Address the CodeRabbit review: inbound SMS, binary payloads and untrusted input

.github/workflows/release.yaml

@@ -13,6 +13,8 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
+        with:
+          persist-credentials: false
       - uses: actions/setup-node@v5
         with:
           cache: npm

.github/workflows/test.yaml

@@ -5,11 +5,16 @@ on:
     branches: ['**']
   pull_request:
 
+permissions:
+  contents: read
+
 jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@v5
+        with:
+          persist-credentials: false
       - uses: actions/setup-node@v5
         with:
           cache: npm
@@ -27,6 +32,8 @@ jobs:
         node: ['18', '20', '22', '24']
     steps:
       - uses: actions/checkout@v5
+        with:
+          persist-credentials: false
       - uses: actions/setup-node@v5
         with:
           cache: npm

AGENTS.md

@@ -43,6 +43,7 @@ src/
 	dlr.ts               Delivery receipts: text and TLV parsing, receipt status codes
 	dlr-merger.ts        DlrMerger: per-segment receipts counted into one MessageDlr
 	expiring-groups.ts   ExpiringGroups: the capped, expiring store both of those share
+	incoming-requests.ts Every request the peer sends: messages, receipts, links, unknown commands
 	link-timers.ts       LinkTimers: the enquire_link heartbeat and the idle timeout
 	log.ts               silentLog — the default when the application passes none
 	message.ts           Encoding detection, splitting, bit counting, SMPP date formatting
@@ -118,6 +119,8 @@ implementation (see todo.md).
 | Unrangechecked writes | Integer params are handed to `writeUInt8`/`writeUInt16BE` unvalidated, so an out-of-range value throws from inside Node |
 | `submit_multi` missing `sm_length` | The field is commented out of the command table, so `short_message` never round-trips for that command |
 | Per-parameter defaults never applied | `calcCmdLength` reads `paramType.default` (the wire type's) rather than the parameter's, so `interface_version: 0x50` on the bind commands did nothing and every bind declared version 0x00 |
+| `source_telematics_id` width | Defined as a 2-octet integer; SMPP 3.4 5.3.2.8 makes it 1 octet, unlike `dest_telematics_id`, which really is 2 |
+| Binary payloads decoded as text | `data_coding` 0x02, 0x04, 0x14 and 0xF4-0xF7 are 8-bit binary and land on the GSM 03.38 table, which rewrites every octet outside it. They resolve to LATIN1 now, so the payload survives as bytes |
 | `ESME_RINVBCASTCHANIND` typo | Defined as `0x011`, three hex digits; the spec value is `0x0112` |
 
 ## Multipart sends and the send window
@@ -170,10 +173,12 @@ exactly 140.
   because silently stripping a caller's explicit TLVs off a deliberately public low-level surface
   would be worse than sending them. The guarantee is "what this library sends honours the rule",
   never "the session cannot send optional parameters to an old peer".
-- **Only the server feeds `peerInterfaceVersion`.** `acceptBind()` records what the peer declared;
-  the client never reads `sc_interface_version` out of its bind response, so a client session is
-  permissive. That is not a defect today — this library's ESME direction sends no TLVs at all — but
-  anyone adding a client-side TLV owes the other half of the feed.
+- **Both ends feed `peerInterfaceVersion`, and a peer that declared nothing is pre-3.4.**
+  `acceptBind()` records what the ESME declared in its bind request; the client's `bind()` records
+  the `sc_interface_version` the SMSC answered with. A peer that declared no version is recorded as
+  `undeclaredInterfaceVersion` (0x00) and is sent no optional parameters — the spec reads an absent
+  `sc_interface_version` as an SMSC that supports none. `undefined` is left to mean one thing only:
+  no bind has been accepted on this session yet.
 - **The library speaks SMPP 3.4 on the wire, and `defs/` keeps the 5.0 tables as a superset.**
   Maintainer's call, 2026-08-26: 3.4 is what SMSCs actually run, while the wider tables let the codec
   parse and build whatever a peer sends. The declared version is an option on both `client()` and

README.md

@@ -116,6 +116,21 @@ to reconcile against a later receipt, not enough to resend the rest, so treat a
 failed message. A message needing more than 255 segments is refused before anything is sent, since
 the concatenation header numbers segments in a single octet.
 
+### Receiving
+
+A `receiver` or `transceiver` client gets mobile-originated messages as `sms` events — the same
+handle the server side gets, answered the same way:
+
+```javascript
+session.on('sms', async sms => {
+	// sms.from, sms.to, sms.message
+	await sms.sendResp();
+});
+```
+
+Delivery receipts travel on the same SMPP command but reach you as `dlr`, so nothing you write has
+to tell the two apart.
+
 ## Server
 
 The simplest possible server — no authentication, listening on port 2775:
@@ -168,6 +183,9 @@ await smpp.close();      // stop listening and close every live session
 `sendDlr` accepts `SCHEDULED`, `ENROUTE`, `DELIVERED`, `EXPIRED`, `DELETED`, `UNDELIVERABLE`,
 `ACCEPTED`, `UNKNOWN`, `REJECTED` and `SKIPPED`.
 
+A message whose `data_coding` says 8-bit binary arrives as Latin-1, so `Buffer.from(sms.message,
+'latin1')` gives you back the original octets.
+
 ### Server options
 
 | Option | Default | |
@@ -229,7 +247,7 @@ const { err, pduObj } = await session.send({
 
 `acceptsOptionalParams()` answers whether the peer declared SMPP 3.4 or later, which is the version
 at and above which the spec allows optional parameters to be sent to it; `peerInterfaceVersion` is
-the raw value it declared. The library's own senders consult the first before attaching a TLV — a
+the version it declared, `0x00` if it declared none. The library's own senders consult the first before attaching a TLV — a
 `send()` you build yourself is passed through as written, so consult it too when you attach TLVs.
 
 ## Working with PDUs directly

src/client.ts

@@ -3,7 +3,7 @@ import type { LogInt } from '@larvit/log';
 import type { Result, VoidResult } from './result.ts';
 import type { Socket } from 'node:net';
 import { Session } from './session.ts';
-import { checkSessionOptions } from './session-options.ts';
+import { checkSessionOptions, undeclaredInterfaceVersion } from './session-options.ts';
 import { connect as netConnect } from 'node:net';
 import { connect as tlsConnect } from 'node:tls';
 import { defaultInterfaceVersion } from './defs/constants.ts';
@@ -107,11 +107,10 @@ function bindParams(options: ClientOptions, systemId: string) {
 async function bind(session: Session, options: ClientOptions): Promise<VoidResult> {
 	const bindType = options.bindType ?? defaults.bindType;
 	const systemId = options.username ?? defaults.username;
-	const sent = await session.send({
-		cmdName: `bind_${bindType}`,
-		params: bindParams(options, systemId),
-		...(options.signal ? { signal: options.signal } : {}),
-	});
+	const sent = await session.send(
+		{ cmdName: `bind_${bindType}`, params: bindParams(options, systemId) },
+		options.signal ? { signal: options.signal } : {},
+	);
 
 	if (sent.err) return { err: sent.err };
 
@@ -124,7 +123,12 @@ async function bind(session: Session, options: ClientOptions): Promise<VoidResul
 		return { err: new Error(`Remote host refused login: ${sent.pduObj.cmdStatus ?? 'unknown'}`) };
 	}
 
+	const declared = sent.pduObj.tlvs.sc_interface_version?.tagValue;
+
 	session.loggedIn = true;
+	session.peerInterfaceVersion = typeof declared === 'number'
+		? declared
+		: undeclaredInterfaceVersion;
 	session.log.info('client - bound', { bindType, systemId });
 
 	return {};

src/defs/encodings.ts

@@ -87,7 +87,10 @@ const latin1: Encoding = {
 
 const ucs2: Encoding = {
 	decode(buffer) {
-		return Buffer.from(buffer).swap16().toString('utf16le');
+		// A peer-controlled sm_length can cut a character in half, and swap16() refuses odd lengths.
+		const whole = buffer.length - (buffer.length % 2);
+
+		return Buffer.from(buffer.subarray(0, whole)).swap16().toString('utf16le');
 	},
 
 	encode(value) {
@@ -113,22 +116,35 @@ export function detect(value: string): EncodingName {
 	return 'UCS2';
 }
 
-/**
- * SMPP data_coding is a flat table for 0x00-0x0E, but the 0x1X and 0xFX ranges carry a GSM message
- * class and encode the alphabet in bits 3-2 (or bit 2) instead — which is how a flash UCS2 message
- * arrives as 0x18. Alphabets with no codec here fall back to ASCII.
- */
-export function encodingByDataCoding(dataCoding: number): EncodingName {
+/** The 0x1X and 0xFX ranges carry a GSM message class and put the alphabet in bits 3-2 or bit 2. */
+function messageClassEncoding(dataCoding: number): EncodingName | undefined {
 	if ((dataCoding & 0xF0) === 0x10) {
-		return ((dataCoding >> 2) & 0x03) === 0x02 ? 'UCS2' : 'ASCII';
+		const alphabet = (dataCoding >> 2) & 0x03;
+
+		if (alphabet === 0x01) return 'LATIN1';
+
+		return alphabet === 0x02 ? 'UCS2' : 'ASCII';
 	}
 
 	if ((dataCoding & 0xF0) === 0xF0) {
-		return 'ASCII';
+		return (dataCoding & 0x04) === 0x04 ? 'LATIN1' : 'ASCII';
 	}
 
-	if (dataCoding === 0x03) return 'LATIN1';
+	return undefined;
+}
+
+/**
+ * SMPP data_coding is a flat table for 0x00-0x0E, and the message class ranges are how a flash UCS2
+ * message arrives as 0x18. The 8-bit binary codings resolve to LATIN1, the one codec here that maps
+ * every octet to a code point and back unchanged, so a binary payload survives; alphabets with no
+ * codec fall back to ASCII.
+ */
+export function encodingByDataCoding(dataCoding: number): EncodingName {
+	const messageClass = messageClassEncoding(dataCoding);
+
+	if (messageClass) return messageClass;
 	if (dataCoding === 0x08) return 'UCS2';
 
-	return 'ASCII';
+	// 0x02 and 0x04 are 8-bit binary, 0x03 is Latin-1.
+	return dataCoding >= 0x02 && dataCoding <= 0x04 ? 'LATIN1' : 'ASCII';
 }

src/defs/tlvs.ts

@@ -22,7 +22,7 @@ const specs = tlvSpecs({
 	source_addr_subunit: { id: 0x000D, tag: 'source_addr_subunit', type: tlv.int8 },
 	source_network_type: { id: 0x000E, tag: 'source_network_type', type: tlv.int8 },
 	source_bearer_type: { id: 0x000F, tag: 'source_bearer_type', type: tlv.int8 },
-	source_telematics_id: { id: 0x0010, tag: 'source_telematics_id', type: tlv.int16 },
+	source_telematics_id: { id: 0x0010, tag: 'source_telematics_id', type: tlv.int8 },
 	qos_time_to_live: { id: 0x0017, tag: 'qos_time_to_live', type: tlv.int32 },
 	payload_type: { id: 0x0019, tag: 'payload_type', type: tlv.int8 },
 	additional_status_info_text: { id: 0x001D, tag: 'additional_status_info_text', type: tlv.cstring },

src/defs/types.ts

@@ -142,6 +142,15 @@ function wantUnsuccessSmes(value: ParamValue): Result<{ smes: UnsuccessSme[] }>
 }
 
 function readCstring(buffer: Buffer, offset: number): Result<{ bytesRead: number; value: string }> {
+	// An offset at the end exactly is an absent trailing field, which real peers do send.
+	if (outOfRange(buffer, offset, 0)) {
+		return {
+			err: new Error(
+				`C-Octet String starts at offset ${String(offset)}, past a ${String(buffer.length)} octet buffer`,
+			),
+		};
+	}
+
 	let length = 0;
 
 	while (buffer[offset + length]) {
@@ -197,6 +206,29 @@ export const int8 = intType(1, 0xFF, (b, o) => b.readUInt8(o), (b, v, o) => b.wr
 export const int16 = intType(2, 0xFFFF, (b, o) => b.readUInt16BE(o), (b, v, o) => b.writeUInt16BE(v, o));
 export const int32 = intType(4, 0xFFFFFFFF, (b, o) => b.readUInt32BE(o), (b, v, o) => b.writeUInt32BE(v, o));
 
+const intByOctets: Record<number, WireType<number>> = { 1: int8, 2: int16, 4: int32 };
+
+/**
+ * The TLV header's length is what the parser skips past, so it is also the width the value is read
+ * at — a peer that types a tag one octet wider than the table says still gets the value it meant.
+ */
+function tlvInt(declared: WireType<number>): WireType<number> {
+	return {
+		...declared,
+		read(buffer, offset, length) {
+			if (length === undefined) return declared.read(buffer, offset);
+
+			const width = intByOctets[length];
+
+			if (!width) {
+				return { err: new Error(`Integer TLV declares ${String(length)} octets, expected 1, 2 or 4`) };
+			}
+
+			return width.read(buffer, offset);
+		},
+	};
+}
+
 /** Octet String: a length octet followed by that many octets. */
 export const string: WireType<string> = {
 	default: '',
@@ -513,9 +545,9 @@ export const tlv = {
 			return err ? { err } : writeCstring(text, buf, offset);
 		},
 	} satisfies WireType<string>,
-	int8,
-	int16,
-	int32,
+	int8: tlvInt(int8),
+	int16: tlvInt(int16),
+	int32: tlvInt(int32),
 	string: {
 		default: '',
 		read(buf: Buffer, offset: number, length = 0) {

src/dlr.ts

@@ -82,8 +82,7 @@ function receiptDate(value: string | undefined): Date | undefined {
 
 	const [, years, months, days, hours, minutes, seconds] = match;
 	const century = Math.floor(new Date().getUTCFullYear() / 100) * 100;
-
-	return new Date(Date.UTC(
+	const date = new Date(Date.UTC(
 		century + Number(years),
 		Number(months) - 1,
 		Number(days),
@@ -91,6 +90,15 @@ function receiptDate(value: string | undefined): Date | undefined {
 		Number(minutes),
 		Number(seconds ?? 0),
 	));
+
+	// Date.UTC rolls 31 February over into March rather than refusing it.
+	const rolled = date.getUTCMonth() !== Number(months) - 1
+		|| date.getUTCDate() !== Number(days)
+		|| date.getUTCHours() !== Number(hours)
+		|| date.getUTCMinutes() !== Number(minutes)
+		|| date.getUTCSeconds() !== Number(seconds ?? 0);
+
+	return rolled ? undefined : date;
 }
 
 /**

src/incoming-requests.ts

@@ -0,0 +1,137 @@
+import type { DlrMerger } from './dlr-merger.ts';
+import type { LogInt } from '@larvit/log';
+import type { OnRequest } from './session-options.ts';
+import type { PduObject } from './pdu.ts';
+import type { Session } from './session.ts';
+import { Reassembler, decodeSegments } from './reassembly.ts';
+import { bindCommands, defaults } from './session-options.ts';
+import { concatInfo } from './udh.ts';
+import { consts } from './defs/constants.ts';
+import { createSms } from './sms.ts';
+import { dlrFromPdu } from './dlr.ts';
+import { paramText } from './defs/types.ts';
+
+export type IncomingRequestsOptions = {
+	dlrMerger: DlrMerger;
+	log: LogInt;
+	maxOctets?: number | undefined;
+	maxReassembly?: number | undefined;
+	onRequest?: OnRequest | undefined;
+	reassemblyTimeout?: number | undefined;
+	session: Session;
+	systemId?: string | undefined;
+};
+
+/** Everything the peer asks of a session: messages, receipts, links and the answers to them. */
+export class IncomingRequests {
+	private readonly dlrMerger: DlrMerger;
+	private readonly log: LogInt;
+	private readonly onRequest: OnRequest | undefined;
+	private readonly reassembler: Reassembler;
+	private readonly session: Session;
+	private readonly systemId: string;
+
+	constructor(options: IncomingRequestsOptions) {
+		this.dlrMerger = options.dlrMerger;
+		this.log = options.log;
+		this.onRequest = options.onRequest;
+		this.reassembler = new Reassembler({
+			log: options.log,
+			max: options.maxReassembly ?? defaults.maxReassembly,
+			maxOctets: options.maxOctets,
+			timeout: options.reassemblyTimeout ?? defaults.reassemblyTimeout,
+		});
+		this.session = options.session;
+		this.systemId = options.systemId ?? defaults.systemId;
+	}
+
+	async handle(pduObj: PduObject): Promise<void> {
+		if (this.onRequest && await this.onRequest(this.session, pduObj)) return;
+
+		switch (pduObj.cmdName) {
+			case 'deliver_sm':
+				await this.onDeliverSm(pduObj);
+				break;
+			case 'enquire_link':
+				await this.session.sendReturn(pduObj);
+				break;
+			case 'submit_sm':
+				this.onMessage(pduObj);
+				break;
+			case 'unbind':
+				await this.session.sendReturn(pduObj);
+				this.session.close();
+				break;
+			default:
+				await this.unhandled(pduObj);
+		}
+	}
+
+	/** Drops the segments of every message that never became whole. */
+	clear(): void {
+		this.reassembler.clear();
+	}
+
+	private async unhandled(pduObj: PduObject): Promise<void> {
+		if (bindCommands.includes(pduObj.cmdName)) {
+			this.log.info('session - bind on an already bound session', { cmdName: pduObj.cmdName });
+			await this.session.sendReturn(pduObj, 'ESME_RALYBND', { system_id: this.systemId });
+
+			return;
+		}
+
+		this.log.info('session - no handler for command', { cmdName: pduObj.cmdName });
+		await this.session.sendReturn(pduObj, 'ESME_RINVCMDID');
+	}
+
+	/** SMPP carries a mobile-originated message and a delivery receipt on the same command. */
+	private async onDeliverSm(pduObj: PduObject): Promise<void> {
+		const dlr = dlrFromPdu(pduObj);
+
+		if (!dlr) {
+			this.onMessage(pduObj);
+
+			return;
+		}
+
+		this.session.emit('dlr', dlr, pduObj);
+
+		const merged = this.dlrMerger.collect(dlr);
+
+		if (merged) this.session.emit('messageDlr', merged);
+
+		await this.session.sendReturn(pduObj);
+	}
+
+	private onMessage(pduObj: PduObject): void {
+		const message = pduObj.params.short_message;
+		const esmClass = pduObj.params.esm_class;
+		const hasUdh = typeof esmClass === 'number'
+			&& (esmClass & consts.ESM_CLASS.UDH_INDICATOR) === consts.ESM_CLASS.UDH_INDICATOR;
+		const concat = hasUdh && Buffer.isBuffer(message) ? concatInfo(message) : undefined;
+
+		if (!concat) {
+			this.emitSms([pduObj]);
+
+			return;
+		}
+
+		const whole = this.reassembler.collect(pduObj, concat);
+
+		if (whole) this.emitSms(whole);
+	}
+
+	private emitSms(pduObjs: PduObject[]): void {
+		const first = pduObjs[0];
+
+		if (!first) return;
+
+		this.session.emit('sms', createSms({
+			from: paramText(first.params.source_addr),
+			message: decodeSegments(pduObjs),
+			pduObjs,
+			session: this.session,
+			to: paramText(first.params.destination_addr),
+		}));
+	}
+}

src/reassembly.ts

@@ -122,6 +122,15 @@ export class Reassembler {
 	collect(pduObj: PduObject, concat: ConcatInfo): PduObject[] | undefined {
 		this.sweep();
 
+		if (concat.part < 1 || concat.total < 1 || concat.part > concat.total) {
+			this.log.warn('reassembler - dropping a segment the UDH numbers impossibly', {
+				part: concat.part,
+				total: concat.total,
+			});
+
+			return undefined;
+		}
+
 		const key = groupKey(pduObj, concat.reference);
 		const group = this.groups.get(key) ?? this.open(key, concat.total);
 		const replaced = group.parts.get(concat.part);

src/reconnect-loop.ts

@@ -90,7 +90,7 @@ export class ReconnectLoop {
 			return false;
 		}
 
-		const up = await this.options.onConnected(opened.sock);
+		const up = await this.bringUp(opened.sock);
 
 		if (up.err) {
 			this.options.log.warn('reconnect - could not come back up', { message: up.err.message });
@@ -102,4 +102,19 @@ export class ReconnectLoop {
 
 		return false;
 	}
+
+	/** The loop owns the socket until the owner is up on it, so a failed handover must not leak it. */
+	private async bringUp(sock: Socket): Promise<VoidResult> {
+		try {
+			const up = await this.options.onConnected(sock);
+
+			if (up.err) sock.destroy();
+
+			return up;
+		} catch (thrown: unknown) {
+			sock.destroy();
+
+			return { err: thrown instanceof Error ? thrown : new Error(String(thrown)) };
+		}
+	}
 }

src/server.ts

@@ -5,7 +5,7 @@ import type { Server as NetServer, Socket } from 'node:net';
 import type { Server as TlsServer, TlsOptions } from 'node:tls';
 import { EventEmitter } from 'node:events';
 import { Session, bindCommands, defaultSystemId } from './session.ts';
-import { checkSessionOptions } from './session-options.ts';
+import { checkSessionOptions, undeclaredInterfaceVersion } from './session-options.ts';
 import { createServer as createNetServer } from 'node:net';
 import { createServer as createTlsServer } from 'node:tls';
 import { defaultInterfaceVersion } from './defs/constants.ts';
@@ -148,7 +148,9 @@ async function acceptBind(
 	const declared = pduObj.params.interface_version;
 
 	session.loggedIn = true;
-	session.peerInterfaceVersion = typeof declared === 'number' ? declared : undefined;
+	session.peerInterfaceVersion = typeof declared === 'number'
+		? declared
+		: undeclaredInterfaceVersion;
 
 	await session.sendReturn(pduObj, 'ESME_ROK', identity, bindRespTlvs(session, options));
 }

src/session-options.ts

@@ -27,6 +27,13 @@ export const bindCommands: readonly string[] = [
 
 export type SendOptions = { signal?: AbortSignal | undefined };
 
+/**
+ * First refusal on every incoming request. Returning true means the hook answered it and the
+ * built-in handling is skipped — this is how the server owns bind without the session also
+ * replying "invalid command".
+ */
+export type OnRequest = (session: Session, pduObj: PduObject) => Promise<boolean>;
+
 /**
  * How to come back after an unexpected disconnect. The session owns the retry loop; the caller
  * supplies how to open a socket and what to do once it is open (bind, for a client).
@@ -45,12 +52,7 @@ export type SessionOptions = {
 	maxOctets?: number | undefined;
 	maxOutstanding?: number | undefined;
 	maxReassembly?: number | undefined;
-	/**
-	 * First refusal on every incoming request. Returning true means the hook answered it and the
-	 * built-in handling is skipped — this is how the server owns bind without the session also
-	 * replying "invalid command".
-	 */
-	onRequest?: ((session: Session, pduObj: PduObject) => Promise<boolean>) | undefined;
+	onRequest?: OnRequest | undefined;
 	reassemblyTimeout?: number | undefined;
 	reconnect?: ReconnectOptions | undefined;
 	responseTimeout?: number | undefined;
@@ -61,6 +63,9 @@ export type SessionOptions = {
 
 export const defaultSystemId = '';
 
+/** SMPP 3.4: a peer that declares no version at all is one from before optional parameters. */
+export const undeclaredInterfaceVersion = 0x00;
+
 export const defaults = {
 	/** Receipts of a multipart message can be a working day apart, so the cap does the bounding. */
 	dlrMergeTimeout: 86_400_000,

src/session.ts

@@ -9,19 +9,15 @@ import type { SendSmsOptions, SendSmsResult } from './send-sms.ts';
 import type { Socket } from 'node:net';
 import { DlrMerger } from './dlr-merger.ts';
 import { EventEmitter } from 'node:events';
+import { IncomingRequests } from './incoming-requests.ts';
 import { LinkTimers } from './link-timers.ts';
 import { PduFramer } from './pdu-framer.ts';
 import { PendingRequests } from './pending-requests.ts';
 import { ReconnectLoop } from './reconnect-loop.ts';
-import { Reassembler, decodeSegments } from './reassembly.ts';
 import { SendWindow } from './send-window.ts';
-import { concatInfo } from './udh.ts';
-import { consts, optionalParamsMinVersion } from './defs/constants.ts';
-import { createSms } from './sms.ts';
+import { optionalParamsMinVersion } from './defs/constants.ts';
 import { bindCommands, defaultSystemId, defaults } from './session-options.ts';
-import { dlrFromPdu } from './dlr.ts';
 import { isResp, objToPdu, pduReturn, pduToObj } from './pdu.ts';
-import { paramText } from './defs/types.ts';
 import { silentLog } from './log.ts';
 import { submitSms } from './send-sms.ts';
 
@@ -42,14 +38,14 @@ export class Session extends EventEmitter<SessionEvents> {
 	readonly log: LogInt;
 
 	loggedIn = false;
-	/** The interface_version the peer declared when binding; undefined until a bind is accepted. */
+	/** What the peer declared when binding: 0x00 if it declared none, undefined before any bind. */
 	peerInterfaceVersion: number | undefined = undefined;
 	userData: unknown = undefined;
 
 	private readonly dlrMerger: DlrMerger;
+	private readonly incoming: IncomingRequests;
 	private readonly options: SessionOptions;
 	private readonly pending: PendingRequests;
-	private readonly reassembler: Reassembler;
 	private readonly reconnectLoop: ReconnectLoop | undefined;
 	private readonly timers: LinkTimers;
 	private readonly window: SendWindow;
@@ -87,13 +83,17 @@ export class Session extends EventEmitter<SessionEvents> {
 			max: defaults.maxDlrMerges,
 			timeout: defaults.dlrMergeTimeout,
 		});
-		this.pending = new PendingRequests(this.log);
-		this.reassembler = new Reassembler({
+		this.incoming = new IncomingRequests({
+			dlrMerger: this.dlrMerger,
 			log: this.log,
-			max: options.maxReassembly ?? defaults.maxReassembly,
 			maxOctets: options.maxOctets,
-			timeout: options.reassemblyTimeout ?? defaults.reassemblyTimeout,
+			maxReassembly: options.maxReassembly,
+			onRequest: options.onRequest,
+			reassemblyTimeout: options.reassemblyTimeout,
+			session: this,
+			systemId: options.systemId,
 		});
+		this.pending = new PendingRequests(this.log);
 		this.reconnectLoop = this.loopFor(options.reconnect);
 		this.sock = options.sock;
 		this.timers = new LinkTimers({
@@ -243,6 +243,11 @@ export class Session extends EventEmitter<SessionEvents> {
 		input: PduObjectInput,
 		options: SendOptions,
 	): Promise<Result<{ pduObj: PduObject }>> {
+		// pending.wait() alone settles the caller while the request still goes out to the peer.
+		if (options.signal?.aborted === true) {
+			return { err: new Error('Aborted before the request was sent') };
+		}
+
 		const seqNr = this.pending.nextSeqNr();
 		const built = objToPdu({ ...input, seqNr });
 
@@ -270,7 +275,7 @@ export class Session extends EventEmitter<SessionEvents> {
 		this.timers.clear();
 		this.pending.settleAll(new Error('Session closed before a response arrived'));
 		this.dlrMerger.clear();
-		this.reassembler.clear();
+		this.incoming.clear();
 		this.sock.destroy();
 		this.emit('close');
 	}
@@ -343,7 +348,7 @@ export class Session extends EventEmitter<SessionEvents> {
 
 		this.emit('incomingPduObj', pduObj);
 		// Every application hook and listener reached from an incoming PDU funnels through here.
-		void this.handle(pduObj).catch((thrown: unknown) => {
+		void this.incoming.handle(pduObj).catch((thrown: unknown) => {
 			const err = thrown instanceof Error ? thrown : new Error(String(thrown));
 
 			this.log.error('session - a handler threw', { message: err.message });
@@ -351,95 +356,6 @@ export class Session extends EventEmitter<SessionEvents> {
 		});
 	}
 
-	private async handle(pduObj: PduObject): Promise<void> {
-		const onRequest = this.options.onRequest;
-
-		if (onRequest && await onRequest(this, pduObj)) return;
-
-		switch (pduObj.cmdName) {
-			case 'deliver_sm':
-				await this.onDeliverSm(pduObj);
-				break;
-			case 'enquire_link':
-				await this.sendReturn(pduObj);
-				break;
-			case 'submit_sm':
-				this.onSubmitSm(pduObj);
-				break;
-			case 'unbind':
-				await this.sendReturn(pduObj);
-				this.close();
-				break;
-			default:
-				await this.unhandled(pduObj);
-		}
-	}
-
-	private async unhandled(pduObj: PduObject): Promise<void> {
-		if (bindCommands.includes(pduObj.cmdName)) {
-			this.log.info('session - bind on an already bound session', { cmdName: pduObj.cmdName });
-			await this.sendReturn(pduObj, 'ESME_RALYBND', {
-				system_id: this.options.systemId ?? defaults.systemId,
-			});
-
-			return;
-		}
-
-		this.log.info('session - no handler for command', { cmdName: pduObj.cmdName });
-		await this.sendReturn(pduObj, 'ESME_RINVCMDID');
-	}
-
-	private onSubmitSm(pduObj: PduObject): void {
-		const message = pduObj.params.short_message;
-		const esmClass = pduObj.params.esm_class;
-		const hasUdh = typeof esmClass === 'number'
-			&& (esmClass & consts.ESM_CLASS.UDH_INDICATOR) === consts.ESM_CLASS.UDH_INDICATOR;
-		const concat = hasUdh && Buffer.isBuffer(message) ? concatInfo(message) : undefined;
-
-		if (!concat) {
-			this.emitSms([pduObj]);
-
-			return;
-		}
-
-		const whole = this.reassembler.collect(pduObj, concat);
-
-		if (whole) this.emitSms(whole);
-	}
-
-	private emitSms(pduObjs: PduObject[]): void {
-		const first = pduObjs[0];
-
-		if (!first) return;
-
-		this.emit('sms', createSms({
-			from: paramText(first.params.source_addr),
-			message: decodeSegments(pduObjs),
-			pduObjs,
-			session: this,
-			to: paramText(first.params.destination_addr),
-		}));
-	}
-
-	private async onDeliverSm(pduObj: PduObject): Promise<void> {
-		const dlr = dlrFromPdu(pduObj);
-
-		if (!dlr) {
-			this.log.info('session - deliver_sm carries no delivery report', { seqNr: pduObj.seqNr });
-			await this.sendReturn(pduObj, 'ESME_RINVTLVSTREAM');
-
-			return;
-		}
-
-		this.emit('dlr', dlr, pduObj);
-
-		const merged = this.dlrMerger.collect(dlr);
-
-		if (merged) this.emit('messageDlr', merged);
-
-		await this.sendReturn(pduObj);
-	}
-
 	private resetTimers(): void {
 		if (this.closed) return;
 

test/dlr.test.ts

@@ -104,6 +104,14 @@ describe('dlrFromPdu()', () => {
 		}
 	});
 
+	test('leaves an impossible receipt date undefined rather than rolling it over', () => {
+		const rolled = dlrFromPdu(deliverSm('id:x stat:DELIVRD done date:9902310000'));
+
+		assert.ok(rolled);
+		assert.equal(rolled.doneDate, undefined);
+		assert.equal(dlrFromPdu(deliverSm('id:x stat:DELIVRD done date:2501012560'))?.doneDate, undefined);
+	});
+
 	test('returns nothing when the PDU identifies no message', () => {
 		assert.equal(dlrFromPdu(deliverSm('just a normal sms')), undefined);
 	});

test/encodings.test.ts

@@ -50,6 +50,12 @@ describe('LATIN1', () => {
 			assert.equal(encodings.LATIN1.decode(Buffer.from(bytes)), str);
 		}
 	});
+
+	test('carries every octet through unchanged, which is what makes it the binary codec', () => {
+		const every = Buffer.from(Array.from({ length: 256 }, (_, byte) => byte));
+
+		assert.deepEqual(encodings.LATIN1.encode(encodings.LATIN1.decode(every)), every);
+	});
 });
 
 describe('UCS2', () => {
@@ -78,6 +84,15 @@ describe('UCS2', () => {
 
 		assert.deepEqual(buffer, Buffer.from([0x00, 0x20]));
 	});
+
+	// swap16() throws ERR_INVALID_BUFFER_SIZE on an odd octet count, and sm_length is peer-controlled.
+	test('drops an incomplete trailing octet instead of throwing', () => {
+		const odd = Buffer.from([0x00, 0x41, 0x00, 0x42, 0x00]);
+
+		assert.equal(encodings.UCS2.decode(odd), 'AB');
+		assert.equal(encodings.UCS2.decode(Buffer.from([0x41])), '');
+		assert.deepEqual(odd, Buffer.from([0x00, 0x41, 0x00, 0x42, 0x00]));
+	});
 });
 
 describe('detect()', () => {
@@ -111,6 +126,12 @@ describe('encodingByDataCoding()', () => {
 		assert.equal(encodingByDataCoding(0xF0), 'ASCII');
 	});
 
+	test('resolves the 8-bit binary codings to the codec that keeps every octet', () => {
+		for (const dataCoding of [0x02, 0x04, 0x14, 0xF4, 0xF7]) {
+			assert.equal(encodingByDataCoding(dataCoding), 'LATIN1');
+		}
+	});
+
 	test('falls back to ASCII for alphabets it has no codec for', () => {
 		assert.equal(encodingByDataCoding(0x05), 'ASCII');
 		assert.equal(encodingByDataCoding(0x0E), 'ASCII');

test/interop.test.ts

@@ -204,7 +204,7 @@ describe('the reference encoder against our parser', () => {
 });
 
 describe('a live session against the reference implementation', () => {
-	test('our client binds to a reference server and delivers an SMS', async () => {
+	test('our client binds to a reference server and delivers an SMS', async t => {
 		const received: { from: string; message: string }[] = [];
 		const refServer = reference.createServer({}, (session: ReferenceSession) => {
 			session.on('bind_transceiver', pdu => {
@@ -226,11 +226,14 @@ describe('a live session against the reference implementation', () => {
 			});
 		});
 
+		t.after(() => new Promise<void>(resolve => { refServer.close(() => { resolve(); }); }));
 		await new Promise<void>(resolve => { refServer.listen(0, () => { resolve(); }); });
 
 		const port = refServer.address()?.port ?? 0;
 		const { err, session } = await client({ port });
 
+		t.after(() => { session?.close(); });
+
 		assert.equal(err, undefined);
 		assert.ok(session);
 
@@ -243,14 +246,13 @@ describe('a live session against the reference implementation', () => {
 		assert.equal(sent.err, undefined);
 		assert.deepEqual(sent.smsIds, ['ref-id']);
 		assert.deepEqual(received, [{ from: 'MyBrand', message: 'interop check' }]);
-
-		session.close();
-		await new Promise<void>(resolve => { refServer.close(() => { resolve(); }); });
 	});
 
-	test('a reference client binds to our server and delivers an SMS', async () => {
+	test('a reference client binds to our server and delivers an SMS', async t => {
 		const { err: serverErr, server: smpp } = await server({ port: 0 });
 
+		t.after(async () => { await smpp?.close(); });
+
 		assert.equal(serverErr, undefined);
 		assert.ok(smpp);
 
@@ -262,6 +264,8 @@ describe('a live session against the reference implementation', () => {
 			url: `smpp://localhost:${String(smpp.port)}`,
 		});
 
+		t.after(() => { refSession.close(); });
+
 		await new Promise<void>(resolve => {
 			refSession.bind_transceiver({ password: 'bar', system_id: 'foo' }, () => { resolve(); });
 		});
@@ -277,8 +281,5 @@ describe('a live session against the reference implementation', () => {
 		assert.equal(sms.from, '46701113311');
 		assert.equal(sms.message, 'from the reference client');
 		await sms.sendResp();
-
-		refSession.close();
-		await smpp.close();
 	});
 });

test/message.test.ts

@@ -110,6 +110,16 @@ describe('encodeMessage() and decodeMessage()', () => {
 		assert.equal(decodeMessage(buffer, 0x08).message, 'hej 一');
 	});
 
+	test('keeps a binary payload octet for octet instead of running it through GSM 03.38', () => {
+		const payload = Buffer.from([0x00, 0x1B, 0x60, 0x80, 0xFF]);
+
+		assert.deepEqual(Buffer.from(decodeMessage(payload, 0x04).message, 'latin1'), payload);
+	});
+
+	test('decodes the whole characters of a UCS2 payload cut in half by sm_length', () => {
+		assert.equal(decodeMessage(Buffer.from([0x00, 0x68, 0x00, 0x65, 0x00]), 0x08).message, 'he');
+	});
+
 	test('strips a UDH when the esm_class says one is present', () => {
 		const withUdh = Buffer.concat([
 			Buffer.from([0x05, 0x00, 0x03, 0x01, 0x02, 0x01]),

test/session-extras.test.ts

@@ -28,8 +28,18 @@ async function startServer(options: Parameters<typeof server>[0] = {}): Promise<
 	return smpp;
 }
 
+/** An event that never fires would otherwise block until the CI job limit, asserting nothing. */
 function once<T>(register: (resolve: (value: T) => void) => void): Promise<T> {
-	return new Promise<T>(resolve => { register(resolve); });
+	return new Promise<T>((resolve, reject) => {
+		const timer = setTimeout(() => {
+			reject(new Error('waited 5000 ms for an event that never fired'));
+		}, 5000);
+
+		register(value => {
+			clearTimeout(timer);
+			resolve(value);
+		});
+	});
 }
 
 describe('merged delivery reports', () => {
@@ -345,6 +355,16 @@ describe('reassembly bounds', () => {
 		assert.equal(reassembler.size, 0);
 	});
 
+	// The UDH is peer-controlled, and the default authenticate() accepts every peer.
+	test('refuses a segment whose concatenation metadata cannot be honoured', () => {
+		const reassembler = new Reassembler({ log: silentLog, max: 10, now: () => 0, timeout: 60_000 });
+
+		assert.equal(collect(reassembler, 1, 1, 0), undefined);
+		assert.equal(collect(reassembler, 2, 0, 3), undefined);
+		assert.equal(collect(reassembler, 3, 4, 3), undefined);
+		assert.equal(reassembler.size, 0);
+	});
+
 	// 0.4.0 held incomplete groups without limit and swept them only when other traffic arrived.
 	test('drops the oldest incomplete message once the cap is reached', () => {
 		const reassembler = new Reassembler({ log: silentLog, max: 2, now: () => 0, timeout: 60_000 });

test/session.test.ts

@@ -5,15 +5,19 @@ import type { Dlr } from '../src/dlr.ts';
 import type { PduObject, PduObjectInput } from '../src/pdu.ts';
 import type { Sms } from '../src/sms.ts';
 import type { SmppServer } from '../src/server.ts';
+import type { TestContext } from 'node:test';
+import type { VoidResult } from '../src/result.ts';
 import { DlrMerger } from '../src/dlr-merger.ts';
 import { PduFramer } from '../src/pdu-framer.ts';
 import { ReconnectLoop } from '../src/reconnect-loop.ts';
 import { Session, bindCommands } from '../src/session.ts';
 import { client } from '../src/client.ts';
+import { consts } from '../src/defs/constants.ts';
 import { isCommand, objToPdu, pduReturn, pduToObj } from '../src/pdu.ts';
 import { paramText } from '../src/defs/types.ts';
 import { server } from '../src/server.ts';
 import { silentLog } from '../src/log.ts';
+import { splitMessage } from '../src/message.ts';
 
 async function startServer(options: Parameters<typeof server>[0] = {}): Promise<SmppServer> {
 	const { err, server: smpp } = await server({ ...options, port: 0 });
@@ -391,6 +395,33 @@ describe('bind', () => {
 		peer.close();
 		await smpp.close();
 	});
+
+	test('records the version the SMSC declared in its bind response', async t => {
+		const smpp = await startServer({ interfaceVersion: 0x50 });
+
+		t.after(() => smpp.close());
+
+		const { session } = await connect(smpp);
+
+		assert.ok(session);
+		t.after(() => { session.close(); });
+		assert.equal(session.peerInterfaceVersion, 0x50);
+		assert.ok(session.acceptsOptionalParams());
+	});
+
+	// The spec: an absent sc_interface_version means the SMSC supports no optional parameters.
+	test('takes an SMSC that declares no version as older than 3.4', async t => {
+		const peer = await bindOnlyPeer();
+
+		t.after(() => peer.close());
+
+		const { session } = await client({ port: peer.port });
+
+		assert.ok(session);
+		t.after(() => { session.close(); });
+		assert.equal(session.peerInterfaceVersion, 0x00);
+		assert.equal(session.acceptsOptionalParams(), false);
+	});
 });
 
 describe('sending', () => {
@@ -517,6 +548,84 @@ describe('sending', () => {
 	});
 });
 
+describe('receiving', () => {
+	async function inbound(t: TestContext): Promise<{ peer: Session; session: Session }> {
+		const smpp = await startServer();
+
+		t.after(() => smpp.close());
+
+		const bound = once<Session>(resolve => { smpp.on('session', resolve); });
+		const { session } = await connect(smpp);
+
+		assert.ok(session);
+		t.after(() => { session.close(); });
+
+		return { peer: await bound, session };
+	}
+
+	test('hands a client a deliver_sm that is not a delivery receipt', async t => {
+		const { peer, session } = await inbound(t);
+		const incoming = once<Sms>(resolve => { session.on('sms', resolve); });
+		const delivered = peer.send({
+			cmdName: 'deliver_sm',
+			params: {
+				destination_addr: '46709771337',
+				short_message: 'inbound hello',
+				source_addr: '46701113311',
+			},
+		});
+		const sms = await raceWithin(2000, incoming);
+
+		assert.ok(sms, 'a deliver_sm that carries no receipt is an inbound SMS');
+		assert.equal(sms.from, '46701113311');
+		assert.equal(sms.to, '46709771337');
+		assert.equal(sms.message, 'inbound hello');
+
+		await sms.sendResp({ smsId: 'inbound-id' });
+
+		const answered = await delivered;
+
+		assert.ok(answered.pduObj);
+		assert.equal(answered.pduObj.cmdName, 'deliver_sm_resp');
+		assert.equal(answered.pduObj.params.message_id, 'inbound-id');
+	});
+
+	test('reassembles a multipart inbound SMS before the sms event', async t => {
+		const message = 'Inbound lorem ipsum dolor sit amet consectetur, '.repeat(6);
+		const { peer, session } = await inbound(t);
+		const incoming = once<Sms>(resolve => { session.on('sms', resolve); });
+		const segments = splitMessage(message, { reference: 42 });
+
+		assert.equal(segments.length, 2);
+
+		const delivered = Promise.all(segments.map(segment => peer.send({
+			cmdName: 'deliver_sm',
+			params: {
+				destination_addr: '46709771337',
+				esm_class: consts.ESM_CLASS.UDH_INDICATOR,
+				short_message: segment,
+				source_addr: '46701113311',
+			},
+		})));
+		const sms = await raceWithin(2000, incoming);
+
+		assert.ok(sms, 'both segments should reassemble into one message');
+		assert.equal(sms.message, message);
+		assert.equal(sms.pduObjs.length, 2);
+
+		await sms.sendResp({ smsId: 'inbound-long' });
+
+		const ids: string[] = [];
+
+		for (const answered of await delivered) {
+			assert.ok(answered.pduObj);
+			ids.push(paramText(answered.pduObj.params.message_id));
+		}
+
+		assert.deepEqual(ids, ['inbound-long-1', 'inbound-long-2']);
+	});
+});
+
 describe('delivery reports', () => {
 	test('reaches the sender as a dlr event', async () => {
 		const smpp = await startServer();
@@ -860,6 +969,75 @@ describe('robustness', () => {
 		assert.ok(await closed);
 		await smpp.close();
 	});
+
+	// An aborted send that still reaches the SMSC bills a message the caller believes never went out.
+	test('puts nothing on the wire for a signal that is already aborted', async t => {
+		const smpp = await startServer();
+
+		t.after(() => smpp.close());
+
+		const bound = once<Session>(resolve => { smpp.on('session', resolve); });
+		const { session } = await connect(smpp);
+
+		assert.ok(session);
+		t.after(() => { session.close(); });
+
+		const peer = await bound;
+		const controller = new AbortController();
+		const seen: string[] = [];
+
+		peer.on('incomingPduObj', pduObj => { seen.push(pduObj.cmdName); });
+		controller.abort();
+
+		const sent = await session.sendSms({
+			from: '46701113311',
+			message: 'must never reach the peer',
+			to: '46709771337',
+		}, { signal: controller.signal });
+
+		assert.ok(sent.err instanceof Error);
+		await delay(50);
+		assert.deepEqual(seen, []);
+	});
+
+	// A socket the loop opened and never handed over is one leaked per retry, forever.
+	test('leaves no socket open when coming back up fails', async () => {
+		const opened: net.Socket[] = [];
+
+		function onConnected(): Promise<VoidResult> {
+			if (opened.length === 1) return Promise.resolve({ err: new Error('bind refused') });
+
+			throw new Error('bind exploded');
+		}
+
+		const loop = new ReconnectLoop({
+			connect: () => {
+				const sock = new net.Socket();
+
+				opened.push(sock);
+
+				return Promise.resolve({ sock });
+			},
+			log: silentLog,
+			maxDelay: 10,
+			minDelay: 1,
+			onConnected,
+		});
+
+		loop.schedule();
+
+		const destroyed = await waitFor(() => opened.length >= 2
+			&& opened[0]?.destroyed === true
+			&& opened[1]?.destroyed === true);
+
+		loop.stop();
+
+		for (const sock of opened) {
+			sock.destroy();
+		}
+
+		assert.ok(destroyed, 'a failed setup should leave no socket open');
+	});
 });
 
 describe('application hooks that throw', () => {

test/types.test.ts

@@ -1,6 +1,7 @@
 import assert from 'node:assert/strict';
 import test, { describe } from 'node:test';
 import type { DestAddress, UnsuccessSme } from '../src/defs/types.ts';
+import { tlvs } from '../src/defs/tlvs.ts';
 import { types } from '../src/defs/types.ts';
 
 describe('integers', () => {
@@ -102,6 +103,42 @@ describe('cstring (C-Octet String)', () => {
 	test('refuses a string with no terminator rather than running off the end', () => {
 		assert.ok(types.cstring.read(Buffer.from('abcd'), 0).err instanceof Error);
 	});
+
+	test('refuses one that starts past the end instead of inventing an empty value', () => {
+		assert.ok(types.cstring.read(encoded, encoded.length + 1).err instanceof Error);
+		assert.ok(types.cstring.read(encoded, -1).err instanceof Error);
+
+		// At the end exactly the field is absent, not corrupt: peers truncate a NULL-only body.
+		assert.deepEqual(types.cstring.read(encoded, encoded.length), { bytesRead: 1, value: '' });
+	});
+});
+
+describe('integer TLVs', () => {
+	const encoded = Buffer.from([0x00, 0x00, 0x01, 0x02]);
+
+	// The TLV header's length is what the parser skips, so it is what the value must be read at.
+	test('read the width the TLV header declares', () => {
+		assert.deepEqual(types.tlv.int8.read(encoded, 0, 4), { bytesRead: 4, value: 0x00000102 });
+		assert.deepEqual(types.tlv.int16.read(encoded, 2, 2), { bytesRead: 2, value: 0x0102 });
+		assert.deepEqual(types.tlv.int32.read(encoded, 3, 1), { bytesRead: 1, value: 0x02 });
+		assert.deepEqual(types.tlv.int16.read(encoded, 2), { bytesRead: 2, value: 0x0102 });
+	});
+
+	test('refuse a length no integer field can have', () => {
+		assert.ok(types.tlv.int8.read(encoded, 0, 0).err instanceof Error);
+		assert.ok(types.tlv.int16.read(encoded, 0, 3).err instanceof Error);
+		assert.ok(types.tlv.int32.read(encoded, 0, 8).err instanceof Error);
+	});
+
+	test('stay bounds-checked at the declared width', () => {
+		assert.ok(types.tlv.int8.read(Buffer.alloc(2), 0, 4).err instanceof Error);
+	});
+
+	// SMPP 3.4 5.3.2.7-8: the two telematics ids are deliberately different widths.
+	test('are the width the spec gives each tag', () => {
+		assert.equal(tlvs.source_telematics_id.type, types.tlv.int8);
+		assert.equal(tlvs.dest_telematics_id.type, types.tlv.int16);
+	});
 });
 
 describe('buffer', () => {

todo.md

@@ -5,7 +5,7 @@ rules there constrain every item below.
 
 ## Status
 
-The rewrite is **feature complete and green**: 190 tests, lint and typecheck clean, verified on Node
+The rewrite is **feature complete and green**: 208 tests, lint and typecheck clean, verified on Node
 18, 20, 22 and 24. What is left is release work and a few things worth adding before or after 1.0.0.
 
 ```bash
@@ -22,10 +22,10 @@ public surface is documented in [README.md](README.md); this is the short form.
 import { client, server } from '@larvit/smpp';
 
 const { err, session } = await client({ host, password, port, username });
-const { err, pduObjs, smsIds } = await session.sendSms({ dlr, from, message, to });
+const { err: sendErr, pduObjs, smsIds } = await session.sendSms({ dlr, from, message, to });
 await session.unbind();
 
-const { err, server: smpp } = await server({ authenticate, port });
+const { err: serverErr, server: smpp } = await server({ authenticate, port });
 smpp.on('session', session => {
 	session.on('sms', async sms => {
 		await sms.sendResp();