/// <summary>
/// Completes the reception of bytes on a TCP connection.
/// </summary>
/// <param name="ar">The <see cref="IAsyncResult" /> instance returned by the initiating <see cref="BeginReceiveAll" /> call.</param>
/// <exception cref="SocketException">Thrown if the was an network error.</exception>
/// <exception cref="SocketClosedException">Thrown if the socket has been closed.</exception>
/// <remarks>
/// <note>
/// All successful calls to <see cref="BeginReceiveAll" /> must eventually be followed by a call to <see cref="EndReceiveAll" />.
/// </note>
/// </remarks>
public void EndReceiveAll(IAsyncResult ar)
{
lock (syncLock)
{
if (!isTcp)
{
throw new InvalidOperationException("[LiteSocket.EndReceiveAll] is not supported on UDP connections.");
}
try
{
sock.EndReceiveAll(ar);
}
finally
{
receivePending = false;
}
}
}
private void OnReceive(IAsyncResult ar)
{
List <SipMessage> received = null;
try
{
using (TimedLock.Lock(transport))
{
int cb;
int pos;
int cbContents;
SipHeader contentLength;
byte[] packet;
try
{
if (sock == null)
{
return;
}
if (contentBuf == null)
{
// We're reading a message envelope.
// Read packets into headerBuf until we can find the CRLFCRLF
// sequence marking the end of the message headers.
cb = sock.EndReceive(ar);
if (cb == 0)
{
// The socket has been closed on by the remote element.
CloseAndRemove();
return;
}
cbRecv += cb;
tryAgain:
// Remove any leading CR or LF characters by shifting the
// buffer contents. I know this isn't super efficient but
// we'll probably never actually see packets with this
// in the wild.
for (pos = 0; pos < cbRecv; pos++)
{
if (headerBuf[pos] != 0x0D && headerBuf[pos] != 0x0A)
{
break;
}
}
if (pos != 0)
{
if (pos == cbRecv)
{
// No data remaining in the buffer
cbRecv = 0;
sock.BeginReceive(headerBuf, 0, headerBuf.Length, SocketFlags.None, onRecv, null);
return;
}
Array.Copy(headerBuf, pos, headerBuf, 0, headerBuf.Length - pos);
cbRecv -= pos;
}
// Scan the message for the CRLFCRLF sequence terminating the
// message envelope.
pos = Helper.IndexOf(headerBuf, CRLFCRLF, 0, cbRecv);
if (pos != -1)
{
// We've got the message envelope
pos += 4; // Advance past the CRLFCRLF
// Parse the message headers and then get the Content-Length header
packet = Helper.Extract(headerBuf, 0, pos);
try
{
message = SipMessage.Parse(packet, false);
}
catch (Exception e)
{
SipHelper.Trace(string.Format("TCP: UNPARSABLE message received from {0}: [{1}]", remoteEP, e.Message), Helper.FromUTF8(packet));
throw;
}
contentLength = message[SipHeader.ContentLength];
if (contentLength == null || !int.TryParse(contentLength.Text, out cbContents) || cbContents < 0)
{
var e = new SipException("Malformed SIP message: Invalid or missing [Content-Length] header from streaming transport.");
e.Transport = "TCP";
e.BadPacket = packet;
e.SourceEndpoint = remoteEP;
throw e;
}
if (cbContents > MaxContentSize)
{
var e = new SipException("Invalid SIP message: [Content-Length={0}] exceeds [{1}].", cbContents, MaxContentSize);
e.Transport = "TCP";
e.BadPacket = packet;
e.SourceEndpoint = remoteEP;
throw e;
}
if (pos + cbContents <= cbRecv)
{
// We already have the message contents, so extract the contents,
// add them to the message, and then queue the message for delivery
// once we leave the lock.
message.Contents = Helper.Extract(headerBuf, pos, cbContents);
if (received == null)
{
received = new List <SipMessage>();
}
received.Add(message);
message = null;
// Shift any remaining data to the left in headerBuf,
// adjust cbRecv, and the loop to look for another
// message.
pos += cbContents;
cb = cbRecv - pos; // Bytes remaining in the buffer
if (cb == 0)
{
// No more data left in the buffer
cbRecv = 0;
sock.BeginReceive(headerBuf, 0, headerBuf.Length, SocketFlags.None, onRecv, null);
return;
}
Array.Copy(headerBuf, pos, headerBuf, 0, cb);
cbRecv = cb;
goto tryAgain;
}
// We don't have all of the message contents, so allocate a buffer for
// the contents, copy what we have already into this buffer, and then
// initiate a receive operation to read the remaining data.
contentBuf = new byte[cbContents];
cbRecv = cbRecv - pos; // Content bytes remaining in the buffer
Array.Copy(headerBuf, pos, contentBuf, 0, cbRecv);
sock.BeginReceiveAll(contentBuf, cbRecv, cbContents - cbRecv, SocketFlags.None, onRecv, null);
return;
}
// Throw an error if the header buffer is full and we still haven't
// found the end of the envelope.
if (cbRecv >= headerBuf.Length)
{
var e = new SipException("Malformed SIP message: Read [{0}] bytes and have not yet encountered end of headers.", headerBuf.Length);
e.Transport = "TCP";
e.SourceEndpoint = remoteEP;
throw e;
}
// Continue receiving header data.
sock.BeginReceive(headerBuf, cbRecv, headerBuf.Length - cbRecv, SocketFlags.None, onRecv, null);
}
else
{
// We're in the process of reading the message contents.
// Complete the contents receive operation and queue the
// message for delivery after we leave the lock.
sock.EndReceiveAll(ar);
message.Contents = contentBuf;
if (received == null)
{
received = new List <SipMessage>();
}
received.Add(message);
// Reset and start reading the next message envelope.
message = null;
contentBuf = null;
cbRecv = 0;
sock.BeginReceive(headerBuf, 0, headerBuf.Length, SocketFlags.None, onRecv, null);
}
}
catch (SocketException)
{
CloseAndRemove();
}
catch (Exception e)
{
SysLog.LogException(e);
CloseAndRemove();
}
}
}
finally
{
// Deliver any queued messages (outside of the lock)
if (received != null)
{
foreach (var message in received)
{
message.SourceTransport = transport;
message.RemoteEndpoint = remoteEP;
if ((transport.traceMode & SipTraceMode.Receive) != 0)
{
SipHelper.Trace(string.Format("TCP: received from {0}", remoteEP), message);
}
transport.router.Route(transport, message);
}
}
}
}
