From f42cfda65a035a8708baf36b9c212d8b8e33516a Mon Sep 17 00:00:00 2001
From: Matthias Jaros <jarlucmat@mailbox.org>
Date: Thu, 22 Jan 2026 21:05:16 +0100
Subject: Working version with semaphore counter and rate limiter

---
 src/main/java/com/it_jaros/networkScanner/App.java | 41 ++++++++++++++++++++++
 1 file changed, 41 insertions(+)
 create mode 100644 src/main/java/com/it_jaros/networkScanner/App.java

(limited to 'src/main/java/com/it_jaros/networkScanner/App.java')

diff --git a/src/main/java/com/it_jaros/networkScanner/App.java b/src/main/java/com/it_jaros/networkScanner/App.java
new file mode 100644
index 0000000..5d52065
--- /dev/null
+++ b/src/main/java/com/it_jaros/networkScanner/App.java
@@ -0,0 +1,41 @@
+package com.it_jaros.networkScanner;
+
+import java.util.List;
+
+public class App {
+    public static void main(String[] args) {
+        Scanner scanner = new Scanner();
+        if (args.length < 1 || args[0] == "") {
+            usageAndExit();
+        }
+        String target = args[0];
+        System.out.printf(
+                "Scanning host=%s \n",
+                target);
+
+        try (FdCounter fd = new FdCounter()) {
+            fd.start(20); // sample every 20ms
+            List<Integer> openPorts = scanner.scanPorts(target, 10000);
+            printPorts(target, openPorts);
+            System.out.println("FD limit: " + fd.maxFds());
+            System.out.println("Peak open FDs during scan: " + fd.peakOpenFds());
+        }
+    }
+
+    public static void printPorts(String address, List<Integer> openPorts) {
+        System.out.println("Address:" + address);
+        openPorts.forEach((p) -> System.out.println("Open port: " + p));
+    }
+
+    private static void usageAndExit() {
+        System.err.println("""
+            Usage:
+              java -jar scanner.jar <host> 
+
+            Examples:
+              java -jar scanner.jar localhost
+              java -jar scanner.jar fd00::1 
+            """);
+        System.exit(1);
+    }
+}
-- 
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