dns_query.cc | Explore in Territory

// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "net/dns/dns_query.h"

#include <optional>
#include <string_view>
#include <utility>

#include "base/big_endian.h"
#include "base/containers/span.h"
#include "base/containers/span_writer.h"
#include "base/logging.h"
#include "base/memory/ptr_util.h"
#include "base/numerics/byte_conversions.h"
#include "base/numerics/safe_conversions.h"
#include "base/sys_byteorder.h"
#include "net/base/io_buffer.h"
#include "net/dns/dns_names_util.h"
#include "net/dns/opt_record_rdata.h"
#include "net/dns/public/dns_protocol.h"
#include "net/dns/record_rdata.h"

namespace net {

namespace {

const size_t kHeaderSize = …;

// Size of the fixed part of an OPT RR:
// https://tools.ietf.org/html/rfc6891#section-6.1.2
static const size_t kOptRRFixedSize = …;

// https://tools.ietf.org/html/rfc6891#section-6.2.5
// TODO(robpercival): Determine a good value for this programmatically.
const uint16_t kMaxUdpPayloadSize = …;

size_t QuestionSize(size_t qname_size) { … }

// Buffer size of Opt record for |rdata| (does not include Opt record or RData
// added for padding).
size_t OptRecordSize(const OptRecordRdata* rdata) { … }

// Padding size includes Opt header for the padding.  Does not include OptRecord
// header (kOptRRFixedSize) even when added just for padding.
size_t DeterminePaddingSize(size_t unpadded_size,
                            DnsQuery::PaddingStrategy padding_strategy) { … }

std::unique_ptr<OptRecordRdata> AddPaddingIfNecessary(
    const OptRecordRdata* opt_rdata,
    DnsQuery::PaddingStrategy padding_strategy,
    size_t no_opt_buffer_size) { … }

}  // namespace

// DNS query consists of a 12-byte header followed by a question section.
// For details, see RFC 1035 section 4.1.1.  This header template sets RD
// bit, which directs the name server to pursue query recursively, and sets
// the QDCOUNT to 1, meaning the question section has a single entry.
DnsQuery::DnsQuery(uint16_t id,
                   base::span<const uint8_t> qname,
                   uint16_t qtype,
                   const OptRecordRdata* opt_rdata,
                   PaddingStrategy padding_strategy)
    : … { … }

DnsQuery::DnsQuery(scoped_refptr<IOBufferWithSize> buffer)
    : … { … }

DnsQuery::DnsQuery(const DnsQuery& query) { … }

DnsQuery& DnsQuery::operator=(const DnsQuery& query) { … }

DnsQuery::~DnsQuery() = default;

std::unique_ptr<DnsQuery> DnsQuery::CloneWithNewId(uint16_t id) const { … }

bool DnsQuery::Parse(size_t valid_bytes) { … }

uint16_t DnsQuery::id() const { … }

base::span<const uint8_t> DnsQuery::qname() const { … }

uint16_t DnsQuery::qtype() const { … }

std::string_view DnsQuery::question() const { … }

size_t DnsQuery::question_size() const { … }

void DnsQuery::set_flags(uint16_t flags) { … }

DnsQuery::DnsQuery(const DnsQuery& orig, uint16_t id) { … }

void DnsQuery::CopyFrom(const DnsQuery& orig) { … }

bool DnsQuery::ReadHeader(base::SpanReader<const uint8_t>* reader,
                          dns_protocol::Header* header) { … }

bool DnsQuery::ReadName(base::SpanReader<const uint8_t>* reader,
                        std::string* out) { … }

}  // namespace net
chromium/net/dns/dns_query.cc
