503 lines
14 KiB
C
503 lines
14 KiB
C
/*
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* Copyright (c) 2014, Stephen Robinson
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the copyright holder nor the names of its
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* contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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*/
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#include "c_string.h"
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#include "mqtt_msg.h"
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#define MQTT_MAX_FIXED_HEADER_SIZE 3
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enum mqtt_connect_flag
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{
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MQTT_CONNECT_FLAG_USERNAME = 1 << 7,
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MQTT_CONNECT_FLAG_PASSWORD = 1 << 6,
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MQTT_CONNECT_FLAG_WILL_RETAIN = 1 << 5,
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MQTT_CONNECT_FLAG_WILL = 1 << 2,
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MQTT_CONNECT_FLAG_CLEAN_SESSION = 1 << 1
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};
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struct __attribute((__packed__)) mqtt_connect_variable_header
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{
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uint8_t lengthMsb;
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uint8_t lengthLsb;
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uint8_t magic[4];
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uint8_t version;
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uint8_t flags;
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uint8_t keepaliveMsb;
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uint8_t keepaliveLsb;
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};
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static int append_string(mqtt_connection_t* connection, const char* string, int len)
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{
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if(connection->message.length + len + 2 > connection->buffer_length)
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return -1;
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connection->buffer[connection->message.length++] = len >> 8;
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connection->buffer[connection->message.length++] = len & 0xff;
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c_memcpy(connection->buffer + connection->message.length, string, len);
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connection->message.length += len;
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return len + 2;
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}
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static uint16_t append_message_id(mqtt_connection_t* connection, uint16_t message_id)
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{
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// If message_id is zero then we should assign one, otherwise
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// we'll use the one supplied by the caller
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while(message_id == 0)
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message_id = ++connection->message_id;
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if(connection->message.length + 2 > connection->buffer_length)
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return 0;
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connection->buffer[connection->message.length++] = message_id >> 8;
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connection->buffer[connection->message.length++] = message_id & 0xff;
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return message_id;
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}
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static int init_message(mqtt_connection_t* connection)
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{
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connection->message.length = MQTT_MAX_FIXED_HEADER_SIZE;
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return MQTT_MAX_FIXED_HEADER_SIZE;
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}
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static mqtt_message_t* fail_message(mqtt_connection_t* connection)
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{
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connection->message.data = connection->buffer;
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connection->message.length = 0;
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return &connection->message;
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}
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static mqtt_message_t* fini_message(mqtt_connection_t* connection, int type, int dup, int qos, int retain)
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{
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int remaining_length = connection->message.length - MQTT_MAX_FIXED_HEADER_SIZE;
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if(remaining_length > 127)
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{
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connection->buffer[0] = ((type & 0x0f) << 4) | ((dup & 1) << 3) | ((qos & 3) << 1) | (retain & 1);
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connection->buffer[1] = 0x80 | (remaining_length % 128);
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connection->buffer[2] = remaining_length / 128;
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connection->message.length = remaining_length + 3;
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connection->message.data = connection->buffer;
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}
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else
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{
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connection->buffer[1] = ((type & 0x0f) << 4) | ((dup & 1) << 3) | ((qos & 3) << 1) | (retain & 1);
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connection->buffer[2] = remaining_length;
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connection->message.length = remaining_length + 2;
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connection->message.data = connection->buffer + 1;
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}
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return &connection->message;
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}
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void mqtt_msg_init(mqtt_connection_t* connection, uint8_t* buffer, uint16_t buffer_length)
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{
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c_memset(connection, 0, sizeof(connection));
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connection->buffer = buffer;
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connection->buffer_length = buffer_length;
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}
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int mqtt_get_total_length(uint8_t* buffer, uint16_t length)
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{
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int i;
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int totlen = 0;
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for(i = 1; i < length; ++i)
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{
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totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
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if((buffer[i] & 0x80) == 0)
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{
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++i;
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break;
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}
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}
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totlen += i;
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return totlen;
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}
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const char* mqtt_get_publish_topic(uint8_t* buffer, uint16_t* length)
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{
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int i;
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int totlen = 0;
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int topiclen;
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for(i = 1; i < *length; ++i)
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{
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totlen += (buffer[i] & 0x7f) << (7 * (i -1));
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if((buffer[i] & 0x80) == 0)
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{
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++i;
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break;
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}
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}
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totlen += i;
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if(i + 2 >= *length)
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return NULL;
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topiclen = buffer[i++] << 8;
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topiclen |= buffer[i++];
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if(i + topiclen > *length)
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return NULL;
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*length = topiclen;
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return (const char*)(buffer + i);
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}
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const char* mqtt_get_publish_data(uint8_t* buffer, uint16_t* length)
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{
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int i;
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int totlen = 0;
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int topiclen;
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for(i = 1; i < *length; ++i)
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{
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totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
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if((buffer[i] & 0x80) == 0)
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{
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++i;
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break;
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}
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}
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totlen += i;
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if(i + 2 >= *length)
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return NULL;
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topiclen = buffer[i++] << 8;
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topiclen |= buffer[i++];
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if(i + topiclen >= *length){
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*length = 0;
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return NULL;
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}
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i += topiclen;
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if(mqtt_get_qos(buffer) > 0)
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{
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if(i + 2 >= *length)
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return NULL;
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i += 2;
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}
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if(totlen < i)
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return NULL;
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if(totlen <= *length)
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*length = totlen - i;
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else
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*length = *length - i;
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return (const char*)(buffer + i);
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}
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uint16_t mqtt_get_id(uint8_t* buffer, uint16_t length)
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{
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if(length < 1)
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return 0;
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switch(mqtt_get_type(buffer))
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{
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case MQTT_MSG_TYPE_PUBLISH:
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{
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int i;
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int topiclen;
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for(i = 1; i < length; ++i)
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{
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if((buffer[i] & 0x80) == 0)
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{
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++i;
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break;
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}
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}
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if(i + 2 >= length)
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return 0;
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topiclen = buffer[i++] << 8;
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topiclen |= buffer[i++];
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if(i + topiclen >= length)
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return 0;
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i += topiclen;
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if(mqtt_get_qos(buffer) > 0)
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{
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if(i + 2 >= length)
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return 0;
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//i += 2;
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} else {
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return 0;
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}
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return (buffer[i] << 8) | buffer[i + 1];
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}
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case MQTT_MSG_TYPE_PUBACK:
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case MQTT_MSG_TYPE_PUBREC:
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case MQTT_MSG_TYPE_PUBREL:
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case MQTT_MSG_TYPE_PUBCOMP:
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case MQTT_MSG_TYPE_SUBACK:
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case MQTT_MSG_TYPE_UNSUBACK:
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case MQTT_MSG_TYPE_SUBSCRIBE:
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{
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// This requires the remaining length to be encoded in 1 byte,
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// which it should be.
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if(length >= 4 && (buffer[1] & 0x80) == 0)
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return (buffer[2] << 8) | buffer[3];
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else
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return 0;
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}
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default:
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return 0;
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}
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}
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mqtt_message_t* mqtt_msg_connect(mqtt_connection_t* connection, mqtt_connect_info_t* info)
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{
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struct mqtt_connect_variable_header* variable_header;
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init_message(connection);
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if(connection->message.length + sizeof(*variable_header) > connection->buffer_length)
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return fail_message(connection);
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variable_header = (void*)(connection->buffer + connection->message.length);
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connection->message.length += sizeof(*variable_header);
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variable_header->lengthMsb = 0;
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variable_header->lengthLsb = 4;
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c_memcpy(variable_header->magic, "MQTT", 4);
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variable_header->version = 4;
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variable_header->flags = 0;
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variable_header->keepaliveMsb = info->keepalive >> 8;
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variable_header->keepaliveLsb = info->keepalive & 0xff;
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if(info->clean_session)
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variable_header->flags |= MQTT_CONNECT_FLAG_CLEAN_SESSION;
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if(info->client_id != NULL && info->client_id[0] != '\0')
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{
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if(append_string(connection, info->client_id, c_strlen(info->client_id)) < 0)
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return fail_message(connection);
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}
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else
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return fail_message(connection);
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if(info->will_topic != NULL && info->will_topic[0] != '\0')
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{
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if(append_string(connection, info->will_topic, c_strlen(info->will_topic)) < 0)
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return fail_message(connection);
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if(append_string(connection, info->will_message, c_strlen(info->will_message)) < 0)
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return fail_message(connection);
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variable_header->flags |= MQTT_CONNECT_FLAG_WILL;
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if(info->will_retain)
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variable_header->flags |= MQTT_CONNECT_FLAG_WILL_RETAIN;
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variable_header->flags |= (info->will_qos & 3) << 3;
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}
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if(info->username != NULL && info->username[0] != '\0')
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{
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if(append_string(connection, info->username, c_strlen(info->username)) < 0)
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return fail_message(connection);
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variable_header->flags |= MQTT_CONNECT_FLAG_USERNAME;
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}
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if(info->password != NULL && info->password[0] != '\0')
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{
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if(append_string(connection, info->password, c_strlen(info->password)) < 0)
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return fail_message(connection);
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variable_header->flags |= MQTT_CONNECT_FLAG_PASSWORD;
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}
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return fini_message(connection, MQTT_MSG_TYPE_CONNECT, 0, 0, 0);
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}
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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)
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{
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init_message(connection);
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if(topic == NULL || topic[0] == '\0')
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return fail_message(connection);
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if(append_string(connection, topic, c_strlen(topic)) < 0)
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return fail_message(connection);
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if(qos > 0)
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{
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if((*message_id = append_message_id(connection, 0)) == 0)
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return fail_message(connection);
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}
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else
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*message_id = 0;
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if(connection->message.length + data_length > connection->buffer_length)
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return fail_message(connection);
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c_memcpy(connection->buffer + connection->message.length, data, data_length);
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connection->message.length += data_length;
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return fini_message(connection, MQTT_MSG_TYPE_PUBLISH, 0, qos, retain);
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}
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mqtt_message_t* mqtt_msg_puback(mqtt_connection_t* connection, uint16_t message_id)
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{
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init_message(connection);
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if(append_message_id(connection, message_id) == 0)
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return fail_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PUBACK, 0, 0, 0);
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}
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mqtt_message_t* mqtt_msg_pubrec(mqtt_connection_t* connection, uint16_t message_id)
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{
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init_message(connection);
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if(append_message_id(connection, message_id) == 0)
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return fail_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PUBREC, 0, 0, 0);
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}
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mqtt_message_t* mqtt_msg_pubrel(mqtt_connection_t* connection, uint16_t message_id)
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{
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init_message(connection);
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if(append_message_id(connection, message_id) == 0)
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return fail_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PUBREL, 0, 1, 0);
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}
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mqtt_message_t* mqtt_msg_pubcomp(mqtt_connection_t* connection, uint16_t message_id)
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{
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init_message(connection);
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if(append_message_id(connection, message_id) == 0)
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return fail_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PUBCOMP, 0, 0, 0);
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}
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mqtt_message_t* mqtt_msg_subscribe_init(mqtt_connection_t* connection, uint16_t *message_id)
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{
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init_message(connection);
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if((*message_id = append_message_id(connection, 0)) == 0)
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return fail_message(connection);
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return &connection->message;
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}
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mqtt_message_t* mqtt_msg_subscribe_topic(mqtt_connection_t* connection, const char* topic, int qos)
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{
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if(topic == NULL || topic[0] == '\0')
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return fail_message(connection);
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if(append_string(connection, topic, c_strlen(topic)) < 0)
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return fail_message(connection);
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if(connection->message.length + 1 > connection->buffer_length)
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return fail_message(connection);
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connection->buffer[connection->message.length++] = qos;
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return &connection->message;
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}
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mqtt_message_t* mqtt_msg_subscribe_fini(mqtt_connection_t* connection)
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{
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return fini_message(connection, MQTT_MSG_TYPE_SUBSCRIBE, 0, 1, 0);
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}
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mqtt_message_t* mqtt_msg_subscribe(mqtt_connection_t* connection, const char* topic, int qos, uint16_t* message_id)
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{
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mqtt_message_t* result;
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result = mqtt_msg_subscribe_init(connection, message_id);
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if (result->length != 0) {
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result = mqtt_msg_subscribe_topic(connection, topic, qos);
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}
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if (result->length != 0) {
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result = mqtt_msg_subscribe_fini(connection);
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}
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return result;
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}
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mqtt_message_t* mqtt_msg_unsubscribe_init(mqtt_connection_t* connection, uint16_t *message_id)
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{
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return mqtt_msg_subscribe_init(connection, message_id);
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}
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mqtt_message_t* mqtt_msg_unsubscribe_topic(mqtt_connection_t* connection, const char* topic)
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{
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if(topic == NULL || topic[0] == '\0')
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return fail_message(connection);
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if(append_string(connection, topic, c_strlen(topic)) < 0)
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return fail_message(connection);
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return &connection->message;
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}
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mqtt_message_t* mqtt_msg_unsubscribe_fini(mqtt_connection_t* connection)
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{
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return fini_message(connection, MQTT_MSG_TYPE_UNSUBSCRIBE, 0, 1, 0);
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}
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mqtt_message_t* mqtt_msg_unsubscribe(mqtt_connection_t* connection, const char* topic, uint16_t* message_id)
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{
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mqtt_message_t* result;
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result = mqtt_msg_unsubscribe_init(connection, message_id);
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if (result->length != 0) {
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result = mqtt_msg_unsubscribe_topic(connection, topic);
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}
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if (result->length != 0) {
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result = mqtt_msg_unsubscribe_fini(connection);
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}
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return result;
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}
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mqtt_message_t* mqtt_msg_pingreq(mqtt_connection_t* connection)
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{
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init_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PINGREQ, 0, 0, 0);
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}
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mqtt_message_t* mqtt_msg_pingresp(mqtt_connection_t* connection)
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{
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init_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_PINGRESP, 0, 0, 0);
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}
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mqtt_message_t* mqtt_msg_disconnect(mqtt_connection_t* connection)
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{
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init_message(connection);
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return fini_message(connection, MQTT_MSG_TYPE_DISCONNECT, 0, 0, 0);
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}
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