/**
* Notifies this <tt>ResponseCollector</tt> that a STUN response described by the specified
* <tt>StunResponseEvent</tt> has been received.
*
* @param event the <tt>StunResponseEvent</tt> which describes the received STUN response
* @see ResponseCollector#processResponse(StunResponseEvent)
*/
@Override
public void processResponse(StunResponseEvent event) {
TransactionID transactionID = event.getTransactionID();
logger.finest("Received a message: tranid= " + transactionID);
logger.finest("localCand= " + hostCandidate);
/*
* Clean up for the purposes of the workaround which determines the STUN
* Request to which a STUN Response responds.
*/
synchronized (requests) {
requests.remove(transactionID);
}
// At long last, do start handling the received STUN Response.
Response response = event.getResponse();
Request request = event.getRequest();
boolean completedResolvingCandidate = true;
try {
if (response.isSuccessResponse()) {
// Authentication and Message-Integrity Mechanisms
if (request.containsAttribute(Attribute.MESSAGE_INTEGRITY)) {
MessageIntegrityAttribute messageIntegrityAttribute =
(MessageIntegrityAttribute) response.getAttribute(Attribute.MESSAGE_INTEGRITY);
/*
* RFC 5389: If MESSAGE-INTEGRITY was absent, the response
* MUST be discarded, as if it was never received.
*/
if (messageIntegrityAttribute == null) return;
UsernameAttribute usernameAttribute =
(UsernameAttribute) request.getAttribute(Attribute.USERNAME);
/*
* For a request or indication message, the agent MUST
* include the USERNAME and MESSAGE-INTEGRITY attributes in
* the message.
*/
if (usernameAttribute == null) return;
if (!harvester
.getStunStack()
.validateMessageIntegrity(
messageIntegrityAttribute,
LongTermCredential.toString(usernameAttribute.getUsername()),
!request.containsAttribute(Attribute.REALM)
&& !request.containsAttribute(Attribute.NONCE),
event.getRawMessage())) return;
}
processSuccess(response, request, transactionID);
} else {
ErrorCodeAttribute errorCodeAttr =
(ErrorCodeAttribute) response.getAttribute(Attribute.ERROR_CODE);
if ((errorCodeAttr != null) && (errorCodeAttr.getErrorClass() == 4)) {
try {
switch (errorCodeAttr.getErrorNumber()) {
case 1: // 401 Unauthorized
if (processUnauthorized(response, request, transactionID))
completedResolvingCandidate = false;
break;
case 38: // 438 Stale Nonce
if (processStaleNonce(response, request, transactionID))
completedResolvingCandidate = false;
break;
}
} catch (StunException sex) {
completedResolvingCandidate = true;
}
}
if (completedResolvingCandidate && processErrorOrFailure(response, request, transactionID))
completedResolvingCandidate = false;
}
} finally {
if (completedResolvingCandidate) completedResolvingCandidate(request, response);
}
}
/**
* Notifies this <tt>StunCandidateHarvest</tt> that a specific STUN <tt>Request</tt> has been
* challenged for a long-term credential (as the short-term credential mechanism does not utilize
* challenging) in a specific <tt>realm</tt> and with a specific <tt>nonce</tt>.
*
* @param realm the realm in which the specified STUN <tt>Request</tt> has been challenged for a
* long-term credential
* @param nonce the nonce with which the specified STUN <tt>Request</tt> has been challenged for a
* long-term credential
* @param request the STUN <tt>Request</tt> which has been challenged for a long-term credential
* @param requestTransactionID the <tt>TransactionID</tt> of <tt>request</tt> because
* <tt>request</tt> only has it as a <tt>byte</tt> array and <tt>TransactionID</tt> is
* required for the <tt>applicationData</tt> property value
* @return <tt>true</tt> if the challenge has been processed and this
* <tt>StunCandidateHarvest</tt> is to continue processing STUN <tt>Response</tt>s; otherwise,
* <tt>false</tt>
* @throws StunException if anything goes wrong while processing the challenge
*/
private boolean processChallenge(
byte[] realm, byte[] nonce, Request request, TransactionID requestTransactionID)
throws StunException {
UsernameAttribute usernameAttribute =
(UsernameAttribute) request.getAttribute(Attribute.USERNAME);
if (usernameAttribute == null) {
if (longTermCredentialSession == null) {
LongTermCredential longTermCredential = harvester.createLongTermCredential(this, realm);
if (longTermCredential == null) {
// The long-term credential mechanism is not being utilized.
return false;
} else {
longTermCredentialSession = new LongTermCredentialSession(longTermCredential, realm);
harvester
.getStunStack()
.getCredentialsManager()
.registerAuthority(longTermCredentialSession);
}
} else {
/*
* If we're going to use the long-term credential to retry the
* request, the long-term credential should be for the request
* in terms of realm.
*/
if (!longTermCredentialSession.realmEquals(realm)) return false;
}
} else {
/*
* If we sent a USERNAME in our request, then we had the long-term
* credential at the time we sent the request in question.
*/
if (longTermCredentialSession == null) return false;
else {
/*
* If we're going to use the long-term credential to retry the
* request, the long-term credential should be for the request
* in terms of username.
*/
if (!longTermCredentialSession.usernameEquals(usernameAttribute.getUsername()))
return false;
else {
// And it terms of realm, of course.
if (!longTermCredentialSession.realmEquals(realm)) return false;
}
}
}
/*
* The nonce is either becoming known for the first time or being
* updated after the old one has gone stale.
*/
longTermCredentialSession.setNonce(nonce);
Request retryRequest = createRequestToRetry(request);
TransactionID retryRequestTransactionID = null;
if (retryRequest != null) {
if (requestTransactionID != null) {
Object applicationData = requestTransactionID.getApplicationData();
if (applicationData != null) {
byte[] retryRequestTransactionIDAsBytes = retryRequest.getTransactionID();
retryRequestTransactionID =
(retryRequestTransactionIDAsBytes == null)
? TransactionID.createNewTransactionID()
: TransactionID.createTransactionID(
harvester.getStunStack(), retryRequestTransactionIDAsBytes);
retryRequestTransactionID.setApplicationData(applicationData);
}
}
retryRequestTransactionID = sendRequest(retryRequest, false, retryRequestTransactionID);
}
return (retryRequestTransactionID != null);
}