bool SixLowPanNetDevice::FindMulticastCompressionContext()

in simulation/src/sixlowpan/model/sixlowpan-net-device.cc [2784:2827]

• 35 lines of code
• 14 McCabe index (conditional complexity)

bool SixLowPanNetDevice::FindMulticastCompressionContext (Ipv6Address address, uint8_t& contextId)
{
  NS_LOG_FUNCTION (this << address);

  // The only allowed context-based compressed multicast address is in the form
  // ffXX:XXLL:PPPP:PPPP:PPPP:PPPP:XXXX:XXXX

  for (const auto& iter: m_contextTable)
    {
      ContextEntry context = iter.second;

      if ( (context.compressionAllowed == true) && (context.validLifetime > Simulator::Now ()) )
        {
          uint8_t contextLength = context.contextPrefix.GetPrefixLength ();

          if (contextLength <= 64) // only 64-bit prefixes or less are allowed.
            {
              uint8_t contextBytes[16];
              uint8_t addressBytes[16];

              context.contextPrefix.GetBytes (contextBytes);
              address.GetBytes (addressBytes);

              if (addressBytes[3] == contextLength &&
                  addressBytes[4] == contextBytes[0] &&
                  addressBytes[5] == contextBytes[1] &&
                  addressBytes[6] == contextBytes[2] &&
                  addressBytes[7] == contextBytes[3] &&
                  addressBytes[8] == contextBytes[4] &&
                  addressBytes[9] == contextBytes[5] &&
                  addressBytes[10] == contextBytes[6] &&
                  addressBytes[11] == contextBytes[7])
                {
                  NS_LOG_LOGIC ("Fount context " << +contextId << " " <<
                                Ipv6Address::GetOnes ().CombinePrefix (context.contextPrefix) << context.contextPrefix << " matching");

                  contextId = iter.first;
                  return true;
                }
            }
        }
    }
  return false;
}