From 420db0fcdf8c559378e239c7643ee22d0a23ec1e Mon Sep 17 00:00:00 2001
From: eddy <eddy@macmini.local>
Date: Tue, 4 Aug 2026 22:12:48 +0200
Subject: [PATCH] feat(client): report UUID and version to server after ECDH
 handshake

---
 src/client.cpp | 53 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 53 insertions(+)

diff --git a/src/client.cpp b/src/client.cpp
index 15746fc..3c0dbf2 100644
--- a/src/client.cpp
+++ b/src/client.cpp
@@ -37,7 +37,13 @@ CRGB leds[NUM_LEDS];
 #define CHARACTERISTIC_UUID "beb5483e-36e1-4688-b7f5-ea07361f26d8"
 #define UUID_CHAR_UUID      "beb5483e-36e1-4688-b7f5-ea07361f26d9"
 #define ECDH_UUID           "beb5483e-36e1-4688-b7f5-ea07361f26dc"
+#define CLIENT_REGISTRY_UUID "beb5483e-36e1-4688-b7f5-ea07361f26dd"
+#define CLIENT_CONTROL_UUID  "beb5483e-36e1-4688-b7f5-ea07361f26de"
 #define ESP_UUID_LEN  16
+#define BROKER_PLAIN_SIZE  20
+#define BROKER_PKT_SIZE    (4 + 8 + BROKER_PLAIN_SIZE + 16)
+#define BROKER_CMD_UPDATE_AVAILABLE  0x10
+#define BROKER_CMD_CLIENT_READY      0x20
 #define NVS_NAMESPACE "syl"
 #define NVS_PSK_NAME  "psk"
 #define NVS_UUID_NAME "uuid"
@@ -321,6 +327,53 @@ static bool connectToServer() {
     relay1SendState = false;
     relay2SendState = false;
     ESP_LOGI(TAG, "BLE: server UUID verified, ECDH done, ready");
+
+    NimBLERemoteCharacteristic *pRegChar = pSvc->getCharacteristic(CLIENT_REGISTRY_UUID);
+    if (pRegChar == nullptr) {
+        ESP_LOGW(TAG, "BLE: CLIENT_REGISTRY characteristic not found");
+    } else {
+        uint8_t plainPayload[BROKER_PLAIN_SIZE];
+        memset(plainPayload, 0, BROKER_PLAIN_SIZE);
+        plainPayload[0] = 0x00;
+        memcpy(plainPayload + 1, deviceUuid, ESP_UUID_LEN);
+        uint16_t clientVersion = (uint16_t)atoi(FIRMWARE_VERSION_CLIENT);
+        plainPayload[1 + ESP_UUID_LEN] = (clientVersion >> 8) & 0xFF;
+        plainPayload[1 + ESP_UUID_LEN + 1] = clientVersion & 0xFF;
+
+        uint8_t pkt[BROKER_PKT_SIZE];
+        memset(pkt, 0, BROKER_PKT_SIZE);
+        uint32_t s = ++seq;
+        pkt[0] = (s >> 24) & 0xFF;
+        pkt[1] = (s >> 16) & 0xFF;
+        pkt[2] = (s >> 8)  & 0xFF;
+        pkt[3] = s & 0xFF;
+
+        for (int i = 0; i < 8; i++) pkt[4 + i] = (uint8_t)(esp_random() & 0xFF);
+
+        uint8_t nonce[12];
+        memcpy(nonce, pkt, 4);
+        memcpy(nonce + 4, pkt + 4, 8);
+
+        mbedtls_gcm_context gcm;
+        mbedtls_gcm_init(&gcm);
+        int ret = mbedtls_gcm_setkey(&gcm, MBEDTLS_CIPHER_ID_AES, aesKey, AES_KEY_LEN * 8);
+        if (ret != 0) {
+            ESP_LOGE(TAG, "REGISTRY: setkey failed (ret=%d)", ret);
+            mbedtls_gcm_free(&gcm);
+        } else {
+            mbedtls_gcm_crypt_and_tag(&gcm, MBEDTLS_GCM_ENCRYPT,
+                BROKER_PLAIN_SIZE, nonce, 12, NULL, 0,
+                plainPayload, pkt + 12, 16, pkt + 12 + BROKER_PLAIN_SIZE);
+            mbedtls_gcm_free(&gcm);
+
+            if (pRegChar->writeValue(pkt, BROKER_PKT_SIZE, false)) {
+                ESP_LOGI(TAG, "REGISTRY: reported uuid + version %d to server", FIRMWARE_VERSION_CLIENT);
+            } else {
+                ESP_LOGW(TAG, "REGISTRY: write failed");
+            }
+        }
+    }
+
     return true;
 }