feat: foreign device registration

examples/discover-devices-via-bbmd.ts

@@ -0,0 +1,52 @@
+/**
+ * Discover devices through BBMD:
+ * 1) Register as foreign device
+ * 2) Send Who-Is using BVLC Distribute-Broadcast-To-Network (0x09)
+ *
+ * Usage:
+ *   npx ts-node examples/discover-devices-via-bbmd.ts <bbmd-ip:port> [ttl-seconds]
+ */
+
+import Bacnet from '../src'
+
+const bbmdAddress = process.argv[2]
+const ttlSeconds = Number(process.argv[3] || 60)
+const localPort = Number(process.env.BACNET_PORT || 47809)
+
+if (!bbmdAddress) {
+	console.error('Missing BBMD address. Usage: <bbmd-ip:port> [ttl-seconds]')
+	process.exit(1)
+}
+
+const client = new Bacnet({
+	apduTimeout: 5000,
+	interface: '0.0.0.0',
+	port: localPort,
+})
+
+client.on('error', (err: Error) => {
+	console.error(`BACnet error: ${err.message}`)
+})
+
+client.on('iAm', (device: any) => {
+	console.log(
+		`iAm from ${device?.payload?.deviceId} via ${device?.header?.sender?.address} (forwardedFrom=${device?.header?.sender?.forwardedFrom ?? 'n/a'})`,
+	)
+})
+
+client.on('listening', async () => {
+	try {
+		console.log(`Listening on UDP ${localPort}`)
+		await client.registerForeignDevice({ address: bbmdAddress }, ttlSeconds)
+		console.log(`FDR success on ${bbmdAddress} (ttl=${ttlSeconds}s)`)
+		client.whoIsThroughBBMD({ address: bbmdAddress })
+		console.log('Who-Is sent through BBMD')
+	} catch (err) {
+		console.error(`Failed: ${String((err as Error)?.message || err)}`)
+	}
+})
+
+setTimeout(() => {
+	client.close()
+	console.log('Done')
+}, 20000)

examples/register-foreign-device.ts

@@ -0,0 +1,111 @@
+/**
+ * Register this BACnet client as a Foreign Device in a BBMD and periodically renew it.
+ *
+ * Usage:
+ *   npx ts-node examples/register-foreign-device.ts <bbmd-ip:port> [ttl-seconds]
+ *
+ * Example:
+ *   npx ts-node examples/register-foreign-device.ts 192.168.40.10:47808 900
+ */
+
+import Bacnet from '../src'
+
+const bbmdAddress = process.argv[2] || process.env.BBMD_ADDRESS
+const ttlSeconds = Number(process.argv[3] || process.env.FDR_TTL || 900)
+const localPort = Number(process.env.BACNET_PORT || 47809)
+const renewRatio = Number(process.env.FDR_RENEW_RATIO || 0.8)
+
+if (!bbmdAddress) {
+	console.error(
+		'Missing BBMD address. Pass <bbmd-ip:port> or set BBMD_ADDRESS.',
+	)
+	process.exit(1)
+}
+
+if (!Number.isInteger(ttlSeconds) || ttlSeconds <= 0 || ttlSeconds > 0xffff) {
+	console.error('Invalid TTL. Expected integer in range 1..65535.')
+	process.exit(1)
+}
+
+const renewDelayMs = Math.max(
+	1000,
+	Math.floor(
+		ttlSeconds *
+			(renewRatio > 0 && renewRatio < 1 ? renewRatio : 0.8) *
+			1000,
+	),
+)
+
+const bacnetClient = new Bacnet({
+	apduTimeout: 5000,
+	interface: '0.0.0.0',
+	port: localPort,
+})
+
+let renewTimer: NodeJS.Timeout | null = null
+let registerInFlight = false
+
+const clearRenewTimer = () => {
+	if (renewTimer) clearTimeout(renewTimer)
+	renewTimer = null
+}
+
+const closeClient = () => {
+	clearRenewTimer()
+	bacnetClient.close()
+}
+
+const register = async () => {
+	if (registerInFlight) return
+	registerInFlight = true
+	try {
+		await bacnetClient.registerForeignDevice(
+			{ address: bbmdAddress },
+			ttlSeconds,
+		)
+		console.log(
+			`FDR success: bbmd=${bbmdAddress}, ttl=${ttlSeconds}s, next_renew_in=${Math.floor(renewDelayMs / 1000)}s`,
+		)
+		clearRenewTimer()
+		renewTimer = setTimeout(() => {
+			register().catch((err) =>
+				console.error(
+					`FDR renew failed: ${String((err as Error)?.message || err)}`,
+				),
+			)
+		}, renewDelayMs)
+	} catch (err) {
+		console.error(`FDR failed: ${String((err as Error)?.message || err)}`)
+	} finally {
+		registerInFlight = false
+	}
+}
+
+bacnetClient.on('listening', () => {
+	console.log(`BACnet transport listening on UDP ${localPort}`)
+	console.log(`Registering to BBMD ${bbmdAddress} ...`)
+	register().catch((err) =>
+		console.error(`FDR failed: ${String((err as Error)?.message || err)}`),
+	)
+})
+
+bacnetClient.on('bvlcResult', (content) => {
+	console.log(
+		`BVLC result from ${content?.header?.sender?.address}: ${content?.payload?.resultCode}`,
+	)
+})
+
+bacnetClient.on('error', (err: Error) => {
+	console.error(`BACnet error: ${err.message}`)
+})
+
+process.on('SIGINT', () => {
+	console.log('Stopping...')
+	closeClient()
+	process.exit(0)
+})
+
+process.on('SIGTERM', () => {
+	closeClient()
+	process.exit(0)
+})

src/lib/EventTypes.ts

@@ -21,6 +21,7 @@ import {
 	ListElementOperationPayload,
 	PrivateTransferPayload,
 	RegisterForeignDevicePayload,
+	BvlcResultPayload,
 	WhoHasPayload,
 	TimeSyncPayload,
 	IHavePayload,
@@ -180,6 +181,9 @@ export interface BACnetClientEvents {
 	privateTransfer: (
 		content: BaseEventContent & { payload: PrivateTransferPayload },
 	) => void
+	bvlcResult: (
+		content: BaseEventContent & { payload: BvlcResultPayload },
+	) => void
 	registerForeignDevice: (
 		content: BaseEventContent & { payload: RegisterForeignDevicePayload },
 	) => void

src/lib/bvlc.ts

@@ -2,11 +2,10 @@ import {
 	BVLL_TYPE_BACNET_IP,
 	BvlcResultPurpose,
 	BVLC_HEADER_LENGTH,
+	DEFAULT_BACNET_PORT,
 } from './enum'
 import { BvlcPacket } from './types'
 
-const DEFAULT_BACNET_PORT = 47808
-
 export const encode = (
 	buffer: Buffer,
 	func: number,
@@ -50,9 +49,12 @@ export const decode = (
 	buffer: Buffer,
 	_offset: number,
 ): BvlcPacket | undefined => {
+	if (buffer.length < BVLC_HEADER_LENGTH) return undefined
+
 	let len: number
 	const func = buffer[1]
 	const msgLength = (buffer[2] << 8) | (buffer[3] << 0)
+	if (msgLength < BVLC_HEADER_LENGTH) return undefined
 	if (buffer[0] !== BVLL_TYPE_BACNET_IP || buffer.length !== msgLength)
 		return undefined
 	let originatingIP = null
@@ -71,6 +73,7 @@ export const decode = (
 			len = 4
 			break
 		case BvlcResultPurpose.FORWARDED_NPDU:
+			if (msgLength < 10) return undefined
 			// Work out where the packet originally came from before the BBMD
 			// forwarded it to us, so we can tell the BBMD where to send any reply to.
 			const port = (buffer[8] << 8) | buffer[9]