crypto: lrw - add interface for parallelized cipher implementions

Export gf128mul table initialization routines and add lrw_crypt() function
that can be used by cipher implementations that can benefit from parallelized
cipher operations.

Signed-off-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 86 insertions, 20 deletions

diff --git a/crypto/lrw.c b/crypto/lrw.c
index 91c17fa1837..ba42acc4deb 100644
--- a/crypto/lrw.c
+++ b/crypto/lrw.c
@@ -3,7 +3,7 @@
  *
  * Copyright (c) 2006 Rik Snel <rsnel@cube.dyndns.org>
  *
- * Based om ecb.c
+ * Based on ecb.c
  * Copyright (c) 2006 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * This program is free software; you can redistribute it and/or modify it
@@ -16,6 +16,7 @@
  * http://www.mail-archive.com/stds-p1619@listserv.ieee.org/msg00173.html
  *
  * The test vectors are included in the testing module tcrypt.[ch] */
+
 #include <crypto/algapi.h>
 #include <linux/err.h>
 #include <linux/init.h>
@@ -26,23 +27,7 @@
 
 #include <crypto/b128ops.h>
 #include <crypto/gf128mul.h>
-
-#define LRW_BLOCK_SIZE 16
-
-struct lrw_table_ctx {
-        /* optimizes multiplying a random (non incrementing, as at the
-         * start of a new sector) value with key2, we could also have
-         * used 4k optimization tables or no optimization at all. In the
-         * latter case we would have to store key2 here */
-        struct gf128mul_64k *table;
-        /* stores:
-         *  key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
-         *  key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
-         *  key2*{ 0,0,...1,1,1,1,1 }, etc
-         * needed for optimized multiplication of incrementing values
-         * with key2 */
-        be128 mulinc[128];
-};
+#include <crypto/lrw.h>
 
 struct priv {
         struct crypto_cipher *child;
@@ -60,7 +45,7 @@ static inline void setbit128_bbe(void *b, int bit)
                         ), b);
 }
 
-static int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
+int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
 {
         be128 tmp = { 0 };
         int i;
@@ -82,12 +67,14 @@ static int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak)
 
         return 0;
 }
+EXPORT_SYMBOL_GPL(lrw_init_table);
 
-static void lrw_free_table(struct lrw_table_ctx *ctx)
+void lrw_free_table(struct lrw_table_ctx *ctx)
 {
         if (ctx->table)
                 gf128mul_free_64k(ctx->table);
 }
+EXPORT_SYMBOL_GPL(lrw_free_table);
 
 static int setkey(struct crypto_tfm *parent, const u8 *key,
                   unsigned int keylen)
@@ -227,6 +214,85 @@ static int decrypt(struct blkcipher_desc *desc, struct scatterlist *dst,
                      crypto_cipher_alg(ctx->child)->cia_decrypt);
 }
 
+int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *sdst,
+              struct scatterlist *ssrc, unsigned int nbytes,
+              struct lrw_crypt_req *req)
+{
+        const unsigned int bsize = LRW_BLOCK_SIZE;
+        const unsigned int max_blks = req->tbuflen / bsize;
+        struct lrw_table_ctx *ctx = req->table_ctx;
+        struct blkcipher_walk walk;
+        unsigned int nblocks;
+        be128 *iv, *src, *dst, *t;
+        be128 *t_buf = req->tbuf;
+        int err, i;
+
+        BUG_ON(max_blks < 1);
+
+        blkcipher_walk_init(&walk, sdst, ssrc, nbytes);
+
+        err = blkcipher_walk_virt(desc, &walk);
+        nbytes = walk.nbytes;
+        if (!nbytes)
+                return err;
+
+        nblocks = min(walk.nbytes / bsize, max_blks);
+        src = (be128 *)walk.src.virt.addr;
+        dst = (be128 *)walk.dst.virt.addr;
+
+        /* calculate first value of T */
+        iv = (be128 *)walk.iv;
+        t_buf[0] = *iv;
+
+        /* T <- I*Key2 */
+        gf128mul_64k_bbe(&t_buf[0], ctx->table);
+
+        i = 0;
+        goto first;
+
+        for (;;) {
+                do {
+                        for (i = 0; i < nblocks; i++) {
+                                /* T <- I*Key2, using the optimization
+                                 * discussed in the specification */
+                                be128_xor(&t_buf[i], t,
+                                                &ctx->mulinc[get_index128(iv)]);
+                                inc(iv);
+first:
+                                t = &t_buf[i];
+
+                                /* PP <- T xor P */
+                                be128_xor(dst + i, t, src + i);
+                        }
+
+                        /* CC <- E(Key2,PP) */
+                        req->crypt_fn(req->crypt_ctx, (u8 *)dst,
+                                      nblocks * bsize);
+
+                        /* C <- T xor CC */
+                        for (i = 0; i < nblocks; i++)
+                                be128_xor(dst + i, dst + i, &t_buf[i]);
+
+                        src += nblocks;
+                        dst += nblocks;
+                        nbytes -= nblocks * bsize;
+                        nblocks = min(nbytes / bsize, max_blks);
+                } while (nblocks > 0);
+
+                err = blkcipher_walk_done(desc, &walk, nbytes);
+                nbytes = walk.nbytes;
+                if (!nbytes)
+                        break;
+
+                nblocks = min(nbytes / bsize, max_blks);
+                src = (be128 *)walk.src.virt.addr;
+                dst = (be128 *)walk.dst.virt.addr;
+        }
+
+        return err;
+}
+EXPORT_SYMBOL_GPL(lrw_crypt);
+
 static int init_tfm(struct crypto_tfm *tfm)
 {
         struct crypto_cipher *cipher;