Refactor VPN proxy client implementation

src/server/gatewayRouting.ts

@@ -0,0 +1,23 @@
+import { spawnSync } from 'node:child_process';
+
+const options = { encoding: 'utf8' as const };
+
+export function setGatewayInterception(enabled: boolean, chain: string, run: typeof spawnSync = spawnSync) {
+  const rule = ['-w', '-t', 'mangle', 'PREROUTING', '-j', chain];
+  const exists = run('iptables', [...rule.slice(0, 3), '-C', ...rule.slice(3)], options).status === 0;
+
+  if (!enabled) {
+    if (exists) run('iptables', [...rule.slice(0, 3), '-D', ...rule.slice(3)], options);
+    return;
+  }
+  if (exists) return;
+
+  const result = run(
+    'iptables',
+    [...rule.slice(0, 3), '-I', 'PREROUTING', '1', '-j', chain],
+    options,
+  );
+  if (result.status !== 0) {
+    throw new Error((result.stderr || 'Не удалось включить Gateway VPN').trim());
+  }
+}