From ebc899c47fce77d05dfe50e64807c5baa3670b76 Mon Sep 17 00:00:00 2001
From: MeiMei <30769358+mei23@users.noreply.github.com>
Date: Wed, 9 Jan 2019 15:17:54 +0900
Subject: [PATCH] Use cached and asynchronous DNS resolver for AP delivery
 (#3859)

---
 package.json                      |  4 +++-
 src/remote/activitypub/request.ts | 33 ++++++++++++++++++++++++++++---
 2 files changed, 33 insertions(+), 4 deletions(-)

diff --git a/package.json b/package.json
index 5f9d96595..fb5d5144c 100644
--- a/package.json
+++ b/package.json
@@ -62,7 +62,7 @@
 		"@types/mocha": "5.2.5",
 		"@types/mongodb": "3.1.14",
 		"@types/ms": "0.7.30",
-		"@types/node": "10.12.10",
+		"@types/node": "10.12.18",
 		"@types/nodemailer": "4.6.5",
 		"@types/oauth": "0.9.1",
 		"@types/parsimmon": "1.10.0",
@@ -156,6 +156,7 @@
 		"koa-views": "6.1.4",
 		"langmap": "0.0.16",
 		"loader-utils": "1.2.3",
+		"lookup-dns-cache": "2.1.0",
 		"minio": "7.0.2",
 		"mkdirp": "0.5.1",
 		"mocha": "5.2.0",
@@ -176,6 +177,7 @@
 		"portscanner": "2.2.0",
 		"postcss-loader": "3.0.0",
 		"progress-bar-webpack-plugin": "1.11.0",
+		"promise-any": "0.2.0",
 		"promise-limit": "2.7.0",
 		"promise-sequential": "1.1.1",
 		"pug": "2.0.3",
diff --git a/src/remote/activitypub/request.ts b/src/remote/activitypub/request.ts
index 68c53e0c6..d98e36b3d 100644
--- a/src/remote/activitypub/request.ts
+++ b/src/remote/activitypub/request.ts
@@ -3,6 +3,8 @@ const { sign } = require('http-signature');
 import { URL } from 'url';
 import * as debug from 'debug';
 const crypto = require('crypto');
+const { lookup } = require('lookup-dns-cache');
+const promiseAny = require('promise-any');
 
 import config from '../../config';
 import { ILocalUser } from '../../models/user';
@@ -10,12 +12,12 @@ import { publishApLogStream } from '../../stream';
 
 const log = debug('misskey:activitypub:deliver');
 
-export default (user: ILocalUser, url: string, object: any) => new Promise((resolve, reject) => {
+export default (user: ILocalUser, url: string, object: any) => new Promise(async (resolve, reject) => {
 	log(`--> ${url}`);
 
 	const timeout = 10 * 1000;
 
-	const { protocol, hostname, port, pathname, search } = new URL(url);
+	const { protocol, host, hostname, port, pathname, search } = new URL(url);
 
 	const data = JSON.stringify(object);
 
@@ -23,14 +25,19 @@ export default (user: ILocalUser, url: string, object: any) => new Promise((reso
 	sha256.update(data);
 	const hash = sha256.digest('base64');
 
+	const addr = await resolveAddr(hostname).catch(e => reject(e));
+	if (!addr) return;
+
 	const req = request({
 		protocol,
-		hostname,
+		hostname: addr,
+		setHost: false,
 		port,
 		method: 'POST',
 		path: pathname + search,
 		timeout,
 		headers: {
+			'Host': host,
 			'User-Agent': config.user_agent,
 			'Content-Type': 'application/activity+json',
 			'Digest': `SHA-256=${hash}`
@@ -75,3 +82,23 @@ export default (user: ILocalUser, url: string, object: any) => new Promise((reso
 	});
 	//#endregion
 });
+
+/**
+ * Resolve host (with cached, asynchrony)
+ */
+async function resolveAddr(domain: string) {
+	// v4/v6で先に取得できた方を採用する
+	return await promiseAny([
+		resolveAddrInner(domain, { ipv6: false }),
+		resolveAddrInner(domain, { ipv6: true  })
+	]);
+}
+
+function resolveAddrInner(domain: string, options = { }): Promise<string> {
+	return new Promise((res, rej) => {
+		lookup(domain, options, (error: any, address: string) => {
+			if (error) return rej(error);
+			return res(address);
+		});
+	});
+}