♻️ Split dns resolver into two files
This commit is contained in:
parent
fab92b078b
commit
908c4871ed
GPG key ID:
62993C4BB4D86F24
4 changed files with 197 additions and 193 deletions
192
src/cdn/dns.ts
192
src/cdn/dns.ts
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@ -1,192 +0,0 @@
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/* --- DNS resolver for the CDN storing SWTOR's patch files ---
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| The SWTOR launcher first connects to cdn-patch.swtor.com,
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| there the traffic is split onto Akamai and Level3, and
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| distributed to local points of presence.
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| The master files appear to be stored on 159.153.92.51, and
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| all CDNs are synchronized with that source.
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|
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| > cdn-patch.swtor.com
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| -> gslb-patch.swtor.biowareonline.net
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| -> cdn-patch.swtor.com.edgesuite.net (Akamai)
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| | -> a56.d.akamai.net
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| | -> 2.21.74.90
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| | -> 2.21.74.98
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| -> cdn-patch.swtor.com.c.footprint.net (Level3)
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| -> eu.lvlt.cdn.ea.com.c.footprint.net (Europe)
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| | -> 8.12.207.125
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| | -> 8.253.37.126
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| -> na.lvlt.cdn.ea.com.c.footprint.net (US)
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| -> 205.128.74.252
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| -> 4.23.36.253
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| -> 192.221.105.254
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|
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| Examples:
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| - http://cdn-patch.swtor.com/patch/assets_swtor_main/assets_swtor_main_-1to0.solidpkg
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| - http://159.153.92.51/patch/assets_swtor_main/assets_swtor_main_-1to0.solidpkg
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*/
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import { exec} from 'child_process';
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import * as dns from 'dns';
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import { IDnsResult, IServerEntry } from '../interfaces/IDnsResult';
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//Time when this script started, for delta time calculations
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const startTime = Date.now();
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let lastUpdate = 0;
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//List of servers, sorted by reliability
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let servers: IServerEntry[] = [];
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//the master source is included by default
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servers.push({ ip: '159.153.92.51', type: 'master', lastSeen: Infinity, weight: Infinity });
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//TODO: send e-mail with the error
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const assert = (cond: boolean) => { if (!cond) { console.warn('Assert failed'); } };
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//Looks up the given domain and returns a list of IP addresses, along with their time-to-live
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async function resolveDns(domain: string): Promise<IDnsResult[]> {
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return new Promise((resolve) => {
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//check given string for correctness to prevent injection attacks
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if (!domain.match(/^[a-z0-9]+([-.]{1}[a-z0-9]+)*\.[a-z]{2,3}$/)) { return resolve([]); }
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//Check Level3/North_America separetely
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if (domain !== 'cdn-patch.swtor.com') {
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dns.resolve4(domain, { ttl: true }, (err, result) => {
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return resolve(result.map(({ address, ttl }) => ({ address, ttl, type: 'level3-us' as IDnsResult['type'] })));
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});
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} else {
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//Use bash so we get more information.
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//Also do plenty of asserts to ensure that overall CDN structure has stayed unchanged, and TODO send e-mail if it's different (max. once per hour)
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exec('dig +noall +answer "cdn-patch.swtor.com"', { timeout: 10000 }, (error, stdout) => {
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//check for error
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assert(!error);
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if (error) {
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return resolve([]);
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}
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const data = stdout.trim().split('\n').map((line) => line.split(/\t| /));
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//Verify output
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assert(data.length > 3);
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data.forEach((dataLine) => assert(dataLine.length === 5));
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assert(data[0][0] === 'cdn-patch.swtor.com.');
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assert(data[0][1].match(/^[0-9]{1,3}$/) !== null); //at least up to 598
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assert(data[0][2] === 'IN');
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assert(data[0][3] === 'CNAME');
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assert(data[0][4] === 'gslb-patch.swtor.biowareonline.net.');
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assert(data[1][0] === 'gslb-patch.swtor.biowareonline.net.');
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assert(data[1][1].match(/^[0-9]{1,2}$/) !== null); //up to 60 seconds
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assert(data[1][2] === 'IN');
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assert(data[1][3] === 'CNAME');
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assert(data[1][4] === 'cdn-patch.swtor.com.edgesuite.net.' || data[1][4] === 'cdn-patch.swtor.com.c.footprint.net.');
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assert(data[2][0] === data[1][4]);
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assert(data[2][1].match(/^[0-9]{1,5}$/) !== null); //at least up to 15092 if Akamai, at least up to 627 if Level3
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assert(data[2][2] === 'IN');
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assert(data[2][3] === 'CNAME');
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assert(
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(data[2][4] === 'a56.d.akamai.net.' && data[1][4] === 'cdn-patch.swtor.com.edgesuite.net.') ||
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(data[2][4] === 'eu.lvlt.cdn.ea.com.c.footprint.net.' && data[1][4] === 'cdn-patch.swtor.com.c.footprint.net.'),
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);
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for (let i = 3, il = data.length; i < il; i++) {
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assert(data[i][0] === data[2][4]);
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assert(data[i][1].match(/^[0-9]{1,3}$/) !== null); //up to 60 seconds if Akamai, at least up to 218 if Level3
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assert(data[i][2] === 'IN');
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assert(data[i][3] === 'A');
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assert(data[i][4].match(/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/) !== null);
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}
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//Prepare return values
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let type: IDnsResult['type'];
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switch (data[1][4]) {
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case 'cdn-patch.swtor.com.edgesuite.net.': type = 'akamai'; break;
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case 'cdn-patch.swtor.com.c.footprint.net.': type = 'level3-eu'; break;
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default: type = 'unknown';
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}
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resolve(data.filter((e, index) => index >= 3).map(([, ttl, , , address]) => ({ ttl: Math.min(Number(ttl), Number(data[0][1]), Number(data[1][1]), Number(data[2][1])), address, type })));
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});
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}
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}) as Promise<IDnsResult[]>;
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}
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//Updates the list of servers based on current DNS data
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async function heartbeatDns(domain: string) {
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//Get list of current patch servers
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const dnsResults = await resolveDns(domain);
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//Remeber time when response came in
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const now = Date.now() - startTime;
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//Schedule next check based on time-to-live, but never longer than 1 minute
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const ttl = Math.min(60, ...(dnsResults.map((obj) => obj.ttl))) + 1;
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setTimeout(heartbeatDns.bind(null, domain), ttl * 1000);
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//Update array with new information
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dnsResults.forEach(
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({ address, type }, index) => {
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//Calculate weight:
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//on cdn-patch.swtor.com: 3 if first, 2 if second, otherwise 1
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let weight = (index < 2) ? (3 - index) : 1;
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//on Level3 US: 1.2 is first, 1 if second
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if (domain !== 'cdn-patch.swtor.com') {
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weight = (index === 0) ? 1.2 : 1;
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}
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//if ip is already contained
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for (let i = 0, il = servers.length; i < il; i++) {
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const server = servers[i];
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if (server.ip === address) {
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server.lastSeen = now;
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server.weight += weight;
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if (server.type !== type) { server.type = type; }
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return;
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}
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}
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//if not yet contained, add to array
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servers.push({
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ip: address,
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lastSeen: now,
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type,
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weight: weight + 1, //give a boost to new values compared to existing values
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});
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},
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);
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//Remove old entries - old = not seen for one hour
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servers = servers.filter((server) => (now - server.lastSeen) < 3600000);
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//Decay weights - reduce them based on update frequency (-50% if full minute, but less if TTL was shorter than a minute)
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const decayFactor = 0.5 ** ((now - lastUpdate) / 60000);
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lastUpdate = now;
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servers.forEach((server) => { server.weight *= decayFactor; });
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//Sort the array by weight
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servers.sort((a, b) => b.weight - a.weight);
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//Output current list
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let output = '';
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servers.forEach((server) => {
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//set colors based on server type, see https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
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//bright color if seen within last 5 minutes
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if (now - server.lastSeen < 300000) { output += '\x1b[1m'; } else { output += '\x1b[0m'; }
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switch (server.type) {
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case 'master': output += '\x1b[37m'; break; //white
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case 'akamai': output += '\x1b[35m'; break; //magenta
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case 'level3-us': output += '\x1b[32m'; break; //green
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case 'level3-eu': output += '\x1b[36m'; break; //cyan
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case 'unknown': default: output += '\x1b[31m'; //red
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}
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output += server.ip;
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output += '\t';
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});
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//Reset color to default
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output += '\x1b[0m';
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console.log(output);
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}
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//start loading additional addresses, both from CDN, and specifically from Level3/North_America so we have more than just European servers
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heartbeatDns('cdn-patch.swtor.com');
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heartbeatDns('na.lvlt.cdn.ea.com.c.footprint.net');
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91
src/cdn/heartbeat.ts
Normal file
91
src/cdn/heartbeat.ts
Normal file
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@ -0,0 +1,91 @@
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import { IServerEntry } from '../interfaces/IDnsResult';
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import resolveDns from './resolveDns';
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/** Time when this script started, for delta time calculations */
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const startTime = Date.now();
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let lastUpdate = 0;
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/** List of servers, sorted by reliability */
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let servers: IServerEntry[] = [];
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//the master source is included by default
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servers.push({ ip: '159.153.92.51', type: 'master', lastSeen: Infinity, weight: Infinity });
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/** Updates the list of servers based on current DNS data */
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async function heartbeatDns(domain: string) {
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//Get list of current patch servers
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const dnsResults = await resolveDns(domain);
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//Remeber time when response came in
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const now = Date.now() - startTime;
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//Schedule next check based on time-to-live, but never longer than 1 minute
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const ttl = Math.min(60, ...(dnsResults.map((obj) => obj.ttl))) + 1;
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setTimeout(heartbeatDns.bind(null, domain), ttl * 1000);
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//Update array with new information
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dnsResults.forEach(
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({ address, type }, index) => {
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//Calculate weight:
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//on cdn-patch.swtor.com: 3 if first, 2 if second, otherwise 1
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let weight = (index < 2) ? (3 - index) : 1;
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//on Level3 US: 1.2 is first, 1 if second
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if (domain !== 'cdn-patch.swtor.com') {
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weight = (index === 0) ? 1.2 : 1;
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}
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//if ip is already contained
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for (let i = 0, il = servers.length; i < il; i += 1) {
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const server = servers[i];
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if (server.ip === address) {
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server.lastSeen = now;
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server.weight += weight;
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if (server.type !== type) { server.type = type; }
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return;
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}
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}
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//if not yet contained, add to array
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servers.push({
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ip: address,
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lastSeen: now,
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type,
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weight: weight + 1, //give a boost to new values compared to existing values
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});
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},
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);
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//Remove old entries - old = not seen for one hour
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servers = servers.filter((server) => (now - server.lastSeen) < 3600000);
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//Decay weights - reduce them based on update frequency (-50% if full minute, but less if TTL was shorter than a minute)
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const decayFactor = 0.5 ** ((now - lastUpdate) / 60000);
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lastUpdate = now;
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servers.forEach((server) => { server.weight *= decayFactor; });
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//Sort the array by weight
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servers.sort((a, b) => b.weight - a.weight);
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//Output current list
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let output = '';
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servers.forEach((server) => {
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//set colors based on server type, see https://en.wikipedia.org/wiki/ANSI_escape_code#Colors
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//bright color if seen within last 5 minutes
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if (now - server.lastSeen < 300000) { output += '\x1b[1m'; } else { output += '\x1b[0m'; }
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switch (server.type) {
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case 'master': output += '\x1b[37m'; break; //white
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case 'akamai': output += '\x1b[35m'; break; //magenta
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case 'level3-us': output += '\x1b[32m'; break; //green
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case 'level3-eu': output += '\x1b[36m'; break; //cyan
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case 'unknown': default: output += '\x1b[31m'; //red
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}
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output += server.ip;
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output += '\t';
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});
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//Reset color to default
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output += '\x1b[0m';
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console.log(output);
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}
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//start loading additional addresses, both from CDN, and specifically from Level3/North_America so we have more than just European servers
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heartbeatDns('cdn-patch.swtor.com');
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heartbeatDns('na.lvlt.cdn.ea.com.c.footprint.net');
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105
src/cdn/resolveDns.ts
Normal file
105
src/cdn/resolveDns.ts
Normal file
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@ -0,0 +1,105 @@
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/* --- DNS resolver for the CDN storing SWTOR's patch files ---
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|
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| The SWTOR launcher first connects to cdn-patch.swtor.com,
|
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| there the traffic is split onto Akamai and Level3, and
|
||||
| distributed to local points of presence.
|
||||
| The master files appear to be stored on 159.153.92.51, and
|
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| all CDNs are synchronized with that source.
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|
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| > cdn-patch.swtor.com
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| -> gslb-patch.swtor.biowareonline.net
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| -> cdn-patch.swtor.com.edgesuite.net (Akamai)
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| | -> a56.d.akamai.net
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| | -> 2.21.74.90
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| | -> 2.21.74.98
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| -> cdn-patch.swtor.com.c.footprint.net (Level3)
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| -> eu.lvlt.cdn.ea.com.c.footprint.net (Europe)
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| | -> 8.12.207.125
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| | -> 8.253.37.126
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| -> na.lvlt.cdn.ea.com.c.footprint.net (US)
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| -> 205.128.74.252
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| -> 4.23.36.253
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| -> 192.221.105.254
|
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|
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| Examples:
|
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| - http://cdn-patch.swtor.com/patch/assets_swtor_main/assets_swtor_main_-1to0.solidpkg
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| - http://159.153.92.51/patch/assets_swtor_main/assets_swtor_main_-1to0.solidpkg
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*/
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import { exec} from 'child_process';
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import * as dns from 'dns';
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import { IDnsResult } from '../interfaces/IDnsResult';
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//TODO: send e-mail with the error
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const assert = (cond: boolean) => { if (!cond) { console.warn('Assert failed'); } };
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/** Looks up the given domain and returns a list of IP addresses, along with their time-to-live */
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async function resolveDns(domain: string): Promise<IDnsResult[]> {
|
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return new Promise((resolve) => {
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//check given string for correctness to prevent injection attacks
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if (!domain.match(/^[a-z0-9]+([-.]{1}[a-z0-9]+)*\.[a-z]{2,3}$/)) { return resolve([]); }
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//Check Level3/North_America separetely
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if (domain !== 'cdn-patch.swtor.com') {
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dns.resolve4(domain, { ttl: true }, (err, result) => {
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return resolve(result.map(({ address, ttl }) => ({ address, ttl, type: 'level3-us' as IDnsResult['type'] })));
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});
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} else {
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//Use bash so we get more information.
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//Also do plenty of asserts to ensure that overall CDN structure has stayed unchanged, and TODO send e-mail if it's different (max. once per hour)
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exec('dig +noall +answer "cdn-patch.swtor.com"', { timeout: 10000 }, (error, stdout) => {
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//check for error
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assert(!error);
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if (error) {
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return resolve([]);
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}
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const data = stdout.trim().split('\n').map((line) => line.split(/\t| /));
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//Verify output
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assert(data.length > 3);
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data.forEach((dataLine) => assert(dataLine.length === 5));
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assert(data[0][0] === 'cdn-patch.swtor.com.');
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assert(data[0][1].match(/^[0-9]{1,3}$/) !== null); //at least up to 598
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assert(data[0][2] === 'IN');
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assert(data[0][3] === 'CNAME');
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assert(data[0][4] === 'gslb-patch.swtor.biowareonline.net.');
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assert(data[1][0] === 'gslb-patch.swtor.biowareonline.net.');
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assert(data[1][1].match(/^[0-9]{1,2}$/) !== null); //up to 60 seconds
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assert(data[1][2] === 'IN');
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assert(data[1][3] === 'CNAME');
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assert(data[1][4] === 'cdn-patch.swtor.com.edgesuite.net.' || data[1][4] === 'cdn-patch.swtor.com.c.footprint.net.');
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assert(data[2][0] === data[1][4]);
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assert(data[2][1].match(/^[0-9]{1,5}$/) !== null); //at least up to 15092 if Akamai, at least up to 627 if Level3
|
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assert(data[2][2] === 'IN');
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assert(data[2][3] === 'CNAME');
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assert(
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(data[2][4] === 'a56.d.akamai.net.' && data[1][4] === 'cdn-patch.swtor.com.edgesuite.net.') ||
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(data[2][4] === 'eu.lvlt.cdn.ea.com.c.footprint.net.' && data[1][4] === 'cdn-patch.swtor.com.c.footprint.net.'),
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);
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for (let i = 3, il = data.length; i < il; i += 1) {
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assert(data[i][0] === data[2][4]);
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||||
assert(data[i][1].match(/^[0-9]{1,3}$/) !== null); //up to 60 seconds if Akamai, at least up to 218 if Level3
|
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assert(data[i][2] === 'IN');
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assert(data[i][3] === 'A');
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assert(data[i][4].match(/^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$/) !== null);
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}
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//Prepare return values
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let type: IDnsResult['type'];
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switch (data[1][4]) {
|
||||
case 'cdn-patch.swtor.com.edgesuite.net.': type = 'akamai'; break;
|
||||
case 'cdn-patch.swtor.com.c.footprint.net.': type = 'level3-eu'; break;
|
||||
default: type = 'unknown';
|
||||
}
|
||||
|
||||
resolve(data.filter((e, index) => index >= 3).map(([, ttl, , , address]) => ({ ttl: Math.min(Number(ttl), Number(data[0][1]), Number(data[1][1]), Number(data[2][1])), address, type })));
|
||||
});
|
||||
}
|
||||
}) as Promise<IDnsResult[]>;
|
||||
}
|
||||
|
||||
export default resolveDns;
|
||||
|
|
@ -16,7 +16,7 @@ interface IServerEntry {
|
|||
ip: string;
|
||||
/** Which network / cloud provider this IP address belongs to. */
|
||||
type: NetworkType;
|
||||
/** When we were last able to resolve to this IP address. */
|
||||
/** When we were last able to resolve to this IP address, time given in milliseconds. */
|
||||
lastSeen: number;
|
||||
/** A measure of how reliable this IP address is, based on how often and how recently it was resolved. */
|
||||
weight: number;
|
||||
|
|
|
|||
Loading…
Reference in a new issue