From ac649d2b2f84923da29ea5ce14ee0247086dc33d Mon Sep 17 00:00:00 2001
From: Matthias Jaros <jarlucmat@mailbox.org>
Date: Sun, 30 Aug 2026 22:25:48 +0200
Subject: Fix bug wrong primitive used for recv method that needs long instead
 of int

---
 src/main/java/com/it_jaros/jns/scan/ExceptionInfo.java         |  2 ++
 .../java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java     |  2 +-
 .../jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java      | 10 +++++-----
 3 files changed, 8 insertions(+), 6 deletions(-)

(limited to 'src/main/java/com/it_jaros')

diff --git a/src/main/java/com/it_jaros/jns/scan/ExceptionInfo.java b/src/main/java/com/it_jaros/jns/scan/ExceptionInfo.java
index cdbf741..417ea23 100644
--- a/src/main/java/com/it_jaros/jns/scan/ExceptionInfo.java
+++ b/src/main/java/com/it_jaros/jns/scan/ExceptionInfo.java
@@ -10,6 +10,8 @@ public record ExceptionInfo(
             return ExceptionInfo.from(cause);
         }
 
+        // for debugging only
+        //t.printStackTrace();
         return new ExceptionInfo(
                 t.getClass().getName(),
                 t.getMessage()
diff --git a/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java b/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java
index 21b93f8..0c1b9e0 100644
--- a/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java
+++ b/src/main/java/com/it_jaros/jns/scan/engine/ScanUdpPortTask.java
@@ -81,7 +81,7 @@ public class ScanUdpPortTask implements Callable<PortResult> {
 
                 MemorySegment recvBuffer = arena.allocate(RECV_BUFFER_SIZE);
                 try {
-                    int bytesRead = linuxUdpSocketAPI.recv(fd, recvBuffer);
+                    long bytesRead = linuxUdpSocketAPI.recv(fd, recvBuffer);
                     if (bytesRead >= 0) {
                         return PortState.OPEN;
                     }
diff --git a/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java b/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java
index fe087d7..bbd2009 100644
--- a/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java
+++ b/src/main/java/com/it_jaros/jns/scan/engine/platform/linux/LinuxUdpSocketAPI.java
@@ -15,7 +15,6 @@ public class LinuxUdpSocketAPI {
     public static final int AF_INET6 = 10;
     public static final int EAGAIN = 11;
     public static final int ECONNREFUSED = 111;
-    public static final int EWOULDBLOCK = 11;
     public static final int SOCK_DGRAM = 2;
     public static final int SOL_SOCKET = 1;
     public static final int SO_RCVTIMEO = 20;
@@ -117,7 +116,7 @@ public class LinuxUdpSocketAPI {
         System.arraycopy(argv, 0, newArgv, 1, argv.length);
         try {
             final T rc = callNativeMethod(methodHandle, newArgv);
-            if (rc.intValue() < 0) {
+            if (rc.longValue() < 0) {
                 throw new RawLinuxSocketException(methodHandle.toString(), errno(state));
             }
             return rc;
@@ -144,11 +143,12 @@ public class LinuxUdpSocketAPI {
     }
 
     public void sendEmptyDatagram(int fd) throws IOException {
-        wrapNativeMethodCall(SEND, fd, MemorySegment.NULL, 0L, 0);
+        MemorySegment buffer = arena.allocate(1L);
+        wrapNativeMethodCall(SEND, fd, buffer, buffer.byteSize(), 0);
     }
 
-    public int recv(int fd, MemorySegment buffer) throws IOException {
-        return wrapNativeMethodCall(RECV, fd, buffer, (int) buffer.byteSize(), 0);
+    public long recv(int fd, MemorySegment buffer) throws IOException {
+        return wrapNativeMethodCall(RECV, fd, buffer, buffer.byteSize(), 0);
     }
 
     public void setReceiveTimeout(int fd, long timeoutInMillis) throws IOException {
-- 
cgit v1.3.1-4-g156e