link {
 		let entry = this._validateMessage(message);
 		if (entry && this.connector.dst.type === libData.Address.control) {
 			try {
-				this.validatePermission(message, entry); // Somewhat hacky, defined in ControlConnection
+				this.validatePermission(
+					message as libData.MessageRequest | libData.MessageEvent,
+					entry
+				); // Somewhat hacky, defined in ControlConnection
 			} catch (err) {
 				if (err instanceof libErrors.PermissionError) {
 					return;
@@ -229,10 +232,10 @@ export class Link {
 	 * @param message - Message to check.
 	 * @throws {libErrors.InvalidMessage} if the message is invalid.
 	 */
-	validateIngress(message: libData.Message) { }
+	validateIngress(message: MessageRoutable) { }
 
 	_validateMessage(
-		message: libData.MessageRequest | libData.MessageResponse | libData.MessageResponseError | libData.MessageEvent
+		message: MessageRoutable
 	) {
 		try {
 			if (message.src.type === libData.Address.broadcast) {
@@ -307,9 +310,9 @@ export class Link {
 	 * @param entry - Request or Event entry for this Message.
 	 * @throws {libErrors.PermissionError} if unauthorized.
 	 */
-	validatePermission(message: libData.Message, entry: RequestEntry | EventEntry) { }
+	validatePermission(message: libData.MessageRequest | libData.MessageEvent, entry: RequestEntry | EventEntry) { }
 
-	_routeMessage(message: libData.Message, entry?: RequestEntry | EventEntry) {
+	_routeMessage(message: MessageRoutable, entry?: RequestEntry | EventEntry) {
 		if (!this.router) {
 			let err = new libErrors.InvalidMessage(
 				`Received message addressed to ${(message as libData.MessageRequest).dst} but this link `+