底層包說明

1.MQTT文件夾

mqtt_msg 文件作為最底層的最直接的MQTT協議處理文件.

該文件可以單獨使用,該文件是我參考ESP8266的底層移植修改而來.拿去!

mqtt_msg.c

/**
  ******************************************************************************
  * @author  yang feng wu 
  * @version V1.0.0
  * @date    2019/12/15
  * @brief   
  ******************************************************************************
    
  ******************************************************************************
  */

#define MQTTCLIENT_C_//如果沒有定義

#include "mqtt_msg.h"
#include "string.h"
#include "stm32f10x.h"


#define MQTT_MAX_FIXED_HEADER_SIZE 3

uint16_t mqtt_message_id = 0;

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
};
//__attribute((__packed__))
struct  mqtt_connect_variable_header
{
  uint8_t lengthMsb;
  uint8_t lengthLsb;
  uint8_t magic[4];
  uint8_t version;
  uint8_t flags;
  uint8_t keepaliveMsb;
  uint8_t keepaliveLsb;
};


int mqtt_get_type(unsigned char* buffer) { return (buffer[0] & 0xf0) >> 4; }
int mqtt_get_connect_ret_code(unsigned char* buffer) { return (buffer[3]); }
int mqtt_get_qos(unsigned char* buffer) { return (buffer[0] & 0x06) >> 1; }


int append_string(int *length,unsigned  char* buffer,int buffer_length,unsigned  char* string, int len)
{
  if((*length) + len + 2 > buffer_length)//加上 ClientID 和 記錄 ClientID個數(兩位) 以后超出了數組
    return -1;

  buffer[(*length)++] = len >> 8;
  buffer[(*length)++] = len & 0xff;
  c_memcpy(buffer + (*length), string, len);
  (*length) += len;
  return len + 2;
}



uint16_t append_message_id(int *length,unsigned  char* buffer,int buffer_length, 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 = ++mqtt_message_id;

  if((*length) + 2 > buffer_length)
    return 0;

  buffer[(*length)++] = message_id >> 8;
  buffer[(*length)++] = message_id & 0xff;
    
  return message_id;
}


int fini_message(unsigned char **data_ptr,int    length,unsigned char* buffer, int type, int dup, int qos, int retain)
{
  int remaining_length = length - MQTT_MAX_FIXED_HEADER_SIZE;
    
  if(remaining_length > 127)
  {
    buffer[0] = ((type & 0x0f) << 4) | ((dup & 1) << 3) | ((qos & 3) << 1) | (retain & 1);
    buffer[1] = 0x80 | (remaining_length % 128);
    buffer[2] = remaining_length / 128;
    length = remaining_length + 3;
    *data_ptr = buffer;
  }
  else
  {
    buffer[1] = ((type & 0x0f) << 4) | ((dup & 1) << 3) | ((qos & 3) << 1) | (retain & 1);
    buffer[2] = remaining_length;
    length = remaining_length + 2;
    *data_ptr = buffer + 1;
  }

  return length;
}



uint16_t mqtt_get_id(unsigned char* buffer, uint16_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:
    {
      // 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;
  }
}



/**
* @brief   獲取MQTT返回的數據長度(去掉1和2字節后面數據的長度)
* @param   buffer   MQTT返回的數據首地址
* @param   length   返回的數據個數
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_get_total_length(unsigned char* buffer, uint16_t length)
{
  int i;
  int totlen = 0;

  for(i = 1; i < length; ++i)
  {
    totlen += (buffer[i] & 0x7f) << (7 * (i - 1));
    if((buffer[i] & 0x80) == 0)
    {
      ++i;
      break;
    }
  }
  totlen += i;

  return totlen;
}




/**
* @brief   打包連接MQTT指令
* @param   info     MQTT信息
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_connect(mqtt_connect_info_t* info,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
  struct mqtt_connect_variable_header* variable_header;
    
    mqtt_message_id = 0;
    
    length = MQTT_MAX_FIXED_HEADER_SIZE;//頭.連接類型1位,數據個數2位(如果大於127就需要兩位)
    
  if(length + sizeof(*variable_header) > buffer_length)//數組不夠存儲的
    return 0;
    
  variable_header = (void*)(buffer + length);//把數組分給這個結構體里面的變量
  length += sizeof(*variable_header);//存儲完 連接類型,整個數據個數,版本號個數,版本號,等
    
  variable_header->lengthMsb = 0;//版本名稱個數高位
  variable_header->lengthLsb = 4;//版本名稱個數低位
  c_memcpy(variable_header->magic, "MQTT", 4);//版本名稱MQTT
  variable_header->version = 4;//版本號
  variable_header->flags = 0;//先清零
  variable_header->keepaliveMsb = info->keepalive >> 8;//心跳包時間
  variable_header->keepaliveLsb = info->keepalive & 0xff;//心跳包時間

  if(info->clean_session)//清除連接信息
    variable_header->flags |= MQTT_CONNECT_FLAG_CLEAN_SESSION;

  if(info->client_id != NULL && info->client_id[0] != '\0')//client_id
  {
    if(append_string(&length,buffer,buffer_length, info->client_id, c_strlen(info->client_id)) < 0)//拷貝
      return -1;//數組不夠用呀...
  }
  else
    return -2;//沒有設置client_id

  if(info->will_topic != NULL && info->will_topic[0] != '\0')//遺囑
  {
    if(append_string(&length,buffer,buffer_length , info->will_topic, c_strlen(info->will_topic)) < 0)//遺囑的主題
      return -3;

    if(append_string(&length,buffer,buffer_length , info->will_message, c_strlen(info->will_message)) < 0)//遺囑的消息
      return -4;

    variable_header->flags |= MQTT_CONNECT_FLAG_WILL;//需要遺囑
    if(info->will_retain)//遺囑是夠需要服務器保留
      variable_header->flags |= MQTT_CONNECT_FLAG_WILL_RETAIN;//保留遺囑
    variable_header->flags |= (info->will_qos & 3) << 3;//遺囑消息等級
  }
    
  if(info->username != NULL && info->username[0] != '\0')//username
  {
    if(append_string(&length,buffer,buffer_length, info->username, c_strlen(info->username)) < 0)//拷貝用戶名
      return -5;

    variable_header->flags |= MQTT_CONNECT_FLAG_USERNAME;//有用戶名
  }
    
  if(info->password != NULL && info->password[0] != '\0')//password
  {
    if(append_string(&length,buffer,buffer_length, info->password, c_strlen(info->password)) < 0)
      return -6;

    variable_header->flags |= MQTT_CONNECT_FLAG_PASSWORD;//有密碼
  }

  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_CONNECT, 0, 0, 0);//最終組合連接MQTT的指令
}


/**
* @brief  判斷是否連接上MQTT
* @param  服務器返回的數據
* @param  
* @retval 0 連接成功
* @example 
**/
int  mqtt_msg_connect_ack(unsigned char *buff)
{
    if(mqtt_get_type(buff) == MQTT_MSG_TYPE_CONNACK)
    {
        return mqtt_get_connect_ret_code(buff);
    }
    return -1;
}


/**
* @brief   斷開連接
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_disconnect(unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
    length = MQTT_MAX_FIXED_HEADER_SIZE;
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_DISCONNECT, 0, 0, 0);
}



/**
* @brief   訂閱主題
* @param   topic   訂閱的主題
* @param   qos     消息等級
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_subscribe_topic(unsigned char* topic, int qos,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
    length = MQTT_MAX_FIXED_HEADER_SIZE;
    
    if(topic == NULL || topic[0] == '\0')
        return -1;
    
    if((mqtt_message_id = append_message_id(&length, buffer, buffer_length, 0)) == 0)
        return -2;
    
    if(append_string(&length, buffer, buffer_length, topic, c_strlen(topic)) < 0)
        return -3;
    
    if(length + 1 > buffer_length)
    return -4;
  buffer[length++] = qos;
    
    return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_SUBSCRIBE, 0, 1, 0);
}



/**
* @brief  判斷是否成功訂閱
* @param  buffer  服務器返回的數據
* @param  length  服務器返回的數據長度
* @retval 0:成功  1:失敗
* @example 
**/
int mqtt_msg_subscribe_ack(unsigned char* buffer, uint16_t length)
{
    if(mqtt_get_type(buffer) == MQTT_MSG_TYPE_SUBACK)
    {
        if(mqtt_get_id(buffer,length) == mqtt_message_id)
        {
            return 0;
        }
        else
        {
            return 1;
        }
    }
    else
    {
        return 1;
    }
}


/**
* @brief   發布消息
* @param   topic    主題
* @param   data     消息
* @param   data_length 消息長度
* @param   qos      消息等級
* @param   retain   是否需要保留消息
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_publish(unsigned char* topic,unsigned  char* date, int data_length, int qos, int retain,unsigned  char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
    length = MQTT_MAX_FIXED_HEADER_SIZE;

  if(topic == NULL || topic[0] == '\0')
    return -1;

  if(append_string(&length, buffer, buffer_length, topic, strlen(topic)) < 0)
    return -2;

  if(qos > 0)
  {
    if((mqtt_message_id = append_message_id(&length, buffer, buffer_length,  0)) == 0)
      return -3;
  }
  else
    mqtt_message_id = 0;

  if(length + data_length > buffer_length)
    return -4;
  memcpy(buffer + length, date, data_length);
  length += data_length;

  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PUBLISH, 0, qos, retain);
}



int mqtt_msg_puback(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
  length = MQTT_MAX_FIXED_HEADER_SIZE;
  if(append_message_id(&length, buffer, buffer_length,message_id) == 0)
    return -1;
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PUBACK, 0, 0, 0);
}


int mqtt_msg_pubrec(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
  length = MQTT_MAX_FIXED_HEADER_SIZE;
  if(append_message_id(&length, buffer, buffer_length,message_id) == 0)
    return -1;
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PUBREC, 0, 0, 0);
}


int mqtt_msg_pubrel(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
  length = MQTT_MAX_FIXED_HEADER_SIZE;
    
  if(append_message_id(&length, buffer, buffer_length,message_id) == 0)
    return -1;
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PUBREL, 0, 1, 0);
}


int mqtt_msg_pubcomp(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
  length = MQTT_MAX_FIXED_HEADER_SIZE;
  if(append_message_id(&length, buffer, buffer_length,message_id) == 0)
    return -1;
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PUBCOMP, 0, 0, 0);
}


const char* mqtt_get_publish_topic(unsigned char* buffer, uint16_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 (const char*)(buffer + i);
}


const char* mqtt_get_publish_data(unsigned char* buffer, uint16_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 (const char*)(buffer + i);
}

/**
* @brief   打包服務器返回的心跳包數據(用不到)
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_pingresp(unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
    length = MQTT_MAX_FIXED_HEADER_SIZE;    
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PINGRESP, 0, 0, 0);
}

/**
* @brief   獲取發送給服務器的心跳包數據
* @param   data_ptr 打包的數據首地址
* @param   buffer   打包進的數組
* @param   buffer_length 數組長度
* @retval  數據長度 
* @warning None
* @example 
**/
int mqtt_msg_pingreq(unsigned char **data_ptr,unsigned char* buffer,int buffer_length)
{
    int length;
    length = MQTT_MAX_FIXED_HEADER_SIZE;    
  return fini_message(data_ptr,length, buffer, MQTT_MSG_TYPE_PINGREQ, 0, 0, 0);
}

View Code

mqtt_msg.h

#ifndef MQTTCLIENT_H_
#define MQTTCLIENT_H_


#ifndef MQTTCLIENT_C_//如果沒有定義
#define MQTTCLIENT_Cx_ extern
#else
#define MQTTCLIENT_Cx_
#endif

#include "string.h"
#include "stm32f10x.h"

#define c_memcpy memcpy
#define c_memset memset
#define c_strlen strlen


enum mqtt_message_type
{
  MQTT_MSG_TYPE_CONNECT = 1,
  MQTT_MSG_TYPE_CONNACK = 2,
  MQTT_MSG_TYPE_PUBLISH = 3,
  MQTT_MSG_TYPE_PUBACK = 4,
  MQTT_MSG_TYPE_PUBREC = 5,
  MQTT_MSG_TYPE_PUBREL = 6,
  MQTT_MSG_TYPE_PUBCOMP = 7,
  MQTT_MSG_TYPE_SUBSCRIBE = 8,
  MQTT_MSG_TYPE_SUBACK = 9,
  MQTT_MSG_TYPE_UNSUBSCRIBE = 10,
  MQTT_MSG_TYPE_UNSUBACK = 11,
  MQTT_MSG_TYPE_PINGREQ = 12,
  MQTT_MSG_TYPE_PINGRESP = 13,
  MQTT_MSG_TYPE_DISCONNECT = 14
};

enum mqtt_connack_return_code
{
    MQTT_CONN_FAIL_SERVER_NOT_FOUND = -5,
    MQTT_CONN_FAIL_NOT_A_CONNACK_MSG = -4,
    MQTT_CONN_FAIL_DNS = -3,
    MQTT_CONN_FAIL_TIMEOUT_RECEIVING = -2,
    MQTT_CONN_FAIL_TIMEOUT_SENDING = -1,
    MQTT_CONNACK_ACCEPTED = 0,
    MQTT_CONNACK_REFUSED_PROTOCOL_VER = 1,
    MQTT_CONNACK_REFUSED_ID_REJECTED = 2,
    MQTT_CONNACK_REFUSED_SERVER_UNAVAILABLE = 3,
    MQTT_CONNACK_REFUSED_BAD_USER_OR_PASS = 4,
    MQTT_CONNACK_REFUSED_NOT_AUTHORIZED = 5
};



//連接MQTT指令 
typedef struct mqtt_connect_info
{
  unsigned  char* client_id;
  unsigned  char* username;
  unsigned  char* password;
  unsigned  char* will_topic;
  unsigned  char* will_message;
  int keepalive;
  int will_qos;
  int will_retain;
  int clean_session;
    
} mqtt_connect_info_t;


int mqtt_get_type(unsigned char* buffer);
int mqtt_get_connect_ret_code(unsigned char* buffer);
int mqtt_get_qos(unsigned char* buffer);
uint16_t mqtt_get_id(unsigned char* buffer, uint16_t length);

int mqtt_msg_connect(mqtt_connect_info_t* info,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);
int mqtt_msg_connect_ack(unsigned char *buff);
int mqtt_msg_subscribe_topic(unsigned char* topic, int qos,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);
int mqtt_msg_subscribe_ack(unsigned char* buffer, uint16_t length);
int mqtt_msg_publish(unsigned char* topic,unsigned char* date, int data_length, int qos, int retain,unsigned  char **data_ptr,unsigned char* buffer,int buffer_length);

int mqtt_get_total_length(unsigned char* buffer, uint16_t length);

int mqtt_msg_puback(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);
int mqtt_msg_pubrel(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);
int mqtt_msg_pubrec(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);
int mqtt_msg_pubcomp(uint16_t message_id,unsigned char **data_ptr,unsigned char* buffer,int buffer_length);

const char* mqtt_get_publish_topic(unsigned char* buffer, uint16_t* length);
const char* mqtt_get_publish_data(unsigned char* buffer, uint16_t* length);

int mqtt_msg_pingreq(unsigned char **data_ptr,unsigned char* buffer,int buffer_length);

#endif