mosquitto/include/mqtt_protocol.h

/*
Copyright (c) 2009-2020 Roger Light <roger@atchoo.org>

All rights reserved. This program and the accompanying materials
are made available under the terms of the Eclipse Public License 2.0
and Eclipse Distribution License v1.0 which accompany this distribution.

The Eclipse Public License is available at
   https://www.eclipse.org/legal/epl-2.0/
and the Eclipse Distribution License is available at
  http://www.eclipse.org/org/documents/edl-v10.php.

Contributors:
   Roger Light - initial implementation and documentation.
*/

#ifndef MQTT_PROTOCOL_H
#define MQTT_PROTOCOL_H

#define PROTOCOL_NAME_v31 "MQIsdp"
#define PROTOCOL_VERSION_v31 3

#define PROTOCOL_NAME "MQTT"

#define PROTOCOL_VERSION_v311 4
#define PROTOCOL_VERSION_v5 5


/* Message types */
#define CMD_CONNECT 0x10U
#define CMD_CONNACK 0x20U
#define CMD_PUBLISH 0x30U
#define CMD_PUBACK 0x40U
#define CMD_PUBREC 0x50U
#define CMD_PUBREL 0x60U
#define CMD_PUBCOMP 0x70U
#define CMD_SUBSCRIBE 0x80U
#define CMD_SUBACK 0x90U
#define CMD_UNSUBSCRIBE 0xA0U
#define CMD_UNSUBACK 0xB0U
#define CMD_PINGREQ 0xC0U
#define CMD_PINGRESP 0xD0U
#define CMD_DISCONNECT 0xE0U
#define CMD_AUTH 0xF0U

/* Mosquitto only: for distinguishing CONNECT and WILL properties */
#define CMD_WILL 0x100

enum mqtt311_connack_codes {
	CONNACK_ACCEPTED = 0,
	CONNACK_REFUSED_PROTOCOL_VERSION = 1,
	CONNACK_REFUSED_IDENTIFIER_REJECTED = 2,
	CONNACK_REFUSED_SERVER_UNAVAILABLE = 3,
	CONNACK_REFUSED_BAD_USERNAME_PASSWORD = 4,
	CONNACK_REFUSED_NOT_AUTHORIZED = 5,
};


enum mqtt5_return_codes {
	MQTT_RC_SUCCESS = 0,						/* CONNACK, PUBACK, PUBREC, PUBREL, PUBCOMP, UNSUBACK, AUTH */
	MQTT_RC_NORMAL_DISCONNECTION = 0,			/* DISCONNECT */
	MQTT_RC_GRANTED_QOS0 = 0,					/* SUBACK */
	MQTT_RC_GRANTED_QOS1 = 1,					/* SUBACK */
	MQTT_RC_GRANTED_QOS2 = 2,					/* SUBACK */
	MQTT_RC_DISCONNECT_WITH_WILL_MSG = 4,		/* DISCONNECT */
	MQTT_RC_NO_MATCHING_SUBSCRIBERS = 16,		/* PUBACK, PUBREC */
	MQTT_RC_NO_SUBSCRIPTION_EXISTED = 17,		/* UNSUBACK */
	MQTT_RC_CONTINUE_AUTHENTICATION = 24,		/* AUTH */
	MQTT_RC_REAUTHENTICATE = 25,				/* AUTH */

	MQTT_RC_UNSPECIFIED = 128,					/* CONNACK, PUBACK, PUBREC, SUBACK, UNSUBACK, DISCONNECT */
	MQTT_RC_MALFORMED_PACKET = 129,				/* CONNACK, DISCONNECT */
	MQTT_RC_PROTOCOL_ERROR = 130,				/* DISCONNECT */
	MQTT_RC_IMPLEMENTATION_SPECIFIC = 131,		/* CONNACK, PUBACK, PUBREC, SUBACK, UNSUBACK, DISCONNECT */
	MQTT_RC_UNSUPPORTED_PROTOCOL_VERSION = 132,	/* CONNACK */
	MQTT_RC_CLIENTID_NOT_VALID = 133,			/* CONNACK */
	MQTT_RC_BAD_USERNAME_OR_PASSWORD = 134,		/* CONNACK */
	MQTT_RC_NOT_AUTHORIZED = 135,				/* CONNACK, PUBACK, PUBREC, SUBACK, UNSUBACK, DISCONNECT */
	MQTT_RC_SERVER_UNAVAILABLE = 136,			/* CONNACK */
	MQTT_RC_SERVER_BUSY = 137,					/* CONNACK, DISCONNECT */
	MQTT_RC_BANNED = 138,						/* CONNACK */
	MQTT_RC_SERVER_SHUTTING_DOWN = 139,			/* DISCONNECT */
	MQTT_RC_BAD_AUTHENTICATION_METHOD = 140,	/* CONNACK */
	MQTT_RC_KEEP_ALIVE_TIMEOUT = 141,			/* DISCONNECT */
	MQTT_RC_SESSION_TAKEN_OVER = 142,			/* DISCONNECT */
	MQTT_RC_TOPIC_FILTER_INVALID = 143,			/* SUBACK, UNSUBACK, DISCONNECT */
	MQTT_RC_TOPIC_NAME_INVALID = 144,			/* CONNACK, PUBACK, PUBREC, DISCONNECT */
	MQTT_RC_PACKET_ID_IN_USE = 145,				/* PUBACK, SUBACK, UNSUBACK */
	MQTT_RC_PACKET_ID_NOT_FOUND = 146,			/* PUBREL, PUBCOMP */
	MQTT_RC_RECEIVE_MAXIMUM_EXCEEDED = 147,		/* DISCONNECT */
	MQTT_RC_TOPIC_ALIAS_INVALID = 148,			/* DISCONNECT */
	MQTT_RC_PACKET_TOO_LARGE = 149,				/* CONNACK, PUBACK, PUBREC, DISCONNECT */
	MQTT_RC_MESSAGE_RATE_TOO_HIGH = 150,		/* DISCONNECT */
	MQTT_RC_QUOTA_EXCEEDED = 151,				/* PUBACK, PUBREC, SUBACK, DISCONNECT */
	MQTT_RC_ADMINISTRATIVE_ACTION = 152,		/* DISCONNECT */
	MQTT_RC_PAYLOAD_FORMAT_INVALID = 153,		/* CONNACK, DISCONNECT */
	MQTT_RC_RETAIN_NOT_SUPPORTED = 154,			/* CONNACK, DISCONNECT */
	MQTT_RC_QOS_NOT_SUPPORTED = 155,			/* CONNACK, DISCONNECT */
	MQTT_RC_USE_ANOTHER_SERVER = 156,			/* CONNACK, DISCONNECT */
	MQTT_RC_SERVER_MOVED = 157,					/* CONNACK, DISCONNECT */
	MQTT_RC_SHARED_SUBS_NOT_SUPPORTED = 158,	/* SUBACK, DISCONNECT */
	MQTT_RC_CONNECTION_RATE_EXCEEDED = 159,		/* CONNACK, DISCONNECT */
	MQTT_RC_MAXIMUM_CONNECT_TIME = 160,			/* DISCONNECT */
	MQTT_RC_SUBSCRIPTION_IDS_NOT_SUPPORTED = 161, /* SUBACK, DISCONNECT */
	MQTT_RC_WILDCARD_SUBS_NOT_SUPPORTED = 162,	/* SUBACK, DISCONNECT */
};

/* Enum: mqtt5_property
 * Options for use with MQTTv5 properties.
 * Options:
 *
 *	MQTT_PROP_PAYLOAD_FORMAT_INDICATOR - property option.
 *	MQTT_PROP_MESSAGE_EXPIRY_INTERVAL - property option.
 *	MQTT_PROP_CONTENT_TYPE - property option.
 *	MQTT_PROP_RESPONSE_TOPIC - property option.
 *	MQTT_PROP_CORRELATION_DATA - property option.
 *	MQTT_PROP_SUBSCRIPTION_IDENTIFIER - property option.
 *	MQTT_PROP_SESSION_EXPIRY_INTERVAL - property option.
 *	MQTT_PROP_ASSIGNED_CLIENT_IDENTIFIER - property option.
 *	MQTT_PROP_SERVER_KEEP_ALIVE - property option.
 *	MQTT_PROP_AUTHENTICATION_METHOD - property option.
 *	MQTT_PROP_AUTHENTICATION_DATA - property option.
 *	MQTT_PROP_REQUEST_PROBLEM_INFORMATION - property option.
 *	MQTT_PROP_WILL_DELAY_INTERVAL - property option.
 *	MQTT_PROP_REQUEST_RESPONSE_INFORMATION - property option.
 *	MQTT_PROP_RESPONSE_INFORMATION - property option.
 *	MQTT_PROP_SERVER_REFERENCE - property option.
 *	MQTT_PROP_REASON_STRING - property option.
 *	MQTT_PROP_RECEIVE_MAXIMUM - property option.
 *	MQTT_PROP_TOPIC_ALIAS_MAXIMUM - property option.
 *	MQTT_PROP_TOPIC_ALIAS - property option.
 *	MQTT_PROP_MAXIMUM_QOS - property option.
 *	MQTT_PROP_RETAIN_AVAILABLE - property option.
 *	MQTT_PROP_USER_PROPERTY - property option.
 *	MQTT_PROP_MAXIMUM_PACKET_SIZE - property option.
 *	MQTT_PROP_WILDCARD_SUB_AVAILABLE - property option.
 *	MQTT_PROP_SUBSCRIPTION_ID_AVAILABLE - property option.
 *	MQTT_PROP_SHARED_SUB_AVAILABLE - property option.
 */
enum mqtt5_property {
	MQTT_PROP_PAYLOAD_FORMAT_INDICATOR = 1,		/* Byte :				PUBLISH, Will Properties */
	MQTT_PROP_MESSAGE_EXPIRY_INTERVAL = 2,		/* 4 byte int :			PUBLISH, Will Properties */
	MQTT_PROP_CONTENT_TYPE = 3,					/* UTF-8 string :		PUBLISH, Will Properties */
	MQTT_PROP_RESPONSE_TOPIC = 8,				/* UTF-8 string :		PUBLISH, Will Properties */
	MQTT_PROP_CORRELATION_DATA = 9,				/* Binary Data :		PUBLISH, Will Properties */
	MQTT_PROP_SUBSCRIPTION_IDENTIFIER = 11,		/* Variable byte int :	PUBLISH, SUBSCRIBE */
	MQTT_PROP_SESSION_EXPIRY_INTERVAL = 17,		/* 4 byte int :			CONNECT, CONNACK, DISCONNECT */
	MQTT_PROP_ASSIGNED_CLIENT_IDENTIFIER = 18,	/* UTF-8 string :		CONNACK */
	MQTT_PROP_SERVER_KEEP_ALIVE = 19,			/* 2 byte int :			CONNACK */
	MQTT_PROP_AUTHENTICATION_METHOD = 21,		/* UTF-8 string :		CONNECT, CONNACK, AUTH */
	MQTT_PROP_AUTHENTICATION_DATA = 22,			/* Binary Data :		CONNECT, CONNACK, AUTH */
	MQTT_PROP_REQUEST_PROBLEM_INFORMATION = 23,	/* Byte :				CONNECT */
	MQTT_PROP_WILL_DELAY_INTERVAL = 24,			/* 4 byte int :			Will properties */
	MQTT_PROP_REQUEST_RESPONSE_INFORMATION = 25,/* Byte :				CONNECT */
	MQTT_PROP_RESPONSE_INFORMATION = 26,		/* UTF-8 string :		CONNACK */
	MQTT_PROP_SERVER_REFERENCE = 28,			/* UTF-8 string :		CONNACK, DISCONNECT */
	MQTT_PROP_REASON_STRING = 31,				/* UTF-8 string :		All except Will properties */
	MQTT_PROP_RECEIVE_MAXIMUM = 33,				/* 2 byte int :			CONNECT, CONNACK */
	MQTT_PROP_TOPIC_ALIAS_MAXIMUM = 34,			/* 2 byte int :			CONNECT, CONNACK */
	MQTT_PROP_TOPIC_ALIAS = 35,					/* 2 byte int :			PUBLISH */
	MQTT_PROP_MAXIMUM_QOS = 36,					/* Byte :				CONNACK */
	MQTT_PROP_RETAIN_AVAILABLE = 37,			/* Byte :				CONNACK */
	MQTT_PROP_USER_PROPERTY = 38,				/* UTF-8 string pair :	All */
	MQTT_PROP_MAXIMUM_PACKET_SIZE = 39,			/* 4 byte int :			CONNECT, CONNACK */
	MQTT_PROP_WILDCARD_SUB_AVAILABLE = 40,		/* Byte :				CONNACK */
	MQTT_PROP_SUBSCRIPTION_ID_AVAILABLE = 41,	/* Byte :				CONNACK */
	MQTT_PROP_SHARED_SUB_AVAILABLE = 42,		/* Byte :				CONNACK */
};

enum mqtt5_property_type {
	MQTT_PROP_TYPE_BYTE = 1,
	MQTT_PROP_TYPE_INT16 = 2,
	MQTT_PROP_TYPE_INT32 = 3,
	MQTT_PROP_TYPE_VARINT = 4,
	MQTT_PROP_TYPE_BINARY = 5,
	MQTT_PROP_TYPE_STRING = 6,
	MQTT_PROP_TYPE_STRING_PAIR = 7
};

/* Enum: mqtt5_sub_options
 * Options for use with MQTTv5 subscriptions.
 *
 * MQTT_SUB_OPT_NO_LOCAL - with this option set, if this client publishes to
 * a topic to which it is subscribed, the broker will not publish the
 * message back to the client.
 *
 * MQTT_SUB_OPT_RETAIN_AS_PUBLISHED - with this option set, messages
 * published for this subscription will keep the retain flag as was set by
 * the publishing client. The default behaviour without this option set has
 * the retain flag indicating whether a message is fresh/stale.
 *
 * MQTT_SUB_OPT_SEND_RETAIN_ALWAYS - with this option set, pre-existing
 * retained messages are sent as soon as the subscription is made, even
 * if the subscription already exists. This is the default behaviour, so
 * it is not necessary to set this option.
 *
 * MQTT_SUB_OPT_SEND_RETAIN_NEW - with this option set, pre-existing retained
 * messages for this subscription will be sent when the subscription is made,
 * but only if the subscription does not already exist.
 *
 * MQTT_SUB_OPT_SEND_RETAIN_NEVER - with this option set, pre-existing
 * retained messages will never be sent for this subscription.
 */
enum mqtt5_sub_options {
	MQTT_SUB_OPT_NO_LOCAL = 0x04,
	MQTT_SUB_OPT_RETAIN_AS_PUBLISHED = 0x08,
	MQTT_SUB_OPT_SEND_RETAIN_ALWAYS = 0x00,
	MQTT_SUB_OPT_SEND_RETAIN_NEW = 0x10,
	MQTT_SUB_OPT_SEND_RETAIN_NEVER = 0x20,
};

#define MQTT_MAX_PAYLOAD 268435455U

#endif