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ellebi2000ellebi2000peterharperuk
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mqtt_client_test (#498)
* added mqtt pub/sub example * added mqtt pub/sub example * removed unnecessary comments * Move mqtt example to wifi folder * Tidy up mqtt example Fix review comments and build warnings. Use MQTT_SERVER build variable instead of hard coding IP address. Make a DNS request for the server. Use async timer for publishing the temperature. * Add support for username and password * Add TLS support Move the code down one level * Add some more topics print, just print the message to stdout ping, publish uptime to pong exit, quit the client * Add will topic /online Add some defines for some magic numbers * Unique topic names per device Disabled by default with MQTT_UNIQUE_TOPIC * Some MQTT updates Change /pong to /uptime Display a message if MQTT_SERVER is not defined Put picow_ in the name like the other examples Add details to the readme! --------- Co-authored-by: ellebi2000 <[email protected]> Co-authored-by: Peter Harper <[email protected]>
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‎README.md

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[picow_httpd](pico_w/wifi/httpd) | Runs a LWIP HTTP server test app
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[picow_http_client](pico_w/wifi/http_client) | Demonstrates how to make http and https requests
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[picow_http_client_verify](pico_w/wifi/http_client) | Demonstrates how to make a https request with server authentication
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[picow_mqtt_client](pico_w/wifi/mqtt) | Demonstrates how to implement an MQTT client application
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#### FreeRTOS examples
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‎pico_w/wifi/CMakeLists.txt

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add_subdirectory_exclude_platforms(tcp_server)
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add_subdirectory_exclude_platforms(udp_beacon)
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add_subdirectory_exclude_platforms(http_client)
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add_subdirectory_exclude_platforms(mqtt)
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if (NOT PICO_MBEDTLS_PATH)
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message("Skipping tls examples as PICO_MBEDTLS_PATH is not defined")

‎pico_w/wifi/lwipopts_examples_common.h

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#define MEM_LIBC_MALLOC 0
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#endif
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#define MEM_ALIGNMENT 4
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#ifndef MEM_SIZE
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#define MEM_SIZE 4000
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#endif
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#define MEMP_NUM_TCP_SEG 32
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#define MEMP_NUM_ARP_QUEUE 10
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#define PBUF_POOL_SIZE 24

‎pico_w/wifi/mqtt/CMakeLists.txt

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# Define the host name of the MQTT server in an environment variable or pass it to cmake,
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# e.g. cmake -DMQTT_SERVER=myserver ..
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if (DEFINED ENV{MQTT_SERVER} AND (NOT MQTT_SERVER))
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set(MQTT_SERVER $ENV{MQTT_SERVER})
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message("Using MQTT_SERVER from environment ('${MQTT_SERVER}')")
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endif()
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if (NOT MQTT_SERVER)
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message("Skipping MQTT example as MQTT_SERVER is not defined")
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return()
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endif()
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# Define the name of an MQTT broker/server to enable this example
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set(MQTT_SERVER "${MQTT_SERVER}" CACHE INTERNAL "MQTT server for examples")
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if (DEFINED ENV{MQTT_USERNAME} AND (NOT MQTT_USERNAME))
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set(MQTT_USERNAME $ENV{MQTT_USERNAME})
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message("Using MQTT_USERNAME from environment ('${MQTT_USERNAME}')")
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endif()
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set(MQTT_USERNAME "${MQTT_USERNAME}" CACHE INTERNAL "MQTT user name for examples")
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if (DEFINED ENV{MQTT_PASSWORD} AND (NOT MQTT_PASSWORD))
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set(MQTT_PASSWORD $ENV{MQTT_PASSWORD})
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message("Using MQTT_PASSWORD from environment")
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endif()
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set(MQTT_PASSWORD "${MQTT_PASSWORD}" CACHE INTERNAL "MQTT password for examples")
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# Set path to the certificate include file
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if (NOT MQTT_CERT_PATH)
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set(MQTT_CERT_PATH ${CMAKE_CURRENT_LIST_DIR}/certs/${MQTT_SERVER})
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endif()
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# Set the name of the certificate include file
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if (NOT MQTT_CERT_INC)
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set(MQTT_CERT_INC mqtt_client.inc)
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endif()
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set(TARGET_NAME picow_mqtt_client)
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add_executable(${TARGET_NAME}
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mqtt_client.c
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)
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target_link_libraries(${TARGET_NAME}
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pico_stdlib
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hardware_adc
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pico_cyw43_arch_lwip_threadsafe_background
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pico_lwip_mqtt
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pico_mbedtls
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pico_lwip_mbedtls
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)
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target_include_directories(${TARGET_NAME} PRIVATE
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${CMAKE_CURRENT_LIST_DIR}
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${CMAKE_CURRENT_LIST_DIR}/.. # for our common lwipopts or any other standard includes, if required
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)
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target_compile_definitions(${TARGET_NAME} PRIVATE
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WIFI_SSID=\"${WIFI_SSID}\"
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WIFI_PASSWORD=\"${WIFI_PASSWORD}\"
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MQTT_SERVER=\"${MQTT_SERVER}\"
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)
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if (EXISTS "${MQTT_CERT_PATH}/${MQTT_CERT_INC}")
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target_compile_definitions(${TARGET_NAME} PRIVATE
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MQTT_CERT_INC=\"${MQTT_CERT_INC}\" # contains the tls certificates for MQTT_SERVER needed by the client
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ALTCP_MBEDTLS_AUTHMODE=MBEDTLS_SSL_VERIFY_REQUIRED
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)
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target_include_directories(${TARGET_NAME} PRIVATE
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${MQTT_CERT_PATH}
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)
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endif()
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if (MQTT_USERNAME AND MQTT_PASSWORD)
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target_compile_definitions(${TARGET_NAME} PRIVATE
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MQTT_USERNAME=\"${MQTT_USERNAME}\"
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MQTT_PASSWORD=\"${MQTT_PASSWORD}\"
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)
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endif()
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pico_add_extra_outputs(${TARGET_NAME})
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# Ignore warnings from lwip code
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set_source_files_properties(
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${PICO_LWIP_PATH}/src/apps/altcp_tls/altcp_tls_mbedtls.c
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PROPERTIES
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COMPILE_OPTIONS "-Wno-unused-result"
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)

‎pico_w/wifi/mqtt/README

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# Quick start
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To use this example you will need to install an MQTT server on your network.
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To install the Mosquitto MQTT client on a Raspberry Pi Linux device run the following...
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```
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sudo apt install mosquitto
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sudo apt install mosquitto-clients
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```
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Check it works...
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```
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mosquitto_pub -t test_topic -m "Yes it works" -r
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mosquitto_sub -t test_topic -C 1
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```
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To allow an external client to connect to the server you will have to change the configuration. Add the following to /etc/mosquitto/conf.d/mosquitto.conf
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```
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allow_anonymous true
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listener 1883 0.0.0.0
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```
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Then restart the service.
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```
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sudo service mosquitto restart
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```
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When building the code set the host name of the MQTT server, e.g.
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```
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export MQTT_SERVER=myhost
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cmake ..
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```
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The example should publish its core temperature to the /temperature topic. You can subscribe to this topic from another machine.
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```
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mosquitto_sub -h $MQTT_SERVER -t '/temperature'
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```
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You can turn the led on and off by publishing messages.
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```
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mosquitto_pub -h $MQTT_SERVER -t '/led' -m on
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mosquitto_pub -h $MQTT_SERVER -t '/led' -m off
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```
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# Security
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If your server has a username and password, you can set these with the following variables.
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```
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export MQTT_USERNAME=user
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export MQTT_PASSWORD=pass
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```
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Be aware that these details are sent in plain text unless you use TLS.
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## Using TLS
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To use TLS and client server authentication you need some keys and certificates for the client and server.
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The `certs/makecerts.sh` script demonstrates a way to make these.
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It creates a folder named after `MQTT_SERVER` containing all the required files.
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From these files it generates a header file `mqtt_client.inc` included by the code.
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Your server will have to be configured to use TLS and the port 8883 rather than the non-TLS port 1883.
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```
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listener 1883 127.0.0.1
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listener 8883 0.0.0.0
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allow_anonymous true
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cafile /etc/mosquitto/ca_certificates/ca.crt
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certfile /etc/mosquitto/certs/server.crt
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keyfile /etc/mosquitto/certs/server.key
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require_certificate true
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```
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To connect to your server with the mosquitto tools in linux you will have to pass extra parameters.
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```
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mosquitto_pub -h $MQTT_SERVER --cafile $MQTT_SERVER/ca.crt --key $MQTT_SERVER/client.key --cert $MQTT_SERVER/client.crt -t /led -m on
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mosquitto_sub -h $MQTT_SERVER --cafile $MQTT_SERVER/ca.crt --key $MQTT_SERVER/client.key --cert $MQTT_SERVER/client.crt -t "/temperature"
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```
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There are some shell scripts in the certs folder to reduce the amount of typing assuming `MQTT_SERVER` is defined.
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```
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cd certs
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./pub.sh /led on
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./sub.sh /temperature
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```

‎pico_w/wifi/mqtt/certs/.gitignore

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*/
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‎pico_w/wifi/mqtt/certs/makecerts.sh

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#!/usr/bin/bash
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if [ "${PWD##*/}" != "certs" ]; then
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echo Run this in the certs folder
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exit 1
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fi
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if [ -z "$MQTT_SERVER" ]; then
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echo Define MQTT_SERVER
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exit 1
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fi
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SERVER_NAME=$MQTT_SERVER
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if [ -d "$SERVER_NAME" ]; then
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echo Run \"rm -fr $SERVER_NAME\" to regenerate these keys
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exit 1
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fi
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mkdir $SERVER_NAME
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echo Generating keys in $PWD/$SERVER_NAME
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openssl genrsa -out $SERVER_NAME/ca.key 2048
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openssl req -new -x509 -days 99999 -key $SERVER_NAME/ca.key -out $SERVER_NAME/ca.crt -subj "/C=UK/ST=Cambridgeshire/L=Cambridge/O=Raspberry Pi Ltd/OU=Software/CN=rpiroot"
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openssl genrsa -out $SERVER_NAME/server.key 2048
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openssl req -new -out $SERVER_NAME/server.csr -key $SERVER_NAME/server.key -subj "/C=UK/ST=Cambridgeshire/L=Cambridge/O=Raspberry Pi Ltd/OU=Software/CN=$SERVER_NAME"
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openssl x509 -req -in $SERVER_NAME/server.csr -CA $SERVER_NAME/ca.crt -CAkey $SERVER_NAME/ca.key -CAcreateserial -out $SERVER_NAME/server.crt -days 9999
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openssl genrsa -out $SERVER_NAME/client.key 2048
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openssl req -new -out $SERVER_NAME/client.csr -key $SERVER_NAME/client.key -subj "/C=UK/ST=Cambridgeshire/L=Cambridge/O=Raspberry Pi Ltd/OU=Software/CN=$SERVER_NAME"
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openssl x509 -req -in $SERVER_NAME/client.csr -CA $SERVER_NAME/ca.crt -CAkey $SERVER_NAME/ca.key -CAcreateserial -out $SERVER_NAME/client.crt -days 999
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echo -n \#define TLS_ROOT_CERT \" > $SERVER_NAME/mqtt_client.inc
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cat $SERVER_NAME/ca.crt | awk '{printf "%s\\n\\\n", $0}' >> $SERVER_NAME/mqtt_client.inc
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echo "\"" >> $SERVER_NAME/mqtt_client.inc
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echo >> $SERVER_NAME/mqtt_client.inc
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echo -n \#define TLS_CLIENT_KEY \" >> $SERVER_NAME/mqtt_client.inc
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cat $SERVER_NAME/client.key | awk '{printf "%s\\n\\\n", $0}' >> $SERVER_NAME/mqtt_client.inc
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echo "\"" >> $SERVER_NAME/mqtt_client.inc
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echo >> $SERVER_NAME/mqtt_client.inc
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echo -n \#define TLS_CLIENT_CERT \" >> $SERVER_NAME/mqtt_client.inc
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cat $SERVER_NAME/client.crt | awk '{printf "%s\\n\\\n", $0}' >> $SERVER_NAME/mqtt_client.inc
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echo "\"" >> $SERVER_NAME/mqtt_client.inc

‎pico_w/wifi/mqtt/certs/pub.sh

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#/usr/bin/bash
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if [ -z "$MQTT_SERVER" ]; then
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echo Define MQTT_SERVER
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exit 1
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fi
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mosquitto_pub -h $MQTT_SERVER --cafile $MQTT_SERVER/ca.crt --key $MQTT_SERVER/client.key --cert $MQTT_SERVER/client.crt -t "$1" -m "$2"
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‎pico_w/wifi/mqtt/certs/sub.sh

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#/usr/bin/bash
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if [ -z "$MQTT_SERVER" ]; then
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echo Define MQTT_SERVER
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exit 1
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fi
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mosquitto_sub -h $MQTT_SERVER --cafile $MQTT_SERVER/ca.crt --key $MQTT_SERVER/client.key --cert $MQTT_SERVER/client.crt -t "$1"
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‎pico_w/wifi/mqtt/lwipopts.h

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#ifndef _LWIPOPTS_H
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#define _LWIPOPTS_H
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// Need more memory for TLS
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#ifdef MQTT_CERT_INC
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#define MEM_SIZE 8000
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#endif
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// Generally you would define your own explicit list of lwIP options
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// (see https://www.nongnu.org/lwip/2_1_x/group__lwip__opts.html)
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//
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// This example uses a common include to avoid repetition
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#include "lwipopts_examples_common.h"
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#define MEMP_NUM_SYS_TIMEOUT (LWIP_NUM_SYS_TIMEOUT_INTERNAL+1)
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#ifdef MQTT_CERT_INC
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#define LWIP_ALTCP 1
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#define LWIP_ALTCP_TLS 1
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#define LWIP_ALTCP_TLS_MBEDTLS 1
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#ifndef NDEBUG
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#define ALTCP_MBEDTLS_DEBUG LWIP_DBG_ON
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#endif
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/* TCP WND must be at least 16 kb to match TLS record size
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or you will get a warning "altcp_tls: TCP_WND is smaller than the RX decrypion buffer, connection RX might stall!" */
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#undef TCP_WND
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#define TCP_WND 16384
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#endif // MQTT_CERT_INC
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// This defaults to 4
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#define MQTT_REQ_MAX_IN_FLIGHT 5
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#endif

‎pico_w/wifi/mqtt/mbedtls_config.h

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#ifndef MBEDTLS_CONFIG_TLS_CLIENT_H
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#define MBEDTLS_CONFIG_TLS_CLIENT_H
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#include "mbedtls_config_examples_common.h"
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#endif

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