Add encryption via ESP-NOW

server/src/connect.cpp

@@ -0,0 +1,99 @@
+#include <cstdint>
+
+#include <Arduino.h>
+#include <WiFi.h>
+#include <esp_now.h>
+#include <esp_wifi.h>
+
+#include "connect.h"
+#include "secrets.h"
+
+uint8_t client_mac[6] = CLIENT_MAC;
+uint8_t server_mac[6] = SERVER_MAC;
+
+bool powerRemotePressed = false;
+bool resetRemotePressed = false;
+
+// -----------------------------------------
+
+void wifiSetupEncryption();
+
+void onDataSent(const uint8_t* mac_addr, esp_now_send_status_t status)
+{
+}
+
+void onDataRecv(const uint8_t* mac_addr, const uint8_t* data, int data_len)
+{
+	Serial.print("Received: ");
+	Serial.write(data, data_len);
+	Serial.println();
+
+	auto msg = String((const char*)data, data_len);
+
+	if (msg == "power_pressed") {
+		powerRemotePressed = true;
+	}
+	else if (msg == "power_released") {
+		powerRemotePressed = false;
+	}
+	else if (msg == "reset_pressed") {
+		resetRemotePressed = true;
+	}
+	else if (msg == "reset_released") {
+		resetRemotePressed = false;
+	}
+	else {
+		return;
+	}
+
+	String reply = msg + "_ack";
+	esp_now_send(client_mac, (const uint8_t*)reply.c_str(), reply.length());
+}
+
+void wifiSetup()
+{
+	WiFi.mode(WIFI_STA);
+	WiFi.setAutoReconnect(false);
+	WiFi.disconnect();
+	delay(100);
+
+	esp_wifi_set_channel(static_cast<uint8_t>(CHANNEL), WIFI_SECOND_CHAN_NONE);
+
+	wifiSetupEncryption();
+}
+
+void wifiSetupEncryption()
+{
+	esp_now_deinit();
+
+	if (esp_now_init() != ESP_OK) {
+		Serial.println("Failed to init ESP-NOW");
+		return;
+	}
+
+	if (esp_now_set_pmk((const uint8_t*)PMK) != ESP_OK) {
+		Serial.println("Failed to set PMK");
+		return;
+	}
+
+	auto peerInfo = esp_now_peer_info_t {
+		.channel = static_cast<uint8_t>(CHANNEL),
+		.encrypt = true,
+	};
+
+	memcpy(peerInfo.peer_addr, client_mac, 6);
+	memcpy(peerInfo.lmk, LMK, 16);
+
+	if (esp_now_add_peer(&peerInfo) != ESP_OK) {
+		Serial.println("Failed to add peer");
+		return;
+	}
+
+	esp_now_register_send_cb(onDataSent);
+	esp_now_register_recv_cb(onDataRecv);
+
+	Serial.println("Configured encryption!");
+}
+
+// https://docs.espressif.com/projects/arduino-esp32/en/latest/api/wifi.html
+// https://docs.arduino.cc/libraries/wifi/ (old)

server/src/connect.h

@@ -0,0 +1,6 @@
+#define CHANNEL 11
+
+extern bool powerRemotePressed;
+extern bool resetRemotePressed;
+
+void wifiSetup();

server/src/main.cpp

@@ -1,30 +1,21 @@
 #include <Arduino.h>
-#include <WiFi.h>
-#include <WiFiClient.h>
-#include <WiFiServer.h>
 
-#include "secrets.h"
-
-// Default gateway    = 192.168.4.1
-// Default IP address = 192.168.4.2
-
-#define PORT 1234
-#define CHANNEL 11
-#define HIDDEN true
-#define MAX_CONNECTION 1
+#include "connect.h"
 
 #define POWER_BUTTON_PIN 10
 #define RESET_BUTTON_PIN 2
+
 #define POWER_LED_PIN 3
 #define RESET_LED_PIN 1
 
 #define POWER_GATE_PIN 6
 #define RESET_GATE_PIN 7
 
-WiFiServer server(PORT, MAX_CONNECTION);
+int previousPowerButtonState = HIGH;
+int previousResetButtonState = HIGH;
 
-bool powerPressed = false;
-bool resetPressed = false;
+bool powerButtonPressed = false;
+bool resetButtonPressed = false;
 
 void processButtons();
 void setPowerPin(bool enable);
@@ -35,6 +26,9 @@ void setup()
 	Serial.begin(9600);
 	Serial.setDebugOutput(true);
 
+	pinMode(POWER_BUTTON_PIN, INPUT_PULLUP);
+	pinMode(RESET_BUTTON_PIN, INPUT_PULLUP);
+
 	pinMode(POWER_GATE_PIN, OUTPUT);
 	pinMode(POWER_LED_PIN, OUTPUT);
 	pinMode(RESET_GATE_PIN, OUTPUT);
@@ -43,85 +37,55 @@ void setup()
 	delay(3000);
 	Serial.println("Server booted!");
 
-	// Start button server
-	WiFi.softAP(SSID, PASSWORD, CHANNEL, HIDDEN, MAX_CONNECTION);
-	Serial.println("AP Started");
-	server.begin();
+	wifiSetup();
 }
 
 void loop()
 {
-	WiFiClient client = server.available();
-	if (client) {
-		Serial.println("Client connected");
+	delay(20); // used for button debounce
 
-		unsigned long start = 0;
-		while (client.connected()) {
-			if (client.available()) {
-				String msg = client.readStringUntil('\n');
-				Serial.print("Received: ");
-				Serial.println(msg);
+	int powerButtonState = digitalRead(POWER_BUTTON_PIN);
+	int resetButtonState = digitalRead(RESET_BUTTON_PIN);
 
-				if (msg == "power_pressed") {
-					powerPressed = true;
-				}
-				else if (msg == "power_released") {
-					powerPressed = false;
-				}
-				else if (msg == "reset_pressed") {
-					resetPressed = true;
-				}
-				else if (msg == "reset_released") {
-					resetPressed = false;
-				}
-
-				client.print("ACK\n");
-				Serial.println("Sent ACK");
-				start = millis();
-			}
-
-			// Kill lingering connections
-			if (start != 0 && millis() - start > 200) {
-				Serial.println("Client kill..");
-				break;
-			}
-
-			processButtons();
-		}
-
-		setPowerPin(false);
-		setResetPin(false);
-
-		client.stop();
-		Serial.println("Client disconnected");
+	// Unsupported usecase
+	if (powerButtonState == LOW && resetButtonState == LOW) {
+		previousPowerButtonState = HIGH;
+		previousResetButtonState = HIGH;
+		powerButtonPressed = false;
+		resetButtonPressed = false;
+		return;
 	}
+
+	powerButtonPressed = powerButtonState == LOW;
+	resetButtonPressed = resetButtonState == LOW;
+
+	processButtons();
 }
 
 // -----------------------------------------
 
 void processButtons()
 {
-	if (powerPressed && resetPressed) {
+	if ((powerRemotePressed && resetRemotePressed)
+	    || (powerButtonPressed && resetButtonPressed)) {
 		Serial.println("Double input..");
 		setPowerPin(false);
 		setResetPin(false);
 		return;
 	}
 
-	setPowerPin(powerPressed);
-	setResetPin(resetPressed);
+	setPowerPin(powerRemotePressed || powerButtonPressed);
+	setResetPin(resetRemotePressed || resetButtonPressed);
 }
 
 void setPowerPin(bool enable)
 {
-	powerPressed = enable;
 	// digitalWrite(POWER_GATE_PIN, (enable) ? HIGH : LOW);
 	digitalWrite(POWER_LED_PIN, (enable) ? HIGH : LOW);
 }
 
 void setResetPin(bool enable)
 {
-	resetPressed = enable;
 	// digitalWrite(RESET_GATE_PIN, (enable) ? HIGH : LOW);
 	digitalWrite(RESET_LED_PIN, (enable) ? HIGH : LOW);
 }

server/src/secrets.h.example

@@ -1,4 +1,7 @@
 #pragma once
 
-#define SSID "EXAMPLE"
-#define PASSWORD "12345678"
+#define CLIENT_MAC { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }
+#define SERVER_MAC { 0xFF, 0xFF, 0xFF, 0xFF, 0xFF, 0xFF }
+
+#define PMK "MASTERKEY1234567" // ESP_NOW_KEY_LEN = 16
+#define LMK "1234567890ABCDEF" // ESP_NOW_KEY_LEN = 16