/// <summary>
/// Process the clients identity structure <see cref="DtmIdentity"/>.
/// </summary>
///
/// <param name="PacketStream">A Stream containing the raw packet data</param>
private void ProcessSync(MemoryStream PacketStream)
{
// get the header
DtmPacket pktHdr = new DtmPacket(PacketStream);
// read the data
byte[] data = new byte[pktHdr.PayloadLength];
PacketStream.Read(data, 0, data.Length);
// use clients symmetric key to decrypt data
byte[] dec = SymmetricTransform(_cltSymProcessor, data);
// remove random padding
dec = UnwrapMessage(dec);
// get the identity
_cltIdentity = new DtmIdentity(dec);
// pass id to the client, include oid
long resp = 0;
if (IdentityReceived != null)
{
DtmIdentityEventArgs args = new DtmIdentityEventArgs(DtmExchangeFlags.Init, _cltIdentity.OptionFlag, _cltIdentity);
IdentityReceived(this, args);
resp = args.Flag;
if (args.Cancel)
{
// back out of session
TearDown();
}
}
// get the params oid
_cltAsmParams = GetAsymmetricParams(_cltIdentity.PkeId);
}
/// <summary>
/// Processes the clients public identity and clients Auth-Stage PKE parameter set Id; <see cref="IAsymmetricParameters"/>.
/// <para>Process the clients Auth-Stage public identity structure; <see cref="DtmIdentity"/></para>
/// </summary>
///
/// <param name="PacketStream">A Stream containing the raw packet data</param>
///
/// <remarks>Fires the <see cref="IdentityReceived"/> event; returning the <see cref="DtmIdentityEventArgs"/> object containing the clients public id structure.
/// <para>The session can be aborted by setting the DtmIdentityEventArgs Cancel flag to true.</para>
/// </remarks>
private void ProcessInit(MemoryStream PacketStream)
{
// seek past header
PacketStream.Seek(DtmPacket.GetHeaderSize(), SeekOrigin.Begin);
// get the clients id structure
_cltIdentity = new DtmIdentity(PacketStream);
// get client asymmetric params
_cltAsmParams = GetAsymmetricParams(_cltIdentity.PkeId);
// store the auth session
_cltAuthSession = _cltIdentity.Session;
// pass it to the client again, so it can be refused on basis of params
long resp = 0;
if (IdentityReceived != null)
{
DtmIdentityEventArgs args = new DtmIdentityEventArgs(DtmExchangeFlags.Init, 0, _cltIdentity);
IdentityReceived(this, args);
resp = args.Flag;
if (args.Cancel)
{
// back out of session
TearDown();
}
}
}
/// <summary>
/// Process the clients private identity.
/// <para>Decrypts and stores the clients private identity using the clients Auth-Stage Symmetric Key.</para>
/// </summary>
///
/// <param name="PacketStream">A Stream containing the raw packet data</param>
private void ProcessAuth(MemoryStream PacketStream)
{
// get the header
DtmPacket pktHdr = new DtmPacket(PacketStream);
byte[] data = new byte[pktHdr.PayloadLength];
PacketStream.Read(data, 0, data.Length);
// create the clients auth-stage symmetric cipher
_cltSymProcessor = SymmetricInit(_cltIdentity.Session, _cltKeyParams);
// decrypt the payload
byte[] dec = SymmetricTransform(_cltSymProcessor, data);
// remove random padding
dec = UnwrapMessage(dec);
// get the clients private id
_cltIdentity = new DtmIdentity(new MemoryStream(dec));
// notify user
long resp = 0;
if (IdentityReceived != null)
{
DtmIdentityEventArgs args = new DtmIdentityEventArgs(DtmExchangeFlags.Auth, resp, _cltIdentity);
IdentityReceived(this, args);
resp = args.Flag;
if (args.Cancel)
{
// back out of session
TearDown();
}
}
}
/// <summary>
/// Processes the clients public identity field for preliminary authentication.
/// <para>Process the clients partial Auth-Stage public identity structure; <see cref="DtmIdentity"/></para>
/// </summary>
///
/// <param name="PacketStream">A Stream containing the raw packet data</param>
///
/// <remarks>
/// The client auto-negotiates to the security level of the server (the host accepting the connection request).
/// Fires the <see cref="IdentityReceived"/> event; returning the <see cref="DtmIdentityEventArgs"/> object containing the clients public id structure.
/// <para>The session can be aborted by setting the DtmIdentityEventArgs Cancel flag to true.</para>
/// </remarks>
private void ProcessConnect(MemoryStream PacketStream)
{
// seek past header
PacketStream.Seek(DtmPacket.GetHeaderSize(), SeekOrigin.Begin);
// get the clients id structure
_cltIdentity = new DtmIdentity(PacketStream);
// pass it to the client, evaluate the id
if (IdentityReceived != null)
{
DtmIdentityEventArgs args = new DtmIdentityEventArgs(DtmExchangeFlags.Init, 0, _cltIdentity);
IdentityReceived(this, args);
if (args.Cancel)
{
// back out of session
TearDown();
}
}
// synchronize security level with the server
if (!_isServer)
{
// get the servers security context and compare it to ours
DtmParamSets.SecurityContexts srvSec = (DtmParamSets.SecurityContexts)_cltIdentity.OptionFlag;
DtmParamSets.SecurityContexts cltSec = DtmParamSets.GetContext(_dtmParameters.OId);
if (cltSec != srvSec)
{
// match servers security parameters
if (!NegotiateSecurity(srvSec))
{
// the negotiation failed
Disconnect();
}
}
}
}
/// <summary>
/// Fires when a packet containing an identity is received, the args contain the id
/// </summary>
private void OnIdentityReceived(object owner, DtmIdentityEventArgs args)
{
Console.WriteLine(CON_TITLE + String.Format("Server received an identity packet: {0}", IdToString(args.DtmID.Identity)));
}
