// ========================================================================================================
// ========================================================================================================
// *********************************************** common.h ***********************************************
// ========================================================================================================
// ========================================================================================================

#include <unistd.h>
#include <fcntl.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>  
#include <sys/mman.h>

#include <sys/types.h>
#include <sys/socket.h>
#include <arpa/inet.h> 
#include <netdb.h> 

#include <time.h>
#include <sys/time.h>

#include <pthread.h>

// =====================================================================================================================
// =====================================================================================================================
// COMMON PARAMETERS for verifier_regeneration.c and token_regeneration.c

// Tune these as needed to the desired key size for SessionEncryption (SE) and KEK.
#define SE_TARGET_NUM_KEY_BITS 512
#define KEK_TARGET_NUM_KEY_BITS 2000

// NOTE: THIS PARAMETER IS HARDCODED TO SKE 5 IN THE VHDL SO SETTING THIS TO 0 HAS NOT EFFECT. LEAVE IT AT 1.
// Recommended value for SKE_3_or_5 is 1. Secure key encoding level as given here protects against bit flip errors when
// HELP is configured to carry out the KEK function. MUST BE SET TO 0 or 1. Setting to 1 provides a higher level of 
// protection but generates more helper data. Used only in token_regeneration.c.
#define SKE_3_OR_5 1

// Specify minimum number of bits that must be generated for token and verifier authentication to succeed. Currently,
// all bits in the generated bitstrings must match in order for authenication to be classified as successful. This restriction
// can be relaxed as needed with appropriate changes in the TokenAuthenication and VerifierAuthenication functions.
#define AUTHEN_MIN_BITSTRING_SIZE 80

// Recommended offset mode is 4. There are 5 basic Offset modes: 0) no Offset, 1) random Offset, 2) Population Offset,
// 3) PerChip Offset and 4) both Population and PerChip Offset. The difference in these modes is described in the documentation.
// !!! WARNING: DO NOT USE 1) Random Offsets with the multi-threaded version in XWIN_VERSION -- the ComputeRandomOffset routine
// calls LFSR_11_A_bit_low which uses a static variable and so it will get corrupted!
// Made this a parameter.
//#define OFFSET_MODE 4

// THIS MUST REMAIN AT 4. VHDL code is hardcoded with 4 bits.
#define OFFSET_RESOLUTION_BITS 4

// Recommendation is to set this parameter to 0. For testing purposes, it can be set to 1 to disable random (XOR_nonce) 
// selection of the HELP parameters, and instead to force the HELP parameters to remain constant for all innocations. 
// The fixed values used for the HELP parameters can be specified below, see constants labelel with prefix 'FIXED_'.
// Made this a parameter.
//#define FIX_PARAMS 0

// These 'FIXED_' parameters are ONLY used when the flag 'FIX_PARAMS' is set to 1.
// Constraint: Values assigned for the LFSR seeds must be >= 0 and <= 2047
#define FIXED_LFSR_SEED_LOW 0
#define FIXED_LFSR_SEED_HIGH 0

// Constraint: Values assigned for the mean must be >= -500 and <= 500
#define FIXED_REFERENCE_MEAN -18.0

// Constraint: Values for range must be > 0 (NOTE: if set to 0, the HELP Engine will be disabled and will return to idle) and <= 500.
#define FIXED_REFERENCE_RANGE 168.0

// Constraint: Values for modulus must be > 0 and <= 30, and is further constrained by the value assigned to FIXED_MODULUS, i.e., 
//    FIXED_MODULUS >= 4*FIXED_MARGIN + 2. 
// (NOTE: if less than this minimum value, the HELP Engine will be disabled and will return to idle).
#define FIXED_MODULUS 16.0
//#define FIXED_MODULUS 12.0

// Constraint: Values for Margin must be >= 0 and <= 5, and has additional constraints as specified for FIXED_MODULUS above.
//#define FIXED_MARGIN 0.0
//#define FIXED_MARGIN 1.0
//#define FIXED_MARGIN 2.0
#define FIXED_MARGIN 3.0

// =====================================================================================================================
// =====================================================================================================================

// MAX_VECS MUST be equal or larger than vector set.
#define MAX_VECS 1500
#define MAX_SAMS 128

// Scratch pad string size
#define MAX_STRING_LEN 2000

// Entropy source datapath characteristics for processing vectors on the token side. 
#define VEC_LEN_BITS 64
#define MAX_OUTPUTS 64
#define VEC_CHUNK_SIZE 16

#define MAX_BINARY_BYTES 500
#define MAX_NONCE_BYTES 40

// MAX that the HELP Engine can generate before overflow (where further nonce bytes are ignored).
#define MAX_GENERATED_NONCE_BYTES 10000

// Use upto the larger of the number of rising or falling PNs. Usually just set to 2048 (NOTE: rising and falling
// PNs are stored now in separate arrays so this refers to the number of each, NOT THE SUM of the two.
// BYTE-TO-WORD: NOTE: ALL CONSTANTS HERE MUST BE AN EVEN NUMBER, in particular, MAX_PNDIFFS.
#define MAX_PNS 2048
#define MAX_PNDIFFS 2048

// NOTE: This is the range I'm using in the hardware. I find the largest negative value in the distribution, subtract
// that from all values (shifting the distribution left for negative largest values and right for positive). The
// binning of values therefore starts at bin 0 and goes up through the largest positive value (minus the negative value).
// Distribution ranges are typically between 250 to 300. In the hardware, I also preserve 1 digit of precision, which is
// equivalent to multiplying the range by 2. I also do this on the server to get extra precision out of the range.
#define DIST_RANGE 1024

// Represents +6.25% and -93.75% since NUMBER of PNDIFFS is 2048. Given w.r.t. NUM_PNDIFFS defined above.
#define RANGE_LOW_LIMIT 128
#define RANGE_HIGH_LIMIT 1920

// For checks that the hardware version is not overflowing.
#define LARGEST_POS_VAL (16384/16) - 1
#define LARGEST_NEG_VAL -LARGEST_POS_VAL

// =====================================================================================================================
// =====================================================================================================================
int OpenSocketServer(int str_length, int *server_socket_desc_ptr, char server_IP[str_length], 
   int port_number, int *client_socket_desc_ptr, struct sockaddr_in *client_addr_ptr, 
   int accept_only, int check_and_return);

void OpenSocketClient(int str_length, char server_IP[str_length], int port_number, 
   int *server_socket_desc_ptr);

int SockGetB(unsigned char *buffer, int buffer_size, int socket_desc);

int SockSendB(unsigned char *buffer, int buffer_size, int socket_desc);

void PrintHeaderAndHexVals(int max_string_len, char header_str[max_string_len], int max_vals, 
   int num_vals, unsigned char vals[max_vals], int max_vals_per_row);