AGENTS.md

@@ -193,8 +193,9 @@ decision under [The wire](docs/decisions.md#the-wire).
   `message-class.test.ts` and `unsendable.test.ts` is one `SendSmsDeps.send` that answers nothing,
   and a field added to that type fails to compile in every copy at once.
 - `message_id` values the library generates are UUID v7.
-- A test that needs a dummy peer must `resume()` its sockets. An unread socket never processes the
+- A socket a test opens and never reads must be `resume()`d, and a `data` listener counts. An unread
-  peer's FIN, so `server.close()` hangs forever — that is a test bug, not a library one.
+  socket never processes the peer's FIN, so `server.close()` hangs forever — that is a test bug, not
+  a library one.
 - Everything a test opens gets its teardown registered as it is opened, never closed on the test's
   last line: an assertion that throws skips that line, and the listener it leaves behind keeps
   `node --test` alive until CI's ten-minute cap. `test/teardown.ts` covers a session, a server and a
@@ -214,6 +215,8 @@ Each file answers one question, and a fact belongs to the file whose question it
 - **README.md — what you can rely on, and where this is heading.** Observable behaviour, for
   someone using the package, plus the goals and the audience. It carries a reason only where the
   reason changes how you would call the thing.
+- **CHANGELOG.md — what changed for a consumer, per release.** Written for the public, never for the
+  next agent, and a line lands there as the work ships rather than at release.
 - **MIGRATION.md — what a 0.4.0 consumer has to change.** Renamed and removed surface, and the
   behaviour that changed on the wire.
 - **AGENTS.md — what may not change, and why.** Hard rules, architecture, conventions, and an index
@@ -299,6 +302,8 @@ the file.
 - Coming up is not proof a link works, so only one that outlasted `maxDelay` resets the backoff.
 - `reconnect: { fromStart: true }` puts the first connect and bind through that same loop, and
   `client()` then resolves only once it is bound.
+- `connectTimeout` defaults to 10 s, bounds the whole connect including the TLS handshake, and
+  `false` is the one way to turn it off.
 - A stream this library cannot frame is a dead link; one PDU it cannot parse is not.
 - A deliberate shutdown drains; an unusable link and an abort do not.
 - Every segment of a concatenated message is answered as it arrives, so `sendResp()` on one is the

CHANGELOG.md

@@ -0,0 +1,13 @@
+# Changelog
+
+## 0.6.0 (unreleased)
+
+- `client()` now bounds each connect attempt at 10 seconds, the TLS handshake included, and reports
+  one that expires as an ordinary connect failure, so `reconnect` retries it on its usual backoff.
+  A connect previously waited the operating system out, around 130 s on Linux against a host that
+  drops SYNs. `connectTimeout` retunes the bound, and `connectTimeout: false` restores the old wait.
+
+## 0.5.0
+
+The TypeScript rewrite. What a 0.4.0 consumer has to change is in
+[MIGRATION.md](https://gitea.larvit.se/larvit/smpp-js/src/branch/main/MIGRATION.md).

README.md

@@ -227,6 +227,7 @@ All optional. Timeouts and delays are milliseconds.
 | `interfaceVersion` | `0x34` | The SMPP version declared at bind. `0x50` for an SMSC that requires SMPP 5.0. |
 | `systemType`, `addressRange`, `addrTon`, `addrNpi` | `''`, `''`, `0`, `0` | The remaining bind fields, for operators that require them. |
 | `tls` | `false` | `true` for defaults, or a `tls.ConnectionOptions` object for a private CA or a client certificate. |
+| `connectTimeout` | `10000` | Give up on **each connect attempt** the SMSC never completes, the TLS handshake included, and report it as an ordinary connect failure, which `reconnect` then retries. It bounds the socket and the handshake — never the `client()` call, and never the wait for the bind response, which is `responseTimeout`. `false` waits the operating system out instead, around 130 s on Linux; `0` is refused. |
 | `enquireLinkInterval` | `20000` | Interval between `enquire_link` on a quiet link. |
 | `idleTimeout` | `2 × enquireLinkInterval` | Give up on a link the peer has stopped answering, and re-bind unless `reconnect` is `false`. |
 | `responseTimeout` | `30000` | How long to wait for a response, and how long a send with no link waits for the next one. `0` waits forever. |
@@ -629,6 +630,10 @@ if (isCommand(pduObj, 'submit_sm')) {
 | Spec tables | `cmds`, `consts`, `encodings`, `errors`, `tlvs`, `types`, the `cmdsById`, `constsById`, `errorsById` and `tlvsById` maps, and all of them grouped as `defs`. `isCommandName`, `isErrorName`, `isEncodingName`, `commandNameById` and `errorNameById` narrow a value into them. |
 | Types | Every option, result, event payload and table entry has a named type: `ClientOptions`, `ServerOptions`, `SendSmsOptions`, `SendSmsResult`, `Sms`, `Dlr`, `MessageDlr`, `Receipt`, `PduObject`, `PduHeader`, `SmppLog`, `Result` and the rest in `dist/index.d.ts`. |
 
+## What changed per release
+
+See [CHANGELOG.md](https://gitea.larvit.se/larvit/smpp-js/src/branch/main/CHANGELOG.md).
+
 ## Migrating from larvitsmpp 0.4.0
 
 See [MIGRATION.md](https://gitea.larvit.se/larvit/smpp-js/src/branch/main/MIGRATION.md).

docs/decisions.md

@@ -524,6 +524,26 @@ rule and an index of the titles below.
   `LinkGate`'s hold is not — it is awaited with no other handle, so a process whose only work is
   `client()` would exit unbound.
 
+- **`connectTimeout` defaults to 10 s, bounds the whole connect including the TLS handshake, and
+  `false` is the one way to turn it off.** Maintainer's call, 2026-09-20, serving goal 5: a connect
+  that never returns is one `reconnect` cannot retry, because the operating system holds the attempt
+  for around 130 s at Linux's default `tcp_syn_retries` and nothing above it is counting — and no
+  application chooses that, so it is a default rather than an option that switches on what the caller
+  obviously wanted. Accepted: the far end sees roughly four times the SYNs against a dead host, one
+  per ~40 s rather than one per ~160 s, which goal 4 tolerates because the backoff still caps the
+  rate. `false` spells the operating system's wait, as it does for `reconnect`, and `0` is refused
+  naming it, so one spelling reaches each result. What expires is reported as the ordinary connect
+  failure, so the loop retries it like any other, and the message names the peer and whether the TCP
+  connect or the TLS handshake stalled — different faults, different answers. It settles on
+  `secureConnect` for a TLS socket, so a peer that accepts and then says nothing is bounded the same
+  way a black-holed SYN is. Rejected: shipping the option with no default, which left goal 5's "an
+  option does not switch on the thing the caller obviously wanted" unmet, and would have cost a
+  second breaking minor plus a reversal of the `0` spelling to correct later. Rejected:
+  `socket.setTimeout()`, an idle timeout that goes on arming once the link is up. Rejected: bounding
+  it with `responseTimeout`, which names the wait for an answer on a link that already exists and
+  would retune both at once. `server()` shares the checker and ignores the option, as it already
+  ignores `reconnect` — nothing at that end connects out.
+
 - **A stream this library cannot frame is a dead link; one PDU it cannot parse is not.**
   Maintainer's call, 2026-08-31, narrowed 2026-09-05 via the interop plan: a `command_length` below
   16 or above `maxPduLength` leaves nothing that can say where the next PDU starts, so it tears the

src/client.ts

@@ -22,6 +22,7 @@ export type ClientOptions = {
 	addrNpi?: number;
 	addrTon?: number;
 	bindType?: BindType;
+	connectTimeout?: number | false;
 	enquireLinkInterval?: number;
 	host?: string;
 	idleTimeout?: number;
@@ -42,6 +43,7 @@ export type ClientOptions = {
 
 const defaults = {
 	bindType: 'transceiver',
+	connectTimeout: 10_000,
 	enquireLinkInterval: 20_000,
 	host: 'localhost',
 	/** The idle timeout is what notices a dead link, so it has to outlast one silent probe. */
@@ -52,7 +54,30 @@ const defaults = {
 	username: 'user',
 } as const;
 
+function armConnectTimeout(
+	sock: Socket,
+	connectTimeout: number | false,
+	target: { peer: string; secure: boolean },
+	settle: (result: Result<{ sock: Socket }>) => void,
+): NodeJS.Timeout | undefined {
+	if (connectTimeout === false) return undefined;
+
+	let phase = `connecting to ${target.peer}`;
+
+	if (target.secure) {
+		sock.once('connect', () => { phase = `completing the TLS handshake with ${target.peer}`; });
+	}
+
+	return setTimeout(() => {
+		sock.destroy();
+		settle({
+			err: new Error(`Timed out ${phase} after ${String(connectTimeout)} ms; raise connectTimeout or set it to false`),
+		});
+	}, connectTimeout).unref();
+}
+
 function openSocket(options: ClientOptions): Promise<Result<{ sock: Socket }>> {
+	const connectTimeout = options.connectTimeout ?? defaults.connectTimeout;
 	const host = options.host ?? defaults.host;
 	const port = options.port ?? defaults.port;
 	const secure = options.tls !== undefined && options.tls !== false;
@@ -77,11 +102,14 @@ function openSocket(options: ClientOptions): Promise<Result<{ sock: Socket }>> {
 			return;
 		}
 
-		const settle = (result: Result<{ sock: Socket }>): void => {
+		const timer = armConnectTimeout(sock, connectTimeout, { peer: `${host}:${String(port)}`, secure }, settle);
+
+		function settle(result: Result<{ sock: Socket }>): void {
+			clearTimeout(timer);
 			sock.removeListener('error', onError);
 			signal?.removeEventListener('abort', onAbort);
 			resolve(result);
-		};
+		}
 
 		function onError(err: Error): void {
 			settle({ err });

src/error-from.ts

@@ -9,7 +9,9 @@ export function errorFrom(reason: unknown): Error {
 	}
 }
 
-/** String() throws on a null-prototype object or a symbol, so only a string or number is printed. */
+const printable: readonly string[] = ['boolean', 'number', 'string'];
+
+/** String() throws on a null-prototype object, so anything but these is named by its type. */
 export function namedValue(value: unknown): string {
-	return typeof value === 'string' || typeof value === 'number' ? String(value) : typeof value;
+	return printable.includes(typeof value) ? String(value) : typeof value;
 }

src/session-options.ts

@@ -144,14 +144,11 @@ export function checkSessionOptions(options: CheckableOptions): VoidResult {
 		return { err: new Error('fromStart is part of the reconnect policy, spell it reconnect: { fromStart: true }') };
 	}
 
-	const checked = checkLimits([
+	const connect = checkConnectTimeout(options.connectTimeout);
-		['idleTimeout', options.idleTimeout ?? 0, 0],
+
-		['maxOutstanding', options.maxOutstanding ?? defaults.maxOutstanding, 1],
+	if (connect.err) return connect;
-		['maxReassembly', options.maxReassembly ?? defaults.maxReassembly, 1],
+
-		['reassemblyTimeout', options.reassemblyTimeout ?? defaults.reassemblyTimeout, 0],
+	const checked = checkLimits(limitsOf(options));
-		['responseTimeout', options.responseTimeout ?? defaults.responseTimeout, 0],
-		['shutdownTimeout', options.shutdownTimeout ?? defaults.shutdownTimeout, 0],
-	]);
 
 	if (checked.err) return checked;
 
@@ -160,6 +157,35 @@ export function checkSessionOptions(options: CheckableOptions): VoidResult {
 	return backoff.err ? backoff : checkSmsIdFormat(options.smsIdFormat);
 }
 
+function limitsOf(options: CheckableOptions): [string, number, number][] {
+	return [
+		['idleTimeout', options.idleTimeout ?? 0, 0],
+		['maxOutstanding', options.maxOutstanding ?? defaults.maxOutstanding, 1],
+		['maxReassembly', options.maxReassembly ?? defaults.maxReassembly, 1],
+		['reassemblyTimeout', options.reassemblyTimeout ?? defaults.reassemblyTimeout, 0],
+		['responseTimeout', options.responseTimeout ?? defaults.responseTimeout, 0],
+		['shutdownTimeout', options.shutdownTimeout ?? defaults.shutdownTimeout, 0],
+	];
+}
+
+const maxTimerDelay = 2_147_483_647;
+
+function checkConnectTimeout(connectTimeout: unknown): VoidResult {
+	if (connectTimeout === undefined || connectTimeout === false) return {};
+
+	const got = typeof connectTimeout === 'string' ? `"${connectTimeout}"` : namedValue(connectTimeout);
+
+	if (typeof connectTimeout !== 'number' || !Number.isInteger(connectTimeout) || connectTimeout < 1) {
+		return { err: new Error(`connectTimeout must be a whole number of milliseconds, 1 or more, got ${got}; false waits the OS out instead`) };
+	}
+
+	if (connectTimeout > maxTimerDelay) {
+		return { err: new Error(`connectTimeout must be ${String(maxTimerDelay)} ms or less (about 24 days), got ${got}; false waits the OS out instead`) };
+	}
+
+	return {};
+}
+
 function checkLimits(limits: [string, number, number][]): VoidResult {
 	for (const [name, value, min] of limits) {
 		if (!Number.isInteger(value) || value < min) {
@@ -238,6 +264,7 @@ function checkSmsIdFormat(smsIdFormat: unknown): VoidResult {
 
 /** What the checker reads, as it arrives: a caller without types can put anything in it. */
 export type CheckableOptions = {
+	connectTimeout?: unknown;
 	/** Not an option: the one spelling is inside reconnect, and this is where the other is refused. */
 	fromStart?: unknown;
 	idleTimeout?: number | undefined;

test/session-extras.test.ts

@@ -84,6 +84,21 @@ function within<T>(ms: number, promise: Promise<T>): Promise<T | undefined> {
 	return Promise.race([promise, delay(ms).then((): undefined => undefined)]);
 }
 
+/** A client still retrying holds a socket and a timer nothing else releases. */
+function abortAfter(
+	t: TestContext,
+	controller: AbortController,
+	connecting: ReturnType<typeof client>,
+): void {
+	t.after(async () => {
+		controller.abort();
+
+		const { session } = await connecting;
+
+		await session?.close({ signal: AbortSignal.abort() });
+	});
+}
+
 function submitPdu(seqNr: number, cmdStatus: ErrorName = 'ESME_ROK'): PduObject {
 	return {
 		cmdId: 0x00000004,
@@ -798,21 +813,6 @@ describe('reconnect from the first bind', () => {
 		return port;
 	}
 
-	/** A client still retrying holds a socket and a timer nothing else releases. */
-	function abortAfter(
-		t: TestContext,
-		controller: AbortController,
-		connecting: ReturnType<typeof client>,
-	): void {
-		t.after(async () => {
-			controller.abort();
-
-			const { session } = await connecting;
-
-			await session?.close({ signal: AbortSignal.abort() });
-		});
-	}
-
 	test('gives up on the first attempt where reconnect alone is asked for', async () => {
 		const port = await closedPort();
 		const spy = logSpy();
@@ -1018,6 +1018,121 @@ describe('reconnect from the first bind', () => {
 	});
 });
 
+describe('connectTimeout', () => {
+	/** Accepts and then says nothing, so a TLS handshake started on it never completes. */
+	async function stalledListener(t: TestContext): Promise<{ accepted: net.Socket[]; port: number }> {
+		const accepted: net.Socket[] = [];
+		const listener = net.createServer(sock => {
+			accepted.push(sock);
+			sock.resume();
+		});
+
+		closeListenerAfter(t, listener, accepted);
+		await new Promise<void>(resolve => { listener.listen(0, '127.0.0.1', resolve); });
+
+		const address = listener.address();
+
+		return { accepted, port: typeof address === 'object' && address !== null ? address.port : 0 };
+	}
+
+	test('gives up on a connect the peer never completes', async t => {
+		const { port } = await stalledListener(t);
+		const settled = await within(2000, client({
+			connectTimeout: 150,
+			host: '127.0.0.1',
+			port,
+			reconnect: false,
+			tls: true,
+		}));
+
+		assert.ok(settled, 'a handshake nothing answers is what the OS wait would swallow for minutes');
+		assert.ok(settled.err instanceof Error);
+		assert.match(
+			settled.err.message,
+			new RegExp(`Timed out completing the TLS handshake with 127\\.0\\.0\\.1:${String(port)} after 150 ms; raise connectTimeout`),
+			'a firewall and a peer that accepts then stalls need different answers, and whoever reads this has never heard of the option',
+		);
+		assert.equal(settled.session, undefined);
+	});
+
+	// Waits the default out for real: node:test mock timers land in Node 20.4, and the floor is 18.
+	test('bounds a connect nobody asked to bound, at the default ten seconds', async t => {
+		const { port } = await stalledListener(t);
+		const connecting = client({ host: '127.0.0.1', port, reconnect: false, tls: true });
+		const settled = await within(13_000, connecting);
+
+		assert.ok(settled, 'no bound was armed, so nothing ever settled this connect');
+		assert.ok(settled.err instanceof Error);
+		assert.match(settled.err.message, /after 10000 ms/);
+	});
+
+	test('retries a connect it timed out on, like any other failed attempt', async t => {
+		const { accepted, port } = await stalledListener(t);
+		const controller = new AbortController();
+		const connecting = client({
+			connectTimeout: 60,
+			host: '127.0.0.1',
+			port,
+			reconnect: { fromStart: true, maxDelay: 40, minDelay: 10 },
+			signal: controller.signal,
+			tls: true,
+		});
+
+		abortAfter(t, controller, connecting);
+		await delay(400);
+
+		assert.ok(accepted.length >= 3, `the loop retried what timed out, got ${String(accepted.length)} attempts`);
+	});
+
+	test('disarms on the connect that completed, rather than on the socket that follows it', async t => {
+		const smpp = await startServer(t);
+		const { session } = await connect(t, smpp, { connectTimeout: 200 });
+
+		assert.ok(session);
+		await delay(300);
+
+		const probe = await session.send({ cmdName: 'enquire_link' });
+
+		assert.equal(probe.err, undefined);
+		assert.equal(session.sock.destroyed, false);
+	});
+
+	test('refuses a connect timeout that would turn itself off', async () => {
+		assert.match(
+			checkSessionOptions({ connectTimeout: 0 }).err?.message ?? '',
+			/false waits the OS out/,
+			'off is spelled false, so 0 may not stand in for it',
+		);
+		assert.equal(checkSessionOptions({ connectTimeout: false }).err, undefined);
+		assert.match(checkSessionOptions({ connectTimeout: -1 }).err?.message ?? '', /connectTimeout/);
+		assert.match(checkSessionOptions({ connectTimeout: 1.5 }).err?.message ?? '', /whole number/);
+		assert.match(
+			checkSessionOptions({ connectTimeout: '5000' }).err?.message ?? '',
+			/got "5000"/,
+			'an env var read without Number() is the commonest untyped value, and it is a correct number',
+		);
+		assert.match(checkSessionOptions({ connectTimeout: true }).err?.message ?? '', /got true/);
+		assert.match(
+			checkSessionOptions({ connectTimeout: 2_147_483_648 }).err?.message ?? '',
+			/2147483647 ms or less \(about 24 days\), got 2147483648; false waits the OS out instead/,
+			'a delay Node cannot hold in 32 bits fires after 1 ms, the inverse of what it asked for',
+		);
+		assert.equal(checkSessionOptions({ connectTimeout: 2_147_483_647 }).err, undefined);
+		assert.equal(checkSessionOptions({ connectTimeout: 1000 }).err, undefined);
+
+		const refused = await client({ connectTimeout: 0, port: 1 });
+
+		assert.ok(refused.err instanceof Error);
+		assert.match(refused.err.message, /false waits/, 'the socket may not be opened before the option is refused');
+		assert.equal(refused.session, undefined);
+
+		const off = await client({ connectTimeout: false, port: 1 });
+
+		assert.ok(off.err instanceof Error);
+		assert.match(off.err.message, /ECONNREFUSED/, 'false opts out of the bound without breaking the connect');
+	});
+});
+
 describe('sends across a reconnect', () => {
 	/** Answers every message after the first, which is left to hold the send window open. */
 	function answerAfterTheFirst(smpp: SmppServer, arrived: string[]): Latch {

test/session.test.ts

@@ -1493,7 +1493,6 @@ describe('robustness', () => {
 	// 0.4.0 registered a listener per sequence number and waited forever, leaking one per call.
 	test('gives up on a peer that never answers', async t => {
 		const accepted: net.Socket[] = [];
-		// resume() so the socket drains; an unread socket never notices the peer hanging up.
 		const silent = net.createServer(sock => { accepted.push(sock); sock.resume(); });
 
 		await new Promise<void>(resolve => silent.listen(0, resolve));

todo.md

@@ -179,16 +179,22 @@ the rewrite, for a dependency added later. Maintainer's call, 2026-09-14.
 
 ## Worth doing, not blocking
 
-- [ ] **Give up a connect after `connectTimeout` instead of waiting the OS out.** `openSocket()` in
+- [ ] **Cut the three teardown sentences `test/teardown.ts` already says.** Under AGENTS.md's
-      `client.ts` settles only on `connect`/`secureConnect`, a socket `error`, or the caller's
+      Conventions, "`test/teardown.ts` covers a session, a server and a listener" restates its two
-      `signal`, and `reconnect-loop.ts` times nothing but its backoff — so a host that drops SYNs
+      exported names, "Its close aborts rather than drains" restates `closeAfter`'s own doc comment,
-      stalls every attempt for the OS TCP timeout, around 130 s on Linux at the default
+      and the `net.Server.close()` sentence restates `closeListenerAfter`'s. Keep the registered-at-
-      `tcp_syn_retries`, and `reconnect.fromStart` cannot retry what never returns. The option aborts
+      creation rule and the FIFO one, which nothing else states, and drop "CI's ten-minute cap" —
-      the socket and returns the ordinary connect failure; absent, the wait stays exactly 0.5.0's, so
+      that number lives in `.gitea/workflows/test.yaml`. Raised by the prose pass, 2026-09-20.
-      a call passing no options is unchanged (goal 6). Whether a later major makes it a default is
+
-      the open half. Found comparing 0.5.0 with the seven `larvitsmpp` forks, 2026-09-20 —
+- [ ] **Refuse a delay Node's timers cannot hold, in `checkLimits`.** `idleTimeout`,
-      [SwiftHero/larvitsmpp](https://github.com/SwiftHero/larvitsmpp) added a 10 s connect timeout in
+      `reassemblyTimeout`, `responseTimeout` and `shutdownTimeout` take any integer, and `setTimeout`
-      2017, and it is the one fork change with no equivalent here.
+      fires after 1 ms for anything above 2147483647 — so a value in the wrong unit gets the inverse
+      of what it asked for, explained only by a warning on stderr. `connectTimeout` refuses one
+      already, which is the asymmetry to close. The same four print an untyped value bare, so
+      `idleTimeout: '5000'` is refused with `got 5000` — a value the reader reads as correct — where
+      `connectTimeout` quotes it. `namedValue()`'s four sites — `messagingMode`, `encoding`, the time
+      options and `smsIdFormat` — are the same defect once more: there `true` and `'true'` both print
+      as `true`. One fix closes all three. Raised by review, 2026-09-20.
 
 - [ ] **A send the codec will refuse waits for a link and a window slot first.** `refuse()` in
       `outgoing-requests.ts` runs `misuse()` and the abort check before the wait, precisely so a call