jscanner

commit 816c93e021efba3b3db49bbfbff0c2ae224426a1
parent ea9dc4aeaa722ab2e95cfb57f35e319ee983927b
Author: Matthias Jaros <jaros@mailbox.org>
Date:   Fri, 23 Jan 2026 22:39:39 +0100

Added support for delayInMillis in between connection attempts

Diffstat:
M
src/main/java/com/it_jaros/networkScanner/CliParser.java
 | 
3
+--
M
src/main/java/com/it_jaros/networkScanner/ScanTarget.java
 | 
2
+-
M
src/main/java/com/it_jaros/networkScanner/Scanner.java
 | 
19
++++++++++++-------

3 files changed, 14 insertions(+), 10 deletions(-)
diff --git a/src/main/java/com/it_jaros/networkScanner/CliParser.java b/src/main/java/com/it_jaros/networkScanner/CliParser.java
@@ -7,12 +7,11 @@ public class CliParser {
             throw new IllegalArgumentException("No argument given");
         }
         
-        String currentArg;
         String target = null;
         int socketLimit = 1000;
         int delayInMillis = 0;
         for (int i = 0; i < args.length; i++) {
-            currentArg = args[i];
+            final String currentArg = args[i];
             if (!currentArg.startsWith("-")) {
                 target = currentArg;
                 continue;
diff --git a/src/main/java/com/it_jaros/networkScanner/ScanTarget.java b/src/main/java/com/it_jaros/networkScanner/ScanTarget.java
@@ -1,3 +1,3 @@
 package com.it_jaros.networkScanner;
 
-public record ScanTarget(String address, int openSocketLimit, int delay) {}
+public record ScanTarget(String address, int openSocketLimit, int delayInMillis) {}
diff --git a/src/main/java/com/it_jaros/networkScanner/Scanner.java b/src/main/java/com/it_jaros/networkScanner/Scanner.java
@@ -10,30 +10,35 @@ import java.util.concurrent.ConcurrentLinkedQueue;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.Semaphore;
+import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicLong;
+import java.util.concurrent.locks.LockSupport;
 
 public class Scanner {
                 
     private Counter counter = new Counter();
-    private final int socketLimitDefault = 1024;
     
     public Scanner() {}
 
     public List<Integer> scanPorts(ScanTarget
      target) {
-        return scanPorts(target.address(), target.openSocketLimit());
-    }
-    
-    public List<Integer> scanPorts(String address) {
-        return scanPorts(address, socketLimitDefault);
+        return scanPorts(target.address(), target.openSocketLimit(), target.delayInMillis());
     }
 
-    public List<Integer> scanPorts(String address, int socketLimit) {
+    public List<Integer> scanPorts(String address, int socketLimit, int delayInMillis) {
         Queue<Integer> openPorts = new ConcurrentLinkedQueue<>();
         Semaphore socketCap = new Semaphore(socketLimit);
+        long delayInNanos = TimeUnit.MILLISECONDS.toNanos(Math.max(0, delayInMillis));
+        AtomicLong nextStartNanos = new AtomicLong(System.nanoTime());
         try (ExecutorService executor = Executors.newVirtualThreadPerTaskExecutor()) {
             for (int port = 1; port < 65536; port++) {
                 final int currentPort = port;
                 executor.submit(() -> {
+                    if (delayInNanos > 0) {
+                        long mySlot = nextStartNanos.getAndAdd(delayInNanos);
+                        long wait = mySlot - System.nanoTime();
+                        if (wait > 0) LockSupport.parkNanos(wait);
+                    }
                     socketCap.acquireUninterruptibly();
                     counter.inc();
                     try (Socket socket = new Socket()) {