nack.hpp

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#ifndef NDNPH_PACKET_NACK_HPP
#define NDNPH_PACKET_NACK_HPP
 
#include "interest.hpp"
 
namespace ndnph {
 
enum class NackReason : uint8_t {
  None = 0,
  Congestion = 1,
  Duplicate = 2,
  NoRoute = 3,
  Unspecified = 7,
};
 
class NackHeader : public RefRegion<detail::InterestObj> {
public:
  using MaxSize = std::integral_constant<size_t, 3 + 1 + 3 + 1 + 1>;
 
  using RefRegion::RefRegion;
 
  NackReason getReason() const {
    return static_cast<NackReason>(obj->nackReason);
  }
 
  void setReason(NackReason v) {
    obj->nackReason = static_cast<uint8_t>(v);
  }
 
  void encodeTo(Encoder& encoder) const {
    auto reason = getReason();
    encoder.prependTlv(TT::Nack, [reason](Encoder& encoder) {
      if (reason != NackReason::Unspecified) {
        encoder.prependTlv(TT::NackReason, tlv::NNI(encodeNackReason(reason)));
      }
    });
  }
 
  bool decodeFrom(const Decoder::Tlv& input) {
    uint64_t nackReasonV = 0;
    bool ok = EvDecoder::decode(input, {TT::Nack}, EvDecoder::defNni<TT::NackReason>(&nackReasonV));
    if (ok) {
      obj->nackReason = static_cast<uint8_t>(decodeNackReason(nackReasonV));
    }
    return ok;
  }
 
private:
  static uint64_t encodeNackReason(NackReason v) {
    return static_cast<uint64_t>(v) * 50;
  }
 
  static NackReason decodeNackReason(uint64_t v) {
    switch (v) {
      case 50:
      case 100:
      case 150:
        return static_cast<NackReason>(v / 50);
      default:
        return NackReason::Unspecified;
    }
  }
};
 
class Nack : public RefRegion<detail::InterestObj> {
public:
  using RefRegion::RefRegion;
 
  NackHeader getHeader() const {
    return NackHeader(obj);
  }
 
  NackReason getReason() const {
    return getHeader().getReason();
  }
 
  Interest getInterest() const {
    return Interest(obj);
  }
 
  static Nack create(Interest interest, NackReason reason) {
    Region& region = regionOf(interest);
    Nack nack = region.create<Nack>();
    if (nack) {
      nack.getHeader().setReason(reason);
      auto ni = nack.getInterest();
      ni.setName(interest.getName());
      ni.setCanBePrefix(interest.getCanBePrefix());
      ni.setMustBeFresh(interest.getMustBeFresh());
      ni.setNonce(interest.getNonce());
    }
    return nack;
  }
};
 
} // namespace ndnph
 
#endif // NDNPH_PACKET_NACK_HPP