Thanks, Herbert, see my reply as below.
> 1) Utilise the brand new crypto ahash interface (note that it's
When you mentioned ahash, can you give a explanation on it?
The brand new crypto interface is different with crypto/api?
> designed to support sync just as well as async despite the name)
Do you mean use async_xxx interface?
> to rewrite the crypto/crc32c implementation such that one tfm can
> be used by multiple users. All that has to be done is to move
> the state from the tfm into the request object.
> 2) Convert all crc32c users to use the crypto interface and phase
> out lib/crc32c completely.
>
> 3) Add the Intel-specific crc32c implementation through the crypto
> API.
Agreed. And which module in crypto is the template for following the crypto API?
> That way none of this iffy testing will be necessary. Even better,
> most users can share one common tfm and therefore there will only
> be one test for the CPU flag at boot time rather than every time
> it's used.
>
> In fact, we could even skip 2) and reimplement lib/crc32c as a
> wrapper on the crypto crc32c interface with a shared tfm so you
> don't need to modify its existing users.
Good idea.
> Cheers,
Hi.
On Tue, Jul 08, 2008 at 06:25:54AM -0400, austin zhang ([email protected]) wrote:
> > designed to support sync just as well as async despite the name)
> Do you mean use async_xxx interface?
No, async_xxx is very different hardware assist, although it can be
converted to cryptoapi too.
> > to rewrite the crypto/crc32c implementation such that one tfm can
> > be used by multiple users. All that has to be done is to move
> > the state from the tfm into the request object.
>
> > 2) Convert all crc32c users to use the crypto interface and phase
> > out lib/crc32c completely.
> >
> > 3) Add the Intel-specific crc32c implementation through the crypto
> > API.
> Agreed. And which module in crypto is the template for following the crypto API?
This is some kind of how cbc(cipher) or ecb(cipher) templates are done:
cbc(aes), cbc(aes-i686) for example.
The same would be possible to do with crc32c but for checksumming (which
is effectively a hash).
--
Evgeniy Polyakov
On Tue, Jul 08, 2008 at 06:25:54AM -0400, austin zhang wrote:
>
> Agreed. And which module in crypto is the template for following the crypto API?
I've just converted the crc32c module over to the new interface.
You can use this as an example.
> > In fact, we could even skip 2) and reimplement lib/crc32c as a
> > wrapper on the crypto crc32c interface with a shared tfm so you
> > don't need to modify its existing users.
> Good idea.
Unfortunately this leads to nasty hacks because the existing
interface does chaining in a way that isn't easily mapped over
to the crypto API. However this is no great loss since there
is a grand total of two users in the tree :)
So my plan is to convert them and then remove the libcrc32c
interface completely.
commit d55f7a6c8efa17bcbc3b5d240cc72ed8a71196c2
Author: Herbert Xu <[email protected]>
Date: Tue Jul 8 20:54:28 2008 +0800
crypto: crc32c - Add ahash implementation
This patch reimplements crc32c using the ahash interface. This
allows one tfm to be used by an unlimited number of users provided
that they all use the same key (which all current crc32c users do).
Signed-off-by: Herbert Xu <[email protected]>
diff --git a/crypto/Kconfig b/crypto/Kconfig
index 43b7473..ea50357 100644
--- a/crypto/Kconfig
+++ b/crypto/Kconfig
@@ -213,7 +213,7 @@ comment "Digest"
config CRYPTO_CRC32C
tristate "CRC32c CRC algorithm"
- select CRYPTO_ALGAPI
+ select CRYPTO_HASH
select LIBCRC32C
help
Castagnoli, et al Cyclic Redundancy-Check Algorithm. Used
diff --git a/crypto/crc32c.c b/crypto/crc32c.c
index 0dcf64a..7049a98 100644
--- a/crypto/crc32c.c
+++ b/crypto/crc32c.c
@@ -5,20 +5,23 @@
*
* This module file is a wrapper to invoke the lib/crc32c routines.
*
+ * Copyright (c) 2008 Herbert Xu <[email protected]>
+ *
* 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.
*
*/
+
+#include <crypto/hash.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/string.h>
-#include <linux/crypto.h>
#include <linux/crc32c.h>
#include <linux/kernel.h>
-#define CHKSUM_BLOCK_SIZE 32
+#define CHKSUM_BLOCK_SIZE 1
#define CHKSUM_DIGEST_SIZE 4
struct chksum_ctx {
@@ -71,7 +74,7 @@ static void chksum_final(struct crypto_tfm *tfm, u8 *out)
*(__le32 *)out = ~cpu_to_le32(mctx->crc);
}
-static int crc32c_cra_init(struct crypto_tfm *tfm)
+static int crc32c_cra_init_old(struct crypto_tfm *tfm)
{
struct chksum_ctx *mctx = crypto_tfm_ctx(tfm);
@@ -79,14 +82,14 @@ static int crc32c_cra_init(struct crypto_tfm *tfm)
return 0;
}
-static struct crypto_alg alg = {
+static struct crypto_alg old_alg = {
.cra_name = "crc32c",
.cra_flags = CRYPTO_ALG_TYPE_DIGEST,
.cra_blocksize = CHKSUM_BLOCK_SIZE,
.cra_ctxsize = sizeof(struct chksum_ctx),
.cra_module = THIS_MODULE,
- .cra_list = LIST_HEAD_INIT(alg.cra_list),
- .cra_init = crc32c_cra_init,
+ .cra_list = LIST_HEAD_INIT(old_alg.cra_list),
+ .cra_init = crc32c_cra_init_old,
.cra_u = {
.digest = {
.dia_digestsize= CHKSUM_DIGEST_SIZE,
@@ -98,14 +101,125 @@ static struct crypto_alg alg = {
}
};
+/*
+ * Setting the seed allows arbitrary accumulators and flexible XOR policy
+ * If your algorithm starts with ~0, then XOR with ~0 before you set
+ * the seed.
+ */
+static int crc32c_setkey(struct crypto_ahash *hash, const u8 *key,
+ unsigned int keylen)
+{
+ u32 *mctx = crypto_ahash_ctx(hash);
+
+ if (keylen != sizeof(u32)) {
+ crypto_ahash_set_flags(hash, CRYPTO_TFM_RES_BAD_KEY_LEN);
+ return -EINVAL;
+ }
+ *mctx = le32_to_cpup((__le32 *)key);
+ return 0;
+}
+
+static int crc32c_init(struct ahash_request *req)
+{
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 *crcp = ahash_request_ctx(req);
+
+ *crcp = *mctx;
+ return 0;
+}
+
+static int crc32c_update(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *crcp = ahash_request_ctx(req);
+ u32 crc = *crcp;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c(crc, walk.data, nbytes);
+
+ *crcp = crc;
+ return 0;
+}
+
+static int crc32c_final(struct ahash_request *req)
+{
+ u32 *crcp = ahash_request_ctx(req);
+
+ *(__le32 *)req->result = ~cpu_to_le32p(crcp);
+ return 0;
+}
+
+static int crc32c_digest(struct ahash_request *req)
+{
+ struct crypto_hash_walk walk;
+ u32 *mctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
+ u32 crc = *mctx;
+ int nbytes;
+
+ for (nbytes = crypto_hash_walk_first(req, &walk); nbytes;
+ nbytes = crypto_hash_walk_done(&walk, 0))
+ crc = crc32c(crc, walk.data, nbytes);
+
+ *(__le32 *)req->result = ~cpu_to_le32(crc);
+ return 0;
+}
+
+static int crc32c_cra_init(struct crypto_tfm *tfm)
+{
+ u32 *key = crypto_tfm_ctx(tfm);
+
+ *key = ~0;
+
+ tfm->crt_ahash.reqsize = sizeof(u32);
+
+ return 0;
+}
+
+static struct crypto_alg alg = {
+ .cra_name = "crc32c",
+ .cra_driver_name = "crc32c-generic",
+ .cra_priority = 100,
+ .cra_flags = CRYPTO_ALG_TYPE_AHASH,
+ .cra_blocksize = CHKSUM_BLOCK_SIZE,
+ .cra_alignmask = 3,
+ .cra_ctxsize = sizeof(u32),
+ .cra_module = THIS_MODULE,
+ .cra_list = LIST_HEAD_INIT(alg.cra_list),
+ .cra_init = crc32c_cra_init,
+ .cra_type = &crypto_ahash_type,
+ .cra_u = {
+ .ahash = {
+ .digestsize = CHKSUM_DIGEST_SIZE,
+ .setkey = crc32c_setkey,
+ .init = crc32c_init,
+ .update = crc32c_update,
+ .final = crc32c_final,
+ .digest = crc32c_digest,
+ }
+ }
+};
+
static int __init crc32c_mod_init(void)
{
- return crypto_register_alg(&alg);
+ int err;
+
+ err = crypto_register_alg(&old_alg);
+ if (err)
+ return err;
+
+ err = crypto_register_alg(&alg);
+ if (err)
+ crypto_unregister_alg(&old_alg);
+
+ return err;
}
static void __exit crc32c_mod_fini(void)
{
crypto_unregister_alg(&alg);
+ crypto_unregister_alg(&old_alg);
}
module_init(crc32c_mod_init);
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
On Wed, 2008-07-09 at 15:41 +0800, Herbert Xu wrote:
> I've just converted the crc32c module over to the new interface.
> You can use this as an example.
Herbert and Evgeniy,
Sorry for late reply. Thanks a lot for your information and example, I
will work out the intel-specific implemetation. After internal
discussing and approval, I will post here for review again.
> Unfortunately this leads to nasty hacks because the existing
> interface does chaining in a way that isn't easily mapped over
> to the crypto API. However this is no great loss since there
> is a grand total of two users in the tree :)
>
> So my plan is to convert them and then remove the libcrc32c
> interface completely.
Because libcrc32c can be a module in original implemetation, so for
those other routine which call crc32c_le directly, this may not work for
them?
On Thu, Jul 10, 2008 at 07:26:09AM -0400, austin zhang wrote:
>
> > So my plan is to convert them and then remove the libcrc32c
> > interface completely.
> Because libcrc32c can be a module in original implemetation, so for
> those other routine which call crc32c_le directly, this may not work for
> them?
I've looked at them all (there are only three users of crc32c
in the tree) and they can all be converted across. I'll wait
for ahash to hit Linus's tree before starting the conversion.
Cheers,
--
Visit Openswan at http://www.openswan.org/
Email: Herbert Xu ~{PmV>HI~} <[email protected]>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt