crypto: hash - Added scatter list walking helper

This patch adds the walking helpers for hash algorithms akin to those of block ciphers. This is a necessary step before we can reimplement existing hash algorithms using the new ahash interface. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

crypto: hash - Added scatter list walking helper
This patch adds the walking helpers for hash algorithms akin to those of block ciphers. This is a necessary step before we can reimplement existing hash algorithms using the new ahash interface. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Herbert Xu
1 parent b8454eebe3
Showing 2 changed files with 131 additions and 1 deletions Side-by-side Diff
crypto/ahash.c
include/crypto/internal/hash.h
@@ -13,7 +13,8 @@
  *
  */
  
-#include <crypto/algapi.h>
+#include <crypto/internal/hash.h>
+#include <crypto/scatterwalk.h>
 #include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
@@ -22,6 +23,94 @@
 #include <linux/seq_file.h>
  
 #include "internal.h"
+
+static int hash_walk_next(struct crypto_hash_walk *walk)
+{
+	unsigned int alignmask = walk->alignmask;
+	unsigned int offset = walk->offset;
+	unsigned int nbytes = min(walk->entrylen,
+				  ((unsigned int)(PAGE_SIZE)) - offset);
+
+	walk->data = crypto_kmap(walk->pg, 0);
+	walk->data += offset;
+
+	if (offset & alignmask)
+		nbytes = alignmask + 1 - (offset & alignmask);
+
+	walk->entrylen -= nbytes;
+	return nbytes;
+}
+
+static int hash_walk_new_entry(struct crypto_hash_walk *walk)
+{
+	struct scatterlist *sg;
+
+	sg = walk->sg;
+	walk->pg = sg_page(sg);
+	walk->offset = sg->offset;
+	walk->entrylen = sg->length;
+
+	if (walk->entrylen > walk->total)
+		walk->entrylen = walk->total;
+	walk->total -= walk->entrylen;
+
+	return hash_walk_next(walk);
+}
+
+int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
+{
+	unsigned int alignmask = walk->alignmask;
+	unsigned int nbytes = walk->entrylen;
+
+	walk->data -= walk->offset;
+
+	if (nbytes && walk->offset & alignmask && !err) {
+		walk->offset += alignmask - 1;
+		walk->offset = ALIGN(walk->offset, alignmask + 1);
+		walk->data += walk->offset;
+
+		nbytes = min(nbytes,
+			     ((unsigned int)(PAGE_SIZE)) - walk->offset);
+		walk->entrylen -= nbytes;
+
+		return nbytes;
+	}
+
+	crypto_kunmap(walk->data, 0);
+	crypto_yield(walk->flags);
+
+	if (err)
+		return err;
+
+	walk->offset = 0;
+
+	if (nbytes)
+		return hash_walk_next(walk);
+
+	if (!walk->total)
+		return 0;
+
+	walk->sg = scatterwalk_sg_next(walk->sg);
+
+	return hash_walk_new_entry(walk);
+}
+EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
+
+int crypto_hash_walk_first(struct ahash_request *req,
+			   struct crypto_hash_walk *walk)
+{
+	walk->total = req->nbytes;
+
+	if (!walk->total)
+		return 0;
+
+	walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
+	walk->sg = req->src;
+	walk->flags = req->base.flags;
+
+	return hash_walk_new_entry(walk);
+}
+EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
  
 static int ahash_setkey_unaligned(struct crypto_ahash *tfm, const u8 *key,
 				unsigned int keylen)
+/*
+ * Hash algorithms.
+ * 
+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the Free
+ * Software Foundation; either version 2 of the License, or (at your option) 
+ * any later version.
+ *
+ */
+
+#ifndef _CRYPTO_INTERNAL_HASH_H
+#define _CRYPTO_INTERNAL_HASH_H
+
+#include <crypto/algapi.h>
+
+struct ahash_request;
+struct scatterlist;
+
+struct crypto_hash_walk {
+	char *data;
+
+	unsigned int offset;
+	unsigned int alignmask;
+
+	struct page *pg;
+	unsigned int entrylen;
+
+	unsigned int total;
+	struct scatterlist *sg;
+
+	unsigned int flags;
+};
+
+int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err);
+int crypto_hash_walk_first(struct ahash_request *req,
+			   struct crypto_hash_walk *walk);
+
+#endif	/* _CRYPTO_INTERNAL_HASH_H */
...	...	@@ -13,7 +13,8 @@
13	13	*
14	14	*/
15	15
16		-#include <crypto/algapi.h>
	16	+#include <crypto/internal/hash.h>
	17	+#include <crypto/scatterwalk.h>
17	18	#include <linux/err.h>
18	19	#include <linux/kernel.h>
19	20	#include <linux/module.h>
...	...	@@ -22,6 +23,94 @@
22	23	#include <linux/seq_file.h>
23	24
24	25	#include "internal.h"
	26	+
	27	+static int hash_walk_next(struct crypto_hash_walk *walk)
	28	+{
	29	+ unsigned int alignmask = walk->alignmask;
	30	+ unsigned int offset = walk->offset;
	31	+ unsigned int nbytes = min(walk->entrylen,
	32	+ ((unsigned int)(PAGE_SIZE)) - offset);
	33	+
	34	+ walk->data = crypto_kmap(walk->pg, 0);
	35	+ walk->data += offset;
	36	+
	37	+ if (offset & alignmask)
	38	+ nbytes = alignmask + 1 - (offset & alignmask);
	39	+
	40	+ walk->entrylen -= nbytes;
	41	+ return nbytes;
	42	+}
	43	+
	44	+static int hash_walk_new_entry(struct crypto_hash_walk *walk)
	45	+{
	46	+ struct scatterlist *sg;
	47	+
	48	+ sg = walk->sg;
	49	+ walk->pg = sg_page(sg);
	50	+ walk->offset = sg->offset;
	51	+ walk->entrylen = sg->length;
	52	+
	53	+ if (walk->entrylen > walk->total)
	54	+ walk->entrylen = walk->total;
	55	+ walk->total -= walk->entrylen;
	56	+
	57	+ return hash_walk_next(walk);
	58	+}
	59	+
	60	+int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err)
	61	+{
	62	+ unsigned int alignmask = walk->alignmask;
	63	+ unsigned int nbytes = walk->entrylen;
	64	+
	65	+ walk->data -= walk->offset;
	66	+
	67	+ if (nbytes && walk->offset & alignmask && !err) {
	68	+ walk->offset += alignmask - 1;
	69	+ walk->offset = ALIGN(walk->offset, alignmask + 1);
	70	+ walk->data += walk->offset;
	71	+
	72	+ nbytes = min(nbytes,
	73	+ ((unsigned int)(PAGE_SIZE)) - walk->offset);
	74	+ walk->entrylen -= nbytes;
	75	+
	76	+ return nbytes;
	77	+ }
	78	+
	79	+ crypto_kunmap(walk->data, 0);
	80	+ crypto_yield(walk->flags);
	81	+
	82	+ if (err)
	83	+ return err;
	84	+
	85	+ walk->offset = 0;
	86	+
	87	+ if (nbytes)
	88	+ return hash_walk_next(walk);
	89	+
	90	+ if (!walk->total)
	91	+ return 0;
	92	+
	93	+ walk->sg = scatterwalk_sg_next(walk->sg);
	94	+
	95	+ return hash_walk_new_entry(walk);
	96	+}
	97	+EXPORT_SYMBOL_GPL(crypto_hash_walk_done);
	98	+
	99	+int crypto_hash_walk_first(struct ahash_request *req,
	100	+ struct crypto_hash_walk *walk)
	101	+{
	102	+ walk->total = req->nbytes;
	103	+
	104	+ if (!walk->total)
	105	+ return 0;
	106	+
	107	+ walk->alignmask = crypto_ahash_alignmask(crypto_ahash_reqtfm(req));
	108	+ walk->sg = req->src;
	109	+ walk->flags = req->base.flags;
	110	+
	111	+ return hash_walk_new_entry(walk);
	112	+}
	113	+EXPORT_SYMBOL_GPL(crypto_hash_walk_first);
25	114
26	115	static int ahash_setkey_unaligned(struct crypto_ahash tfm, const u8 key,
27	116	unsigned int keylen)
	1	+/*
	2	+ * Hash algorithms.
	3	+ *
	4	+ * Copyright (c) 2008 Herbert Xu <herbert@gondor.apana.org.au>
	5	+ *
	6	+ * This program is free software; you can redistribute it and/or modify it
	7	+ * under the terms of the GNU General Public License as published by the Free
	8	+ * Software Foundation; either version 2 of the License, or (at your option)
	9	+ * any later version.
	10	+ *
	11	+ */
	12	+
	13	+#ifndef _CRYPTO_INTERNAL_HASH_H
	14	+#define _CRYPTO_INTERNAL_HASH_H
	15	+
	16	+#include <crypto/algapi.h>
	17	+
	18	+struct ahash_request;
	19	+struct scatterlist;
	20	+
	21	+struct crypto_hash_walk {
	22	+ char *data;
	23	+
	24	+ unsigned int offset;
	25	+ unsigned int alignmask;
	26	+
	27	+ struct page *pg;
	28	+ unsigned int entrylen;
	29	+
	30	+ unsigned int total;
	31	+ struct scatterlist *sg;
	32	+
	33	+ unsigned int flags;
	34	+};
	35	+
	36	+int crypto_hash_walk_done(struct crypto_hash_walk *walk, int err);
	37	+int crypto_hash_walk_first(struct ahash_request *req,
	38	+ struct crypto_hash_walk *walk);
	39	+
	40	+#endif /* _CRYPTO_INTERNAL_HASH_H */