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/*
* This code is based on Ted Krovetz's ChaCha implementation; details below.
*
* Note that I've ripped out all of the code that wasn't suitable for doing
* block-oriented operation, all (residual) support for 128-bit ChaCha keys,
* all (partial) support for counter values over 32 bits, the ability to xor
* the stream with a plaintext, and so on.
*
* Future versions of this might remove bigendian conversions too. DO NOT use
* this code for your stream cipher: go back to the original source. (I got
* this copy from SUPERCOP).
*/
/* Chacha implementation for 16-byte vectors by Ted Krovetz (ted@krovetz.net).
* Assumes 32-bit int, 64-bit long long. Public domain. Modified: 2012.07.26.
* Chacha is an improvement on the stream cipher Salsa, described at
* http://cr.yp.to/papers.html#chacha
*/
#include <string.h>
#include <assert.h>
#include "ottery-internal.h"
/* Architecture-neutral way to specify 16-byte vector of ints */
typedef unsigned vec __attribute__ ((vector_size (16)));
/* This implementation is designed for Neon, SSE and AltiVec machines. The
* following specify how to do certain vector operations efficiently on
* each architecture, using intrinsics.
* This implementation supports parallel processing of multiple blocks,
* including potentially using general-purpose registers.
*/
#if __ARM_NEON__
#include <arm_neon.h>
#define GPR_TOO 1
#define VBPI 2
#define ONE (vec)vsetq_lane_u32(1,vdupq_n_u32(0),0)
#define NONCE(ctr,p) (vec)vcombine_u32(vcreate_u32(ctr),vcreate_u32(*(uint64_t *)p))
#define ROTV1(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,1)
#define ROTV2(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,2)
#define ROTV3(x) (vec)vextq_u32((uint32x4_t)x,(uint32x4_t)x,3)
#define ROTW16(x) (vec)vrev32q_u16((uint16x8_t)x)
#if __clang__
#define ROTW7(x) (x << ((vec){ 7, 7, 7, 7})) ^ (x >> ((vec){25,25,25,25}))
#define ROTW8(x) (x << ((vec){ 8, 8, 8, 8})) ^ (x >> ((vec){24,24,24,24}))
#define ROTW12(x) (x << ((vec){12,12,12,12})) ^ (x >> ((vec){20,20,20,20}))
#else
#define ROTW7(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,7),(uint32x4_t)x,25)
#define ROTW8(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,8),(uint32x4_t)x,24)
#define ROTW12(x) (vec)vsriq_n_u32(vshlq_n_u32((uint32x4_t)x,12),(uint32x4_t)x,20)
#endif
#elif __ALTIVEC__
#include <altivec.h>
#define GPR_TOO 1
#define VBPI 3
#define ONE ((vec){1,0,0,0})
#define NONCE(ctr,p) vec_sro(*(vec *)p, (vector char)(vec){0,0,0,8*8})+((vec){((ctr)&0xffffffff), (ctr)>>32, 0, 0})
#error "Don't use this code till it can be tested on altivec"
#define REVW_BE(x) __builtin_bswap32(x)
#define REVV_BE(x) vec_perm(x,x,(vector char){3,2,1,0,7,6,5,4,11,10,9,8,15,14,13,12})
#define ROTV1(x) vec_perm(x,x,(vector char){4,5,6,7,8,9,10,11,12,13,14,15,0,1,2,3})
#define ROTV2(x) vec_perm(x,x,(vector char){8,9,10,11,12,13,14,15,0,1,2,3,4,5,6,7})
#define ROTV3(x) vec_perm(x,x,(vector char){12,13,14,15,0,1,2,3,4,5,6,7,8,9,10,11})
#define ROTW7(x) vec_rl(x,vec_splat_u32(7))
#define ROTW8(x) vec_rl(x,vec_splat_u32(8))
#define ROTW12(x) vec_rl(x,vec_splat_u32(12))
#define ROTW16(x) vec_rl(x,vec_splat_u32(-16)) /* trick to get 16 */
#elif __SSE2__
#include <emmintrin.h>
#define GPR_TOO 0
#if __clang__
#define VBPI 4
#else
#define VBPI 3
#endif
#define ONE (vec)_mm_set_epi32(0,0,0,1)
#define NONCE(ctr,p) (vec)(_mm_slli_si128(_mm_loadl_epi64((__m128i *)(p)),8)+_mm_set_epi64x(0,ctr))
#define ROTV1(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(0,3,2,1))
#define ROTV2(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(1,0,3,2))
#define ROTV3(x) (vec)_mm_shuffle_epi32((__m128i)x,_MM_SHUFFLE(2,1,0,3))
#define ROTW7(x) (vec)(_mm_slli_epi32((__m128i)x, 7) ^ _mm_srli_epi32((__m128i)x,25))
#define ROTW12(x) (vec)(_mm_slli_epi32((__m128i)x,12) ^ _mm_srli_epi32((__m128i)x,20))
#if __SSSE3__
#include <tmmintrin.h>
#define ROTW8(x) (vec)_mm_shuffle_epi8((__m128i)x,_mm_set_epi8(14,13,12,15,10,9,8,11,6,5,4,7,2,1,0,3))
#define ROTW16(x) (vec)_mm_shuffle_epi8((__m128i)x,_mm_set_epi8(13,12,15,14,9,8,11,10,5,4,7,6,1,0,3,2))
#else
#define ROTW8(x) (vec)(_mm_slli_epi32((__m128i)x, 8) ^ _mm_srli_epi32((__m128i)x,24))
#define ROTW16(x) (vec)(_mm_slli_epi32((__m128i)x,16) ^ _mm_srli_epi32((__m128i)x,16))
#endif
#else
#error -- Implementation supports only machines with neon, altivec or SSE2
#endif
#ifndef REVV_BE
#define REVV_BE(x) (x)
#endif
#ifndef REVW_BE
#define REVW_BE(x) (x)
#endif
#define BPI (VBPI + GPR_TOO) /* Blocks computed per loop iteration */
#define DQROUND_VECTORS(a,b,c,d) \
a += b; d ^= a; d = ROTW16(d); \
c += d; b ^= c; b = ROTW12(b); \
a += b; d ^= a; d = ROTW8(d); \
c += d; b ^= c; b = ROTW7(b); \
b = ROTV1(b); c = ROTV2(c); d = ROTV3(d); \
a += b; d ^= a; d = ROTW16(d); \
c += d; b ^= c; b = ROTW12(b); \
a += b; d ^= a; d = ROTW8(d); \
c += d; b ^= c; b = ROTW7(b); \
b = ROTV3(b); c = ROTV2(c); d = ROTV1(d);
#define QROUND_WORDS(a,b,c,d) \
a = a+b; d ^= a; d = d<<16 | d>>16; \
c = c+d; b ^= c; b = b<<12 | b>>20; \
a = a+b; d ^= a; d = d<< 8 | d>>24; \
c = c+d; b ^= c; b = b<< 7 | b>>25;
#define WRITE(op, d, v0, v1, v2, v3) \
*(vec *)(op + d + 0) = REVV_BE(v0); \
*(vec *)(op + d + 4) = REVV_BE(v1); \
*(vec *)(op + d + 8) = REVV_BE(v2); \
*(vec *)(op + d + 12) = REVV_BE(v3);
struct chacha_state_krovetz {
__attribute__ ((aligned (16))) uint8_t key[32];
__attribute__ ((aligned (16))) uint8_t nonce[8];
};
#define LOOP_ITERATIONS 4
static inline int
ottery_blocks_chacha_krovetz(
const int chacha_rounds,
uint8_t *out,
uint32_t block_idx,
struct chacha_state_krovetz *st)
__attribute__((always_inline));
/** Generates 64 * BPI * LOOP_ITERATIONS bytes of output using the key and
* nonce in st and the counter in block_idx, and store them in out.
*/
static inline int
ottery_blocks_chacha_krovetz(
const int chacha_rounds,
uint8_t *out,
uint32_t block_idx,
struct chacha_state_krovetz *st)
/* Assumes all pointers are aligned properly for vector reads */
{
const unsigned char *k = st->key;
const unsigned char *n = st->nonce;
unsigned i, j, *op=(unsigned *)out, *kp, *np;
__attribute__ ((aligned (16))) unsigned chacha_const[] =
{0x61707865,0x3320646E,0x79622D32,0x6B206574};
#if ( __ARM_NEON__ || __SSE2__)
kp = (unsigned *)k;
np = (unsigned *)n;
#else
__attribute__ ((aligned (16))) unsigned key[8], nonce[2];
((vec *)key)[0] = REVV_BE(((vec *)k)[0]);
((vec *)key)[1] = REVV_BE(((vec *)k)[1]);
nonce[0] = REVW_BE(((unsigned *)n)[0]);
nonce[1] = REVW_BE(((unsigned *)n)[1]);
kp = (unsigned *)key;
np = (unsigned *)nonce;
#endif
vec s0 = *(vec *)chacha_const;
vec s1 = ((vec *)kp)[0];
vec s2 = ((vec *)kp)[1];
vec s3 = NONCE(block_idx, np);
for (j = 0; j < LOOP_ITERATIONS; ++j) {
vec v0,v1,v2,v3,v4,v5,v6,v7;
v4 = v0 = s0; v5 = v1 = s1; v6 = v2 = s2; v3 = s3;
v7 = v3 + ONE;
#if VBPI > 2
vec v8,v9,v10,v11;
v8 = v4; v9 = v5; v10 = v6;
v11 = v7 + ONE;
#endif
#if VBPI > 3
vec v12,v13,v14,v15;
v12 = v8; v13 = v9; v14 = v10;
v15 = v11 + ONE;
#endif
#if GPR_TOO
register unsigned x0, x1, x2, x3, x4, x5, x6, x7, x8,
x9, x10, x11, x12, x13, x14, x15;
x0 = chacha_const[0]; x1 = chacha_const[1];
x2 = chacha_const[2]; x3 = chacha_const[3];
x4 = kp[0]; x5 = kp[1]; x6 = kp[2]; x7 = kp[3];
x8 = kp[4]; x9 = kp[5]; x10 = kp[6]; x11 = kp[7];
const uint64_t x_ctr = block_idx + BPI*iters+(BPI-1);
x12 = x_ctr & 0xffffffff; x13 = x_ctr>>32; x14 = np[0]; x15 = np[1];
#endif
for (i = chacha_rounds/2; i; i--) {
DQROUND_VECTORS(v0,v1,v2,v3)
DQROUND_VECTORS(v4,v5,v6,v7)
#if VBPI > 2
DQROUND_VECTORS(v8,v9,v10,v11)
#endif
#if VBPI > 3
DQROUND_VECTORS(v12,v13,v14,v15)
#endif
#if GPR_TOO
QROUND_WORDS( x0, x4, x8,x12)
QROUND_WORDS( x1, x5, x9,x13)
QROUND_WORDS( x2, x6,x10,x14)
QROUND_WORDS( x3, x7,x11,x15)
QROUND_WORDS( x0, x5,x10,x15)
QROUND_WORDS( x1, x6,x11,x12)
QROUND_WORDS( x2, x7, x8,x13)
QROUND_WORDS( x3, x4, x9,x14)
#endif
}
WRITE(op, 0, v0+s0, v1+s1, v2+s2, v3+s3)
s3 += ONE;
WRITE(op, 16, v4+s0, v5+s1, v6+s2, v7+s3)
s3 += ONE;
#if VBPI > 2
WRITE(op, 32, v8+s0, v9+s1, v10+s2, v11+s3)
s3 += ONE;
#endif
#if VBPI > 3
WRITE(op, 48, v12+s0, v13+s1, v14+s2, v15+s3)
s3 += ONE;
#endif
op += VBPI*16;
#if GPR_TOO
op[0] = REVW_BE((x0 + chacha_const[0]));
op[1] = REVW_BE((x1 + chacha_const[1]));
op[2] = REVW_BE((x2 + chacha_const[2]));
op[3] = REVW_BE((x3 + chacha_const[3]));
op[4] = REVW_BE((x4 + kp[0]));
op[5] = REVW_BE((x5 + kp[1]));
op[6] = REVW_BE((x6 + kp[2]));
op[7] = REVW_BE((x7 + kp[3]));
op[8] = REVW_BE((x8 + kp[4]));
op[9] = REVW_BE((x9 + kp[5]));
op[10] = REVW_BE((x10 + kp[6]));
op[11] = REVW_BE((x11 + kp[7]));
op[12] = REVW_BE((x12 + (x_ctr & 0xffffffff)));
op[13] = REVW_BE((x13 + (x_ctr >> 32)));
op[14] = REVW_BE((x14 + np[0]));
op[15] = REVW_BE((x15 + np[1]));
s3 += ONE;
op += 16;
#endif
}
return 0;
}
#define STATE_LEN (sizeof(struct chacha_state_krovetz))
#define STATE_BYTES 40
#define IDX_STEP (BPI * LOOP_ITERATIONS)
#define OUTPUT_LEN (IDX_STEP * 64)
static void
chacha_krovetz_state_setup(void *state, const uint8_t *bytes)
{
struct chacha_state_krovetz *st = state;
memcpy(st->key, bytes, 32);
memcpy(st->nonce, bytes+32, 8);
}
static void
chacha8_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
{
struct chacha_state_krovetz *st = state;
ottery_blocks_chacha_krovetz(8, output, idx * IDX_STEP, st);
}
static void
chacha12_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
{
struct chacha_state_krovetz *st = state;
ottery_blocks_chacha_krovetz(12, output, idx * IDX_STEP, st);
}
static void
chacha20_krovetz_generate(void *state, uint8_t *output, uint32_t idx)
{
struct chacha_state_krovetz *st = state;
ottery_blocks_chacha_krovetz(20, output, idx * IDX_STEP, st);
}
#ifdef __SSSE3__
#define NEED_CPUCAP OTTERY_CPUCAP_SSSE3|OTTERY_CPUCAP_SIMD
#define FLAV "-SSSE3"
#else
#define NEED_CPUCAP OTTERY_CPUCAP_SIMD
#define FLAV "-DEFAULT"
#endif
#define PRF_CHACHA(r) { \
"CHACHA" #r, \
"CHACHA" #r "-SIMD", \
"CHACHA" #r "-SIMD" FLAV, \
STATE_LEN, \
STATE_BYTES, \
OUTPUT_LEN, \
NEED_CPUCAP, \
chacha_krovetz_state_setup, \
chacha ## r ## _krovetz_generate \
}
#if defined OTTERY_BUILDING_SIMD1
const struct ottery_prf ottery_prf_chacha8_krovetz_1_ = PRF_CHACHA(8);
const struct ottery_prf ottery_prf_chacha12_krovetz_1_ = PRF_CHACHA(12);
const struct ottery_prf ottery_prf_chacha20_krovetz_1_ = PRF_CHACHA(20);
#elif defined OTTERY_BUILDING_SIMD2
const struct ottery_prf ottery_prf_chacha8_krovetz_2_ = PRF_CHACHA(8);
const struct ottery_prf ottery_prf_chacha12_krovetz_2_ = PRF_CHACHA(12);
const struct ottery_prf ottery_prf_chacha20_krovetz_2_ = PRF_CHACHA(20);
#else
#error "Which PRF symbols am I supposed to define?"
#endif
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