Add intervening v5 fork for increased min block size

Minimum mixin 4 and enforced ringct is moved from v5 to v6.
v5 is now used for an increased minimum block size (from 60000
to 300000) to cater for larger typical/minimum transaction size.

The fee algorithm is also changed to decrease the base per kB
fee, and add a cheap tier for those transactions which we do
not care if they get delayed (or even included in a block).

3 files changed, 28 insertions, 29 deletions

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 0713274a6..5f8db45ad 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -97,8 +97,8 @@ static const struct {
   // version 4 starts from block 1220516, which is on or around the 5th of January, 2017. Fork time finalised on 2016-09-18.
   { 4, 1220516, 0, 1483574400 },
   
-  // version 5 starts from block 1406997, which is on or around the 20th of September, 2017. Fork time finalised on 2016-09-18.
-  { 5, 1406997, 0, 1505865600 },  
+  // version 5 starts from block 1288616, which is on or around the 15th of april, 2017. Fork time finalised on 2016-03-14.
+  { 5, 1288616, 0, 1489520158 },  
 };
 static const uint64_t mainnet_hard_fork_version_1_till = 1009826;
 
@@ -2426,7 +2426,7 @@ bool Blockchain::check_tx_inputs(transaction& tx, tx_verification_context &tvc,
   {
     size_t n_unmixable = 0, n_mixable = 0;
     size_t mixin = std::numeric_limits<size_t>::max();
-    const size_t min_mixin = hf_version >= 5 ? 4 : 2;
+    const size_t min_mixin = hf_version >= HF_VERSION_MIN_MIXIN_4 ? 4 : 2;
     for (const auto& txin : tx.vin)
     {
       // non txin_to_key inputs will be rejected below
@@ -2479,7 +2479,7 @@ bool Blockchain::check_tx_inputs(transaction& tx, tx_verification_context &tvc,
       tvc.m_verifivation_failed = true;
       return false;
     }
-    const size_t min_tx_version = (n_unmixable > 0 ? 1 : (hf_version >= 5) ? 2 : 1);
+    const size_t min_tx_version = (n_unmixable > 0 ? 1 : (hf_version >= HF_VERSION_ENFORCE_RCT) ? 2 : 1);
     if (tx.version < min_tx_version)
     {
       MERROR_VER("transaction version " << (unsigned)tx.version << " is lower than min accepted version " << min_tx_version);
@@ -2809,15 +2809,19 @@ static uint64_t get_fee_quantization_mask()
 }
 
 //------------------------------------------------------------------
-uint64_t Blockchain::get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size)
+uint64_t Blockchain::get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size, uint8_t version)
 {
-  if (median_block_size < CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2)
-    median_block_size = CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2;
+  const uint64_t min_block_size = get_min_block_size(version);
+  const uint64_t fee_per_kb_base = version >= 5 ? DYNAMIC_FEE_PER_KB_BASE_FEE_V5 : DYNAMIC_FEE_PER_KB_BASE_FEE;
 
-  uint64_t unscaled_fee_per_kb = (DYNAMIC_FEE_PER_KB_BASE_FEE * CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2 / median_block_size);
+  if (median_block_size < min_block_size)
+    median_block_size = min_block_size;
+
+  uint64_t unscaled_fee_per_kb = (fee_per_kb_base * min_block_size / 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<uint32_t>::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);
@@ -2848,7 +2852,7 @@ bool Blockchain::check_fee(size_t blob_size, uint64_t fee) const
     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);
+    fee_per_kb = get_dynamic_per_kb_fee(base_reward, median, version);
   }
   MDEBUG("Using " << print_money(fee) << "/kB fee");
 
@@ -2875,14 +2879,15 @@ uint64_t Blockchain::get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks) cons
   if (grace_blocks >= CRYPTONOTE_REWARD_BLOCKS_WINDOW)
     grace_blocks = CRYPTONOTE_REWARD_BLOCKS_WINDOW - 1;
 
+  const uint64_t min_block_size = get_min_block_size(version);
   std::vector<size_t> 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);
+    sz.push_back(min_block_size);
 
   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;
+  if(median <= min_block_size)
+    median = min_block_size;
 
   uint64_t already_generated_coins = m_db->height() ? m_db->get_block_already_generated_coins(m_db->height() - 1) : 0;
   uint64_t base_reward;
@@ -2892,7 +2897,7 @@ uint64_t Blockchain::get_dynamic_per_kb_fee_estimate(uint64_t grace_blocks) cons
     base_reward = BLOCK_REWARD_OVERESTIMATE;
   }
 
-  uint64_t fee = get_dynamic_per_kb_fee(base_reward, median);
+  uint64_t fee = get_dynamic_per_kb_fee(base_reward, median, version);
   MDEBUG("Estimating " << grace_blocks << "-block fee at " << print_money(fee) << "/kB");
   return fee;
 }
@@ -3411,7 +3416,7 @@ leave:
 //------------------------------------------------------------------
 bool Blockchain::update_next_cumulative_size_limit()
 {
-  uint64_t full_reward_zone = get_current_hard_fork_version() < 2 ? CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V1 : CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2;
+  uint64_t full_reward_zone = get_min_block_size(get_current_hard_fork_version());
 
   LOG_PRINT_L3("Blockchain::" << __func__);
   std::vector<size_t> sz;
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index 2c7420e18..7dac608c1 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -520,10 +520,11 @@ namespace cryptonote
      *
      * @param block_reward the current block reward
      * @param median_block_size the median blob's size in the past window
+     * @param version hard fork version for rules and constants to use
      *
      * @return the per kB fee
      */
-    static uint64_t get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size);
+    static uint64_t get_dynamic_per_kb_fee(uint64_t block_reward, size_t median_block_size, uint8_t version);
 
     /**
      * @brief get dynamic per kB fee estimate for the next few blocks
diff --git a/src/cryptonote_core/tx_pool.cpp b/src/cryptonote_core/tx_pool.cpp
index e943c961d..4dd2832ac 100644
--- a/src/cryptonote_core/tx_pool.cpp
+++ b/src/cryptonote_core/tx_pool.cpp
@@ -59,8 +59,6 @@ namespace cryptonote
     //      codebase.  As it stands, it is at best nontrivial to test
     //      whether or not changing these parameters (or adding new)
     //      will work correctly.
-    size_t const TRANSACTION_SIZE_LIMIT_V1 = (((CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V1 * 125) / 100) - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE);
-    size_t const TRANSACTION_SIZE_LIMIT_V2 = (((CRYPTONOTE_BLOCK_GRANTED_FULL_REWARD_ZONE_V2 * 125) / 100) - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE);
     time_t const MIN_RELAY_TIME = (60 * 5); // only start re-relaying transactions after that many seconds
     time_t const MAX_RELAY_TIME = (60 * 60 * 4); // at most that many seconds between resends
     float const ACCEPT_THRESHOLD = 1.0f;
@@ -78,6 +76,11 @@ namespace cryptonote
     {
       return amount * ACCEPT_THRESHOLD;
     }
+
+    uint64_t get_transaction_size_limit(uint8_t version)
+    {
+      return get_min_block_size(version) * 125 / 100 - CRYPTONOTE_COINBASE_BLOB_RESERVED_SIZE;
+    }
   }
   //---------------------------------------------------------------------------------
   //---------------------------------------------------------------------------------
@@ -149,7 +152,7 @@ namespace cryptonote
       return false;
     }
 
-    size_t tx_size_limit = (version < 2 ? TRANSACTION_SIZE_LIMIT_V1 : TRANSACTION_SIZE_LIMIT_V2);
+    size_t tx_size_limit = get_transaction_size_limit(version);
     if (!kept_by_block && blob_size >= tx_size_limit)
     {
       LOG_PRINT_L1("transaction is too big: " << blob_size << " bytes, maximum size: " << tx_size_limit);
@@ -641,15 +644,6 @@ namespace cryptonote
         continue;
       }
 
-#if 1
-      // If we've exceeded the penalty free size,
-      // stop including more tx
-      if (total_size > median_size)
-      {
-        LOG_PRINT_L2("  would exceed median block size");
-        break;
-      }
-#else
       // If we're getting lower coinbase tx,
       // stop including more tx
       uint64_t block_reward;
@@ -666,7 +660,6 @@ namespace cryptonote
         sorted_it++;
         continue;
       }
-#endif
 
       // Skip transactions that are not ready to be
       // included into the blockchain or that are
@@ -705,7 +698,7 @@ namespace cryptonote
   {
     CRITICAL_REGION_LOCAL(m_transactions_lock);
     size_t n_removed = 0;
-    size_t tx_size_limit = (version < 2 ? TRANSACTION_SIZE_LIMIT_V1 : TRANSACTION_SIZE_LIMIT_V2);
+    size_t tx_size_limit = get_transaction_size_limit(version);
     for (auto it = m_transactions.begin(); it != m_transactions.end(); ) {
       if (it->second.blob_size >= tx_size_limit) {
         LOG_PRINT_L1("Transaction " << get_transaction_hash(it->second.tx) << " is too big (" << it->second.blob_size << " bytes), removing it from pool");