static bool bp_block_valid_target(struct bp_block *block)
{
BIGNUM target, sha256;
BN_init(&target);
BN_init(&sha256);
u256_from_compact(&target, block->nBits);
bu256_bn(&sha256, &block->sha256);
int cmp = BN_cmp(&sha256, &target);
BN_clear_free(&target);
BN_clear_free(&sha256);
if (cmp > 0) /* sha256 > target */
return false;
return true;
}
static bool blkdb_connect(struct blkdb *db, struct blkinfo *bi,
struct blkdb_reorg *reorg_info)
{
memset(reorg_info, 0, sizeof(*reorg_info));
if (blkdb_lookup(db, &bi->hash))
return false;
bool rc = false;
BIGNUM cur_work;
BN_init(&cur_work);
u256_from_compact(&cur_work, bi->hdr.nBits);
bool best_chain = false;
/* verify genesis block matches first record */
if (bp_hashtab_size(db->blocks) == 0) {
if (!bu256_equal(&bi->hdr.sha256, &db->block0))
goto out;
/* bi->prev = NULL; */
bi->height = 0;
BN_copy(&bi->work, &cur_work);
best_chain = true;
}
/* lookup and verify previous block */
else {
struct blkinfo *prev = blkdb_lookup(db, &bi->hdr.hashPrevBlock);
if (!prev)
goto out;
bi->prev = prev;
bi->height = prev->height + 1;
if (!BN_add(&bi->work, &cur_work, &prev->work))
goto out;
if (BN_cmp(&bi->work, &db->best_chain->work) > 0)
best_chain = true;
}
/* add to block map */
bp_hashtab_put(db->blocks, &bi->hash, bi);
/* if new best chain found, update pointers */
if (best_chain) {
struct blkinfo *old_best = db->best_chain;
struct blkinfo *new_best = bi;
reorg_info->old_best = old_best;
/* likely case: new best chain has greater height */
if (!old_best) {
while (new_best) {
new_best = new_best->prev;
reorg_info->conn++;
}
} else {
while (new_best &&
(new_best->height > old_best->height)) {
new_best = new_best->prev;
reorg_info->conn++;
}
}
/* unlikely case: old best chain has greater height */
while (old_best && new_best &&
(old_best->height > new_best->height)) {
old_best = old_best->prev;
reorg_info->disconn++;
}
/* height matches, but we are still walking parallel chains */
while (old_best && new_best && (old_best != new_best)) {
new_best = new_best->prev;
reorg_info->conn++;
old_best = old_best->prev;
reorg_info->disconn++;
}
/* reorg analyzed. update database's best-chain pointer */
db->best_chain = bi;
}
rc = true;
out:
BN_clear_free(&cur_work);
return rc;
}
