Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2020 Project CHIP Authors
       4              :  *
       5              :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6              :  *    you may not use this file except in compliance with the License.
       7              :  *    You may obtain a copy of the License at
       8              :  *
       9              :  *        http://www.apache.org/licenses/LICENSE-2.0
      10              :  *
      11              :  *    Unless required by applicable law or agreed to in writing, software
      12              :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13              :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14              :  *    See the License for the specific language governing permissions and
      15              :  *    limitations under the License.
      16              :  */
      17              : 
      18              : #pragma once
      19              : 
      20              : #include <string.h>
      21              : 
      22              : #include <lib/dnssd/minimal_mdns/records/ResourceRecord.h>
      23              : 
      24              : namespace mdns {
      25              : namespace Minimal {
      26              : 
      27              : class TxtResourceRecord : public ResourceRecord
      28              : {
      29              : public:
      30              :     static constexpr uint64_t kDefaultTtl = 4500; // 75 minutes
      31              : 
      32              :     TxtResourceRecord(const FullQName & qName, const char ** entries, size_t entryCount) :
      33              :         ResourceRecord(QType::TXT, qName), mEntries(entries), mEntryCount(entryCount)
      34              :     {
      35              :         SetTtl(kDefaultTtl);
      36              :     }
      37              : 
      38              :     template <size_t N>
      39              :     TxtResourceRecord(const FullQName & qName, const char * (&entries)[N]) :
      40              :         ResourceRecord(QType::TXT, qName), mEntries(entries), mEntryCount(N)
      41              :     {
      42              :         SetTtl(kDefaultTtl);
      43              :     }
      44              : 
      45              :     // A FullQName is a holder of a string array.
      46            7 :     TxtResourceRecord(const FullQName & qName, FullQName entries) :
      47            7 :         ResourceRecord(QType::TXT, qName), mEntries(entries.names), mEntryCount(entries.nameCount)
      48              :     {
      49            7 :         SetTtl(kDefaultTtl);
      50            7 :     }
      51              :     size_t GetNumEntries() const { return mEntryCount; }
      52              :     const char * const * GetEntries() const { return mEntries; }
      53              : 
      54              : protected:
      55           42 :     bool WriteData(RecordWriter & out) const override
      56              :     {
      57          252 :         for (size_t i = 0; i < mEntryCount; i++)
      58              :         {
      59          210 :             size_t len = strlen(mEntries[i]);
      60          210 :             if (len > kMaxTxtRecordLength)
      61              :             {
      62            0 :                 return false;
      63              :             }
      64              : 
      65          210 :             out.Put8(static_cast<uint8_t>(len)).PutString(mEntries[i]);
      66              :         }
      67           42 :         return out.Fit();
      68              :     }
      69              : 
      70              : private:
      71              :     const char * const * mEntries;
      72              :     const size_t mEntryCount;
      73              : 
      74              :     static constexpr size_t kMaxTxtRecordLength = 63;
      75              : };
      76              : 
      77              : } // namespace Minimal
      78              : } // namespace mdns