[catacomb] / symm / ofb-def.h

/* -*-c-*-
 *
 * Definitions for output feedback mode
 *
 * (c) 1999 Straylight/Edgeware
 */

/*----- Licensing notice --------------------------------------------------*
 *
 * This file is part of Catacomb.
 *
 * Catacomb is free software; you can redistribute it and/or modify
 * it under the terms of the GNU Library General Public License as
 * published by the Free Software Foundation; either version 2 of the
 * License, or (at your option) any later version.
 *
 * Catacomb is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with Catacomb; if not, write to the Free
 * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
 * MA 02111-1307, USA.
 */

#ifndef CATACOMB_OFB_DEF_H
#define CATACOMB_OFB_DEF_H

#ifdef __cplusplus
  extern "C" {
#endif

/*----- Header files ------------------------------------------------------*/

#include <stdarg.h>
#include <string.h>

#include <mLib/bits.h>
#include <mLib/sub.h>

#ifndef CATACOMB_ARENA_H
#  include "arena.h"
#endif

#ifndef CATACOMB_BLKC_H
#  include "blkc.h"
#endif

#ifndef CATACOMB_GCIPHER_H
#  include "gcipher.h"
#endif

#ifndef CATACOMB_PARANOIA_H
#  include "paranoia.h"
#endif

/*----- Macros ------------------------------------------------------------*/

/* --- @OFB_DEF@ --- *
 *
 * Arguments:	@PRE@, @pre@ = prefixes for the underlying block cipher
 *
 * Use:		Creates definitions for output feedback mode.
 */

#define OFB_DEF(PRE, pre) OFB_DEFX(PRE, pre, #pre, #pre)

#define OFB_DEFX(PRE, pre, name, fname)					\
									\
/* --- @pre_ofbgetiv@ --- *						\
 *									\
 * Arguments:	@const pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@void *iv@ = pointer to output data block		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Reads the currently set IV.  Reading and setting an IV	\
 *		is not transparent to the cipher.  It will add a `step'	\
 *		which must be matched by a similar operation during	\
 *		decryption.						\
 */									\
									\
void pre##_ofbgetiv(const pre##_ofbctx *ctx, void *iv)			\
{									\
  octet *p = iv;							\
  unsigned off = ctx->off;						\
  unsigned rest = PRE##_BLKSZ - off;					\
									\
  memcpy(p, ctx->b + off, rest);					\
  memcpy(p + rest, ctx->b, off);					\
}									\
									\
/* --- @pre_ofbsetiv@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@cnost void *iv@ = pointer to IV to set			\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Sets the IV to use for subsequent encryption.		\
 */									\
									\
void pre##_ofbsetiv(pre##_ofbctx *ctx, const void *iv)			\
  { memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = PRE##_BLKSZ; }		\
									\
/* --- @pre_ofbbdry@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Inserts a boundary during encryption.  Successful	\
 *		decryption must place a similar boundary.		\
 */									\
									\
void pre##_ofbbdry(pre##_ofbctx *ctx)					\
{									\
  uint32 t[PRE##_BLKSZ/4];						\
									\
  BLKC_LOAD(PRE, t, ctx->b);						\
  pre##_eblk(&ctx->ctx, t, t);						\
  BLKC_STORE(PRE, ctx->b, t);						\
  ctx->off = PRE##_BLKSZ;						\
  BURN(t);								\
}									\
									\
/* --- @pre_ofbsetkey@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@const pre_ctx *k@ = pointer to cipher context		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Sets the OFB context to use a different cipher key.	\
 */									\
									\
void pre##_ofbsetkey(pre##_ofbctx *ctx, const pre##_ctx *k)		\
  { ctx->ctx = *k; }							\
									\
/* --- @pre_ofbinit@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to cipher context		\
 *		@const void *key@ = pointer to the key buffer		\
 *		@size_t sz@ = size of the key				\
 *		@const void *iv@ = pointer to initialization vector	\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Initializes a OFB context ready for use.  You should	\
 *		ensure that the IV chosen is unique: reusing an IV will	\
 *		compromise the security of the entire plaintext.  This	\
 *		is equivalent to calls to @pre_init@, @pre_ofbsetkey@	\
 *		and @pre_ofbsetiv@.					\
 */									\
									\
void pre##_ofbinit(pre##_ofbctx *ctx,					\
		     const void *key, size_t sz,			\
		     const void *iv)					\
{									\
  static const octet zero[PRE##_BLKSZ] = { 0 };				\
									\
  pre##_init(&ctx->ctx, key, sz);					\
  pre##_ofbsetiv(ctx, iv ? iv : zero);					\
}									\
									\
/* --- @pre_ofbencrypt@ --- *						\
 *									\
 * Arguments:	@pre_ofbctx *ctx@ = pointer to OFB context block	\
 *		@const void *src@ = pointer to source data		\
 *		@void *dest@ = pointer to destination data		\
 *		@size_t sz@ = size of block to be encrypted		\
 *									\
 * Returns:	---							\
 *									\
 * Use:		Encrypts or decrypts a block with a block cipher in OFB	\
 *		mode: encryption and decryption are the same in OFB.	\
 *		The destination may be null to just churn the feedback	\
 *		round for a bit.  The source may be null to use the	\
 *		cipher as a random data generator.			\
 */									\
									\
void pre##_ofbencrypt(pre##_ofbctx *ctx,				\
		      const void *src, void *dest,			\
		      size_t sz)					\
{									\
  const octet *s = src;							\
  octet *d = dest;							\
  unsigned off = ctx->off;						\
  uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4];				\
  octet y;								\
									\
  /* --- Empty blocks are trivial --- */				\
									\
  if (!sz) return;							\
									\
  /* --- If I can deal with the block from my buffer, do that --- */	\
									\
  if (sz < PRE##_BLKSZ - off) goto small;				\
									\
  /* --- Finish off what's left in my buffer --- */			\
									\
  if (!d) sz -= PRE##_BLKSZ - off;					\
  else while (off < PRE##_BLKSZ)					\
    { y = s ? *s++ : 0; *d++ = ctx->b[off++] ^ y; sz--; }		\
									\
  /* --- Main encryption loop --- */					\
									\
  BLKC_LOAD(PRE, t, ctx->b);						\
									\
  for (;;) {								\
    pre##_eblk(&ctx->ctx, t, t);					\
    if (sz < PRE##_BLKSZ) break;					\
    if (!d) /* do nothing */;						\
    else if (!s) { BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; }		\
    else {								\
      BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ;				\
      BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ;			\
    }									\
    sz -= PRE##_BLKSZ;							\
  }									\
									\
  BLKC_STORE(PRE, ctx->b, t);						\
  off = 0;								\
									\
  /* --- Tidying up the tail end --- */					\
									\
  if (sz) {								\
  small:								\
    if (!d) off += sz;							\
    else do { y = s ? *s++ : 0; *d++ = ctx->b[off++] ^ y; sz--; }	\
    while (sz);								\
  }									\
									\
  /* --- Done --- */							\
									\
  ctx->off = off;							\
  return;								\
}									\
									\
/* --- Generic cipher interface --- */					\
									\
static const gcipher_ops gops;						\
									\
typedef struct gctx {							\
  gcipher c;								\
  pre##_ofbctx k;							\
} gctx;									\
									\
static gcipher *ginit(const void *k, size_t sz)				\
{									\
  gctx *g = S_CREATE(gctx);						\
  g->c.ops = &gops;							\
  pre##_ofbinit(&g->k, k, sz, 0);					\
  return (&g->c);							\
}									\
									\
static void gencrypt(gcipher *c, const void *s, void *t, size_t sz)	\
  { gctx *g = (gctx *)c; pre##_ofbencrypt(&g->k, s, t, sz); }		\
									\
static void gdestroy(gcipher *c)					\
  { gctx *g = (gctx *)c; BURN(*g); S_DESTROY(g); }			\
									\
static void gsetiv(gcipher *c, const void *iv)				\
  { gctx *g = (gctx *)c; pre##_ofbsetiv(&g->k, iv); }			\
									\
static void gbdry(gcipher *c)						\
{									\
  gctx *g = (gctx *)c;							\
  pre##_ofbbdry(&g->k);							\
}									\
									\
static const gcipher_ops gops = {					\
  &pre##_ofb,								\
  gencrypt, gencrypt, gdestroy, gsetiv, gbdry				\
};									\
									\
const gccipher pre##_ofb = {						\
  name "-ofb", pre##_keysz, PRE##_BLKSZ,				\
  ginit									\
};									\
									\
/* --- Generic random number generator interface --- */			\
									\
typedef struct grctx {							\
  grand r;								\
  pre##_ofbctx k;							\
} grctx;								\
									\
static void grdestroy(grand *r)						\
  { grctx *g = (grctx *)r; BURN(*g); S_DESTROY(g); }			\
									\
static int grmisc(grand *r, unsigned op, ...)				\
{									\
  grctx *g = (grctx *)r;						\
  va_list ap;								\
  int rc = 0;								\
  uint32 i;								\
  octet buf[PRE##_BLKSZ];						\
  va_start(ap, op);							\
									\
  switch (op) {								\
    case GRAND_CHECK:							\
      switch (va_arg(ap, unsigned)) {					\
	case GRAND_CHECK:						\
	case GRAND_SEEDINT:						\
	case GRAND_SEEDUINT32:						\
	case GRAND_SEEDBLOCK:						\
	case GRAND_SEEDRAND:						\
	  rc = 1;							\
	  break;							\
	default:							\
	  rc = 0;							\
	  break;							\
      }									\
      break;								\
    case GRAND_SEEDINT:							\
      memset(buf, 0, sizeof(buf));					\
      i = va_arg(ap, unsigned);						\
      STORE32(buf, i);							\
      pre##_ofbsetiv(&g->k, buf);					\
      break;								\
    case GRAND_SEEDUINT32:						\
      memset(buf, 0, sizeof(buf));					\
      i = va_arg(ap, uint32);						\
      STORE32(buf, i);							\
      pre##_ofbsetiv(&g->k, buf);					\
      break;								\
    case GRAND_SEEDBLOCK: {						\
      const void *p = va_arg(ap, const void *);				\
      size_t sz = va_arg(ap, size_t);					\
      if (sz < sizeof(buf)) {						\
	memset(buf, 0, sizeof(buf));					\
	memcpy(buf, p, sz);						\
	p = buf;							\
      }									\
      pre##_ofbsetiv(&g->k, p);						\
    } break;								\
    case GRAND_SEEDRAND: {						\
      grand *rr = va_arg(ap, grand *);					\
      rr->ops->fill(rr, buf, sizeof(buf));				\
      pre##_ofbsetiv(&g->k, buf);					\
    } break;								\
    default:								\
      GRAND_BADOP;							\
      break;								\
  }									\
									\
  va_end(ap);								\
  return (rc);								\
}									\
									\
static octet grbyte(grand *r)						\
{									\
  grctx *g = (grctx *)r;						\
  octet o;								\
  pre##_ofbencrypt(&g->k, 0, &o, 1);					\
  return (o);								\
}									\
									\
static uint32 grword(grand *r)						\
{									\
  grctx *g = (grctx *)r;						\
  octet b[4];								\
  pre##_ofbencrypt(&g->k, 0, b, sizeof(b));				\
  return (LOAD32(b));							\
}									\
									\
static void grfill(grand *r, void *p, size_t sz)			\
  { grctx *g = (grctx *)r; pre##_ofbencrypt(&g->k, 0, p, sz); }		\
									\
static const grand_ops grops = {					\
  name "-ofb",								\
  GRAND_CRYPTO, 0,							\
  grmisc, grdestroy,							\
  grword, grbyte, grword, grand_defaultrange, grfill			\
};									\
									\
/* --- @pre_ofbrand@ --- *						\
 *									\
 * Arguments:	@const void *k@ = pointer to key material		\
 *		@size_t sz@ = size of key material			\
 *									\
 * Returns:	Pointer to generic random number generator interface.	\
 *									\
 * Use:		Creates a random number interface wrapper around an	\
 *		OFB-mode block cipher.					\
 */									\
									\
grand *pre##_ofbrand(const void *k, size_t sz)				\
{									\
  grctx *g = S_CREATE(grctx);						\
  g->r.ops = &grops;							\
  pre##_ofbinit(&g->k, k, sz, 0);					\
  return (&g->r);							\
}									\
									\
OFB_TESTX(PRE, pre, name, name)

/*----- Test rig ----------------------------------------------------------*/

#define OFB_TEST(PRE, pre) OFB_TESTX(PRE, pre, #pre, #pre)

#ifdef TEST_RIG

#include "modes-test.h"

/* --- @OFB_TEST@ --- *
 *
 * Arguments:	@PRE@, @pre@ = prefixes for block cipher definitions
 *
 * Use:		Standard test rig for OFB functions.
 */

#define OFB_TESTX(PRE, pre, name, fname)				\
									\
static pre##_ctx key;							\
static pre##_ofbctx ctx;						\
									\
static void pre##_ofb_test_setup(const octet *k, size_t ksz)		\
  { pre##_init(&key, k, ksz); pre##_ofbsetkey(&ctx, &key); }		\
									\
static void pre##_ofb_test_reset(const octet *iv)			\
  { pre##_ofbsetiv(&ctx, iv); }						\
									\
static void pre##_ofb_test_enc(const octet *s, octet *d, size_t sz)	\
  { pre##_ofbencrypt(&ctx, s, d, sz); }					\
									\
int main(int argc, char *argv[])					\
{									\
  return test_encmode(fname "-ofb", PRE##_KEYSZ, PRE##_BLKSZ, 1, 0,	\
		      pre##_ofb_test_setup, pre##_ofb_test_reset,	\
		      pre##_ofb_test_enc, pre##_ofb_test_enc,		\
		      argc, argv);					\
}

#else
#  define OFB_TESTX(PRE, pre, name, fname)
#endif

/*----- That's all, folks -------------------------------------------------*/

#ifdef __cplusplus
  }
#endif

#endif
Commit	Line	Data
79ba130c	1	/* --c--
79ba130c	2	*
79ba130c	3	* Definitions for output feedback mode
	4	*
	5	* (c) 1999 Straylight/Edgeware
	6	*/
	7
45c0fd36	8	/----- Licensing notice --------------------------------------------------
79ba130c	9	*
	10	* This file is part of Catacomb.
	11	*
	12	* Catacomb is free software; you can redistribute it and/or modify
	13	* it under the terms of the GNU Library General Public License as
	14	* published by the Free Software Foundation; either version 2 of the
	15	* License, or (at your option) any later version.
45c0fd36	16	*
79ba130c	17	* Catacomb is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	20	* GNU Library General Public License for more details.
45c0fd36	21	*
79ba130c	22	* You should have received a copy of the GNU Library General Public
	23	* License along with Catacomb; if not, write to the Free
	24	* Software Foundation, Inc., 59 Temple Place - Suite 330, Boston,
	25	* MA 02111-1307, USA.
	26	*/
	27
79ba130c	28	#ifndef CATACOMB_OFB_DEF_H
	29	#define CATACOMB_OFB_DEF_H
	30
	31	#ifdef __cplusplus
	32	extern "C" {
	33	#endif
	34
	35	/----- Header files ------------------------------------------------------/
	36
	37	#include <stdarg.h>
	38	#include <string.h>
	39
	40	#include <mLib/bits.h>
	41	#include <mLib/sub.h>
	42
2af20fa2	43	#ifndef CATACOMB_ARENA_H
	44	# include "arena.h"
	45	#endif
	46
79ba130c	47	#ifndef CATACOMB_BLKC_H
	48	# include "blkc.h"
	49	#endif
	50
	51	#ifndef CATACOMB_GCIPHER_H
	52	# include "gcipher.h"
	53	#endif
	54
	55	#ifndef CATACOMB_PARANOIA_H
	56	# include "paranoia.h"
	57	#endif
	58
	59	/----- Macros ------------------------------------------------------------/
	60
	61	/* --- @OFB_DEF@ --- *
	62	*
	63	* Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
	64	*
	65	* Use: Creates definitions for output feedback mode.
	66	*/
	67
aaae9cab MW	68	#define OFB_DEF(PRE, pre) OFB_DEFX(PRE, pre, #pre, #pre)
	69
	70	#define OFB_DEFX(PRE, pre, name, fname) \
79ba130c	71	\
	72	/* --- @pre_ofbgetiv@ --- * \
	73	* \
	74	* Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \
4efe32ba	75	* @void *iv@ = pointer to output data block \
79ba130c	76	* \
	77	* Returns: --- \
	78	* \
	79	* Use: Reads the currently set IV. Reading and setting an IV \
	80	* is not transparent to the cipher. It will add a `step' \
	81	* which must be matched by a similar operation during \
	82	* decryption. \
	83	*/ \
	84	\
	85	void pre##_ofbgetiv(const pre##_ofbctx ctx, void iv) \
	86	{ \
	87	octet *p = iv; \
2af20fa2	88	unsigned off = ctx->off; \
2af20fa2	89	unsigned rest = PRE##_BLKSZ - off; \
0fee61eb MW	90	\
	91	memcpy(p, ctx->b + off, rest); \
	92	memcpy(p + rest, ctx->b, off); \
79ba130c	93	} \
	94	\
	95	/* --- @pre_ofbsetiv@ --- * \
	96	* \
	97	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	98	* @cnost void *iv@ = pointer to IV to set \
	99	* \
	100	* Returns: --- \
	101	* \
	102	* Use: Sets the IV to use for subsequent encryption. \
	103	*/ \
	104	\
	105	void pre##_ofbsetiv(pre##_ofbctx ctx, const void iv) \
0fee61eb	106	{ memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = PRE##_BLKSZ; } \
79ba130c	107	\
	108	/* --- @pre_ofbbdry@ --- * \
	109	* \
	110	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	111	* \
	112	* Returns: --- \
	113	* \
	114	* Use: Inserts a boundary during encryption. Successful \
	115	* decryption must place a similar boundary. \
	116	*/ \
	117	\
	118	void pre##_ofbbdry(pre##_ofbctx *ctx) \
	119	{ \
0fee61eb MW	120	uint32 t[PRE##_BLKSZ/4]; \
	121	\
	122	BLKC_LOAD(PRE, t, ctx->b); \
	123	pre##_eblk(&ctx->ctx, t, t); \
	124	BLKC_STORE(PRE, ctx->b, t); \
2af20fa2	125	ctx->off = PRE##_BLKSZ; \
0fee61eb	126	BURN(t); \
79ba130c	127	} \
	128	\
	129	/* --- @pre_ofbsetkey@ --- * \
	130	* \
	131	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	132	* @const pre_ctx *k@ = pointer to cipher context \
	133	* \
	134	* Returns: --- \
	135	* \
	136	* Use: Sets the OFB context to use a different cipher key. \
	137	*/ \
	138	\
	139	void pre##_ofbsetkey(pre##_ofbctx ctx, const pre##_ctx k) \
0fee61eb	140	{ ctx->ctx = *k; } \
79ba130c	141	\
	142	/* --- @pre_ofbinit@ --- * \
	143	* \
	144	* Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \
	145	* @const void *key@ = pointer to the key buffer \
	146	* @size_t sz@ = size of the key \
	147	* @const void *iv@ = pointer to initialization vector \
	148	* \
	149	* Returns: --- \
	150	* \
	151	* Use: Initializes a OFB context ready for use. You should \
	152	* ensure that the IV chosen is unique: reusing an IV will \
	153	* compromise the security of the entire plaintext. This \
	154	* is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \
	155	* and @pre_ofbsetiv@. \
	156	*/ \
	157	\
	158	void pre##_ofbinit(pre##_ofbctx *ctx, \
	159	const void *key, size_t sz, \
	160	const void *iv) \
	161	{ \
4e66da02	162	static const octet zero[PRE##_BLKSZ] = { 0 }; \
0fee61eb	163	\
79ba130c	164	pre##_init(&ctx->ctx, key, sz); \
	165	pre##_ofbsetiv(ctx, iv ? iv : zero); \
	166	} \
	167	\
	168	/* --- @pre_ofbencrypt@ --- * \
	169	* \
	170	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	171	* @const void *src@ = pointer to source data \
	172	* @void *dest@ = pointer to destination data \
	173	* @size_t sz@ = size of block to be encrypted \
	174	* \
	175	* Returns: --- \
	176	* \
	177	* Use: Encrypts or decrypts a block with a block cipher in OFB \
	178	* mode: encryption and decryption are the same in OFB. \
	179	* The destination may be null to just churn the feedback \
	180	* round for a bit. The source may be null to use the \
	181	* cipher as a random data generator. \
	182	*/ \
	183	\
	184	void pre##_ofbencrypt(pre##_ofbctx *ctx, \
81b52866 MW	185	const void src, void dest, \
81b52866 MW	186	size_t sz) \
79ba130c	187	{ \
	188	const octet *s = src; \
	189	octet *d = dest; \
2af20fa2	190	unsigned off = ctx->off; \
0fee61eb MW	191	uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4]; \
0fee61eb MW	192	octet y; \
79ba130c	193	\
	194	/* --- Empty blocks are trivial --- */ \
	195	\
0fee61eb	196	if (!sz) return; \
79ba130c	197	\
	198	/* --- If I can deal with the block from my buffer, do that --- */ \
	199	\
0fee61eb	200	if (sz < PRE##_BLKSZ - off) goto small; \
79ba130c	201	\
	202	/* --- Finish off what's left in my buffer --- */ \
	203	\
0fee61eb MW	204	if (!d) sz -= PRE##_BLKSZ - off; \
	205	else while (off < PRE##_BLKSZ) \
	206	{ y = s ? s++ : 0; d++ = ctx->b[off++] ^ y; sz--; } \
79ba130c	207	\
	208	/* --- Main encryption loop --- */ \
	209	\
0fee61eb	210	BLKC_LOAD(PRE, t, ctx->b); \
79ba130c	211	\
0fee61eb MW	212	for (;;) { \
	213	pre##_eblk(&ctx->ctx, t, t); \
	214	if (sz < PRE##_BLKSZ) break; \
	215	if (!d) /* do nothing */; \
	216	else if (!s) { BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; } \
	217	else { \
	218	BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ; \
	219	BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ; \
	220	} \
	221	sz -= PRE##_BLKSZ; \
79ba130c	222	} \
79ba130c	223	\
0fee61eb MW	224	BLKC_STORE(PRE, ctx->b, t); \
	225	off = 0; \
	226	\
79ba130c	227	/* --- Tidying up the tail end --- */ \
	228	\
	229	if (sz) { \
	230	small: \
0fee61eb MW	231	if (!d) off += sz; \
	232	else do { y = s ? s++ : 0; d++ = ctx->b[off++] ^ y; sz--; } \
	233	while (sz); \
79ba130c	234	} \
	235	\
	236	/* --- Done --- */ \
	237	\
	238	ctx->off = off; \
	239	return; \
	240	} \
	241	\
	242	/* --- Generic cipher interface --- */ \
	243	\
	244	static const gcipher_ops gops; \
	245	\
	246	typedef struct gctx { \
	247	gcipher c; \
	248	pre##_ofbctx k; \
	249	} gctx; \
	250	\
	251	static gcipher ginit(const void k, size_t sz) \
	252	{ \
2af20fa2	253	gctx *g = S_CREATE(gctx); \
79ba130c	254	g->c.ops = &gops; \
	255	pre##_ofbinit(&g->k, k, sz, 0); \
	256	return (&g->c); \
	257	} \
	258	\
	259	static void gencrypt(gcipher c, const void s, void *t, size_t sz) \
0fee61eb	260	{ gctx g = (gctx )c; pre##_ofbencrypt(&g->k, s, t, sz); } \
79ba130c	261	\
79ba130c	262	static void gdestroy(gcipher *c) \
0fee61eb	263	{ gctx g = (gctx )c; BURN(*g); S_DESTROY(g); } \
79ba130c	264	\
79ba130c	265	static void gsetiv(gcipher c, const void iv) \
0fee61eb	266	{ gctx g = (gctx )c; pre##_ofbsetiv(&g->k, iv); } \
79ba130c	267	\
	268	static void gbdry(gcipher *c) \
	269	{ \
	270	gctx g = (gctx )c; \
	271	pre##_ofbbdry(&g->k); \
	272	} \
	273	\
	274	static const gcipher_ops gops = { \
2af20fa2	275	&pre##_ofb, \
79ba130c	276	gencrypt, gencrypt, gdestroy, gsetiv, gbdry \
	277	}; \
	278	\
	279	const gccipher pre##_ofb = { \
aaae9cab	280	name "-ofb", pre##_keysz, PRE##_BLKSZ, \
79ba130c	281	ginit \
	282	}; \
	283	\
	284	/* --- Generic random number generator interface --- */ \
	285	\
	286	typedef struct grctx { \
	287	grand r; \
	288	pre##_ofbctx k; \
	289	} grctx; \
	290	\
	291	static void grdestroy(grand *r) \
0fee61eb	292	{ grctx g = (grctx )r; BURN(*g); S_DESTROY(g); } \
79ba130c	293	\
	294	static int grmisc(grand *r, unsigned op, ...) \
	295	{ \
	296	grctx g = (grctx )r; \
	297	va_list ap; \
	298	int rc = 0; \
360c232e	299	uint32 i; \
79ba130c	300	octet buf[PRE##_BLKSZ]; \
	301	va_start(ap, op); \
	302	\
	303	switch (op) { \
	304	case GRAND_CHECK: \
	305	switch (va_arg(ap, unsigned)) { \
	306	case GRAND_CHECK: \
	307	case GRAND_SEEDINT: \
	308	case GRAND_SEEDUINT32: \
	309	case GRAND_SEEDBLOCK: \
4ab1268f	310	case GRAND_SEEDRAND: \
79ba130c	311	rc = 1; \
	312	break; \
	313	default: \
	314	rc = 0; \
	315	break; \
	316	} \
	317	break; \
	318	case GRAND_SEEDINT: \
	319	memset(buf, 0, sizeof(buf)); \
360c232e	320	i = va_arg(ap, unsigned); \
360c232e	321	STORE32(buf, i); \
79ba130c	322	pre##_ofbsetiv(&g->k, buf); \
	323	break; \
	324	case GRAND_SEEDUINT32: \
	325	memset(buf, 0, sizeof(buf)); \
360c232e	326	i = va_arg(ap, uint32); \
360c232e	327	STORE32(buf, i); \
79ba130c	328	pre##_ofbsetiv(&g->k, buf); \
	329	break; \
	330	case GRAND_SEEDBLOCK: { \
	331	const void p = va_arg(ap, const void ); \
	332	size_t sz = va_arg(ap, size_t); \
	333	if (sz < sizeof(buf)) { \
	334	memset(buf, 0, sizeof(buf)); \
	335	memcpy(buf, p, sz); \
	336	p = buf; \
	337	} \
	338	pre##_ofbsetiv(&g->k, p); \
	339	} break; \
4ab1268f	340	case GRAND_SEEDRAND: { \
	341	grand rr = va_arg(ap, grand ); \
	342	rr->ops->fill(rr, buf, sizeof(buf)); \
	343	pre##_ofbsetiv(&g->k, buf); \
	344	} break; \
	345	default: \
	346	GRAND_BADOP; \
	347	break; \
79ba130c	348	} \
	349	\
	350	va_end(ap); \
	351	return (rc); \
	352	} \
	353	\
	354	static octet grbyte(grand *r) \
	355	{ \
	356	grctx g = (grctx )r; \
	357	octet o; \
	358	pre##_ofbencrypt(&g->k, 0, &o, 1); \
	359	return (o); \
	360	} \
	361	\
	362	static uint32 grword(grand *r) \
	363	{ \
	364	grctx g = (grctx )r; \
	365	octet b[4]; \
	366	pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \
	367	return (LOAD32(b)); \
	368	} \
	369	\
	370	static void grfill(grand r, void p, size_t sz) \
0fee61eb	371	{ grctx g = (grctx )r; pre##_ofbencrypt(&g->k, 0, p, sz); } \
79ba130c	372	\
79ba130c	373	static const grand_ops grops = { \
aaae9cab	374	name "-ofb", \
2af20fa2	375	GRAND_CRYPTO, 0, \
79ba130c	376	grmisc, grdestroy, \
44ff6c11	377	grword, grbyte, grword, grand_defaultrange, grfill \
79ba130c	378	}; \
	379	\
	380	/* --- @pre_ofbrand@ --- * \
	381	* \
	382	* Arguments: @const void *k@ = pointer to key material \
	383	* @size_t sz@ = size of key material \
	384	* \
	385	* Returns: Pointer to generic random number generator interface. \
	386	* \
	387	* Use: Creates a random number interface wrapper around an \
	388	* OFB-mode block cipher. \
	389	*/ \
	390	\
	391	grand pre##_ofbrand(const void k, size_t sz) \
	392	{ \
2af20fa2	393	grctx *g = S_CREATE(grctx); \
79ba130c	394	g->r.ops = &grops; \
	395	pre##_ofbinit(&g->k, k, sz, 0); \
	396	return (&g->r); \
	397	} \
	398	\
aaae9cab	399	OFB_TESTX(PRE, pre, name, name)
79ba130c	400
	401	/----- Test rig ----------------------------------------------------------/
	402
aaae9cab MW	403	#define OFB_TEST(PRE, pre) OFB_TESTX(PRE, pre, #pre, #pre)
aaae9cab MW	404
79ba130c	405	#ifdef TEST_RIG
79ba130c	406
57f459eb	407	#include "modes-test.h"
79ba130c	408
	409	/* --- @OFB_TEST@ --- *
	410	*
	411	* Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
	412	*
	413	* Use: Standard test rig for OFB functions.
	414	*/
	415
81b52866	416	#define OFB_TESTX(PRE, pre, name, fname) \
79ba130c	417	\
57f459eb MW	418	static pre##_ctx key; \
57f459eb MW	419	static pre##_ofbctx ctx; \
79ba130c	420	\
57f459eb MW	421	static void pre##_ofb_test_setup(const octet *k, size_t ksz) \
57f459eb MW	422	{ pre##_init(&key, k, ksz); pre##_ofbsetkey(&ctx, &key); } \
79ba130c	423	\
57f459eb MW	424	static void pre##_ofb_test_reset(const octet *iv) \
57f459eb MW	425	{ pre##_ofbsetiv(&ctx, iv); } \
79ba130c	426	\
57f459eb MW	427	static void pre##_ofb_test_enc(const octet s, octet d, size_t sz) \
57f459eb MW	428	{ pre##_ofbencrypt(&ctx, s, d, sz); } \
79ba130c	429	\
57f459eb	430	int main(int argc, char *argv[]) \
79ba130c	431	{ \
57f459eb MW	432	return test_encmode(fname "-ofb", PRE##_KEYSZ, PRE##_BLKSZ, 1, 0, \
	433	pre##_ofb_test_setup, pre##_ofb_test_reset, \
	434	pre##_ofb_test_enc, pre##_ofb_test_enc, \
	435	argc, argv); \
79ba130c	436	}
	437
	438	#else
aaae9cab	439	# define OFB_TESTX(PRE, pre, name, fname)
79ba130c	440	#endif
	441
	442	/----- That's all, folks -------------------------------------------------/
	443
	444	#ifdef __cplusplus
	445	}
	446	#endif
	447
	448	#endif