From 82dbba10d467e28e56929e2e7f3b1f04d4635da4 Mon Sep 17 00:00:00 2001 From: moneromooo-monero Date: Thu, 27 Oct 2016 23:43:44 +0100 Subject: core: dynamic fee algorithm from ArticMine The fee will vary based on the base reward and the current block size limit: fee = (R/R0) * (M0/M) * F0 R: base reward R0: reference base reward (10 monero) M: block size limit M0: minimum block size limit (60000) F0: 0.002 monero Starts applying at v4 --- src/cryptonote_core/blockchain.cpp | 52 ++++++++++++++++++++++++++++++++++++++ src/cryptonote_core/blockchain.h | 27 ++++++++++++++++++++ src/cryptonote_core/tx_pool.cpp | 6 +---- 3 files changed, 80 insertions(+), 5 deletions(-) (limited to 'src/cryptonote_core') diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp index 9ea023a4c..c92ee6c9b 100644 --- a/src/cryptonote_core/blockchain.cpp +++ b/src/cryptonote_core/blockchain.cpp @@ -46,6 +46,7 @@ #include "misc_language.h" #include "profile_tools.h" #include "file_io_utils.h" +#include "common/int-util.h" #include "common/boost_serialization_helper.h" #include "warnings.h" #include "crypto/hash.h" @@ -2708,6 +2709,57 @@ void Blockchain::check_ring_signature(const crypto::hash &tx_prefix_hash, const result = crypto::check_ring_signature(tx_prefix_hash, key_image, p_output_keys, sig.data()) ? 1 : 0; } +//------------------------------------------------------------------ +uint64_t Blockchain::get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size) +{ + if (median_block_size < CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2) + median_block_size = CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2; + + uint64_t unscaled_fee_per_kb = (DYNAMIC_FEE_PER_KB_BASE_FEE * CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2 / median_block_size); + uint64_t hi, lo = mul128(unscaled_fee_per_kb, block_reward, &hi); + static_assert(DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD % 1000000 == 0, "DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD must be divisible by 1000000"); + static_assert(DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD / 1000000 <= std::numeric_limits::max(), "DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD is too large"); + // divide in two steps, since the divisor must be 32 bits, but DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD isn't + div128_32(hi, lo, DYNAMIC_FEE_PER_KB_BASE_BLOCK_REWARD / 1000000, &hi, &lo); + div128_32(hi, lo, 1000000, &hi, &lo); + assert(hi == 0); + + return lo; +} + +//------------------------------------------------------------------ +bool Blockchain::check_fee(size_t blob_size, uint64_t fee) const +{ + const uint8_t version = get_current_hard_fork_version(); + + uint64_t fee_per_kb; + if (version < HF_VERSION_DYNAMIC_FEE) + { + fee_per_kb = FEE_PER_KB; + } + else + { + uint64_t median = m_current_block_cumul_sz_limit / 2; + uint64_t already_generated_coins = m_db->height() ? m_db->get_block_already_generated_coins(m_db->height() - 1) : 0; + uint64_t base_reward; + if (!get_block_reward(median, 1, already_generated_coins, base_reward, version)) + return false; + fee_per_kb = get_dynamic_per_kb_fee(base_reward, median); + } + LOG_PRINT_L2("Using " << print_money(fee) << "/kB fee"); + + uint64_t needed_fee = blob_size / 1024; + needed_fee += (blob_size % 1024) ? 1 : 0; + needed_fee *= fee_per_kb; + + if (fee < needed_fee) + { + LOG_PRINT_L1("transaction fee is not enough: " << print_money(fee) << ", minimum fee: " << print_money(needed_fee)); + return false; + } + return true; +} + //------------------------------------------------------------------ // This function checks to see if a tx is unlocked. unlock_time is either // a block index or a unix time. diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h index 262c2952b..3311798f0 100644 --- a/src/cryptonote_core/blockchain.h +++ b/src/cryptonote_core/blockchain.h @@ -512,6 +512,33 @@ namespace cryptonote */ bool check_tx_inputs(transaction& tx, uint64_t& pmax_used_block_height, crypto::hash& max_used_block_id, tx_verification_context &tvc, bool kept_by_block = false); + /** + * @brief get dynamic per kB fee for a given block size + * + * The dynamic fee is based on the block size in a past window, and + * the current block reward. It is expressed by kB. + * + * @param block_reward the current block reward + * @param median_block_size the median blob's size in the past window + * + * @return the per kB fee + */ + static uint64_t get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size); + + /** + * @brief validate a transaction's fee + * + * This function validates the fee is enough for the transaction. + * This is based on the size of the transaction blob, and, after a + * height threshold, on the average size of transaction in a past window + * + * @param blob_size the transaction blob's size + * @param fee the fee + * + * @return true if the fee is enough, false otherwise + */ + bool check_fee(size_t blob_size, uint64_t fee) const; + /** * @brief check that a transaction's outputs conform to current standards * diff --git a/src/cryptonote_core/tx_pool.cpp b/src/cryptonote_core/tx_pool.cpp index dba05a539..e72a592ca 100644 --- a/src/cryptonote_core/tx_pool.cpp +++ b/src/cryptonote_core/tx_pool.cpp @@ -133,12 +133,8 @@ namespace cryptonote fee = tx.rct_signatures.txnFee; } - uint64_t needed_fee = blob_size / 1024; - needed_fee += (blob_size % 1024) ? 1 : 0; - needed_fee *= FEE_PER_KB; - if (!kept_by_block && fee < needed_fee) + if (!kept_by_block && !m_blockchain.check_fee(blob_size, fee)) { - LOG_PRINT_L1("transaction fee is not enough: " << print_money(fee) << ", minimum fee: " << print_money(needed_fee)); tvc.m_verifivation_failed = true; tvc.m_fee_too_low = true; return false; -- cgit v1.2.3 From e6deb8abda0b6560c8691f376d8a86aab163dd77 Mon Sep 17 00:00:00 2001 From: moneromooo-monero Date: Fri, 28 Oct 2016 21:19:40 +0100 Subject: rpc: add a dynamic fee estimation RPC call --- src/cryptonote_core/blockchain.cpp | 30 ++++++++++++++++++++++++++++++ src/cryptonote_core/blockchain.h | 14 ++++++++++++++ 2 files changed, 44 insertions(+) (limited to 'src/cryptonote_core') diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp index c92ee6c9b..ffebcd592 100644 --- a/src/cryptonote_core/blockchain.cpp +++ b/src/cryptonote_core/blockchain.cpp @@ -2760,6 +2760,36 @@ bool Blockchain::check_fee(size_t blob_size, uint64_t fee) const return true; } +//------------------------------------------------------------------ +uint64_t Blockchain::get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks) const +{ + const uint8_t version = get_current_hard_fork_version(); + + if (version < HF_VERSION_DYNAMIC_FEE) + return FEE_PER_KB; + + if (grace_blocks >= CRYPTONOTE_REWARD_BLOCKS_WINDOW) + grace_blocks = CRYPTONOTE_REWARD_BLOCKS_WINDOW - 1; + + std::vector sz; + get_last_n_blocks_sizes(sz, CRYPTONOTE_REWARD_BLOCKS_WINDOW - grace_blocks); + for (size_t i = 0; i < grace_blocks; ++i) + sz.push_back(CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2); + + uint64_t median = epee::misc_utils::median(sz); + if(median <= CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2) + median = CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2; + + uint64_t already_generated_coins = m_db->height() ? m_db->get_block_already_generated_coins(m_db->height() - 1) : 0; + uint64_t base_reward; + if (!get_block_reward(median, 1, already_generated_coins, base_reward, version)) + return false; + + uint64_t fee = get_dynamic_per_kb_fee(base_reward, median); + LOG_PRINT_L2("Estimating " << grace_blocks << "-block fee at " << print_money(fee) << "/kB"); + return fee; +} + //------------------------------------------------------------------ // This function checks to see if a tx is unlocked. unlock_time is either // a block index or a unix time. diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h index 3311798f0..eb7a050b2 100644 --- a/src/cryptonote_core/blockchain.h +++ b/src/cryptonote_core/blockchain.h @@ -525,6 +525,20 @@ namespace cryptonote */ static uint64_t get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size); + /** + * @brief get dynamic per kB fee estimate for the next few blocks + * + * The dynamic fee is based on the block size in a past window, and + * the current block reward. It is expressed by kB. This function + * calculates an estimate for a dynamic fee which will be valid for + * the next grace_blocks + * + * @param grace_blocks number of blocks we want the fee to be valid for + * + * @return the per kB fee estimate + */ + uint64_t get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks) const; + /** * @brief validate a transaction's fee * -- cgit v1.2.3