Add secure transport and OAM router runtime implementations

- Implement secure transport mechanisms in `gateway_knx_secure_transport.cpp` for handling secure sessions, including AES encryption, session key generation, and secure packet wrapping and unwrapping.
- Introduce `OamRouterRuntime` in `oam_router_runtime.cpp` to manage OAM router identity, individual addresses, and tunnel frame handling.
- Enhance secure session management with functions for session allocation, authentication, and secure packet processing.
- Ensure compatibility with existing KNXnet/IP protocols while adding support for secure communications.

Signed-off-by: Tony <tonylu@tony-cloud.com>

components/gateway_ble/src/gateway_ble.cpp

@@ -4,6 +4,9 @@
 #include "gateway_controller.hpp"
 #include "gateway_runtime.hpp"
 
+#include "freertos/FreeRTOS.h"
+#include "freertos/task.h"
+
 #include "esp_log.h"
 #include "esp_timer.h"
 #include "host/ble_gap.h"
@@ -29,6 +32,8 @@ constexpr uint16_t kChannel2Uuid = 0xFFF2;
 constexpr uint16_t kGatewayUuid = 0xFFF3;
 constexpr int64_t kGenericDedupeWindowUs = 120000;
 constexpr size_t kGatewayCharacteristicIndex = 2;
+constexpr int kGatewayNotifyAllocationAttempts = 6;
+constexpr TickType_t kGatewayNotifyRetryDelayTicks = pdMS_TO_TICKS(20);
 
 gateway::GatewayBleBridge* s_active_bridge = nullptr;
 uint16_t s_value_handles[3] = {0, 0, 0};
@@ -348,9 +353,25 @@ void GatewayBleBridge::notifyCharacteristic(size_t index, const std::vector<uint
   }
 
   characteristic_values_[index] = payload;
-  struct os_mbuf* buffer = ble_hs_mbuf_from_flat(payload.data(), payload.size());
+  const int allocation_attempts =
+      index == kGatewayCharacteristicIndex ? kGatewayNotifyAllocationAttempts : 1;
+  struct os_mbuf* buffer = nullptr;
+  for (int attempt = 0; attempt < allocation_attempts; ++attempt) {
+    if (conn_handle_ == kInvalidConnectionHandle || !notify_enabled_[index]) {
+      return;
+    }
+    buffer = ble_hs_mbuf_from_flat(payload.data(), payload.size());
+    if (buffer != nullptr) {
+      break;
+    }
+    if (attempt + 1 < allocation_attempts) {
+      vTaskDelay(kGatewayNotifyRetryDelayTicks);
+    }
+  }
   if (buffer == nullptr) {
-    ESP_LOGW(kTag, "failed to allocate notify mbuf idx=%u", static_cast<unsigned>(index));
+    ESP_LOGW(kTag, "failed to allocate notify mbuf idx=%u attempts=%d len=%u",
+             static_cast<unsigned>(index), allocation_attempts,
+             static_cast<unsigned>(payload.size()));
     return;
   }
   const int rc = ble_gatts_notify_custom(conn_handle_, s_value_handles[index], buffer);