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Page 11 of 11

Chapter 10

Page 203 MQTT main program

#include <stdio.h>

#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"
#include "lwip/ip_addr.h"
#include "setupWifi.h"
#include "lwip/altcp.h"
#include "lwip/altcp_tls.h"
#include "lwip/apps/mqtt.h"

int mqttStatus = 0;

void mqtt_connection_cb(mqtt_client_t *client, void *arg, mqtt_connection_status_t status)
{
    if (status == MQTT_CONNECT_ACCEPTED)
    {
        mqttStatus = 1;
    }
}

static void pub_request_cb(void *arg, err_t result)
{
    printf("Publish result: %d\n", result);
    mqtt_client_t *client = (mqtt_client_t *)arg;
}

void sub_request_cb(void *arg, err_t result)
{
    printf("Subscribe result: %d\n", result);
    mqttStatus = 2;
}

static void incoming_publish_cb(void *arg, const char *topic, u32_t tot_len)
{
    printf("Topic %s. %d\n", topic, tot_len);
}

static void incoming_data_cb(void *arg, const u8_t *data, u16_t len, u8_t flags)
{
    char *payload = (char *)data;
    printf("payload\n%.*s\n", len, payload);
}

int main()
{
    stdio_init_all();
    connect();

    struct altcp_tls_config *tls_config = altcp_tls_create_config_client(NULL, 0);

    mqtt_client_t *client = mqtt_client_new();

    struct mqtt_connect_client_info_t ci;
    memset(&ci, 0, sizeof(ci));
    ci.client_id = "MyPicoW";
    ci.keep_alive = 10;

    ci.tls_config = tls_config;

    ip_addr_t ip;
    IP4_ADDR(&ip, 137, 135, 83, 217);
    // IP4_ADDR(&ip, 20, 79, 70, 109);

    err_t err = mqtt_client_connect(client, &ip, 8883, mqtt_connection_cb, 0, &ci);

    char payload[] = "Hello MQTT World";
    u8_t qos = 2;
    u8_t retain = 0;
    while (true)
    {
        switch (mqttStatus)
        {
        case 0:
            break;
        case 1:
            mqtt_set_inpub_callback(client, incoming_publish_cb, incoming_data_cb, NULL);
            err = mqtt_subscribe(client, "MyTopic", 1, sub_request_cb, NULL);
            break;

        case 2:
            err = mqtt_publish(client, "MyTopic", payload, strlen(payload), qos, retain, pub_request_cb, client);
            break;
        }
        sleep_ms(2000);
    }
}

Page 205 Full listing not in book

MQTT lwipopts.h

#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
#define _LWIPOPTS_EXAMPLE_COMMONH_H

// Common settings used in most of the pico_w examples
// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html for details)

// allow override in some examples
#ifndef NO_SYS
#define NO_SYS 1
#endif
// allow override in some examples
#ifndef LWIP_SOCKET
#define LWIP_SOCKET 0
#endif
#if PICO_CYW43_ARCH_POLL
#define MEM_LIBC_MALLOC 1
#else
// MEM_LIBC_MALLOC is incompatible with non polling versions
#define MEM_LIBC_MALLOC 0
#endif
#define MEM_ALIGNMENT 4
#define MEM_SIZE 4000
#define MEMP_NUM_TCP_SEG 32
#define MEMP_NUM_ARP_QUEUE 10
#define PBUF_POOL_SIZE 24
#define LWIP_ARP 1
#define LWIP_ETHERNET 1
#define LWIP_ICMP 1
#define LWIP_RAW 1
#define TCP_WND (8 * TCP_MSS)
#define TCP_MSS 1460
#define TCP_SND_BUF (8 * TCP_MSS)
#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
#define LWIP_NETIF_STATUS_CALLBACK 1
#define LWIP_NETIF_LINK_CALLBACK 1
#define LWIP_NETIF_HOSTNAME 1
#define LWIP_NETCONN 0
#define MEM_STATS 0
#define SYS_STATS 0
#define MEMP_STATS 0
#define LINK_STATS 0
// #define ETH_PAD_SIZE 2
#define LWIP_CHKSUM_ALGORITHM 3
#define LWIP_DHCP 1
#define LWIP_IPV4 1
#define LWIP_TCP 1
#define LWIP_UDP 1
#define LWIP_DNS 1
#define LWIP_TCP_KEEPALIVE 1
#define LWIP_NETIF_TX_SINGLE_PBUF 1
#define DHCP_DOES_ARP_CHECK 0
#define LWIP_DHCP_DOES_ACD_CHECK 0

#ifndef NDEBUG
#define LWIP_DEBUG 1
#define LWIP_STATS 1
#define LWIP_STATS_DISPLAY 1
#endif

#define ETHARP_DEBUG LWIP_DBG_OFF
#define NETIF_DEBUG LWIP_DBG_OFF
#define PBUF_DEBUG LWIP_DBG_OFF
#define API_LIB_DEBUG LWIP_DBG_OFF
#define API_MSG_DEBUG LWIP_DBG_OFF
#define SOCKETS_DEBUG LWIP_DBG_OFF
#define ICMP_DEBUG LWIP_DBG_OFF
#define INET_DEBUG LWIP_DBG_OFF
#define IP_DEBUG LWIP_DBG_OFF
#define IP_REASS_DEBUG LWIP_DBG_OFF
#define RAW_DEBUG LWIP_DBG_OFF
#define MEM_DEBUG LWIP_DBG_OFF
#define MEMP_DEBUG LWIP_DBG_OFF
#define SYS_DEBUG LWIP_DBG_OFF
#define TCP_DEBUG LWIP_DBG_OFF
#define TCP_INPUT_DEBUG LWIP_DBG_OFF
#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
#define TCP_RTO_DEBUG LWIP_DBG_OFF
#define TCP_CWND_DEBUG LWIP_DBG_OFF
#define TCP_WND_DEBUG LWIP_DBG_OFF
#define TCP_FR_DEBUG LWIP_DBG_OFF
#define TCP_QLEN_DEBUG LWIP_DBG_OFF
#define TCP_RST_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_OFF
#define TCPIP_DEBUG LWIP_DBG_OFF
#define PPP_DEBUG LWIP_DBG_OFF
#define SLIP_DEBUG LWIP_DBG_OFF
#define DHCP_DEBUG LWIP_DBG_OFF

#undef TCP_WND
#define TCP_WND 16384
#undef MEM_SIZE
#define MEM_SIZE 8000

#define LWIP_ALTCP 1
//#define LWIP_ALTCP_TLS 1
//#define LWIP_ALTCP_TLS_MBEDTLS 1

#define LWIP_DEBUG 1
#define ALTCP_MBEDTLS_DEBUG LWIP_DBG_ON
#define MQTT_DEBUG LWIP_DBG_ON
#define MEMP_NUM_SYS_TIMEOUT (LWIP_NUM_SYS_TIMEOUT_INTERNAL + 1)
#define MQTT_REQ_MAX_IN_FLIGHT (5)

#endif /* __LWIPOPTS_H__ */

Page 205 Full listing not in book

MQTT Cmakelist.txt

cmake_minimum_required(VERSION 3.13)
set(PICO_BOARD pico_w)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

include(pico_sdk_import.cmake)
project(PicoW C CXX ASM)
pico_sdk_init()

add_executable(main
main.c
)

target_include_directories(main PRIVATE ${CMAKE_CURRENT_LIST_DIR})

target_link_libraries(main pico_stdlib pico_cyw43_arch_lwip_threadsafe_background pico_lwip_mqtt)
pico_add_extra_outputs(main)

Page 205 Full listing not in book

MQTT TLS  main program

#include <stdio.h>

#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"
#include "lwip/ip_addr.h"
#include "setupWifi.h"
#include "lwip/altcp.h"
#include "lwip/altcp_tls.h"
#include "lwip/apps/mqtt.h"

int mqttStatus = 0;

void mqtt_connection_cb(mqtt_client_t *client, void *arg, mqtt_connection_status_t status)
{
    if (status == MQTT_CONNECT_ACCEPTED)
    {
        mqttStatus = 1;
    }
}

static void pub_request_cb(void *arg, err_t result)
{
    printf("Publish result: %d\n", result);
    mqtt_client_t *client = (mqtt_client_t *)arg;
}

void sub_request_cb(void *arg, err_t result)
{
    printf("Subscribe result: %d\n", result);
    mqttStatus = 2;
}

static void incoming_publish_cb(void *arg, const char *topic, u32_t tot_len)
{
    printf("Topic %s. %d\n", topic, tot_len);
}

static void incoming_data_cb(void *arg, const u8_t *data, u16_t len, u8_t flags)
{
    char *payload = (char *)data;
    printf("payload\n%.*s\n", len, payload);
}

int main()
{
    stdio_init_all();
    connect();

    struct altcp_tls_config *tls_config = altcp_tls_create_config_client(NULL, 0);

    mqtt_client_t *client = mqtt_client_new();

    struct mqtt_connect_client_info_t ci;
    memset(&ci, 0, sizeof(ci));
    ci.client_id = "MyPicoW";
    ci.keep_alive = 10;

    ci.tls_config = tls_config;

    ip_addr_t ip;
    IP4_ADDR(&ip, 137, 135, 83, 217);
    // IP4_ADDR(&ip, 20, 79, 70, 109);

    err_t err = mqtt_client_connect(client, &ip, 8883, mqtt_connection_cb, 0, &ci);

    char payload[] = "Hello MQTT World";
    u8_t qos = 2;
    u8_t retain = 0;
    while (true)
    {
        switch (mqttStatus)
        {
        case 0:
            break;
        case 1:
            mqtt_set_inpub_callback(client, incoming_publish_cb, incoming_data_cb, NULL);
            err = mqtt_subscribe(client, "MyTopic", 1, sub_request_cb, NULL);
            break;

        case 2:
            err = mqtt_publish(client, "MyTopic", payload, strlen(payload), qos, retain, pub_request_cb, client);
            break;
        }
        sleep_ms(2000);
    }
}

Page 205 Full listing not in book

MQTT TLS lwipopts.h

#ifndef _LWIPOPTS_EXAMPLE_COMMONH_H
#define _LWIPOPTS_EXAMPLE_COMMONH_H

// Common settings used in most of the pico_w examples
// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html for details)

// allow override in some examples
#ifndef NO_SYS
#define NO_SYS 1
#endif
// allow override in some examples
#ifndef LWIP_SOCKET
#define LWIP_SOCKET 0
#endif
#if PICO_CYW43_ARCH_POLL
#define MEM_LIBC_MALLOC 1
#else
// MEM_LIBC_MALLOC is incompatible with non polling versions
#define MEM_LIBC_MALLOC 0
#endif
#define MEM_ALIGNMENT 4
#define MEM_SIZE 4000
#define MEMP_NUM_TCP_SEG 32
#define MEMP_NUM_ARP_QUEUE 10
#define PBUF_POOL_SIZE 24
#define LWIP_ARP 1
#define LWIP_ETHERNET 1
#define LWIP_ICMP 1
#define LWIP_RAW 1
#define TCP_WND (8 * TCP_MSS)
#define TCP_MSS 1460
#define TCP_SND_BUF (8 * TCP_MSS)
#define TCP_SND_QUEUELEN ((4 * (TCP_SND_BUF) + (TCP_MSS - 1)) / (TCP_MSS))
#define LWIP_NETIF_STATUS_CALLBACK 1
#define LWIP_NETIF_LINK_CALLBACK 1
#define LWIP_NETIF_HOSTNAME 1
#define LWIP_NETCONN 0
#define MEM_STATS 0
#define SYS_STATS 0
#define MEMP_STATS 0
#define LINK_STATS 0
// #define ETH_PAD_SIZE 2
#define LWIP_CHKSUM_ALGORITHM 3
#define LWIP_DHCP 1
#define LWIP_IPV4 1
#define LWIP_TCP 1
#define LWIP_UDP 1
#define LWIP_DNS 1
#define LWIP_TCP_KEEPALIVE 1
#define LWIP_NETIF_TX_SINGLE_PBUF 1
#define DHCP_DOES_ARP_CHECK 0
#define LWIP_DHCP_DOES_ACD_CHECK 0

#ifndef NDEBUG
#define LWIP_DEBUG 1
#define LWIP_STATS 1
#define LWIP_STATS_DISPLAY 1
#endif

#define ETHARP_DEBUG LWIP_DBG_OFF
#define NETIF_DEBUG LWIP_DBG_OFF
#define PBUF_DEBUG LWIP_DBG_OFF
#define API_LIB_DEBUG LWIP_DBG_OFF
#define API_MSG_DEBUG LWIP_DBG_OFF
#define SOCKETS_DEBUG LWIP_DBG_OFF
#define ICMP_DEBUG LWIP_DBG_OFF
#define INET_DEBUG LWIP_DBG_OFF
#define IP_DEBUG LWIP_DBG_OFF
#define IP_REASS_DEBUG LWIP_DBG_OFF
#define RAW_DEBUG LWIP_DBG_OFF
#define MEM_DEBUG LWIP_DBG_OFF
#define MEMP_DEBUG LWIP_DBG_OFF
#define SYS_DEBUG LWIP_DBG_OFF
#define TCP_DEBUG LWIP_DBG_OFF
#define TCP_INPUT_DEBUG LWIP_DBG_OFF
#define TCP_OUTPUT_DEBUG LWIP_DBG_OFF
#define TCP_RTO_DEBUG LWIP_DBG_OFF
#define TCP_CWND_DEBUG LWIP_DBG_OFF
#define TCP_WND_DEBUG LWIP_DBG_OFF
#define TCP_FR_DEBUG LWIP_DBG_OFF
#define TCP_QLEN_DEBUG LWIP_DBG_OFF
#define TCP_RST_DEBUG LWIP_DBG_OFF
#define UDP_DEBUG LWIP_DBG_OFF
#define TCPIP_DEBUG LWIP_DBG_OFF
#define PPP_DEBUG LWIP_DBG_OFF
#define SLIP_DEBUG LWIP_DBG_OFF
#define DHCP_DEBUG LWIP_DBG_OFF

#undef TCP_WND
#define TCP_WND 16384
#undef MEM_SIZE
#define MEM_SIZE 8000

#define LWIP_ALTCP 1
#define LWIP_ALTCP_TLS 1
#define LWIP_ALTCP_TLS_MBEDTLS 1

#define LWIP_DEBUG 1
#define ALTCP_MBEDTLS_DEBUG LWIP_DBG_ON
#define MQTT_DEBUG LWIP_DBG_ON
#define MEMP_NUM_SYS_TIMEOUT (LWIP_NUM_SYS_TIMEOUT_INTERNAL + 1)
#define MQTT_REQ_MAX_IN_FLIGHT (5)

#endif /* __LWIPOPTS_H__ */

Page 205 Full listing not in book

MQTT TLS mbedtls_config.h

//Hardware config
#define MBEDTLS_NO_PLATFORM_ENTROPY
#define MBEDTLS_ENTROPY_HARDWARE_ALT
#define MBEDTLS_HAVE_TIME

//error reporting
#define MBEDTLS_ERROR_C
//used by LwIP
#define MBEDTLS_ENTROPY_C
#define MBEDTLS_CTR_DRBG_C

//EC KEY EXCHANGE
#define MBEDTLS_KEY_EXCHANGE_ECDHE_RSA_ENABLED
#define MBEDTLS_ECDH_C
#define MBEDTLS_ECDSA_C
#define MBEDTLS_ECP_C

/* Short Weierstrass curves (supporting ECP, ECDH, ECDSA) */
#define MBEDTLS_ECP_DP_SECP192R1_ENABLED
#define MBEDTLS_ECP_DP_SECP224R1_ENABLED
#define MBEDTLS_ECP_DP_SECP256R1_ENABLED
#define MBEDTLS_ECP_DP_SECP384R1_ENABLED
#define MBEDTLS_ECP_DP_SECP521R1_ENABLED
#define MBEDTLS_ECP_DP_SECP192K1_ENABLED
#define MBEDTLS_ECP_DP_SECP224K1_ENABLED
#define MBEDTLS_ECP_DP_SECP256K1_ENABLED
#define MBEDTLS_ECP_DP_BP256R1_ENABLED
#define MBEDTLS_ECP_DP_BP384R1_ENABLED
#define MBEDTLS_ECP_DP_BP512R1_ENABLED

//RSA KEY EXCHANGE
#define MBEDTLS_KEY_EXCHANGE_RSA_ENABLED
#define MBEDTLS_RSA_C

//general key exchange
#define MBEDTLS_PKCS1_V15
#define MBEDTLS_BIGNUM_C
#define MBEDTLS_PK_C
#define MBEDTLS_PK_PARSE_C

//encryption
#define MBEDTLS_AES_C
#define MBEDTLS_CCM_C
#define MBEDTLS_CIPHER_MODE_CBC
#define MBEDTLS_AES_FEWER_TABLES
#define MBEDTLS_GCM_C

//certs
#define MBEDTLS_X509_CRT_PARSE_C
#define MBEDTLS_X509_USE_C
#define MBEDTLS_OID_C
#define MBEDTLS_ASN1_PARSE_C
#define MBEDTLS_ASN1_WRITE_C

//hash methods
#define MBEDTLS_SHA1_C
#define MBEDTLS_SHA224_C
#define MBEDTLS_SHA256_C
#define MBEDTLS_SHA512_C

//ECDHE-RSA-AES256-GCM-SHA384
//TLS
#define MBEDTLS_CIPHER_C
#define MBEDTLS_SSL_TLS_C
#define MBEDTLS_MD_C

//enable client modes and TLS
#define MBEDTLS_SSL_CLI_C
#define MBEDTLS_SSL_SERVER_NAME_INDICATION

//enable TLS 1.2
#define MBEDTLS_SSL_PROTO_TLS1_2

#include "/home/pi/pico/pico-sdk/lib/mbedtls/include/mbedtls/check_config.h"

Page 205 Full listing not in book

MQTT TLS CMakeLists.txt

cmake_minimum_required(VERSION 3.13)
set(PICO_BOARD pico_w)
set(CMAKE_C_STANDARD 11)
set(CMAKE_CXX_STANDARD 17)

include(pico_sdk_import.cmake)
project(PicoW C CXX ASM)
pico_sdk_init()

add_executable(main
main.c
)

target_include_directories(main PRIVATE ${CMAKE_CURRENT_LIST_DIR})

target_link_libraries(main pico_stdlib pico_cyw43_arch_lwip_threadsafe_background pico_lwip_mqtt pico_lwip_mbedtls
pico_mbedtls)
pico_add_extra_outputs(main)

Page 207  MQTT HiveMQ main program Note works with modified mqtt.h and mqtt.c

#include <stdio.h>
#include "pico/stdlib.h"
#include "pico/cyw43_arch.h"
#include "lwip/ip_addr.h"
#include "setupWifi.h"
#include "lwip/altcp.h"
#include "lwip/altcp_tls.h"
#include "lwip/apps/mqtt.h"

int mqttStatus = 0;

void mqtt_connection_cb(mqtt_client_t *client, void *arg, mqtt_connection_status_t status)
{
    if (status == MQTT_CONNECT_ACCEPTED)
    {
        mqttStatus = 1;
    }
}

static void pub_request_cb(void *arg, err_t result)
{
    printf("Publish result: %d\n", result);
    mqtt_client_t *client = (mqtt_client_t *)arg;
}

void sub_request_cb(void *arg, err_t result)
{
    printf("Subscribe result: %d\n", result);
    mqttStatus = 2;
}

static void incoming_publish_cb(void *arg, const char *topic, u32_t tot_len)
{
    printf("Topic %s. %d\n", topic, tot_len);
}

static void incoming_data_cb(void *arg, const u8_t *data, u16_t len, u8_t flags)
{
    char *payload = (char *)data;
    printf("payload\n%.*s\n", len, payload);
}

int main()
{
    stdio_init_all();
    connect();

    struct altcp_tls_config *tls_config = altcp_tls_create_config_client(NULL, 0);
    mqtt_client_t *client = mqtt_client_new();

    struct mqtt_connect_client_info_t ci;
    memset(&ci, 0, sizeof(ci));
    ci.client_id = "MyPicoW";
    ci.client_user = "username";
    ci.client_pass = "password";
    ci.keep_alive = 10;
    ci.tls_config = tls_config;
    strncpy(ci.domName, "1a6d2dccd35744888e4b7c6f8e65f613.s2.eu.hivemq.cloud", 100);
    ip_addr_t ip;
    // IP4_ADDR(&ip, 137, 135, 83, 217);
    IP4_ADDR(&ip, 20, 79, 70, 109);

    err_t err = mqtt_client_connect(client, &ip, 8883, mqtt_connection_cb, 0, &ci);

    char payload[] = "Hello MQTT World";
    u8_t qos = 2;
    u8_t retain = 0;
    while (true)
    {
        switch (mqttStatus)
        {
        case 0:
            break;
        case 1:
            mqtt_set_inpub_callback(client, incoming_publish_cb, incoming_data_cb, NULL);
            err = mqtt_subscribe(client, "MyTopic", 1, sub_request_cb, NULL);
            break;

        case 2:
            err = mqtt_publish(client, "MyTopic", payload, strlen(payload), qos, retain, pub_request_cb, client);
            break;
        }
        sleep_ms(2000);
    }
}