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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.
#include <datasrc/zone_finder.h>
#include <datasrc/exceptions.h>
#include <dns/rrclass.h>
#include <dns/rdata.h>
#include <dns/rrset.h>
#include <dns/rrtype.h>
#include <dns/rdataclass.h>
using namespace std;
using namespace isc::dns;
using namespace isc::dns::rdata;
namespace isc {
namespace datasrc {
namespace {
// Identify zone's SOA and return its MINTTL in the form of RRTTL.
RRTTL
getMinTTL(ZoneFinder& finder, ConstRRsetPtr rrset) {
ConstRRsetPtr soa_rrset;
if (rrset->getType() == RRType::SOA()) {
// Shortcut: if we are looking at SOA itself (which should be the
// case in the expected scenario), we can simply use its RDATA.
soa_rrset = rrset;
} else {
soa_rrset =
finder.findAtOrigin(RRType::SOA(), false,
ZoneFinder::FIND_DEFAULT)->rrset;
}
// In a valid zone there is one and only one SOA RR at the origin.
// Otherwise either zone data or the data source implementation is broken.
if (!soa_rrset || soa_rrset->getRdataCount() != 1) {
isc_throw(DataSourceError, "Zone " << rrset->getName().toText(true)
<< "/" << rrset->getClass().toText() << " is broken: "
<< (!soa_rrset ? "no SOA" : "empty SOA"));
}
return (RRTTL(dynamic_cast<const generic::SOA&>(
soa_rrset->getRdataIterator()->getCurrent()).
getMinimum()));
}
// Make a fresh copy of given RRset, just replacing RRTTL with the given one.
RRsetPtr
copyRRset(const AbstractRRset& rrset, const RRTTL& ttl) {
RRsetPtr rrset_copy(new RRset(rrset.getName(), rrset.getClass(),
rrset.getType(), ttl));
for (RdataIteratorPtr rit = rrset.getRdataIterator();
!rit->isLast();
rit->next()) {
rrset_copy->addRdata(rit->getCurrent());
}
ConstRRsetPtr rrsig = rrset.getRRsig();
if (rrsig) {
RRsetPtr rrsig_copy(new RRset(rrset.getName(), rrset.getClass(),
RRType::RRSIG(), ttl));
for (RdataIteratorPtr rit = rrsig->getRdataIterator();
!rit->isLast();
rit->next()) {
rrsig_copy->addRdata(rit->getCurrent());
}
rrset_copy->addRRsig(rrsig_copy);
}
return (rrset_copy);
}
}
ZoneFinderContextPtr
ZoneFinder::findAtOrigin(const dns::RRType& type, bool use_minttl,
FindOptions options)
{
ZoneFinderContextPtr context = find(getOrigin(), type, options);
// If we are requested to use the min TTL and the RRset's RR TTL is larger
// than that, we need to make a copy of the RRset, replacing the TTL,
// and return a newly created context copying other parameters.
if (use_minttl && context->rrset) {
const AbstractRRset& rrset = *context->rrset;
const RRTTL min_ttl = getMinTTL(*this, context->rrset);
if (min_ttl < rrset.getTTL()) {
FindResultFlags flags_copy = RESULT_DEFAULT;
if (context->isWildcard()) {
flags_copy = flags_copy | RESULT_WILDCARD;
}
if (context->isNSECSigned()) {
flags_copy = flags_copy | RESULT_NSEC_SIGNED;
} else if (context->isNSEC3Signed()) {
flags_copy = flags_copy | RESULT_NSEC3_SIGNED;
}
return (ZoneFinderContextPtr(
new GenericContext(*this, options,
ResultContext(context->code,
copyRRset(rrset,
min_ttl),
flags_copy))));
}
}
return (context);
}
isc::dns::ConstRRsetPtr
ZoneFinder::stripRRsigs(isc::dns::ConstRRsetPtr rp,
const FindOptions options) {
if (rp) {
isc::dns::ConstRRsetPtr sig_rrset = rp->getRRsig();
if (sig_rrset &&
((options & ZoneFinder::FIND_DNSSEC) == 0)) {
isc::dns::RRsetPtr result_base
(new isc::dns::RRset(rp->getName(),
rp->getClass(),
rp->getType(),
rp->getTTL()));
for (isc::dns::RdataIteratorPtr i = rp->getRdataIterator();
!i->isLast();
i->next()) {
result_base->addRdata(i->getCurrent());
}
return (result_base);
}
}
return (rp);
}
} // namespace datasrc
} // datasrc isc
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