/**
* Tries to obtain a mapped/public address for the specified port (possibly by executing a STUN
* query).
*
* @param dst the destination that we'd like to use this address with.
* @param port the port whose mapping we are interested in.
* @return a public address corresponding to the specified port or null if all attempts to
* retrieve such an address have failed.
* @throws IOException if an error occurs while stun4j is using sockets.
* @throws BindException if the port is already in use.
*/
public InetSocketAddress getPublicAddressFor(InetAddress dst, int port)
throws IOException, BindException {
if (!useStun || (dst instanceof Inet6Address)) {
logger.debug(
"Stun is disabled for destination "
+ dst
+ ", skipping mapped address recovery (useStun="
+ useStun
+ ", IPv6@="
+ (dst instanceof Inet6Address)
+ ").");
// we'll still try to bind though so that we could notify the caller
// if the port has been taken already.
DatagramSocket bindTestSocket = new DatagramSocket(port);
bindTestSocket.close();
// if we're here then the port was free.
return new InetSocketAddress(getLocalHost(dst), port);
}
StunAddress mappedAddress = queryStunServer(port);
InetSocketAddress result = null;
if (mappedAddress != null) result = mappedAddress.getSocketAddress();
else {
// Apparently STUN failed. Let's try to temporarily disble it
// and use algorithms in getLocalHost(). ... We should probably
// eveng think about completely disabling stun, and not only
// temporarily.
// Bug report - John J. Barton - IBM
InetAddress localHost = getLocalHost(dst);
result = new InetSocketAddress(localHost, port);
}
if (logger.isDebugEnabled())
logger.debug("Returning mapping for port:" + port + " as follows: " + result);
return result;
}
/** The diagnostics code itself. */
public void run() {
logger.debug("Started a diag kit for entry: " + addressEntry);
// implements the algorithm from AssigningAddressPreferences.png
setDiagnosticsStatus(this.DIAGNOSTICS_STATUS_DISOVERING_CONFIG);
InetAddress address = addressEntry.getInetAddress();
// is this an ipv6 address
if (addressEntry.isIPv6()) {
if (addressEntry.isLinkLocal()) {
addressEntry.setAddressPreference(ADDR_PREF_LOCAL_IPV6);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
if (addressEntry.is6to4()) {
// right now we don't support these. we should though ... one day
addressEntry.setAddressPreference(AddressPreference.MIN);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
// if we get here then we are a globally routable ipv6 addr
addressEntry.setAddressPreference(ADDR_PREF_GLOBAL_IPV6);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_COMPLETED);
// should do some connectivity testing here and proceed with firewall
// discovery but since stun4j does not support ipv6 yet, this too
// will happen another day.
return;
}
// from now on we're only dealing with IPv4
if (addressEntry.isIPv4LinkLocalAutoconf()) {
// not sure whether these are used for anything.
addressEntry.setAddressPreference(AddressPreference.MIN);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
// first try and see what we can infer from just looking at the
// address
if (addressEntry.isLinkLocalIPv4Address()) {
addressEntry.setAddressPreference(ADDR_PREF_PRIVATE_IPV4);
} else {
// public address
addressEntry.setAddressPreference(ADDR_PREF_GLOBAL_IPV4);
}
if (!useStun) {
// if we're configured not to run stun - we're done.
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
// start stunning
for (int i = 0; i < bindRetries; i++) {
StunAddress localStunAddress = new StunAddress(address, 1024 + (int) (Math.random() * 64512));
try {
stunClient = new StunClient(localStunAddress);
stunClient.start();
logger.debug("Successfully started StunClient for " + localStunAddress + ".");
break;
} catch (StunException ex) {
if (ex.getCause() instanceof SocketException && i < bindRetries) {
logger.debug("Failed to bind to " + localStunAddress + ". Retrying ...");
logger.debug("Exception was ", ex);
continue;
}
logger.error(
"Failed to start a stun client for address entry ["
+ addressEntry.toString()
+ "]:"
+ localStunAddress.getPort()
+ ". Ceasing attempts",
ex);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
}
// De Stun Test I
StunMessageEvent event = null;
try {
event = stunClient.doStunTestI(primaryStunServerAddress);
} catch (StunException ex) {
logger.error("Failed to perform STUN Test I for address entry" + addressEntry.toString(), ex);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
if (event == null) {
// didn't get a response - we either don't have connectivity or the
// server is down
/** @todo if possible try another stun server here. we should support multiple stun servers */
logger.debug("There seems to be no inet connectivity for " + addressEntry);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
logger.debug("stun test 1 failed");
return;
}
// the moment of the truth - are we behind a NAT?
boolean isPublic;
Message stunResponse = event.getMessage();
Attribute mappedAttr = stunResponse.getAttribute(Attribute.MAPPED_ADDRESS);
StunAddress mappedAddrFromTestI = ((MappedAddressAttribute) mappedAttr).getAddress();
Attribute changedAddressAttributeFromTestI =
stunResponse.getAttribute(Attribute.CHANGED_ADDRESS);
StunAddress secondaryStunServerAddress =
((ChangedAddressAttribute) changedAddressAttributeFromTestI).getAddress();
/**
* @todo verify whether the stun server returned the same address for the primary and secondary
* server and act accordingly
*/
if (mappedAddrFromTestI == null) {
logger.error(
"Stun Server did not return a mapped address for entry " + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
return;
}
if (mappedAddrFromTestI.equals(event.getSourceAccessPoint().getAddress())) {
isPublic = true;
} else {
isPublic = false;
}
// do STUN Test II
try {
event = stunClient.doStunTestII(primaryStunServerAddress);
} catch (StunException ex) {
logger.error(
"Failed to perform STUN Test II for address entry" + addressEntry.toString(), ex);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
logger.debug("stun test 2 failed");
return;
}
if (event != null) {
logger.error("Secondary STUN server is down" + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
// might mean that either the secondary stun server is down
// or that we are behind a restrictive firewall. Let's find out
// which.
try {
event = stunClient.doStunTestI(secondaryStunServerAddress);
logger.debug("stun test 1 succeeded with s server 2");
} catch (StunException ex) {
logger.error("Failed to perform STUN Test I for address entry" + addressEntry.toString(), ex);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
if (event == null) {
// secondary stun server is down
logger.error("Secondary STUN server is down" + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
// we are at least behind a port restricted nat
stunResponse = event.getMessage();
mappedAttr = stunResponse.getAttribute(Attribute.MAPPED_ADDRESS);
StunAddress mappedAddrFromSecServer = ((MappedAddressAttribute) mappedAttr).getAddress();
if (!mappedAddrFromTestI.equals(mappedAddrFromSecServer)) {
// secondary stun server is down
logger.debug("We are behind a symmetric nat" + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
// now let's run test III so that we could guess whether or not we're
// behind a port restricted nat/fw or simply a restricted one.
try {
event = stunClient.doStunTestIII(primaryStunServerAddress);
logger.debug("stun test 3 succeeded with s server 1");
} catch (StunException ex) {
logger.error(
"Failed to perform STUN Test III for address entry" + addressEntry.toString(), ex);
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
if (event == null) {
logger.debug("We are behind a port restricted NAT or fw" + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
return;
}
logger.debug("We are behind a restricted NAT or fw" + addressEntry.toString());
setDiagnosticsStatus(DIAGNOSTICS_STATUS_TERMINATED);
stunClient.shutDown();
}