[cleanup] general bug fix and code cleanup

1. support windows .bat when executing
2. improve shared library loading
2. use memorySegment asSlice for ByteArray#sub
3. fix ipv4 copy
4. modify length in udp packet
5. remove unused classes

base/src/main/java/io/vproxy/base/util/Utils.java

@@ -563,13 +563,18 @@ public static ExecuteResult execute(String script, int timeout, boolean getResul
         } else {
             Logger.alert("trying to execute script: " + script);
         }
-        File file = File.createTempFile("script", ".sh");
+        File file = File.createTempFile("script", OS.isWindows() ? ".bat" : ".sh");
         try {
             Files.writeString(file.toPath(), script);
             if (!file.setExecutable(true)) {
                 throw new Exception("setting executable to script " + file.getAbsolutePath() + " failed");
             }
-            ProcessBuilder pb = new ProcessBuilder(file.getAbsolutePath());
+            ProcessBuilder pb;
+            if (OS.isWindows()) {
+                pb = new ProcessBuilder("cmd.exe", "/c", file.getAbsolutePath());
+            } else {
+                pb = new ProcessBuilder(file.getAbsolutePath());
+            }
             return execute(pb, timeout, getResult);
         } finally {
             //noinspection ResultOfMethodCallIgnored
@@ -951,6 +956,17 @@ public static List<Nic> getNetworkInterfaces() throws IOException {
     }
 
     public static void loadDynamicLibrary(String name) throws UnsatisfiedLinkError {
+        loadDynamicLibrary(name, Utils.class.getClassLoader(), "io/vproxy/");
+    }
+
+    public static void loadDynamicLibrary(String name, ClassLoader cl, String basePath) throws UnsatisfiedLinkError {
+        // format basePath
+        if (basePath.startsWith("/")) {
+            basePath = basePath.substring(1);
+        }
+        if (!basePath.endsWith("/")) {
+            basePath += "/";
+        }
         // check and use bundled binaries
         String filename = "lib" + name + "-" + OS.arch();
         String suffix;
@@ -963,7 +979,7 @@ public static void loadDynamicLibrary(String name) throws UnsatisfiedLinkError {
             suffix = ".so";
         }
 
-        InputStream is = Utils.class.getClassLoader().getResourceAsStream("io/vproxy/" + filename + suffix);
+        InputStream is = cl.getResourceAsStream(basePath + filename + suffix);
         if (is == null) {
             System.out.println("System.loadLibrary(" + name + ")");
             System.loadLibrary(name);

base/src/main/java/io/vproxy/base/util/bytearray/MemorySegmentByteArray.java

@@ -14,6 +14,10 @@ public MemorySegmentByteArray(MemorySegment seg) {
         this.seg = seg;
     }
 
+    public MemorySegment getMemorySegment() {
+        return seg;
+    }
+
     @Override
     public byte get(int idx) {
         return seg.get(ValueLayout.JAVA_BYTE, idx);
@@ -138,4 +142,10 @@ public ByteArray int64ReverseNetworkByteOrder(int offset, long val) {
         seg.set(LONG_LITTLE_ENDIAN, offset, val);
         return this;
     }
+
+    @Override
+    public ByteArray sub(int fromInclusive, int len) {
+        var newSeg = seg.asSlice(fromInclusive, len);
+        return new MemorySegmentByteArray(newSeg);
+    }
 }

base/src/main/java/io/vproxy/vfd/ReadableByteStream.java

@@ -6,7 +6,7 @@
 public interface ReadableByteStream {
     int read(ByteBuffer dst) throws IOException;
 
-    default int readBlocking(ByteBuffer buf) throws IOException {
-        return read(buf);
+    default int readBlocking(ByteBuffer dst) throws IOException {
+        return read(dst);
     }
 }

base/src/main/java/io/vproxy/vpacket/Ipv4Packet.java

@@ -258,7 +258,7 @@ public Ipv4Packet copy() {
         ret.options = options;
         ret.packet = packet.copy();
         ret.packet.recordParent(ret);
-        return this;
+        return ret;
     }
 
     @Override

base/src/main/java/io/vproxy/vpacket/UdpPacket.java

@@ -235,6 +235,12 @@ public void setData(AbstractPacket data) {
         this.data = data;
     }
 
+    public void setData(ByteArray data) {
+        clearRawPacket();
+        this.data = new PacketBytes(data);
+        this.length = data.length() + 8;
+    }
+
     @Override
     public void clearAllRawPackets() {
         clearRawPacket();