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/*
This file is part of ethash.
ethash 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 3 of the License, or
(at your option) any later version.
ethash is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with cpp-ethereum. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file internal.c
* @author Tim Hughes <tim@twistedfury.com>
* @author Matthew Wampler-Doty
* @date 2015
*/
#include <assert.h>
#include <inttypes.h>
#include <stddef.h>
#include <errno.h>
#include <math.h>
#include "mmap.h"
#include "ethash.h"
#include "fnv.h"
#include "endian.h"
#include "internal.h"
#include "data_sizes.h"
#include "io.h"
#ifdef WITH_CRYPTOPP
#include "sha3_cryptopp.h"
#else
#include "sha3.h"
#endif // WITH_CRYPTOPP
uint64_t ethash_get_datasize(uint64_t const block_number)
{
assert(block_number / ETHASH_EPOCH_LENGTH < 2048);
return dag_sizes[block_number / ETHASH_EPOCH_LENGTH];
}
uint64_t ethash_get_cachesize(uint64_t const block_number)
{
assert(block_number / ETHASH_EPOCH_LENGTH < 2048);
return cache_sizes[block_number / ETHASH_EPOCH_LENGTH];
}
// Follows Sergio's "STRICT MEMORY HARD HASHING FUNCTIONS" (2014)
// https://bitslog.files.wordpress.com/2013/12/memohash-v0-3.pdf
// SeqMemoHash(s, R, N)
bool static ethash_compute_cache_nodes(
node* const nodes,
uint64_t cache_size,
ethash_h256_t const* seed
)
{
if (cache_size % sizeof(node) != 0) {
return false;
}
uint32_t const num_nodes = (uint32_t) (cache_size / sizeof(node));
SHA3_512(nodes[0].bytes, (uint8_t*)seed, 32);
for (uint32_t i = 1; i != num_nodes; ++i) {
SHA3_512(nodes[i].bytes, nodes[i - 1].bytes, 64);
}
for (uint32_t j = 0; j != ETHASH_CACHE_ROUNDS; j++) {
for (uint32_t i = 0; i != num_nodes; i++) {
uint32_t const idx = nodes[i].words[0] % num_nodes;
node data;
data = nodes[(num_nodes - 1 + i) % num_nodes];
for (uint32_t w = 0; w != NODE_WORDS; ++w) {
data.words[w] ^= nodes[idx].words[w];
}
SHA3_512(nodes[i].bytes, data.bytes, sizeof(data));
}
}
// now perform endian conversion
fix_endian_arr32(nodes->words, num_nodes * NODE_WORDS);
return true;
}
void ethash_calculate_dag_item(
node* const ret,
uint32_t node_index,
ethash_light_t const light
)
{
uint32_t num_parent_nodes = (uint32_t) (light->cache_size / sizeof(node));
node const* cache_nodes = (node const *) light->cache;
node const* init = &cache_nodes[node_index % num_parent_nodes];
memcpy(ret, init, sizeof(node));
ret->words[0] ^= node_index;
SHA3_512(ret->bytes, ret->bytes, sizeof(node));
#if defined(_M_X64) && ENABLE_SSE
__m128i const fnv_prime = _mm_set1_epi32(FNV_PRIME);
__m128i xmm0 = ret->xmm[0];
__m128i xmm1 = ret->xmm[1];
__m128i xmm2 = ret->xmm[2];
__m128i xmm3 = ret->xmm[3];
#endif
for (uint32_t i = 0; i != ETHASH_DATASET_PARENTS; ++i) {
uint32_t parent_index = fnv_hash(node_index ^ i, ret->words[i % NODE_WORDS]) % num_parent_nodes;
node const *parent = &cache_nodes[parent_index];
#if defined(_M_X64) && ENABLE_SSE
{
xmm0 = _mm_mullo_epi32(xmm0, fnv_prime);
xmm1 = _mm_mullo_epi32(xmm1, fnv_prime);
xmm2 = _mm_mullo_epi32(xmm2, fnv_prime);
xmm3 = _mm_mullo_epi32(xmm3, fnv_prime);
xmm0 = _mm_xor_si128(xmm0, parent->xmm[0]);
xmm1 = _mm_xor_si128(xmm1, parent->xmm[1]);
xmm2 = _mm_xor_si128(xmm2, parent->xmm[2]);
xmm3 = _mm_xor_si128(xmm3, parent->xmm[3]);
// have to write to ret as values are used to compute index
ret->xmm[0] = xmm0;
ret->xmm[1] = xmm1;
ret->xmm[2] = xmm2;
ret->xmm[3] = xmm3;
}
#else
{
for (unsigned w = 0; w != NODE_WORDS; ++w) {
ret->words[w] = fnv_hash(ret->words[w], parent->words[w]);
}
}
#endif
}
SHA3_512(ret->bytes, ret->bytes, sizeof(node));
}
bool ethash_compute_full_data(
void* mem,
uint64_t full_size,
ethash_light_t const light,
ethash_callback_t callback
)
{
if (full_size % (sizeof(uint32_t) * MIX_WORDS) != 0 ||
(full_size % sizeof(node)) != 0) {
return false;
}
uint32_t const max_n = (uint32_t)(full_size / sizeof(node));
node* full_nodes = mem;
double const progress_change = 1.0f / max_n;
double progress = 0.0f;
// now compute full nodes
for (uint32_t n = 0; n != max_n; ++n) {
if (callback &&
n % (max_n / 100) == 0 &&
callback((unsigned int)(ceil(progress * 100.0f))) != 0) {
return false;
}
progress += progress_change;
ethash_calculate_dag_item(&(full_nodes[n]), n, light);
}
return true;
}
static bool ethash_hash(
ethash_return_value_t* ret,
node const* full_nodes,
ethash_light_t const light,
uint64_t full_size,
ethash_h256_t const header_hash,
uint64_t const nonce
)
{
if (full_size % MIX_WORDS != 0) {
return false;
}
// pack hash and nonce together into first 40 bytes of s_mix
assert(sizeof(node) * 8 == 512);
node s_mix[MIX_NODES + 1];
memcpy(s_mix[0].bytes, &header_hash, 32);
fix_endian64(s_mix[0].double_words[4], nonce);
// compute sha3-512 hash and replicate across mix
SHA3_512(s_mix->bytes, s_mix->bytes, 40);
fix_endian_arr32(s_mix[0].words, 16);
node* const mix = s_mix + 1;
for (uint32_t w = 0; w != MIX_WORDS; ++w) {
mix->words[w] = s_mix[0].words[w % NODE_WORDS];
}
unsigned const page_size = sizeof(uint32_t) * MIX_WORDS;
unsigned const num_full_pages = (unsigned) (full_size / page_size);
for (unsigned i = 0; i != ETHASH_ACCESSES; ++i) {
uint32_t const index = fnv_hash(s_mix->words[0] ^ i, mix->words[i % MIX_WORDS]) % num_full_pages;
for (unsigned n = 0; n != MIX_NODES; ++n) {
node const* dag_node;
if (full_nodes) {
dag_node = &full_nodes[MIX_NODES * index + n];
} else {
node tmp_node;
ethash_calculate_dag_item(&tmp_node, index * MIX_NODES + n, light);
dag_node = &tmp_node;
}
#if defined(_M_X64) && ENABLE_SSE
{
__m128i fnv_prime = _mm_set1_epi32(FNV_PRIME);
__m128i xmm0 = _mm_mullo_epi32(fnv_prime, mix[n].xmm[0]);
__m128i xmm1 = _mm_mullo_epi32(fnv_prime, mix[n].xmm[1]);
__m128i xmm2 = _mm_mullo_epi32(fnv_prime, mix[n].xmm[2]);
__m128i xmm3 = _mm_mullo_epi32(fnv_prime, mix[n].xmm[3]);
mix[n].xmm[0] = _mm_xor_si128(xmm0, dag_node->xmm[0]);
mix[n].xmm[1] = _mm_xor_si128(xmm1, dag_node->xmm[1]);
mix[n].xmm[2] = _mm_xor_si128(xmm2, dag_node->xmm[2]);
mix[n].xmm[3] = _mm_xor_si128(xmm3, dag_node->xmm[3]);
}
#else
{
for (unsigned w = 0; w != NODE_WORDS; ++w) {
mix[n].words[w] = fnv_hash(mix[n].words[w], dag_node->words[w]);
}
}
#endif
}
}
// compress mix
for (uint32_t w = 0; w != MIX_WORDS; w += 4) {
uint32_t reduction = mix->words[w + 0];
reduction = reduction * FNV_PRIME ^ mix->words[w + 1];
reduction = reduction * FNV_PRIME ^ mix->words[w + 2];
reduction = reduction * FNV_PRIME ^ mix->words[w + 3];
mix->words[w / 4] = reduction;
}
fix_endian_arr32(mix->words, MIX_WORDS / 4);
memcpy(&ret->mix_hash, mix->bytes, 32);
// final Keccak hash
SHA3_256(&ret->result, s_mix->bytes, 64 + 32); // Keccak-256(s + compressed_mix)
return true;
}
void ethash_quick_hash(
ethash_h256_t* return_hash,
ethash_h256_t const* header_hash,
uint64_t const nonce,
ethash_h256_t const* mix_hash
)
{
uint8_t buf[64 + 32];
memcpy(buf, header_hash, 32);
fix_endian64_same(nonce);
memcpy(&(buf[32]), &nonce, 8);
SHA3_512(buf, buf, 40);
memcpy(&(buf[64]), mix_hash, 32);
SHA3_256(return_hash, buf, 64 + 32);
}
ethash_h256_t ethash_get_seedhash(uint64_t block_number)
{
ethash_h256_t ret;
ethash_h256_reset(&ret);
uint64_t const epochs = block_number / ETHASH_EPOCH_LENGTH;
for (uint32_t i = 0; i < epochs; ++i)
SHA3_256(&ret, (uint8_t*)&ret, 32);
return ret;
}
bool ethash_quick_check_difficulty(
ethash_h256_t const* header_hash,
uint64_t const nonce,
ethash_h256_t const* mix_hash,
ethash_h256_t const* difficulty
)
{
ethash_h256_t return_hash;
ethash_quick_hash(&return_hash, header_hash, nonce, mix_hash);
return ethash_check_difficulty(&return_hash, difficulty);
}
ethash_light_t ethash_light_new_internal(uint64_t cache_size, ethash_h256_t const* seed)
{
struct ethash_light *ret;
ret = calloc(sizeof(*ret), 1);
if (!ret) {
return NULL;
}
ret->cache = malloc((size_t)cache_size);
if (!ret->cache) {
goto fail_free_light;
}
node* nodes = (node*)ret->cache;
if (!ethash_compute_cache_nodes(nodes, cache_size, seed)) {
goto fail_free_cache_mem;
}
ret->cache_size = cache_size;
return ret;
fail_free_cache_mem:
free(ret->cache);
fail_free_light:
free(ret);
return NULL;
}
ethash_light_t ethash_light_new(uint64_t block_number)
{
ethash_h256_t seedhash = ethash_get_seedhash(block_number);
ethash_light_t ret;
ret = ethash_light_new_internal(ethash_get_cachesize(block_number), &seedhash);
ret->block_number = block_number;
return ret;
}
void ethash_light_delete(ethash_light_t light)
{
if (light->cache) {
free(light->cache);
}
free(light);
}
ethash_return_value_t ethash_light_compute_internal(
ethash_light_t light,
uint64_t full_size,
ethash_h256_t const header_hash,
uint64_t nonce
)
{
ethash_return_value_t ret;
ret.success = true;
if (!ethash_hash(&ret, NULL, light, full_size, header_hash, nonce)) {
ret.success = false;
}
return ret;
}
ethash_return_value_t ethash_light_compute(
ethash_light_t light,
ethash_h256_t const header_hash,
uint64_t nonce
)
{
uint64_t full_size = ethash_get_datasize(light->block_number);
return ethash_light_compute_internal(light, full_size, header_hash, nonce);
}
static bool ethash_mmap(struct ethash_full* ret, FILE* f)
{
int fd;
char* mmapped_data;
ret->file = f;
if ((fd = ethash_fileno(ret->file)) == -1) {
return false;
}
mmapped_data= mmap(
NULL,
(size_t)ret->file_size + ETHASH_DAG_MAGIC_NUM_SIZE,
PROT_READ | PROT_WRITE,
MAP_SHARED,
fd,
0
);
if (mmapped_data == MAP_FAILED) {
return false;
}
ret->data = (node*)(mmapped_data + ETHASH_DAG_MAGIC_NUM_SIZE);
return true;
}
ethash_full_t ethash_full_new_internal(
char const* dirname,
ethash_h256_t const seed_hash,
uint64_t full_size,
ethash_light_t const light,
ethash_callback_t callback
)
{
struct ethash_full* ret;
FILE *f = NULL;
ret = calloc(sizeof(*ret), 1);
if (!ret) {
return NULL;
}
ret->file_size = (size_t)full_size;
switch (ethash_io_prepare(dirname, seed_hash, &f, (size_t)full_size, false)) {
case ETHASH_IO_FAIL:
goto fail_free_full;
case ETHASH_IO_MEMO_MATCH:
if (!ethash_mmap(ret, f)) {
goto fail_close_file;
}
return ret;
case ETHASH_IO_MEMO_SIZE_MISMATCH:
// if a DAG of same filename but unexpected size is found, silently force new file creation
if (ethash_io_prepare(dirname, seed_hash, &f, (size_t)full_size, true) != ETHASH_IO_MEMO_MISMATCH) {
goto fail_free_full;
}
// fallthrough to the mismatch case here, DO NOT go through match
case ETHASH_IO_MEMO_MISMATCH:
if (!ethash_mmap(ret, f)) {
goto fail_close_file;
}
break;
}
if (!ethash_compute_full_data(ret->data, full_size, light, callback)) {
goto fail_free_full_data;
}
// after the DAG has been filled then we finalize it by writting the magic number at the beginning
if (fseek(f, 0, SEEK_SET) != 0) {
goto fail_free_full_data;
}
uint64_t const magic_num = ETHASH_DAG_MAGIC_NUM;
if (fwrite(&magic_num, ETHASH_DAG_MAGIC_NUM_SIZE, 1, f) != 1) {
goto fail_free_full_data;
}
fflush(f); // make sure the magic number IS there
return ret;
fail_free_full_data:
// could check that munmap(..) == 0 but even if it did not can't really do anything here
munmap(ret->data, (size_t)full_size);
fail_close_file:
fclose(ret->file);
fail_free_full:
free(ret);
return NULL;
}
ethash_full_t ethash_full_new(ethash_light_t light, ethash_callback_t callback)
{
char strbuf[256];
if (!ethash_get_default_dirname(strbuf, 256)) {
return NULL;
}
uint64_t full_size = ethash_get_datasize(light->block_number);
ethash_h256_t seedhash = ethash_get_seedhash(light->block_number);
return ethash_full_new_internal(strbuf, seedhash, full_size, light, callback);
}
void ethash_full_delete(ethash_full_t full)
{
// could check that munmap(..) == 0 but even if it did not can't really do anything here
munmap(full->data, (size_t)full->file_size);
if (full->file) {
fclose(full->file);
}
free(full);
}
ethash_return_value_t ethash_full_compute(
ethash_full_t full,
ethash_h256_t const header_hash,
uint64_t nonce
)
{
ethash_return_value_t ret;
ret.success = true;
if (!ethash_hash(
&ret,
(node const*)full->data,
NULL,
full->file_size,
header_hash,
nonce)) {
ret.success = false;
}
return ret;
}
void const* ethash_full_dag(ethash_full_t full)
{
return full->data;
}
uint64_t ethash_full_dag_size(ethash_full_t full)
{
return full->file_size;
}