/// <summary>
/// Asynchronously transmits the message passed to the destination
/// indicated by the <see paramref="remoteEP" /> parameter.
/// </summary>
/// <param name="remoteEP">The destination SIP endpoint's <see cref="NetworkBinding" />.</param>
/// <param name="message">The <see cref="SipMessage" /> to be transmitted.</param>
/// <exception cref="SipTransportException">Thrown if the remote endpoint rejected the message or timed out.</exception>
public void Send(NetworkBinding remoteEP, SipMessage message)
{
if (disabled)
{
return;
}
if ((traceMode & SipTraceMode.Send) != 0)
{
SipHelper.Trace(string.Format("UDP: sending to {0}", remoteEP), message);
}
try
{
sock.SendTo(message.ToArray(), remoteEP);
}
catch (SocketException e)
{
// $todo(jeff.lill):
//
// This is just copied from the TCP transport. It probably
// doesn't apply here.
switch ((SocketError)e.ErrorCode)
{
case SocketError.ConnectionAborted:
case SocketError.ConnectionRefused:
case SocketError.ConnectionReset:
case SocketError.HostDown:
case SocketError.HostNotFound:
case SocketError.HostUnreachable:
throw new SipTransportException(SipTransportException.ErrorType.Rejected, e.Message, e);
case SocketError.TimedOut:
throw new SipTransportException(SipTransportException.ErrorType.Timeout, e.Message, e);
default:
throw;
}
}
}
/// <summary>
/// Asynchronously transmits the message passed to the destination
/// indicated by the <see paramref="remoteEP" /> parameter.
/// </summary>
/// <param name="remoteEP">The destination SIP endpoint's <see cref="NetworkBinding" />.</param>
/// <param name="message">The <see cref="SipMessage" /> to be transmitted.</param>
/// <remarks>
/// Note that this method will go to some lengths to send the message
/// down an existing connection to this endpoint.
/// </remarks>
/// <exception cref="SipTransportException">Thrown if the remote endpoint rejected the message or timed out.</exception>
public void Send(NetworkBinding remoteEP, SipMessage message)
{
string key = remoteEP.ToString();
EnhancedSocket sock;
Connection con;
using (TimedLock.Lock(this))
{
if (listener == null)
{
throw new ObjectDisposedException("Transport is closed.");
}
if (disabled)
{
return;
}
if ((traceMode & SipTraceMode.Send) != 0)
{
SipHelper.Trace(string.Format("TCP: sending to {0}", remoteEP), message);
}
// Send the message down an existing connection to this
// endpoint (if there is one).
if (connections.TryGetValue(key, out con))
{
con.Send(message);
return;
}
}
// Otherwise establish a connection to the endpoint and transmit
// the message. Note that I'm establishing the connection outside
// of the lock so processing on other connections can continue
// while the connection is established.
try
{
sock = new EnhancedSocket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp);
sock.Connect(remoteEP);
}
catch (SocketException e)
{
switch ((SocketError)e.ErrorCode)
{
case SocketError.ConnectionAborted:
case SocketError.ConnectionRefused:
case SocketError.ConnectionReset:
case SocketError.HostDown:
case SocketError.HostNotFound:
case SocketError.HostUnreachable:
throw new SipTransportException(SipTransportException.ErrorType.Rejected, e.Message, e);
case SocketError.TimedOut:
throw new SipTransportException(SipTransportException.ErrorType.Timeout, e.Message, e);
default:
throw;
}
}
using (TimedLock.Lock(this))
{
if (listener == null)
{
// Transport must have been closed while we were outside of the lock.
sock.ShutdownAndClose();
throw new ObjectDisposedException("Transport is closed.");
}
if (connections.TryGetValue(key, out con))
{
// Another connection to this endpoint must have been established
// while we were outside of the lock. Close the new socket and
// use the existing connection.
sock.ShutdownAndClose();
con.Send(message);
return;
}
// Add the new connection to the collection and then
// send the message.
con = new Connection(this, sock, remoteEP);
connections.Add(key, con);
con.Send(message);
}
}
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);
}
}
}
}
/// <summary>
/// Called when a packet is received by the socket from a remote endpoint.
/// </summary>
/// <param name="ar">The <see cref="IAsyncResult" />.</param>
private void OnReceive(IAsyncResult ar)
{
byte[] packet = null;
IPEndPoint remoteEP = new IPEndPoint(IPAddress.Any, 0);
int cb;
SipMessage message;
recvPending = false;
if (sock == null || recvBuf == null)
{
return;
}
try
{
cb = sock.EndReceiveFrom(ar, ref recvEP);
}
catch (Exception e)
{
// Log the exception if the socket appears to be open and then submit
// another receive request.
if (sock.IsOpen)
{
SysLog.LogException(e);
try
{
recvEP = new IPEndPoint(IPAddress.Any, 0);
sock.BeginReceiveFrom(recvBuf, 0, recvBuf.Length, SocketFlags.None, ref recvEP, onRecv, null);
}
catch (Exception e2)
{
SysLog.LogException(e2, "SIP UDP transport is no longer able to receive packets.");
}
}
return;
}
// $todo(jeff.lill): This is where I need to add source filtering.
// Make a copy of what we received before initiating the next packet receive.
try
{
packet = Helper.Extract(recvBuf, 0, cb);
remoteEP = (IPEndPoint)recvEP;
}
catch (Exception e)
{
SysLog.LogException(e);
}
// Initiate the receive of the next message
lock (syncLock)
{
if (sock == null || !sock.IsOpen)
{
return;
}
try
{
recvEP = new IPEndPoint(IPAddress.Any, 0);
recvPending = true;
sock.BeginReceiveFrom(recvBuf, 0, recvBuf.Length, SocketFlags.None, ref recvEP, onRecv, null);
}
catch (Exception e)
{
SysLog.LogException(e);
}
}
// Parse and dispatch the message
if (packet == null)
{
return;
}
// It looks like SIP clients like X-Lite send 4 byte CRLF CRLF messages
// periodically over UDP to keep NAT mappings alive. I'm going to
// ignore these messages.
if (packet.Length == 4)
{
return;
}
// Looks like we have a real message.
try
{
try
{
message = SipMessage.Parse(packet, true);
}
catch (Exception e)
{
SipHelper.Trace(string.Format("UDP: UNPARSABLE message received from {0}: [{1}]", remoteEP, e.Message), Helper.FromUTF8(packet));
throw;
}
message.SourceTransport = this;
message.RemoteEndpoint = remoteEP;
}
catch (SipException e)
{
e.BadPacket = packet;
e.SourceEndpoint = remoteEP;
SysLog.LogException(e);
return;
}
catch (Exception e)
{
SipException sipException;
sipException = new SipException("Error parsing SIP message.", e);
sipException.Transport = string.Format("UDP [{0}]", localEP);
sipException.BadPacket = packet;
sipException.SourceEndpoint = remoteEP;
SysLog.LogException(sipException);
return;
}
if (disabled)
{
return;
}
if ((traceMode & SipTraceMode.Receive) != 0)
{
SipHelper.Trace(string.Format("UDP: received from {0}", remoteEP), message);
}
router.Route(this, message);
}