/****************************************************************************

**

** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

** All rights reserved.

** Contact: Nokia Corporation (qt-info@nokia.com)

**

** This file is part of the Qt3Support module of the Qt Toolkit.

**

** $QT_BEGIN_LICENSE:LGPL$

** No Commercial Usage

** This file contains pre-release code and may not be distributed.

** You may use this file in accordance with the terms and conditions

** contained in the Technology Preview License Agreement accompanying

** this package.

**

** GNU Lesser General Public License Usage

** Alternatively, this file may be used under the terms of the GNU Lesser

** General Public License version 2.1 as published by the Free Software

** Foundation and appearing in the file LICENSE.LGPL included in the

** packaging of this file.  Please review the following information to

** ensure the GNU Lesser General Public License version 2.1 requirements

** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.

**

** In addition, as a special exception, Nokia gives you certain additional

** rights.  These rights are described in the Nokia Qt LGPL Exception

** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.

**

** If you have questions regarding the use of this file, please contact

** Nokia at qt-info@nokia.com.

**

**

**

**

**

**

**

**

** $QT_END_LICENSE$

**

****************************************************************************/

#include "qplatformdefs.h"

#include "qbytearray.h"

#if defined(Q_OS_WIN32) || defined(Q_OS_WINCE) || defined(Q_OS_CYGWIN)

# include "qt_windows.h"

#else

# include <sys/types.h>

# include <netinet/in.h>

# include <arpa/nameser.h>

# include <resolv.h>

extern "C" int res_init();

#endif

// POSIX Large File Support redefines open -> open64

#if defined(open)

# undef open

#endif

// POSIX Large File Support redefines truncate -> truncate64

#if defined(truncate)

# undef truncate

#endif

// Solaris redefines connect -> __xnet_connect with _XOPEN_SOURCE_EXTENDED.

#if defined(connect)

# undef connect

#endif

// UnixWare 7 redefines socket -> _socket

#if defined(socket)

# undef socket

#endif

#include "q3dns.h"

#ifndef QT_NO_DNS

#include "qdatetime.h"

#include "q3dict.h"

#include "q3ptrlist.h"

#include "qstring.h"

#include "qtimer.h"

#include "qapplication.h"

#include "q3ptrvector.h"

#include "q3strlist.h"

#include "q3ptrdict.h"

#include "qfile.h"

#include "qtextstream.h"

#include "q3socketdevice.h"

#include "q3cleanuphandler.h"

#include <limits.h>

QT_BEGIN_NAMESPACE

//#define Q3DNS_DEBUG

static Q_UINT16 theId; // ### seeded started by now()

static QDateTime * originOfTime = 0;

static Q3CleanupHandler<QDateTime> q3dns_cleanup_time;

static Q_UINT32 now()

{

    if ( originOfTime )

	return originOfTime->secsTo( QDateTime::currentDateTime() );

    originOfTime = new QDateTime( QDateTime::currentDateTime() );

    theId = originOfTime->time().msec() * 60 + originOfTime->time().second();

    q3dns_cleanup_time.add( &originOfTime );

    return 0;

}

static Q3PtrList<QHostAddress> * theNs = 0;

static Q3StrList * theDomains = 0;

static bool ipv6support = false;

class Q3DnsPrivate {

public:

    Q3DnsPrivate() : queryTimer( 0 ), noNames(false)

    {

#if defined(Q_DNS_SYNCHRONOUS)

#if defined(Q_OS_UNIX)

	noEventLoop = qApp==0 || qApp->loopLevel()==0;

#else

	noEventLoop = false;

#endif

#endif

    }

    ~Q3DnsPrivate()

    {

	delete queryTimer;

    }

private:

    QTimer * queryTimer;

    bool noNames;

#if defined(Q_DNS_SYNCHRONOUS)

    bool noEventLoop;

#endif

    friend class Q3Dns;

    friend class Q3DnsAnswer;

};

class Q3DnsRR;

class Q3DnsDomain;

// Q3DnsRR is the class used to store a single RR.  Q3DnsRR can store

// all of the supported RR types.  a Q3DnsRR is always cached.

// Q3DnsRR is mostly constructed from the outside.  a but hacky, but

// permissible since the entire class is internal.

class Q3DnsRR {

public:

    Q3DnsRR( const QString & label );

    ~Q3DnsRR();

public:

    Q3DnsDomain * domain;

    Q3Dns::RecordType t;

    bool nxdomain;

    bool current;

    Q_UINT32 expireTime;

    Q_UINT32 deleteTime;

    // somewhat space-wasting per-type data

    // a / aaaa

    QHostAddress address;

    // cname / mx / srv / ptr

    QString target;

    // mx / srv

    Q_UINT16 priority;

    // srv

    Q_UINT16 weight;

    Q_UINT16 port;

    // txt

    QString text; // could be overloaded into target...

private:

};

class Q3DnsDomain {

public:

    Q3DnsDomain( const QString & label );

    ~Q3DnsDomain();

    static void add( const QString & label, Q3DnsRR * );

    static Q3PtrList<Q3DnsRR> * cached( const Q3Dns * );

    void take( Q3DnsRR * );

    void sweep( Q_UINT32 thisSweep );

    bool isEmpty() const { return rrs == 0 || rrs->isEmpty(); }

    QString name() const { return l; }

public:

    QString l;

    Q3PtrList<Q3DnsRR> * rrs;

};

class Q3DnsQuery: public QTimer { // this inheritance is a very evil hack

public:

    Q3DnsQuery():

	id( 0 ), t( Q3Dns::None ), step(0), started(0),

	dns( new Q3PtrDict<void>(17) ) {}

    ~Q3DnsQuery() { delete dns; }

    Q_UINT16 id;

    Q3Dns::RecordType t;

    QString l;

    uint step;

    Q_UINT32 started;

    Q3PtrDict<void> * dns;

};

class Q3DnsAnswer {

public:

    Q3DnsAnswer( Q3DnsQuery * );

    Q3DnsAnswer( const QByteArray &, Q3DnsQuery * );

    ~Q3DnsAnswer();

    void parse();

    void notify();

    bool ok;

private:

    Q3DnsQuery * query;

    Q_UINT8 * answer;

    int size;

    int pp;

    Q3PtrList<Q3DnsRR> * rrs;

    // convenience

    int next;

    int ttl;

    QString label;

    Q3DnsRR * rr;

    QString readString(bool multipleLabels = true);

    void parseA();

    void parseAaaa();

    void parseMx();

    void parseSrv();

    void parseCname();

    void parsePtr();

    void parseTxt();

    void parseNs();

};

Q3DnsRR::Q3DnsRR( const QString & label )

    : domain( 0 ), t( Q3Dns::None ),

      nxdomain( false ), current( false ),

      expireTime( 0 ), deleteTime( 0 ),

      priority( 0 ), weight( 0 ), port( 0 )

{

    Q3DnsDomain::add( label, this );

}

// not supposed to be deleted except by Q3DnsDomain

Q3DnsRR::~Q3DnsRR()

{

    // nothing is necessary

}

// this one just sticks in a NXDomain

Q3DnsAnswer::Q3DnsAnswer( Q3DnsQuery * query_ )

{

    ok = true;

    answer = 0;

    size = 0;

    query = query_;

    pp = 0;

    rrs = new Q3PtrList<Q3DnsRR>;

    rrs->setAutoDelete( false );

    next = size;

    ttl = 0;

    label.clear();

    rr = 0;

    Q3DnsRR * newrr = new Q3DnsRR( query->l );

    newrr->t = query->t;

    newrr->deleteTime = query->started + 10;

    newrr->expireTime = query->started + 10;

    newrr->nxdomain = true;

    newrr->current = true;

    rrs->append( newrr );

}

Q3DnsAnswer::Q3DnsAnswer( const QByteArray& answer_,

			Q3DnsQuery * query_ )

{

    ok = true;

    answer = (Q_UINT8 *)(answer_.data());

    size = (int)answer_.size();

    query = query_;

    pp = 0;

    rrs = new Q3PtrList<Q3DnsRR>;

    rrs->setAutoDelete( false );

    next = size;

    ttl = 0;

    label.clear();

    rr = 0;

}

Q3DnsAnswer::~Q3DnsAnswer()

{

    if ( !ok && rrs ) {

	Q3PtrListIterator<Q3DnsRR> it( *rrs );

	Q3DnsRR * tmprr;

	while( (tmprr=it.current()) != 0 ) {

	    ++it;

	    tmprr->t = Q3Dns::None; // will be deleted soonish

	}

    }

    delete rrs;

}

QString Q3DnsAnswer::readString(bool multipleLabels)

{

    int p = pp;

    QString r;

    Q_UINT8 b;

    for( ;; ) {

	b = 128;

        // Read one character

        if ( p >= 0 && p < size )

	    b = answer[p];

	switch( b >> 6 ) {

	case 0:

            // b is less than 64

	    p++;

            // Detect end of data

	    if ( b == 0 ) {

		if ( p > pp )

		    pp = p;

                return r.isNull() ? QLatin1String( "." ) : r;

	    }

            // Read a label of size 'b' characters

            if ( !r.isNull() )

		r += QLatin1Char('.');

	    while( b-- > 0 )

                r += QLatin1Char( answer[p++] );

            // Return immediately if we were only supposed to read one

            // label.

            if (!multipleLabels)

                return r;

	    break;

	default:

            // Ignore unrecognized control character, or p was out of

            // range.

	    goto not_ok;

	case 3:

            // Use the next character to determine the relative offset

            // to jump to before continuing the packet parsing.

	    int q = ( (answer[p] & 0x3f) << 8 ) + answer[p+1];

	    if ( q >= pp || q >= p )

		goto not_ok;

	    if ( p >= pp )

		pp = p + 2;

	    p = q;

        }

    }

not_ok:

    ok = false;

    return QString();

}

void Q3DnsAnswer::parseA()

{

    if ( next != pp + 4 ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw %d bytes long IN A for %s",

		next - pp, label.ascii() );

#endif

	return;

    }

    rr = new Q3DnsRR( label );

    rr->t = Q3Dns::A;

    rr->address = QHostAddress( ( answer[pp+0] << 24 ) +

				( answer[pp+1] << 16 ) +

				( answer[pp+2] <<  8 ) +

				( answer[pp+3] ) );

#if defined(Q3DNS_DEBUG)

    qDebug( "Q3Dns: saw %s IN A %s (ttl %d)", label.ascii(),

	    rr->address.toString().ascii(), ttl );

#endif

}

void Q3DnsAnswer::parseAaaa()

{

    if ( next != pp + 16 ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw %d bytes long IN Aaaa for %s",

		next - pp, label.ascii() );

#endif

	return;

    }

    rr = new Q3DnsRR( label );

    rr->t = Q3Dns::Aaaa;

    rr->address = QHostAddress( answer+pp );

#if defined(Q3DNS_DEBUG)

    qDebug( "Q3Dns: saw %s IN Aaaa %s (ttl %d)", label.ascii(),

	    rr->address.toString().ascii(), ttl );

#endif

}

void Q3DnsAnswer::parseMx()

{

    if ( next < pp + 2 ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw %d bytes long IN MX for %s",

		next - pp, label.ascii() );

#endif

	return;

    }

    rr = new Q3DnsRR( label );

    rr->priority = (answer[pp] << 8) + answer[pp+1];

    pp += 2;

    rr->target = readString().lower();

    if ( !ok ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw bad string in MX for %s", label.ascii() );

#endif

	return;

    }

    rr->t = Q3Dns::Mx;

#if defined(Q3DNS_DEBUG)

    qDebug( "Q3Dns: saw %s IN MX %d %s (ttl %d)", label.ascii(),

	    rr->priority, rr->target.ascii(), ttl );

#endif

}

void Q3DnsAnswer::parseSrv()

{

    if ( next < pp + 6 ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw %d bytes long IN SRV for %s",

		next - pp, label.ascii() );

#endif

	return;

    }

    rr = new Q3DnsRR( label );

    rr->priority = (answer[pp] << 8) + answer[pp+1];

    rr->weight = (answer[pp+2] << 8) + answer[pp+3];

    rr->port = (answer[pp+4] << 8) + answer[pp+5];

    pp += 6;

    rr->target = readString().lower();

    if ( !ok ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw bad string in SRV for %s", label.ascii() );

#endif

	return;

    }

    rr->t = Q3Dns::Srv;

#if defined(Q3DNS_DEBUG)

    qDebug( "Q3Dns: saw %s IN SRV %d %d %d %s (ttl %d)", label.ascii(),

	    rr->priority, rr->weight, rr->port, rr->target.ascii(), ttl );

#endif

}

void Q3DnsAnswer::parseCname()

{

    QString target = readString().lower();

    if ( !ok ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw bad cname for for %s", label.ascii() );

#endif

	return;

    }

    rr = new Q3DnsRR( label );

    rr->t = Q3Dns::Cname;

    rr->target = target;

#if defined(Q3DNS_DEBUG)

    qDebug( "Q3Dns: saw %s IN CNAME %s (ttl %d)", label.ascii(),

	    rr->target.ascii(), ttl );

#endif

}

void Q3DnsAnswer::parseNs()

{

    QString target = readString().lower();

    if ( !ok ) {

#if defined(Q3DNS_DEBUG)

	qDebug( "Q3Dns: saw bad cname for for %s", label.ascii() );

#endif

	return;