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How to encapsulate a SCTP packet in UDP and send it over UDP channel in java

I have to transfer a file using SCTP protocol. I have written the code in java but the code is not working when I am using 4G hotspot network. So I came across this RFC which talks about UDP encapsulation of SCTP. I want to know if there is an implementation which I can use to encapsulate SCTP packet in UDP and send it over UDP channel so that it can traverse heavily NATted network. My current code for sending the data packet is as follows:
import java.io.*;
import java.net.InetSocketAddress;
import java.nio.ByteBuffer;
import java.util.*;
import com.sun.nio.sctp.MessageInfo;
import com.sun.nio.sctp.SctpChannel;
import com.sun.nio.sctp.SctpServerChannel;
public class Main {
SctpChannel connectionChannelPrimary;
SctpChannel connectionChannelSecondary;
InetSocketAddress serverSocketAddressPrimary;
InetSocketAddress serverSocketAddressSecondary;
String directoryPath;
public Main() {
serverSocketAddressPrimary = new InetSocketAddress(6002);
serverSocketAddressSecondary = new InetSocketAddress(6003);
}
public void setDirectoryPath(String directoryPath) {
this.directoryPath = directoryPath;
}
public String getDirectoryPath() {
return directoryPath;
}
public void establishConnection(int connId) throws IOException {
SctpServerChannel sctpServerChannel = SctpServerChannel.open();
if (connId == 0) {
sctpServerChannel.bind(serverSocketAddressPrimary);
connectionChannelPrimary = sctpServerChannel.accept();
System.out.println("connection established for primary");
} else {
sctpServerChannel.bind(serverSocketAddressSecondary);
connectionChannelSecondary = sctpServerChannel.accept();
System.out.println("connection established for helper");
}
}
ArrayList<String> getAllFiles() {
File directory = new File(this.directoryPath);
ArrayList<String> fileNames = new ArrayList<>();
for (File fileEntry : Objects.requireNonNull(directory.listFiles())) {
if (fileEntry.isFile()) {
fileNames.add(fileEntry.getName());
}
}
Collections.sort(fileNames);
return fileNames;
}
public byte[] readFile(String filename) throws IOException {
String extraString = "\n\n\n\nNRL\n\n\n";
File file = new File(filename);
FileInputStream fl = new FileInputStream(file);
ByteBuffer finalBuffer = ByteBuffer.allocate((int) (file.length() + extraString.length()));
byte[] arr = new byte[(int) file.length()];
int res = fl.read(arr);
if (res < 0) {
System.out.println("Error in reading file");
fl.close();
return null;
}
fl.close();
finalBuffer.put(arr);
finalBuffer.put(extraString.getBytes());
byte[] tmp = new byte[extraString.length()];
finalBuffer.position((int) (file.length() - 1));
finalBuffer.get(tmp, 0, tmp.length);
return finalBuffer.array();
}
public void sendBytes(String filename, int connId) throws IOException {
byte[] message = readFile(filename);
assert message != null;
System.out.println(message.length);
int tmp = 0;
int cntIndex = 60000;
int prevIndex = 0;
boolean isBreak = false;
while (!isBreak) {
byte[] slice;
if (prevIndex + 60000 >= message.length) {
slice = Arrays.copyOfRange(message, prevIndex, message.length);
isBreak = true;
} else {
slice = Arrays.copyOfRange(message, prevIndex, cntIndex);
prevIndex = cntIndex;
cntIndex = cntIndex + 60000;
}
final ByteBuffer byteBuffer = ByteBuffer.allocate(64000);
final MessageInfo messageInfo = MessageInfo.createOutgoing(null, 0);
byteBuffer.put(slice);
byteBuffer.flip();
tmp += slice.length;
try {
if (connId == 0) connectionChannelPrimary.send(byteBuffer, messageInfo);
else connectionChannelSecondary.send(byteBuffer, messageInfo);
} catch (Exception e) {
e.printStackTrace();
}
}
System.out.println(tmp);
}
public static void main(String[] args) throws IOException {
String bgFilePath = "/home/iiitd/Desktop/background/";
String fgFilePath = "/home/iiitd/Desktop/foreground/";
Main myObj = new Main();
myObj.setDirectoryPath("/home/iiitd/Desktop/tmp/");
myObj.establishConnection(1);
myObj.establishConnection(0);
ArrayList<String> files = myObj.getAllFiles();
for (String tmpFile : files) {
String cntFilePath = myObj.getDirectoryPath() + tmpFile;
myObj.sendBytes(cntFilePath,0);
}
}
}
RFC Link: https://datatracker.ietf.org/doc/html/draft-ietf-tsvwg-sctp-udp-encaps-09

In C, I think that usrsctp is a popular implementation of SCTP over UDP. If I understand correctly, it was used by Google Chrome at some point (though I see they mentioned moving to "dcsctp" at some point). Also I have seen it in a mirror of the Firefox sources in 2016, not sure what's the state today.
So one solution would be to wrap usrsctp with JNI. And it appears that this is exactly what jitsi-sctp is doing. I haven't used it, but I would have a look.

Read rcon command response

I want to send rcon command to server using java, to do this I'm using the following library https://github.com/Kronos666/rkon-core
When i run command like this
Rcon rcon = new Rcon("127.0.0.1", 27015, "mypassword".getBytes());
// Example: On a minecraft server this will list the connected players
String result = rcon.command("list");
// Display the result in the console
System.out.println(result);
My server show response in console Gc connection established from... and so on
but in java app i have the empty result, it's not null, it's just empty
String result = rcon.command("list");
How can i take response from server using rcon protocol?

Try this:
try {
Rcon rcon = new Rcon("127.0.0.1", 27015, "mypassword".getBytes());
String result = rcon.command("list");
System.out.println(result);
} catch (AuthenticationException e) {
String result = "Authentication failed";
}

Finally I write my own implementation:
public final class RconClient implements AutoCloseable {
private static final int MAX_SIZE = 4096;
private final Socket socket;
private final RconData data;
private static final Logger LOG = LoggerFactory.getLogger(RconClient.class);
#SuppressWarnings("ConstructorShouldNotThrowExceptions")
public RconClient(final String host,
final int port,
final byte[] password) throws IOException {
this.socket = new Socket(host, port);
final RconData requst = request(new RconData(RconData.AUTH, password));
if (requst.getId() == -1) {
LOG.error("Wrong password or ip to connect to rcon");
throw new LoginException(host, port);
}
this.data = read();
}
public String command(String command) throws IOException {
command = "get5_status";
final RconData response = request(new RconData(command.getBytes()));
return new String(response.getPayload(), Charset.forName("UTF-8"));
}
public RconData request(RconData packet) throws IOException {
try {
write(packet);
return read();
} catch (final SocketException exception) {
socket.close();
throw exception;
}
}
private void write(RconData packet) throws IOException {
ByteBuffer buffer = ByteBuffer.allocate(packet.getPayload().length + 14);
buffer.order(ByteOrder.LITTLE_ENDIAN);
buffer.putInt(packet.getPayload().length + 10);
buffer.putInt(packet.getId());
buffer.putInt(packet.getType());
buffer.put(packet.getPayload());
buffer.put((byte)0);
buffer.put((byte)0);
socket.getOutputStream().write(buffer.array());
socket.getOutputStream().flush();
}
private RconData read() throws IOException {
byte[] packet = new byte[MAX_SIZE];
int packetSize = this.socket.getInputStream().read(packet);
ByteBuffer buffer = ByteBuffer.wrap(packet, 0, packetSize);
buffer.order(ByteOrder.LITTLE_ENDIAN);
if (buffer.remaining() < 4) {
throw new WrongPacketException();
}
int size = buffer.getInt();
if (buffer.remaining() < size) {
throw new WrongPacketException();
}
int id = buffer.getInt();
int type = buffer.getInt();
byte[] payload = new byte[size - 10];
buffer.get(payload);
buffer.get(new byte[2]);
return new RconData(id, type, payload);
}
#Override
public void close() throws IOException {
this.socket.close();
}
}
Where RconData it's simple POJO with byte[] password property,

Java integration with SSRS

Hi I am looking into using Java (to be deployed as servlets in Websphere 8.5) to integrate with SSRS. I have looked into some of the sample codes out there and try it out.
private static SoapHeader createExecutionIdSoapHeader(String executionId) {
Document doc = DOMUtils.createDocument();
Element executionHeaderElement = doc.createElement("ExecutionHeader");
executionHeaderElement.setAttribute("xmlns", XML_NAMESPACE);
Element executionIdElement = doc.createElement("ExecutionID");
executionIdElement.setTextContent(executionId);
executionHeaderElement.appendChild(executionIdElement);
SoapHeader soapH = new SoapHeader(new QName(XML_NAMESPACE, "ExecutionHeader"), executionHeaderElement);
return soapH;
}
public static Holder<byte[]> getReportResult(String output_type, String reportFolder, String reportName, ArrayOfParameterValue arrayOfParameterValue) {
Holder<byte[]> result = null;
try {
String historyID = null;
String executionID = null;
ReportExecutionServiceSoap service = getExecutionService();
BindingProvider bp = (BindingProvider) service;
bp.getRequestContext().put(BindingProvider.USERNAME_PROPERTY, authenticator.getUsername());
bp.getRequestContext().put(BindingProvider.PASSWORD_PROPERTY, authenticator.getPassword());
ExecutionInfo info = new ExecutionInfo();
info = service.loadReport(REPORT_PATH, historyID);
executionID = info.getExecutionID();
List<Header> headers = new ArrayList<Header>();
SoapHeader header = createExecutionIdSoapHeader(executionID);
headers.add(header);
bp.getRequestContext().put(Header.HEADER_LIST, headers);
if (!arrayOfParameterValue.getParameterValue().isEmpty()) {
service.setExecutionParameters(arrayOfParameterValue, "en-us");
}
// Default to return HTML4.0
String deviceInfo = "";
if (output_type == null || output_type.isEmpty()) {
output_type = "HTML4.0";
}
if ("IMAGE".equalsIgnoreCase(output_type)) {
deviceInfo = RENDER_DEVICE_INFO_IMAGE;
} else {
deviceInfo = RENDER_DEVICE_INFO_HTML;
}
result = new Holder<byte[]>();
Holder<String> extension = new Holder<String>();
Holder<String> mimeType = new Holder<String>();
Holder<String> encoding = new Holder<String>();
Holder<ArrayOfWarning> warnings = new Holder<ArrayOfWarning>();
Holder<ArrayOfString> streamIDs = new Holder<ArrayOfString>();
service.render(output_type, deviceInfo, result, extension, mimeType, encoding, warnings, streamIDs);
} catch (Throwable th) {
th.printStackTrace();
}
return result;
}
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
try {
ArrayOfParameterValue arrayOfParameterValue = new ArrayOfParameterValue();
List<ParameterValue> parameters = arrayOfParameterValue.getParameterValue();
ParameterValue parameterValue = new ParameterValue();
parameterValue.setName(PARAMETER_NAME);
parameterValue.setValue(PARAMETER_VALUE);
parameters.add(parameterValue);
Holder<byte[]> result = GenerateReport.getReportResult(REPORT_FORMAT, REPORT_FOLDER, REPORT_NAME,
arrayOfParameterValue);
System.out.println("--------------------------------- Writing to Browser --------------------------------");
ServletOutputStream out = response.getOutputStream();
out.write(result.value);
out.flush();
out.close();
System.out.println("--------------------------------- Writing to File -----------------------------------");
DateFormat df = new SimpleDateFormat("dd_MM_yy_HH_mm_ss_");
Date date = new Date();
String filename = df.format(date) + "SSRS_Report.pdf";
FileOutputStream o = new FileOutputStream("C:\\Users\\keh\\Desktop\\Temp\\" + filename);
o.write(result.value);
o.flush();
o.close();
} catch (Exception e) {
e.printStackTrace();
}
}
When I run the codes, I have this error :
[5/17/17 19:21:02:704 SGT] 000000c4 SystemErr R javax.xml.ws.soap.SOAPFaultException: The session identifier is missing. A session identifier is required for this operation. ---> Microsoft.ReportingServices.Diagnostics.Utilities.MissingSessionIdException: The session identifier is missing. A session identifier is required for this operation.
Any expert out there can point me to a solution pls?
P.S. I have tried to use WSBindingProvider as shown in Surendra Gurjar's Blog and it ran beautifully on an Apache server, but I got a ClassCastException when I deploy it to Websphere.

Spring boot Birt Report with Angular 2 client Generates Corrupt PDF File

I am trying to configure birt report in a spring boot applications, the client is an angular 2 application, here is where I run the report:
#PostConstruct
public void startUp() {
if(inputDir == null)
throw new RuntimeException("Cannot start application since birt report input directory was not specified.");
try {
EngineConfig engineConfig = new EngineConfig();
engineConfig.getAppContext().put("spring", this.context);
RegistryProviderFactory.releaseDefault();
Platform.startup(engineConfig);
IReportEngineFactory reportEngineFactory = (IReportEngineFactory) Platform.createFactoryObject(IReportEngineFactory.EXTENSION_REPORT_ENGINE_FACTORY);
birtReportEngine = reportEngineFactory.createReportEngine(engineConfig);
} catch (BirtException e) {
}
reportOutputDirectory = env.getProperty("birt_temp_file_output_dir");
}
#Override
public ByteArrayOutputStream runReport(Report birtReport) {
ByteArrayOutputStream byteArrayOutputStream;
File rptDesignFile;
try {
rptDesignFile = getReportFromFilesystem(birtReport.getName());
} catch (Exception e) {
throw new RuntimeException("Could not find report");
}
Map<String, String> parsedParameters = parseParametersAsMap(birtReport.getParameters());
byteArrayOutputStream = new ByteArrayOutputStream();
try {
IReportRunnable reportDesign = birtReportEngine.openReportDesign(rptDesignFile.getPath());
IRunTask runTask = birtReportEngine.createRunTask(reportDesign);
if (parsedParameters.size() > 0) {
for (Map.Entry<String, String> entry : parsedParameters.entrySet()) {
runTask.setParameterValue(entry.getKey(), entry.getValue());
}
}
runTask.validateParameters();
String rptdocument = reportOutputDirectory + File.separator
+ "generated" + File.separator
+ birtReport.getName() + ".rptdocument";
runTask.run(rptdocument);
IReportDocument reportDocument = birtReportEngine.openReportDocument(rptdocument);
IRenderTask renderTask = birtReportEngine.createRenderTask(reportDocument);
PDFRenderOption pdfRenderOption = new PDFRenderOption();
pdfRenderOption.setOption(IPDFRenderOption.REPAGINATE_FOR_PDF, new Boolean(true));
pdfRenderOption.setOption(IPDFRenderOption.PAGE_OVERFLOW, IPDFRenderOption.OUTPUT_TO_MULTIPLE_PAGES );
pdfRenderOption.setOption(IPDFRenderOption.PDF_TEXT_WRAPPING , true);
pdfRenderOption.setOption(IPDFRenderOption.PDF_HYPHENATION , true);
pdfRenderOption.setOutputFormat("pdf");
pdfRenderOption.setOutputStream(byteArrayOutputStream);
renderTask.setRenderOption(pdfRenderOption);
renderTask.render();
renderTask.close();
} catch (EngineException e) {
throw new RuntimeException();
}
return byteArrayOutputStream;
}
and this is the api service that returns the byte array:
#RequestMapping(value = "/birt", method = RequestMethod.POST)
public ResponseEntity<byte[]> getBIRTReport(#RequestBody ReportRequest reportRequest) {
byte[] reportBytes;
ResponseEntity<byte[]> responseEntity;
try {
reportBytes =
new BIRTReport(
reportRequest.getReportName(),
reportRequest.getReportParameters(),
reportRunner)
.runReport().getReportContent().toByteArray();
HttpHeaders httpHeaders = new HttpHeaders();
httpHeaders.setContentType(MediaType.parseMediaType("application/pdf"));
String fileName = reportRequest.getReportName() + ".pdf";
httpHeaders.setContentDispositionFormData(fileName, fileName);
httpHeaders.setCacheControl("must-revalidate, post-check=0, pre-check=0");
responseEntity = new ResponseEntity<byte[]>(reportBytes, httpHeaders, HttpStatus.OK);
} catch (Exception e) {
responseEntity = new ResponseEntity<byte[]>(HttpStatus.NOT_IMPLEMENTED);
return responseEntity;
}
return responseEntity;
}
and that is the angular 2 code:
public getReport():Observable<any>{
let params = {
"reportName":"my report name",
"reportParameters":"my params"
};
let headers = new Headers();
headers.append('Content-Type','application/json');
let options = new RequestOptions({headers: headers});
return this.http.post("http://localhost:8080/reports/birt",JSON.stringify(params), options);
}
call the service:
getReport(){
this.reportService.getReport().subscribe(
data => {
var blob = new Blob([data._body], { type: 'application/pdf'})
saveAs(blob, "myPdf.pdf");
var fileUrl = URL.createObjectURL(blob);
window.open(fileUrl);
}
)
}
This method returns a corrupt file, can anyone figure out the problem?

The problem is that you are missing responseType in options
let options = new RequestOptions({headers: headers, **responseType: ResponseContentType.Blob**});
After that you can just do
window['saveAs'](response.blob(), 'filename.zip');

Java - ReadObject with nio

In a traditional blocking-thread server, I would do something like this
class ServerSideThread {
ObjectInputStream in;
ObjectOutputStream out;
Engine engine;
public ServerSideThread(Socket socket, Engine engine) {
in = new ObjectInputStream(socket.getInputStream());
out = new ObjectOutputStream(socket.getOutputStream());
this.engine = engine;
}
public void sendMessage(Message m) {
out.writeObject(m);
}
public void run() {
while(true) {
Message m = (Message)in.readObject();
engine.queueMessage(m,this); // give the engine a message with this as a callback
}
}
}
Now, the object can be expected to be quite large. In my nio loop, I can't simply wait for the object to come through, all my other connections (with much smaller workloads) will be waiting on me.
How can I only get notified that a connection has the entire object before it tells my nio channel it's ready?

You can write the object to a ByteArrayOutputStream allowing you to give the length before an object sent. On the receiving side, read the amount of data required before attempting to decode it.
However, you are likely to find it much simpler and more efficient to use blocking IO (rather than NIO) with Object*Stream
Edit something like this
public static void send(SocketChannel socket, Serializable serializable) throws IOException {
ByteArrayOutputStream baos = new ByteArrayOutputStream();
for(int i=0;i<4;i++) baos.write(0);
ObjectOutputStream oos = new ObjectOutputStream(baos);
oos.writeObject(serializable);
oos.close();
final ByteBuffer wrap = ByteBuffer.wrap(baos.toByteArray());
wrap.putInt(0, baos.size()-4);
socket.write(wrap);
}
private final ByteBuffer lengthByteBuffer = ByteBuffer.wrap(new byte[4]);
private ByteBuffer dataByteBuffer = null;
private boolean readLength = true;
public Serializable recv(SocketChannel socket) throws IOException, ClassNotFoundException {
if (readLength) {
socket.read(lengthByteBuffer);
if (lengthByteBuffer.remaining() == 0) {
readLength = false;
dataByteBuffer = ByteBuffer.allocate(lengthByteBuffer.getInt(0));
lengthByteBuffer.clear();
}
} else {
socket.read(dataByteBuffer);
if (dataByteBuffer.remaining() == 0) {
ObjectInputStream ois = new ObjectInputStream(new ByteArrayInputStream(dataByteBuffer.array()));
final Serializable ret = (Serializable) ois.readObject();
// clean up
dataByteBuffer = null;
readLength = true;
return ret;
}
}
return null;
}

Inspired by the code above I've created a (GoogleCode project)
It includes a simple unit test:
SeriServer server = new SeriServer(6001, nthreads);
final SeriClient client[] = new SeriClient[nclients];
//write the data with multiple threads to flood the server
for (int cnt = 0; cnt < nclients; cnt++) {
final int counterVal = cnt;
client[cnt] = new SeriClient("localhost", 6001);
Thread t = new Thread(new Runnable() {
public void run() {
try {
for (int cnt2 = 0; cnt2 < nsends; cnt2++) {
String msg = "[" + counterVal + "]";
client[counterVal].send(msg);
}
} catch (IOException e) {
e.printStackTrace();
fail();
}
}
});
t.start();
}
HashMap<String, Integer> counts = new HashMap<String, Integer>();
int nullCounts = 0;
for (int cnt = 0; cnt < nsends * nclients;) {
//read the data from a vector (that the server pool automatically fills
SeriDataPackage data = server.read();
if (data == null) {
nullCounts++;
System.out.println("NULL");
continue;
}
if (counts.containsKey(data.getObject())) {
Integer c = counts.get(data.getObject());
counts.put((String) data.getObject(), c + 1);
} else {
counts.put((String) data.getObject(), 1);
}
cnt++;
System.out.println("Received: " + data.getObject());
}
// asserts the results
Collection<Integer> values = counts.values();
for (Integer value : values) {
int ivalue = value;
assertEquals(nsends, ivalue);
System.out.println(value);
}
assertEquals(counts.size(), nclients);
System.out.println(counts.size());
System.out.println("Finishing");
server.shutdown();