ObjXMPP  Artifact [934072be7a]

Artifact 934072be7a0862d3e27fd0feac55d3977a3aa5f05f860d396fc5bad30dad6fb0:

• File src/XMPPConnection.m — part of check-in [a618f77f45] at 2012-08-10 12:08:23 on branch trunk — Add very basic Stream Management (XEP-0198) support

  This implementation only counts incomming stanzas and
  sends ACKs on request.
  While basic this already allows servers to write
  messages to offline storage that were sent to,
  but never received by a client. (user: js, size: 26853) [annotate] [blame] [check-ins using]

/*
 * Copyright (c) 2010, 2011, 2012, Jonathan Schleifer <js@webkeks.org>
 * Copyright (c) 2011, 2012, Florian Zeitz <florob@babelmonkeys.de>
 *
 * https://webkeks.org/git/?p=objxmpp.git
 *
 * Permission to use, copy, modify, and/or distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice is present in all copies.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#ifdef HAVE_CONFIG_H
# include "config.h"
#endif

#define XMPP_CONNECTION_M

#include <assert.h>

#include <stringprep.h>
#include <idna.h>

#import <ObjOpenSSL/SSLSocket.h>
#import <ObjOpenSSL/SSLInvalidCertificateException.h>
#import <ObjOpenSSL/X509Certificate.h>

#import <ObjFW/OFInvalidArgumentException.h>

#import "XMPPConnection.h"
#import "XMPPCallback.h"
#import "XMPPSRVLookup.h"
#import "XMPPEXTERNALAuth.h"
#import "XMPPSCRAMAuth.h"
#import "XMPPPLAINAuth.h"
#import "XMPPStanza.h"
#import "XMPPJID.h"
#import "XMPPIQ.h"
#import "XMPPMessage.h"
#import "XMPPPresence.h"
#import "XMPPMulticastDelegate.h"
#import "XMPPExceptions.h"
#import "XMPPXMLElementBuilder.h"
#import "namespaces.h"

#import <ObjFW/macros.h>

@implementation XMPPConnection
+ connection
{
	return [[[self alloc] init] autorelease];
}

- init
{
	self = [super init];

	@try {
		sock = [[OFTCPSocket alloc] init];
		port = 5222;
		encrypted = NO;
		streamOpen = NO;
		delegates = [[XMPPMulticastDelegate alloc] init];
		callbacks = [[OFMutableDictionary alloc] init];
	} @catch (id e) {
		[self release];
		@throw e;
	}

	return self;
}

- (void)dealloc
{
	[sock release];
	[parser release];
	[elementBuilder release];
	[username release];
	[password release];
	[privateKeyFile release];
	[certificateFile release];
	[server release];
	[domain release];
	[resource release];
	[JID release];
	[delegates release];
	[callbacks release];
	[authModule release];

	[super dealloc];
}

- (void)setUsername: (OFString*)username_
{
	OFString *old = username;
	char *node;
	Stringprep_rc rc;

	if ((rc = stringprep_profile([username_ UTF8String], &node,
	    "SASLprep", 0)) != STRINGPREP_OK)
		@throw [XMPPStringPrepFailedException
		    exceptionWithClass: [self class]
			    connection: self
			       profile: @"SASLprep"
				string: username_];

	@try {
		username = [[OFString alloc] initWithUTF8String: node];
	} @finally {
		free(node);
	}

	[old release];
}

- (OFString*)username
{
	return [[username copy] autorelease];
}

- (void)setResource: (OFString*)resource_
{
	OFString *old = resource;
	char *res;
	Stringprep_rc rc;

	if ((rc = stringprep_profile([resource_ UTF8String], &res,
	    "Resourceprep", 0)) != STRINGPREP_OK)
		@throw [XMPPStringPrepFailedException
		    exceptionWithClass: [self class]
			    connection: self
			       profile: @"Resourceprep"
				string: resource_];

	@try {
		resource = [[OFString alloc] initWithUTF8String: res];
	} @finally {
		free(res);
	}

	[old release];
}

- (OFString*)resource
{
	return [[resource copy] autorelease];
}

- (void)setServer: (OFString*)server_
{
	OFString *old = server;
	server = [self XMPP_IDNAToASCII: server_];
	[old release];
}

- (OFString*)server
{
	return [[server copy] autorelease];
}

- (void)setDomain: (OFString*)domain_
{
	OFString *oldDomain = domain;
	OFString *oldDomainToASCII = domainToASCII;
	char *srv;
	Stringprep_rc rc;

	if ((rc = stringprep_profile([domain_ UTF8String], &srv,
	    "Nameprep", 0)) != STRINGPREP_OK)
		@throw [XMPPStringPrepFailedException
		    exceptionWithClass: [self class]
			    connection: self
			       profile: @"Nameprep"
				string: domain_];

	@try {
		domain = [[OFString alloc] initWithUTF8String: srv];
	} @finally {
		free(srv);
	}
	[oldDomain release];

	domainToASCII = [self XMPP_IDNAToASCII: domain];
	[oldDomainToASCII release];
}

- (OFString*)domain
{
	return [[domain copy] autorelease];
}

- (void)setPassword: (OFString*)password_
{
	OFString *old = password;
	char *pass;
	Stringprep_rc rc;

	if ((rc = stringprep_profile([password_ UTF8String], &pass,
	    "SASLprep", 0)) != STRINGPREP_OK)
		@throw [XMPPStringPrepFailedException
		    exceptionWithClass: [self class]
			    connection: self
			       profile: @"SASLprep"
				string: password_];

	@try {
		password = [[OFString alloc] initWithUTF8String: pass];
	} @finally {
		free(pass);
	}

	[old release];
}

- (OFString*)password
{
	return [[password copy] autorelease];
}

- (void)setPrivateKeyFile: (OFString*)file
{
	OF_SETTER(privateKeyFile, file, YES, YES)
}

- (OFString*)privateKeyFile
{
	OF_GETTER(privateKeyFile, YES)
}

- (void)setCertificateFile: (OFString*)file
{
	OF_SETTER(certificateFile, file, YES, YES)
}

- (OFString*)certificateFile
{
	OF_GETTER(certificateFile, YES)
}

- (void)connect
{
	OFAutoreleasePool *pool = [[OFAutoreleasePool alloc] init];
	XMPPSRVEntry *candidate = nil;
	XMPPSRVLookup *SRVLookup = nil;
	OFEnumerator *enumerator;

	if (server)
		[sock connectToHost: [self XMPP_IDNAToASCII: server]
			       port: port];
	else {
		@try {
			SRVLookup = [XMPPSRVLookup
			    lookupWithDomain: domainToASCII];
		} @catch (id e) {
		}

		enumerator = [SRVLookup objectEnumerator];

		/* Iterate over SRV records, if any */
		if ((candidate = [enumerator nextObject]) != nil) {
			do {
				@try {
					[sock connectToHost: [candidate target]
						       port: [candidate port]];
					break;
				} @catch (OFAddressTranslationFailedException
				    *e) {
				} @catch (OFConnectionFailedException *e) {
				}
			} while ((candidate = [enumerator nextObject]) != nil);
		} else
			/* No SRV records -> fall back to A / AAAA record */
			[sock connectToHost: domainToASCII
				       port: port];
	}

	[self XMPP_startStream];

	[pool release];
}

- (void)handleConnection
{
	char buffer[512];

	for (;;) {
		size_t length = [sock readIntoBuffer: buffer
					      length: 512];

		[self parseBuffer: buffer
			   length: length];

		if (length < 1)
			return;
	}
}

- (void)parseBuffer: (const char*)buffer
	     length: (size_t)length
{
	if (length < 1) {
		[delegates broadcastSelector: @selector(connectionWasClosed:)
				  withObject: self];
		return;
	}

	@try {
		[parser parseBuffer: buffer
			 length: length];
	} @catch (OFMalformedXMLException *e) {
		[self XMPP_sendStreamError: @"bad-format"
				      text: nil];
		[self close];
	}

	[oldParser release];
	[oldElementBuilder release];

	oldParser = nil;
	oldElementBuilder = nil;
}

- (OFTCPSocket*)socket
{
	return [[sock retain] autorelease];
}

- (BOOL)encryptionRequired
{
	return encryptionRequired;
}

- (void)setEncryptionRequired: (BOOL)required
{
	encryptionRequired = required;
}

- (BOOL)encrypted
{
	return encrypted;
}

- (BOOL)streamOpen
{
	return streamOpen;
}

- (BOOL)supportsRosterVersioning
{
	return supportsRosterVersioning;
}

- (BOOL)supportsStreamManagement
{
	return supportsStreamManagement;
}

- (BOOL)checkCertificateAndGetReason: (OFString**)reason
{
	X509Certificate *cert;
	OFDictionary *SANs;
	BOOL serviceSpecific = NO;

	@try {
		[sock verifyPeerCertificate];
	} @catch (SSLInvalidCertificateException *e) {
		if (reason != NULL)
			*reason = [[[e reason] copy] autorelease];

		return NO;
	}

	cert = [sock peerCertificate];
	SANs = [cert subjectAlternativeName];

	if ([[SANs objectForKey: @"otherName"]
		objectForKey: OID_SRVName] != nil ||
	     [SANs objectForKey: @"dNSName"] != nil ||
	     [SANs objectForKey: @"uniformResourceIdentifier"] != nil)
		serviceSpecific = YES;

	if ([cert hasSRVNameMatchingDomain: domainToASCII
				   service: @"xmpp-client"] ||
	    [cert hasDNSNameMatchingDomain: domainToASCII])
		return YES;

	if (!serviceSpecific &&
	    [cert hasCommonNameMatchingDomain: domainToASCII])
		return YES;

	return NO;
}

- (void)sendStanza: (OFXMLElement*)element
{
	[delegates broadcastSelector: @selector(connection:didSendElement:)
			  withObject: self
			  withObject: element];

	[sock writeString: [element XMLString]];
}

-	(void)sendIQ: (XMPPIQ*)iq
  withCallbackObject: (id)object
	    selector: (SEL)selector
{
	OFAutoreleasePool *pool;
	XMPPCallback *callback;

	if (![iq ID])
		[iq setID: [self generateStanzaID]];

	pool = [[OFAutoreleasePool alloc] init];
	callback = [XMPPCallback callbackWithCallbackObject: object
						   selector: selector];
	[callbacks setObject: callback
		      forKey: [iq ID]];
	[pool release];

	[self sendStanza: iq];
}

#ifdef OF_HAVE_BLOCKS
-      (void)sendIQ: (XMPPIQ*)iq
  withCallbackBlock: (xmpp_callback_block_t)block;
{
	OFAutoreleasePool *pool;
	XMPPCallback *callback;

	if (![iq ID])
		[iq setID: [self generateStanzaID]];

	pool = [[OFAutoreleasePool alloc] init];
	callback = [XMPPCallback callbackWithCallbackBlock: block];
	[callbacks setObject: callback
		      forKey: [iq ID]];
	[pool release];

	[self sendStanza: iq];
}
#endif

- (OFString*)generateStanzaID
{
	return [OFString stringWithFormat: @"objxmpp_%u", lastID++];
}

-    (void)parser: (OFXMLParser*)p
  didStartElement: (OFString*)name
       withPrefix: (OFString*)prefix
	namespace: (OFString*)ns
       attributes: (OFArray*)attributes
{
	OFEnumerator *enumerator;
	OFXMLAttribute *attribute;

	if (![name isEqual: @"stream"]) {
		// No dedicated stream error for this, may not even be XMPP
		[self close];
		[sock close];
		return;
	}

	if (![prefix isEqual: @"stream"]) {
		[self XMPP_sendStreamError: @"bad-namespace-prefix"
				      text: nil];
		return;
	}

	if (![ns isEqual: XMPP_NS_STREAM]) {
		[self XMPP_sendStreamError: @"invalid-namespace"
				      text: nil];
		return;
	}

	enumerator = [attributes objectEnumerator];
	while ((attribute = [enumerator nextObject]) != nil) {
		if ([[attribute name] isEqual: @"from"] &&
		    ![[attribute stringValue] isEqual: domain]) {
			[self XMPP_sendStreamError: @"invalid-from"
					      text: nil];
			return;
		}
		if ([[attribute name] isEqual: @"version"] &&
		    ![[attribute stringValue] isEqual: @"1.0"]) {
			[self XMPP_sendStreamError: @"unsupported-version"
					      text: nil];
			return;
		}
	}

	[parser setDelegate: elementBuilder];
}

- (void)elementBuilder: (OFXMLElementBuilder*)builder
       didBuildElement: (OFXMLElement*)element
{
	/* Ignore whitespace elements */
	if ([element name] == nil)
		return;

	[element setDefaultNamespace: XMPP_NS_CLIENT];
	[element setPrefix: @"stream"
	      forNamespace: XMPP_NS_STREAM];

	[delegates broadcastSelector: @selector(connection:didReceiveElement:)
			  withObject: self
			  withObject: element];

	if ([[element namespace] isEqual: XMPP_NS_CLIENT])
		[self XMPP_handleStanza: element];

	if ([[element namespace] isEqual: XMPP_NS_STREAM])
		[self XMPP_handleStream: element];

	if ([[element namespace] isEqual: XMPP_NS_STARTTLS])
		[self XMPP_handleTLS: element];

	if ([[element namespace] isEqual: XMPP_NS_SASL])
		[self XMPP_handleSASL: element];
}

- (void)elementBuilder: (OFXMLElementBuilder*)builder
  didNotExpectCloseTag: (OFString*)name
	    withPrefix: (OFString*)prefix
	     namespace: (OFString*)ns
{
	if (![name isEqual: @"stream"] || ![prefix isEqual: @"stream"] ||
	    ![ns isEqual: XMPP_NS_STREAM])
		@throw [OFMalformedXMLException
		    exceptionWithClass: [builder class]
				parser: nil];
	else {
		[self close];
	}
}

- (void)XMPP_startStream
{
	OFString *langString = @"";

	/* Make sure we don't get any old events */
	[parser setDelegate: nil];
	[elementBuilder setDelegate: nil];

	/*
	 * We can't release them now, as we are currently inside them. Release
	 * them the next time the parser returns.
	 */
	oldParser = parser;
	oldElementBuilder = elementBuilder;

	parser = [[OFXMLParser alloc] init];
	[parser setDelegate: self];

	elementBuilder = [[XMPPXMLElementBuilder alloc] init];
	[elementBuilder setDelegate: self];

	if (language != nil)
		langString = [OFString stringWithFormat: @"xml:lang='%@' ",
							 language];

	[sock writeFormat: @"<?xml version='1.0'?>\n"
			   @"<stream:stream to='%@' "
			   @"xmlns='" XMPP_NS_CLIENT @"' "
			   @"xmlns:stream='" XMPP_NS_STREAM @"' %@"
			   @"version='1.0'>", domain, langString];

	streamOpen = YES;
}

- (void)close
{
	if (streamOpen) {
		[sock writeString: @"</stream:stream>"];
		streamOpen = NO;
	}
}

- (void)XMPP_handleStanza: (OFXMLElement*)element
{
	if ([[element name] isEqual: @"iq"]) {
		[self XMPP_handleIQ: [XMPPIQ stanzaWithElement: element]];
		return;
	}

	if ([[element name] isEqual: @"message"]) {
		[self XMPP_handleMessage:
		    [XMPPMessage stanzaWithElement: element]];
		return;
	}

	if ([[element name] isEqual: @"presence"]) {
		[self XMPP_handlePresence:
		    [XMPPPresence stanzaWithElement: element]];
		return;
	}

	[self XMPP_sendStreamError: @"unsupported-stanza-type"
			      text: nil];
}


- (void)XMPP_handleStream: (OFXMLElement*)element
{
	if ([[element name] isEqual: @"features"]) {
		[self XMPP_handleFeatures: element];
		return;
	}

	if ([[element name] isEqual: @"error"]) {
		OFString *condition, *reason;
		[self close];
		[sock close]; // Remote has already closed his stream

		if ([element elementForName: @"bad-format"
				  namespace: XMPP_NS_XMPP_STREAM])
			condition = @"bad-format";
		else if ([element elementForName: @"bad-namespace-prefix"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"bad-namespace-prefix";
		else if ([element elementForName: @"conflict"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"conflict";
		else if ([element elementForName: @"connection-timeout"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"connection-timeout";
		else if ([element elementForName: @"host-gone"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"host-gone";
		else if ([element elementForName: @"host-unknown"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"host-unknown";
		else if ([element elementForName: @"improper-addressing"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"improper-addressing";
		else if ([element elementForName: @"internal-server-error"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"internal-server-error";
		else if ([element elementForName: @"invalid-from"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"invalid-from";
		else if ([element elementForName: @"invalid-namespace"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"invalid-namespace";
		else if ([element elementForName: @"invalid-xml"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"invalid-xml";
		else if ([element elementForName: @"not-authorized"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"not-authorized";
		else if ([element elementForName: @"not-well-formed"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"not-well-formed";
		else if ([element elementForName: @"policy-violation"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"policy-violation";
		else if ([element elementForName: @"remote-connection-failed"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"remote-connection-failed";
		else if ([element elementForName: @"reset"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"reset";
		else if ([element elementForName: @"resource-constraint"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"resource-constraint";
		else if ([element elementForName: @"restricted-xml"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"restricted-xml";
		else if ([element elementForName: @"see-other-host"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"see-other-host";
		else if ([element elementForName: @"system-shutdown"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"system-shutdown";
		else if ([element elementForName: @"undefined-condition"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"undefined-condition";
		else if ([element elementForName: @"unsupported-encoding"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"unsupported-encoding";
		else if ([element elementForName: @"unsupported-feature"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"unsupported-feature";
		else if ([element elementForName: @"unsupported-stanza-type"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"unsupported-stanza-type";
		else if ([element elementForName: @"unsupported-version"
				       namespace: XMPP_NS_XMPP_STREAM])
			condition = @"unsupported-version";
		else
			condition = @"undefined";

		reason = [[element
		    elementForName: @"text"
			 namespace: XMPP_NS_XMPP_STREAM] stringValue];

		@throw [XMPPStreamErrorException
		    exceptionWithClass: [self class]
			    connection: self
			     condition: condition
				reason: reason];
		return;
	}

	assert(0);
}

- (void)XMPP_handleTLS: (OFXMLElement*)element
{
	if ([[element name] isEqual: @"proceed"]) {
		/* FIXME: Catch errors here */
		SSLSocket *newSock;

		[delegates broadcastSelector: @selector(
						  connectionWillUpgradeToTLS:)
				  withObject: self];

		newSock = [[SSLSocket alloc] initWithSocket: sock
					     privateKeyFile: privateKeyFile
					    certificateFile: certificateFile];
		[sock release];
		sock = newSock;

		encrypted = YES;

		[delegates broadcastSelector: @selector(
						  connectionDidUpgradeToTLS:)
				  withObject: self];

		/* Stream restart */
		[self XMPP_startStream];

		return;
	}

	if ([[element name] isEqual: @"failure"])
		/* TODO: Find/create an exception to throw here */
		@throw [OFException exceptionWithClass: [self class]];

	assert(0);
}

- (void)XMPP_handleSASL: (OFXMLElement*)element
{
	if ([[element name] isEqual: @"challenge"]) {
		OFXMLElement *responseTag;
		OFDataArray *challenge = [OFDataArray
		    dataArrayWithBase64EncodedString: [element stringValue]];
		OFDataArray *response = [authModule
		    continueWithData: challenge];

		responseTag = [OFXMLElement elementWithName: @"response"
						  namespace: XMPP_NS_SASL];
		if (response) {
			if ([response count] == 0)
				[responseTag setStringValue: @"="];
			else
				[responseTag setStringValue:
				    [response stringByBase64Encoding]];
		}

		[self sendStanza: responseTag];
		return;
	}

	if ([[element name] isEqual: @"success"]) {
		[authModule continueWithData: [OFDataArray
		    dataArrayWithBase64EncodedString: [element stringValue]]];

		[delegates broadcastSelector: @selector(
						  connectionWWasAuthenticated:)
				  withObject: self];

		/* Stream restart */
		[self XMPP_startStream];

		return;
	}

	if ([[element name] isEqual: @"failure"]) {
		of_log(@"Auth failed!");
		// FIXME: Do more parsing/handling
		@throw [XMPPAuthFailedException
		    exceptionWithClass: [self class]
			    connection: self
				reason: [element XMLString]];
	}

	assert(0);
}

- (void)XMPP_handleIQ: (XMPPIQ*)iq
{
	BOOL handled = NO;
	XMPPCallback *callback;

	if ((callback = [callbacks objectForKey: [iq ID]])) {
		[callback runWithIQ: iq
			 connection: self];
		[callbacks removeObjectForKey: [iq ID]];
		return;
	}

	handled = [delegates broadcastSelector: @selector(
						    connection:didReceiveIQ:)
				    withObject: self
				    withObject: iq];

	if (!handled && ![[iq type] isEqual: @"error"] &&
	    ![[iq type] isEqual: @"result"]) {
		[self sendStanza: [iq errorIQWithType: @"cancel"
					    condition: @"service-unavailable"]];
	}
}

- (void)XMPP_handleMessage: (XMPPMessage*)message
{
	[delegates broadcastSelector: @selector(connection:didReceiveMessage:)
			  withObject: self
			  withObject: message];
}

- (void)XMPP_handlePresence: (XMPPPresence*)presence
{
	[delegates broadcastSelector: @selector(connection:didReceivePresence:)
			  withObject: self
			  withObject: presence];
}

- (void)XMPP_handleFeatures: (OFXMLElement*)element
{
	OFXMLElement *starttls = [element elementForName: @"starttls"
					       namespace: XMPP_NS_STARTTLS];
	OFXMLElement *bind = [element elementForName: @"bind"
					   namespace: XMPP_NS_BIND];
	OFXMLElement *session = [element elementForName: @"session"
					      namespace: XMPP_NS_SESSION];
	OFXMLElement *mechs = [element elementForName: @"mechanisms"
					    namespace: XMPP_NS_SASL];
	OFMutableSet *mechanisms = [OFMutableSet set];

	if (starttls != nil) {
		[self sendStanza:
		    [OFXMLElement elementWithName: @"starttls"
					namespace: XMPP_NS_STARTTLS]];
		return;
	}

	if (encryptionRequired && !encrypted)
		/* TODO: Find/create an exception to throw here */
		@throw [OFException exceptionWithClass: [self class]];

	if ([element elementForName: @"ver"
			  namespace: XMPP_NS_ROSTERVER] != nil)
		supportsRosterVersioning = YES;

	if ([element elementForName: @"sm"
			  namespace: XMPP_NS_SM] != nil)
		supportsStreamManagement = YES;

	if (mechs != nil) {
		OFEnumerator *enumerator;
		OFXMLElement *mech;

		enumerator = [[mechs children] objectEnumerator];
		while ((mech = [enumerator nextObject]) != nil)
			[mechanisms addObject: [mech stringValue]];

		if (privateKeyFile && certificateFile &&
		    [mechanisms containsObject: @"EXTERNAL"]) {
			authModule = [[XMPPEXTERNALAuth alloc] init];
			[self XMPP_sendAuth: @"EXTERNAL"];
			return;
		}

		if ([mechanisms containsObject: @"SCRAM-SHA-1-PLUS"]) {
			authModule = [[XMPPSCRAMAuth alloc]
			    initWithAuthcid: username
				   password: password
				 connection: self
				       hash: [OFSHA1Hash class]
			      plusAvailable: YES];
			[self XMPP_sendAuth: @"SCRAM-SHA-1-PLUS"];
			return;
		}

		if ([mechanisms containsObject: @"SCRAM-SHA-1"]) {
			authModule = [[XMPPSCRAMAuth alloc]
			    initWithAuthcid: username
				   password: password
				 connection: self
				       hash: [OFSHA1Hash class]
			      plusAvailable: NO];
			[self XMPP_sendAuth: @"SCRAM-SHA-1"];
			return;
		}

		if ([mechanisms containsObject: @"PLAIN"] && encrypted) {
			authModule = [[XMPPPLAINAuth alloc]
			    initWithAuthcid: username
				   password: password];
			[self XMPP_sendAuth: @"PLAIN"];
			return;
		}

		assert(0);
	}

	if (session != nil)
		needsSession = YES;

	if (bind != nil) {
		[self XMPP_sendResourceBind];
		return;
	}

	assert(0);
}

- (void)XMPP_sendAuth: (OFString*)authName
{
	OFXMLElement *authTag;
	OFDataArray *initialMessage = [authModule initialMessage];

	authTag = [OFXMLElement elementWithName: @"auth"
				      namespace: XMPP_NS_SASL];
	[authTag addAttributeWithName: @"mechanism"
			  stringValue: authName];
	if (initialMessage) {
		if ([initialMessage count] == 0)
			[authTag setStringValue: @"="];
		else
			[authTag setStringValue:
			    [initialMessage stringByBase64Encoding]];
	}

	[self sendStanza: authTag];
}

- (void)XMPP_sendResourceBind
{
	XMPPIQ *iq;
	OFXMLElement *bind;

	iq = [XMPPIQ IQWithType: @"set"
			     ID: [self generateStanzaID]];

	bind = [OFXMLElement elementWithName: @"bind"
				   namespace: XMPP_NS_BIND];

	if (resource != nil)
		[bind addChild: [OFXMLElement elementWithName: @"resource"
						    namespace: XMPP_NS_BIND
						  stringValue: resource]];

	[iq addChild: bind];

	[self		sendIQ: iq
	    withCallbackObject: self
		      selector: @selector(XMPP_handleResourceBindForConnection:
				    withIQ:)];
}

- (void)XMPP_sendStreamError: (OFString*)condition
			text: (OFString*)text
{
	OFXMLElement *error = [OFXMLElement
	    elementWithName: @"error"
		  namespace: XMPP_NS_STREAM];
	[error setPrefix: @"stream"
	    forNamespace: XMPP_NS_STREAM];
	[error addChild: [OFXMLElement elementWithName: condition
					     namespace: XMPP_NS_XMPP_STREAM]];
	if (text)
		[error addChild: [OFXMLElement
		    elementWithName: @"text"
			  namespace: XMPP_NS_XMPP_STREAM
			stringValue: text]];
	[parser setDelegate: nil];
	[self sendStanza: error];
	[self close];
}

- (void)XMPP_handleResourceBindForConnection: (XMPPConnection*)connection
				      withIQ: (XMPPIQ*)iq
{
	OFXMLElement *bindElement;
	OFXMLElement *jidElement;

	assert([[iq type] isEqual: @"result"]);

	bindElement = [iq elementForName: @"bind"
			       namespace: XMPP_NS_BIND];

	assert(bindElement != nil);

	jidElement = [bindElement elementForName: @"jid"
				       namespace: XMPP_NS_BIND];
	JID = [[XMPPJID alloc] initWithString: [jidElement stringValue]];

	if (needsSession) {
		[self XMPP_sendSession];
		return;
	}

	[delegates broadcastSelector: @selector(connection:wasBoundToJID:)
			  withObject: self
			  withObject: JID];
}

- (void)XMPP_sendSession
{
	XMPPIQ *iq;

	iq = [XMPPIQ IQWithType: @"set"
			     ID: [self generateStanzaID]];
	[iq addChild: [OFXMLElement elementWithName: @"session"
					  namespace: XMPP_NS_SESSION]];
	[self		sendIQ: iq
	    withCallbackObject: self
		      selector: @selector(
				    XMPP_handleSessionForConnection:withIQ:)];
}

- (void)XMPP_handleSessionForConnection: (XMPPConnection*)connection
				 withIQ: (XMPPIQ*)iq
{
	if (![[iq type] isEqual: @"result"])
		assert(0);

	[delegates broadcastSelector: @selector(connection:wasBoundToJID:)
			  withObject: self
			  withObject: JID];
}

- (OFString*)XMPP_IDNAToASCII: (OFString*)domain_
{
	OFString *ret;
	char *cDomain;
	Idna_rc rc;

	if ((rc = idna_to_ascii_8z([domain_ UTF8String],
	    &cDomain, IDNA_USE_STD3_ASCII_RULES)) != IDNA_SUCCESS)
		@throw [XMPPIDNATranslationFailedException
		    exceptionWithClass: [self class]
			    connection: self
			     operation: @"ToASCII"
				string: domain_];

	@try {
		ret = [[OFString alloc] initWithUTF8String: cDomain];
	} @finally {
		free(cDomain);
	}

	return ret;
}

- (XMPPJID*)JID
{
	return [[JID copy] autorelease];
}

- (void)setPort: (uint16_t)port_
{
	port = port_;
}

- (uint16_t)port
{
	return port;
}

- (void)setDataStorage: (id <XMPPStorage>)dataStorage_
{
	if (streamOpen)
		@throw [OFInvalidArgumentException
		    exceptionWithClass: [self class]];

	dataStorage = dataStorage_;
}

- (id <XMPPStorage>)dataStorage
{
	return dataStorage;
}

- (void)setLanguage: (OFString*)language_
{
	OF_SETTER(language, language_, YES, YES)
}

- (OFString*)language
{
	OF_GETTER(language, YES)
}

- (void)addDelegate: (id <XMPPConnectionDelegate>)delegate
{
	[delegates addDelegate: delegate];
}

- (void)removeDelegate: (id <XMPPConnectionDelegate>)delegate
{
	[delegates removeDelegate: delegate];
}

- (XMPPMulticastDelegate*)XMPP_delegates
{
	return delegates;
}
@end