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Diffstat (limited to 'src/lib/dns/message.cc')
| -rw-r--r-- | src/lib/dns/message.cc | 1176 |
1 files changed, 1176 insertions, 0 deletions
diff --git a/src/lib/dns/message.cc b/src/lib/dns/message.cc new file mode 100644 index 0000000..fe05a3e --- /dev/null +++ b/src/lib/dns/message.cc @@ -0,0 +1,1176 @@ +// Copyright (C) 2009-2023 Internet Systems Consortium, Inc. ("ISC") +// +// This Source Code Form is subject to the terms of the Mozilla Public +// License, v. 2.0. If a copy of the MPL was not distributed with this +// file, You can obtain one at http://mozilla.org/MPL/2.0/. + +#include <config.h> + +#include <stdint.h> + +#include <algorithm> +#include <cassert> +#include <string> +#include <sstream> +#include <vector> + +#include <boost/foreach.hpp> +#include <boost/lexical_cast.hpp> +#include <boost/shared_ptr.hpp> + +#include <exceptions/exceptions.h> + +#include <util/buffer.h> + +#include <dns/edns.h> +#include <dns/exceptions.h> +#include <dns/message.h> +#include <dns/messagerenderer.h> +#include <dns/name.h> +#include <dns/opcode.h> +#include <dns/rcode.h> +#include <dns/question.h> +#include <dns/rdataclass.h> +#include <dns/rrclass.h> +#include <dns/rrtype.h> +#include <dns/rrttl.h> +#include <dns/rrset.h> +#include <dns/tsig.h> + +using namespace std; +using boost::lexical_cast; +using namespace isc::dns::rdata; +using namespace isc::util; + +namespace isc { +namespace dns { + +namespace { +// protocol constants +const size_t HEADERLEN = 12; + +const unsigned int OPCODE_MASK = 0x7800; +const unsigned int OPCODE_SHIFT = 11; +const unsigned int RCODE_MASK = 0x000f; + +// This diagram shows the wire-format representation of the 2nd 16 bits of +// the DNS header section, which contain all defined flag bits. +// +// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +// |QR| Opcode |AA|TC|RD|RA| |AD|CD| RCODE | +// +--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+ +// 1 0 0 0| 0 1 1 1| 1 0 1 1| 0 0 0 0| +// 0x8 0x7 0xb 0x0 +// +// This mask covers all the flag bits, and those bits only. +// Note: we reject a "flag" the is not covered by this mask in some of the +// public methods. This means our current definition is not fully extendable; +// applications cannot introduce a new flag bit temporarily without modifying +// the source code. +const unsigned int HEADERFLAG_MASK = 0x87b0; + +// This is a set of flag bits that should be preserved when building a reply +// from a request. +// Note: we assume the specific definition of HEADERFLAG_xx. We may change +// the definition in future, in which case we need to adjust this definition, +// too (see also the description about the Message::HeaderFlag type). +const uint16_t MESSAGE_REPLYPRESERVE = (Message::HEADERFLAG_RD | + Message::HEADERFLAG_CD); + +const char* const sectiontext[] = { + "QUESTION", + "ANSWER", + "AUTHORITY", + "ADDITIONAL" +}; +} + +class MessageImpl { +public: + MessageImpl(Message::Mode mode); + // Open issues: should we rather have a header in wire-format + // for efficiency? + Message::Mode mode_; + qid_t qid_; + + // We want to use NULL for [op,r]code_ to mean the code being not + // correctly parsed or set. We store the real code object in + // xxcode_placeholder_ and have xxcode_ refer to it when the object + // is valid. + const Rcode* rcode_; + Rcode rcode_placeholder_; + const Opcode* opcode_; + Opcode opcode_placeholder_; + + uint16_t flags_; // wire-format representation of header flags. + + bool header_parsed_; + static const unsigned int NUM_SECTIONS = 4; // TODO: revisit this design + int counts_[NUM_SECTIONS]; // TODO: revisit this definition + vector<QuestionPtr> questions_; + vector<RRsetPtr> rrsets_[NUM_SECTIONS]; + ConstEDNSPtr edns_; + ConstTSIGRecordPtr tsig_rr_; + + // RRsetsSorter* sorter_; : TODO + + void init(); + void setOpcode(const Opcode& opcode); + void setRcode(const Rcode& rcode); + int parseQuestion(InputBuffer& buffer); + int parseSection(const Message::Section section, InputBuffer& buffer, + Message::ParseOptions options); + void addRR(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, ConstRdataPtr rdata, + Message::ParseOptions options); + // There are also times where an RR needs to be added that + // represents an empty RRset. There is no Rdata in that case + void addRR(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, Message::ParseOptions options); + void addEDNS(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, const Rdata& rdata); + void addTSIG(Message::Section section, unsigned int count, + const InputBuffer& buffer, size_t start_position, + const Name& name, const RRClass& rrclass, + const RRTTL& ttl, const Rdata& rdata); + void toWire(AbstractMessageRenderer& renderer, TSIGContext* tsig_ctx); +}; + +/// @brief Pointer to the @ref MessageImpl object. +typedef boost::shared_ptr<MessageImpl> MessageImplPtr; + +MessageImpl::MessageImpl(Message::Mode mode) : + mode_(mode), + rcode_placeholder_(Rcode(0)), // for placeholders the value doesn't matter + opcode_placeholder_(Opcode(0)) { + init(); +} + +void +MessageImpl::init() { + flags_ = 0; + qid_ = 0; + rcode_ = NULL; + opcode_ = NULL; + edns_ = EDNSPtr(); + tsig_rr_ = ConstTSIGRecordPtr(); + + for (int i = 0; i < NUM_SECTIONS; ++i) { + counts_[i] = 0; + } + + header_parsed_ = false; + questions_.clear(); + rrsets_[Message::SECTION_ANSWER].clear(); + rrsets_[Message::SECTION_AUTHORITY].clear(); + rrsets_[Message::SECTION_ADDITIONAL].clear(); +} + +void +MessageImpl::setOpcode(const Opcode& opcode) { + opcode_placeholder_ = opcode; + opcode_ = &opcode_placeholder_; +} + +void +MessageImpl::setRcode(const Rcode& rcode) { + rcode_placeholder_ = rcode; + rcode_ = &rcode_placeholder_; +} + +namespace { +// This helper class is used by MessageImpl::toWire() to render a set of +// RRsets of a specific section of message to a given MessageRenderer. +// +// A RenderSection object is expected to be used with a QuestionIterator or +// SectionIterator. Its operator() is called for each RRset as the iterator +// iterates over the corresponding section, and it renders the RRset to +// the given MessageRenderer, while counting the number of RRs (note: not +// RRsets) successfully rendered. If the MessageRenderer reports the need +// for truncation (via its isTruncated() method), the RenderSection object +// stops rendering further RRsets. In addition, unless partial_ok (given on +// construction) is true, it removes any RRs that are partially rendered +// from the MessageRenderer. +// +// On the completion of rendering the entire section, the owner of the +// RenderSection object can get the number of rendered RRs via the +// getTotalCount() method. +template <typename T> +struct RenderSection { + RenderSection(AbstractMessageRenderer& renderer, const bool partial_ok) : + counter_(0), renderer_(renderer), partial_ok_(partial_ok), + truncated_(false) { + } + + void operator()(const T& entry) { + // If it's already truncated, ignore the rest of the section. + if (truncated_) { + return; + } + const size_t pos0 = renderer_.getLength(); + counter_ += entry->toWire(renderer_); + if (renderer_.isTruncated()) { + truncated_ = true; + if (!partial_ok_) { + // roll back to the end of the previous RRset. + renderer_.trim(renderer_.getLength() - pos0); + } + } + } + + unsigned int getTotalCount() { + return (counter_); + } + + unsigned int counter_; + + AbstractMessageRenderer& renderer_; + + const bool partial_ok_; + + bool truncated_; +}; +} + +void +MessageImpl::toWire(AbstractMessageRenderer& renderer, TSIGContext* tsig_ctx) { + if (mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "Message rendering attempted in non render mode"); + } + if (rcode_ == NULL) { + isc_throw(InvalidMessageOperation, + "Message rendering attempted without Rcode set"); + } + if (opcode_ == NULL) { + isc_throw(InvalidMessageOperation, + "Message rendering attempted without Opcode set"); + } + + // Reserve the space for TSIG (if needed) so that we can handle truncation + // case correctly later when that happens. orig_xxx variables remember + // some configured parameters of renderer in case they are needed in + // truncation processing below. + const size_t tsig_len = (tsig_ctx != NULL) ? tsig_ctx->getTSIGLength() : 0; + const size_t orig_msg_len_limit = renderer.getLengthLimit(); + const AbstractMessageRenderer::CompressMode orig_compress_mode = + renderer.getCompressMode(); + + // We are going to skip soon, so we need to clear the renderer + // But we'll leave the length limit and the compress mode intact + // (or shortened in case of TSIG) + renderer.clear(); + renderer.setCompressMode(orig_compress_mode); + + if (tsig_len > 0) { + if (tsig_len > orig_msg_len_limit) { + isc_throw(InvalidParameter, "Failed to render DNS message: " + "too small limit for a TSIG (" << + orig_msg_len_limit << ")"); + } + renderer.setLengthLimit(orig_msg_len_limit - tsig_len); + } else { + renderer.setLengthLimit(orig_msg_len_limit); + } + + // reserve room for the header + if (renderer.getLengthLimit() < HEADERLEN) { + isc_throw(InvalidParameter, "Failed to render DNS message: " + "too small limit for a Header"); + } + renderer.skip(HEADERLEN); + + uint16_t qdcount = + for_each(questions_.begin(), questions_.end(), + RenderSection<QuestionPtr>(renderer, false)).getTotalCount(); + + // TODO: sort RRsets in each section based on configuration policy. + uint16_t ancount = 0; + if (!renderer.isTruncated()) { + ancount = + for_each(rrsets_[Message::SECTION_ANSWER].begin(), + rrsets_[Message::SECTION_ANSWER].end(), + RenderSection<RRsetPtr>(renderer, true)).getTotalCount(); + } + uint16_t nscount = 0; + if (!renderer.isTruncated()) { + nscount = + for_each(rrsets_[Message::SECTION_AUTHORITY].begin(), + rrsets_[Message::SECTION_AUTHORITY].end(), + RenderSection<RRsetPtr>(renderer, true)).getTotalCount(); + } + uint16_t arcount = 0; + if (renderer.isTruncated()) { + flags_ |= Message::HEADERFLAG_TC; + } else { + arcount = + for_each(rrsets_[Message::SECTION_ADDITIONAL].begin(), + rrsets_[Message::SECTION_ADDITIONAL].end(), + RenderSection<RRsetPtr>(renderer, false)).getTotalCount(); + } + + // Add EDNS OPT RR if necessary. Basically, we add it only when EDNS + // has been explicitly set. However, if the RCODE would require it and + // no EDNS has been set we generate a temporary local EDNS and use it. + if (!renderer.isTruncated()) { + ConstEDNSPtr local_edns = edns_; + if (!local_edns && rcode_->getExtendedCode() != 0) { + local_edns = ConstEDNSPtr(new EDNS()); + } + if (local_edns) { + arcount += local_edns->toWire(renderer, rcode_->getExtendedCode()); + } + } + + // If we're adding a TSIG to a truncated message, clear all RRsets + // from the message except for the question before adding the TSIG. + // If even (some of) the question doesn't fit, don't include it. + if (tsig_ctx != NULL && renderer.isTruncated()) { + renderer.clear(); + renderer.setLengthLimit(orig_msg_len_limit - tsig_len); + renderer.setCompressMode(orig_compress_mode); + renderer.skip(HEADERLEN); + qdcount = for_each(questions_.begin(), questions_.end(), + RenderSection<QuestionPtr>(renderer, + false)).getTotalCount(); + ancount = 0; + nscount = 0; + arcount = 0; + } + + // Adjust the counter buffer. + // XXX: these may not be equal to the number of corresponding entries + // in rrsets_[] or questions_ if truncation occurred or an EDNS OPT RR + // was inserted. This is not good, and we should revisit the entire + // design. + counts_[Message::SECTION_QUESTION] = qdcount; + counts_[Message::SECTION_ANSWER] = ancount; + counts_[Message::SECTION_AUTHORITY] = nscount; + counts_[Message::SECTION_ADDITIONAL] = arcount; + + // fill in the header + size_t header_pos = 0; + renderer.writeUint16At(qid_, header_pos); + header_pos += sizeof(uint16_t); + + uint16_t codes_and_flags = + (opcode_->getCode() << OPCODE_SHIFT) & OPCODE_MASK; + codes_and_flags |= (rcode_->getCode() & RCODE_MASK); + codes_and_flags |= (flags_ & HEADERFLAG_MASK); + renderer.writeUint16At(codes_and_flags, header_pos); + header_pos += sizeof(uint16_t); + // TODO: should avoid repeated pattern + renderer.writeUint16At(qdcount, header_pos); + header_pos += sizeof(uint16_t); + renderer.writeUint16At(ancount, header_pos); + header_pos += sizeof(uint16_t); + renderer.writeUint16At(nscount, header_pos); + header_pos += sizeof(uint16_t); + renderer.writeUint16At(arcount, header_pos); + + // Add TSIG, if necessary, at the end of the message. + if (tsig_ctx != NULL) { + // Release the reserved space in the renderer. + renderer.setLengthLimit(orig_msg_len_limit); + + const int tsig_count = + tsig_ctx->sign(qid_, renderer.getData(), + renderer.getLength())->toWire(renderer); + if (tsig_count != 1) { + isc_throw(Unexpected, "Failed to render a TSIG RR"); + } + + // update the ARCOUNT for the TSIG RR. Note that for a sane DNS + // message arcount should never overflow to 0. + renderer.writeUint16At(++arcount, header_pos); + } +} + +Message::Message(Mode mode) : + impl_(new MessageImpl(mode)) { +} + +bool +Message::getHeaderFlag(const HeaderFlag flag) const { + if (flag == 0 || (flag & ~HEADERFLAG_MASK) != 0) { + isc_throw(InvalidParameter, + "Message::getHeaderFlag:: Invalid flag is specified: " << + "0x" << std::hex << flag); + } + return ((impl_->flags_ & flag) != 0); +} + +void +Message::setHeaderFlag(const HeaderFlag flag, const bool on) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "setHeaderFlag performed in non-render mode"); + } + if (flag == 0 || (flag & ~HEADERFLAG_MASK) != 0) { + isc_throw(InvalidParameter, + "Message::getHeaderFlag:: Invalid flag is specified: " << + "0x" << std::hex << static_cast<int>(flag)); + } + if (on) { + impl_->flags_ |= flag; + } else { + impl_->flags_ &= ~flag; + } +} + +qid_t +Message::getQid() const { + return (impl_->qid_); +} + +void +Message::setQid(qid_t qid) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "setQid performed in non-render mode"); + } + impl_->qid_ = qid; +} + +const Rcode& +Message::getRcode() const { + if (impl_->rcode_ == NULL) { + isc_throw(InvalidMessageOperation, "getRcode attempted before set"); + } + return (*impl_->rcode_); +} + +void +Message::setRcode(const Rcode& rcode) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "setRcode performed in non-render mode"); + } + impl_->setRcode(rcode); +} + +const Opcode& +Message::getOpcode() const { + if (impl_->opcode_ == NULL) { + isc_throw(InvalidMessageOperation, "getOpcode attempted before set"); + } + return (*impl_->opcode_); +} + +void +Message::setOpcode(const Opcode& opcode) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "setOpcode performed in non-render mode"); + } + impl_->setOpcode(opcode); +} + +ConstEDNSPtr +Message::getEDNS() const { + return (impl_->edns_); +} + +void +Message::setEDNS(ConstEDNSPtr edns) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "setEDNS performed in non-render mode"); + } + impl_->edns_ = edns; +} + +const TSIGRecord* +Message::getTSIGRecord() const { + if (impl_->mode_ != Message::PARSE) { + isc_throw(InvalidMessageOperation, + "getTSIGRecord performed in non-parse mode"); + } + + return (impl_->tsig_rr_.get()); +} + +unsigned int +Message::getRRCount(const Section section) const { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + return (impl_->counts_[section]); +} + +void +Message::addRRset(const Section section, RRsetPtr rrset) { + if (!rrset) { + isc_throw(InvalidParameter, + "NULL RRset is given to Message::addRRset"); + } + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "addRRset performed in non-render mode"); + } + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + + impl_->rrsets_[section].push_back(rrset); + impl_->counts_[section] += rrset->getRdataCount(); + impl_->counts_[section] += rrset->getRRsigDataCount(); +} + +bool +Message::hasRRset(const Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype) const { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + + BOOST_FOREACH(ConstRRsetPtr r, impl_->rrsets_[section]) { + if (r->getClass() == rrclass && + r->getType() == rrtype && + r->getName() == name) { + return (true); + } + } + + return (false); +} + +bool +Message::hasRRset(const Section section, const RRsetPtr& rrset) const { + return (hasRRset(section, rrset->getName(), + rrset->getClass(), rrset->getType())); +} + +bool +Message::removeRRset(const Section section, RRsetIterator& iterator) { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + + bool removed = false; + for (vector<RRsetPtr>::iterator i = impl_->rrsets_[section].begin(); + i != impl_->rrsets_[section].end(); ++i) { + if (((*i)->getName() == (*iterator)->getName()) && + ((*i)->getClass() == (*iterator)->getClass()) && + ((*i)->getType() == (*iterator)->getType())) { + + // Found the matching RRset so remove it & ignore rest + impl_->counts_[section] -= (*iterator)->getRdataCount(); + impl_->counts_[section] -= (*iterator)->getRRsigDataCount(); + impl_->rrsets_[section].erase(i); + removed = true; + break; + } + } + + return (removed); +} + +void +Message::clearSection(const Section section) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "clearSection performed in non-render mode"); + } + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + if (section == Message::SECTION_QUESTION) { + impl_->questions_.clear(); + } else { + impl_->rrsets_[section].clear(); + } + impl_->counts_[section] = 0; +} + +void +Message::addQuestion(const QuestionPtr question) { + if (impl_->mode_ != Message::RENDER) { + isc_throw(InvalidMessageOperation, + "addQuestion performed in non-render mode"); + } + + impl_->questions_.push_back(question); + ++impl_->counts_[SECTION_QUESTION]; +} + +void +Message::addQuestion(const Question& question) { + addQuestion(QuestionPtr(new Question(question))); +} + +void +Message::toWire(AbstractMessageRenderer& renderer, TSIGContext* tsig_ctx) { + impl_->toWire(renderer, tsig_ctx); +} + +void +Message::parseHeader(InputBuffer& buffer) { + if (impl_->mode_ != Message::PARSE) { + isc_throw(InvalidMessageOperation, + "Message parse attempted in non parse mode"); + } + + if (impl_->header_parsed_) { + return; + } + + if ((buffer.getLength() - buffer.getPosition()) < HEADERLEN) { + isc_throw(MessageTooShort, "Malformed DNS message (short length): " + << buffer.getLength() - buffer.getPosition()); + } + + impl_->qid_ = buffer.readUint16(); + const uint16_t codes_and_flags = buffer.readUint16(); + impl_->setOpcode(Opcode((codes_and_flags & OPCODE_MASK) >> OPCODE_SHIFT)); + impl_->setRcode(Rcode(codes_and_flags & RCODE_MASK)); + impl_->flags_ = (codes_and_flags & HEADERFLAG_MASK); + impl_->counts_[SECTION_QUESTION] = buffer.readUint16(); + impl_->counts_[SECTION_ANSWER] = buffer.readUint16(); + impl_->counts_[SECTION_AUTHORITY] = buffer.readUint16(); + impl_->counts_[SECTION_ADDITIONAL] = buffer.readUint16(); + + impl_->header_parsed_ = true; +} + +void +Message::fromWire(InputBuffer& buffer, ParseOptions options) { + if (impl_->mode_ != Message::PARSE) { + isc_throw(InvalidMessageOperation, + "Message parse attempted in non parse mode"); + } + + // Clear any old parsed data + clear(Message::PARSE); + + buffer.setPosition(0); + parseHeader(buffer); + + impl_->counts_[SECTION_QUESTION] = impl_->parseQuestion(buffer); + impl_->counts_[SECTION_ANSWER] = + impl_->parseSection(SECTION_ANSWER, buffer, options); + impl_->counts_[SECTION_AUTHORITY] = + impl_->parseSection(SECTION_AUTHORITY, buffer, options); + impl_->counts_[SECTION_ADDITIONAL] = + impl_->parseSection(SECTION_ADDITIONAL, buffer, options); +} + +int +MessageImpl::parseQuestion(InputBuffer& buffer) { + unsigned int added = 0; + + for (unsigned int count = 0; + count < counts_[Message::SECTION_QUESTION]; + ++count) { + const Name name(buffer); + + if ((buffer.getLength() - buffer.getPosition()) < + 2 * sizeof(uint16_t)) { + isc_throw(DNSMessageFORMERR, "Question section too short: " << + (buffer.getLength() - buffer.getPosition()) << " bytes"); + } + const RRType rrtype(buffer.readUint16()); + const RRClass rrclass(buffer.readUint16()); + + // XXX: need a duplicate check. We might also want to have an + // optimized algorithm that requires the question section contain + // exactly one RR. + + questions_.push_back(QuestionPtr(new Question(name, rrclass, rrtype))); + ++added; + } + + return (added); +} + +namespace { +struct MatchRR { + MatchRR(const Name& name, const RRType& rrtype, const RRClass& rrclass) : + name_(name), rrtype_(rrtype), rrclass_(rrclass) { + } + + bool operator()(const RRsetPtr& rrset) const { + return (rrset->getType() == rrtype_ && + rrset->getClass() == rrclass_ && + rrset->getName() == name_); + } + + const Name& name_; + + const RRType& rrtype_; + + const RRClass& rrclass_; +}; +} + +// Note about design decision: +// we need some type specific processing here, including EDNS and TSIG. +// how much we should generalize/hardcode the special logic is subject +// to discussion. In terms of modularity it would be ideal to introduce +// an abstract class (say "MessageAttribute") and let other such +// concrete notions as EDNS or TSIG inherit from it. Then we would +// just do: +// message->addAttribute(rrtype, rrclass, buffer); +// to create and attach type-specific concrete object to the message. +// +// A major downside of this approach is, as usual, complexity due to +// indirection and performance penalty. Also, it may not be so easy +// to separate the processing logic because in many cases we'll need +// parse context for which the message class is responsible (e.g. +// to check the EDNS OPT RR only appears in the additional section, +// and appears only once). +// +// Another point to consider is that we may not need so many special +// types other than EDNS and TSIG (and when and if we implement it, +// SIG(0)); newer optional attributes of the message would more likely +// be standardized as new flags or options of EDNS. If that's the case, +// introducing an abstract class with all the overhead and complexity +// may not make much sense. +// +// Conclusion: don't over-generalize type-specific logic for now. +// introduce separate concrete classes, and move context-independent +// logic to that class; processing logic dependent on parse context +// is hardcoded here. +int +MessageImpl::parseSection(const Message::Section section, + InputBuffer& buffer, Message::ParseOptions options) { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + + unsigned int added = 0; + + for (unsigned int count = 0; count < counts_[section]; ++count) { + // We need to remember the start position for TSIG processing + const size_t start_position = buffer.getPosition(); + + const Name name(buffer); + + // buffer must store at least RR TYPE, RR CLASS, TTL, and RDLEN. + if ((buffer.getLength() - buffer.getPosition()) < + 3 * sizeof(uint16_t) + sizeof(uint32_t)) { + isc_throw(DNSMessageFORMERR, sectiontext[section] << + " section too short: " << + (buffer.getLength() - buffer.getPosition()) << " bytes"); + } + + const RRType rrtype(buffer.readUint16()); + const RRClass rrclass(buffer.readUint16()); + const RRTTL ttl(buffer.readUint32()); + const size_t rdlen = buffer.readUint16(); + + // If class is ANY or NONE, rdlength may be zero, to signal + // an empty RRset. + // (the class check must be done to differentiate from RRTypes + // that can have zero length rdata + if ((rrclass == RRClass::ANY() || rrclass == RRClass::NONE()) && + rdlen == 0) { + addRR(section, name, rrclass, rrtype, ttl, options); + ++added; + continue; + } + ConstRdataPtr rdata = createRdata(rrtype, rrclass, buffer, rdlen); + + if (rrtype == RRType::OPT()) { + addEDNS(section, name, rrclass, rrtype, ttl, *rdata); + } else if (rrtype == RRType::TSIG()) { + addTSIG(section, count, buffer, start_position, name, rrclass, ttl, + *rdata); + } else { + addRR(section, name, rrclass, rrtype, ttl, rdata, options); + ++added; + } + } + + return (added); +} + +void +MessageImpl::addRR(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, ConstRdataPtr rdata, + Message::ParseOptions options) { + if ((options & Message::PRESERVE_ORDER) == 0) { + vector<RRsetPtr>::iterator it = + find_if(rrsets_[section].begin(), rrsets_[section].end(), + MatchRR(name, rrtype, rrclass)); + if (it != rrsets_[section].end()) { + (*it)->setTTL(min((*it)->getTTL(), ttl)); + (*it)->addRdata(rdata); + return; + } + } + RRsetPtr rrset(new RRset(name, rrclass, rrtype, ttl)); + rrset->addRdata(rdata); + rrsets_[section].push_back(rrset); +} + +void +MessageImpl::addRR(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, Message::ParseOptions options) { + if ((options & Message::PRESERVE_ORDER) == 0) { + vector<RRsetPtr>::iterator it = + find_if(rrsets_[section].begin(), rrsets_[section].end(), + MatchRR(name, rrtype, rrclass)); + if (it != rrsets_[section].end()) { + (*it)->setTTL(min((*it)->getTTL(), ttl)); + return; + } + } + RRsetPtr rrset(new RRset(name, rrclass, rrtype, ttl)); + rrsets_[section].push_back(rrset); +} + +void +MessageImpl::addEDNS(Message::Section section, const Name& name, + const RRClass& rrclass, const RRType& rrtype, + const RRTTL& ttl, const Rdata& rdata) { + if (section != Message::SECTION_ADDITIONAL) { + isc_throw(DNSMessageFORMERR, + "EDNS OPT RR found in an invalid section"); + } + if (edns_) { + isc_throw(DNSMessageFORMERR, "multiple EDNS OPT RR found"); + } + + uint8_t extended_rcode; + edns_ = ConstEDNSPtr(createEDNSFromRR(name, rrclass, rrtype, ttl, rdata, + extended_rcode)); + setRcode(Rcode(rcode_->getCode(), extended_rcode)); +} + +void +MessageImpl::addTSIG(Message::Section section, unsigned int count, + const InputBuffer& buffer, size_t start_position, + const Name& name, const RRClass& rrclass, + const RRTTL& ttl, const Rdata& rdata) { + if (section != Message::SECTION_ADDITIONAL) { + isc_throw(DNSMessageFORMERR, + "TSIG RR found in an invalid section"); + } + if (count != counts_[section] - 1) { + isc_throw(DNSMessageFORMERR, "TSIG RR is not the last record"); + } + // This check will never fail as the multiple TSIG RR case is + // caught before by the not the last record check... + if (tsig_rr_) { + isc_throw(DNSMessageFORMERR, "multiple TSIG RRs found"); + } + tsig_rr_ = ConstTSIGRecordPtr(new TSIGRecord(name, rrclass, + ttl, rdata, + buffer.getPosition() - + start_position)); +} + +namespace { +template <typename T> +struct SectionFormatter { + SectionFormatter(const Message::Section section, string& output) : + section_(section), output_(output) { + } + + void operator()(const T& entry) { + if (section_ == Message::SECTION_QUESTION) { + output_ += ";"; + output_ += entry->toText(); + output_ += "\n"; + } else { + output_ += entry->toText(); + } + } + + const Message::Section section_; + + string& output_; +}; +} + +string +Message::toText() const { + if (impl_->rcode_ == NULL) { + isc_throw(InvalidMessageOperation, + "Message::toText() attempted without Rcode set"); + } + if (impl_->opcode_ == NULL) { + isc_throw(InvalidMessageOperation, + "Message::toText() attempted without Opcode set"); + } + + string s; + + s += ";; ->>HEADER<<- opcode: " + impl_->opcode_->toText(); + // for simplicity we don't consider extended rcode (unlike BIND9) + s += ", status: " + impl_->rcode_->toText(); + s += ", id: " + boost::lexical_cast<string>(impl_->qid_); + s += "\n;; flags:"; + if (getHeaderFlag(HEADERFLAG_QR)) { + s += " qr"; + } + if (getHeaderFlag(HEADERFLAG_AA)) { + s += " aa"; + } + if (getHeaderFlag(HEADERFLAG_TC)) { + s += " tc"; + } + if (getHeaderFlag(HEADERFLAG_RD)) { + s += " rd"; + } + if (getHeaderFlag(HEADERFLAG_RA)) { + s += " ra"; + } + if (getHeaderFlag(HEADERFLAG_AD)) { + s += " ad"; + } + if (getHeaderFlag(HEADERFLAG_CD)) { + s += " cd"; + } + + // for simplicity, don't consider the update case for now + s += "; QUERY: " + // note: not "QUESTION" to be compatible with BIND 9 dig + lexical_cast<string>(impl_->counts_[SECTION_QUESTION]); + s += ", ANSWER: " + + lexical_cast<string>(impl_->counts_[SECTION_ANSWER]); + s += ", AUTHORITY: " + + lexical_cast<string>(impl_->counts_[SECTION_AUTHORITY]); + + unsigned int arcount = impl_->counts_[SECTION_ADDITIONAL]; + if (impl_->edns_ != NULL) { + ++arcount; + } + if (impl_->tsig_rr_ != NULL) { + ++arcount; + } + s += ", ADDITIONAL: " + lexical_cast<string>(arcount) + "\n"; + + if (impl_->edns_ != NULL) { + s += "\n;; OPT PSEUDOSECTION:\n"; + s += impl_->edns_->toText(); + } + + if (!impl_->questions_.empty()) { + s += "\n;; " + + string(sectiontext[SECTION_QUESTION]) + " SECTION:\n"; + for_each(impl_->questions_.begin(), impl_->questions_.end(), + SectionFormatter<QuestionPtr>(SECTION_QUESTION, s)); + } + if (!impl_->rrsets_[SECTION_ANSWER].empty()) { + s += "\n;; " + + string(sectiontext[SECTION_ANSWER]) + " SECTION:\n"; + for_each(impl_->rrsets_[SECTION_ANSWER].begin(), + impl_->rrsets_[SECTION_ANSWER].end(), + SectionFormatter<RRsetPtr>(SECTION_ANSWER, s)); + } + if (!impl_->rrsets_[SECTION_AUTHORITY].empty()) { + s += "\n;; " + + string(sectiontext[SECTION_AUTHORITY]) + " SECTION:\n"; + for_each(impl_->rrsets_[SECTION_AUTHORITY].begin(), + impl_->rrsets_[SECTION_AUTHORITY].end(), + SectionFormatter<RRsetPtr>(SECTION_AUTHORITY, s)); + } + if (!impl_->rrsets_[SECTION_ADDITIONAL].empty()) { + s += "\n;; " + + string(sectiontext[SECTION_ADDITIONAL]) + + " SECTION:\n"; + for_each(impl_->rrsets_[SECTION_ADDITIONAL].begin(), + impl_->rrsets_[SECTION_ADDITIONAL].end(), + SectionFormatter<RRsetPtr>(SECTION_ADDITIONAL, s)); + } + + if (impl_->tsig_rr_ != NULL) { + s += "\n;; TSIG PSEUDOSECTION:\n"; + s += impl_->tsig_rr_->toText(); + } + + return (s); +} + +void +Message::clear(Mode mode) { + impl_->init(); + impl_->mode_ = mode; +} + +void +Message::appendSection(const Section section, const Message& source) { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + + if (section == SECTION_QUESTION) { + for (QuestionIterator qi = source.beginQuestion(); + qi != source.endQuestion(); + ++qi) { + addQuestion(*qi); + } + } else { + for (RRsetIterator rrsi = source.beginSection(section); + rrsi != source.endSection(section); + ++rrsi) { + addRRset(section, *rrsi); + } + } +} + +void +Message::makeResponse() { + if (impl_->mode_ != Message::PARSE) { + isc_throw(InvalidMessageOperation, + "makeResponse() is performed in non-parse mode"); + } + + impl_->mode_ = Message::RENDER; + + impl_->edns_ = EDNSPtr(); + impl_->flags_ &= MESSAGE_REPLYPRESERVE; + setHeaderFlag(HEADERFLAG_QR, true); + + impl_->rrsets_[SECTION_ANSWER].clear(); + impl_->counts_[SECTION_ANSWER] = 0; + impl_->rrsets_[SECTION_AUTHORITY].clear(); + impl_->counts_[SECTION_AUTHORITY] = 0; + impl_->rrsets_[SECTION_ADDITIONAL].clear(); + impl_->counts_[SECTION_ADDITIONAL] = 0; +} + +/// +/// Template version of Section Iterator +/// +template <typename T> +struct SectionIteratorImpl { + SectionIteratorImpl(const typename vector<T>::const_iterator& it) : + it_(it) { + } + + typename vector<T>::const_iterator it_; +}; + +template <typename T> +SectionIterator<T>::SectionIterator(const SectionIteratorImpl<T>& impl) { + impl_ = new SectionIteratorImpl<T>(impl.it_); +} + +template <typename T> +SectionIterator<T>::~SectionIterator() { + delete impl_; +} + +template <typename T> +SectionIterator<T>::SectionIterator(const SectionIterator<T>& source) : + impl_(new SectionIteratorImpl<T>(source.impl_->it_)) { +} + +template <typename T> +void +SectionIterator<T>::operator=(const SectionIterator<T>& source) { + if (impl_ == source.impl_) { + return; + } + SectionIteratorImpl<T>* newimpl = + new SectionIteratorImpl<T>(source.impl_->it_); + delete impl_; + impl_ = newimpl; +} + +template <typename T> +SectionIterator<T>& +SectionIterator<T>::operator++() { + ++(impl_->it_); + return (*this); +} + +template <typename T> +SectionIterator<T> +SectionIterator<T>::operator++(int) { + SectionIterator<T> tmp(*this); + ++(*this); + return (tmp); +} + +template <typename T> +const T& +SectionIterator<T>::operator*() const { + return (*(impl_->it_)); +} + +template <typename T> +const T* +SectionIterator<T>::operator->() const { + return (&(operator*())); +} + +template <typename T> +bool +SectionIterator<T>::operator==(const SectionIterator<T>& other) const { + return (impl_->it_ == other.impl_->it_); +} + +template <typename T> +bool +SectionIterator<T>::operator!=(const SectionIterator<T>& other) const { + return (impl_->it_ != other.impl_->it_); +} + +/// +/// We need to explicitly instantiate these template classes because these +/// are public classes but defined in this implementation file. +/// +template class SectionIterator<QuestionPtr>; +template class SectionIterator<RRsetPtr>; + +namespace { +typedef SectionIteratorImpl<QuestionPtr> QuestionIteratorImpl; +typedef SectionIteratorImpl<RRsetPtr> RRsetIteratorImpl; +} + +/// +/// Question iterator +/// +const QuestionIterator +Message::beginQuestion() const { + return (QuestionIterator(QuestionIteratorImpl(impl_->questions_.begin()))); +} + +const QuestionIterator +Message::endQuestion() const { + return (QuestionIterator(QuestionIteratorImpl(impl_->questions_.end()))); +} + +/// +/// RRsets iterators +/// +const SectionIterator<RRsetPtr> +Message::beginSection(const Section section) const { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + if (section == SECTION_QUESTION) { + isc_throw(InvalidMessageSection, + "RRset iterator is requested for question"); + } + + return (RRsetIterator(RRsetIteratorImpl(impl_->rrsets_[section].begin()))); +} + +const SectionIterator<RRsetPtr> +Message::endSection(const Section section) const { + if (static_cast<int>(section) >= MessageImpl::NUM_SECTIONS) { + isc_throw(OutOfRange, "Invalid message section: " << static_cast<int>(section)); + } + if (section == SECTION_QUESTION) { + isc_throw(InvalidMessageSection, + "RRset iterator is requested for question"); + } + + return (RRsetIterator(RRsetIteratorImpl(impl_->rrsets_[section].end()))); +} + +ostream& +operator<<(ostream& os, const Message& message) { + return (os << message.toText()); +} +} // end of namespace dns +} // end of namespace isc |