From 1168e8d5d529069093aee652472fd8ca9a8c533c Mon Sep 17 00:00:00 2001 From: moneromooo-monero Date: Thu, 20 Sep 2018 13:31:45 +0000 Subject: [PATCH] cryptonote_core: warn when the block rate deviates from expectations The warning threshold is set to allow a false positive every ten days on average. --- src/cryptonote_core/blockchain.cpp | 9 +++++ src/cryptonote_core/blockchain.h | 7 ---- src/cryptonote_core/cryptonote_core.cpp | 47 +++++++++++++++++++++++++ src/cryptonote_core/cryptonote_core.h | 8 +++++ 4 files changed, 64 insertions(+), 7 deletions(-) diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp index 57c4a8133..ee57c9430 100644 --- a/src/cryptonote_core/blockchain.cpp +++ b/src/cryptonote_core/blockchain.cpp @@ -900,6 +900,15 @@ difficulty_type Blockchain::get_difficulty_for_next_block() return diff; } //------------------------------------------------------------------ +std::vector Blockchain::get_last_block_timestamps(unsigned int blocks) const +{ + std::vector timestamps(blocks); + uint64_t height = m_db->height(); + while (blocks--) + timestamps[blocks] = m_db->get_block_timestamp(height - blocks - 1); + return timestamps; +} +//------------------------------------------------------------------ // This function removes blocks from the blockchain until it gets to the // position where the blockchain switch started and then re-adds the blocks // that had been removed. diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h index 463a37b64..ab09f43ac 100644 --- a/src/cryptonote_core/blockchain.h +++ b/src/cryptonote_core/blockchain.h @@ -965,13 +965,6 @@ namespace cryptonote */ std::vector get_last_block_timestamps(unsigned int blocks) const; - /** - * @brief removes blocks from the top of the blockchain - * - * @param nblocks number of blocks to be removed - */ - void pop_blocks(uint64_t nblocks); - #ifndef IN_UNIT_TESTS private: #endif diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp index 40541ba8c..ca603f79b 100644 --- a/src/cryptonote_core/cryptonote_core.cpp +++ b/src/cryptonote_core/cryptonote_core.cpp @@ -1495,6 +1495,7 @@ namespace cryptonote m_txpool_auto_relayer.do_call(boost::bind(&core::relay_txpool_transactions, this)); m_check_updates_interval.do_call(boost::bind(&core::check_updates, this)); m_check_disk_space_interval.do_call(boost::bind(&core::check_disk_space, this)); + m_block_rate_interval.do_call(boost::bind(&core::check_block_rate, this)); m_miner.on_idle(); m_mempool.on_idle(); return true; @@ -1683,6 +1684,52 @@ namespace cryptonote return true; } //----------------------------------------------------------------------------------------------- + double factorial(unsigned int n) + { + if (n <= 1) + return 1.0; + double f = n; + while (n-- > 1) + f *= n; + return f; + } + //----------------------------------------------------------------------------------------------- + static double probability(unsigned int blocks, unsigned int expected) + { + // https://www.umass.edu/wsp/resources/poisson/#computing + return pow(expected, blocks) / (factorial(blocks) * exp(expected)); + } + //----------------------------------------------------------------------------------------------- + bool core::check_block_rate() + { + if (m_offline || m_target_blockchain_height > get_current_blockchain_height()) + { + MDEBUG("Not checking block rate, offline or syncing"); + return true; + } + + static constexpr double threshold = 1. / (864000 / DIFFICULTY_TARGET_V2); // one false positive every 10 days + + const time_t now = time(NULL); + const std::vector timestamps = m_blockchain_storage.get_last_block_timestamps(60); + + static const unsigned int seconds[] = { 5400, 1800, 600 }; + for (size_t n = 0; n < sizeof(seconds)/sizeof(seconds[0]); ++n) + { + unsigned int b = 0; + for (time_t ts: timestamps) b += ts >= now - seconds[n]; + const double p = probability(b, seconds[n] / DIFFICULTY_TARGET_V2); + MDEBUG("blocks in the last " << seconds[n] / 60 << " minutes: " << b << " (probability " << p << ")"); + if (p < threshold) + { + MWARNING("There were " << b << " blocks in the last " << seconds[n] / 60 << " minutes, there might be large hash rate changes, or we might be partitioned, cut off from the Monero network or under attack. Or it could be just sheer bad luck."); + break; // no need to look further + } + } + + return true; + } + //----------------------------------------------------------------------------------------------- void core::set_target_blockchain_height(uint64_t target_blockchain_height) { m_target_blockchain_height = target_blockchain_height; diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h index c74c244b0..799a68397 100644 --- a/src/cryptonote_core/cryptonote_core.h +++ b/src/cryptonote_core/cryptonote_core.h @@ -946,6 +946,13 @@ namespace cryptonote */ bool check_disk_space(); + /** + * @brief checks block rate, and warns if it's too slow + * + * @return true on success, false otherwise + */ + bool check_block_rate(); + bool m_test_drop_download = true; //!< whether or not to drop incoming blocks (for testing) uint64_t m_test_drop_download_height = 0; //!< height under which to drop incoming blocks, if doing so @@ -970,6 +977,7 @@ namespace cryptonote epee::math_helper::once_a_time_seconds<60*2, false> m_txpool_auto_relayer; //!< interval for checking re-relaying txpool transactions epee::math_helper::once_a_time_seconds<60*60*12, true> m_check_updates_interval; //!< interval for checking for new versions epee::math_helper::once_a_time_seconds<60*10, true> m_check_disk_space_interval; //!< interval for checking for disk space + epee::math_helper::once_a_time_seconds<90, false> m_block_rate_interval; //!< interval for checking block rate std::atomic m_starter_message_showed; //!< has the "daemon will sync now" message been shown?