4 files changed, 35 insertions, 8 deletions

diff --git a/src/cryptonote_core/blockchain.cpp b/src/cryptonote_core/blockchain.cpp
index 3d586a704..332d4324e 100644
--- a/src/cryptonote_core/blockchain.cpp
+++ b/src/cryptonote_core/blockchain.cpp
@@ -304,7 +304,7 @@ uint64_t Blockchain::get_current_blockchain_height() const
 //------------------------------------------------------------------
 //FIXME: possibly move this into the constructor, to avoid accidentally
 //       dereferencing a null BlockchainDB pointer
-bool Blockchain::init(BlockchainDB* db, const bool testnet, const cryptonote::test_options *test_options)
+bool Blockchain::init(BlockchainDB* db, const bool testnet, bool offline, const cryptonote::test_options *test_options)
 {
   LOG_PRINT_L3("Blockchain::" << __func__);
   CRITICAL_REGION_LOCAL(m_tx_pool);
@@ -326,6 +326,7 @@ bool Blockchain::init(BlockchainDB* db, const bool testnet, const cryptonote::te
   m_db = db;
 
   m_testnet = testnet;
+  m_offline = offline;
   if (m_hardfork == nullptr)
   {
     if (fakechain)
@@ -413,11 +414,11 @@ bool Blockchain::init(BlockchainDB* db, const bool testnet, const cryptonote::te
   return true;
 }
 //------------------------------------------------------------------
-bool Blockchain::init(BlockchainDB* db, HardFork*& hf, const bool testnet)
+bool Blockchain::init(BlockchainDB* db, HardFork*& hf, const bool testnet, bool offline)
 {
   if (hf != nullptr)
     m_hardfork = hf;
-  bool res = init(db, testnet, NULL);
+  bool res = init(db, testnet, offline, NULL);
   if (hf == nullptr)
     hf = m_hardfork;
   return res;
@@ -3624,14 +3625,14 @@ bool Blockchain::update_checkpoints(const std::string& file_path, bool check_dns
 
   // if we're checking both dns and json, load checkpoints from dns.
   // if we're not hard-enforcing dns checkpoints, handle accordingly
-  if (m_enforce_dns_checkpoints && check_dns)
+  if (m_enforce_dns_checkpoints && check_dns && !m_offline)
   {
     if (!m_checkpoints.load_checkpoints_from_dns())
     {
       return false;
     }
   }
-  else if (check_dns)
+  else if (check_dns && !m_offline)
   {
     checkpoints dns_points;
     dns_points.load_checkpoints_from_dns();
diff --git a/src/cryptonote_core/blockchain.h b/src/cryptonote_core/blockchain.h
index e0936da8f..b76d0555f 100644
--- a/src/cryptonote_core/blockchain.h
+++ b/src/cryptonote_core/blockchain.h
@@ -112,11 +112,12 @@ namespace cryptonote
      *
      * @param db a pointer to the backing store to use for the blockchain
      * @param testnet true if on testnet, else false
+     * @param offline true if running offline, else false
      * @param test_options test parameters
      *
      * @return true on success, false if any initialization steps fail
      */
-    bool init(BlockchainDB* db, const bool testnet = false, const cryptonote::test_options *test_options = NULL);
+    bool init(BlockchainDB* db, const bool testnet = false, bool offline = false, const cryptonote::test_options *test_options = NULL);
 
     /**
      * @brief Initialize the Blockchain state
@@ -124,10 +125,11 @@ namespace cryptonote
      * @param db a pointer to the backing store to use for the blockchain
      * @param hf a structure containing hardfork information
      * @param testnet true if on testnet, else false
+     * @param offline true if running offline, else false
      *
      * @return true on success, false if any initialization steps fail
      */
-    bool init(BlockchainDB* db, HardFork*& hf, const bool testnet = false);
+    bool init(BlockchainDB* db, HardFork*& hf, const bool testnet = false, bool offline = false);
 
     /**
      * @brief Uninitializes the blockchain state
@@ -1027,6 +1029,7 @@ namespace cryptonote
     HardFork *m_hardfork;
 
     bool m_testnet;
+    bool m_offline;
 
     std::atomic<bool> m_cancel;
 
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 5c181208f..a6d99424f 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -75,6 +75,10 @@ namespace cryptonote
   , "Run on testnet. The wallet must be launched with --testnet flag."
   , false
   };
+  const command_line::arg_descriptor<bool> arg_offline = {
+    "offline"
+  , "Do not listen for peers, nor connect to any"
+  };
 
   static const command_line::arg_descriptor<bool> arg_test_drop_download = {
     "test-drop-download"
@@ -227,6 +231,7 @@ namespace cryptonote
     command_line::add_arg(desc, arg_check_updates);
     command_line::add_arg(desc, arg_fluffy_blocks);
     command_line::add_arg(desc, arg_test_dbg_lock_sleep);
+    command_line::add_arg(desc, arg_offline);
 
     // we now also need some of net_node's options (p2p bind arg, for separate data dir)
     command_line::add_arg(desc, nodetool::arg_testnet_p2p_bind_port, false);
@@ -264,6 +269,7 @@ namespace cryptonote
     set_enforce_dns_checkpoints(command_line::get_arg(vm, arg_dns_checkpoints));
     test_drop_download_height(command_line::get_arg(vm, arg_test_drop_download_height));
     m_fluffy_blocks_enabled = m_testnet || get_arg(vm, arg_fluffy_blocks);
+    m_offline = get_arg(vm, arg_offline);
 
     if (command_line::get_arg(vm, arg_test_drop_download) == true)
       test_drop_download();
@@ -1322,8 +1328,13 @@ namespace cryptonote
   {
     if(!m_starter_message_showed)
     {
+      std::string main_message;
+      if (m_offline)
+        main_message = "The daemon is running offline and will not attempt to sync to the Monero network.";
+      else
+        main_message = "The daemon will start synchronizing with the network. This may take a long time to complete.";
       MGINFO_YELLOW(ENDL << "**********************************************************************" << ENDL
-        << "The daemon will start synchronizing with the network. This may take a long time to complete." << ENDL
+        << main_message << ENDL
         << ENDL
         << "You can set the level of process detailization* through \"set_log <level|categories>\" command*," << ENDL
         << "where <level> is between 0 (no details) and 4 (very verbose), or custom category based levels (eg, *:WARNING)" << ENDL
@@ -1385,6 +1396,9 @@ namespace cryptonote
     static const char subdir[] = "source"; // because it can never be simple
 #endif
 
+    if (m_offline)
+      return true;
+
     if (check_updates_level == UPDATES_DISABLED)
       return true;
 
diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h
index 905e67f6d..6cb4fc938 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -62,6 +62,7 @@ namespace cryptonote
   extern const command_line::arg_descriptor<std::string> arg_data_dir;
   extern const command_line::arg_descriptor<std::string> arg_testnet_data_dir;
   extern const command_line::arg_descriptor<bool, false> arg_testnet_on;
+  extern const command_line::arg_descriptor<bool> arg_offline;
 
   /************************************************************************/
   /*                                                                      */
@@ -773,6 +774,13 @@ namespace cryptonote
       */
      uint64_t get_free_space() const;
 
+     /**
+      * @brief get whether the core is running offline
+      *
+      * @return whether the core is running offline
+      */
+     bool offline() const { return m_offline; }
+
    private:
 
      /**
@@ -1000,6 +1008,7 @@ namespace cryptonote
      boost::mutex m_update_mutex;
 
      bool m_fluffy_blocks_enabled;
+     bool m_offline;
    };
 }