ESP-Nodes/ESP32_Temperture-Node/README.md
2024-07-04 00:33:19 -04:00

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# ESP32 MQTT SSL Temperature Node
<!-- BMP280 comes in 3.3V and 5V versions. 5V version is I2C and has 4 terminals; 3.3V version is IPS and has 6 terminals AHT10 Arduino sensor -->
## MQTT Mosquito Broker
<p>Mosquitto broker can be easily deployed using Docker compose file shown below. In the example below, MQTT broker listens to the ports 1883 (unecrypted) and 8883 (encrypted SSL). </p>
> [!NOTE]
> Compose file below declares two volumes (config and data) to persistantly store Mosquitto configuration and data.
```text
version: "3.8"
services:
mosquitto-esp32:
image: eclipse-mosquitto:latest
volumes:
- /srv/dev-disk-by-label/docker/volumes/mosquitto/config:/mosquitto/config
- /srv/dev-disk-by-label/docker/volumes/mosquitto/data:/mosquitto/data
networks:
- IoT
ports:
- 1883:1883
- 8883:8883
- 9001:9001
restart: unless-stopped
networks:
IoT:
external: true
```
<p><i>mosquitto.conf</i></p>
> [!NOTE]
> If you are using IP addresses, then issue certificates and keys to the corresponding IP address of MQTT brocker
``` text
## List ports listen to
listener 1883
listener 8883
cafile /mosquitto/config/certs/esp32_ca.crt
certfile /mosquitto/config/certs/esp32.crt
keyfile /mosquitto/config/certs/esp32.key
allow_anonymous true
persistence true
persistence_location /srv/dev-disk-by-label/docker/columes/mosquitto/data/
```
## ESP32 MQTT Client
<p>The two lines of code shown below are the most crucial as they are responsible for connecting ESP32 to the MQTT broker.</p>
> [!NOTE]
> A set of SSL certificates and key used by ESP32 MQTT client must correspond to ones used by MQTT brocker. Otherwise, secure connection won't be established.
```C
espClientSSL.setCACert(NODE_CERT_CA);
espClientSSL.setCertificate(NODE_CERT_CRT);
espClientSSL.setPrivateKey(NODE_CERT_PRIVATE);
connection.setServer(mqtt_server, 8883); // mqtt_server -> 192.168.50.16
```
<p><i>secrets.h</i></p>
> [!NOTE]
> Create file called secrets.h to store configuration information about Wi-Fi, and encryption keys, but exclude it from being pushed to GitHub
```text
const char* WIFI_SSID = "IoT_bots";
const char* WIFI_PASSWORD = "212212212";
const char* mqtt_server = "192.168.50.16";
// MQTT Broker Root CA
static const char NODE_CERT_CA[] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
< Cut&Paste content of CA certificate over here >
-----END CERTIFICATE-----
)EOF";
// MQTT Client Certificate
static const char NODE_CERT_CRT [] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
< Cut&Paste content of client certificate over here >
-----END CERTIFICATE-----
)EOF";
// MQTT Client Key
static const char NODE_CERT_PRIVATE [] PROGMEM = R"EOF(
-----BEGIN CERTIFICATE-----
< Cut&Paste content of client key over here >
-----END CERTIFICATE-----
)EOF";
```
## Issuing Self-Generated SSL Certificates & Keys
```C
#################################################################
#Certificate generator for TLS encryption
#################################################################
openssl req -new -x509 -days 365 -extensions v3_ca -keyout ca.key -out ca.crt -passout pass:1234 -subj '/CN=TrustedCA.net'
#If you generating self-signed certificates the CN can be anything
openssl genrsa -out mosquitto.key 2048
openssl req -out mosquitto.csr -key mosquitto.key -new -subj '/CN=Mosquitto_borker_adress'
openssl x509 -req -in mosquitto.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out mosquitto.crt -days 365 -passin pass:1234
#Mostly the client verifies the adress of the mosquitto server, so its necessary to set the CN to the correct adress (eg. yourserver.com)!!!
#################################################################
#These certificates are only needed if the mosquitto broker requires a certificate for client autentithication (require_certificate is set to true in mosquitto config)
#################################################################
openssl genrsa -out esp.key 2048
openssl req -out esp.csr -key esp.key -new -subj '/CN=localhost'
openssl x509 -req -in esp.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out esp.crt -days 365 -passin pass:1234
#If the server (mosquitto) identifies the clients based on CN key, its necessary to set it to the correct value, else it can be blank. See the Mosquitto config.
==========================
openssl req -new -x509 -days 365 -extensions v3_ca -keyout ca.key -out ca.crt -passout pass:1234 -subj '/CN=myserver.dynamic-dns.net'
openssl genrsa -out mosquitto.key 2048
openssl req -out mosquitto.csr -key mosquitto.key -new -subj '/CN=localhost'
openssl x509 -req -in mosquitto.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out mosquitto.crt -days 365 -passin pass:1234
openssl genrsa -out esp.key 2048
openssl req -out esp.csr -key esp.key -new -subj '/CN=localhost'
openssl x509 -req -in esp.csr -CA ca.crt -CAkey ca.key -CAcreateserial -out esp.crt -days 365 -passin pass:1234
openssl genrsa -out esp32.key 2048
openssl req -new -x509 -days 365 -extensions v3_ca -keyout esp32_ca.key -out esp32_ca.crt -passout pass:1234 -subj '/CN=10.100.50.16'
openssl req -out esp32.csr -key esp32.key -new -subj '/CN=10.100.50.16'
openssl genrsa -out esp_node.key 2048
openssl req -out esp_node.csr -key esp_node.key -new -subj '/CN=localhost'
openssl x509 -req -in esp32.csr -CA esp32_ca.crt -CAkey esp32_ca.key -CAcreateserial -out esp_node.crt -days 365 -passin pass:1234
```