데이터 사용량 계산을 통신사 과금 단위에 맞춤

common.php

@@ -36,7 +36,8 @@ define('ALLOWED_IPS', array_values(array_filter(
 )));
 
 const ALLOWED_CMD = ['se', 'ef', 'en', 'hn', 'hf', 'dl', 'du', 'tu'];
-const CONTROL_CMD = ['ef', 'en', 'hn', 'hf', 'dl', 'du', 'tu'];
+const CONTROL_CMD = ['ef', 'en', 'hn', 'hf', 'dl', 'du', 'tu'];
+const CARRIER_BILLING_UNIT_BYTES = 512;
 
 const RAW_FULL_REGEX = '/(?<modem>\d{11})\/R:(?<r>[a-z])\/E:(?<E0>[io]{5}\d{3}[io])\/D:(?<D0>[oi]{7})\/L:(?<L0>o{5})\/F:(?<F0>[ots][oi]\d{4}[oi]{4})\/S:(?<S0>[^\/]+)/';
 
@@ -113,12 +114,14 @@ function db_insert_data_usage(
     ?string $requestId = null
 ): void {
     try {
+        db_ensure_data_usage_schema($pdo);
+        $carrierEstimatedBytes = carrier_billing_bytes($sentBytes + $receivedBytes);
         $stmt = $pdo->prepare("INSERT INTO car_data_usage (
             id, ts, source, cmd, sent_bytes, received_bytes, total_bytes,
-            tcp_ok, tcp_error, request_id
+            carrier_estimated_bytes, tcp_ok, tcp_error, request_id
         ) VALUES (
             'car', :ts, :source, :cmd, :sent_bytes, :received_bytes, :total_bytes,
-            :tcp_ok, :tcp_error, :request_id
+            :carrier_estimated_bytes, :tcp_ok, :tcp_error, :request_id
         )");
 
         $stmt->execute([
@@ -128,6 +131,7 @@ function db_insert_data_usage(
             ':sent_bytes' => max(0, $sentBytes),
             ':received_bytes' => max(0, $receivedBytes),
             ':total_bytes' => max(0, $sentBytes + $receivedBytes),
+            ':carrier_estimated_bytes' => $carrierEstimatedBytes,
             ':tcp_ok' => $tcpOk ? 1 : 0,
             ':tcp_error' => $tcpError !== '' ? substr($tcpError, 0, 100) : null,
             ':request_id' => $requestId,
@@ -137,6 +141,35 @@ function db_insert_data_usage(
     }
 }
 
+function carrier_billing_bytes(int $payloadBytes): int
+{
+    $payloadBytes = max(0, $payloadBytes);
+    if ($payloadBytes <= 0) {
+        return 0;
+    }
+
+    return (int)(ceil($payloadBytes / CARRIER_BILLING_UNIT_BYTES) * CARRIER_BILLING_UNIT_BYTES);
+}
+
+function db_ensure_data_usage_schema(PDO $pdo): void
+{
+    static $done = false;
+    if ($done) {
+        return;
+    }
+
+    try {
+        $stmt = $pdo->query("SHOW COLUMNS FROM car_data_usage LIKE 'carrier_estimated_bytes'");
+        if (!$stmt || !$stmt->fetch()) {
+            $pdo->exec("ALTER TABLE car_data_usage ADD COLUMN carrier_estimated_bytes INT UNSIGNED NOT NULL DEFAULT 0 AFTER total_bytes");
+        }
+    } catch (Throwable $e) {
+        // 스키마 보강 실패가 차량 제어/조회 자체를 막으면 안 된다.
+    }
+
+    $done = true;
+}
+
 function record_tcp_usage(
     string $source,
     string $cmd,