handle_publish.c

/*
Copyright (c) 2009-2019 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 v1.0
and Eclipse Distribution License v1.0 which accompany this distribution.

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

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

#include "config.h"

#include <assert.h>
#include <stdio.h>
#include <string.h>

#include "mosquitto_broker_internal.h"
#include "mqtt3_protocol.h"
#include "memory_mosq.h"
#include "packet_mosq.h"
#include "read_handle.h"
#include "send_mosq.h"
#include "sys_tree.h"
#include "util_mosq.h"


int handle__publish(struct mosquitto_db *db, struct mosquitto *context)
{
	char *topic;
	mosquitto__payload_uhpa payload;
	uint32_t payloadlen;
	uint8_t dup, qos, retain;
	uint16_t mid = 0;
	int rc = 0;
	uint8_t header = context->in_packet.command;
	int res = 0;
	struct mosquitto_msg_store *stored = NULL;
	int len;
	int slen;
	char *topic_mount;
#ifdef WITH_BRIDGE
	char *topic_temp;
	int i;
	struct mosquitto__bridge_topic *cur_topic;
	bool match;
#endif

	payload.ptr = NULL;

	dup = (header & 0x08)>>3;
	qos = (header & 0x06)>>1;
	if(qos == 3){
		log__printf(NULL, MOSQ_LOG_INFO,
				"Invalid QoS in PUBLISH from %s, disconnecting.", context->id);
		return 1;
	}
	retain = (header & 0x01);

	if(packet__read_string(&context->in_packet, &topic, &slen)) return 1;
	if(!slen){
		/* Invalid publish topic, disconnect client. */
		mosquitto__free(topic);
		return 1;
	}

	if(mosquitto_validate_utf8(topic, slen) != MOSQ_ERR_SUCCESS){
		log__printf(NULL, MOSQ_LOG_INFO, "Client %s sent topic with invalid UTF-8, disconnecting.", context->id);
		mosquitto__free(topic);
		return 1;
	}

#ifdef WITH_BRIDGE
	if(context->bridge && context->bridge->topics && context->bridge->topic_remapping){
		for(i=0; i<context->bridge->topic_count; i++){
			cur_topic = &context->bridge->topics[i];
			if((cur_topic->direction == bd_both || cur_topic->direction == bd_in)
					&& (cur_topic->remote_prefix || cur_topic->local_prefix)){

				/* Topic mapping required on this topic if the message matches */

				rc = mosquitto_topic_matches_sub(cur_topic->remote_topic, topic, &match);
				if(rc){
					mosquitto__free(topic);
					return rc;
				}
				if(match){
					if(cur_topic->remote_prefix){
						/* This prefix needs removing. */
						if(!strncmp(cur_topic->remote_prefix, topic, strlen(cur_topic->remote_prefix))){
							topic_temp = mosquitto__strdup(topic+strlen(cur_topic->remote_prefix));
							if(!topic_temp){
								mosquitto__free(topic);
								return MOSQ_ERR_NOMEM;
							}
							mosquitto__free(topic);
							topic = topic_temp;
						}
					}

					if(cur_topic->local_prefix){
						/* This prefix needs adding. */
						len = strlen(topic) + strlen(cur_topic->local_prefix)+1;
						topic_temp = mosquitto__malloc(len+1);
						if(!topic_temp){
							mosquitto__free(topic);
							return MOSQ_ERR_NOMEM;
						}
						snprintf(topic_temp, len, "%s%s", cur_topic->local_prefix, topic);
						topic_temp[len] = '\0';

						mosquitto__free(topic);
						topic = topic_temp;
					}
					break;
				}
			}
		}
	}
#endif
	if(mosquitto_pub_topic_check(topic) != MOSQ_ERR_SUCCESS){
		/* Invalid publish topic, just swallow it. */
		mosquitto__free(topic);
		return 1;
	}

	if(qos > 0){
		if(packet__read_uint16(&context->in_packet, &mid)){
			mosquitto__free(topic);
			return 1;
		}
	}

	payloadlen = context->in_packet.remaining_length - context->in_packet.pos;
	G_PUB_BYTES_RECEIVED_INC(payloadlen);
	if(context->listener && context->listener->mount_point){
		len = strlen(context->listener->mount_point) + strlen(topic) + 1;
		topic_mount = mosquitto__malloc(len+1);
		if(!topic_mount){
			mosquitto__free(topic);
			return MOSQ_ERR_NOMEM;
		}
		snprintf(topic_mount, len, "%s%s", context->listener->mount_point, topic);
		topic_mount[len] = '\0';

		mosquitto__free(topic);
		topic = topic_mount;
	}

	if(payloadlen){
		if(db->config->message_size_limit && payloadlen > db->config->message_size_limit){
			log__printf(NULL, MOSQ_LOG_DEBUG, "Dropped too large PUBLISH from %s (d%d, q%d, r%d, m%d, '%s', ... (%ld bytes))", context->id, dup, qos, retain, mid, topic, (long)payloadlen);
			goto process_bad_message;
		}
		if(UHPA_ALLOC(payload, payloadlen+1) == 0){
			mosquitto__free(topic);
			return MOSQ_ERR_NOMEM;
		}
		if(packet__read_bytes(&context->in_packet, UHPA_ACCESS(payload, payloadlen), payloadlen)){
			mosquitto__free(topic);
			UHPA_FREE(payload, payloadlen);
			return 1;
		}
	}

	/* Check for topic access */
	rc = mosquitto_acl_check(db, context, topic, payloadlen, UHPA_ACCESS(payload, payloadlen), qos, retain, MOSQ_ACL_WRITE);
	if(rc == MOSQ_ERR_ACL_DENIED){
		log__printf(NULL, MOSQ_LOG_DEBUG, "Denied PUBLISH from %s (d%d, q%d, r%d, m%d, '%s', ... (%ld bytes))", context->id, dup, qos, retain, mid, topic, (long)payloadlen);
		goto process_bad_message;
	}else if(rc != MOSQ_ERR_SUCCESS){
		mosquitto__free(topic);
		UHPA_FREE(payload, payloadlen);
		return rc;
	}

	log__printf(NULL, MOSQ_LOG_DEBUG, "Received PUBLISH from %s (d%d, q%d, r%d, m%d, '%s', ... (%ld bytes))", context->id, dup, qos, retain, mid, topic, (long)payloadlen);
	if(qos > 0){
		db__message_store_find(context, mid, &stored);
	}
	if(!stored){
		if(qos == 0
				|| db__ready_for_flight(context, qos)
				|| db__ready_for_queue(context, qos)){

			dup = 0;
			if(db__message_store(db, context, mid, topic, qos, payloadlen, &payload, retain, &stored, 0)){
				return 1;
			}
		}else{
			/* Client isn't allowed any more incoming messages, so fail early */
			mosquitto__free(topic);
			UHPA_FREE(payload, payloadlen);
			if(qos == 1){
				return send__puback(context, mid);
			}else{
				return send__pubrec(context, mid);
			}
		}
	}else{
		mosquitto__free(topic);
		topic = stored->topic;
		dup = 1;
	}

	switch(qos){
		case 0:
			if(sub__messages_queue(db, context->id, topic, qos, retain, &stored)) rc = 1;
			break;
		case 1:
			if(sub__messages_queue(db, context->id, topic, qos, retain, &stored)) rc = 1;
			if(send__puback(context, mid)) rc = 1;
			break;
		case 2:
			if(!dup){
				res = db__message_insert(db, context, mid, mosq_md_in, qos, retain, stored);
			}else{
				res = 0;
			}
			/* db__message_insert() returns 2 to indicate dropped message
			 * due to queue. This isn't an error so don't disconnect them. */
			if(!res){
				if(send__pubrec(context, mid)) rc = 1;
			}else if(res == 1){
				rc = 1;
			}
			break;
	}

	return rc;
process_bad_message:
	mosquitto__free(topic);
	UHPA_FREE(payload, payloadlen);
	switch(qos){
		case 0:
			return MOSQ_ERR_SUCCESS;
		case 1:
			return send__puback(context, mid);
		case 2:
			db__message_store_find(context, mid, &stored);
			if(!stored){
				if(db__message_store(db, context, mid, NULL, qos, 0, NULL, false, &stored, 0)){
					return 1;
				}
				res = db__message_insert(db, context, mid, mosq_md_in, qos, false, stored);
			}else{
				res = 0;
			}
			if(!res){
				res = send__pubrec(context, mid);
			}
			return res;
	}
	return 1;
}