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 /*-- mpicoder.c --*/
  50 MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
  51 MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
  52 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
  53 void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
  54 int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
  55                     int *sign);
  56 int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
  57                      int *sign);
  58
  59 /*-- mpi-pow.c --*/
  60 int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
  61
  62 /*-- mpi-cmp.c --*/
  63 int mpi_cmp_ui(MPI u, ulong v);
  64 int mpi_cmp(MPI u, MPI v);
  65
  66 /*-- mpi-bit.c --*/
  67 void mpi_normalize(MPI a);
  68 unsigned mpi_get_nbits(MPI a);
  69
  70 /* inline functions */
  71
  72 /**
  73  * mpi_get_size() - returns max size required to store the number
  74  *
  75  * @a:  A multi precision integer for which we want to allocate a bufer
  76  *
  77  * Return: size required to store the number
  78  */
  79 static inline unsigned int mpi_get_size(MPI a)
  80 {
  81         return a->nlimbs * BYTES_PER_MPI_LIMB;
  82 }
  83 #endif /*G10_MPI_H */