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blkmaker.c
180 lines (143 loc) · 4.69 KB
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blkmaker.c
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/*
* Copyright 2012 Luke Dashjr
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the standard MIT license. See COPYING for more details.
*/
#include <limits.h>
#include <stdbool.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <unistd.h>
#include <blkmaker.h>
#include <blktemplate.h>
static inline
void my_htole32(unsigned char *buf, uint32_t n) {
buf[0] = (n >> 0) % 256;
buf[1] = (n >> 8) % 256;
buf[2] = (n >> 16) % 256;
buf[3] = (n >> 24) % 256;
}
bool (*blkmk_sha256_impl)(void *, const void *, size_t) = NULL;
static
bool dblsha256(void *hash, const void *data, size_t datasz) {
return blkmk_sha256_impl(hash, data, datasz) && blkmk_sha256_impl(hash, hash, 32);
}
static
bool build_merkle_root(unsigned char *mrklroot_out, blktemplate_t *tmpl, unsigned char *cbtxndata, size_t cbtxndatasz) {
size_t hashcount = tmpl->txncount + 1;
unsigned char hashes[(hashcount + 1) * 32];
if (!dblsha256(&hashes[0], cbtxndata, cbtxndatasz))
return false;
for (unsigned long i = 0; i < tmpl->txncount; ++i)
if (!dblsha256(&hashes[32 * (i + 1)], tmpl->txns[i].data, tmpl->txns[i].datasz))
return false;
while (hashcount > 1)
{
if (hashcount % 2)
{
memcpy(&hashes[32 * hashcount], &hashes[32 * (hashcount - 1)], 32);
++hashcount;
}
for (size_t i = 0; i < hashcount; i += 2)
// This is where we overlap input and output, on the first pair
if (!dblsha256(&hashes[i / 2 * 32], &hashes[32 * i], 64))
return false;
hashcount /= 2;
}
memcpy(mrklroot_out, &hashes[0], 32);
return true;
}
static const int cbScriptSigLen = 4 + 1 + 36;
static
bool _blkmk_append_cb(blktemplate_t *tmpl, void *vout, const void *append, size_t appendsz) {
unsigned char *out = vout;
unsigned char *in = tmpl->cbtxn->data;
size_t insz = tmpl->cbtxn->datasz;
if (in[cbScriptSigLen] > 100 - appendsz)
return false;
int cbPostScriptSig = cbScriptSigLen + 1 + in[cbScriptSigLen];
unsigned char *outPostScriptSig = &out[cbPostScriptSig];
void *outExtranonce = (void*)outPostScriptSig;
outPostScriptSig += appendsz;
if (out != in)
{
memcpy(out, in, cbPostScriptSig+1);
memcpy(outPostScriptSig, &in[cbPostScriptSig], insz - cbPostScriptSig);
}
else
memmove(outPostScriptSig, &in[cbPostScriptSig], insz - cbPostScriptSig);
out[cbScriptSigLen] += appendsz;
memcpy(outExtranonce, append, appendsz);
return true;
}
ssize_t blkmk_append_coinbase_safe(blktemplate_t *tmpl, const void *append, size_t appendsz) {
if (!(tmpl->mutations & (BMM_CBAPPEND | BMM_CBSET)))
return -1;
size_t datasz = tmpl->cbtxn->datasz;
size_t availsz = 100 - sizeof(unsigned int) - tmpl->cbtxn->data[cbScriptSigLen];
if (appendsz > availsz)
return availsz;
void *newp = realloc(tmpl->cbtxn->data, datasz + appendsz);
if (!newp)
return -2;
tmpl->cbtxn->data = newp;
if (!_blkmk_append_cb(tmpl, newp, append, appendsz))
return -3;
tmpl->cbtxn->datasz += appendsz;
return availsz;
}
bool _blkmk_extranonce(blktemplate_t *tmpl, void *vout, unsigned int workid, size_t *offs) {
unsigned char *in = tmpl->cbtxn->data;
size_t insz = tmpl->cbtxn->datasz;
if (!workid)
{
memcpy(vout, in, insz);
*offs += insz;
return true;
}
if (!_blkmk_append_cb(tmpl, vout, &workid, sizeof(workid)))
return false;
*offs += insz + sizeof(workid);
return true;
}
size_t blkmk_get_data(blktemplate_t *tmpl, void *buf, size_t bufsz, time_t usetime, int16_t *out_expire, unsigned int *out_dataid) {
if (!(blkmk_time_left(tmpl, usetime) && blkmk_work_left(tmpl) && tmpl->cbtxn))
return 0;
if (bufsz < 76)
return 76;
unsigned char *cbuf = buf;
my_htole32(&cbuf[0], tmpl->version);
memcpy(&cbuf[4], &tmpl->prevblk, 32);
unsigned char cbtxndata[tmpl->cbtxn->datasz + sizeof(*out_dataid)];
size_t cbtxndatasz = 0;
*out_dataid = tmpl->next_dataid++;
if (!_blkmk_extranonce(tmpl, cbtxndata, *out_dataid, &cbtxndatasz))
return 0;
if (!build_merkle_root(&cbuf[36], tmpl, cbtxndata, cbtxndatasz))
return 0;
blktime_t timehdr = tmpl->curtime + difftime(usetime, tmpl->_time_rcvd);
if (timehdr > tmpl->maxtime)
timehdr = tmpl->maxtime;
my_htole32(&cbuf[68], timehdr);
memcpy(&cbuf[72], &tmpl->diffbits, 4);
// TODO: set *out_expire if provided
// TEMPORARY HACK:
memcpy(tmpl->_mrklroot, &cbuf[36], 32);
return 76;
}
blktime_diff_t blkmk_time_left(const blktemplate_t *tmpl, time_t nowtime) {
double age = difftime(nowtime, tmpl->_time_rcvd);
if (age >= tmpl->expires)
return 0;
return tmpl->expires - age;
}
unsigned long blkmk_work_left(const blktemplate_t *tmpl) {
if (!tmpl->version)
return 0;
if (!(tmpl->mutations & (BMM_CBAPPEND | BMM_CBSET)))
return 1;
return UINT_MAX - tmpl->next_dataid;
return BLKMK_UNLIMITED_WORK_COUNT;
}