Add RTCP ECN packet

src/packets/RTCP/CompoundPacket.ts

@@ -18,6 +18,7 @@ import {
 } from './FeedbackPacket';
 import { NackPacket } from './NackPacket';
 import { SrReqPacket } from './SrReqPacket';
+import { EcnPacket } from './EcnPacket';
 import { PliPacket } from './PliPacket';
 import { SliPacket } from './SliPacket';
 import { RpsiPacket } from './RpsiPacket';
@@ -142,6 +143,13 @@ export class CompoundPacket extends Packet
 							break;
 						}
 
+						case RtpFeedbackMessageType.ECN:
+						{
+							packet = new EcnPacket(packetView);
+
+							break;
+						}
+
 						default:
 						{
 							packet = new GenericFeedbackPacket(packetView);

src/packets/RTCP/EcnPacket.ts

@@ -0,0 +1,299 @@
+import { RtcpPacketType } from './RtcpPacket';
+import {
+	FeedbackPacket,
+	RtpFeedbackMessageType,
+	FeedbackPacketDump,
+	FIXED_HEADER_LENGTH
+} from './FeedbackPacket';
+
+const ECN_PACKET_LENGTH = FIXED_HEADER_LENGTH + 20;
+
+/**
+ * RTCP ECN packet info dump.
+ *
+ * @category RTCP
+ */
+export type EcnPacketDump = FeedbackPacketDump &
+{
+	extendedHighestSequenceNumber: number;
+	ect0Counter: number;
+	ect1Counter: number;
+	ecnCeCounter: number;
+	nonEctCounter: number;
+	lostPacketsCounter: number;
+	duplicationCounter: number;
+};
+
+/**
+ * RTCP ECN packet (RTCP Transport Layer Feedback).
+ *
+ * ```text
+ *  0                   1                   2                   3
+ *  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |V=2|P|  FMT=8  |  PT=RTPFB=205 |          length=7             |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                  SSRC of packet sender                        |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * |                  SSRC of media source                         |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Extended Highest Sequence Number                              |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | ECT (0) Counter                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | ECT (1) Counter                                               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | ECN-CE Counter                | not-ECT Counter               |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * | Lost Packets Counter          | Duplication Counter           |
+ * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+ * ```
+ *
+ * @category RTCP
+ *
+ * @see
+ * - [RFC 6679 section 5.1](https://datatracker.ietf.org/doc/html/rfc6679#section-5.1)
+ */
+export class EcnPacket extends FeedbackPacket
+{
+	/**
+	 * @param view - If given it will be parsed. Otherwise an empty RTCP ECN
+	 *   packet will be created.
+	 *
+	 * @throws
+	 * - If given `view` does not contain a valid RTCP ECN packet.
+	 */
+	constructor(view?: DataView)
+	{
+		super(RtcpPacketType.RTPFB, RtpFeedbackMessageType.ECN, view);
+
+		if (!this.view)
+		{
+			this.view = new DataView(new ArrayBuffer(ECN_PACKET_LENGTH));
+
+			// Write version, packet type and feedback message type.
+			this.writeFixedHeader();
+
+			return;
+		}
+
+		// Position relative to the DataView byte offset.
+		let pos = 0;
+
+		// Move to the end.
+		pos += ECN_PACKET_LENGTH;
+
+		pos += this.padding;
+
+		// Ensure that view length and parsed length match.
+		if (pos !== this.view.byteLength)
+		{
+			throw new RangeError(
+				`parsed length (${pos} bytes) does not match view length (${this.view.byteLength} bytes)`
+			);
+		}
+	}
+
+	/**
+	 * Dump RTCP ECN packet info.
+	 */
+	dump(): EcnPacketDump
+	{
+		return {
+			...super.dump(),
+			extendedHighestSequenceNumber : this.getExtendedHighestSequenceNumber(),
+			ect0Counter                   : this.getEct0Counter(),
+			ect1Counter                   : this.getEct1Counter(),
+			ecnCeCounter                  : this.getEcnCeCounter(),
+			nonEctCounter                 : this.getNonEctCounter(),
+			lostPacketsCounter            : this.getLostPacketsCounter(),
+			duplicationCounter            : this.getDuplicationCounter()
+		};
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	getByteLength(): number
+	{
+		return ECN_PACKET_LENGTH + this.padding;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	serialize(buffer?: ArrayBuffer, byteOffset?: number): void
+	{
+		const view = this.serializeBase(buffer, byteOffset);
+		const uint8Array = new Uint8Array(
+			view.buffer,
+			view.byteOffset,
+			view.byteLength
+		);
+
+		// Position relative to the DataView byte offset.
+		let pos = 0;
+
+		// Move to FCI.
+		pos += FIXED_HEADER_LENGTH;
+
+		// Copy the entire FCI into the new buffer.
+		uint8Array.set(
+			new Uint8Array(
+				this.view.buffer,
+				this.view.byteOffset + pos,
+				ECN_PACKET_LENGTH - FIXED_HEADER_LENGTH
+			),
+			pos
+		);
+
+		pos += ECN_PACKET_LENGTH - FIXED_HEADER_LENGTH;
+
+		pos += this.padding;
+
+		// Assert that current position is equal than new buffer length.
+		if (pos !== view.byteLength)
+		{
+			throw new RangeError(
+				`filled length (${pos} bytes) is different than the available buffer size (${view.byteLength} bytes)`
+			);
+		}
+
+		// Update DataView.
+		this.view = view;
+
+		this.setSerializationNeeded(false);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	clone(
+		buffer?: ArrayBuffer,
+		byteOffset?: number,
+		serializationBuffer?: ArrayBuffer,
+		serializationByteOffset?: number
+	): EcnPacket
+	{
+		const view = this.cloneInternal(
+			buffer,
+			byteOffset,
+			serializationBuffer,
+			serializationByteOffset
+		);
+
+		return new EcnPacket(view);
+	}
+
+	/**
+	 * Get Extended Highest Sequence Number.
+	 */
+	getExtendedHighestSequenceNumber(): number
+	{
+		return this.view.getUint32(12);
+	}
+
+	/**
+	 * Set Extended Highest Sequence Number.
+	 */
+	setExtendedHighestSequenceNumber(sequenceNumber: number): void
+	{
+		this.view.setUint32(12, sequenceNumber);
+	}
+
+	/**
+	 * Get ECT (0) Counter.
+	 */
+	getEct0Counter(): number
+	{
+		return this.view.getUint32(16);
+	}
+
+	/**
+	 * Set ECT (0) Counter.
+	 */
+	setEct0Counter(counter: number): void
+	{
+		this.view.setUint32(16, counter);
+	}
+
+	/**
+	 * Get ECT (1) Counter.
+	 */
+	getEct1Counter(): number
+	{
+		return this.view.getUint32(20);
+	}
+
+	/**
+	 * Set ECT (1) Counter.
+	 */
+	setEct1Counter(counter: number): void
+	{
+		this.view.setUint32(20, counter);
+	}
+
+	/**
+	 * Get ECN-CE Counter.
+	 */
+	getEcnCeCounter(): number
+	{
+		return this.view.getUint16(24);
+	}
+
+	/**
+	 * Set ECN-CE Counter.
+	 */
+	setEcnCeCounter(counter: number): void
+	{
+		this.view.setUint16(24, counter);
+	}
+
+	/**
+	 * Get not-ECT Counter.
+	 */
+	getNonEctCounter(): number
+	{
+		return this.view.getUint16(26);
+	}
+
+	/**
+	 * Set not-ECT Counter.
+	 */
+	setNonEctCounter(counter: number): void
+	{
+		this.view.setUint16(26, counter);
+	}
+
+	/**
+	 * Get Lost Packets Counter.
+	 */
+	getLostPacketsCounter(): number
+	{
+		return this.view.getUint16(28);
+	}
+
+	/**
+	 * Set Lost Packets Counter.
+	 */
+	setLostPacketsCounter(counter: number): void
+	{
+		this.view.setUint16(28, counter);
+	}
+
+	/**
+	 * Get Duplication Counter.
+	 */
+	getDuplicationCounter(): number
+	{
+		return this.view.getUint16(30);
+	}
+
+	/**
+	 * Set Duplication Counter.
+	 */
+	setDuplicationCounter(counter: number): void
+	{
+		this.view.setUint16(30, counter);
+	}
+}

src/packets/RTCP/FeedbackPacket.ts

@@ -29,7 +29,11 @@ export enum RtpFeedbackMessageType
 	/**
 	 * Rapid Resynchronisation Request.
 	 */
-	SR_REQ = 5
+	SR_REQ = 5,
+	/**
+	 * Explicit Congestion Notification (ECN).
+	 */
+	ECN = 8
 }
 
 /**
@@ -100,6 +104,11 @@ function messageTypeToString(
 			return 'Rapid Resynchronisation Request';
 		}
 
+		case RtpFeedbackMessageType.ECN:
+		{
+			return 'Explicit Congestion Notification (ECN)';
+		}
+
 		case PsFeedbackMessageType.PLI:
 		{
 			return 'Picture Loss Indication';

src/packets/public.ts

@@ -85,6 +85,11 @@ export {
 	SrReqPacketDump
 } from './RTCP/SrReqPacket';
 
+export {
+	EcnPacket,
+	EcnPacketDump
+} from './RTCP/EcnPacket';
+
 export {
 	PliPacket,
 	PliPacketDump