q3dns.cpp

奇趣公司比较新的qt/emd版本

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#include "qplatformdefs.h"
#include "qbytearray.h"
#ifdef Q_OS_WIN32
# 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>

//#define Q3DNS_DEBUG

static Q_UINT16 id; // ### 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() );
    ::id = originOfTime->time().msec() * 60 + originOfTime->time().second();
    q3dns_cleanup_time.add( &originOfTime );
    return 0;
}


static Q3PtrList<QHostAddress> * ns = 0;
static Q3StrList * domains = 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;
    }

    // parse, but ignore