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/* SPDX-License-Identifier: Apache-2.0
* Copyright(c) 2024 Cisco Systems, Inc.
*/
#ifndef __crypto_aes_ctr_h__
#define __crypto_aes_ctr_h__
#include <vppinfra/clib.h>
#include <vppinfra/vector.h>
#include <vppinfra/cache.h>
#include <vppinfra/string.h>
#include <vppinfra/crypto/aes.h>
typedef struct
{
const aes_expaned_key_t exp_key[AES_KEY_ROUNDS (AES_KEY_256) + 1];
} aes_ctr_key_data_t;
typedef struct
{
const aes_expaned_key_t exp_key[AES_KEY_ROUNDS (AES_KEY_256) + 1];
aes_counter_t ctr; /* counter (reflected) */
u8 keystream_bytes[N_AES_BYTES]; /* keystream leftovers */
u32 n_keystream_bytes; /* number of keystream leftovers */
} aes_ctr_ctx_t;
static_always_inline aes_counter_t
aes_ctr_one_block (aes_ctr_ctx_t *ctx, aes_counter_t ctr, const u8 *src,
u8 *dst, u32 n_parallel, u32 n_bytes, int rounds, int last)
{
u32 __clib_aligned (N_AES_BYTES)
inc[] = { N_AES_LANES, 0, 0, 0, N_AES_LANES, 0, 0, 0,
N_AES_LANES, 0, 0, 0, N_AES_LANES, 0, 0, 0 };
const aes_expaned_key_t *k = ctx->exp_key;
const aes_mem_t *sv = (aes_mem_t *) src;
aes_mem_t *dv = (aes_mem_t *) dst;
aes_data_t d[4], t[4];
u32 r;
n_bytes -= (n_parallel - 1) * N_AES_BYTES;
/* AES First Round */
for (int i = 0; i < n_parallel; i++)
{
#if N_AES_LANES == 4
t[i] = k[0].x4 ^ (u8x64) aes_reflect ((u8x64) ctr);
#elif N_AES_LANES == 2
t[i] = k[0].x2 ^ (u8x32) aes_reflect ((u8x32) ctr);
#else
t[i] = k[0].x1 ^ (u8x16) aes_reflect ((u8x16) ctr);
#endif
ctr += *(aes_counter_t *) inc;
}
/* Load Data */
for (int i = 0; i < n_parallel - last; i++)
d[i] = sv[i];
if (last)
d[n_parallel - 1] =
aes_load_partial ((u8 *) (sv + n_parallel - 1), n_bytes);
/* AES Intermediate Rounds */
for (r = 1; r < rounds; r++)
aes_enc_round (t, k + r, n_parallel);
/* AES Last Round */
aes_enc_last_round (t, d, k + r, n_parallel);
/* Store Data */
for (int i = 0; i < n_parallel - last; i++)
dv[i] = d[i];
if (last)
{
aes_store_partial (d[n_parallel - 1], dv + n_parallel - 1, n_bytes);
*(aes_data_t *) ctx->keystream_bytes = t[n_parallel - 1];
ctx->n_keystream_bytes = N_AES_BYTES - n_bytes;
}
return ctr;
}
static_always_inline void
clib_aes_ctr_init (aes_ctr_ctx_t *ctx, const aes_ctr_key_data_t *kd,
const u8 *iv, aes_key_size_t ks)
{
u32x4 ctr = (u32x4) u8x16_reflect (*(u8x16u *) iv);
#if N_AES_LANES == 4
ctx->ctr = (aes_counter_t) u32x16_splat_u32x4 (ctr) +
(u32x16){ 0, 0, 0, 0, 1, 0, 0, 0, 2, 0, 0, 0, 3, 0, 0, 0 };
#elif N_AES_LANES == 2
ctx->ctr = (aes_counter_t) u32x8_splat_u32x4 (ctr) +
(u32x8){ 0, 0, 0, 0, 1, 0, 0, 0 };
#else
ctx->ctr = ctr;
#endif
for (int i = 0; i < AES_KEY_ROUNDS (ks) + 1; i++)
((aes_expaned_key_t *) ctx->exp_key)[i] = kd->exp_key[i];
ctx->n_keystream_bytes = 0;
}
static_always_inline void
clib_aes_ctr_transform (aes_ctr_ctx_t *ctx, const u8 *src, u8 *dst,
u32 n_bytes, aes_key_size_t ks)
{
int r = AES_KEY_ROUNDS (ks);
aes_counter_t ctr = ctx->ctr;
if (ctx->n_keystream_bytes)
{
u8 *ks = ctx->keystream_bytes + N_AES_BYTES - ctx->n_keystream_bytes;
if (ctx->n_keystream_bytes >= n_bytes)
{
for (int i = 0; i < n_bytes; i++)
dst[i] = src[i] ^ ks[i];
ctx->n_keystream_bytes -= n_bytes;
return;
}
for (int i = 0; i < ctx->n_keystream_bytes; i++)
dst++[0] = src++[0] ^ ks[i];
n_bytes -= ctx->n_keystream_bytes;
ctx->n_keystream_bytes = 0;
}
/* main loop */
for (int n = 4 * N_AES_BYTES; n_bytes >= n; n_bytes -= n, dst += n, src += n)
ctr = aes_ctr_one_block (ctx, ctr, src, dst, 4, n, r, 0);
if (n_bytes)
{
if (n_bytes > 3 * N_AES_BYTES)
ctr = aes_ctr_one_block (ctx, ctr, src, dst, 4, n_bytes, r, 1);
else if (n_bytes > 2 * N_AES_BYTES)
ctr = aes_ctr_one_block (ctx, ctr, src, dst, 3, n_bytes, r, 1);
else if (n_bytes > N_AES_BYTES)
ctr = aes_ctr_one_block (ctx, ctr, src, dst, 2, n_bytes, r, 1);
else
ctr = aes_ctr_one_block (ctx, ctr, src, dst, 1, n_bytes, r, 1);
}
else
ctx->n_keystream_bytes = 0;
ctx->ctr = ctr;
}
static_always_inline void
clib_aes_ctr_key_expand (aes_ctr_key_data_t *kd, const u8 *key,
aes_key_size_t ks)
{
u8x16 ek[AES_KEY_ROUNDS (AES_KEY_256) + 1];
aes_expaned_key_t *k = (aes_expaned_key_t *) kd->exp_key;
/* expand AES key */
aes_key_expand (ek, key, ks);
for (int i = 0; i < AES_KEY_ROUNDS (ks) + 1; i++)
k[i].lanes[0] = k[i].lanes[1] = k[i].lanes[2] = k[i].lanes[3] = ek[i];
}
static_always_inline void
clib_aes128_ctr (const aes_ctr_key_data_t *kd, const u8 *src, u32 n_bytes,
const u8 *iv, u8 *dst)
{
aes_ctr_ctx_t ctx;
clib_aes_ctr_init (&ctx, kd, iv, AES_KEY_128);
clib_aes_ctr_transform (&ctx, src, dst, n_bytes, AES_KEY_128);
}
static_always_inline void
clib_aes192_ctr (const aes_ctr_key_data_t *kd, const u8 *src, u32 n_bytes,
const u8 *iv, u8 *dst)
{
aes_ctr_ctx_t ctx;
clib_aes_ctr_init (&ctx, kd, iv, AES_KEY_192);
clib_aes_ctr_transform (&ctx, src, dst, n_bytes, AES_KEY_192);
}
static_always_inline void
clib_aes256_ctr (const aes_ctr_key_data_t *kd, const u8 *src, u32 n_bytes,
const u8 *iv, u8 *dst)
{
aes_ctr_ctx_t ctx;
clib_aes_ctr_init (&ctx, kd, iv, AES_KEY_256);
clib_aes_ctr_transform (&ctx, src, dst, n_bytes, AES_KEY_256);
}
#endif /* __crypto_aes_ctr_h__ */
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