/*
  LoRaWAN.h - Library header file for LoRaWAN protocol, uses RFM95W module
  Created by Leo Korbee, March 31, 2018.
  Released into the public domain.
  @license Attribution-NonCommercial-ShareAlike 4.0 International (CC BY-NC-SA 4.0)
  Thanks to all the folks who contributed before me on this code.

*/

#include "RFM95.h"
#include "Arduino.h"

#ifndef LoRaWAN_h
#define LoRaWAN_h


// for AES encryption
static const unsigned char PROGMEM S_Table[16][16] = {
  {0x63,0x7C,0x77,0x7B,0xF2,0x6B,0x6F,0xC5,0x30,0x01,0x67,0x2B,0xFE,0xD7,0xAB,0x76},
  {0xCA,0x82,0xC9,0x7D,0xFA,0x59,0x47,0xF0,0xAD,0xD4,0xA2,0xAF,0x9C,0xA4,0x72,0xC0},
  {0xB7,0xFD,0x93,0x26,0x36,0x3F,0xF7,0xCC,0x34,0xA5,0xE5,0xF1,0x71,0xD8,0x31,0x15},
  {0x04,0xC7,0x23,0xC3,0x18,0x96,0x05,0x9A,0x07,0x12,0x80,0xE2,0xEB,0x27,0xB2,0x75},
  {0x09,0x83,0x2C,0x1A,0x1B,0x6E,0x5A,0xA0,0x52,0x3B,0xD6,0xB3,0x29,0xE3,0x2F,0x84},
  {0x53,0xD1,0x00,0xED,0x20,0xFC,0xB1,0x5B,0x6A,0xCB,0xBE,0x39,0x4A,0x4C,0x58,0xCF},
  {0xD0,0xEF,0xAA,0xFB,0x43,0x4D,0x33,0x85,0x45,0xF9,0x02,0x7F,0x50,0x3C,0x9F,0xA8},
  {0x51,0xA3,0x40,0x8F,0x92,0x9D,0x38,0xF5,0xBC,0xB6,0xDA,0x21,0x10,0xFF,0xF3,0xD2},
  {0xCD,0x0C,0x13,0xEC,0x5F,0x97,0x44,0x17,0xC4,0xA7,0x7E,0x3D,0x64,0x5D,0x19,0x73},
  {0x60,0x81,0x4F,0xDC,0x22,0x2A,0x90,0x88,0x46,0xEE,0xB8,0x14,0xDE,0x5E,0x0B,0xDB},
  {0xE0,0x32,0x3A,0x0A,0x49,0x06,0x24,0x5C,0xC2,0xD3,0xAC,0x62,0x91,0x95,0xE4,0x79},
  {0xE7,0xC8,0x37,0x6D,0x8D,0xD5,0x4E,0xA9,0x6C,0x56,0xF4,0xEA,0x65,0x7A,0xAE,0x08},
  {0xBA,0x78,0x25,0x2E,0x1C,0xA6,0xB4,0xC6,0xE8,0xDD,0x74,0x1F,0x4B,0xBD,0x8B,0x8A},
  {0x70,0x3E,0xB5,0x66,0x48,0x03,0xF6,0x0E,0x61,0x35,0x57,0xB9,0x86,0xC1,0x1D,0x9E},
  {0xE1,0xF8,0x98,0x11,0x69,0xD9,0x8E,0x94,0x9B,0x1E,0x87,0xE9,0xCE,0x55,0x28,0xDF},
  {0x8C,0xA1,0x89,0x0D,0xBF,0xE6,0x42,0x68,0x41,0x99,0x2D,0x0F,0xB0,0x54,0xBB,0x16}
};


class LoRaWAN
{
  public:
    LoRaWAN(RFM95 &rfm95);
    void setKeys(unsigned char NwkSkey[], unsigned char AppSkey[], unsigned char DevAddr[]);
    void Send_Data(unsigned char *Data, unsigned char Data_Length, unsigned int Frame_Counter_Tx);

  private:
    RFM95 *_rfm95;
    // remember arrays are pointers!
    unsigned char *_NwkSkey;
    unsigned char *_AppSkey;
    unsigned char *_DevAddr;

    void RFM_Send_Package(unsigned char *RFM_Tx_Package, unsigned char Package_Length);
    // security stuff:
    void Encrypt_Payload(unsigned char *Data, unsigned char Data_Length, unsigned int Frame_Counter, unsigned char Direction);
    void Calculate_MIC(unsigned char *Data, unsigned char *Final_MIC, unsigned char Data_Length, unsigned int Frame_Counter, unsigned char Direction);
    void Generate_Keys(unsigned char *K1, unsigned char *K2);
    void Shift_Left(unsigned char *Data);
    void XOR(unsigned char *New_Data,unsigned char *Old_Data);
    void AES_Encrypt(unsigned char *Data, unsigned char *Key);
    void AES_Add_Round_Key(unsigned char *Round_Key, unsigned char (*State)[4]);
    unsigned char AES_Sub_Byte(unsigned char Byte);
    void AES_Shift_Rows(unsigned char (*State)[4]);
    void AES_Mix_Collums(unsigned char (*State)[4]);
    void AES_Calculate_Round_Key(unsigned char Round, unsigned char *Round_Key);


};


#endif
