/**
* <code>
* 2) Authenticate the State Cookie as one that it previously generated
* by comparing the computed MAC against the one carried in the
* State Cookie. If this comparison fails, the SCTP packet,
* including the COOKIE ECHO and any DATA chunks, should be silently
* discarded,
*
* 3) Compare the port numbers and the Verification Tag contained
* within the COOKIE ECHO chunk to the actual port numbers and the
* Verification Tag within the SCTP common header of the received
* packet. If these values do not match, the packet MUST be
* silently discarded.
*
* 4) Compare the creation timestamp in the State Cookie to the current
* local time. If the elapsed time is longer than the lifespan
* carried in the State Cookie, then the packet, including the
* COOKIE ECHO and any attached DATA chunks, SHOULD be discarded,
* and the endpoint MUST transmit an ERROR chunk with a "Stale
* Cookie" error cause to the peer endpoint.
*
* 5) If the State Cookie is valid, create an association to the sender
* of the COOKIE ECHO chunk with the information in the TCB data
* carried in the COOKIE ECHO and enter the ESTABLISHED state.
*
* 6) Send a COOKIE ACK chunk to the peer acknowledging receipt of the
* COOKIE ECHO. The COOKIE ACK MAY be bundled with an outbound DATA
* chunk or SACK chunk; however, the COOKIE ACK MUST be the first
* chunk in the SCTP packet.
*
* 7) Immediately acknowledge any DATA chunk bundled with the COOKIE
* ECHO with a SACK (subsequent DATA chunk acknowledgement should
* follow the rules defined in Section 6.2). As mentioned in step
* 6, if the SACK is bundled with the COOKIE ACK, the COOKIE ACK
* MUST appear first in the SCTP packet.
* </code>
*/
private Chunk[] cookieEchoDeal(CookieEchoChunk echo)
{
Chunk[] reply = new Chunk[0];
if (_state == State.CLOSED || _state == State.COOKIEWAIT || _state == State.COOKIEECHOED)
{
// Authenticate the State Cookie
CookieHolder cookie;
if (null != (cookie = checkCookieEcho(echo.getCookieData())))
{
// Compare the creation timestamp in the State Cookie to the current local time.
uint howStale = howStaleIsMyCookie(cookie);
if (howStale == 0)
{
//enter the ESTABLISHED state
_state = State.ESTABLISHED;
/*
* Send a COOKIE ACK chunk to the peer acknowledging receipt of the
* COOKIE ECHO. The COOKIE ACK MAY be bundled with an outbound DATA
* chunk or SACK chunk; however, the COOKIE ACK MUST be the first
* chunk in the SCTP packet.
*/
reply = new Chunk[1];
reply[0] = new CookieAckChunk();
}
else
{
reply = new Chunk[1];
/* If the elapsed time is longer than the lifespan
* carried in the State Cookie, then the packet, including the
* COOKIE ECHO and any attached DATA chunks, SHOULD be discarded,
* and the endpoint MUST transmit an ERROR chunk with a "Stale
* Cookie" error cause to the peer endpoint.*/
StaleCookieError sce = new StaleCookieError();
sce.setMeasure(howStale * 1000);
ErrorChunk ec = new ErrorChunk(sce);
reply[0] = ec;
}
}
else
{
Logger.Error("Got a COOKIE_ECHO that doesn't match any we sent. ?!?");
}
}
else
{
Logger.Debug("Got an COOKIE_ECHO when not closed - ignoring it");
}
return(reply);
}
protected VariableParam readErrorParam()
{
int type = _body.GetUShort();
int len = _body.GetUShort();
int blen = len - 4;
byte[] data;
KnownError var = null;
switch (type)
{
case 1:
var = new KnownError(1, "InvalidStreamIdentifier");
break; //[RFC4960]
case 2:
var = new KnownError(2, "MissingMandatoryParameter");
break; //[RFC4960]
case 3:
var = new StaleCookieError();
break; //[RFC4960]
case 4:
var = new KnownError(4, "OutofResource");
break; //[RFC4960]
case 5:
var = new KnownError(5, "UnresolvableAddress");
break; //[RFC4960]
case 6:
var = new KnownError(6, "UnrecognizedChunkType");
break; //[RFC4960]
case 7:
var = new KnownError(7, "InvalidMandatoryParameter");
break; //[RFC4960]
case 8:
var = new KnownError(8, "UnrecognizedParameters");
break; //[RFC4960]
case 9:
var = new KnownError(9, "NoUserData");
break; //[RFC4960]
case 10:
var = new KnownError(10, "CookieReceivedWhileShuttingDown");
break; //[RFC4960]
case 11:
var = new KnownError(11, "RestartofanAssociationwithNewAddresses");
break; //[RFC4960]
case 12:
var = new KnownError(12, "UserInitiatedAbort");
break; //[RFC4460]
case 13:
var = new ProtocolViolationError(13, "ProtocolViolation");
break; //[RFC4460]
// 14-159,Unassigned,
case 160:
var = new KnownError(160, "RequesttoDeleteLastRemainingIPAddress");
break; //[RFC5061]
case 161:
var = new KnownError(161, "OperationRefusedDuetoResourceShortage");
break; //[RFC5061]
case 162:
var = new KnownError(162, "RequesttoDeleteSourceIPAddress");
break; //[RFC5061]
case 163:
var = new KnownError(163, "AssociationAbortedduetoillegalASCONF-ACK");
break; //[RFC5061]
case 164:
var = new KnownError(164, "Requestrefused-noauthorization");
break; //[RFC5061]
// 165-260,Unassigned,
case 261:
var = new KnownError(261, "UnsupportedHMACIdentifier");
break; //[RFC4895]
// 262-65535,Unassigned,
}
try {
var.readBody(_body, blen);
Logger.Trace("variable type " + var.getType() + " name " + var.getName());
Logger.Trace("additional info " + var.ToString());
}
catch (SctpPacketFormatException ex) {
Logger.Error(ex.ToString());
}
if (_body.hasRemaining())
{
int mod = blen % 4;
if (mod != 0)
{
for (int pad = mod; pad < 4; pad++)
{
_body.GetByte();
}
}
}
return(var);
}