daemon: guard against rare 'difficulty drift' bug with checkpoints and recalculation

On startup, it checks against the difficulty checkpoints, and if any mismatch is found, recalculates all the blocks with wrong difficulties. Additionally, once a week it recalculates difficulties of blocks after the last difficulty checkpoint.

1 files changed, 12 insertions, 1 deletions

diff --git a/src/checkpoints/checkpoints.h b/src/checkpoints/checkpoints.h
index a55b94bf0..72e4f875c 100644
--- a/src/checkpoints/checkpoints.h
+++ b/src/checkpoints/checkpoints.h
@@ -33,8 +33,10 @@
 #include "misc_log_ex.h"
 #include "crypto/hash.h"
 #include "cryptonote_config.h"
+#include "cryptonote_basic/difficulty.h"
 
 #define ADD_CHECKPOINT(h, hash)  CHECK_AND_ASSERT(add_checkpoint(h,  hash), false);
+#define ADD_CHECKPOINT2(h, hash, difficulty)  CHECK_AND_ASSERT(add_checkpoint(h,  hash, difficulty), false);
 #define JSON_HASH_FILE_NAME "checkpoints.json"
 
 
@@ -61,12 +63,13 @@ namespace cryptonote
      *
      * @param height the height of the block the checkpoint is for
      * @param hash_str the hash of the block, as a string
+     * @param difficulty_str the cumulative difficulty of the block, as a string (optional)
      *
      * @return false if parsing the hash fails, or if the height is a duplicate
      *         AND the existing checkpoint hash does not match the new one,
      *         otherwise returns true
      */
-    bool add_checkpoint(uint64_t height, const std::string& hash_str);
+    bool add_checkpoint(uint64_t height, const std::string& hash_str, const std::string& difficulty_str = "");
 
     /**
      * @brief checks if there is a checkpoint in the future
@@ -134,6 +137,13 @@ namespace cryptonote
     const std::map<uint64_t, crypto::hash>& get_points() const;
 
     /**
+     * @brief gets the difficulty checkpoints container
+     *
+     * @return a const reference to the difficulty checkpoints container
+     */
+    const std::map<uint64_t, difficulty_type>& get_difficulty_points() const;
+
+    /**
      * @brief checks if our checkpoints container conflicts with another
      *
      * A conflict refers to a case where both checkpoint sets have a checkpoint
@@ -187,6 +197,7 @@ namespace cryptonote
 
   private:
     std::map<uint64_t, crypto::hash> m_points; //!< the checkpoints container
+    std::map<uint64_t, difficulty_type> m_difficulty_points; //!< the difficulty checkpoints container
   };
 
 }