130 lines
2.9 KiB
C++
130 lines
2.9 KiB
C++
// Based on <https://github.com/grant-olson/bitmessage-powfaster>
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// fastcpu implementation.
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// TODO(Kagami): Port it to WIN32 (see bitmessage-powfaster for an
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// example).
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#define __STDC_LIMIT_MACROS
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#include <stdint.h>
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#include <string.h>
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#include <pthread.h>
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#include <arpa/inet.h>
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#include <openssl/sha.h>
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#define HASH_SIZE 64
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typedef enum {
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RESULT_NOT_READY,
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RESULT_OK,
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RESULT_OVERFLOW,
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RESULT_ERROR
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} Result;
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// Global arguments.
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size_t g_pool_size;
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uint64_t g_target;
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uint8_t* g_initial_hash;
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uint64_t g_max_nonce;
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// Shared variables for threads.
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pthread_mutex_t g_mutex;
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Result g_result = RESULT_NOT_READY;
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uint64_t g_nonce;
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inline uint64_t ntohll(uint64_t x) {
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return (
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((uint64_t)(ntohl( (unsigned int)((x << 32) >> 32) )) << 32) |
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ntohl( ((unsigned int)(x >> 32)) )
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);
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}
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// Set POW computation result in a thread-safe way.
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void set_result(Result res, uint64_t nonce) {
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pthread_mutex_lock(&g_mutex);
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if (g_result == RESULT_NOT_READY) {
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g_result = res;
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g_nonce = nonce;
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}
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pthread_mutex_unlock(&g_mutex);
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}
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void* pow_thread(void* num) {
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uint64_t i = *((size_t *)num);
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uint8_t message[HASH_SIZE+sizeof(uint64_t)];
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uint8_t digest[HASH_SIZE];
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uint64_t* be_nonce;
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uint64_t* be_trial;
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SHA512_CTX sha;
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memcpy(message+sizeof(uint64_t), g_initial_hash, HASH_SIZE);
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be_nonce = (uint64_t *)message;
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be_trial = (uint64_t *)digest;
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while (g_result == RESULT_NOT_READY) {
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// This is very unlikely to be ever happen but it's better to be
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// sure anyway.
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if (i > g_max_nonce) {
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set_result(RESULT_OVERFLOW, 0);
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return NULL;
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}
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*be_nonce = ntohll(i);
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SHA512_Init(&sha);
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SHA512_Update(&sha, message, HASH_SIZE+sizeof(uint64_t));
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SHA512_Final(digest, &sha);
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SHA512_Init(&sha);
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SHA512_Update(&sha, digest, HASH_SIZE);
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SHA512_Final(digest, &sha);
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if (ntohll(*be_trial) <= g_target) {
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set_result(RESULT_OK, i);
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return NULL;
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}
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i += g_pool_size;
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}
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return NULL;
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}
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int pow(size_t pool_size,
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uint64_t target,
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const uint8_t* initial_hash,
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uint64_t max_nonce,
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uint64_t* nonce) {
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g_pool_size = pool_size;
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g_target = target;
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g_initial_hash = (uint8_t *)initial_hash;
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g_max_nonce = max_nonce ? max_nonce : UINT64_MAX;
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pthread_mutex_init(&g_mutex, NULL);
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pthread_t threads[pool_size];
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size_t args[pool_size];
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size_t i;
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int error;
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for (i = 0; i < pool_size; i++) {
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args[i] = i;
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error = pthread_create(&threads[i], NULL, pow_thread, &args[i]);
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if (error) {
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set_result(RESULT_ERROR, 0);
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break;
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}
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}
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// Wait for only spawned threads.
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while (i--) {
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pthread_join(threads[i], NULL);
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}
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switch (g_result) {
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case RESULT_OK:
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*nonce = g_nonce;
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error = 0;
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break;
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case RESULT_OVERFLOW:
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error = -1;
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break;
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default:
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error = -2;
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}
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pthread_mutex_destroy(&g_mutex);
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return error;
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}
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