xxtea_encryption.h

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#pragma once
 
#include "esphome/core/defines.h"
#ifdef USE_PACKET_INTERFACE_XXTEA
#include <array>
#include <initializer_list>
 
#include "esphome/core/preferences.h"
#include "packet_interface.h"
 
namespace esphome::packet_interface {
 
class XxteaEncryption : public PacketInterface {
 public:
  XxteaEncryption(PacketInterface *lower, bool rolling_code);
 
  void setup() override;
  void dump_config() override;
  bool send_to_interface(const PacketBuffer &data, const PacketMetaData &meta_data) override;
 
  void set_key(std::initializer_list<uint32_t> key);
 
 protected:
  void receive_(const PacketBuffer &data, const PacketMetaData &meta_data);
  bool accept_counter_(uint32_t boot, uint32_t counter);
  void next_boot_();
 
  PacketInterface *lower_;
  const size_t trailer_size_;
  std::array<uint32_t, 8> key_{};
  // Separate buffers, as a layer above may send a reply while a received packet is being passed up; both are in one
  // block allocated in setup(), and tx_buffer_ stays null if that fails
  uint32_t *tx_buffer_{nullptr};
  uint32_t *rx_buffer_{nullptr};
  ESPPreferenceObject pref_;
  uint32_t boot_{0};
  uint32_t counter_{0};
  uint32_t peer_boot_{0};
  uint32_t peer_counter_{0};
  uint32_t echo_boot_{0};  // highest boot number heard from the peer
  bool peer_seen_{false};
  bool old_boot_warned_{false};
  const bool rolling_code_;
};
 
}  // namespace esphome::packet_interface
#endif