fix(backend): fix #16994 by approach 6 (#17005)

* fix(backend): narrow down trustproxy default value and enhance documentation on how to configure it

* Update Changelog

* indent [ci skip]

* Update CHANGELOG.md [ci skip]

* add cloudflare specific example

* Update .config/example.yml

Co-authored-by: anatawa12 <anatawa12@icloud.com>

* fix: productionでIPレートリミットされる際にlocalhostからリクエストが来たらログを残すように

* fix: wrong condition

* fix: use own logger for signin api

* flip configuration

* fix

* fix [ci skip]

* fix: wrong message [ci skip]

* fix: どこがおかしいか明記 [ci skip]

---------

Co-authored-by: anatawa12 <anatawa12@icloud.com>

packages/backend/src/config.ts

@@ -30,6 +30,7 @@ type Source = {
 	socket?: string;
 	trustProxy?: FastifyServerOptions['trustProxy'];
 	chmodSocket?: string;
+	enableIpRateLimit?: boolean;
 	disableHsts?: boolean;
 	db: {
 		host: string;
@@ -120,8 +121,9 @@ export type Config = {
 	url: string;
 	port: number;
 	socket: string | undefined;
-	trustProxy: FastifyServerOptions['trustProxy'];
+	trustProxy: NonNullable<FastifyServerOptions['trustProxy']>;
 	chmodSocket: string | undefined;
+	enableIpRateLimit: boolean;
 	disableHsts: boolean | undefined;
 	db: {
 		host: string;
@@ -263,9 +265,17 @@ export function loadConfig(): Config {
 		url: url.origin,
 		port: config.port ?? parseInt(process.env.PORT ?? '', 10),
 		socket: config.socket,
-		trustProxy: config.trustProxy,
+		trustProxy: config.trustProxy ?? [
+			'10.0.0.0/8',
+			'172.16.0.0/12',
+			'192.168.0.0/16',
+			'127.0.0.1/32',
+			'::1/128',
+			'fc00::/7',
+		],
 		chmodSocket: config.chmodSocket,
 		disableHsts: config.disableHsts,
+		enableIpRateLimit: config.enableIpRateLimit ?? true,
 		host,
 		hostname,
 		scheme,