// Return packet type. If no packet avilable, return FAILURE, or READ_ERROR if timeout
static int read_packet(mqtt_client_t* c, mqtt_timer_t* timer)
{
int rc = MQTT_FAILURE;
mqtt_header_t header = {0};
int len = 0;
int rem_len = 0;
/* 1. read the header byte. This has the packet type in it */
if (c->ipstack->mqttread(c->ipstack, c->readbuf, 1, mqtt_timer_left_ms(timer)) != 1)
goto exit;
len = 1;
/* 2. read the remaining length. This is variable in itself */
len += decode_packet(c, &rem_len, mqtt_timer_left_ms(timer));
if (len <= 1 || len + rem_len > c->readbuf_size) /* if packet is too big to fit in our readbuf, abort */
{
rc = MQTT_READ_ERROR;
goto exit;
}
mqtt_packet_encode(c->readbuf + 1, rem_len); /* put the original remaining length back into the buffer */
/* 3. read the rest of the buffer using a callback to supply the rest of the data */
if (rem_len > 0 && (c->ipstack->mqttread(c->ipstack, c->readbuf + len, rem_len, mqtt_timer_left_ms(timer)) != rem_len))
{
rc = MQTT_READ_ERROR;
goto exit;
}
header.byte = c->readbuf[0];
rc = header.bits.type;
exit:
return rc;
}
//--------------------------------------------
void mqtt_pingresp_encode(unsigned char **buf, size_t *size)
{
mqtt_fixed_header_t fixhdr;
fixhdr.msg_type = MQTT_PINGRESP;
fixhdr.dup_flag = 0;
fixhdr.qos_level = 0;
fixhdr.retain = 0;
fixhdr.rem_len = 0;
mqtt_packet_encode(&fixhdr, buf, size);
}
//--------------------------------------------
void mqtt_suback_encode(unsigned char **buf, size_t *size, mqtt_suback_header_t *suback)
{
mqtt_fixed_header_t fixhdr;
fixhdr.msg_type = MQTT_SUBACK;
fixhdr.dup_flag = 0;
fixhdr.qos_level = 0;
fixhdr.retain = 0;
fixhdr.rem_len = (uint32_t)(2 + suback->qos_size);
fixhdr.rem_buf = (unsigned char *)malloc(fixhdr.rem_len);
*(uint16_t *)&fixhdr.rem_buf[0] = htons(suback->msg_id);
memcpy(&fixhdr.rem_buf[2], suback->qos_buf, suback->qos_size);
mqtt_packet_encode(&fixhdr, buf, size);
}
//--------------------------------------------
void mqtt_connack_encode(unsigned char **buf, size_t *size, mqtt_connack_return_code_t code)
{
mqtt_fixed_header_t fixhdr;
fixhdr.msg_type = MQTT_CONNACK;
fixhdr.dup_flag = 0;
fixhdr.qos_level = 0;
fixhdr.retain = 0;
fixhdr.rem_len = 2;
fixhdr.rem_buf = (unsigned char *)malloc(fixhdr.rem_len);
fixhdr.rem_buf[0] = 0; // unused
fixhdr.rem_buf[1] = code;
mqtt_packet_encode(&fixhdr, buf, size);
}
//--------------------------------------------
void mqtt_pubxxx_encode(mqtt_msg_type_t msg_type, unsigned char **buf, size_t *size, uint16_t msg_id)
{
mqtt_fixed_header_t fixhdr;
fixhdr.msg_type = msg_type;
fixhdr.dup_flag = 0;
if (msg_type == MQTT_PUBREL)
fixhdr.qos_level = 1;
else
fixhdr.qos_level = 0;
fixhdr.retain = 0;
fixhdr.rem_len = 2;
fixhdr.rem_buf = (unsigned char *)malloc(fixhdr.rem_len);
*(uint16_t *)&fixhdr.rem_buf[0] = htons(msg_id);
mqtt_packet_encode(&fixhdr, buf, size);
}
//--------------------------------------------
void mqtt_publish_encode(unsigned char **buf, size_t *size, mqtt_publish_header_t *publish)
{
mqtt_fixed_header_t fixhdr;
uint16_t name_len = publish->pub_item->name_len;
uint16_t data_len = publish->pub_item->data_len;
uint8_t *name = publish->pub_item->name;
uint8_t *data = publish->pub_item->data;
uint16_t msg_id_len = publish->qos > 0 ? 2 : 0;
fixhdr.msg_type = MQTT_PUBLISH;
fixhdr.dup_flag = 0;
fixhdr.qos_level = publish->qos;
fixhdr.retain = 0;
fixhdr.rem_len = (uint32_t)(2 + name_len + msg_id_len + data_len);
fixhdr.rem_buf = (uint8_t *)malloc(fixhdr.rem_len);
*(uint16_t *)&fixhdr.rem_buf[0] = htons(name_len);
memcpy(&fixhdr.rem_buf[2], name, name_len);
if (fixhdr.qos_level > 0)
*(uint16_t *)&fixhdr.rem_buf[2 + name_len] = htons(publish->msg_id);
memcpy(&fixhdr.rem_buf[2 + name_len + msg_id_len], data, data_len);
mqtt_packet_encode(&fixhdr, buf, size);
}
