include/linux/mpi.h

   1 /* SPDX-License-Identifier: GPL-2.0-or-later */
   2 /* mpi.h  -  Multi Precision Integers
   3  *      Copyright (C) 1994, 1996, 1998, 1999,
   4  *                    2000, 2001 Free Software Foundation, Inc.
   5  *
   6  * This file is part of GNUPG.
   7  *
   8  * Note: This code is heavily based on the GNU MP Library.
   9  *       Actually it's the same code with only minor changes in the
  10  *       way the data is stored; this is to support the abstraction
  11  *       of an optional secure memory allocation which may be used
  12  *       to avoid revealing of sensitive data due to paging etc.
  13  *       The GNU MP Library itself is published under the LGPL;
  14  *       however I decided to publish this code under the plain GPL.
  15  */
  16
  17 #ifndef G10_MPI_H
  18 #define G10_MPI_H
  19
  20 #include <linux/types.h>
  21 #include <linux/scatterlist.h>
  22
  23 #define BYTES_PER_MPI_LIMB      (BITS_PER_LONG / 8)
  24 #define BITS_PER_MPI_LIMB       BITS_PER_LONG
  25
  26 typedef unsigned long int mpi_limb_t;
  27 typedef signed long int mpi_limb_signed_t;
  28
  29 struct gcry_mpi {
  30         int alloced;            /* array size (# of allocated limbs) */
  31         int nlimbs;             /* number of valid limbs */
  32         int nbits;              /* the real number of valid bits (info only) */
  33         int sign;               /* indicates a negative number */
  34         unsigned flags;         /* bit 0: array must be allocated in secure memory space */
  35         /* bit 1: not used */
  36         /* bit 2: the limb is a pointer to some m_alloced data */
  37         mpi_limb_t *d;          /* array with the limbs */
  38 };
  39
  40 typedef struct gcry_mpi *MPI;
  41
  42 #define mpi_get_nlimbs(a)     ((a)->nlimbs)
  43
  44 /*-- mpiutil.c --*/
  45 MPI mpi_alloc(unsigned nlimbs);
  46 void mpi_free(MPI a);
  47 int mpi_resize(MPI a, unsigned nlimbs);
  48
  49 MPI mpi_copy(MPI a);
  50
  51 /*-- mpicoder.c --*/
  52 MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
  53 MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
  54 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
  55 void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
  56 int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
  57                     int *sign);
  58 int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
  59                      int *sign);
  60
  61 /*-- mpi-mod.c --*/
  62 int mpi_mod(MPI rem, MPI dividend, MPI divisor);
  63
  64 /*-- mpi-pow.c --*/
  65 int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
  66
  67 /*-- mpi-cmp.c --*/
  68 int mpi_cmp_ui(MPI u, ulong v);
  69 int mpi_cmp(MPI u, MPI v);
  70
  71 /*-- mpi-sub-ui.c --*/
  72 int mpi_sub_ui(MPI w, MPI u, unsigned long vval);
  73
  74 /*-- mpi-bit.c --*/
  75 void mpi_normalize(MPI a);
  76 unsigned mpi_get_nbits(MPI a);
  77 int mpi_test_bit(MPI a, unsigned int n);
  78 int mpi_set_bit(MPI a, unsigned int n);
  79 int mpi_rshift(MPI x, MPI a, unsigned int n);
  80
  81 /*-- mpi-add.c --*/
  82 int mpi_add(MPI w, MPI u, MPI v);
  83 int mpi_sub(MPI w, MPI u, MPI v);
  84 int mpi_addm(MPI w, MPI u, MPI v, MPI m);
  85 int mpi_subm(MPI w, MPI u, MPI v, MPI m);
  86
  87 /*-- mpi-mul.c --*/
  88 int mpi_mul(MPI w, MPI u, MPI v);
  89 int mpi_mulm(MPI w, MPI u, MPI v, MPI m);
  90
  91 /*-- mpi-div.c --*/
  92 int mpi_tdiv_r(MPI rem, MPI num, MPI den);
  93 int mpi_fdiv_r(MPI rem, MPI dividend, MPI divisor);
  94
  95 /* inline functions */
  96
  97 /**
  98  * mpi_get_size() - returns max size required to store the number
  99  *
 100  * @a:  A multi precision integer for which we want to allocate a buffer
 101  *
 102  * Return: size required to store the number
 103  */
 104 static inline unsigned int mpi_get_size(MPI a)
 105 {
 106         return a->nlimbs * BYTES_PER_MPI_LIMB;
 107 }
 108 #endif /*G10_MPI_H */