使用STM32 W5500做MQTT Client,使得數據上傳broker,並接收broker傳來的消息,並支持斷網/拔網線再插入網線能夠重新連接broker這樣的功能,需要具備以下條件:
1、STM32 W5500基礎入網配置,使能PC電腦端可以PING通W5500。
2、STM32 W5500的TCP Client收發數據的迴環測試沒有問題。
關於MQTT的介紹,本文不做重點。需要了解的是MQTT協議是基於TCP協議之上封裝的協議。
關於MQTT Client依賴的MQTT支持庫函數,下載地址 《MQTT C語言庫函數》
這些庫函數是幹嘛的?
MQTT協議在STM32 W5500中使用的前提,首先通過TCP連接到broker指定的IP和端口。
然後需要發送MQTT連接的指令,這個指令內容是通過 "MQTTConnectClient.c"文件中的
int MQTTSerialize_connect(unsigned char* buf, int buflen, MQTTPacket_connectData* options)
這個方法來實現組裝的,返回值大於0表示組裝後的數組有效內容長度,在通過W5500的send方法,發送給broker。
broker接收到Client端發來的MQTT連接請求後,會返回一組數據,判斷是否連接成功,或者各種失敗(協議版本錯誤,用戶名密碼錯誤等)。
MQTT Client如果想要接收到broker發來的消息,需要先訂閱主題,訂閱主題的指令內容是通過"MQTTSubscribeClient.c"文件中的
int MQTTSerialize_subscribe(unsigned char* buf, int buflen, unsigned char dup, unsigned short packetid, int count,
MQTTString topicFilters[], int requestedQoSs[])
這個方法來實現組裝的,同樣返回值大於0表示組裝後的數組有效內容長度,在通過W5500的send方法,發送給broker。
以上兩個舉例都是組裝指令內容。
那麼接收到broker發來消息,如何解析?
"MQTTDeserializePublish.c"這個文件的
int MQTTDeserialize_publish(unsigned char* dup, int* qos, unsigned char* retained, unsigned short* packetid, MQTTString* topicName,
unsigned char** payload, int* payloadlen, unsigned char* buf, int buflen)
這個方法可以實現消息內容的解析。
總之,依賴的MQTT支持庫函數幾乎可以使我們不用在乎協議的具體內容,就可以實現MQTT Client的功能。
STM32 W5500 MQTT Client端,我通過枚舉類型給它定義三種狀態
enum MQTT_STATE {MQTT_INIT, MQTT_CONNOK, MQTT_SUBOK};
MQTT_INIT - 初始狀態(MQTT未連接,未訂閱,注意是MQTT的,而不是TCP連接了沒有)
MQTT_CONNOK - MQTT連接成功(MQTT Client端發起MQTT連接,並接收到了broker返回連接成功)
MQTT_SUBOK - MQTT訂閱成功(MQTT Client端想broker訂閱消息,並受到了broker返回訂閱成功)
這幾種狀態的關連,在程序開始執行時,MQTT Client端處於MQTT_INIT狀態,或者程序執行一段時間後,MQTT PING指令發幾次broker沒有回覆,認爲MQTT Client端處於MQTT_INIT狀態。
MQTT Client端處於MQTT_CONNOK 狀態時可以發佈數據到broker,但是無法接收來自broker的消息。
MQTT Client端處於MQTT_SUBOK 狀態時可以發佈數據到broker,也可以接收來自broker的消息。
如果TCP Client處於CLOSE的狀態,那麼MQTT Client端將處於MQTT_INIT 狀態。
做好MQTT Client端的難點在於維繫 TCP socket的狀態與MQTT Client的狀態的關係。
貼出我實現MQTT Client的c代碼:
impl_mqtt.c
#ifndef __IMPL_MQTT_H
#define __IMPL_MQTT_H
#include "impl_mqtt.h"
#endif
int mqttstate = MQTT_INIT;
int cnt_ping_not_response = 0;
int cnt_sock_init = 0;
u8 buf_pub[1024];
u32 ping_timestamp, now_timestamp;
int func_tcp_sock_send(u8 sockno, u8 *buf_mqsend, u16 len_mqsend)
{
if(getSn_SR(sockno) == SOCK_ESTABLISHED)
{
return send(sockno, buf_mqsend, len_mqsend);
}
return -1;
}
int func_tcp_sock_read(u8 sockno, u8 *buf_mqrecv, u16 len_mqrecv)
{
if((getSn_SR(sockno) == SOCK_ESTABLISHED))
{
len_mqrecv = getSn_RX_RSR(sockno);
if(len_mqrecv > 0)
{
return recv(sockno, buf_mqrecv, len_mqrecv);
}
}
return -1;
}
void func_judge_timeout_ms(u32 *timespan)
{
delay_ms(1);
*timespan = *timespan + 1;
}
u8 func_judge_mqtt_recvmsg_package_type(u8 *buf_mqrecv, u16 len_mqrecv)
{
MQTTHeader header = {0};
if(len_mqrecv > 0)
{
header.byte = buf_mqrecv[0];
return header.bits.type;
}
return 0;
}
void func_mqtt_client_dealwith_recvmsg(u8 sockno, u8 *buf_mqrecv, u16 len_mqbuf, u16 len_mqrecv)
{
if(len_mqrecv > 0)
{
ping_timestamp = get_systick_timestamp();
// package type to deal
switch(func_judge_mqtt_recvmsg_package_type(buf_mqrecv, len_mqrecv))
{
case CONNACK:
break;
case PUBLISH://analysis msg
{
int rc;
u8 buf_recv[1024];
u8* payload;
int len_payload;
unsigned char retained, dup;
int qos;
unsigned short packetid;
MQTTString topicrecv;
MQTTString topicpub;
payload = buf_recv;
rc = MQTTDeserialize_publish(&dup, &qos, &retained, &packetid, &topicrecv, &payload, &len_payload, buf_mqrecv, len_mqrecv);
if(rc == 1)
{
//TODO ...
//TEST code
topicpub.cstring = (char*)"mytopic";
memset(buf_pub, 0, sizeof(buf_pub));
func_run_mqtt_publish(sockno, buf_pub, sizeof(buf_pub), topicpub, payload, len_payload);
}
}
break;
case PUBACK:
break;
case PUBREC://Qos2 msg receipt
case PUBREL://Qos2 msg receipt
case PUBCOMP://Qos2 msg receipt
{
unsigned char packettype, dup;
unsigned short packetid;
if (MQTTDeserialize_ack(&packettype, &dup, &packetid, buf_mqrecv, len_mqbuf) == 1)
{
memset(buf_mqrecv, 0, len_mqbuf);
len_mqrecv = MQTTSerialize_ack(buf_mqrecv, len_mqbuf, packettype, dup, packetid);
if(len_mqrecv > 0)
{
func_tcp_sock_send(sockno, buf_mqrecv, len_mqrecv);
}
}
}
break;
case SUBACK:
case UNSUBACK:
case PINGREQ:
case PINGRESP:
case DISCONNECT:
break;
default:
break;
}
}
}
void func_mqtt_client_connect_broker(int *state, u8 sockno, u8 *buf_mqsend, u16 len_mqsend, MQTTPacket_connectData *conn_mqtt)
{
u32 timespan;
int len_cont;
int res;
len_cont = MQTTSerialize_connect(buf_mqsend, len_mqsend, conn_mqtt);
if(len_cont > 0)
{
res = func_tcp_sock_send(sockno, buf_mqsend, len_cont);
if(res > 0)
{
timespan = 0;
memset(buf_mqsend, 0, len_mqsend);//reuse buffer
for(;;)
{
if((len_cont = func_tcp_sock_read(sockno, buf_mqsend, len_mqsend)) > 3)
{
if(func_judge_mqtt_recvmsg_package_type(buf_mqsend, len_cont) == CONNACK)
{
*state = MQTT_CONNOK;
ping_timestamp = get_systick_timestamp();
}
break;
}
func_judge_timeout_ms(×pan);
if(timespan > 500)
{
break;
}
}
}
}
}
void func_mqtt_client_ping_broker(int *state, u8 sockno, u8 *buf_mqsend, u16 len_mqsend)
{
u32 timespan;
int len_cont;
int res;
if(get_systick_timestamp() - ping_timestamp > 5*1000)
{
len_cont = MQTTSerialize_pingreq(buf_mqsend, len_mqsend);
if(len_cont > 0)
{
res = func_tcp_sock_send(sockno, buf_mqsend, len_cont);
if(res > 0)
{
timespan = 0;
memset(buf_mqsend, 0, len_mqsend);//reuse buffer
for(;;)
{
len_cont = func_tcp_sock_read(sockno, buf_mqsend, len_mqsend);
// pingrsp or others' published msg
if(len_cont > 0)
{
//recv pingrsp
ping_timestamp = get_systick_timestamp();
cnt_ping_not_response = 0;
// other type msg to deal with
func_mqtt_client_dealwith_recvmsg(sockno, buf_mqsend, len_mqsend, len_cont);
break;
}
func_judge_timeout_ms(×pan);
if(timespan > 10)
{
cnt_ping_not_response ++;
if(cnt_ping_not_response > 1)
{
*state = MQTT_INIT;
close(sockno);
cnt_ping_not_response = 0;
}
break;
}
}
}
else
{
cnt_ping_not_response ++;
if(cnt_ping_not_response > 2)
{
*state = MQTT_INIT;
close(sockno);
cnt_ping_not_response = 0;
}
}
}
}
}
int func_run_mqtt_publish(u8 sockno, u8 *buf_mqsend, u16 len_mqsend, MQTTString topicName, u8* payload, int payloadlen)
{
int len;
int rc;
if(mqttstate >= MQTT_CONNOK)
{
len = MQTTSerialize_publish(buf_mqsend, len_mqsend, 0, 0, 0, 0, topicName, payload, payloadlen);
if(len > 0)
{
memcpy(buf_pub, buf_mqsend, len);
rc = func_tcp_sock_send(sockno, buf_pub, len);
if(rc > 0)
{
ping_timestamp = get_systick_timestamp();
}
return rc;
}
}
return 0;
}
int func_mqtt_client_subtopic_from_broker(u8 sockno, u8 *buf_mqsend, u16 len_mqsend, int count,\
MQTTString topicFilters[], int requestedQoSs[])
{
u32 timespan;
int len_cont;
int res;
if(mqttstate != MQTT_SUBOK)
{
len_cont = MQTTSerialize_subscribe(buf_mqsend, len_mqsend, 0, SUBSCRIBE, count, topicFilters, requestedQoSs);
if(len_cont > 0)
{
res = func_tcp_sock_send(sockno, buf_mqsend, len_cont);
if(res > 0)
{
timespan = 0;
memset(buf_mqsend, 0, len_mqsend);//reuse buffer
for(;;)
{
if((len_cont = func_tcp_sock_read(sockno, buf_mqsend, len_mqsend)) > 0 && func_judge_mqtt_recvmsg_package_type(buf_mqsend, len_cont) == SUBACK)//nowtime, ignore other type msg
{
mqttstate = MQTT_SUBOK;
ping_timestamp = get_systick_timestamp();
return 0;
}
func_judge_timeout_ms(×pan);
if(timespan > 500)
{
return -2;
}
}
}
}
}
return -1;
}
void func_mqtt_client_recvmsg_from_broker(u8 sockno, u8 *buf_mqsend, u16 len_mqsend)
{
int len_cont;
memset(buf_mqsend, 0, len_mqsend);
len_cont = func_tcp_sock_read(sockno, buf_mqsend, len_mqsend);
if(len_cont > 0)
{
func_mqtt_client_dealwith_recvmsg(sockno, buf_mqsend, len_mqsend, len_cont);
}
}
u8 func_run_mqtt_tcpsock(u8 sockno, u8 *broker_ip, u16 broker_port, u8 *buf_mqsend, u16 len_mqsend, MQTTPacket_connectData *conn_mqtt)
{
static u16 any_port = 50000;
u8 res;
switch(getSn_SR(sockno))
{
case SOCK_CLOSED:
{
close(sockno);
socket(sockno, Sn_MR_TCP, any_port++, 0x00);
cnt_sock_init++;
if(cnt_sock_init > 30)
{
cnt_sock_init = 0;
close(sockno);
mqttstate = MQTT_INIT;
}
if(any_port > 64000)
{
any_port =50000;
}
}
break;
case SOCK_INIT:
{
res = connect(sockno, broker_ip, broker_port);
if(res)
{
//mqtt connect request
mqttstate = func_run_mqtt_progress(mqttstate, sockno, buf_mqsend, len_mqsend, conn_mqtt);
}
else
{
if(cnt_ping_not_response > 0)
{
mqttstate = MQTT_INIT;
}
}
}
break;
case SOCK_ESTABLISHED:
{
//run mqtt progress
mqttstate = func_run_mqtt_progress(mqttstate, sockno, buf_mqsend, len_mqsend, conn_mqtt);
}
break;
case SOCK_CLOSE_WAIT:
{
mqttstate = MQTT_INIT;
close(sockno);
}
break;
default:
break;
}
return mqttstate;
}
u8 func_run_mqtt_progress(int state, u8 sockno, u8 *buf_mqsend, u16 len_mqsend, MQTTPacket_connectData *conn_mqtt)
{
switch(state)
{
case MQTT_INIT:
{
func_mqtt_client_connect_broker(&state, sockno, buf_mqsend, len_mqsend, conn_mqtt);
}
break;
case MQTT_CONNOK:
{
func_mqtt_client_ping_broker(&state, sockno, buf_mqsend, len_mqsend);
if(state > MQTT_INIT)
{
// func_mqtt_client_subtopic_from_broker(&state, sockno, buf_mqsend, len_mqsend);
}
}
break;
case MQTT_SUBOK:
{
func_mqtt_client_ping_broker(&state, sockno, buf_mqsend, len_mqsend);
if(state != MQTT_INIT)
{
func_mqtt_client_recvmsg_from_broker(sockno, buf_mqsend, len_mqsend);
}
}
break;
default:
break;
}
return state;
}
可能不是十分完美,但是一般工程上使用應該問題不大,我也測試了好久。
測試的主函數,是做了MQTT的迴環測試,MQTT Client端連接到broker後,發起訂閱主題,並一次性訂閱多個主題,分別是字符串subtopic、subtopic2、subtopic3、subtopic4。當其他客戶端連接到broker後,向這四個主題發佈消息,STM32 W5500 MQTT Client端接收後,會向 mytopic發佈一條消息。
#ifndef __STM32F10X_H
#define __STM32F10X_H
#include "stm32f10x.h"
#endif
#ifndef __Z_UTIL_TIME_H
#define __Z_UTIL_TIME_H
#include "z_util_time.h"
#endif
#ifndef __Z_HARDWARE_LED_H
#define __Z_HARDWARE_LED_H
#include "z_hardware_led.h"
#endif
#ifndef __Z_HARDWARE_SPI_H
#define __Z_HARDWARE_SPI_H
#include "z_hardware_spi.h"
#endif
#ifndef __W5500_H
#define __W5500_H
#include "w5500.h"
#endif
#ifndef __SOCKET_H
#define __SOCKET_H
#include "socket.h"
#endif
#ifndef __W5500_CONF_H
#define __W5500_CONF_H
#include "w5500_conf.h"
#endif
#ifndef __DHCP_H
#define __DHCP_H
#include "dhcp.h"
#endif
#ifndef __Z_HARDWARE_USART2_H
#define __Z_HARDWARE_USART2_H
#include "z_hardware_usart2.h"
#endif
#include "MQTTPacket.h"
#ifndef __IMPL_MQTT_H
#define __IMPL_MQTT_H
#include "impl_mqtt.h"
#endif
int main(void)
{
u32 dhcp_timestamp;
u8 ip_broker[] = {192, 168, 1, 127};
u16 port_broker = 1883;
u8 buf_mqtt_send[1024];
u8 mac[6]={0, };
DHCP_Get dhcp_get;
int mqtt_stat;
MQTTString sub_topic = MQTTString_initializer;
MQTTString sub_topic2 = MQTTString_initializer;
MQTTString sub_topic3 = MQTTString_initializer;
MQTTString sub_topic4 = MQTTString_initializer;
MQTTString sub_topics[4];
int nums_sub_topic_qoss[4] = {0, };
char stpc_str[64] = {'t', 'c'};
MQTTPacket_connectData conn_mqtt = MQTTPacket_connectData_initializer;
conn_mqtt.willFlag = 0;
conn_mqtt.MQTTVersion = 3;
conn_mqtt.clientID.cstring = (char*)"dev_abcdef";
conn_mqtt.username.cstring = (char*)"abcdef";
conn_mqtt.password.cstring = (char*)"123456";
conn_mqtt.keepAliveInterval = 60;
conn_mqtt.cleansession = 1;
systick_configuration();
init_led();
init_system_spi();
func_w5500_reset();
init_hardware_usart2_dma(9600);
getMacByLockCode(mac);
setSHAR(mac);
sysinit(txsize, rxsize);
setRTR(2000);
setRCR(3);
//DHCP
for(;func_dhcp_get_ip_sub_gw(1, mac, &dhcp_get, 500) != 0;);
if(func_dhcp_get_ip_sub_gw(1, mac, &dhcp_get, 500) == 0)
{
setSUBR(dhcp_get.sub);
setGAR(dhcp_get.gw);
setSIPR(dhcp_get.lip);
close(1);
}
dhcp_timestamp = get_systick_timestamp();
memcpy(stpc_str, (char*)"subtopic", strlen("subtopic"));
sub_topic.cstring = stpc_str;
sub_topics[0] = sub_topic;
sub_topic2.cstring = "subtopic2";
sub_topics[1] = sub_topic2;
sub_topic3.cstring = "subtopic3";
sub_topics[2] = sub_topic3;
sub_topic4.cstring = "subtopic4";
sub_topics[3] = sub_topic4;
for(;;)
{
if(get_systick_timestamp() - dhcp_timestamp > 59*1000)// 1 min dhcp
{
dhcp_timestamp = get_systick_timestamp();
if(func_dhcp_get_ip_sub_gw(1, mac, &dhcp_get, 500) == 0)
{
setSUBR(dhcp_get.sub);
setGAR(dhcp_get.gw);
setSIPR(dhcp_get.lip);
close(1);
}
}
mqtt_stat = func_run_mqtt_tcpsock(2, ip_broker, port_broker, buf_mqtt_send, sizeof(buf_mqtt_send), &conn_mqtt);
if(mqtt_stat >= MQTT_CONNOK)
{
if(mqtt_stat == MQTT_CONNOK)
{
memset(buf_mqtt_send, 0, sizeof(buf_mqtt_send));
func_mqtt_client_subtopic_from_broker(2, buf_mqtt_send, sizeof(buf_mqtt_send), 4, sub_topics, nums_sub_topic_qoss);
}
func_led1_toggle();
}
delay_ms(500);
}
}
電腦端使用MQTT.fx工具進行測試,測試效果
目前測試還比較穩定,支持熱插拔網線,以及路由器斷網後再次聯網,MQTT Client仍可繼續連接broker。