signal-desktop/ts/util/dns.ts
2023-12-12 23:57:09 +01:00

132 lines
3.3 KiB
TypeScript

// Copyright 2023 Signal Messenger, LLC
// SPDX-License-Identifier: AGPL-3.0-only
import type {
LookupOneOptions,
LookupAllOptions,
LookupAddress,
lookup as nodeLookup,
} from 'dns';
import { ipcRenderer, net } from 'electron';
import type { ResolvedHost } from 'electron';
import { strictAssert } from './assert';
import { drop } from './drop';
function lookupAll(
hostname: string,
opts: LookupOneOptions | LookupAllOptions,
callback: (
err: NodeJS.ErrnoException | null,
addresses: string | Array<LookupAddress>,
family?: number
) => void
): void {
// Node.js support various signatures, but we only support one.
strictAssert(typeof opts === 'object', 'missing options');
strictAssert(typeof callback === 'function', 'missing callback');
async function run() {
let result: ResolvedHost;
try {
let queryType: 'A' | 'AAAA' | undefined;
if (opts.family === 4) {
queryType = 'A';
} else if (opts.family === 6) {
queryType = 'AAAA';
}
if (net) {
// Main process
result = await net.resolveHost(hostname, {
queryType,
});
} else {
// Renderer
result = await ipcRenderer.invoke(
'net.resolveHost',
hostname,
queryType
);
}
const addresses = result.endpoints.map(({ address, family }) => {
let numericFamily = -1;
if (family === 'ipv4') {
numericFamily = 4;
} else if (family === 'ipv6') {
numericFamily = 6;
}
return {
address,
family: numericFamily,
};
});
if (!opts.all) {
const random = addresses.at(
Math.floor(Math.random() * addresses.length)
);
if (random === undefined) {
callback(
new Error(`Hostname: ${hostname} cannot be resolved`),
'',
-1
);
return;
}
callback(null, random.address, random.family);
return;
}
callback(null, addresses);
} catch (error) {
callback(error, []);
}
}
drop(run());
}
export function interleaveAddresses(
addresses: ReadonlyArray<LookupAddress>
): Array<LookupAddress> {
const firstAddr = addresses.find(
({ family }) => family === 4 || family === 6
);
if (!firstAddr) {
throw new Error('interleaveAddresses: no addresses to interleave');
}
const v4 = addresses.filter(({ family }) => family === 4);
const v6 = addresses.filter(({ family }) => family === 6);
// Interleave addresses for Happy Eyeballs, but keep the first address
// type from the DNS response first in the list.
const interleaved = new Array<LookupAddress>();
while (v4.length !== 0 || v6.length !== 0) {
const v4Entry = v4.pop();
const v6Entry = v6.pop();
if (firstAddr.family === 4) {
if (v4Entry !== undefined) {
interleaved.push(v4Entry);
}
if (v6Entry !== undefined) {
interleaved.push(v6Entry);
}
} else {
if (v6Entry !== undefined) {
interleaved.push(v6Entry);
}
if (v4Entry !== undefined) {
interleaved.push(v4Entry);
}
}
}
return interleaved;
}
// Note: `nodeLookup` has a complicated type due to compatibility requirements.
export const electronLookup = lookupAll as typeof nodeLookup;