/**
* Gets the <tt>TransportAddress</tt> specified in the XOR-MAPPED-ADDRESS attribute of a specific
* <tt>Response</tt>.
*
* @param response the <tt>Response</tt> from which the XOR-MAPPED-ADDRESS attribute is to be
* retrieved and its <tt>TransportAddress</tt> value is to be returned
* @return the <tt>TransportAddress</tt> specified in the XOR-MAPPED-ADDRESS attribute of
* <tt>response</tt>
*/
protected TransportAddress getMappedAddress(Response response) {
Attribute attribute = response.getAttribute(Attribute.XOR_MAPPED_ADDRESS);
if (attribute instanceof XorMappedAddressAttribute) {
return ((XorMappedAddressAttribute) attribute).getAddress(response.getTransactionID());
}
// old STUN servers (RFC3489) send MAPPED-ADDRESS address
attribute = response.getAttribute(Attribute.MAPPED_ADDRESS);
if (attribute instanceof MappedAddressAttribute) {
return ((MappedAddressAttribute) attribute).getAddress();
} else return null;
}
/**
* Notifies this <tt>StunCandidateHarvest</tt> that a specific STUN <tt>Response</tt> has been
* received and it challenges a specific STUN <tt>Request</tt> for a long-term credential (as the
* short-term credential mechanism does not utilize challenging).
*
* @param response the STUN <tt>Response</tt> which has been received
* @param request the STUN <tt>Request</tt> to which <tt>response</tt> responds and which it
* challenges for a long-term credential
* @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>
* @param transactionID the <tt>TransactionID</tt> of <tt>response</tt> and <tt>request</tt>
* because <tt>response</tt> and <tt>request</tt> only have it as a <tt>byte</tt> array and
* <tt>TransactionID</tt> is required for the <tt>applicationData</tt> property value
* @throws StunException if anything goes wrong while processing the challenge
*/
private boolean processChallenge(Response response, Request request, TransactionID transactionID)
throws StunException {
boolean retried = false;
if (response.getAttributeCount() > 0) {
/*
* The response SHOULD NOT contain a USERNAME or
* MESSAGE-INTEGRITY attribute.
*/
char[] excludedResponseAttributeTypes =
new char[] {Attribute.USERNAME, Attribute.MESSAGE_INTEGRITY};
boolean challenge = true;
for (char excludedResponseAttributeType : excludedResponseAttributeTypes) {
if (response.containsAttribute(excludedResponseAttributeType)) {
challenge = false;
break;
}
}
if (challenge) {
// This response MUST include a REALM value.
RealmAttribute realmAttribute = (RealmAttribute) response.getAttribute(Attribute.REALM);
if (realmAttribute == null) challenge = false;
else {
// The response MUST include a NONCE.
NonceAttribute nonceAttribute = (NonceAttribute) response.getAttribute(Attribute.NONCE);
if (nonceAttribute == null) challenge = false;
else {
retried =
processChallenge(
realmAttribute.getRealm(), nonceAttribute.getNonce(), request, transactionID);
}
}
}
}
return retried;
}
/**
* 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);
}
}