public void Unmarshal(TransportPacket input, ITransportDeliveryCharacteristics tdc, EventHandler<MessageEventArgs> messageAvailable)
{
// <item>Message fits within the transport packet length, so sent unmodified
// <pre>[byte:message-type] [byte:channelId] [uint32:packet-size]
// [bytes:content]</pre>
// </item>
// <item> if the message is the first fragment, then the high-bit is
// set on the message-type; the number of fragments is encoded using
// the adaptive <see cref="ByteUtils.EncodeLength(int)"/> format.
// <pre>[byte:message-type'] [byte:channelId] [uint32:packet-size]
// [byte:seqno] [bytes:encoded-#-fragments] [bytes:frag]</pre>
// </item>
// <item> for all subsequent fragments; seqno' = seqno | 128;
// the number of fragments is encoded using the adaptive
// <see cref="ByteUtils.EncodeLength(int)"/> format.
// <pre>[byte:message-type'] [byte:channelId] [uint32:packet-size]
// [byte:seqno'] [bytes:encoded-fragment-#] [bytes:frag]</pre>
// Fastpath: if the message-type doesn't have the high-bit set,
// then this is a non-fragmented message
if ((input.ByteAt(0) & 128) == 0)
{
// If the submarshaller uses LWMCFv1.1 then we would have just
// sent the packet as-is; if not, then we'll have prefixed a
// LWMCFv1.1 header which must be first removed
if (!subMarshallerIsLwmcf11)
{
input.RemoveBytes(0, (int)LWMCFv11.HeaderSize);
}
subMarshaller.Unmarshal(input, tdc, messageAvailable);
return;
}
MessageType type;
byte channelId;
uint contentLength;
Stream s = input.AsReadStream();
LWMCFv11.DecodeHeader(out type, out channelId, out contentLength, s);
byte seqNo = (byte)s.ReadByte();
TransportPacket subPacket;
if ((seqNo & 128) == 0)
{
// This starts a new message
uint numFrags = (uint)ByteUtils.DecodeLength(s);
subPacket = UnmarshalFirstFragment(seqNo, numFrags,
input.SplitOut((int)(s.Length - s.Position)), tdc);
}
else
{
// This is a message in progress
seqNo = (byte)(seqNo & ~128);
uint fragNo = (uint)ByteUtils.DecodeLength(s);
subPacket = UnmarshalFragInProgress(seqNo, fragNo,
input.SplitOut((int)(s.Length - s.Position)), tdc);
}
if (subPacket != null)
{
subMarshaller.Unmarshal(subPacket, tdc, messageAvailable);
subPacket.Dispose();
}
}
public void TestRemoveBytes()
{
byte[] bytes = new byte[256];
for (int i = 0; i < bytes.Length; i++) { bytes[i] = (byte)(i % 256); }
byte[] reversed = new byte[bytes.Length];
Buffer.BlockCopy(bytes, 0, reversed, 0, bytes.Length);
Array.Reverse(reversed);
TransportPacket tp = new TransportPacket();
Stream stream = tp.AsWriteStream();
// we'll make 256 copies of [0,1,...,254,255,255,254,...,1,0]
for (int i = 0; i < 256; i++)
{
stream.Write(bytes, 0, bytes.Length);
stream.Write(reversed, 0, reversed.Length);
}
stream.Flush();
Assert.AreEqual((bytes.Length + reversed.Length) * 256, tp.Length);
byte[] copy = tp.ToArray();
Assert.AreEqual((bytes.Length + reversed.Length) * 256, tp.Length);
// Now remove successively larger chunks from between the bytes/reversed
// boundary points
int nextIndex = 0; // the start into the next bytes/reverse pair
for (int i = 0; i < bytes.Length / 2; i++)
{
Assert.AreEqual(0, tp.ByteAt(nextIndex));
Assert.AreEqual(1, tp.ByteAt(nextIndex + 1));
Assert.AreEqual(bytes.Length - 2, tp.ByteAt(nextIndex + bytes.Length - 2));
Assert.AreEqual(bytes.Length - 1, tp.ByteAt(nextIndex + bytes.Length - 1));
Assert.AreEqual(bytes.Length - 1, tp.ByteAt(nextIndex + bytes.Length));
Assert.AreEqual(bytes.Length - 2, tp.ByteAt(nextIndex + bytes.Length +1));
Assert.AreEqual(1,
tp.ByteAt(nextIndex + bytes.Length + reversed.Length - 2));
Assert.AreEqual(0,
tp.ByteAt(nextIndex + bytes.Length + reversed.Length - 1));
// remove 2i bytes from the end of the bytes copy extending
tp.RemoveBytes(nextIndex + bytes.Length - i, 2 * i);
Assert.AreEqual((bytes.Length + reversed.Length) * 256 - 2 * i * (i+1) / 2, tp.Length);
Assert.AreEqual(0, tp.ByteAt(nextIndex));
Assert.AreEqual(bytes.Length - i - 1, tp.ByteAt(nextIndex + bytes.Length - i - 1));
Assert.AreEqual(bytes.Length - i - 1, tp.ByteAt(nextIndex + bytes.Length - i));
Assert.AreEqual(0, tp.ByteAt(nextIndex + bytes.Length + reversed.Length - 2*i - 1));
nextIndex += bytes.Length + reversed.Length - 2 * i;
}
CheckDisposed(tp);
CheckForUndisposedSegments();
}
protected override void NotifyPacketReceived(TransportPacket packet)
{
if (packet.Length < PacketHeaderSize)
{
throw new TransportError(this,
"should not receive datagrams whose size is less than PacketHeaderSize bytes", packet);
}
uint packetSeqNo = 0;
packet.BytesAt(0, 4, (b,offset) => packetSeqNo = DataConverter.Converter.ToUInt32(b, offset));
packet.RemoveBytes(0, 4);
// We handle wrap around by checking if the difference between the
// packet-seqno and the expected next packet-seqno > uint.MaxValue / 2
// After all, it's unlikely that 2 billion packets will mysteriously disappear!
if (packetSeqNo < nextIncomingPacketSeqNo
&& nextIncomingPacketSeqNo - packetSeqNo < uint.MaxValue / 2) { return; }
nextIncomingPacketSeqNo = packetSeqNo + 1;
// pass it on
base.NotifyPacketReceived(packet);
}
public void TestDisposal()
{
TransportPacket packet = new TransportPacket(10);
packet.Dispose();
try
{
packet.Grow(20);
Assert.Fail("should have thrown ObjectDisposedException");
} catch(ObjectDisposedException) { /* expected */ }
try
{
packet.RemoveBytes(0,2);
Assert.Fail("should have thrown ObjectDisposedException");
} catch(ObjectDisposedException) { /* expected */ }
try
{
packet.ByteAt(0);
Assert.Fail("should have thrown ObjectDisposedException");
} catch(ObjectDisposedException) { /* expected */ }
try
{
packet.Consolidate();
Assert.Fail("should have thrown ObjectDisposedException");
} catch(ObjectDisposedException) { /* expected */ }
try
{
packet.Prepend(new byte[0]);
Assert.Fail("should have thrown ObjectDisposedException");
}
catch (ObjectDisposedException) { /* expected */ }
try
{
packet.Append(new byte[0]);
Assert.Fail("should have thrown ObjectDisposedException");
}
catch (ObjectDisposedException) { /* expected */ }
try
{
Console.WriteLine(packet.Length);
Assert.Fail("should have thrown ObjectDisposedException");
}
catch (ObjectDisposedException) { /* expected */ }
}
/// <summary>
/// Handle incoming packets from previously-unknown remote endpoints.
/// We check if the packet indicates a handshake and, if so, negotiate.
/// Otherwise we send a GT error message and disregard the packet.
/// </summary>
/// <param name="ep">the remote endpoint</param>
/// <param name="packet">the first packet</param>
protected void PreviouslyUnseenUdpEndpoint(EndPoint ep, TransportPacket packet)
{
TransportPacket response;
Stream ms;
// This is the GT (UDP) protocol 1.0:
// bytes 0 - 3: the protocol version (the result from ProtocolDescriptor)
// bytes 4 - n: the number of bytes in the capability dictionary (see ByteUtils.EncodeLength)
// bytes n+1 - end: the capability dictionary
// The # bytes in the dictionary isn't actually necessary in UDP, but oh well
foreach(TransportFactory<UdpHandle> factory in factories)
{
if(packet.Length >= factory.ProtocolDescriptor.Length &&
ByteUtils.Compare(packet.ToArray(0, factory.ProtocolDescriptor.Length),
factory.ProtocolDescriptor))
{
packet.RemoveBytes(0, factory.ProtocolDescriptor.Length);
ms = packet.AsReadStream();
Dictionary<string, string> dict = null;
try
{
uint count = ByteUtils.DecodeLength(ms); // we don't use it
dict = ByteUtils.DecodeDictionary(ms);
if(ms.Position != ms.Length)
{
byte[] rest = packet.ToArray();
log.Info(String.Format(
"{0} bytes still left at end of UDP handshake packet: {1} ({2})",
rest.Length, ByteUtils.DumpBytes(rest, 0, rest.Length),
ByteUtils.AsPrintable(rest, 0, rest.Length)));
}
ITransport result = factory.CreateTransport(UdpHandle.Bind(udpMultiplexer, ep));
if (ShouldAcceptTransport(result, dict))
{
// Send confirmation
// NB: following uses the format specified by LWMCF v1.1
response = new TransportPacket(LWMCFv11.EncodeHeader(MessageType.System,
(byte)SystemMessageType.Acknowledged,
(uint)factory.ProtocolDescriptor.Length));
response.Append(factory.ProtocolDescriptor);
udpMultiplexer.Send(response, ep);
NotifyNewTransport(result, dict);
}
else
{
// NB: following follows the format specified by LWMCF v1.1
response = new TransportPacket(LWMCFv11.EncodeHeader(MessageType.System,
(byte)SystemMessageType.IncompatibleVersion, 0));
udpMultiplexer.Send(response, ep);
result.Dispose();
}
return;
}
catch(Exception e)
{
log.Warn(String.Format("Error decoding handshake from remote {0}", ep), e);
}
}
}
// If we can figure out some way to say: the packet is an invalid form:
// response = new TransportPacket();
// ms = response.AsWriteStream();
// log.Info("Undecipherable packet (ignored)");
// // NB: following follows the format specified by LWMCF v1.1
// LWMCFv11.EncodeHeader(MessageType.System, (byte)SystemMessageType.UnknownConnexion,
// (uint)ProtocolDescriptor.Length, ms);
// ms.Write(ProtocolDescriptor, 0, ProtocolDescriptor.Length);
// ms.Flush();
// udpMultiplexer.Send(response, ep);
response = new TransportPacket();
ms = response.AsWriteStream();
log.Info("Unknown protocol version: "
+ ByteUtils.DumpBytes(packet.ToArray(), 0, 4) + " ["
+ ByteUtils.AsPrintable(packet.ToArray(), 0, 4) + "]");
// NB: following follows the format specified by LWMCF v1.1
LWMCFv11.EncodeHeader(MessageType.System, (byte)SystemMessageType.IncompatibleVersion,
0, ms);
ms.Flush();
udpMultiplexer.Send(response, ep);
}