q3dns.cpp

奇趣公司比较新的qt/emd版本

#if defined(Q3DNS_DEBUG)
    qDebug( "Q3Dns: saw %s IN NS %s (ttl %d)", label.ascii(),
	    target.ascii(), ttl );
#endif
}


void Q3DnsAnswer::parsePtr()
{
    QString target = readString().lower();
    if ( !ok ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "Q3Dns: saw bad PTR for for %s", label.ascii() );
#endif
	return;
    }

    rr = new Q3DnsRR( label );
    rr->t = Q3Dns::Ptr;
    rr->target = target;
#if defined(Q3DNS_DEBUG)
    qDebug( "Q3Dns: saw %s IN PTR %s (ttl %d)", label.ascii(),
	    rr->target.ascii(), ttl );
#endif
}


void Q3DnsAnswer::parseTxt()
{
    QString text = readString(false);
    if ( !ok ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "Q3Dns: saw bad TXT for for %s", label.ascii() );
#endif
	return;
    }

    rr = new Q3DnsRR( label );
    rr->t = Q3Dns::Txt;
    rr->text = text;
#if defined(Q3DNS_DEBUG)
    qDebug( "Q3Dns: saw %s IN TXT \"%s\" (ttl %d)", label.ascii(),
	    rr->text.ascii(), ttl );
#endif
}


void Q3DnsAnswer::parse()
{
    // okay, do the work...
    if ( (answer[2] & 0x78) != 0 ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: answer to wrong query type (%d)", answer[1] );
#endif
	ok = false;
	return;
    }

    // AA
    bool aa = (answer[2] & 4) != 0;

    // TC
    if ( (answer[2] & 2) != 0 ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: truncated answer; pressing on" );
#endif
    }

    // RD
    bool rd = (answer[2] & 1) != 0;

    // we don't test RA
    // we don't test the MBZ fields

    if ( (answer[3] & 0x0f) == 3 ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: saw NXDomain for %s", query->l.ascii() );
#endif
	// NXDomain.  cache that for one minute.
	rr = new Q3DnsRR( query->l );
	rr->t = query->t;
	rr->deleteTime = query->started + 60;
	rr->expireTime = query->started + 60;
	rr->nxdomain = true;
	rr->current = true;
	rrs->append( rr );
	return;
    }

    if ( (answer[3] & 0x0f) != 0 ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: error code %d", answer[3] & 0x0f );
#endif
	ok = false;
	return;
    }

    int qdcount = ( answer[4] << 8 ) + answer[5];
    int ancount = ( answer[6] << 8 ) + answer[7];
    int nscount = ( answer[8] << 8 ) + answer[9];
    int adcount = (answer[10] << 8 ) +answer[11];

    pp = 12;

    // read query
    while( qdcount > 0 && pp < size ) {
	// should I compare the string against query->l?
	(void)readString();
	if ( !ok )
	    return;
	pp += 4;
	qdcount--;
    }

    // answers and stuff
    int rrno = 0;
    // if we parse the answer completely, but there are no answers,
    // ignore the entire thing.
    int answers = 0;
    while( ( rrno < ancount ||
	     ( ok && answers >0 && rrno < ancount + nscount + adcount ) ) &&
	   pp < size ) {
	label = readString().lower();
	if ( !ok )
	    return;
	int rdlength = 0;
	if ( pp + 10 <= size )
	    rdlength = ( answer[pp+8] << 8 ) + answer[pp+9];
	if ( pp + 10 + rdlength > size ) {
#if defined(Q3DNS_DEBUG)
	    qDebug( "DNS Manager: ran out of stuff to parse (%d+%d>%d (%d)",
		    pp, rdlength, size, rrno < ancount );
#endif
	    // if we're still in the AN section, we should go back and
	    // at least down the TTLs.  probably best to invalidate
	    // the results.
	    // the rrs list is good for this
	    ok = ( rrno < ancount );
	    return;
	}
	uint type, clas;
	type = ( answer[pp+0] << 8 ) + answer[pp+1];
	clas = ( answer[pp+2] << 8 ) + answer[pp+3];
	ttl = ( answer[pp+4] << 24 ) + ( answer[pp+5] << 16 ) +
	      ( answer[pp+6] <<  8 ) + answer[pp+7];
	pp = pp + 10;
	if ( clas != 1 ) {
#if defined(Q3DNS_DEBUG)
	    qDebug( "DNS Manager: class %d (not internet) for %s",
		    clas, label.isNull() ? "." : label.ascii() );
#endif
	} else {
            next = pp + rdlength;
	    rr = 0;
	    switch( type ) {
	    case 1:
		parseA();
		break;
	    case 28:
		parseAaaa();
		break;
	    case 15:
		parseMx();
		break;
	    case 33:
		parseSrv();
		break;
	    case 5:
		parseCname();
		break;
	    case 12:
		parsePtr();
		break;
	    case 16:
		parseTxt();
		break;
	    case 2:
		parseNs();
		break;
	    default:
		// something we don't know
#if defined(Q3DNS_DEBUG)
		qDebug( "DNS Manager: type %d for %s", type,
			label.isNull() ? "." : label.ascii() );
#endif
		break;
	    }
	    if ( rr ) {
		rr->deleteTime = 0;
		if ( ttl > 0 )
		    rr->expireTime = query->started + ttl;
		else
		    rr->expireTime = query->started + 20;
		if ( rrno < ancount ) {
		    answers++;
		    rr->deleteTime = rr->expireTime;
		}
		rr->current = true;
		rrs->append( rr );
	    }
        }
	if ( !ok )
	    return;
	pp = next;
	next = size;
	rrno++;
    }
    if ( answers == 0 ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: answer contained no answers" );
#endif
	ok = ( aa && rd );
    }

    // now go through the list and mark all the As that are referenced
    // by something we care about.  we want to cache such As.
    rrs->first();
    Q3Dict<void> used( 17 );
    used.setAutoDelete( false );
    while( (rr=rrs->current()) != 0 ) {
	rrs->next();
	if ( rr->target.length() && rr->deleteTime > 0 && rr->current )
	    used.insert( rr->target, (void*)42 );
	if ( ( rr->t == Q3Dns::A || rr->t == Q3Dns::Aaaa ) &&
	     used.find( rr->domain->name() ) != 0 )
	    rr->deleteTime = rr->expireTime;
    }

    // next, for each RR, delete any older RRs that are equal to it
    rrs->first();
    while( (rr=rrs->current()) != 0 ) {
	rrs->next();
	if ( rr && rr->domain && rr->domain->rrs ) {
	    Q3PtrList<Q3DnsRR> * drrs = rr->domain->rrs;
	    drrs->first();
	    Q3DnsRR * older;
	    while( (older=drrs->current()) != 0 ) {
		if ( older != rr &&
		     older->t == rr->t &&
		     older->nxdomain == rr->nxdomain &&
		     older->address == rr->address &&
		     older->target == rr->target &&
		     older->priority == rr->priority &&
		     older->weight == rr->weight &&
		     older->port == rr->port &&
		     older->text == rr->text ) {
		    // well, it's equal, but it's not the same. so we kill it,
		    // but use its expiry time.
#if defined(Q3DNS_DEBUG)
		    qDebug( "killing off old %d for %s, expire was %d",
                            older->t, older->domain->name().latin1(),
                            rr->expireTime );
#endif
		    older->t = Q3Dns::None;
		    rr->expireTime = QMAX( older->expireTime, rr->expireTime );
		    rr->deleteTime = QMAX( older->deleteTime, rr->deleteTime );
		    older->deleteTime = 0;
#if defined(Q3DNS_DEBUG)
		    qDebug( "    adjusted expire is %d", rr->expireTime );
#endif
		}
		drrs->next();
	    }
	}
    }

#if defined(Q3DNS_DEBUG)
    //qDebug( "DNS Manager: ()" );
#endif
}


class Q3DnsUgleHack: public Q3Dns {
public:
    void ugle( bool emitAnyway=false );
};


void Q3DnsAnswer::notify()
{
    if ( !rrs || !ok || !query || !query->dns )
	return;

    Q3PtrDict<void> notified;
    notified.setAutoDelete( false );

    Q3PtrDictIterator<void> it( *query->dns );
    Q3Dns * dns;
    it.toFirst();
    while( (dns=(Q3Dns*)(it.current())) != 0 ) {
	++it;
	if ( notified.find( (void*)dns ) == 0 ) {
	    notified.insert( (void*)dns, (void*)42 );
	    if ( rrs->count() == 0 ) {
#if defined(Q3DNS_DEBUG)
		qDebug( "DNS Manager: found no answers!" );
#endif
		dns->d->noNames = true;
		((Q3DnsUgleHack*)dns)->ugle( true );
	    } else {
		QStringList n = dns->qualifiedNames();
		if ( query && n.contains(query->l) )
		    ((Q3DnsUgleHack*)dns)->ugle();
#if defined(Q3DNS_DEBUG)
		else
		    qDebug( "DNS Manager: DNS thing %s not notified for %s",
			    dns->label().ascii(), query->l.ascii() );
#endif
	    }
	}
    }
}


//
//
// Q3DnsManager
//
//


class Q3DnsManager: public Q3DnsSocket {
private:
public: // just to silence the moronic g++.
    Q3DnsManager();
    ~Q3DnsManager();
public:
    static Q3DnsManager * manager();

    Q3DnsDomain * domain( const QString & );

    void transmitQuery( Q3DnsQuery * );
    void transmitQuery( int );

    // reimplementation of the slots
    void cleanCache();
    void retransmit();
    void answer();

public:
    Q3PtrVector<Q3DnsQuery> queries;
    Q3Dict<Q3DnsDomain> cache;
    Q3SocketDevice * ipv4Socket;
#if !defined (QT_NO_IPV6)
    Q3SocketDevice * ipv6Socket;
#endif
};



static Q3DnsManager * globalManager = 0;

static void cleanupDns()
{
    delete globalManager;
    globalManager = 0;
}

Q3DnsManager * Q3DnsManager::manager()
{
    if ( !globalManager ) {
        qAddPostRoutine(cleanupDns);
	new Q3DnsManager();
    }
    return globalManager;
}


void Q3DnsUgleHack::ugle( bool emitAnyway)
{
    if ( emitAnyway || !isWorking() ) {
#if defined(Q3DNS_DEBUG)
	qDebug( "DNS Manager: status change for %s (type %d)",
		label().ascii(), recordType() );
#endif
	emit resultsReady();
    }
}


Q3DnsManager::Q3DnsManager()
    : Q3DnsSocket( qApp, "Internal DNS manager" ),
      queries( Q3PtrVector<Q3DnsQuery>( 0 ) ),
      cache( Q3Dict<Q3DnsDomain>( 83, false ) ),
      ipv4Socket( new Q3SocketDevice( Q3SocketDevice::Datagram, Q3SocketDevice::IPv4, 0 ) )
#if !defined (QT_NO_IPV6)
      , ipv6Socket( new Q3SocketDevice( Q3SocketDevice::Datagram, Q3SocketDevice::IPv6, 0 ) )
#endif
{
    cache.setAutoDelete( true );
    globalManager = this;

    QTimer * sweepTimer = new QTimer( this );
    sweepTimer->start( 1000 * 60 * 3 );
    connect( sweepTimer, SIGNAL(timeout()),
	     this, SLOT(cleanCache()) );

    QSocketNotifier * rn4 = new QSocketNotifier( ipv4Socket->socket(),
						 QSocketNotifier::Read,
						 this, "dns IPv4 socket watcher" );
    ipv4Socket->setAddressReusable( false );
    ipv4Socket->setBlocking( false );
    connect( rn4, SIGNAL(activated(int)), SLOT(answer()) );

#if !defined (QT_NO_IPV6)
    // Don't connect the IPv6 socket notifier if the host does not
    // support IPv6.
    if ( ipv6Socket->socket() != -1 ) {
	QSocketNotifier * rn6 = new QSocketNotifier( ipv6Socket->socket(),
						     QSocketNotifier::Read,
						     this, "dns IPv6 socket watcher" );

	ipv6support = true;
	ipv6Socket->setAddressReusable( false );
	ipv6Socket->setBlocking( false );
	connect( rn6, SIGNAL(activated(int)), SLOT(answer()) );
    }
#endif

    if ( !ns )
	Q3Dns::doResInit();

    // O(n*n) stuff here.  but for 3 and 6, O(n*n) with a low k should
    // be perfect.  the point is to eliminate any duplicates that
    // might be hidden in the lists.
    Q3PtrList<QHostAddress> * ns = new Q3PtrList<QHostAddress>;

    ::ns->first();
    QHostAddress * h;
    while( (h=::ns->current()) != 0 ) {
	ns->first();
	while( ns->current() != 0 && !(*ns->current() == *h) )
	    ns->next();
	if ( !ns->current() ) {
	    ns->append( new QHostAddress(*h) );
#if defined(Q3DNS_DEBUG)
	    qDebug( "using name server %s", h->toString().latin1() );
	} else {
	    qDebug( "skipping address %s", h->toString().latin1() );
#endif
	}
	::ns->next();
    }

    delete ::ns;
    ::ns = ns;
    ::ns->setAutoDelete( true );

    Q3StrList * domains = new Q3StrList( true );

    ::domains->first();
    const char * s;
    while( (s=::domains->current()) != 0 ) {
	domains->first();
	while( domains->current() != 0 && qstrcmp( domains->current(), s ) )
	    domains->next();
	if ( !domains->current() ) {
	    domains->append( s );
#if defined(Q3DNS_DEBUG)
	    qDebug( "searching domain %s", s );
	} else {
	    qDebug( "skipping domain %s", s );
#endif
	}
	::domains->next();
    }

    delete ::domains;
    ::domains = domains;
    ::domains->setAutoDelete( true );
}


Q3DnsManager::~Q3DnsManager()
{
    if ( globalManager )
	globalManager = 0;
    queries.setAutoDelete( true );
    cache.setAutoDelete( true );
    delete ipv4Socket;
#if !defined (QT_NO_IPV6)
    delete ipv6Socket;
#endif
}

static Q_UINT32 lastSweep = 0;

void Q3DnsManager::cleanCache()
{
    bool again = false;
    Q3DictIterator<Q3DnsDomain> it( cache );
    Q3DnsDomain * d;
    Q_UINT32 thisSweep = now();
#if defined(Q3DNS_DEBUG)
    qDebug( "Q3DnsManager::cleanCache(: Called, time is %u, last was %u",
	   thisSweep, lastSweep );
#endif

    while( (d=it.current()) != 0 ) {
	++it;
	d->sweep( thisSweep ); // after this, d may be empty
	if ( !again )
	    again = !d->isEmpty();
    }
    if ( !again )
	delete this;
    lastSweep = thisSweep;
}


void Q3DnsManager::retransmit()
{
    const QObject * o = sender();
    if ( o == 0 || globalManager == 0 || this != globalManager )
	return;
    uint q = 0;
    while( q < queries.size() && queries[q] != o )
	q++;
    if ( q < queries.size() )
	transmitQuery( q );
}


void Q3DnsManager::answer()
{