zeroconfservicebrowserdnssd.cpp

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#include "zeroconfservicebrowserdnssd.h"
#include "loggingcategories.h"

#include <QHostAddress>
#include <QtEndian>
#include <QHostInfo>

#include <netdb.h>

ZeroConfServiceBrowserDnssd::ZeroConfServiceBrowserDnssd(const QString &serviceType, QObject *parent) :
    ZeroConfServiceBrowser(QString(), parent)
{
    if (serviceType.isEmpty()) {
        qCWarning(dcPlatformZeroConf) << "The Bonjour plugin does not support browsing all services. You must specify a serviceType.";
        return;
    }

    DNSServiceErrorType err = DNSServiceBrowse(&m_browser, 0, 0, serviceType.toUtf8(), 0, (DNSServiceBrowseReply) ZeroConfServiceBrowserDnssd::browseCallback, this);
    if (err != kDNSServiceErr_NoError) {
        qCWarning(dcPlatformZeroConf) << "Failed to create service browser:" << err;
        return;
    }

    int sockFd = DNSServiceRefSockFD(m_browser);
    if (sockFd == -1) {
        DNSServiceRefDeallocate(m_browser);
        return;
    }

    m_socketNotifier = new QSocketNotifier(sockFd, QSocketNotifier::Read, this);
    connect(m_socketNotifier, &QSocketNotifier::activated, this, [this]{
        DNSServiceErrorType err = DNSServiceProcessResult(m_browser);
        if (err != kDNSServiceErr_NoError) {
            DNSServiceRefDeallocate(m_browser);
            m_socketNotifier->deleteLater();
        }
    });

    qCDebug(dcPlatformZeroConf) << "Service browser created.";
}

ZeroConfServiceBrowserDnssd::~ZeroConfServiceBrowserDnssd()
{
}

QList<ZeroConfServiceEntry> ZeroConfServiceBrowserDnssd::serviceEntries() const
{
    return m_serviceEntries.values();
}

void DNSSD_API ZeroConfServiceBrowserDnssd::browseCallback(DNSServiceRef sdRef, DNSServiceFlags flags, uint32_t interfaceIndex, DNSServiceErrorType errorCode, const char *serviceName, const char *regtype, const char *replyDomain, void *context)
{
    Q_UNUSED(sdRef)
    Q_UNUSED(errorCode)

    ZeroConfServiceBrowserDnssd *self = static_cast<ZeroConfServiceBrowserDnssd*>(context);

    if (flags & kDNSServiceFlagsAdd) {

        qCDebug(dcPlatformZeroConf) << "Service appeared:" << QString("%1.%2").arg(serviceName).arg(regtype) << flags << interfaceIndex;

        Context *resolverContext = new Context();
        resolverContext->self = self;
        resolverContext->name = QString::fromUtf8(serviceName);
        resolverContext->serviceType = QString::fromUtf8(regtype);
        resolverContext->serviceType.remove(QRegExp(".$"));
        resolverContext->domain = QString::fromUtf8(replyDomain);

        DNSServiceErrorType err = DNSServiceResolve(&resolverContext->ref, 0, interfaceIndex, serviceName, regtype, replyDomain, (DNSServiceResolveReply) ZeroConfServiceBrowserDnssd::resolveCallback, resolverContext);
        if (err != kDNSServiceErr_NoError) {
            qCWarning(dcPlatformZeroConf) << "Failed to create service resolver:" << err;
            delete resolverContext;
            return;
        }

        int sockFd = DNSServiceRefSockFD(resolverContext->ref);
        if (sockFd == -1) {
            DNSServiceRefDeallocate(resolverContext->ref);
            delete resolverContext;
            return;
        }

        resolverContext->socketNotifier = new QSocketNotifier(sockFd, QSocketNotifier::Read, self);
        connect(resolverContext->socketNotifier, &QSocketNotifier::activated, self, [resolverContext]{
            DNSServiceErrorType err = DNSServiceProcessResult(resolverContext->ref);
            if (err != kDNSServiceErr_NoError) {
                DNSServiceRefDeallocate(resolverContext->ref);
                resolverContext->socketNotifier->deleteLater();
                delete resolverContext;
            }
        });

    } else if (flags == 0x00) {
        QString serviceType = regtype;
        serviceType.remove(QRegExp(".$"));

        QString id = QString("%1.%2@%3").arg(serviceName).arg(serviceType).arg(interfaceIndex);

        qCDebug(dcPlatformZeroConf) << "Service disappeared:" << id;

        if (self->m_serviceEntries.contains(id)) {
            qCDebug(dcPlatformZeroConf()) << "Entry removed:" << id;
            ZeroConfServiceEntry entry = self->m_serviceEntries.take(id);
            emit self->serviceEntryRemoved(entry);
        }
    }
}

void ZeroConfServiceBrowserDnssd::resolveCallback(DNSServiceRef sdRef, DNSServiceFlags flags, uint32_t interfaceIndex, DNSServiceErrorType errorCode, const char *fullname, const char *hosttarget, uint16_t port, uint16_t txtLen, const unsigned char *txtRecord, void *context)
{
    Q_UNUSED(sdRef)
    Q_UNUSED(flags)
    Q_UNUSED(interfaceIndex)
    Q_UNUSED(fullname)
//    qCDebug(dcPlatformZeroConf) << "Resolve callback" << flags << interfaceIndex << errorCode << fullname << hosttarget << port << txtLen << txtRecord << context;

    Context *resolverContext = static_cast<Context*>(context);
    ZeroConfServiceBrowserDnssd *self = resolverContext->self;
    DNSServiceRefDeallocate(resolverContext->ref);
    delete resolverContext->socketNotifier;

    if (errorCode != kDNSServiceErr_NoError) {
        qCWarning(dcPlatformZeroConf) << "Failed to resolve service" << fullname << "Error code:" << errorCode;
        delete resolverContext;
        return;
    }

    Context *addrContext = new Context();
    addrContext->self = self;
    addrContext->name = resolverContext->name;
    addrContext->serviceType = resolverContext->serviceType;
    addrContext->domain = resolverContext->domain;
    addrContext->hostName = QString::fromUtf8(hosttarget);
    addrContext->port = qFromBigEndian<quint16>(port);
    addrContext->interfaceIndex = interfaceIndex;
    QStringList txt;
    qint16 recLen;
    while (txtLen > 0) {
        recLen = txtRecord[0];
        txtRecord++;
        QByteArray t((const char *)txtRecord, recLen);
        QList<QByteArray> pair = t.split('=');
        if (pair.size() == 2) {
            txt.append(pair.at(0) + "=" + pair.at(1));
        } else {
            txt.append(pair.at(0));
        }
        txtLen-= recLen + 1;
        txtRecord+= recLen;
    }
    addrContext->txt = txt;
    delete resolverContext;

    qCDebug(dcPlatformZeroConf()) << "Resolving host for" << fullname << hosttarget;

    // From here on we resolve the services host address.
    // The avahi compat lib does not implement DNSServiceGetAddrInfo. We can use other
    // means to resolve the address, however, neither QHostInfo nor gethostbyname allows us
    // to restrict resolving to a certain interface and that messes up stuff if we discover
    // the same service on different interfaces. We don't know how to deduplicate them any more.
    // To behave better on systems where DNSServiceGetAddrInfo is available, let's use that.


#ifdef AVAHI_COMPAT
    // Resolve using QHostInfo when using the AVAHI libdns compat lib.
    int jobId = QHostInfo::lookupHost(hosttarget, self, SLOT(lookupFinished(QHostInfo)));
    self->m_pendingLookups.insert(jobId, addrContext);

#else

    // Resolve using DNSServiceGetAddrInfo when building against a proper libdns_sd.

    errorCode = DNSServiceGetAddrInfo(&addrContext->ref, kDNSServiceFlagsForceMulticast, interfaceIndex, kDNSServiceProtocol_IPv4, hosttarget, (DNSServiceGetAddrInfoReply)addressCallback, addrContext);
    if (errorCode != kDNSServiceErr_NoError) {
        qCWarning(dcPlatformZeroConf) << "Failed to get address info";
        delete addrContext;
    }
    int sockfd = DNSServiceRefSockFD(addrContext->ref);
    if (sockfd == -1) {
        DNSServiceRefDeallocate(addrContext->ref);
        delete addrContext;
    }

    addrContext->socketNotifier = new QSocketNotifier(sockfd, QSocketNotifier::Read, self);
    connect(addrContext->socketNotifier, &QSocketNotifier::activated, self, [addrContext](){
        DNSServiceErrorType err = DNSServiceProcessResult(addrContext->ref);
        if (err != kDNSServiceErr_NoError) {
            DNSServiceRefDeallocate(addrContext->ref);
            addrContext->socketNotifier->deleteLater();
            delete addrContext;
        }
    });
#endif
}


#ifdef AVAHI_COMPAT
void ZeroConfServiceBrowserDnssd::lookupFinished(const QHostInfo &info)
{
    if (!m_pendingLookups.contains(info.lookupId())) {
        qCWarning(dcPlatformZeroConf()) << "Lookup finished but we don't have a request for it";
        return;
    }
    Context *addrContext = m_pendingLookups.take(info.lookupId());

    if (info.error() != QHostInfo::NoError) {
        qCWarning(dcPlatformZeroConf()) << "Error resolving host address for" << addrContext->serviceType << addrContext->hostName << info.errorString();
        return;
    }
    QString id = QString("%1.%2@%3").arg(addrContext->name).arg(addrContext->serviceType).arg(addrContext->interfaceIndex);

    qCDebug(dcPlatformZeroConf()) << "Host resolved" << id;
    foreach (const QHostAddress &addr, info.addresses()) {
        ZeroConfServiceEntry entry = ZeroConfServiceEntry(addrContext->name, addrContext->serviceType, addr, addrContext->domain, addrContext->hostName, addrContext->port, addr.protocol(), addrContext->txt, false, false, false, false, false);

        if (!m_serviceEntries.contains(id)) {
            qCDebug(dcPlatformZeroConf()) << "Entry added" << id << "(" + entry.hostAddress().toString() + ")";
            m_serviceEntries.insert(id, entry);
            emit serviceEntryAdded(entry);
        } else {
            qCDebug(dcPlatformZeroConf()) << "Discarding duplicate entry:" << id << "(" + entry.hostAddress().toString() + ")";
        }
    }
    delete addrContext;
}

#else


void ZeroConfServiceBrowserDnssd::addressCallback(DNSServiceRef sdRef, DNSServiceFlags flags, uint32_t interfaceIndex, DNSServiceErrorType errorCode, const char *hostname, const sockaddr *address, uint32_t ttl, void *context)
{
    Q_UNUSED(sdRef)
    Q_UNUSED(flags)
    Q_UNUSED(hostname)
    Q_UNUSED(ttl)

    Context *addressContext = static_cast<Context*>(context);
    ZeroConfServiceBrowserDnssd *self = addressContext->self;
    DNSServiceRefDeallocate(addressContext->ref);
    delete addressContext->socketNotifier;

    if (errorCode != kDNSServiceErr_NoError) {
        qCWarning(dcPlatformZeroConf) << "Failed to resolve address" << errorCode;
        delete addressContext;
        return;
    }

    QHostAddress addr(address);

    QString id = QString("%1.%2@%3").arg(addressContext->name).arg(addressContext->serviceType).arg(interfaceIndex);
    qCDebug(dcPlatformZeroConf()) << "Host resolved" << id;

    ZeroConfServiceEntry entry = ZeroConfServiceEntry(addressContext->name, addressContext->serviceType, addr, addressContext->domain, addressContext->hostName, addressContext->port, QAbstractSocket::IPv4Protocol, addressContext->txt, false, false, false, false, false);

    if (!self->m_serviceEntries.contains(id)) {
        qCDebug(dcPlatformZeroConf()) << "Entry added" << id << "(" + entry.hostAddress().toString() + ")";
        self->m_serviceEntries.insert(id, entry);
        emit self->serviceEntryAdded(entry);
    } else {
        qCDebug(dcPlatformZeroConf()) << "Discarding duplicate entry:" << id << "(" + entry.hostAddress().toString() + ")";
    }

    delete addressContext;
}

#endif