net/dns/record_rdata.cc

   1 // Copyright (c) 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "net/dns/record_rdata.h"
   6
   7 #include "base/big_endian.h"
   8 #include "net/base/ip_address_number.h"
   9 #include "net/dns/dns_protocol.h"
  10 #include "net/dns/dns_response.h"
  11
  12 namespace net {
  13
  14 static const size_t kSrvRecordMinimumSize = 6;
  15
  16 RecordRdata::RecordRdata() {
  17 }
  18
  19 SrvRecordRdata::SrvRecordRdata() : priority_(0), weight_(0), port_(0) {
  20 }
  21
  22 SrvRecordRdata::~SrvRecordRdata() {}
  23
  24 // static
  25 scoped_ptr<SrvRecordRdata> SrvRecordRdata::Create(
  26     const base::StringPiece& data,
  27     const DnsRecordParser& parser) {
  28   if (data.size() < kSrvRecordMinimumSize) return scoped_ptr<SrvRecordRdata>();
  29
  30   scoped_ptr<SrvRecordRdata> rdata(new SrvRecordRdata);
  31
  32   base::BigEndianReader reader(data.data(), data.size());
  33   // 2 bytes for priority, 2 bytes for weight, 2 bytes for port.
  34   reader.ReadU16(&rdata->priority_);
  35   reader.ReadU16(&rdata->weight_);
  36   reader.ReadU16(&rdata->port_);
  37
  38   if (!parser.ReadName(data.substr(kSrvRecordMinimumSize).begin(),
  39                        &rdata->target_))
  40     return scoped_ptr<SrvRecordRdata>();
  41
  42   return rdata.Pass();
  43 }
  44
  45 uint16 SrvRecordRdata::Type() const {
  46   return SrvRecordRdata::kType;
  47 }
  48
  49 bool SrvRecordRdata::IsEqual(const RecordRdata* other) const {
  50   if (other->Type() != Type()) return false;
  51   const SrvRecordRdata* srv_other = static_cast<const SrvRecordRdata*>(other);
  52   return weight_ == srv_other->weight_ &&
  53       port_ == srv_other->port_ &&
  54       priority_ == srv_other->priority_ &&
  55       target_ == srv_other->target_;
  56 }
  57
  58 ARecordRdata::ARecordRdata() {
  59 }
  60
  61 ARecordRdata::~ARecordRdata() {
  62 }
  63
  64 // static
  65 scoped_ptr<ARecordRdata> ARecordRdata::Create(
  66     const base::StringPiece& data,
  67     const DnsRecordParser& parser) {
  68   if (data.size() != kIPv4AddressSize)
  69     return scoped_ptr<ARecordRdata>();
  70
  71   scoped_ptr<ARecordRdata> rdata(new ARecordRdata);
  72
  73   rdata->address_.resize(kIPv4AddressSize);
  74   for (unsigned i = 0; i < kIPv4AddressSize; ++i) {
  75     rdata->address_[i] = data[i];
  76   }
  77
  78   return rdata.Pass();
  79 }
  80
  81 uint16 ARecordRdata::Type() const {
  82   return ARecordRdata::kType;
  83 }
  84
  85 bool ARecordRdata::IsEqual(const RecordRdata* other) const {
  86   if (other->Type() != Type()) return false;
  87   const ARecordRdata* a_other = static_cast<const ARecordRdata*>(other);
  88   return address_ == a_other->address_;
  89 }
  90
  91 AAAARecordRdata::AAAARecordRdata() {
  92 }
  93
  94 AAAARecordRdata::~AAAARecordRdata() {
  95 }
  96
  97 // static
  98 scoped_ptr<AAAARecordRdata> AAAARecordRdata::Create(
  99     const base::StringPiece& data,
 100     const DnsRecordParser& parser) {
 101   if (data.size() != kIPv6AddressSize)
 102     return scoped_ptr<AAAARecordRdata>();
 103
 104   scoped_ptr<AAAARecordRdata> rdata(new AAAARecordRdata);
 105
 106   rdata->address_.resize(kIPv6AddressSize);
 107   for (unsigned i = 0; i < kIPv6AddressSize; ++i) {
 108     rdata->address_[i] = data[i];
 109   }
 110
 111   return rdata.Pass();
 112 }
 113
 114 uint16 AAAARecordRdata::Type() const {
 115   return AAAARecordRdata::kType;
 116 }
 117
 118 bool AAAARecordRdata::IsEqual(const RecordRdata* other) const {
 119   if (other->Type() != Type()) return false;
 120   const AAAARecordRdata* a_other = static_cast<const AAAARecordRdata*>(other);
 121   return address_ == a_other->address_;
 122 }
 123
 124 CnameRecordRdata::CnameRecordRdata() {
 125 }
 126
 127 CnameRecordRdata::~CnameRecordRdata() {
 128 }
 129
 130 // static
 131 scoped_ptr<CnameRecordRdata> CnameRecordRdata::Create(
 132     const base::StringPiece& data,
 133     const DnsRecordParser& parser) {
 134   scoped_ptr<CnameRecordRdata> rdata(new CnameRecordRdata);
 135
 136   if (!parser.ReadName(data.begin(), &rdata->cname_))
 137     return scoped_ptr<CnameRecordRdata>();
 138
 139   return rdata.Pass();
 140 }
 141
 142 uint16 CnameRecordRdata::Type() const {
 143   return CnameRecordRdata::kType;
 144 }
 145
 146 bool CnameRecordRdata::IsEqual(const RecordRdata* other) const {
 147   if (other->Type() != Type()) return false;
 148   const CnameRecordRdata* cname_other =
 149       static_cast<const CnameRecordRdata*>(other);
 150   return cname_ == cname_other->cname_;
 151 }
 152
 153 PtrRecordRdata::PtrRecordRdata() {
 154 }
 155
 156 PtrRecordRdata::~PtrRecordRdata() {
 157 }
 158
 159 // static
 160 scoped_ptr<PtrRecordRdata> PtrRecordRdata::Create(
 161     const base::StringPiece& data,
 162     const DnsRecordParser& parser) {
 163   scoped_ptr<PtrRecordRdata> rdata(new PtrRecordRdata);
 164
 165   if (!parser.ReadName(data.begin(), &rdata->ptrdomain_))
 166     return scoped_ptr<PtrRecordRdata>();
 167
 168   return rdata.Pass();
 169 }
 170
 171 uint16 PtrRecordRdata::Type() const {
 172   return PtrRecordRdata::kType;
 173 }
 174
 175 bool PtrRecordRdata::IsEqual(const RecordRdata* other) const {
 176   if (other->Type() != Type()) return false;
 177   const PtrRecordRdata* ptr_other = static_cast<const PtrRecordRdata*>(other);
 178   return ptrdomain_ == ptr_other->ptrdomain_;
 179 }
 180
 181 TxtRecordRdata::TxtRecordRdata() {
 182 }
 183
 184 TxtRecordRdata::~TxtRecordRdata() {
 185 }
 186
 187 // static
 188 scoped_ptr<TxtRecordRdata> TxtRecordRdata::Create(
 189     const base::StringPiece& data,
 190     const DnsRecordParser& parser) {
 191   scoped_ptr<TxtRecordRdata> rdata(new TxtRecordRdata);
 192
 193   for (size_t i = 0; i < data.size(); ) {
 194     uint8 length = data[i];
 195
 196     if (i + length >= data.size())
 197       return scoped_ptr<TxtRecordRdata>();
 198
 199     rdata->texts_.push_back(data.substr(i + 1, length).as_string());
 200
 201     // Move to the next string.
 202     i += length + 1;
 203   }
 204
 205   return rdata.Pass();
 206 }
 207
 208 uint16 TxtRecordRdata::Type() const {
 209   return TxtRecordRdata::kType;
 210 }
 211
 212 bool TxtRecordRdata::IsEqual(const RecordRdata* other) const {
 213   if (other->Type() != Type()) return false;
 214   const TxtRecordRdata* txt_other = static_cast<const TxtRecordRdata*>(other);
 215   return texts_ == txt_other->texts_;
 216 }
 217
 218 NsecRecordRdata::NsecRecordRdata() {
 219 }
 220
 221 NsecRecordRdata::~NsecRecordRdata() {
 222 }
 223
 224 // static
 225 scoped_ptr<NsecRecordRdata> NsecRecordRdata::Create(
 226     const base::StringPiece& data,
 227     const DnsRecordParser& parser) {
 228   scoped_ptr<NsecRecordRdata> rdata(new NsecRecordRdata);
 229
 230   // Read the "next domain". This part for the NSEC record format is
 231   // ignored for mDNS, since it has no semantic meaning.
 232   unsigned next_domain_length = parser.ReadName(data.data(), NULL);
 233
 234   // If we did not succeed in getting the next domain or the data length
 235   // is too short for reading the bitmap header, return.
 236   if (next_domain_length == 0 || data.length() < next_domain_length + 2)
 237     return scoped_ptr<NsecRecordRdata>();
 238
 239   struct BitmapHeader {
 240     uint8 block_number;  // The block number should be zero.
 241     uint8 length;  // Bitmap length in bytes. Between 1 and 32.
 242   };
 243
 244   const BitmapHeader* header = reinterpret_cast<const BitmapHeader*>(
 245       data.data() + next_domain_length);
 246
 247   // The block number must be zero in mDns-specific NSEC records. The bitmap
 248   // length must be between 1 and 32.
 249   if (header->block_number != 0 || header->length == 0 || header->length > 32)
 250     return scoped_ptr<NsecRecordRdata>();
 251
 252   base::StringPiece bitmap_data = data.substr(next_domain_length + 2);
 253
 254   // Since we may only have one block, the data length must be exactly equal to
 255   // the domain length plus bitmap size.
 256   if (bitmap_data.length() != header->length)
 257     return scoped_ptr<NsecRecordRdata>();
 258
 259   rdata->bitmap_.insert(rdata->bitmap_.begin(),
 260                         bitmap_data.begin(),
 261                         bitmap_data.end());
 262
 263   return rdata.Pass();
 264 }
 265
 266 uint16 NsecRecordRdata::Type() const {
 267   return NsecRecordRdata::kType;
 268 }
 269
 270 bool NsecRecordRdata::IsEqual(const RecordRdata* other) const {
 271   if (other->Type() != Type())
 272     return false;
 273   const NsecRecordRdata* nsec_other =
 274       static_cast<const NsecRecordRdata*>(other);
 275   return bitmap_ == nsec_other->bitmap_;
 276 }
 277
 278 bool NsecRecordRdata::GetBit(unsigned i) const {
 279   unsigned byte_num = i/8;
 280   if (bitmap_.size() < byte_num + 1)
 281     return false;
 282
 283   unsigned bit_num = 7 - i % 8;
 284   return (bitmap_[byte_num] & (1 << bit_num)) != 0;
 285 }
 286
 287 }  // namespace net