Merge pull request #405

5b11a89 hardfork: most state now saved to the DB (moneromooo-monero)
0a54c3a hardfork: remove the "parts are copyright cryptonote" notices (moneromooo-monero)
e546f37 Add an RPC call and daemon command to get info on hard fork voting (moneromooo-monero)
d067131 blockchain: force a hardfork recalculation at load time (moneromooo-monero)
a717761 core: add consts where appropriate (moneromooo-monero)
8ffc508 core: moan when we think an update is needed to get latest hard fork info (moneromooo-monero)
f854984 blockchain: use the new hardfork class (moneromooo-monero)
62b1f74 New hardfork class (moneromooo-monero)
bed9a44 blockchain: add a couple missing includes (moneromooo-monero)

10 files changed, 661 insertions, 89 deletions

diff --git a/src/cryptonote_core/CMakeLists.txt b/src/cryptonote_core/CMakeLists.txt
index 6315fc4f0..7b0a5017d 100644
--- a/src/cryptonote_core/CMakeLists.txt
+++ b/src/cryptonote_core/CMakeLists.txt
@@ -37,7 +37,8 @@ set(cryptonote_core_sources
   cryptonote_format_utils.cpp
   difficulty.cpp
   miner.cpp
-  tx_pool.cpp)
+  tx_pool.cpp
+  hardfork.cpp)
 
 set(cryptonote_core_headers)
 
@@ -60,7 +61,8 @@ set(cryptonote_core_private_headers
   miner.h
   tx_extra.h
   tx_pool.h
-  verification_context.h)
+  verification_context.h
+  hardfork.h)
 
 if(PER_BLOCK_CHECKPOINT)
 	set(Blocks "blocks")
diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 09f8f8d7f..65d07dcf7 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -69,6 +69,18 @@ extern "C" void slow_hash_free_state();
 
 DISABLE_VS_WARNINGS(4267)
 
+static const struct {
+  uint8_t version;
+  uint64_t height;
+  time_t time;
+} hard_forks[] = {
+  // version 1 from the start of the blockchain
+  { 1, 1, 1341378000 },
+
+  // version 2 can start from block 1009827, setup on the 20th of september
+  { 2, 1009827, 1442763710 },
+};
+
 //------------------------------------------------------------------
 Blockchain::Blockchain(tx_memory_pool& tx_pool) :
 m_db(), m_tx_pool(tx_pool), m_timestamps_and_difficulties_height(0), m_current_block_cumul_sz_limit(0), m_is_in_checkpoint_zone(false), 
@@ -118,6 +130,11 @@ void Blockchain::serialize(archive_t & ar, const unsigned int version)
         }
     }
 
+    if (version > 12)
+    {
+        ar & *m_hardfork;
+    }
+
     LOG_PRINT_L3("Blockchain storage:" << std::endl << "m_blocks: " << m_db->height() << std::endl << "m_blocks_index: " << m_blocks_index.size() << std::endl << "m_transactions: " << m_transactions.size() << std::endl << "dummy_key_images_container: " << dummy_key_images_container.size() << std::endl << "m_alternative_chains: " << m_alternative_chains.size() << std::endl << "m_outputs: " << m_outputs.size() << std::endl << "m_invalid_blocks: " << m_invalid_blocks.size() << std::endl << "m_current_block_cumul_sz_limit: " << m_current_block_cumul_sz_limit);
 }
 //------------------------------------------------------------------
@@ -270,6 +287,11 @@ bool Blockchain::init(BlockchainDB* db, const bool testnet)
 
     m_db = db;
 
+    m_hardfork = new HardFork(*db);
+    for (size_t n = 0; n < sizeof(hard_forks) / sizeof(hard_forks[0]); ++n)
+      m_hardfork->add(hard_forks[n].version, hard_forks[n].height, hard_forks[n].time);
+    m_hardfork->init();
+
     // if the blockchain is new, add the genesis block
     // this feels kinda kludgy to do it this way, but can be looked at later.
     // TODO: add function to create and store genesis block,
@@ -416,6 +438,7 @@ bool Blockchain::deinit()
         LOG_PRINT_L0("There was an issue closing/storing the blockchain, shutting down now to prevent issues!");
     }
 
+    delete m_hardfork;
     delete m_db;
     return true;
 }
@@ -706,6 +729,8 @@ bool Blockchain::rollback_blockchain_switching(std::list<block>& original_chain,
         CHECK_AND_ASSERT_MES(r && bvc.m_added_to_main_chain, false, "PANIC! failed to add (again) block while chain switching during the rollback!");
     }
 
+    m_hardfork->reorganize_from_chain_height(rollback_height);
+
     LOG_PRINT_L1("Rollback to height " << rollback_height << " was successful.");
     if (original_chain.size())
     {
@@ -803,6 +828,8 @@ bool Blockchain::switch_to_alternative_blockchain(std::list<blocks_ext_by_hash::
         m_alternative_chains.erase(ch_ent);
     }
 
+    m_hardfork->reorganize_from_chain_height(split_height);
+
     LOG_PRINT_GREEN("REORGANIZE SUCCESS! on height: " << split_height << ", new blockchain size: " << m_db->height(), LOG_LEVEL_0);
     return true;
 }
@@ -972,12 +999,13 @@ bool Blockchain::create_block_template(block& b, const account_public_address& m
     uint64_t already_generated_coins;
 
     CRITICAL_REGION_BEGIN(m_blockchain_lock);
-    b.major_version = CURRENT_BLOCK_MAJOR_VERSION;
-    b.minor_version = CURRENT_BLOCK_MINOR_VERSION;
+    height = m_db->height();
+
+    b.major_version = m_hardfork->get_ideal_version();
+    b.minor_version = 0;
     b.prev_id = get_tail_id();
     b.timestamp = time(NULL);
 
-    height = m_db->height();
     diffic = get_difficulty_for_next_block();
     CHECK_AND_ASSERT_MES(diffic, false, "difficulty owverhead.");
 
@@ -1622,7 +1650,7 @@ bool Blockchain::get_transactions(const t_ids_container& txs_ids, t_tx_container
     return true;
 }
 //------------------------------------------------------------------
-void Blockchain::print_blockchain(uint64_t start_index, uint64_t end_index)
+void Blockchain::print_blockchain(uint64_t start_index, uint64_t end_index) const
 {
     LOG_PRINT_L3("Blockchain::" << __func__);
     std::stringstream ss;
@@ -1642,7 +1670,7 @@ void Blockchain::print_blockchain(uint64_t start_index, uint64_t end_index)
     LOG_PRINT_L0("Blockchain printed with log level 1");
 }
 //------------------------------------------------------------------
-void Blockchain::print_blockchain_index()
+void Blockchain::print_blockchain_index() const
 {
     LOG_PRINT_L3("Blockchain::" << __func__);
     std::stringstream ss;
@@ -1660,7 +1688,7 @@ void Blockchain::print_blockchain_index()
 }
 //------------------------------------------------------------------
 //TODO: remove this function and references to it
-void Blockchain::print_blockchain_outs(const std::string& file)
+void Blockchain::print_blockchain_outs(const std::string& file) const
 {
     LOG_PRINT_L3("Blockchain::" << __func__);
     return;
@@ -2245,6 +2273,13 @@ bool Blockchain::handle_block_to_main_chain(const block& bl, const crypto::hash&
     CRITICAL_REGION_LOCAL(m_blockchain_lock);
     TIME_MEASURE_START(t1);
 
+    // this is a cheap test
+    if (!m_hardfork->check(bl))
+    {
+        LOG_PRINT_L1("Block with id: " << id << std::endl << "has old version: " << bl.major_version << std::endl << "current: " << m_hardfork->get_current_version());
+        return false;
+    }
+
     if(bl.prev_id != get_tail_id())
     {
         LOG_PRINT_L1("Block with id: " << id << std::endl << "has wrong prev_id: " << bl.prev_id << std::endl << "expected: " << get_tail_id());
@@ -2521,6 +2556,9 @@ bool Blockchain::handle_block_to_main_chain(const block& bl, const crypto::hash&
 
     update_next_cumulative_size_limit();
 
+    // this will not fail since check succeeded above
+    m_hardfork->add(bl, new_height - 1);
+
     LOG_PRINT_L1("+++++ BLOCK SUCCESSFULLY ADDED" << std::endl << "id:\t" << id << std::endl << "PoW:\t" << proof_of_work << std::endl << "HEIGHT " << new_height << ", difficulty:\t" << current_diffic << std::endl << "block reward: " << print_money(fee_summary + base_reward) << "(" << print_money(base_reward) << " + " << print_money(fee_summary) << "), coinbase_blob_size: " << coinbase_blob_size << ", cumulative size: " << cumulative_block_size << ", " << block_processing_time << "(" << target_calculating_time << "/" << longhash_calculating_time << ")ms");
     if(m_show_time_stats)
     {
@@ -3054,3 +3092,13 @@ void Blockchain::set_user_options(uint64_t maxthreads, uint64_t blocks_per_sync,
     m_db_blocks_per_sync = blocks_per_sync;
     m_max_prepare_blocks_threads = maxthreads;
 }
+
+HardFork::State Blockchain::get_hard_fork_state() const
+{
+    return m_hardfork->get_state();
+}
+
+bool Blockchain::get_hard_fork_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint8_t &voting) const
+{
+    return m_hardfork->get_voting_info(version, window, votes, threshold, voting);
+}
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 57763f6ca..a248682fc 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -38,6 +38,8 @@
 #include <boost/multi_index/member.hpp>
 #include <boost/foreach.hpp>
 #include <atomic>
+#include <unordered_map>
+#include <unordered_set>
 
 #include "syncobj.h"
 #include "string_tools.h"
@@ -50,6 +52,7 @@
 #include "verification_context.h"
 #include "crypto/hash.h"
 #include "checkpoints.h"
+#include "hardfork.h"
 #include "blockchain_db/blockchain_db.h"
 
 namespace cryptonote
@@ -142,9 +145,9 @@ namespace cryptonote
     bool get_transactions(const t_ids_container& txs_ids, t_tx_container& txs, t_missed_container& missed_txs) const;
 
     //debug functions
-    void print_blockchain(uint64_t start_index, uint64_t end_index);
-    void print_blockchain_index();
-    void print_blockchain_outs(const std::string& file);
+    void print_blockchain(uint64_t start_index, uint64_t end_index) const;
+    void print_blockchain_index() const;
+    void print_blockchain_outs(const std::string& file) const;
 
     void check_against_checkpoints(const checkpoints& points, bool enforce);
     void set_enforce_dns_checkpoints(bool enforce);
@@ -156,6 +159,11 @@ namespace cryptonote
 
     void set_show_time_stats(bool stats) { m_show_time_stats = stats; }
     
+    HardFork::State get_hard_fork_state() const;
+    uint8_t get_current_hard_fork_version() const { return m_hardfork->get_current_version(); }
+    uint8_t get_ideal_hard_fork_version() const { return m_hardfork->get_ideal_version(); }
+    bool get_hard_fork_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint8_t &voting) const;
+
     BlockchainDB& get_db()
     {
       return *m_db;
@@ -225,6 +233,8 @@ namespace cryptonote
     std::atomic<bool> m_is_blockchain_storing;
     bool m_enforce_dns_checkpoints;
 
+    HardFork *m_hardfork;
+
     template<class visitor_t>
     inline bool scan_outputkeys_for_indexes(const txin_to_key& tx_in_to_key, visitor_t &vis, const crypto::hash &tx_prefix_hash, uint64_t* pmax_related_block_height = NULL) const;
     bool check_tx_input(const txin_to_key& txin, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig, std::vector<crypto::public_key> &output_keys, uint64_t* pmax_related_block_height);
@@ -266,10 +276,10 @@ namespace cryptonote
   /*                                                                      */
   /************************************************************************/
 
-  #define CURRENT_BLOCKCHAIN_STORAGE_ARCHIVE_VER    12
+  #define CURRENT_BLOCKCHAIN_ARCHIVE_VER    13
 
   //------------------------------------------------------------------
 
 }  // namespace cryptonote
 
-BOOST_CLASS_VERSION(cryptonote::Blockchain, CURRENT_BLOCKCHAIN_STORAGE_ARCHIVE_VER)
+BOOST_CLASS_VERSION(cryptonote::Blockchain, CURRENT_BLOCKCHAIN_ARCHIVE_VER)
diff --git a/src/cryptonote_core/blockchain_storage.cpp b/src/cryptonote_core/blockchain_storage.cpp
index ee4263687..4a4d348ba 100644
--- a/src/cryptonote_core/blockchain_storage.cpp
+++ b/src/cryptonote_core/blockchain_storage.cpp
@@ -1178,7 +1178,7 @@ double blockchain_storage::get_avg_block_size( size_t count) const
 		return average;
 }
 //------------------------------------------------------------------
-void blockchain_storage::print_blockchain(uint64_t start_index, uint64_t end_index)
+void blockchain_storage::print_blockchain(uint64_t start_index, uint64_t end_index) const
 {
   std::stringstream ss;
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
@@ -1198,7 +1198,7 @@ void blockchain_storage::print_blockchain(uint64_t start_index, uint64_t end_ind
   LOG_PRINT_L0("Blockchain printed with log level 1");
 }
 //------------------------------------------------------------------
-void blockchain_storage::print_blockchain_index()
+void blockchain_storage::print_blockchain_index() const
 {
   std::stringstream ss;
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
@@ -1208,7 +1208,7 @@ void blockchain_storage::print_blockchain_index()
   LOG_PRINT_L0("Current blockchain index:" << ENDL << ss.str());
 }
 //------------------------------------------------------------------
-void blockchain_storage::print_blockchain_outs(const std::string& file)
+void blockchain_storage::print_blockchain_outs(const std::string& file) const
 {
   std::stringstream ss;
   CRITICAL_REGION_LOCAL(m_blockchain_lock);
diff --git a/src/cryptonote_core/blockchain_storage.h b/src/cryptonote_core/blockchain_storage.h
index aeeef31b6..2a4cfcd49 100644
--- a/src/cryptonote_core/blockchain_storage.h
+++ b/src/cryptonote_core/blockchain_storage.h
@@ -173,9 +173,9 @@ namespace cryptonote
       return true;
     }
     //debug functions
-    void print_blockchain(uint64_t start_index, uint64_t end_index);
-    void print_blockchain_index();
-    void print_blockchain_outs(const std::string& file);
+    void print_blockchain(uint64_t start_index, uint64_t end_index) const;
+    void print_blockchain_index() const;
+    void print_blockchain_outs(const std::string& file) const;
     void check_against_checkpoints(const checkpoints& points, bool enforce);
     bool update_checkpoints(const std::string& file_path, bool check_dns);
     void set_enforce_dns_checkpoints(bool enforce_checkpoints);
diff --git a/src/cryptonote_core/cryptonote_basic.h b/src/cryptonote_core/cryptonote_basic.h
index 07745bf0d..d3db50068 100644
--- a/src/cryptonote_core/cryptonote_basic.h
+++ b/src/cryptonote_core/cryptonote_basic.h
@@ -182,7 +182,6 @@ namespace cryptonote
       FIELD(extra)
     END_SERIALIZE()
 
-
   protected:
     transaction_prefix(){}
   };
@@ -278,7 +277,7 @@ namespace cryptonote
   /************************************************************************/
   struct block_header
   {
-    uint8_t major_version;
+    uint8_t major_version;  // now used as a voting mechanism, rather than how this particular block is built
     uint8_t minor_version;
     uint64_t timestamp;
     crypto::hash  prev_id;
@@ -286,7 +285,6 @@ namespace cryptonote
 
     BEGIN_SERIALIZE()
       VARINT_FIELD(major_version)
-      if(major_version > CURRENT_BLOCK_MAJOR_VERSION) return false;
       VARINT_FIELD(minor_version)
       VARINT_FIELD(timestamp)
       FIELD(prev_id)
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 4d90eec1e..4ade50cde 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -168,37 +168,37 @@ namespace cryptonote
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  uint64_t core::get_current_blockchain_height()
+  uint64_t core::get_current_blockchain_height() const
   {
     return m_blockchain_storage.get_current_blockchain_height();
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_blockchain_top(uint64_t& height, crypto::hash& top_id)
+  bool core::get_blockchain_top(uint64_t& height, crypto::hash& top_id) const
   {
     top_id = m_blockchain_storage.get_tail_id(height);
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks, std::list<transaction>& txs)
+  bool core::get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks, std::list<transaction>& txs) const
   {
     return m_blockchain_storage.get_blocks(start_offset, count, blocks, txs);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks)
+  bool core::get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks) const
   {
     return m_blockchain_storage.get_blocks(start_offset, count, blocks);
   }  //-----------------------------------------------------------------------------------------------
-  bool core::get_transactions(const std::vector<crypto::hash>& txs_ids, std::list<transaction>& txs, std::list<crypto::hash>& missed_txs)
+  bool core::get_transactions(const std::vector<crypto::hash>& txs_ids, std::list<transaction>& txs, std::list<crypto::hash>& missed_txs) const
   {
     return m_blockchain_storage.get_transactions(txs_ids, txs, missed_txs);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_alternative_blocks(std::list<block>& blocks)
+  bool core::get_alternative_blocks(std::list<block>& blocks) const
   {
     return m_blockchain_storage.get_alternative_blocks(blocks);
   }
   //-----------------------------------------------------------------------------------------------
-  size_t core::get_alternative_blocks_count()
+  size_t core::get_alternative_blocks_count() const
   {
     return m_blockchain_storage.get_alternative_blocks_count();
   }
@@ -385,12 +385,12 @@ namespace cryptonote
 	  m_test_drop_download_height = height;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_test_drop_download()
+  bool core::get_test_drop_download() const
   {
 	  return m_test_drop_download;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_test_drop_download_height()
+  bool core::get_test_drop_download_height() const
   {
 	  if (m_test_drop_download_height == 0)
 		return true;
@@ -451,7 +451,7 @@ namespace cryptonote
     return r;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_stat_info(core_stat_info& st_inf)
+  bool core::get_stat_info(core_stat_info& st_inf) const
   {
     st_inf.mining_speed = m_miner.get_speed();
     st_inf.alternative_blocks = m_blockchain_storage.get_alternative_blocks_count();
@@ -462,7 +462,7 @@ namespace cryptonote
   }
 
   //-----------------------------------------------------------------------------------------------
-  bool core::check_tx_semantic(const transaction& tx, bool keeped_by_block)
+  bool core::check_tx_semantic(const transaction& tx, bool keeped_by_block) const
   {
     if(!tx.vin.size())
     {
@@ -515,12 +515,12 @@ namespace cryptonote
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::is_key_image_spent(const crypto::key_image &key_image)
+  bool core::is_key_image_spent(const crypto::key_image &key_image) const
   {
     return m_blockchain_storage.have_tx_keyimg_as_spent(key_image);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::are_key_images_spent(const std::vector<crypto::key_image>& key_im, std::vector<bool> &spent)
+  bool core::are_key_images_spent(const std::vector<crypto::key_image>& key_im, std::vector<bool> &spent) const
   {
     spent.clear();
     BOOST_FOREACH(auto& ki, key_im)
@@ -530,7 +530,7 @@ namespace cryptonote
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::check_tx_inputs_keyimages_diff(const transaction& tx)
+  bool core::check_tx_inputs_keyimages_diff(const transaction& tx) const
   {
     std::unordered_set<crypto::key_image> ki;
     BOOST_FOREACH(const auto& in, tx.vin)
@@ -551,7 +551,7 @@ namespace cryptonote
     return add_new_tx(tx, tx_hash, tx_prefix_hash, bl.size(), tvc, keeped_by_block);
   }
   //-----------------------------------------------------------------------------------------------
-  size_t core::get_blockchain_total_transactions()
+  size_t core::get_blockchain_total_transactions() const
   {
     return m_blockchain_storage.get_total_transactions();
   }
@@ -583,22 +583,22 @@ namespace cryptonote
     return m_blockchain_storage.create_block_template(b, adr, diffic, height, ex_nonce);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::find_blockchain_supplement(const std::list<crypto::hash>& qblock_ids, NOTIFY_RESPONSE_CHAIN_ENTRY::request& resp)
+  bool core::find_blockchain_supplement(const std::list<crypto::hash>& qblock_ids, NOTIFY_RESPONSE_CHAIN_ENTRY::request& resp) const
   {
     return m_blockchain_storage.find_blockchain_supplement(qblock_ids, resp);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::find_blockchain_supplement(const uint64_t req_start_block, const std::list<crypto::hash>& qblock_ids, std::list<std::pair<block, std::list<transaction> > >& blocks, uint64_t& total_height, uint64_t& start_height, size_t max_count)
+  bool core::find_blockchain_supplement(const uint64_t req_start_block, const std::list<crypto::hash>& qblock_ids, std::list<std::pair<block, std::list<transaction> > >& blocks, uint64_t& total_height, uint64_t& start_height, size_t max_count) const
   {
     return m_blockchain_storage.find_blockchain_supplement(req_start_block, qblock_ids, blocks, total_height, start_height, max_count);
   }
   //-----------------------------------------------------------------------------------------------
-  void core::print_blockchain(uint64_t start_index, uint64_t end_index)
+  void core::print_blockchain(uint64_t start_index, uint64_t end_index) const
   {
     m_blockchain_storage.print_blockchain(start_index, end_index);
   }
   //-----------------------------------------------------------------------------------------------
-  void core::print_blockchain_index()
+  void core::print_blockchain_index() const
   {
     m_blockchain_storage.print_blockchain_index();
   }
@@ -608,12 +608,12 @@ namespace cryptonote
     m_blockchain_storage.print_blockchain_outs(file);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_random_outs_for_amounts(const COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::request& req, COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::response& res)
+  bool core::get_random_outs_for_amounts(const COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::request& req, COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::response& res) const
   {
     return m_blockchain_storage.get_random_outs_for_amounts(req, res);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs)
+  bool core::get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const
   {
     return m_blockchain_storage.get_tx_outputs_gindexs(tx_id, indexs);
   }
@@ -728,7 +728,7 @@ namespace cryptonote
   //-----------------------------------------------------------------------------------------------
   // Used by the RPC server to check the size of an incoming
   // block_blob
-  bool core::check_incoming_block_size(const blobdata& block_blob)
+  bool core::check_incoming_block_size(const blobdata& block_blob) const
   {
     if(block_blob.size() > get_max_block_size())
     {
@@ -738,32 +738,32 @@ namespace cryptonote
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  crypto::hash core::get_tail_id()
+  crypto::hash core::get_tail_id() const
   {
     return m_blockchain_storage.get_tail_id();
   }
   //-----------------------------------------------------------------------------------------------
-  size_t core::get_pool_transactions_count()
+  size_t core::get_pool_transactions_count() const
   {
     return m_mempool.get_transactions_count();
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::have_block(const crypto::hash& id)
+  bool core::have_block(const crypto::hash& id) const
   {
     return m_blockchain_storage.have_block(id);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::parse_tx_from_blob(transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash, const blobdata& blob)
+  bool core::parse_tx_from_blob(transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash, const blobdata& blob) const
   {
     return parse_and_validate_tx_from_blob(blob, tx, tx_hash, tx_prefix_hash);
   }
   //-----------------------------------------------------------------------------------------------
-    bool core::check_tx_syntax(const transaction& tx)
+  bool core::check_tx_syntax(const transaction& tx) const
   {
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_pool_transactions(std::list<transaction>& txs)
+  bool core::get_pool_transactions(std::list<transaction>& txs) const
   {
     m_mempool.get_transactions(txs);
     return true;
@@ -774,7 +774,7 @@ namespace cryptonote
     return m_mempool.get_transactions_and_spent_keys_info(tx_infos, key_image_infos);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_short_chain_history(std::list<crypto::hash>& ids)
+  bool core::get_short_chain_history(std::list<crypto::hash>& ids) const
   {
     return m_blockchain_storage.get_short_chain_history(ids);
   }
@@ -784,12 +784,12 @@ namespace cryptonote
     return m_blockchain_storage.handle_get_objects(arg, rsp);
   }
   //-----------------------------------------------------------------------------------------------
-  crypto::hash core::get_block_id_by_height(uint64_t height)
+  crypto::hash core::get_block_id_by_height(uint64_t height) const
   {
     return m_blockchain_storage.get_block_id_by_height(height);
   }
   //-----------------------------------------------------------------------------------------------
-  bool core::get_block_by_hash(const crypto::hash &h, block &blk)
+  bool core::get_block_by_hash(const crypto::hash &h, block &blk) const
   {
     return m_blockchain_storage.get_block_by_hash(h, blk);
   }
@@ -798,7 +798,7 @@ namespace cryptonote
   //  m_blockchain_storage.get_all_known_block_ids(main, alt, invalid);
   //}
   //-----------------------------------------------------------------------------------------------
-  std::string core::print_pool(bool short_format)
+  std::string core::print_pool(bool short_format) const
   {
     return m_mempool.print_pool(short_format);
   }
@@ -830,11 +830,37 @@ namespace cryptonote
 #else
     m_store_blockchain_interval.do_call(boost::bind(&blockchain_storage::store_blockchain, &m_blockchain_storage));
 #endif
+    m_fork_moaner.do_call(boost::bind(&core::check_fork_time, this));
     m_miner.on_idle();
     m_mempool.on_idle();
     return true;
   }
   //-----------------------------------------------------------------------------------------------
+  bool core::check_fork_time()
+  {
+#if BLOCKCHAIN_DB == DB_LMDB
+    HardFork::State state = m_blockchain_storage.get_hard_fork_state();
+    switch (state) {
+      case HardFork::LikelyForked:
+        LOG_PRINT_L0(ENDL
+          << "**********************************************************************" << ENDL
+          << "Last scheduled hard fork is too far in the past." << ENDL
+          << "We are most likely forked from the network. Daemon update needed now." << ENDL
+          << "**********************************************************************" << ENDL);
+        break;
+      case HardFork::UpdateNeeded:
+        LOG_PRINT_L0(ENDL
+          << "**********************************************************************" << ENDL
+          << "Last scheduled hard fork time shows a daemon update is needed now." << ENDL
+          << "**********************************************************************" << ENDL);
+        break;
+      default:
+        break;
+    }
+#endif
+    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 d700b3b47..634340a3f 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -69,7 +69,7 @@ namespace cryptonote
      bool prepare_handle_incoming_blocks(const std::list<block_complete_entry>  &blocks);
      bool cleanup_handle_incoming_blocks(bool force_sync = false);
      	     	
-     bool check_incoming_block_size(const blobdata& block_blob);
+     bool check_incoming_block_size(const blobdata& block_blob) const;
      i_cryptonote_protocol* get_protocol(){return m_pprotocol;}
 
      //-------------------- i_miner_handler -----------------------
@@ -78,6 +78,7 @@ namespace cryptonote
 
 
      miner& get_miner(){return m_miner;}
+     const miner& get_miner()const{return m_miner;}
      static void init_options(boost::program_options::options_description& desc);
      bool init(const boost::program_options::variables_map& vm);
      bool set_genesis_block(const block& b);
@@ -86,55 +87,57 @@ namespace cryptonote
      static bool get_fast_exit();
      void test_drop_download();
      void test_drop_download_height(uint64_t height);
-     bool get_test_drop_download();
-     bool get_test_drop_download_height();
-     uint64_t get_current_blockchain_height();
-     bool get_blockchain_top(uint64_t& heeight, crypto::hash& top_id);
-     bool get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks, std::list<transaction>& txs);
-     bool get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks);
+     bool get_test_drop_download() const;
+     bool get_test_drop_download_height() const;
+     uint64_t get_current_blockchain_height() const;
+     bool get_blockchain_top(uint64_t& heeight, crypto::hash& top_id) const;
+     bool get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks, std::list<transaction>& txs) const;
+     bool get_blocks(uint64_t start_offset, size_t count, std::list<block>& blocks) const;
      template<class t_ids_container, class t_blocks_container, class t_missed_container>
-     bool get_blocks(const t_ids_container& block_ids, t_blocks_container& blocks, t_missed_container& missed_bs)
+     bool get_blocks(const t_ids_container& block_ids, t_blocks_container& blocks, t_missed_container& missed_bs) const
      {
        return m_blockchain_storage.get_blocks(block_ids, blocks, missed_bs);
      }
-     crypto::hash get_block_id_by_height(uint64_t height);
-     bool get_transactions(const std::vector<crypto::hash>& txs_ids, std::list<transaction>& txs, std::list<crypto::hash>& missed_txs);
-     bool get_block_by_hash(const crypto::hash &h, block &blk);
+     crypto::hash get_block_id_by_height(uint64_t height) const;
+     bool get_transactions(const std::vector<crypto::hash>& txs_ids, std::list<transaction>& txs, std::list<crypto::hash>& missed_txs) const;
+     bool get_block_by_hash(const crypto::hash &h, block &blk) const;
      //void get_all_known_block_ids(std::list<crypto::hash> &main, std::list<crypto::hash> &alt, std::list<crypto::hash> &invalid);
 
-     bool get_alternative_blocks(std::list<block>& blocks);
-     size_t get_alternative_blocks_count();
+     bool get_alternative_blocks(std::list<block>& blocks) const;
+     size_t get_alternative_blocks_count() const;
 
      void set_cryptonote_protocol(i_cryptonote_protocol* pprotocol);
      void set_checkpoints(checkpoints&& chk_pts);
      void set_checkpoints_file_path(const std::string& path);
      void set_enforce_dns_checkpoints(bool enforce_dns);
 
-     bool get_pool_transactions(std::list<transaction>& txs);
+     bool get_pool_transactions(std::list<transaction>& txs) const;
      bool get_pool_transactions_and_spent_keys_info(std::vector<tx_info>& tx_infos, std::vector<spent_key_image_info>& key_image_infos) const;
-     size_t get_pool_transactions_count();
-     size_t get_blockchain_total_transactions();
+     size_t get_pool_transactions_count() const;
+     size_t get_blockchain_total_transactions() const;
      //bool get_outs(uint64_t amount, std::list<crypto::public_key>& pkeys);
-     bool have_block(const crypto::hash& id);
-     bool get_short_chain_history(std::list<crypto::hash>& ids);
-     bool find_blockchain_supplement(const std::list<crypto::hash>& qblock_ids, NOTIFY_RESPONSE_CHAIN_ENTRY::request& resp);
-     bool find_blockchain_supplement(const uint64_t req_start_block, const std::list<crypto::hash>& qblock_ids, std::list<std::pair<block, std::list<transaction> > >& blocks, uint64_t& total_height, uint64_t& start_height, size_t max_count);
-     bool get_stat_info(core_stat_info& st_inf);
+     bool have_block(const crypto::hash& id) const;
+     bool get_short_chain_history(std::list<crypto::hash>& ids) const;
+     bool find_blockchain_supplement(const std::list<crypto::hash>& qblock_ids, NOTIFY_RESPONSE_CHAIN_ENTRY::request& resp) const;
+     bool find_blockchain_supplement(const uint64_t req_start_block, const std::list<crypto::hash>& qblock_ids, std::list<std::pair<block, std::list<transaction> > >& blocks, uint64_t& total_height, uint64_t& start_height, size_t max_count) const;
+     bool get_stat_info(core_stat_info& st_inf) const;
      //bool get_backward_blocks_sizes(uint64_t from_height, std::vector<size_t>& sizes, size_t count);
-     bool get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs);
-     crypto::hash get_tail_id();
-     bool get_random_outs_for_amounts(const COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::request& req, COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::response& res);
+     bool get_tx_outputs_gindexs(const crypto::hash& tx_id, std::vector<uint64_t>& indexs) const;
+     crypto::hash get_tail_id() const;
+     bool get_random_outs_for_amounts(const COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::request& req, COMMAND_RPC_GET_RANDOM_OUTPUTS_FOR_AMOUNTS::response& res) const;
      void pause_mine();
      void resume_mine();
 #if BLOCKCHAIN_DB == DB_LMDB
      Blockchain& get_blockchain_storage(){return m_blockchain_storage;}
+     const Blockchain& get_blockchain_storage()const{return m_blockchain_storage;}
 #else
      blockchain_storage& get_blockchain_storage(){return m_blockchain_storage;}
+     const blockchain_storage& get_blockchain_storage()const{return m_blockchain_storage;}
 #endif
      //debug functions
-     void print_blockchain(uint64_t start_index, uint64_t end_index);
-     void print_blockchain_index();
-     std::string print_pool(bool short_format);
+     void print_blockchain(uint64_t start_index, uint64_t end_index) const;
+     void print_blockchain_index() const;
+     std::string print_pool(bool short_format) const;
      void print_blockchain_outs(const std::string& file);
      void on_synchronized();
 
@@ -145,28 +148,29 @@ namespace cryptonote
 
      void stop();
 
-     bool is_key_image_spent(const crypto::key_image& key_im);
-     bool are_key_images_spent(const std::vector<crypto::key_image>& key_im, std::vector<bool> &spent);
+     bool is_key_image_spent(const crypto::key_image& key_im) const;
+     bool are_key_images_spent(const std::vector<crypto::key_image>& key_im, std::vector<bool> &spent) const;
 
    private:
      bool add_new_tx(const transaction& tx, const crypto::hash& tx_hash, const crypto::hash& tx_prefix_hash, size_t blob_size, tx_verification_context& tvc, bool keeped_by_block);
      bool add_new_tx(const transaction& tx, tx_verification_context& tvc, bool keeped_by_block);
      bool add_new_block(const block& b, block_verification_context& bvc);
      bool load_state_data();
-     bool parse_tx_from_blob(transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash, const blobdata& blob);
+     bool parse_tx_from_blob(transaction& tx, crypto::hash& tx_hash, crypto::hash& tx_prefix_hash, const blobdata& blob) const;
 
-     bool check_tx_syntax(const transaction& tx);
+     bool check_tx_syntax(const transaction& tx) const;
      //check correct values, amounts and all lightweight checks not related with database
-     bool check_tx_semantic(const transaction& tx, bool keeped_by_block);
+     bool check_tx_semantic(const transaction& tx, bool keeped_by_block) const;
      //check if tx already in memory pool or in main blockchain
 
-     bool check_tx_ring_signature(const txin_to_key& tx, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig);
-     bool is_tx_spendtime_unlocked(uint64_t unlock_time);
+     bool check_tx_ring_signature(const txin_to_key& tx, const crypto::hash& tx_prefix_hash, const std::vector<crypto::signature>& sig) const;
+     bool is_tx_spendtime_unlocked(uint64_t unlock_time) const;
      bool update_miner_block_template();
      bool handle_command_line(const boost::program_options::variables_map& vm);
      bool on_update_blocktemplate_interval();
-     bool check_tx_inputs_keyimages_diff(const transaction& tx);
+     bool check_tx_inputs_keyimages_diff(const transaction& tx) const;
      void graceful_exit();
+     bool check_fork_time();
      static std::atomic<bool> m_fast_exit;
      bool m_test_drop_download = true;
 	 uint64_t m_test_drop_download_height = 0;
@@ -185,6 +189,7 @@ namespace cryptonote
      std::string m_config_folder;
      cryptonote_protocol_stub m_protocol_stub;
      epee::math_helper::once_a_time_seconds<60*60*12, false> m_store_blockchain_interval;
+     epee::math_helper::once_a_time_seconds<60*60*2, false> m_fork_moaner;
      friend class tx_validate_inputs;
      std::atomic<bool> m_starter_message_showed;
 
diff --git a/src/cryptonote_core/hardfork.cpp b/src/cryptonote_core/hardfork.cpp
new file mode 100644
index 000000000..d2e95b58e
--- /dev/null
+++ b/src/cryptonote_core/hardfork.cpp
@@ -0,0 +1,267 @@
+// Copyright (c) 2015, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <algorithm>
+#include <cstdio>
+
+#include "cryptonote_core/cryptonote_basic.h"
+#include "blockchain_db/blockchain_db.h"
+#include "hardfork.h"
+
+using namespace cryptonote;
+
+HardFork::HardFork(cryptonote::BlockchainDB &db, uint8_t original_version, time_t forked_time, time_t update_time, uint64_t window_size, int threshold_percent):
+  db(db),
+  original_version(original_version),
+  forked_time(forked_time),
+  update_time(update_time),
+  window_size(window_size),
+  threshold_percent(threshold_percent)
+{
+}
+
+bool HardFork::add(uint8_t version, uint64_t height, time_t time)
+{
+  CRITICAL_REGION_LOCAL(lock);
+
+  // add in order
+  if (version == 0)
+    return false;
+  if (!heights.empty()) {
+    if (version <= heights.back().version)
+      return false;
+    if (height <= heights.back().height)
+      return false;
+    if (time <= heights.back().time)
+      return false;
+  }
+  heights.push_back({version: version, height: height, time: time});
+  return true;
+}
+
+uint8_t HardFork::get_effective_version(const cryptonote::block &block) const
+{
+  uint8_t version = block.major_version;
+  if (!heights.empty()) {
+    uint8_t max_version = heights.back().version;
+    if (version > max_version)
+      version = max_version;
+  }
+  return version;
+}
+
+bool HardFork::do_check(const cryptonote::block &block) const
+{
+  return block.major_version >= heights[current_fork_index].version;
+}
+
+bool HardFork::check(const cryptonote::block &block) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  return do_check(block);
+}
+
+bool HardFork::add(const cryptonote::block &block, uint64_t height)
+{
+  CRITICAL_REGION_LOCAL(lock);
+
+  if (!do_check(block))
+    return false;
+
+  const uint8_t version = get_effective_version(block);
+
+  while (versions.size() >= window_size) {
+    const uint8_t old_version = versions.front();
+    last_versions[old_version]--;
+    assert(last_versions[old_version] >= 0);
+    versions.pop_front();
+  }
+
+  last_versions[version]++;
+  versions.push_back(version);
+
+  uint8_t voted = get_voted_fork_index(height);
+  if (voted > current_fork_index) {
+    for (int v = heights[current_fork_index].version + 1; v <= heights[voted].version; ++v) {
+      db.set_hard_fork_starting_height(v, height);
+    }
+    current_fork_index = voted;
+  }
+
+  db.set_hard_fork_version(height, heights[current_fork_index].version);
+
+  return true;
+}
+
+void HardFork::init()
+{
+  CRITICAL_REGION_LOCAL(lock);
+  versions.clear();
+  for (size_t n = 0; n < 256; ++n)
+    last_versions[n] = 0;
+  current_fork_index = 0;
+  vote_threshold = (uint32_t)ceilf(window_size * threshold_percent / 100.0f);
+
+  // restore state from DB
+  uint64_t height = db.height();
+  if (height > window_size)
+    height -= window_size;
+  else
+    height = 1;
+
+  bool populate = db.get_hard_fork_starting_height(original_version) == std::numeric_limits<uint64_t>::max();
+  if (populate) {
+    LOG_PRINT_L0("The DB has no hard fork info, reparsing from start");
+    height = 1;
+  }
+  LOG_PRINT_L1("reorganizing from " << height);
+  reorganize_from_chain_height(height);
+  if (populate) {
+    // reorg will not touch the genesis block, use this as a flag for populating done
+    db.set_hard_fork_version(0, original_version);
+    db.set_hard_fork_starting_height(original_version, 0);
+  }
+  LOG_PRINT_L1("reorganization done");
+}
+
+bool HardFork::reorganize_from_block_height(uint64_t height)
+{
+  CRITICAL_REGION_LOCAL(lock);
+  if (height >= db.height())
+    return false;
+
+  versions.clear();
+
+  for (size_t n = 0; n < 256; ++n)
+    last_versions[n] = 0;
+  const uint64_t rescan_height = height >= (window_size - 1) ? height - (window_size - 1) : 0;
+  const uint8_t start_version = height == 0 ? original_version : db.get_hard_fork_version(height);
+  while (heights[current_fork_index].version > start_version) {
+    db.set_hard_fork_starting_height(heights[current_fork_index].version, std::numeric_limits<uint64_t>::max());
+    --current_fork_index;
+  }
+  for (uint64_t h = rescan_height; h <= height; ++h) {
+    cryptonote::block b = db.get_block_from_height(h);
+    const uint8_t v = get_effective_version(b);
+    last_versions[v]++;
+    versions.push_back(v);
+  }
+  const uint64_t bc_height = db.height();
+  for (uint64_t h = height + 1; h < bc_height; ++h) {
+    add(db.get_block_from_height(h), h);
+  }
+
+  return true;
+}
+
+bool HardFork::reorganize_from_chain_height(uint64_t height)
+{
+  if (height == 0)
+    return false;
+  return reorganize_from_block_height(height - 1);
+}
+
+int HardFork::get_voted_fork_index(uint64_t height) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  uint32_t accumulated_votes = 0;
+  for (unsigned int n = heights.size() - 1; n > current_fork_index; --n) {
+    uint8_t v = heights[n].version;
+    accumulated_votes += last_versions[v];
+    if (height >= heights[n].height && accumulated_votes >= vote_threshold) {
+      return n;
+    }
+  }
+  return current_fork_index;
+}
+
+HardFork::State HardFork::get_state(time_t t) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+
+  // no hard forks setup yet
+  if (heights.size() <= 1)
+    return Ready;
+
+  time_t t_last_fork = heights.back().time;
+  if (t >= t_last_fork + forked_time)
+    return LikelyForked;
+  if (t >= t_last_fork + update_time)
+    return UpdateNeeded;
+  return Ready;
+}
+
+HardFork::State HardFork::get_state() const
+{
+  return get_state(time(NULL));
+}
+
+uint8_t HardFork::get(uint64_t height) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  if (height > db.height()) {
+    assert(false);
+    return 255;
+  }
+  return db.get_hard_fork_version(height);
+}
+
+uint64_t HardFork::get_start_height(uint8_t version) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  return db.get_hard_fork_starting_height(version);
+}
+
+uint8_t HardFork::get_current_version() const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  return heights[current_fork_index].version;
+}
+
+uint8_t HardFork::get_ideal_version() const
+{
+  CRITICAL_REGION_LOCAL(lock);
+  return heights.back().version;
+}
+
+bool HardFork::get_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint8_t &voting) const
+{
+  CRITICAL_REGION_LOCAL(lock);
+
+  const uint8_t current_version = heights[current_fork_index].version;
+  const bool enabled = current_version >= version;
+  window = versions.size();
+  votes = 0;
+  for (size_t n = version; n < 256; ++n)
+      votes += last_versions[n];
+  threshold = vote_threshold;
+  assert((votes >= threshold) == enabled);
+  voting = heights.back().version;
+  return enabled;
+}
+
diff --git a/src/cryptonote_core/hardfork.h b/src/cryptonote_core/hardfork.h
new file mode 100644
index 000000000..bdac87f2c
--- /dev/null
+++ b/src/cryptonote_core/hardfork.h
@@ -0,0 +1,216 @@
+// Copyright (c) 2015, The Monero Project
+// 
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without modification, are
+// permitted provided that the following conditions are met:
+// 
+// 1. Redistributions of source code must retain the above copyright notice, this list of
+//    conditions and the following disclaimer.
+// 
+// 2. Redistributions in binary form must reproduce the above copyright notice, this list
+//    of conditions and the following disclaimer in the documentation and/or other
+//    materials provided with the distribution.
+// 
+// 3. Neither the name of the copyright holder nor the names of its contributors may be
+//    used to endorse or promote products derived from this software without specific
+//    prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
+// EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+// MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL
+// THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+// PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+// STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF
+// THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#pragma once
+
+#include "syncobj.h"
+#include "cryptonote_core/cryptonote_basic.h"
+
+namespace cryptonote
+{
+  class BlockchainDB;
+
+  class HardFork
+  {
+  public:
+    typedef enum {
+      LikelyForked,
+      UpdateNeeded,
+      Ready,
+    } State;
+
+    static const time_t DEFAULT_FORKED_TIME = 31557600; // a year in seconds
+    static const time_t DEFAULT_UPDATE_TIME = 31557600 / 2;
+    static const uint64_t DEFAULT_WINDOW_SIZE = 50; // supermajority window check length
+    static const int DEFAULT_THRESHOLD_PERCENT = 80;
+
+    /**
+     * @brief creates a new HardFork object
+     *
+     * @param original_version the block version for blocks 0 through to the first fork
+     * @param forked_time the time in seconds before thinking we're forked
+     * @param update_time the time in seconds before thinking we need to update
+     * @param window_size the size of the window in blocks to consider for version voting
+     * @param threshold_percent the size of the majority in percents
+     */
+    HardFork(cryptonote::BlockchainDB &db, uint8_t original_version = 1, time_t forked_time = DEFAULT_FORKED_TIME, time_t update_time = DEFAULT_UPDATE_TIME, uint64_t window_size = DEFAULT_WINDOW_SIZE, int threshold_percent = DEFAULT_THRESHOLD_PERCENT);
+
+    /**
+     * @brief add a new hardfork height
+     *
+     * returns true if no error, false otherwise
+     *
+     * @param version the major block version for the fork
+     * @param height The height the hardfork takes effect
+     * @param time Approximate time of the hardfork (seconds since epoch)
+     */
+    bool add(uint8_t version, uint64_t height, time_t time);
+
+    /**
+     * @brief initialize the object
+     *
+     * Must be done after adding all the required hardforks via add above
+     */
+    void init();
+
+    /**
+     * @brief check whether a new block would be accepted
+     *
+     * returns true if the block is accepted, false otherwise
+     *
+     * @param block the new block
+     *
+     * This check is made by add. It is exposed publicly to allow
+     * the caller to inexpensively check whether a block would be
+     * accepted or rejected by its version number. Indeed, if this
+     * check could only be done as part of add, the caller would
+     * either have to add the block to the blockchain first, then
+     * call add, then have to pop the block from the blockchain if
+     * its version did not satisfy the hard fork requirements, or
+     * call add first, then, if the hard fork requirements are met,
+     * add the block to the blockchain, upon which a failure (the
+     * block being invalid, double spending, etc) would cause the
+     * hardfork object to reorganize.
+     */
+    bool check(const cryptonote::block &block) const;
+
+    /**
+     * @brief add a new block
+     *
+     * returns true if no error, false otherwise
+     *
+     * @param block the new block
+     */
+    bool add(const cryptonote::block &block, uint64_t height);
+
+    /**
+     * @brief called when the blockchain is reorganized
+     *
+     * This will rescan the blockchain to determine which hard forks
+     * have been triggered
+     *
+     * returns true if no error, false otherwise
+     *
+     * @param blockchain the blockchain
+     * @param height of the last block kept from the previous blockchain
+     */
+    bool reorganize_from_block_height(uint64_t height);
+    bool reorganize_from_chain_height(uint64_t height);
+
+    /**
+     * @brief returns current state at the given time
+     *
+     * Based on the approximate time of the last known hard fork,
+     * estimate whether we need to update, or if we're way behind
+     *
+     * @param t the time to consider
+     */
+    State get_state(time_t t) const;
+    State get_state() const;
+
+    /**
+     * @brief returns the hard fork version for the given block height
+     *
+     * @param height height of the block to check
+     */
+    uint8_t get(uint64_t height) const;
+
+    /**
+     * @brief returns the height of the first block on the fork with th given version
+     *
+     * @param version version of the fork to query the starting block for
+     */
+    uint64_t get_start_height(uint8_t version) const;
+
+    /**
+     * @brief returns the latest "ideal" version
+     *
+     * This is the latest version that's been scheduled
+     */
+    uint8_t get_ideal_version() const;
+
+    /**
+     * @brief returns the current version
+     *
+     * This is the latest version that's past its trigger date and had enough votes
+     * at one point in the past.
+     */
+    uint8_t get_current_version() const;
+
+    /**
+     * @brief returns information about current voting state
+     *
+     * returns true if the given version is enabled (ie, the current version
+     * is at least the passed version), false otherwise
+     *
+     * @param version the version to check voting for
+     * @param window the number of blocks considered in voting
+     * @param votes number of votes for next version
+     * @param threshold number of votes needed to switch to next version
+     */
+    bool get_voting_info(uint8_t version, uint32_t &window, uint32_t &votes, uint32_t &threshold, uint8_t &voting) const;
+
+    /**
+     * @brief returns the size of the voting window in blocks
+     */
+    uint64_t get_window_size() const { return window_size; }
+
+  private:
+
+    bool do_check(const cryptonote::block &block) const;
+    int get_voted_fork_index(uint64_t height) const;
+    uint8_t get_effective_version(const cryptonote::block &block) const;
+
+  private:
+
+    BlockchainDB &db;
+
+    time_t forked_time;
+    time_t update_time;
+    uint64_t window_size;
+    int threshold_percent;
+
+    uint8_t original_version;
+
+    typedef struct {
+      uint8_t version;
+      uint64_t height;
+      time_t time;
+    } Params;
+    std::vector<Params> heights;
+
+    std::deque<uint8_t> versions; /* rolling window of the last N blocks' versions */
+    unsigned int last_versions[256]; /* count of the block versions in the last N blocks */
+    uint32_t current_fork_index;
+    uint32_t vote_threshold;
+
+    mutable epee::critical_section lock;
+  };
+
+}  // namespace cryptonote
+