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// Copyright (C) 2012 Internet Systems Consortium, Inc. ("ISC")
//
// 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 appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND ISC DISCLAIMS ALL WARRANTIES WITH
// REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY
// AND FITNESS. IN NO EVENT SHALL ISC BE LIABLE FOR ANY SPECIAL, DIRECT,
// INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM
// LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE
// OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
// PERFORMANCE OF THIS SOFTWARE.
#ifndef DATASRC_MEMORY_TREENODE_RRSET_H
#define DATASRC_MEMORY_TREENODE_RRSET_H 1
#include <util/buffer.h>
#include <dns/messagerenderer.h>
#include <dns/name.h>
#include <dns/rrclass.h>
#include <dns/rrtype.h>
#include <dns/rrttl.h>
#include <dns/rdata.h>
#include <dns/rrset.h>
#include <datasrc/memory/zone_data.h>
#include <datasrc/memory/rdataset.h>
#include <boost/noncopyable.hpp>
#include <string>
namespace isc {
namespace datasrc {
namespace memory {
/// \brief Special RRset for optimizing memory datasource requirement
///
/// This is a derived class of \c dns::AbstractRRset intended to be used
/// by the in-memory data source finder implementation. It is designed
/// so performance sensitive operations will be lightweight; for example,
/// (in the general case) the construction is just set up references to
/// pre-loaded in-memory objects, not involving any dynamic memory allocation.
/// Its \c toWire() method is also customized so it won't have to use
/// the generic but expensive \c dns::RdataIterator.
///
/// On the other hand, some other performance-insensitive methods could be
/// even less efficient than the generic version. Those include \c getName(),
/// \c toText(), and \c getRdataIterator() methods.
///
/// \note Right now, the authoritative server's query processing still needs
/// to use \c getRdataIterator() and \c getName() for relatively rare case
/// operations. We should revise that part of the authoritative server
/// implementation in the next phase in order to eliminate the bottleneck.
///
/// Since this class is assumed to be instantiated only from the in-memory
/// zone finder, which only returns immutable (const) \c RRset objects,
/// we skip implementing non const virtual methods of this class.
/// Unless the application intentionally breaks the constness or the class
/// is abused outside of the in-memory data source implementation, this
/// should be safe because such methods should never be called.
///
/// Some other const member methods are still incomplete; if they are called
/// it will result in an exception. In the expected usage of this class
/// it should be safe, but we should eventually provide complete
/// implementations of these methods.
///
/// This class can internally maintain dynamically allocated resource.
/// It would cause copying a class object complicated while objects of
/// this class are not expected to be copyable in the usage, so it's
/// explicitly defined non copyable.
///
/// \note This class is exposed in this separate header file so that other
/// part of the in-memory data source implementation and test code
/// can refer to its definition, and only for that purpose. Otherwise this is
/// essentially a private class of the in-memory data source implementation,
/// and an application shouldn't directly refer to this class.
class TreeNodeRRset : boost::noncopyable, public dns::AbstractRRset {
public:
/// \brief Normal case constructor.
///
/// This class object is basically defined with a \c ZoneNode and
/// \c RdataSet. The former determines the owner name of the RRset,
/// and the latter provides the rest of the RRset parameters.
/// Since the RR class is maintained outside of the \c ZoneData,
/// it must be explicitly given as a constructor parameter.
///
/// The \c RdataSet may or may not be associated with RRSIGs. It's
/// fixed at the load time, but depending on the query context they
/// may or may not be requested (and supposed to be visible to the
/// caller). Since \c rdataset cannot be modified at the time of
/// construction, a separate parameter (\c dnssec_ok) controls this
/// policy. Any associated RRSIGs are visible if and only if \c dnssec_ok
/// is true. If the RRset is not associated with RRSIGs, the value
/// does not have any effect.
///
/// In some rare cases \c rdataset may only consist of RRSIGs (when
/// the zone contains an RRSIG that doesn't have covered RRsets).
/// This class works for such cases, too.
///
/// \throw none
///
/// \param rrclass The RR class of the RRset. This must be consistent
/// with the corresponding zone class.
/// \param node The \c ZoneNode for the \c RRset. Must not be NULL.
/// \param rdataset The \c RdataSet for the \c RRset. Must not be NULL.
/// \param dnssec_ok Whether the RRSIGs for the RRset (if associated)
/// should be visible to the caller.
TreeNodeRRset(const dns::RRClass& rrclass, const ZoneNode* node,
const RdataSet* rdataset, bool dnssec_ok) :
node_(node), rdataset_(rdataset),
rrsig_count_(rdataset_->getSigRdataCount()), rrclass_(rrclass),
dnssec_ok_(dnssec_ok), name_(NULL), realname_(NULL),
ttl_data_(rdataset->getTTLData()), ttl_(NULL)
{}
/// \brief Constructor with a specific TTL.
///
/// This constructor is mostly the same as the normal version, but takes
/// an extra parameter, \c ttl_data. It's expected to point to a memory
/// region at least for 32 bits, and the corresponding 32-bit data will
/// be used as wire-format TTL value of the RRset, instead of the TTL
/// associated with \c rdataset.
///
/// It's the caller's responsibility to guarantee the memory region is
/// valid and intact throughout the lifetime of the RRset.
///
/// \throw None
TreeNodeRRset(const dns::RRClass& rrclass, const ZoneNode* node,
const RdataSet* rdataset, bool dnssec_ok,
const void* ttl_data) :
node_(node), rdataset_(rdataset),
rrsig_count_(rdataset_->getSigRdataCount()), rrclass_(rrclass),
dnssec_ok_(dnssec_ok), name_(NULL), realname_(NULL),
ttl_data_(ttl_data), ttl_(NULL)
{}
/// \brief Constructor for wildcard-expanded owner name.
///
/// This constructor is mostly the same as the normal version, but takes
/// an extra parameter, \c realname. It effectively overrides the owner
/// name of the RRset; wherever the owner name is used (e.g., in the
/// \c toWire() method), the specified name will be used instead of
/// the name associated with \c node.
///
/// The expected usage is \c node has a wildcard name (such as
/// *.example.com), but this constructor does not enforce the assumption.
///
/// \throw std::bad_alloc Memory allocation fails
TreeNodeRRset(const dns::Name& realname, const dns::RRClass& rrclass,
const ZoneNode* node, const RdataSet* rdataset,
bool dnssec_ok) :
node_(node), rdataset_(rdataset),
rrsig_count_(rdataset_->getSigRdataCount()), rrclass_(rrclass),
dnssec_ok_(dnssec_ok), name_(NULL), realname_(new dns::Name(realname)),
ttl_data_(rdataset->getTTLData()), ttl_(NULL)
{}
virtual ~TreeNodeRRset() {
delete realname_;
delete ttl_;
delete name_;
}
virtual unsigned int getRdataCount() const {
return (rdataset_->getRdataCount());
}
virtual const dns::Name& getName() const;
virtual const dns::RRClass& getClass() const {
return (rrclass_);
}
virtual const dns::RRType& getType() const {
return (rdataset_->type);
}
/// \brief Specialized version of \c getTTL() for \c TreeNodeRRset.
virtual const dns::RRTTL& getTTL() const;
/// \brief Specialized version of \c setTTL() for \c TreeNodeRRset.
///
/// It throws \c isc::Unexpected unconditionally.
virtual void setTTL(const dns::RRTTL& ttl);
virtual std::string toText() const;
virtual unsigned int toWire(dns::AbstractMessageRenderer& renderer) const;
/// \brief Specialized version of \c toWire(buffer) for \c TreeNodeRRset.
///
/// It throws \c isc::Unexpected unconditionally.
virtual unsigned int toWire(util::OutputBuffer& buffer) const;
/// \brief Specialized version of \c addRdata() for \c TreeNodeRRset.
///
/// It throws \c isc::Unexpected unconditionally.
virtual void addRdata(dns::rdata::ConstRdataPtr rdata);
/// \brief Specialized version of \c addRdata() for \c TreeNodeRRset.
///
/// It throws \c isc::Unexpected unconditionally.
virtual void addRdata(const dns::rdata::Rdata& rdata);
virtual dns::RdataIteratorPtr getRdataIterator() const;
/// \brief Specialized version of \c getRRsig() for \c TreeNodeRRset.
virtual dns::RRsetPtr getRRsig() const;
virtual unsigned int getRRsigDataCount() const {
return (dnssec_ok_ ? rrsig_count_ : 0);
}
///
/// \name Specialized version of RRsig related methods for
/// \c TreeNodeRRset.
///
/// These throw \c isc::Unexpected unconditionally.
////
//@{
virtual void addRRsig(const dns::rdata::ConstRdataPtr& rdata);
virtual void addRRsig(const dns::rdata::RdataPtr& rdata);
virtual void addRRsig(const dns::AbstractRRset& sigs);
virtual void addRRsig(const dns::ConstRRsetPtr& sigs);
virtual void addRRsig(const dns::RRsetPtr& sigs);
virtual void removeRRsig();
//@}
/// \brief Specialized version of \c isSameKind() for \c TreeNodeRRset.
///
/// As a kind of optimization, this implementation exploits the assumption
/// of how \c TreeNodeRRset objects are created: They must be always
/// created inside the in-memory data source finder implementation,
/// and they are constructed with the \c realname parameter if and only
/// if the corresponding query name is subject to wildcard substitution.
///
/// So, if the given RRset is of \c TreeNodeRRset, and one and only one of
/// of them has \c realname, they are considered to have different names.
///
/// Also, this implementation does not compare RR classes explicitly;
/// if two \c TreeNodeRRset objects belong to different RR classes,
/// they should belong to different zone trees (according to the assumption
/// of how the zone data are built), and therefore they cannot be at
/// same zone node. So it's sufficient to compare the (address of the)
/// node; if they are different they cannot be of the same kind.
virtual bool isSameKind(const dns::AbstractRRset& abs_other) const;
private:
dns::RdataIteratorPtr getSigRdataIterator() const;
// Common backend for getRdataIterator() and getSigRdataIterator()
dns::RdataIteratorPtr getRdataIteratorInternal(bool is_rrsig,
size_t count) const;
// Return \c LabelSequence for the owner name regardless of how this
/// class is constructed (with or without 'realname')
dns::LabelSequence getOwnerLabels(
uint8_t labels_buf[dns::LabelSequence::MAX_SERIALIZED_LENGTH]) const
{
if (realname_ != NULL) {
return (dns::LabelSequence(*realname_));
}
return (node_->getAbsoluteLabels(labels_buf));
}
const ZoneNode* node_;
const RdataSet* rdataset_;
const size_t rrsig_count_;
const dns::RRClass rrclass_;
const bool dnssec_ok_;
mutable dns::Name* name_;
const dns::Name* const realname_;
const void* const ttl_data_;
mutable dns::RRTTL* ttl_;
};
typedef boost::shared_ptr<TreeNodeRRset> TreeNodeRRsetPtr;
} // namespace memory
} // namespace datasrc
} // namespace isc
#endif // DATASRC_MEMORY_TREENODE_RRSET_H
// Local Variables:
// mode: c++
// End:
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