include/crypto/lrw.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _CRYPTO_LRW_H
   3 #define _CRYPTO_LRW_H
   4
   5 #include <crypto/b128ops.h>
   6
   7 struct scatterlist;
   8 struct gf128mul_64k;
   9 struct blkcipher_desc;
  10
  11 #define LRW_BLOCK_SIZE 16
  12
  13 struct lrw_table_ctx {
  14         /* optimizes multiplying a random (non incrementing, as at the
  15          * start of a new sector) value with key2, we could also have
  16          * used 4k optimization tables or no optimization at all. In the
  17          * latter case we would have to store key2 here */
  18         struct gf128mul_64k *table;
  19         /* stores:
  20          *  key2*{ 0,0,...0,0,0,0,1 }, key2*{ 0,0,...0,0,0,1,1 },
  21          *  key2*{ 0,0,...0,0,1,1,1 }, key2*{ 0,0,...0,1,1,1,1 }
  22          *  key2*{ 0,0,...1,1,1,1,1 }, etc
  23          * needed for optimized multiplication of incrementing values
  24          * with key2 */
  25         be128 mulinc[128];
  26 };
  27
  28 int lrw_init_table(struct lrw_table_ctx *ctx, const u8 *tweak);
  29 void lrw_free_table(struct lrw_table_ctx *ctx);
  30
  31 struct lrw_crypt_req {
  32         be128 *tbuf;
  33         unsigned int tbuflen;
  34
  35         struct lrw_table_ctx *table_ctx;
  36         void *crypt_ctx;
  37         void (*crypt_fn)(void *ctx, u8 *blks, unsigned int nbytes);
  38 };
  39
  40 int lrw_crypt(struct blkcipher_desc *desc, struct scatterlist *dst,
  41               struct scatterlist *src, unsigned int nbytes,
  42               struct lrw_crypt_req *req);
  43
  44 #endif  /* _CRYPTO_LRW_H */