[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

#ifndef CATACOMB_RSVR_H
#  include "rsvr.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 = 0; }			\
									\
/* --- @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 = 0;								\
  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.			\
 */									\
									\
static const rsvr_policy pre##_ofbpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
									\
void pre##_ofbencrypt(pre##_ofbctx *ctx,				\
		      const void *src, void *dest,			\
		      size_t sz)					\
{									\
  rsvr_plan plan;							\
  const octet *s = src, *p;						\
  octet *d = dest;							\
  uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4];				\
									\
  /* Construct a plan and prepare to follow through. */			\
  rsvr_mkplan(&plan, &pre##_ofbpolicy, ctx->off, sz);			\
  BLKC_LOAD(PRE, t, ctx->b);						\
									\
  /* Initial portion, fulfilled from the buffer.  If the chunk is small	\
   * enough, then this will be the only portion.  If the buffer is	\
   * currently empty, then we must prepare it.				\
   */									\
  if (plan.head) {							\
    if (!ctx->off) {							\
      pre##_eblk(&ctx->ctx, t, t);					\
      BLKC_STORE(PRE, ctx->b, t);					\
    }									\
    p = ctx->b + ctx->off; ctx->off += plan.head;			\
    if (!d) /* nothing to do */;					\
    else if (!s) { memcpy(d, p, plan.head); d += plan.head; }		\
    else while (plan.head--) *d++ = *s++ ^ *p++;			\
  }									\
									\
  /* If the buffer is all used, then reset it ready for next time. */	\
  ctx->off -= plan.from_rsvr;						\
									\
  /* Handle multiple whole blocks. */					\
  if (!d) while (plan.from_input) {					\
    pre##_eblk(&ctx->ctx, t, t);					\
    plan.from_input -= PRE##_BLKSZ;					\
  } else if (!s) while (plan.from_input) {				\
    pre##_eblk(&ctx->ctx, t, t);					\
    BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ;				\
    plan.from_input -= PRE##_BLKSZ;					\
  } else while (plan.from_input) {					\
    pre##_eblk(&ctx->ctx, t, t);					\
    BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ;				\
    BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ;			\
    plan.from_input -= PRE##_BLKSZ;					\
  }									\
									\
  /* Final portion.  Note that the buffer must be empty if there is a	\
   * tail, since otherwise the input data would have been part of the	\
   * head portion instad. */						\
  if (!plan.tail)							\
    BLKC_STORE(PRE, ctx->b, t);						\
  else {								\
    pre##_eblk(&ctx->ctx, t, t);					\
    BLKC_STORE(PRE, ctx->b, t);						\
    p = ctx->b; ctx->off += plan.tail;					\
    if (!d) /* nothing to do */;					\
    else if (!s) { memcpy(d, p, plan.tail); d += plan.tail; }		\
    else while (plan.tail--) *d++ = *s++ ^ *p++;			\
  }									\
}									\
									\
/* --- 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
6a0eb244 MW	59	#ifndef CATACOMB_RSVR_H
	60	# include "rsvr.h"
	61	#endif
	62
79ba130c	63	/----- Macros ------------------------------------------------------------/
	64
	65	/* --- @OFB_DEF@ --- *
	66	*
	67	* Arguments: @PRE@, @pre@ = prefixes for the underlying block cipher
	68	*
	69	* Use: Creates definitions for output feedback mode.
	70	*/
	71
aaae9cab MW	72	#define OFB_DEF(PRE, pre) OFB_DEFX(PRE, pre, #pre, #pre)
	73
	74	#define OFB_DEFX(PRE, pre, name, fname) \
79ba130c	75	\
	76	/* --- @pre_ofbgetiv@ --- * \
	77	* \
	78	* Arguments: @const pre_ofbctx *ctx@ = pointer to OFB context block \
4efe32ba	79	* @void *iv@ = pointer to output data block \
79ba130c	80	* \
	81	* Returns: --- \
	82	* \
	83	* Use: Reads the currently set IV. Reading and setting an IV \
	84	* is not transparent to the cipher. It will add a `step' \
	85	* which must be matched by a similar operation during \
	86	* decryption. \
	87	*/ \
	88	\
	89	void pre##_ofbgetiv(const pre##_ofbctx ctx, void iv) \
	90	{ \
	91	octet *p = iv; \
2af20fa2	92	unsigned off = ctx->off; \
2af20fa2	93	unsigned rest = PRE##_BLKSZ - off; \
0fee61eb MW	94	\
	95	memcpy(p, ctx->b + off, rest); \
	96	memcpy(p + rest, ctx->b, off); \
79ba130c	97	} \
	98	\
	99	/* --- @pre_ofbsetiv@ --- * \
	100	* \
	101	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	102	* @cnost void *iv@ = pointer to IV to set \
	103	* \
	104	* Returns: --- \
	105	* \
	106	* Use: Sets the IV to use for subsequent encryption. \
	107	*/ \
	108	\
	109	void pre##_ofbsetiv(pre##_ofbctx ctx, const void iv) \
6a0eb244	110	{ memcpy(ctx->b, iv, PRE##_BLKSZ); ctx->off = 0; } \
79ba130c	111	\
	112	/* --- @pre_ofbbdry@ --- * \
	113	* \
	114	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	115	* \
	116	* Returns: --- \
	117	* \
	118	* Use: Inserts a boundary during encryption. Successful \
	119	* decryption must place a similar boundary. \
	120	*/ \
	121	\
	122	void pre##_ofbbdry(pre##_ofbctx *ctx) \
	123	{ \
0fee61eb MW	124	uint32 t[PRE##_BLKSZ/4]; \
	125	\
	126	BLKC_LOAD(PRE, t, ctx->b); \
	127	pre##_eblk(&ctx->ctx, t, t); \
	128	BLKC_STORE(PRE, ctx->b, t); \
6a0eb244	129	ctx->off = 0; \
0fee61eb	130	BURN(t); \
79ba130c	131	} \
	132	\
	133	/* --- @pre_ofbsetkey@ --- * \
	134	* \
	135	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	136	* @const pre_ctx *k@ = pointer to cipher context \
	137	* \
	138	* Returns: --- \
	139	* \
	140	* Use: Sets the OFB context to use a different cipher key. \
	141	*/ \
	142	\
	143	void pre##_ofbsetkey(pre##_ofbctx ctx, const pre##_ctx k) \
0fee61eb	144	{ ctx->ctx = *k; } \
79ba130c	145	\
	146	/* --- @pre_ofbinit@ --- * \
	147	* \
	148	* Arguments: @pre_ofbctx *ctx@ = pointer to cipher context \
	149	* @const void *key@ = pointer to the key buffer \
	150	* @size_t sz@ = size of the key \
	151	* @const void *iv@ = pointer to initialization vector \
	152	* \
	153	* Returns: --- \
	154	* \
	155	* Use: Initializes a OFB context ready for use. You should \
	156	* ensure that the IV chosen is unique: reusing an IV will \
	157	* compromise the security of the entire plaintext. This \
	158	* is equivalent to calls to @pre_init@, @pre_ofbsetkey@ \
	159	* and @pre_ofbsetiv@. \
	160	*/ \
	161	\
	162	void pre##_ofbinit(pre##_ofbctx *ctx, \
	163	const void *key, size_t sz, \
	164	const void *iv) \
	165	{ \
4e66da02	166	static const octet zero[PRE##_BLKSZ] = { 0 }; \
0fee61eb	167	\
79ba130c	168	pre##_init(&ctx->ctx, key, sz); \
	169	pre##_ofbsetiv(ctx, iv ? iv : zero); \
	170	} \
	171	\
	172	/* --- @pre_ofbencrypt@ --- * \
	173	* \
	174	* Arguments: @pre_ofbctx *ctx@ = pointer to OFB context block \
	175	* @const void *src@ = pointer to source data \
	176	* @void *dest@ = pointer to destination data \
	177	* @size_t sz@ = size of block to be encrypted \
	178	* \
	179	* Returns: --- \
	180	* \
	181	* Use: Encrypts or decrypts a block with a block cipher in OFB \
	182	* mode: encryption and decryption are the same in OFB. \
	183	* The destination may be null to just churn the feedback \
	184	* round for a bit. The source may be null to use the \
	185	* cipher as a random data generator. \
	186	*/ \
	187	\
6a0eb244 MW	188	static const rsvr_policy pre##_ofbpolicy = { 0, PRE##_BLKSZ, PRE##_BLKSZ }; \
6a0eb244 MW	189	\
79ba130c	190	void pre##_ofbencrypt(pre##_ofbctx *ctx, \
81b52866 MW	191	const void src, void dest, \
81b52866 MW	192	size_t sz) \
79ba130c	193	{ \
6a0eb244 MW	194	rsvr_plan plan; \
6a0eb244 MW	195	const octet s = src, p; \
79ba130c	196	octet *d = dest; \
0fee61eb	197	uint32 t[PRE##_BLKSZ/4], u[PRE##_BLKSZ/4]; \
79ba130c	198	\
6a0eb244 MW	199	/* Construct a plan and prepare to follow through. */ \
6a0eb244 MW	200	rsvr_mkplan(&plan, &pre##_ofbpolicy, ctx->off, sz); \
0fee61eb	201	BLKC_LOAD(PRE, t, ctx->b); \
79ba130c	202	\
6a0eb244 MW	203	/* Initial portion, fulfilled from the buffer. If the chunk is small \
	204	* enough, then this will be the only portion. If the buffer is \
	205	* currently empty, then we must prepare it. \
	206	*/ \
	207	if (plan.head) { \
	208	if (!ctx->off) { \
	209	pre##_eblk(&ctx->ctx, t, t); \
	210	BLKC_STORE(PRE, ctx->b, t); \
0fee61eb	211	} \
6a0eb244 MW	212	p = ctx->b + ctx->off; ctx->off += plan.head; \
	213	if (!d) /* nothing to do */; \
	214	else if (!s) { memcpy(d, p, plan.head); d += plan.head; } \
	215	else while (plan.head--) d++ = s++ ^ *p++; \
79ba130c	216	} \
79ba130c	217	\
6a0eb244 MW	218	/* If the buffer is all used, then reset it ready for next time. */ \
6a0eb244 MW	219	ctx->off -= plan.from_rsvr; \
0fee61eb	220	\
6a0eb244 MW	221	/* Handle multiple whole blocks. */ \
	222	if (!d) while (plan.from_input) { \
	223	pre##_eblk(&ctx->ctx, t, t); \
	224	plan.from_input -= PRE##_BLKSZ; \
	225	} else if (!s) while (plan.from_input) { \
	226	pre##_eblk(&ctx->ctx, t, t); \
	227	BLKC_STORE(PRE, d, t); d += PRE##_BLKSZ; \
	228	plan.from_input -= PRE##_BLKSZ; \
	229	} else while (plan.from_input) { \
	230	pre##_eblk(&ctx->ctx, t, t); \
	231	BLKC_LOAD(PRE, u, s); s += PRE##_BLKSZ; \
	232	BLKC_XSTORE(PRE, d, t, u); d += PRE##_BLKSZ; \
	233	plan.from_input -= PRE##_BLKSZ; \
79ba130c	234	} \
79ba130c	235	\
6a0eb244 MW	236	/* Final portion. Note that the buffer must be empty if there is a \
	237	* tail, since otherwise the input data would have been part of the \
	238	* head portion instad. */ \
	239	if (!plan.tail) \
	240	BLKC_STORE(PRE, ctx->b, t); \
	241	else { \
	242	pre##_eblk(&ctx->ctx, t, t); \
	243	BLKC_STORE(PRE, ctx->b, t); \
	244	p = ctx->b; ctx->off += plan.tail; \
	245	if (!d) /* nothing to do */; \
	246	else if (!s) { memcpy(d, p, plan.tail); d += plan.tail; } \
	247	else while (plan.tail--) d++ = s++ ^ *p++; \
	248	} \
79ba130c	249	} \
	250	\
	251	/* --- Generic cipher interface --- */ \
	252	\
	253	static const gcipher_ops gops; \
	254	\
	255	typedef struct gctx { \
	256	gcipher c; \
	257	pre##_ofbctx k; \
	258	} gctx; \
	259	\
	260	static gcipher ginit(const void k, size_t sz) \
	261	{ \
2af20fa2	262	gctx *g = S_CREATE(gctx); \
79ba130c	263	g->c.ops = &gops; \
	264	pre##_ofbinit(&g->k, k, sz, 0); \
	265	return (&g->c); \
	266	} \
	267	\
	268	static void gencrypt(gcipher c, const void s, void *t, size_t sz) \
0fee61eb	269	{ gctx g = (gctx )c; pre##_ofbencrypt(&g->k, s, t, sz); } \
79ba130c	270	\
79ba130c	271	static void gdestroy(gcipher *c) \
0fee61eb	272	{ gctx g = (gctx )c; BURN(*g); S_DESTROY(g); } \
79ba130c	273	\
79ba130c	274	static void gsetiv(gcipher c, const void iv) \
0fee61eb	275	{ gctx g = (gctx )c; pre##_ofbsetiv(&g->k, iv); } \
79ba130c	276	\
	277	static void gbdry(gcipher *c) \
	278	{ \
	279	gctx g = (gctx )c; \
	280	pre##_ofbbdry(&g->k); \
	281	} \
	282	\
	283	static const gcipher_ops gops = { \
2af20fa2	284	&pre##_ofb, \
79ba130c	285	gencrypt, gencrypt, gdestroy, gsetiv, gbdry \
	286	}; \
	287	\
	288	const gccipher pre##_ofb = { \
aaae9cab	289	name "-ofb", pre##_keysz, PRE##_BLKSZ, \
79ba130c	290	ginit \
	291	}; \
	292	\
	293	/* --- Generic random number generator interface --- */ \
	294	\
	295	typedef struct grctx { \
	296	grand r; \
	297	pre##_ofbctx k; \
	298	} grctx; \
	299	\
	300	static void grdestroy(grand *r) \
0fee61eb	301	{ grctx g = (grctx )r; BURN(*g); S_DESTROY(g); } \
79ba130c	302	\
	303	static int grmisc(grand *r, unsigned op, ...) \
	304	{ \
	305	grctx g = (grctx )r; \
	306	va_list ap; \
	307	int rc = 0; \
360c232e	308	uint32 i; \
79ba130c	309	octet buf[PRE##_BLKSZ]; \
	310	va_start(ap, op); \
	311	\
	312	switch (op) { \
	313	case GRAND_CHECK: \
	314	switch (va_arg(ap, unsigned)) { \
	315	case GRAND_CHECK: \
	316	case GRAND_SEEDINT: \
	317	case GRAND_SEEDUINT32: \
	318	case GRAND_SEEDBLOCK: \
4ab1268f	319	case GRAND_SEEDRAND: \
79ba130c	320	rc = 1; \
	321	break; \
	322	default: \
	323	rc = 0; \
	324	break; \
	325	} \
	326	break; \
	327	case GRAND_SEEDINT: \
	328	memset(buf, 0, sizeof(buf)); \
360c232e	329	i = va_arg(ap, unsigned); \
360c232e	330	STORE32(buf, i); \
79ba130c	331	pre##_ofbsetiv(&g->k, buf); \
	332	break; \
	333	case GRAND_SEEDUINT32: \
	334	memset(buf, 0, sizeof(buf)); \
360c232e	335	i = va_arg(ap, uint32); \
360c232e	336	STORE32(buf, i); \
79ba130c	337	pre##_ofbsetiv(&g->k, buf); \
	338	break; \
	339	case GRAND_SEEDBLOCK: { \
	340	const void p = va_arg(ap, const void ); \
	341	size_t sz = va_arg(ap, size_t); \
	342	if (sz < sizeof(buf)) { \
	343	memset(buf, 0, sizeof(buf)); \
	344	memcpy(buf, p, sz); \
	345	p = buf; \
	346	} \
	347	pre##_ofbsetiv(&g->k, p); \
	348	} break; \
4ab1268f	349	case GRAND_SEEDRAND: { \
	350	grand rr = va_arg(ap, grand ); \
	351	rr->ops->fill(rr, buf, sizeof(buf)); \
	352	pre##_ofbsetiv(&g->k, buf); \
	353	} break; \
	354	default: \
	355	GRAND_BADOP; \
	356	break; \
79ba130c	357	} \
	358	\
	359	va_end(ap); \
	360	return (rc); \
	361	} \
	362	\
	363	static octet grbyte(grand *r) \
	364	{ \
	365	grctx g = (grctx )r; \
	366	octet o; \
	367	pre##_ofbencrypt(&g->k, 0, &o, 1); \
	368	return (o); \
	369	} \
	370	\
	371	static uint32 grword(grand *r) \
	372	{ \
	373	grctx g = (grctx )r; \
	374	octet b[4]; \
	375	pre##_ofbencrypt(&g->k, 0, b, sizeof(b)); \
	376	return (LOAD32(b)); \
	377	} \
	378	\
	379	static void grfill(grand r, void p, size_t sz) \
0fee61eb	380	{ grctx g = (grctx )r; pre##_ofbencrypt(&g->k, 0, p, sz); } \
79ba130c	381	\
79ba130c	382	static const grand_ops grops = { \
aaae9cab	383	name "-ofb", \
2af20fa2	384	GRAND_CRYPTO, 0, \
79ba130c	385	grmisc, grdestroy, \
44ff6c11	386	grword, grbyte, grword, grand_defaultrange, grfill \
79ba130c	387	}; \
	388	\
	389	/* --- @pre_ofbrand@ --- * \
	390	* \
	391	* Arguments: @const void *k@ = pointer to key material \
	392	* @size_t sz@ = size of key material \
	393	* \
	394	* Returns: Pointer to generic random number generator interface. \
	395	* \
	396	* Use: Creates a random number interface wrapper around an \
	397	* OFB-mode block cipher. \
	398	*/ \
	399	\
	400	grand pre##_ofbrand(const void k, size_t sz) \
	401	{ \
2af20fa2	402	grctx *g = S_CREATE(grctx); \
79ba130c	403	g->r.ops = &grops; \
	404	pre##_ofbinit(&g->k, k, sz, 0); \
	405	return (&g->r); \
	406	} \
	407	\
aaae9cab	408	OFB_TESTX(PRE, pre, name, name)
79ba130c	409
	410	/----- Test rig ----------------------------------------------------------/
	411
aaae9cab MW	412	#define OFB_TEST(PRE, pre) OFB_TESTX(PRE, pre, #pre, #pre)
aaae9cab MW	413
79ba130c	414	#ifdef TEST_RIG
79ba130c	415
57f459eb	416	#include "modes-test.h"
79ba130c	417
	418	/* --- @OFB_TEST@ --- *
	419	*
	420	* Arguments: @PRE@, @pre@ = prefixes for block cipher definitions
	421	*
	422	* Use: Standard test rig for OFB functions.
	423	*/
	424
81b52866	425	#define OFB_TESTX(PRE, pre, name, fname) \
79ba130c	426	\
57f459eb MW	427	static pre##_ctx key; \
57f459eb MW	428	static pre##_ofbctx ctx; \
79ba130c	429	\
57f459eb MW	430	static void pre##_ofb_test_setup(const octet *k, size_t ksz) \
57f459eb MW	431	{ pre##_init(&key, k, ksz); pre##_ofbsetkey(&ctx, &key); } \
79ba130c	432	\
57f459eb MW	433	static void pre##_ofb_test_reset(const octet *iv) \
57f459eb MW	434	{ pre##_ofbsetiv(&ctx, iv); } \
79ba130c	435	\
57f459eb MW	436	static void pre##_ofb_test_enc(const octet s, octet d, size_t sz) \
57f459eb MW	437	{ pre##_ofbencrypt(&ctx, s, d, sz); } \
79ba130c	438	\
57f459eb	439	int main(int argc, char *argv[]) \
79ba130c	440	{ \
57f459eb MW	441	return test_encmode(fname "-ofb", PRE##_KEYSZ, PRE##_BLKSZ, 1, 0, \
	442	pre##_ofb_test_setup, pre##_ofb_test_reset, \
	443	pre##_ofb_test_enc, pre##_ofb_test_enc, \
	444	argc, argv); \
79ba130c	445	}
	446
	447	#else
aaae9cab	448	# define OFB_TESTX(PRE, pre, name, fname)
79ba130c	449	#endif
	450
	451	/----- That's all, folks -------------------------------------------------/
	452
	453	#ifdef __cplusplus
	454	}
	455	#endif
	456
	457	#endif