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d6613e995b829c000af5348ec932ab76b222e87f
esp-mqtt/lib/mqtt_msg.c
Angus Gratton b9db8d9020 Use size_t for all lengths 
Previously, uint32_t and size_t were used interchangeably. These types are
interchangeable on Xtensa gcc (uint32_t == size_t == unsigned int), but not on most
other 32-bit gcc architectures (where uint32_t == unsigned long, size_t ==
unsigned int).
2020-10-09 16:33:12 +11:00

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/*
* Copyright (c) 2014, Stephen Robinson
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
*
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the copyright holder nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*
*/
#include <string.h>
#include "mqtt_msg.h"
#include "mqtt_config.h"
#include "platform.h"
#define MQTT_MAX_FIXED_HEADER_SIZE 5
#define MQTT_3_1_VARIABLE_HEADER_SIZE 12
#define MQTT_3_1_1_VARIABLE_HEADER_SIZE 10
enum mqtt_connect_flag {
MQTT_CONNECT_FLAG_USERNAME = 1 << 7,
MQTT_CONNECT_FLAG_PASSWORD = 1 << 6,
MQTT_CONNECT_FLAG_WILL_RETAIN = 1 << 5,
MQTT_CONNECT_FLAG_WILL = 1 << 2,
MQTT_CONNECT_FLAG_CLEAN_SESSION = 1 << 1
};
static int append_string(mqtt_connection_t *connection, const char *string, int len)
{
if (connection->message.length + len + 2 > connection->buffer_length) {
return -1;
}
connection->buffer[connection->message.length++] = len >> 8;
connection->buffer[connection->message.length++] = len & 0xff;
memcpy(connection->buffer + connection->message.length, string, len);
connection->message.length += len;
return len + 2;
}
static uint16_t append_message_id(mqtt_connection_t *connection, uint16_t message_id)
{
// If message_id is zero then we should assign one, otherwise
// we'll use the one supplied by the caller
while (message_id == 0) {
message_id = platform_random(65535);
}
if (connection->message.length + 2 > connection->buffer_length) {
return 0;
}
connection->buffer[connection->message.length++] = message_id >> 8;
connection->buffer[connection->message.length++] = message_id & 0xff;
return message_id;
}
static int init_message(mqtt_connection_t *connection)
{
connection->message.length = MQTT_MAX_FIXED_HEADER_SIZE;
return MQTT_MAX_FIXED_HEADER_SIZE;
}
static mqtt_message_t *fail_message(mqtt_connection_t *connection)
{
connection->message.data = connection->buffer;
connection->message.length = 0;
return &connection->message;
}
static mqtt_message_t *fini_message(mqtt_connection_t *connection, int type, int dup, int qos, int retain)
{
int message_length = connection->message.length - MQTT_MAX_FIXED_HEADER_SIZE;
int total_length = message_length;
int encoded_length = 0;
uint8_t encoded_lens[4] = {0};
// Check if we have fragmented message and update total_len
if (connection->message.fragmented_msg_total_length) {
total_length = connection->message.fragmented_msg_total_length - MQTT_MAX_FIXED_HEADER_SIZE;
}
// Encode MQTT message length
int len_bytes = 0; // size of encoded message length
do {
encoded_length = total_length % 128;
total_length /= 128;
if (total_length > 0) {
encoded_length |= 0x80;
}
encoded_lens[len_bytes] = encoded_length;
len_bytes++;
} while (total_length > 0);
// Sanity check for MQTT header
if (len_bytes + 1 > MQTT_MAX_FIXED_HEADER_SIZE) {
return fail_message(connection);
}
// Save the header bytes
connection->message.length = message_length + len_bytes + 1; // msg len + encoded_size len + type (1 byte)
int offs = MQTT_MAX_FIXED_HEADER_SIZE - 1 - len_bytes;
connection->message.data = connection->buffer + offs;
connection->message.fragmented_msg_data_offset -= offs;
// type byte
connection->buffer[offs++] = ((type & 0x0f) << 4) | ((dup & 1) << 3) | ((qos & 3) << 1) | (retain & 1);
// length bytes
for (int j = 0; j < len_bytes; j++) {
connection->buffer[offs++] = encoded_lens[j];
}
return &connection->message;
}
void mqtt_msg_init(mqtt_connection_t *connection, uint8_t *buffer, size_t buffer_length)
{
memset(connection, 0, sizeof(mqtt_connection_t));
connection->buffer = buffer;
connection->buffer_length = buffer_length;
}
size_t mqtt_get_total_length(const uint8_t *buffer, size_t length, int *fixed_size_len)
{
int i;
size_t totlen = 0;
for (i = 1; i < length; ++i) {
totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
if ((buffer[i] & 0x80) == 0) {
++i;
break;
}
}
totlen += i;
if (fixed_size_len) {
*fixed_size_len = i;
}
return totlen;
}
bool mqtt_header_complete(uint8_t *buffer, size_t buffer_length)
{
uint16_t i;
uint16_t topiclen;
for (i = 1; i < MQTT_MAX_FIXED_HEADER_SIZE; ++i) {
if (i >= buffer_length) {
return false;
}
if ((buffer[i] & 0x80) == 0) {
++i;
break;
}
}
// i is now the length of the fixed header
if (i + 2 >= buffer_length) {
return false;
}
topiclen = buffer[i++] << 8;
topiclen |= buffer[i++];
i += topiclen;
if (mqtt_get_qos(buffer) > 0) {
i += 2;
}
// i is now the length of the fixed + variable header
return buffer_length >= i;
}
char *mqtt_get_publish_topic(uint8_t *buffer, size_t *length)
{
int i;
int totlen = 0;
int topiclen;
for (i = 1; i < *length; ++i) {
totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
if ((buffer[i] & 0x80) == 0) {
++i;
break;
}
}
totlen += i;
if (i + 2 >= *length) {
return NULL;
}
topiclen = buffer[i++] << 8;
topiclen |= buffer[i++];
if (i + topiclen > *length) {
return NULL;
}
*length = topiclen;
return (char *)(buffer + i);
}
char *mqtt_get_publish_data(uint8_t *buffer, size_t *length)
{
int i;
int totlen = 0;
int topiclen;
int blength = *length;
*length = 0;
for (i = 1; i < blength; ++i) {
totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
if ((buffer[i] & 0x80) == 0) {
++i;
break;
}
}
totlen += i;
if (i + 2 >= blength) {
return NULL;
}
topiclen = buffer[i++] << 8;
topiclen |= buffer[i++];
if (i + topiclen >= blength) {
return NULL;
}
i += topiclen;
if (mqtt_get_qos(buffer) > 0) {
if (i + 2 >= blength) {
return NULL;
}
i += 2;
}
if (totlen < i) {
return NULL;
}
if (totlen <= blength) {
*length = totlen - i;
} else {
*length = blength - i;
}
return (char *)(buffer + i);
}
uint16_t mqtt_get_id(uint8_t *buffer, size_t length)
{
if (length < 1) {
return 0;
}
switch (mqtt_get_type(buffer)) {
case MQTT_MSG_TYPE_PUBLISH: {
int i;
int topiclen;
for (i = 1; i < length; ++i) {
if ((buffer[i] & 0x80) == 0) {
++i;
break;
}
}
if (i + 2 >= length) {
return 0;
}
topiclen = buffer[i++] << 8;
topiclen |= buffer[i++];
if (i + topiclen > length) {
return 0;
}
i += topiclen;
if (mqtt_get_qos(buffer) > 0) {
if (i + 2 > length) {
return 0;
}
//i += 2;
} else {
return 0;
}
return (buffer[i] << 8) | buffer[i + 1];
}
case MQTT_MSG_TYPE_PUBACK:
case MQTT_MSG_TYPE_PUBREC:
case MQTT_MSG_TYPE_PUBREL:
case MQTT_MSG_TYPE_PUBCOMP:
case MQTT_MSG_TYPE_SUBACK:
case MQTT_MSG_TYPE_UNSUBACK:
case MQTT_MSG_TYPE_SUBSCRIBE:
case MQTT_MSG_TYPE_UNSUBSCRIBE: {
// This requires the remaining length to be encoded in 1 byte,
// which it should be.
if (length >= 4 && (buffer[1] & 0x80) == 0) {
return (buffer[2] << 8) | buffer[3];
} else {
return 0;
}
}
default:
return 0;
}
}
mqtt_message_t *mqtt_msg_connect(mqtt_connection_t *connection, mqtt_connect_info_t *info)
{
init_message(connection);
int header_len;
if (info->protocol_ver == MQTT_PROTOCOL_V_3_1) {
header_len = MQTT_3_1_VARIABLE_HEADER_SIZE;
} else {
header_len = MQTT_3_1_1_VARIABLE_HEADER_SIZE;
}
if (connection->message.length + header_len > connection->buffer_length) {
return fail_message(connection);
}
char* variable_header = (void *)(connection->buffer + connection->message.length);
connection->message.length += header_len;
int header_idx = 0;
variable_header[header_idx++] = 0; // Variable header length MSB
if (info->protocol_ver == MQTT_PROTOCOL_V_3_1) {
variable_header[header_idx++] = 6; // Variable header length LSB
memcpy(&variable_header[header_idx], "MQIsdp", 6); // Protocol name
header_idx = header_idx + 6;
variable_header[header_idx++] = 3; // Protocol version
} else {
/* Defaults to protocol version 3.1.1 values */
variable_header[header_idx++] = 4; // Variable header length LSB
memcpy(&variable_header[header_idx], "MQTT", 4); // Protocol name
header_idx = header_idx + 4;
variable_header[header_idx++] = 4; // Protocol version
}
int flags_offset = header_idx;
variable_header[header_idx++] = 0; // Flags
variable_header[header_idx++] = info->keepalive >> 8; // Keep-alive MSB
variable_header[header_idx] = info->keepalive & 0xff; // Keep-alive LSB
if (info->clean_session) {
variable_header[flags_offset] |= MQTT_CONNECT_FLAG_CLEAN_SESSION;
}
if (info->client_id != NULL && info->client_id[0] != '\0') {
if (append_string(connection, info->client_id, strlen(info->client_id)) < 0) {
return fail_message(connection);
}
} else {
return fail_message(connection);
}
if (info->will_topic != NULL && info->will_topic[0] != '\0') {
if (append_string(connection, info->will_topic, strlen(info->will_topic)) < 0) {
return fail_message(connection);
}
if (append_string(connection, info->will_message, info->will_length) < 0) {
return fail_message(connection);
}
variable_header[flags_offset] |= MQTT_CONNECT_FLAG_WILL;
if (info->will_retain) {
variable_header[flags_offset] |= MQTT_CONNECT_FLAG_WILL_RETAIN;
}
variable_header[flags_offset] |= (info->will_qos & 3) << 3;
}
if (info->username != NULL && info->username[0] != '\0') {
if (append_string(connection, info->username, strlen(info->username)) < 0) {
return fail_message(connection);
}
variable_header[flags_offset] |= MQTT_CONNECT_FLAG_USERNAME;
}
if (info->password != NULL && info->password[0] != '\0') {
if (append_string(connection, info->password, strlen(info->password)) < 0) {
return fail_message(connection);
}
variable_header[flags_offset] |= MQTT_CONNECT_FLAG_PASSWORD;
}
return fini_message(connection, MQTT_MSG_TYPE_CONNECT, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_publish(mqtt_connection_t *connection, const char *topic, const char *data, int data_length, int qos, int retain, uint16_t *message_id)
{
init_message(connection);
if (topic == NULL || topic[0] == '\0') {
return fail_message(connection);
}
if (append_string(connection, topic, strlen(topic)) < 0) {
return fail_message(connection);
}
if (data == NULL && data_length > 0) {
return fail_message(connection);
}
if (qos > 0) {
if ((*message_id = append_message_id(connection, 0)) == 0) {
return fail_message(connection);
}
} else {
*message_id = 0;
}
if (connection->message.length + data_length > connection->buffer_length) {
// Not enough size in buffer -> fragment this message
connection->message.fragmented_msg_data_offset = connection->message.length;
memcpy(connection->buffer + connection->message.length, data, connection->buffer_length - connection->message.length);
connection->message.length = connection->buffer_length;
connection->message.fragmented_msg_total_length = data_length + connection->message.fragmented_msg_data_offset;
} else {
if (data != NULL)
{
memcpy(connection->buffer + connection->message.length, data, data_length);
connection->message.length += data_length;
}
connection->message.fragmented_msg_total_length = 0;
}
return fini_message(connection, MQTT_MSG_TYPE_PUBLISH, 0, qos, retain);
}
mqtt_message_t *mqtt_msg_puback(mqtt_connection_t *connection, uint16_t message_id)
{
init_message(connection);
if (append_message_id(connection, message_id) == 0) {
return fail_message(connection);
}
return fini_message(connection, MQTT_MSG_TYPE_PUBACK, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_pubrec(mqtt_connection_t *connection, uint16_t message_id)
{
init_message(connection);
if (append_message_id(connection, message_id) == 0) {
return fail_message(connection);
}
return fini_message(connection, MQTT_MSG_TYPE_PUBREC, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_pubrel(mqtt_connection_t *connection, uint16_t message_id)
{
init_message(connection);
if (append_message_id(connection, message_id) == 0) {
return fail_message(connection);
}
return fini_message(connection, MQTT_MSG_TYPE_PUBREL, 0, 1, 0);
}
mqtt_message_t *mqtt_msg_pubcomp(mqtt_connection_t *connection, uint16_t message_id)
{
init_message(connection);
if (append_message_id(connection, message_id) == 0) {
return fail_message(connection);
}
return fini_message(connection, MQTT_MSG_TYPE_PUBCOMP, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_subscribe(mqtt_connection_t *connection, const char *topic, int qos, uint16_t *message_id)
{
init_message(connection);
if (topic == NULL || topic[0] == '\0') {
return fail_message(connection);
}
if ((*message_id = append_message_id(connection, 0)) == 0) {
return fail_message(connection);
}
if (append_string(connection, topic, strlen(topic)) < 0) {
return fail_message(connection);
}
if (connection->message.length + 1 > connection->buffer_length) {
return fail_message(connection);
}
connection->buffer[connection->message.length++] = qos;
return fini_message(connection, MQTT_MSG_TYPE_SUBSCRIBE, 0, 1, 0);
}
mqtt_message_t *mqtt_msg_unsubscribe(mqtt_connection_t *connection, const char *topic, uint16_t *message_id)
{
init_message(connection);
if (topic == NULL || topic[0] == '\0') {
return fail_message(connection);
}
if ((*message_id = append_message_id(connection, 0)) == 0) {
return fail_message(connection);
}
if (append_string(connection, topic, strlen(topic)) < 0) {
return fail_message(connection);
}
return fini_message(connection, MQTT_MSG_TYPE_UNSUBSCRIBE, 0, 1, 0);
}
mqtt_message_t *mqtt_msg_pingreq(mqtt_connection_t *connection)
{
init_message(connection);
return fini_message(connection, MQTT_MSG_TYPE_PINGREQ, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_pingresp(mqtt_connection_t *connection)
{
init_message(connection);
return fini_message(connection, MQTT_MSG_TYPE_PINGRESP, 0, 0, 0);
}
mqtt_message_t *mqtt_msg_disconnect(mqtt_connection_t *connection)
{
init_message(connection);
return fini_message(connection, MQTT_MSG_TYPE_DISCONNECT, 0, 0, 0);
}
/*
* check flags: [MQTT-2.2.2-1], [MQTT-2.2.2-2]
* returns 0 if flags are invalid, otherwise returns 1
*/
int mqtt_has_valid_msg_hdr(uint8_t *buffer, size_t length)
{
int qos, dup;
if (length < 1) {
return 0;
}
switch (mqtt_get_type(buffer)) {
case MQTT_MSG_TYPE_CONNECT:
case MQTT_MSG_TYPE_CONNACK:
case MQTT_MSG_TYPE_PUBACK:
case MQTT_MSG_TYPE_PUBREC:
case MQTT_MSG_TYPE_PUBCOMP:
case MQTT_MSG_TYPE_SUBACK:
case MQTT_MSG_TYPE_UNSUBACK:
case MQTT_MSG_TYPE_PINGREQ:
case MQTT_MSG_TYPE_PINGRESP:
case MQTT_MSG_TYPE_DISCONNECT:
return (buffer[0] & 0x0f) == 0; /* all flag bits are 0 */
case MQTT_MSG_TYPE_PUBREL:
case MQTT_MSG_TYPE_SUBSCRIBE:
case MQTT_MSG_TYPE_UNSUBSCRIBE:
return (buffer[0] & 0x0f) == 0x02; /* only bit 1 is set */
case MQTT_MSG_TYPE_PUBLISH:
qos = mqtt_get_qos(buffer);
dup = mqtt_get_dup(buffer);
/*
* there is no qos=3 [MQTT-3.3.1-4]
* dup flag must be set to 0 for all qos=0 messages [MQTT-3.3.1-2]
*/
return (qos < 3) && ((qos > 0) || (dup == 0));
default:
return 0;
}
}
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