first version

Author: ccloli

.eslintrc.json

@@ -0,0 +1,29 @@
+{
+    "env": {
+        "es6": true,
+        "node": true
+    },
+    "extends": "eslint:recommended",
+    "rules": {
+        "indent": [
+            "error",
+            "tab",
+            {
+                "SwitchCase": 1
+            }
+        ],
+        "linebreak-style": [
+            "error",
+            "windows"
+        ],
+        "quotes": [
+            "error",
+            "single"
+        ],
+        "semi": [
+            "error",
+            "always"
+        ],
+        "no-console": "off"
+    }
+}

.gitignore

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+node_modules/
+rules/*
+!rules/.gitkeep
+config.json
+*.bak
+*.bak.*

common/consts.js

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+const { reverseFill } = require('./utils');
+
+const DNSTYPE = reverseFill({
+	A: 1,
+	NS: 2,
+	MD: 3,
+	MF: 4,
+	CNAME: 5,
+	SOA: 6,
+	MB: 7,
+	MG: 8,
+	MR: 9,
+	NULL: 10,
+	WKS: 11,
+	PTR: 12,
+	HINFO: 13,
+	MINFO: 14,
+	MX: 15,
+	TXT: 16,
+	RP: 17,
+	AFSDB: 18,
+	X25: 19,
+	ISDN: 20,
+	RT: 21,
+	NSAP: 22,
+	'NSAP-PTR': 23,
+	SIG: 24,
+	KEY: 25,
+	PX: 26,
+	GPOS: 27,
+	AAAA: 28,
+	LOC: 29,
+	NXT: 30,
+	EID: 31,
+	NB: 32,
+	NIMLOC: 32,
+	SRV: 33,
+	NBSTAT: 33,
+	ATMA: 34,
+	NAPTR: 35,
+	KX: 36,
+	CERT: 37,
+	A6: 38,
+	DNAME: 39,
+	SINK: 40,
+	OPT: 41,
+	APL: 42,
+	DS: 43,
+	SSHFP: 44,
+	IPSECKEY: 45,
+	RRSIG: 46,
+	NSEC: 47,
+	DNSKEY: 48,
+	DHCID: 49,
+	NSEC3: 50,
+	NSEC3PARAM: 51,
+	TLSA: 52,
+	HIP: 55,
+	CDS: 59,
+	CDNSKEY: 60,
+	OPENPGPKEY: 61,
+	SPF: 99,
+	UINFO: 100,
+	UID: 101,
+	GID: 102,
+	UNSPEC: 103,
+	TKEY: 249,
+	TSIG: 250,
+	IXFR: 251,
+	AXFR: 252,
+	MAILB: 253,
+	MAILA: 254,
+	ANY: 255,
+	URI: 256,
+	CAA: 257,
+	TA: 32768,
+	DLV: 32769
+});
+
+const DNSCLASS = reverseFill({
+	IN: 1,
+	CS: 2,
+	CH: 3,
+	HS: 4
+});
+
+module.exports = {
+	DNSTYPE,
+	DNSCLASS
+};

common/convert.js

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+const udpPacketToTcpPacket = (data) => {
+	const length = data.byteLength;
+	if (length > 512) {
+		console.warn(`*UDP->TCP* Packet size is ${length}, which is larger than 512, request data maybe invalid.`);
+	}
+	return Buffer.concat([Buffer.from([length >> 8, length & 255]), data]);
+};
+
+const tcpPacketToUdpPacket = (data, tc = false) => {
+	const length = (data[0] << 8) + data[1];
+	data = data.slice(2);
+	const actualLength = data.byteLength;
+	if (actualLength !== length) {
+		console.warn(`*TCP->UDP* Packet size doesn't match, expected ${length} but got ${actualLength}, request data maybe invalid.`);
+	}
+	if (actualLength > 512) {
+		if (tc) {
+			data = data.split(0, 512);
+			// set TC to 1
+			data[3] |= 4;
+			console.warn('*TCP->UDP* Packet size is larger than 512 bytes, data is truncated and TC is set to true.');
+		}
+		else {
+			console.warn('*TCP->UDP* Packet size is larger than 512 bytes, data is not truncated but response data maybe not acceptable.');
+		}
+	}
+	return data;
+};
+
+module.exports = {
+	udpPacketToTcpPacket,
+	tcpPacketToUdpPacket
+};

common/load-config.js

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+const fs = require('fs');
+const { parseServer } = require('./utils');
+
+const defaultConfig = {
+	tcp: {
+		enable: false,
+		host: '::',
+		port: 53
+	},
+	udp: {
+		enable: false,
+		host: '::',
+		port: 53
+	},
+	servers: {
+		default: {
+			host: '8.8.8.8',
+			port: '53',
+			type: 'udp'
+		}
+	},
+	rules: []
+};
+
+const loadConfig = (path) => {
+	// require() cannot be reloaded until restart
+	// const config = require(path);
+	const config = JSON.parse(fs.readFileSync(path, 'utf8'));
+
+	// only merge the first level and second level config
+	const result = Object.assign({}, defaultConfig, config);
+	Object.keys(defaultConfig).forEach(key => {
+		if (typeof defaultConfig[key] !== 'object' || defaultConfig[key] instanceof Array) {
+			return;
+		}
+		result[key] = Object.assign({}, defaultConfig[key], result[key]);
+	});
+
+	// parse servers
+	const { servers, rules } = result;
+	Object.keys(servers).forEach(key => {
+		servers[key] = parseServer(servers[key]);
+	});
+	for (let rule of rules) {
+		const { server } = rule;
+		if (server) {
+			if (typeof server === 'string' && servers[server]) {
+				rule.server = servers[server];
+			}
+			else {
+				rule.server = parseServer(server);
+			}
+		}
+	}
+
+	return result;
+};
+
+module.exports = loadConfig;