/**
* Copy constructor
* @param other The other data_buffer.
*/
data_buffer(const data_buffer & other)
: m_read_ptr(0)
, file_offset_(other.file_offset_)
, file_(other.file_)
{
clear();
write_bytes(other.data(), other.size());
m_read_ptr = m_data.size() > 0 ? &m_data[0] : 0;
}
bool db_tx::read(const data_buffer & key, T & value)
{
if (m_Db == 0)
{
return false;
}
Dbt dbt_key(key.data(), static_cast<std::uint32_t> (key.size()));
Dbt dbt_value;
dbt_value.set_flags(DB_DBT_MALLOC);
auto ret = m_Db->get(m_DbTxn, &dbt_key, &dbt_value, 0);
std::memset(dbt_key.get_data(), 0, dbt_key.get_size());
if (dbt_value.get_data() == 0)
{
return false;
}
try
{
/**
* Allocate the data_buffer.
*/
data_buffer buffer(
static_cast<char *>(dbt_value.get_data()), dbt_value.get_size()
);
/**
* Decode the value from the buffer.
*/
value.decode(buffer);
}
catch (std::exception & e)
{
log_error("DB TX read failed, what = " << e.what() << ".");
return false;
}
std::memset(dbt_value.get_data(), 0, dbt_value.get_size());
free(dbt_value.get_data());
return ret == 0;
}
/**
* Copy constructor
* @param other The other data_buffer.
*/
data_buffer(const data_buffer & other)
: m_read_ptr(0)
, file_offset_(0)
{
write_bytes(other.data(), other.size());
}
bool utility::add_orphan_tx(const data_buffer & buffer)
{
/**
* Copy the buffer.
*/
auto buffer_copy = std::make_shared<data_buffer> (
buffer.data(), buffer.size()
);
/**
* Allocate the transaction.
*/
transaction tx;
/**
* Decode the transaction from the buffer.
*/
tx.decode(*buffer_copy);
/**
* Rewind the buffer.
*/
buffer_copy->rewind();
/**
* Get the hash of the transaction.
*/
auto hash_tx = tx.get_hash();
if (globals::instance().orphan_transactions().count(hash_tx) > 0)
{
return false;
}
/**
* Ignore big transactions, to avoid a send-big-orphans memory
* exhaustion attack. If a peer has a legitimate large transaction
* with a missing parent then we assume it will rebroadcast it later,
* after the parent transaction(s) have been mined or received.
* 10,000 orphans, each of which is at most 5,000 bytes big is at most
* 500 megabytes of orphans.
*/
if (buffer_copy->size() > 5000)
{
log_debug(
"Utility, add orphan tx ignoring large orphan tx size = " <<
buffer_copy->size() << ", hash = " <<
hash_tx.to_string().substr(0, 10) << "."
);
return false;
}
globals::instance().orphan_transactions()[hash_tx] = buffer_copy;
for (auto & i : tx.transactions_in())
{
globals::instance().orphan_transactions_by_previous()[
i.previous_out().get_hash()].insert(
std::make_pair(hash_tx, buffer_copy)
);
}
log_debug(
"Utility, add orphan tx stored orphan tx " <<
hash_tx.to_string().substr(0, 10) << ", orphans = " <<
globals::instance().orphan_transactions().size() << "."
);
return true;
}
