feat(core): TCP timing and closing after Java, measured with Java FILIUS

TCP follows Java's TCPSocket where it differs from Swift: each attempt and
TIME_WAIT wait three round trips that follow the speed (8250 ms at 90 %),
counted from when the segment is handed down, before ARP; the next segment
ends TIME_WAIT; the other end closes by itself on FIN; data no one
acknowledges closes with FIN; the accepted socket has the listener's
initial sequence number, and the listener takes the next.

Not taken from Java: three SYNs, not one (Java's retry loop ends after
the first timeout), named in tcpJava.test.ts as JAVA_BUGS.

tcpJava.test.ts compares TcpRun's three stories frame by frame and state
by state; the Swift comparison only checks that the TCP scenarios differ.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
This commit is contained in:
2026-09-30 11:17:44 +00:00
co-authored by Claude Opus 5.5
parent cd3c6a432c
commit cec0a92f95
8 changed files with 488 additions and 129 deletions
+16 -105
View File
@@ -1,133 +1,44 @@
// DHCP as Java FILIUS runs it. tools/java-oracle's DhcpRun built each
// scenario's network in Java FILIUS, ran it and wrote what every network card
// saw (<name>.java.json, FILIUS' own packet log). The engine runs the same
// network. For each DHCP client, the frames that concern it must come in the
// same order, with the same content, at about the same distance from each
// other, and every host must end with the same addresses.
// saw (<name>.java.json). The engine runs the same network. For each DHCP
// client, the frames that concern it must come in the same order, with the
// same content, at about the same distance from each other (javaRun.ts), and
// every host must end with the same addresses.
//
// A frame counts when it first shows on any card (sent, or received), in
// Java and in the engine alike. Not only on the client's own card: there,
// FILIUS' log misses the DISCOVER of the client that sends second when two
// start together (measured in four of four runs of dhcp-lan; the server
// receives it) — a fault of the log, not of the network. Java logs no frame
// identity; the same text within DUPLICATE_WINDOW_MILLISECONDS is one frame
// (measured: a frame reaches the last card within some 130 ms; the closest
// two distinct frames of the same text are the DISCOVERs around a DECLINE,
// some 520 ms apart).
//
// Java runs on threads in real time, at the default speed of 90 % (55 ms a
// cable, a round trip time of 2750 ms). Its gaps match the engine's within a
// few milliseconds, except where a card sends two frames at once: Java's
// cable carries one frame at a time (SimplexVerbindung sleeps the delay with
// the port's buffer locked, and the sender waits), the engine's cable all of
// them together — up to three cables' delay, measured. A gap may differ by
// GAP_TOLERANCE_MILLISECONDS; a wrong round trip time (250 ms) may not. Java draws the link-local
// address with Math.random; it is compared as 169.254.1.x. Where several
// clients start together, which one is first varies in Java (the first
// thread pays for loading the classes); a client is therefore compared
// without the other clients' frames and the answers to them.
// Java draws the link-local address with Math.random; it is compared as
// 169.254.1.x. Where several clients start together, which one is first
// varies in Java (the first thread pays for loading the classes); a client is
// therefore compared without the other clients' frames and the answers to
// them.
import { readdirSync, readFileSync } from 'node:fs';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';
import { describe, expect, it } from 'vitest';
import { NetworkRuntimeEngine, stableMacAddress, type EthernetFrame } from '../src/index.js';
import { snapshotOf, type Scenario } from './scenario.js';
import { stableMacAddress } from '../src/index.js';
import { GAP_TOLERANCE_MILLISECONDS, javaFrames, watchedEngine, type JavaFrame, type SeenFrame } from './javaRun.js';
import { type Scenario } from './scenario.js';
const scenarioDirectory = join(dirname(fileURLToPath(import.meta.url)), 'scenarios');
const GAP_TOLERANCE_MILLISECONDS = 200;
const DUPLICATE_WINDOW_MILLISECONDS = 300;
interface JavaFrame {
time: number;
source: string;
destination: string;
arp?: number;
senderIp?: string;
targetIp?: string;
sourceIp?: string;
destinationIp?: string;
protocol?: number;
sourcePort?: number;
destinationPort?: number;
payload?: string;
icmp?: number;
}
interface JavaRun {
frames: Record<string, JavaFrame[]>;
devices: Record<string, [string, string, string, string]>;
}
interface SeenFrame {
readonly time: number;
readonly text: string;
}
const LINK_LOCAL = /169\.254\.1\.\d+/g;
function javaText(frame: JavaFrame): string {
const macs = `${frame.source} > ${frame.destination}`.toUpperCase();
if (frame.arp !== undefined) return `${macs} ARP ${frame.arp === 1 ? 'request' : 'reply'} ${frame.senderIp} > ${frame.targetIp}`;
if (frame.icmp !== undefined) return `${macs} ICMP ${frame.icmp}`;
return `${macs} UDP ${frame.sourceIp}:${frame.sourcePort} > ${frame.destinationIp}:${frame.destinationPort} ${frame.payload}`;
}
function engineText(frame: EthernetFrame): string {
const macs = `${frame.sourceMacAddress} > ${frame.destinationMacAddress}`.toUpperCase();
if (frame.payload.kind === 'arp') {
const arp = frame.payload.packet;
return `${macs} ARP ${arp.operation} ${arp.senderIPAddress} > ${arp.targetIPAddress}`;
}
const packet = frame.payload.packet;
if (packet.payload.kind !== 'udp') return `${macs} ${packet.payload.kind.toUpperCase()}`;
const datagram = packet.payload.datagram;
return `${macs} UDP ${packet.senderIPAddress}:${datagram.sourcePort} > ${packet.receiverIPAddress}:${datagram.destinationPort} ${new TextDecoder().decode(datagram.payload)}`;
}
/** The engine's run of the scenario's network, without its steps, for `milliseconds`. */
function runEngine(scenario: Scenario, milliseconds: number) {
const engine = new NetworkRuntimeEngine(scenario.seed);
const framesByIdentity = new Map<number, EthernetFrame>();
const send = engine.sendEthernetFrame.bind(engine);
engine.sendEthernetFrame = (fromNodeId, outgoingPortId, frame) => {
framesByIdentity.set(frame.identity, frame);
send(fromNodeId, outgoingPortId, frame);
};
engine.handle({ type: 'start', snapshot: snapshotOf(scenario), seed: scenario.seed, initialTimeMilliseconds: 0 });
const { engine, frames } = watchedEngine(scenario);
engine.handle({ type: 'advance', toMilliseconds: milliseconds });
// Every frame when it first shows on a host's card (as FILIUS logs it: sent, or received).
const hosts = new Set(scenario.nodes.filter((node) => node.kind !== 'networkSwitch').map((node) => node.id));
const firstSeen = new Map<number, SeenFrame>();
for (const event of engine.state.packetTraces) {
if (event.layer !== 'physical' || !hosts.has(event.nodeId) || event.frameIdentity === undefined) continue;
if (!((event.direction === 'outbound' && event.operation === 'sent') || (event.direction === 'inbound' && event.operation === 'received'))) continue;
if (firstSeen.has(event.frameIdentity)) continue;
firstSeen.set(event.frameIdentity, { time: event.timeMilliseconds, text: engineText(framesByIdentity.get(event.frameIdentity)!) });
}
const devices = Object.fromEntries(
[...engine.state.topologySnapshot.deviceConfigurations].map(([node, device]) => [
node,
[device.ipAddress, device.subnetMask, device.defaultGateway, device.dnsServer],
]),
);
return { frames: [...firstSeen.values()], devices };
}
/** Java's frames of all cards, each once: the same text within the window is the same frame. */
function javaFrames(java: JavaRun): SeenFrame[] {
const all = Object.values(java.frames)
.flat()
.map((frame) => ({ time: frame.time, text: javaText(frame) }))
.sort((lhs, rhs) => lhs.time - rhs.time);
const frames: SeenFrame[] = [];
for (const frame of all) {
if (frames.some((each) => each.text === frame.text && frame.time - each.time <= DUPLICATE_WINDOW_MILLISECONDS)) continue;
frames.push(frame);
}
return frames;
return { frames: frames(), devices };
}
/** Consecutive frames without the other clients' own: the text, and the time since the one before. */
@@ -147,7 +58,7 @@ function clientMac(scenario: Scenario, nodeId: string): string {
}
const runs = readdirSync(scenarioDirectory)
.filter((name) => name.endsWith('.java.json'))
.filter((name) => name.startsWith('dhcp-') && name.endsWith('.java.json'))
.map((name) => name.replace('.java.json', ''))
.sort();
@@ -166,7 +77,7 @@ describe('DHCP as Java FILIUS runs it', () => {
const clients = scenario.dhcpClients ?? [];
for (const client of clients) {
const others = clients.filter((each) => each !== client).map((each) => clientMac(scenario, each));
const expected = steps(javaFrames(java), others);
const expected = steps(javaFrames(java.frames), others);
const actual = steps(engine.frames, others);
for (let index = 0; index < Math.max(expected.length, actual.length); index += 1) {
expect(actual[index]?.text, `${client} frame #${index + 1}`).toBe(expected[index]?.text);