1 /* mpi.h  -  Multi Precision Integers
2  *	Copyright (C) 1994, 1996, 1998, 1999,
3  *                    2000, 2001 Free Software Foundation, Inc.
4  *
5  * This file is part of GNUPG.
6  *
7  * GNUPG is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * GNUPG is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  *
17  * You should have received a copy of the GNU General Public License
18  * along with this program; if not, write to the Free Software
19  * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
20  *
21  * Note: This code is heavily based on the GNU MP Library.
22  *	 Actually it's the same code with only minor changes in the
23  *	 way the data is stored; this is to support the abstraction
24  *	 of an optional secure memory allocation which may be used
25  *	 to avoid revealing of sensitive data due to paging etc.
26  *	 The GNU MP Library itself is published under the LGPL;
27  *	 however I decided to publish this code under the plain GPL.
28  */
29 
30 #ifndef G10_MPI_H
31 #define G10_MPI_H
32 
33 #include <linux/types.h>
34 #include <linux/scatterlist.h>
35 
36 #define BYTES_PER_MPI_LIMB	(BITS_PER_LONG / 8)
37 #define BITS_PER_MPI_LIMB	BITS_PER_LONG
38 
39 typedef unsigned long int mpi_limb_t;
40 typedef signed long int mpi_limb_signed_t;
41 
42 struct gcry_mpi {
43 	int alloced;		/* array size (# of allocated limbs) */
44 	int nlimbs;		/* number of valid limbs */
45 	int nbits;		/* the real number of valid bits (info only) */
46 	int sign;		/* indicates a negative number */
47 	unsigned flags;		/* bit 0: array must be allocated in secure memory space */
48 	/* bit 1: not used */
49 	/* bit 2: the limb is a pointer to some m_alloced data */
50 	mpi_limb_t *d;		/* array with the limbs */
51 };
52 
53 typedef struct gcry_mpi *MPI;
54 
55 #define mpi_get_nlimbs(a)     ((a)->nlimbs)
56 
57 /*-- mpiutil.c --*/
58 MPI mpi_alloc(unsigned nlimbs);
59 void mpi_free(MPI a);
60 int mpi_resize(MPI a, unsigned nlimbs);
61 
62 /*-- mpicoder.c --*/
63 MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes);
64 MPI mpi_read_from_buffer(const void *buffer, unsigned *ret_nread);
65 MPI mpi_read_raw_from_sgl(struct scatterlist *sgl, unsigned int len);
66 void *mpi_get_buffer(MPI a, unsigned *nbytes, int *sign);
67 int mpi_read_buffer(MPI a, uint8_t *buf, unsigned buf_len, unsigned *nbytes,
68 		    int *sign);
69 int mpi_write_to_sgl(MPI a, struct scatterlist *sg, unsigned nbytes,
70 		     int *sign);
71 
72 /*-- mpi-pow.c --*/
73 int mpi_powm(MPI res, MPI base, MPI exp, MPI mod);
74 
75 /*-- mpi-cmp.c --*/
76 int mpi_cmp_ui(MPI u, ulong v);
77 int mpi_cmp(MPI u, MPI v);
78 
79 /*-- mpi-bit.c --*/
80 void mpi_normalize(MPI a);
81 unsigned mpi_get_nbits(MPI a);
82 
83 /* inline functions */
84 
85 /**
86  * mpi_get_size() - returns max size required to store the number
87  *
88  * @a:	A multi precision integer for which we want to allocate a bufer
89  *
90  * Return: size required to store the number
91  */
mpi_get_size(MPI a)92 static inline unsigned int mpi_get_size(MPI a)
93 {
94 	return a->nlimbs * BYTES_PER_MPI_LIMB;
95 }
96 #endif /*G10_MPI_H */
97