/// <summary>
/// Fragments the given message into a number of smaller messages for sending over the network
/// </summary>
/// <returns>An array of network mesages belonging which are the fragments of the given message</returns>
public NetworkMessage[] Fragment(NetworkMessage message)
{
List<byte[]> fragments = new List<byte[]>();
NetworkMessage[] messages;
int numRead = 1;
using (MemoryStream ms = new MemoryStream(message.GzData))
{
while (numRead > 0)
{
byte[] readBytes = new byte[FragmentSize];
numRead = ms.Read(readBytes, 0, FragmentSize);
if (numRead > 0)
{
if (numRead < FragmentSize)
{
byte[] fragData = new byte[numRead];
Array.Copy(readBytes, fragData, numRead);
fragments.Add(fragData);
}
else
{
fragments.Add(readBytes);
}
}
}
messages = new NetworkMessage[fragments.Count];
for (int i = 0; i < fragments.Count; i++)
{
NetworkMessage fragmentMessage = new NetworkMessage(message.SenderID, message.DestinationID, message.MessageID, message.Type,
fragments[i], i, fragments.Count, message.Lifetime);
messages[i] = fragmentMessage;
}
}
return messages;
}
/// <summary>
/// Stores a message fragment, if all the fragments of a message are stored MessageDefragmented event is fired
/// </summary>
public void Defragment(NetworkMessage message)
{
NetworkMessage[] buffer;
List<int> fragmentsNeededList = null;
Debug.WriteLine("Fragment: " + message.FragmentNumber + " size: " + message.Data.Length);
if (incomingFragmentBuffer.ContainsKey(message.MessageID))
{
// first fragment has already been received so add to existing buffer
buffer = (NetworkMessage[])incomingFragmentBuffer[message.MessageID];
}
else
{
// This is the first fragement of a message received, so create a new buffer
buffer = new NetworkMessage[message.FragmentTotal];
messageFragmentsRequired[message.MessageID] = new List<int>(message.FragmentTotal);
for (int i = 0; i < message.FragmentTotal; i++)
{
((List<int>) messageFragmentsRequired[message.MessageID]).Add(i);
}
messageExpiryTimes.Add(new TickGuid(message.MessageID, message.Lifetime));
}
fragmentsNeededList = (List<int>) messageFragmentsRequired[message.MessageID];
buffer[message.FragmentNumber] = message;
incomingFragmentBuffer[message.MessageID] = buffer;
fragmentsNeededList.Remove(message.FragmentNumber);
if (fragmentsNeededList.Count == 0)
{
byte[] messageData;
using (MemoryStream ms = new MemoryStream())
{
for (int j = 0; j < buffer.Length; j++)
{
ms.Write(buffer[j].Data, 0, buffer[j].Data.Length);
}
messageData = new byte[ms.Length];
messageData = ms.ToArray();
}
MessageDefragmented(this, new MessageDefragmentedEventArgs(buffer[0].DestinationID, buffer[0].SenderID, buffer[0].MessageID, messageData));
incomingFragmentBuffer.Remove(message.MessageID);
messageFragmentsRequired.Remove(message.MessageID);
}
else
{
startMessageLifetimeTimer();
}
}
private void MessageLifetimeTimerTimeout(object ob)
{
Debug.WriteLine("MessageLifetimeTimerTimeout happened");
lock (messageExpiryTimes)
{
List<TickGuid> expired = messageExpiryTimes.FindAll(earlierThanNow);
Guid[] guids = new Guid[expired.Count];
foreach (TickGuid item in expired)
{
// check if it's fragments being sent in messageCache
if (outgoingFragments.ContainsKey(item.id))
{
Debug.WriteLine(String.Format("Expiring from fragment store {0}", item.id));
outgoingFragments.Remove(item.id);
}
if (incomingFragmentBuffer.ContainsKey(item.id))
{
NetworkMessage[] messageFragments = (NetworkMessage[])incomingFragmentBuffer[item.id];
for (int i = 0; i < messageFragments.Length; i++)
{
if (messageFragments[i] == null)
{
Debug.WriteLine(String.Format("Need to request resend of message {0} fragment {1}", item.id, i));
NetworkMessage message = new NetworkMessage(localID, Guid.Empty, Guid.NewGuid(), NetworkMessageType.FragmentRequest, item.id.ToByteArray(), i, 1, 5000);
sendMessage(message);
}
}
}
messageExpiryTimes.Remove(item);
//Schedule next time to try
messageExpiryTimes.Add(new TickGuid(item.id, 5000));
}
}
if (messageExpiryTimes.Count == 0)
{
if (messageLifetimeTimer != null)
{
messageLifetimeTimer.Dispose();
messageLifetimeTimer = null;
}
}
}
public MessageEventArgs(NetworkMessage message)
{
this.gzData = message.GzData;
this.senderID = message.SenderID;
this.destinationID = message.DestinationID;
}
public void FireMessageReceived(NetworkMessage message)
{
if (this.MessageReceived != null)
{
MessageReceived(this, new MessageEventArgs(message));
}
}
private void sendMessage(NetworkMessage message)
{
SendQueue.Enqueue(message);
messageToSendEvent.Set();
}
private void ReceiveThread()
{
try
{
udpReceiveClient = new UdpClient(port, AddressFamily.InterNetwork);
IPEndPoint receivedFrom = new IPEndPoint(IPAddress.Any, 0);
byte[] receivedBytes = new byte[100000];
while (keepRecieving)
{
receivedBytes = udpReceiveClient.Receive(ref receivedFrom);
int receivedLength = receivedBytes.Length;
if (receivedLength > 36)
{
NetworkMessage message = new NetworkMessage(receivedBytes);
Debug.WriteLine(String.Format("Received {0} from {1}", message.Type, receivedFrom));
switch (message.Type)
{
case NetworkMessageType.Message:
ReceiveQueue.Enqueue(message);
messageReceivedEvent.Set();
break;
case NetworkMessageType.DirectRequest:
if (message.DestinationID == this.localID)
{
Debug.WriteLine("Received direct request for " + message.DestinationID.ToString());
NetworkMessage replyMessage = new NetworkMessage(this.localID, message.SenderID, Guid.NewGuid(), NetworkMessageType.DirectReply, message.Data, 1, 1, 50000);
sendMessage(replyMessage);
}
break;
case NetworkMessageType.DirectReply:
if (message.DestinationID == localID)
{
Debug.WriteLine("Recieved reply for " + message.DestinationID.ToString());
MessageRequest messageReq = new MessageRequest();
messageReq.Address = receivedFrom.Address;
messageReq.MessageID = new Guid(message.Data);
messageReq.Fragment = -1;
directUdpTargets.Enqueue(messageReq);
directUdpEvent.Set();
}
break;
case NetworkMessageType.FragmentRequest:
if (message.SenderID != localID)
{
Guid messageRequestID = new Guid(message.Data);
Debug.WriteLine(String.Format("Request for resend of message {0} fragment {1}", messageRequestID, message.FragmentNumber));
MessageRequest fragmentReq = new MessageRequest();
fragmentReq.Address = receivedFrom.Address;
fragmentReq.MessageID = new Guid(message.Data);
fragmentReq.Fragment = message.FragmentNumber;
directUdpTargets.Enqueue(fragmentReq);
directUdpEvent.Set();
Thread.Sleep(0);
}
break;
}
}
}
}
catch (SocketException ex)
{
Debug.WriteLine(String.Format("SocketException: {0} {1}\r\n{2}", ex.ErrorCode, ex.Message, ex.StackTrace));
}
}
public void SendFragments(byte[] data, Guid destinationID)
{
Guid messageID = Guid.NewGuid();
Debug.WriteLine("Created message " + messageID.ToString());
// Make the lifetime of the message 30 seconds
NetworkMessage largeMessage = new NetworkMessage(localID, destinationID, messageID, NetworkMessageType.Message,
data, 1,1, 300000);
NetworkMessage[] fragments = this.Fragment(largeMessage);
outgoingFragments[largeMessage.MessageID] = fragments;
//double the lifetime in send cache so that receivers have a chance to request fragments within one timespan before it's expired
messageExpiryTimes.Add(new TickGuid(largeMessage.MessageID, (largeMessage.Lifetime*2)));
Debug.WriteLine("Message fragmented in " + fragments.Length + " fragments.");
foreach (NetworkMessage message in fragments)
{
sendMessage(message);
Thread.Sleep(0);
}
startMessageLifetimeTimer();
}
public void SendDirect(byte[] data, Guid destinationID)
{
Guid messageID = Guid.NewGuid();
NetworkMessage[] fragments = null;
TickGuid expiryTime = new TickGuid();
expiryTime.id = messageID;
NetworkMessage message = new NetworkMessage(localID, destinationID, messageID, NetworkMessageType.Message,
data, 1, 1, 10000);
if (message.GzData.Length > FragmentSize)
{
message.Lifetime = 30000;
//Break the message up if it's large
fragments = this.Fragment(message);
expiryTime.SetExpityTime(message.Lifetime);
}
else
{
fragments = new NetworkMessage[1];
fragments[0] = message;
expiryTime.SetExpityTime(message.Lifetime);
}
Debug.WriteLine(String.Format("Adding {0} to store in {1} fragments", messageID, fragments.Length));
outgoingFragments[messageID] = fragments;
messageExpiryTimes.Add(expiryTime);
// make the lifetime of the direct request message 5 seconds
NetworkMessage directRequestMessage = new NetworkMessage(localID, destinationID, Guid.NewGuid(), NetworkMessageType.DirectRequest, messageID.ToByteArray(), 1, 1, 5000);
sendMessage(directRequestMessage);
startMessageLifetimeTimer();
}
public void Send(byte[] bytes, Guid destinationID)
{
NetworkMessage message = new NetworkMessage(localID, destinationID, Guid.NewGuid(), NetworkMessageType.Message, bytes, 1, 1, 50000);
if (message.GzData.Length > FragmentSize)
{
// This is a large message, break into fragments
SendFragments(bytes, destinationID);
}
else
{
Debug.WriteLine("Created message " + message.MessageID.ToString());
sendMessage(message);
}
}
public MessageDefragmentedEventArgs(NetworkMessage message)
: base(message)
{
this.gzData = message.Data;
}
