jscanner

commit 8a3b6c8d32b2dc5092e219ef16151ddafeafac63
parent e66637a019cd2581fea9d5971c25ae7cf7ec6d56
Author: Matthias Jaros <jaros@mailbox.org>
Date:   Mon, 16 Mar 2026 16:21:32 +0100

Added cli option for worker threads per host

Diffstat:
M
src/main/java/com/it_jaros/networkScanner/App.java
 | 
2
+-
M
src/main/java/com/it_jaros/networkScanner/CliParser.java
 | 
18
++++++++++++------
M
src/main/java/com/it_jaros/networkScanner/ScanOptions.java
 | 
2
+-
M
src/main/java/com/it_jaros/networkScanner/Scanner.java
 | 
6
++++--

4 files changed, 18 insertions(+), 10 deletions(-)
diff --git a/src/main/java/com/it_jaros/networkScanner/App.java b/src/main/java/com/it_jaros/networkScanner/App.java
@@ -9,7 +9,7 @@ public class App {
         try {
             ScanOptions options = cliParser.parseArgs(args);
             Scanner scanner = new Scanner(options.openSocketLimit(), options.timeoutInMillis(),
-                    options.delayInMillis());
+                    options.delayInMillis(), options.maxWorkersPerHost());
             printResults(scanner.scan(options));
         } catch (IllegalArgumentException e) {
             System.out.printf("Error while parsing arguments: %s", e.getMessage());
diff --git a/src/main/java/com/it_jaros/networkScanner/CliParser.java b/src/main/java/com/it_jaros/networkScanner/CliParser.java
@@ -14,6 +14,7 @@ public class CliParser {
         int socketLimit = 1000;
         int delayInMillis = 0;
         int timeoutInMillis = 1000;
+        int maxWorkersPerHost = 1000;
         String ports = "1-1024";
         for (int i = 0; i < args.length; i++) {
             final String currentArg = args[i];
@@ -26,6 +27,7 @@ public class CliParser {
                 switch (currentArg) {
                     case "--help", "-h":
                         usageAndExit();
+                        break;
                     case "--socketLimit", "-sl":
                         socketLimit = Integer.parseInt(args[++i]);
                         break;
@@ -38,6 +40,9 @@ public class CliParser {
                     case "--ports", "-p":
                         ports = args[++i];
                         break;
+                    case "--maxWorkersPerHost", "-wh":
+                        maxWorkersPerHost = Integer.parseInt(args[++i]);
+                        break;
                     default:
                         throw new IllegalArgumentException("No such param " + currentArg);
                 }
@@ -48,10 +53,10 @@ public class CliParser {
         }
 
         System.out.printf(
-                "Parsed arguments: targets('%s'), ports(%s), socketLimit(%s), delayInMillis(%s), timeoutInMillis(%s)\n",
-                targets, ports, socketLimit, delayInMillis, timeoutInMillis);
+                "Parsed arguments: targets('%s'), ports(%s), socketLimit(%s), delayInMillis(%s), timeoutInMillis(%s), maxWorkersPerHost(%s)%n",
+                targets, ports, socketLimit, delayInMillis, timeoutInMillis, maxWorkersPerHost);
         
-        return new ScanOptions(targets.stream().toList(), socketLimit, delayInMillis, timeoutInMillis, ports);
+        return new ScanOptions(targets.stream().toList(), socketLimit, delayInMillis, timeoutInMillis, maxWorkersPerHost, ports);
     }
 
     public void usageAndExit() {
@@ -60,10 +65,11 @@ public class CliParser {
                     java -jar scanner.jar [OPTIONS] <host>
 
                 Options:
-                    --delay, -d: Waiting period in millis for connection attempts for a host
-                    --socketLimit, -sl: Socket Connection limit for a host
-                    --timeout, -t: Timeout per connection attempt
+                    --delay, -d: Waiting period in millis for connection attempts for a host; (Default: 0)
+                    --socketLimit, -sl: Socket Connection limit for a host; (Default: 1000)
+                    --timeout, -t: Timeout per connection attempt, 0 means infinite: (Default: 1000)
                     --ports, -p: Ports to be scanned
+                    --maxWorkersPerHost, -wh: Virtual Worker Threads run per target. Higher doesn't mean necessarily faster. But the more you use the more RAM is required. (Default: 1000)
 
                 Examples:
                     java -jar scanner.jar localhost
diff --git a/src/main/java/com/it_jaros/networkScanner/ScanOptions.java b/src/main/java/com/it_jaros/networkScanner/ScanOptions.java
@@ -2,4 +2,4 @@ package com.it_jaros.networkScanner;
 
 import java.util.List;
 
-public record ScanOptions(List<String> targets, int openSocketLimit, int delayInMillis, int timeoutInMillis, String ports) {}
+public record ScanOptions(List<String> targets, int openSocketLimit, int delayInMillis, int timeoutInMillis, int maxWorkersPerHost, String ports) {}
diff --git a/src/main/java/com/it_jaros/networkScanner/Scanner.java b/src/main/java/com/it_jaros/networkScanner/Scanner.java
@@ -25,11 +25,13 @@ public class Scanner {
     private final Semaphore socketLimit;
     private final int timeoutInMillis;
     private final long delayInNanos;
+    private final int maxWorkersPerHost;
 
-    public Scanner(int socketLimit, int timeoutInMillis, int delayInMillis) {
+    public Scanner(int socketLimit, int timeoutInMillis, int delayInMillis, int maxWorkersPerHost) {
         this.timeoutInMillis = timeoutInMillis;
         this.delayInNanos = TimeUnit.MILLISECONDS.toNanos(Math.max(0, delayInMillis));
         this.socketLimit = new Semaphore(socketLimit);
+        this.maxWorkersPerHost = maxWorkersPerHost;
     }
 
     public List<ScanResult> scan(ScanOptions target) {
@@ -64,7 +66,7 @@ public class Scanner {
     private ScanResult scanTarget(String target, String ports) {
         PortRange portRange = new PortRange(ports);
         AtomicLong portSlotFactory = new AtomicLong(System.nanoTime());
-        Semaphore maxWorkers = new Semaphore(1000);
+        Semaphore maxWorkers = new Semaphore(maxWorkersPerHost);
         BitSet openPorts = new BitSet(PortRange.MAX_PORT);
 
         Progress progress = new Progress(target, portRange.getTotal(), new AtomicInteger(), new AtomicInteger());