110 lines
3.0 KiB
TypeScript
110 lines
3.0 KiB
TypeScript
import { field, logger } from "@coder/logger";
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import * as http from "http";
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//@ts-ignore
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import * as named from "node-named";
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import * as ip from "ip-address";
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import { words, wordKeys } from "./words";
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import * as dgram from "dgram";
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const oldCreate = dgram.createSocket;
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// tslint:disable-next-line:no-any
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(<any>dgram).createSocket = (_: any, callback: any): dgram.Socket => {
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return oldCreate("udp4", callback);
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};
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interface DnsQuery {
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name(): string;
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// tslint:disable-next-line:no-any
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addAnswer(domain: string, target: any, ttl: number): void;
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}
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const dnsServer: {
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listen(port: number, host: string, callback: () => void): void;
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on(event: "query", callback: (query: DnsQuery) => void): void;
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send(query: DnsQuery): void;
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} = named.createServer();
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const isDev = process.env.NODE_ENV !== "production";
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const dnsPort = isDev ? 9999 : 53;
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dnsServer.listen(dnsPort, "0.0.0.0", () => {
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logger.info("DNS server started", field("port", dnsPort));
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});
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dnsServer.on("query", (query) => {
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const domain = query.name();
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const reqParts = domain.split(".");
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if (reqParts.length < 2) {
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dnsServer.send(query);
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logger.info("Invalid request", field("request", domain));
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return;
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}
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const allWords = reqParts.shift()!;
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if (allWords.length > 16) {
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dnsServer.send(query);
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logger.info("Invalid request", field("request", domain));
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return;
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}
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const wordParts = allWords.split(/(?=[A-Z])/);
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const ipParts: string[] = [];
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// Should be left with HowAreYouNow
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for (let i = 0; i < wordParts.length; i++) {
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const part = wordParts[i];
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if (part.length > 4) {
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dnsServer.send(query);
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logger.info("Words too long", field("request", domain));
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return;
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}
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const ipPart = words[part.toLowerCase()];
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if (typeof ipPart === "undefined") {
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dnsServer.send(query);
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logger.info("Word not found in index", field("part", part), field("request", domain));
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return;
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}
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ipParts.push(ipPart.toString());
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}
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const address = new ip.Address4(ipParts.join("."));
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if (address.isValid()) {
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logger.info("Responded with valid address query", field("address", address.address), field("request", domain));
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query.addAnswer(domain, new named.ARecord(address.address), 99999);
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} else {
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logger.warn("Received invalid request", field("request", domain));
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}
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dnsServer.send(query);
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});
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const httpServer = http.createServer((request, response) => {
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const remoteAddr = request.connection.remoteAddress;
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if (!remoteAddr) {
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response.writeHead(422);
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response.end();
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return;
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}
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const hostHeader = request.headers.host;
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if (!hostHeader) {
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response.writeHead(422);
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response.end();
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return;
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}
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const host = remoteAddr.split(".").map(p => wordKeys[Number.parseInt(p, 10)]).map(s => s.charAt(0).toUpperCase() + s.slice(1)).join("");
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logger.info("Resolved host", field("remote-addr", remoteAddr), field("host", host));
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response.writeHead(200);
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response.write(`${host}.${hostHeader}`);
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response.end();
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});
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const httpPort = isDev ? 3000 : 80;
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httpServer.listen(httpPort, "0.0.0.0", () => {
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logger.info("HTTP server started", field("port", httpPort));
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});
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