/// <summary>
/// Creates a message and all it's fragments. From a file.
/// </summary>
/// <param name="remoteEndPoint">Where to send the message</param>
/// <param name="file">File to send</param>
/// <param name="maxFragmentSize">Maximum size of one fragment in bytes</param>
public static Message CreateFileMessage(IPEndPoint remoteEndPoint, string file, ushort maxFragmentSize)
{
// read file bytes
var fileBytes = File.ReadAllBytes(file);
// create a sorted list of fragments
var fragmentList = new SortedList<ushort, byte[]>();
// add all fragments
while (fileBytes.Length > 0) {
// get the fragment bytes
byte[] bytes;
// check the remaining size
if (fileBytes.Length > maxFragmentSize) {
// take maximum allowed bytes and make a fragment
bytes = fileBytes.Take(maxFragmentSize).ToArray();
// shift
fileBytes = fileBytes.Skip(maxFragmentSize).ToArray();
}
else {
// take whole fragment
bytes = fileBytes;
fileBytes = new byte[0];
}
// add the fragment to the list
fragmentList.Add((ushort) fragmentList.Count, bytes);
}
// create a message
var message = new Message((ushort) fragmentList.Count, fragmentList) {
RemoteEndPoint = remoteEndPoint,
FileName = Path.GetFileName(file)
};
// return the message
return message;
}
/// <summary>
/// Sends a fragment.
/// </summary>
private Task SendFragment(Message message, byte[] fragment, FragmentType type)
{
// create a task
return Task.Run(() => {
// check the listening state
if (_listening) {
// error
Log.Singleton.LogError("Can't send a fragment while listening");
// delete message
lock (message) {
MessageCenter.Singleton.Messages.Remove(BitConverter.ToUInt16(message.ID, 0));
}
// cancel
return;
}
// append CRC checksum
CRC.GenerateChecksum(ref fragment);
// need to lock to prevent multiple tasks trying to send simultaneously
lock (_clientMutex) {
// check if we want to lose some fragments
if (Options.LoseFragments) {
// get a random value
var random = new Random();
if ((ushort) random.Next() % 100 < 30) {
// 30% of fragments will be lost
// log that
Log.Singleton.LogMessage($"Purposefully losing a fragment of type <{type}>");
// exit
return;
}
}
// check if we want to corrupt some fragments
if (Options.SendCorrupt) {
// get a random value
var random = new Random();
if ((ushort) random.Next() % 100 < 40) {
// 40% of fragments will be corrupted
// log that
Log.Singleton.LogMessage($"Purposefully corrupting a fragment of type <{type}>");
// change random bytes
for (int i = 0, imax = Math.Abs(random.Next() + 2) % 16; i < imax; ++i) {
fragment[random.Next() % fragment.Length] = (byte) random.Next();
}
}
}
// create a client
_client = new UdpClient();
// bind it
try {
_client.Client.Bind(new IPEndPoint(IPAddress.Any, Options.Port));
}
catch (SocketException) {
// nope, can't bind to that port
Log.Singleton.LogError($"Failed to bind the sending socket to the port <{Options.Port}>");
// remove client
_client = null;
// remove message
lock (message) {
MessageCenter.Singleton.Messages.Remove(BitConverter.ToUInt16(message.ID, 0));
}
// stop
return;
}
// log
lock (message) {
Log.Singleton.LogMessage(
$"Sending a <{type}> fragment for message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> to <{message.RemoteEndPoint}>");
}
// send the fragment
lock (message) {
_client.Send(fragment, fragment.Length, message.RemoteEndPoint);
}
// close and remove client
_client.Close();
_client = null;
}
});
}
/// <summary>
/// Sends end fragment for a message.
/// </summary>
private void SendEndFragment(Message message, int retries = 0)
{
// create a task
Task.Run(() => {
// ask for an end fragment
byte[] fragment;
lock (message) {
fragment = Fragmenter.MakeEndFragment(message);
}
// send the fragment
SendFragment(message, fragment, FragmentType.End)
// listen
.ContinueWith(task => Listen())
// handle timeout
.ContinueWith(task => {
// check the result
if (!task.Result.Result) {
// timeout, check retries
if (retries < Options.Retries)
SendEndFragment(message, retries + 1);
else {
// message timed out
lock (message) {
MessageCenter.Singleton.Messages.Remove(BitConverter.ToUInt16(message.ID, 0));
// log
Log.Singleton.LogError(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> timed out");
MessageCenter.Singleton.FireChange(MessageStatus.TimedOut);
}
}
}
});
});
}
/// <summary>
/// Send a prepare fragment for a message.
/// </summary>
public void SendPrepareFragment(Message message, int retries = 0)
{
// create a task
Task.Run(() => {
// create a prepare fragment
byte[] prepareFragment;
lock (message) {
prepareFragment = Fragmenter.MakePrepareFragment(message);
}
// update status
lock (message) {
message.Status = MessageStatus.Handshaking;
}
// log that
lock (message) {
Log.Singleton.LogMessage(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> is in state <{message.Status}>");
MessageCenter.Singleton.FireChange(message.Status);
}
// go ahead, send it
SendFragment(message, prepareFragment, FragmentType.Prepare)
// listen
.ContinueWith(task => Listen())
// handle timeout
.ContinueWith(task => {
// check the result
if (!task.Result.Result) {
// timeout, check retries
if (retries < Options.Retries)
SendPrepareFragment(message, retries + 1);
else {
// message timed out
lock (message) {
MessageCenter.Singleton.Messages.Remove(BitConverter.ToUInt16(message.ID, 0));
// log
Log.Singleton.LogError(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> timed out");
MessageCenter.Singleton.FireChange(MessageStatus.TimedOut);
}
}
}
});
});
}
/// <summary>
/// Sends a prepared fragment for a message.
/// </summary>
public void SendPreparedFragment(Message message)
{
// create a task
Task.Run(() => {
// ask for a prepared fragment
byte[] fragment;
lock (message) {
fragment = Fragmenter.MakePreparedFragment(message);
}
// send the fragment
SendFragment(message, fragment, FragmentType.Prepared)
// listen
.ContinueWith(task => Listen(false));
});
}
/// <summary>
/// Sends ending okay fragment.
/// </summary>
public void SendOkayFragment(Message message)
{
// create a task
Task.Run(() => {
// ask for an end fragment
byte[] fragment;
lock (message) {
fragment = Fragmenter.MakeOkayFragment(message);
}
// send the fragment
SendFragment(message, fragment, FragmentType.Okay)
// set status
.ContinueWith(task => {
lock (message) {
message.Status = MessageStatus.Finished;
Log.Singleton.LogMessage(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> is in state <{message.Status}>");
MessageCenter.Singleton.FireChange(message.Status);
}
});
});
}
/// <summary>
/// Sends a missing fragment for a message.
/// </summary>
public void SendMissingFragment(Message message, List<ushort> missingList)
{
// create a task
Task.Run(() => {
// ask for a missing fragment
byte[] fragment;
lock (message) {
fragment = Fragmenter.MakeMissingFragment(message, missingList);
}
// send the fragment
SendFragment(message, fragment, FragmentType.Missing)
// listen
.ContinueWith(task => Listen(false));
});
}
/// <summary>
/// Sends only missing parts of a message.
/// </summary>
public void SendDataFragments(Message message, List<ushort> missingList)
{
// create a task
Task.Run(() => {
// set state
lock (message) {
message.Status = MessageStatus.Transmitting;
}
// log that
lock (message) {
Log.Singleton.LogMessage(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> is in state <{message.Status}>");
MessageCenter.Singleton.FireChange(message.Status);
}
// send missing data fragments
var sendTasks = new List<Task>();
lock (message) {
foreach (var missingNumber in missingList) {
// request a data fragment
var fragment = Fragmenter.MakeDataFragment(message, missingNumber);
// send it
var task = SendFragment(message, fragment, FragmentType.Data);
sendTasks.Add(task);
task.ContinueWith(t => {
lock (message) {
// update progress
MessageCenter.Singleton.FireProgress(missingNumber, message.PartCount);
// increment data counter
message.DataCounter++;
}
});
}
}
// TODO: Handle keep-alive fragments
Task.WhenAll(sendTasks).ContinueWith(task => {
// set state
lock (message) {
message.Status = MessageStatus.Ending;
}
// log that
lock (message) {
Log.Singleton.LogMessage(
$"Message <{message.ID[0].ToString("00")}{message.ID[1].ToString("00")}> is in state <{message.Status}>");
MessageCenter.Singleton.FireChange(message.Status);
}
// send end fragment
SendEndFragment(message);
});
});
}
/// <summary>
/// Creates a message and all it's fragments.
/// </summary>
/// <param name="remoteEndPoint">Where to send the message</param>
/// <param name="messageString">String to send</param>
/// <param name="maxFragmentSize">Maximum size of one fragment in bytes</param>
public static Message CreateMessage(IPEndPoint remoteEndPoint, string messageString, ushort maxFragmentSize)
{
// convert message string to bytes
var messageStringBytes = Encoding.ASCII.GetBytes(messageString);
// create a sorted list of fragments
var fragmentList = new SortedList<ushort, byte[]>();
// add all fragments
while (messageStringBytes.Length > 0) {
// get the fragment bytes
byte[] bytes;
// check the remaining size
if (messageStringBytes.Length > maxFragmentSize) {
// take maximum allowed bytes and make a fragment
bytes = messageStringBytes.Take(maxFragmentSize).ToArray();
// shift
messageStringBytes = messageStringBytes.Skip(maxFragmentSize).ToArray();
}
else {
// take whole fragment
bytes = messageStringBytes;
messageStringBytes = new byte[0];
}
// add the fragment to the list
fragmentList.Add((ushort) fragmentList.Count, bytes);
}
// create a message
var message = new Message((ushort) fragmentList.Count, fragmentList) {
RemoteEndPoint = remoteEndPoint,
Text = messageString
};
// return the message
return message;
}
/// <summary>
/// Makes a prepare fragment.
/// </summary>
public static byte[] MakePrepareFragment(Message message)
{
// the resulting array of bytes
var data = new List<byte>();
// add the type
data.Add((byte) FragmentType.Prepare);
// add the id
data.AddRange(message.ID);
// add fragment count
data.AddRange(BitConverter.GetBytes(message.PartCount));
// add name
data.AddRange(Encoding.ASCII.GetBytes(Options.Name));
// return data
return data.ToArray();
}
/// <summary>
/// Makes an okay fragment.
/// </summary>
public static byte[] MakeOkayFragment(Message message)
{
// the resulting array of bytes
var data = new List<byte>();
// add the type
data.Add((byte) FragmentType.Okay);
// add the id
data.AddRange(message.ID);
// return data
return data.ToArray();
}
/// <summary>
/// Makes a missing fragment.
/// </summary>
public static byte[] MakeMissingFragment(Message message, List<ushort> missingList)
{
// the resulting array of bytes
var data = new List<byte>();
// add the type
data.Add((byte) FragmentType.Missing);
// add the id
data.AddRange(message.ID);
// add missing fragments
foreach (var missingFragment in missingList) {
data.AddRange(BitConverter.GetBytes(missingFragment));
}
// return data
return data.ToArray();
}
/// <summary>
/// Makes a data fragment for a fragment of a message.
/// </summary>
public static byte[] MakeDataFragment(Message message, ushort number)
{
// the resulting array of bytes
var data = new List<byte>();
// add the type
data.Add((byte) FragmentType.Data);
// add the id
data.AddRange(message.ID);
// add the fragment number
data.AddRange(BitConverter.GetBytes(number));
// add data
data.AddRange(message.PartList[number]);
// return data
return data.ToArray();
}
