MQTT数据包生成代码

#include "mqtt.h" unsigned char GetDataFixedHead(unsigned char MesType,unsigned char DupFlag,unsigned char QosLevel,unsigned char Retain) { unsigned char dat = 0; dat = (MesType & 0x0f) << 4; dat |= (DupFlag & 0x01) << 3; dat |= (QosLevel & 0x03) << 1; dat |= (Retain & 0x01); return dat; } void GetDataConnet(unsigned char *buff)//获取连接的数据包正确连接返回20 02 00 00 { unsigned int i,len,lennum = 0; unsigned char *msg; buff[0] = GetDataFixedHead(MQTT_TypeCONNECT,0,0,0); buff[2] = 0x00; buff[3] = 0x04; buff[4] = 'M'; buff[5] = 'Q'; buff[6] = 'T'; buff[7] = 'T'; buff[8] = 0x04;//协议级别 Protocol Level buff[9] = 0 | (MQTT_StaCleanSession << 1) | (MQTT_StaWillFlag << 1) | (MQTT_StaWillQoS << 3) | (MQTT_StaWillRetain << 5) | (MQTT_StaPasswordFlag << 6) |(MQTT_StaUserNameFlag << 7);//连接标志 buff[10] = MQTT_KeepAlive >> 8; buff[11] = MQTT_KeepAlive; len = strlen(MQTT_ClientIdentifier); buff[12] = len >> 8; buff[13] = len; msg = MQTT_ClientIdentifier; for(i = 0;i<len;i++) { buff[14+i] = msg[i]; } lennum += len; if(MQTT_StaWillFlag) { len = strlen(MQTT_WillTopic); buff[13 + lennum + 1] = len >> 8; buff[13 + lennum + 2] = len; lennum += 2; msg = MQTT_WillTopic; for(i = 0;i<len;i++) { buff[14+lennum+i] = msg[i]; } lennum += len; len = strlen(MQTT_WillMessage); buff[12] = len >> 8; buff[13] = len; lennum += 2; msg = MQTT_WillMessage; for(i = 0;i<len;i++) { buff[14+lennum+i] = msg[i]; } lennum += len; } if(MQTT_StaUserNameFlag) { len = strlen(MQTT_UserName); buff[13 + lennum + 1] = len >> 8; buff[13 + lennum + 2] = len; lennum += 2; msg = MQTT_UserName; for(i = 0;i<len;i++) { buff[14+lennum+i] = msg[i]; } lennum += len; } if(MQTT_StaPasswordFlag) { len = strlen(MQTT_Password); buff[13 + lennum + 1] = len >> 8; buff[13 + lennum + 2] = len; lennum += 2; msg = MQTT_Password; for(i = 0;i<len;i++) { buff[14+lennum+i] = msg[i]; } lennum += len; } buff[1] = 13 + lennum - 1; } void GetDataDisConnet(unsigned char *buff)//获取断开连接的数据包 { buff[0] = 0xe0; buff[1] = 0; } void GetDataPINGREQ(unsigned char *buff)//心跳请求的数据包成功返回d0 00 { buff[0] = 0xc0; buff[1] = 0; } /* 成功返回90 0x 00 Num RequestedQoS */ void GetDataSUBSCRIBE(unsigned char *buff,const char *dat,unsigned int Num,unsigned char RequestedQoS)//订阅主题的数据包 Num:主题序号 RequestedQoS:服务质量要求0,1或2 { unsigned int i,len = 0,lennum = 0; buff[0] = 0x82; len = strlen(dat); buff[2] = Num>>8; buff[3] = Num; buff[4] = len>>8; buff[5] = len; for(i = 0;i<len;i++) { buff[6+i] = dat[i]; } lennum = len; buff[6 + lennum ] = RequestedQoS; buff[1] = lennum + 5; } void GetDataPUBLISH(unsigned char *buff,unsigned char dup, unsigned char qos,unsigned char retain,const char *topic ,const char *msg)//获取发布消息的数据包 { unsigned int i,len=0,lennum=0; buff[0] = GetDataFixedHead(MQTT_TypePUBLISH,dup,qos,retain); len = strlen(topic); buff[2] = len>>8; buff[3] = len; for(i = 0;i<len;i++) { buff[4+i] = topic[i]; } lennum = len; len = strlen(msg); for(i = 0;i<len;i++) { buff[4+i+lennum] = msg[i]; } lennum += len; buff[1] = lennum + 2; }