Merge pull request #1263

d61bd81 add lightweight block propagation ("fluffy blocks") (Dion Ahmetaj)

11 files changed, 492 insertions, 11 deletions

diff --git a/src/cryptonote_config.h b/src/cryptonote_config.h
index 175a5d26e..95cbf74f0 100644
--- a/src/cryptonote_config.h
+++ b/src/cryptonote_config.h
@@ -113,6 +113,9 @@
 #define P2P_IP_FAILS_BEFORE_BLOCK                       10
 #define P2P_IDLE_CONNECTION_KILL_INTERVAL               (5*60) //5 minutes
 
+#define P2P_SUPPORT_FLAG_FLUFFY_BLOCKS                  0x01
+#define P2P_SUPPORT_FLAGS                               P2P_SUPPORT_FLAG_FLUFFY_BLOCKS
+
 #define ALLOW_DEBUG_COMMANDS
 
 #define CRYPTONOTE_NAME                         "bitmonero"
diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 95c49f627..9deb8863d 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -915,6 +915,11 @@ namespace cryptonote
     m_mempool.get_transactions(txs);
     return true;
   }
+  //-----------------------------------------------------------------------------------------------  
+  bool core::get_pool_transaction(const crypto::hash &id, transaction& tx) const
+  {
+    return m_mempool.get_transaction(id, tx);
+  }  
   //-----------------------------------------------------------------------------------------------
   bool core::get_pool_transactions_and_spent_keys_info(std::vector<tx_info>& tx_infos, std::vector<spent_key_image_info>& key_image_infos) const
   {
diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h
index a5a97a5ad..5ddab4ed4 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -379,6 +379,13 @@ namespace cryptonote
       * @note see tx_memory_pool::get_transactions
       */
      bool get_pool_transactions(std::list<transaction>& txs) const;
+     
+     /**
+      * @copydoc tx_memory_pool::get_transaction
+      *
+      * @note see tx_memory_pool::get_transaction
+      */
+     bool get_pool_transaction(const crypto::hash& id, transaction& tx) const;     
 
      /**
       * @copydoc tx_memory_pool::get_pool_transactions_and_spent_keys_info
@@ -611,6 +618,13 @@ namespace cryptonote
       * @return the number of blocks to sync in one go
       */
      std::pair<uint64_t, uint64_t> get_coinbase_tx_sum(const uint64_t start_offset, const size_t count);
+     
+     /**
+      * @brief get whether we're on testnet or not
+      *
+      * @return are we on testnet?
+      */     
+     bool get_testnet() const { return m_testnet; };
 
    private:
 
diff --git a/src/cryptonote_protocol/cryptonote_protocol_defs.h b/src/cryptonote_protocol/cryptonote_protocol_defs.h
index edcf2af8e..7adc69080 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_defs.h
+++ b/src/cryptonote_protocol/cryptonote_protocol_defs.h
@@ -69,6 +69,8 @@ namespace cryptonote
 	
 	uint64_t avg_upload;
 	uint64_t current_upload;
+  
+	uint32_t support_flags;
 
     BEGIN_KV_SERIALIZE_MAP()
       KV_SERIALIZE(incoming)
@@ -87,6 +89,7 @@ namespace cryptonote
       KV_SERIALIZE(current_download)
       KV_SERIALIZE(avg_upload)
       KV_SERIALIZE(current_upload)
+      KV_SERIALIZE(support_flags)
     END_KV_SERIALIZE_MAP()
   };
 
@@ -223,5 +226,49 @@ namespace cryptonote
       END_KV_SERIALIZE_MAP()
     };
   };
+  
+  /************************************************************************/
+  /*                                                                      */
+  /************************************************************************/
+  struct NOTIFY_NEW_FLUFFY_BLOCK
+  {
+    const static int ID = BC_COMMANDS_POOL_BASE + 8;
+
+    struct request
+    {
+      block_complete_entry b;
+      uint64_t current_blockchain_height;
+      uint32_t hop;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(b)
+        KV_SERIALIZE(current_blockchain_height)
+        KV_SERIALIZE(hop)
+      END_KV_SERIALIZE_MAP()
+    };
+  };  
+
+  /************************************************************************/
+  /*                                                                      */
+  /************************************************************************/
+  struct NOTIFY_REQUEST_FLUFFY_MISSING_TX
+  {
+    const static int ID = BC_COMMANDS_POOL_BASE + 9;
 
+    struct request
+    {
+      block_complete_entry b;
+      uint64_t current_blockchain_height;      
+      std::vector<size_t> missing_tx_indices;
+      uint32_t hop;
+      
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(b)
+        KV_SERIALIZE_CONTAINER_POD_AS_BLOB(missing_tx_indices)        
+        KV_SERIALIZE(hop)   
+        KV_SERIALIZE(current_blockchain_height)     
+      END_KV_SERIALIZE_MAP()
+    };
+  }; 
+    
 }
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.h b/src/cryptonote_protocol/cryptonote_protocol_handler.h
index 1c92958c9..ab5d8230d 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.h
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.h
@@ -91,6 +91,8 @@ namespace cryptonote
       HANDLE_NOTIFY_T2(NOTIFY_RESPONSE_GET_OBJECTS, &cryptonote_protocol_handler::handle_response_get_objects)
       HANDLE_NOTIFY_T2(NOTIFY_REQUEST_CHAIN, &cryptonote_protocol_handler::handle_request_chain)
       HANDLE_NOTIFY_T2(NOTIFY_RESPONSE_CHAIN_ENTRY, &cryptonote_protocol_handler::handle_response_chain_entry)
+      HANDLE_NOTIFY_T2(NOTIFY_NEW_FLUFFY_BLOCK, &cryptonote_protocol_handler::handle_notify_new_fluffy_block)			
+      HANDLE_NOTIFY_T2(NOTIFY_REQUEST_FLUFFY_MISSING_TX, &cryptonote_protocol_handler::handle_request_fluffy_missing_tx)						
     END_INVOKE_MAP2()
 
     bool on_idle();
@@ -115,8 +117,9 @@ namespace cryptonote
     int handle_response_get_objects(int command, NOTIFY_RESPONSE_GET_OBJECTS::request& arg, cryptonote_connection_context& context);
     int handle_request_chain(int command, NOTIFY_REQUEST_CHAIN::request& arg, cryptonote_connection_context& context);
     int handle_response_chain_entry(int command, NOTIFY_RESPONSE_CHAIN_ENTRY::request& arg, cryptonote_connection_context& context);
-
-
+    int handle_notify_new_fluffy_block(int command, NOTIFY_NEW_FLUFFY_BLOCK::request& arg, cryptonote_connection_context& context);
+    int handle_request_fluffy_missing_tx(int command, NOTIFY_REQUEST_FLUFFY_MISSING_TX::request& arg, cryptonote_connection_context& context);
+		
     //----------------- i_bc_protocol_layout ---------------------------------------
     virtual bool relay_block(NOTIFY_NEW_BLOCK::request& arg, cryptonote_connection_context& exclude_context);
     virtual bool relay_transactions(NOTIFY_NEW_TRANSACTIONS::request& arg, cryptonote_connection_context& exclude_context);
diff --git a/src/cryptonote_protocol/cryptonote_protocol_handler.inl b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
index 10756a8ad..65377f990 100644
--- a/src/cryptonote_protocol/cryptonote_protocol_handler.inl
+++ b/src/cryptonote_protocol/cryptonote_protocol_handler.inl
@@ -37,6 +37,7 @@
 
 #include <boost/interprocess/detail/atomic.hpp>
 #include <list>
+#include <unordered_map>
 
 #include "cryptonote_core/cryptonote_format_utils.h"
 #include "profile_tools.h"
@@ -124,6 +125,7 @@ namespace cryptonote
 
     ss << std::setw(30) << std::left << "Remote Host"
       << std::setw(20) << "Peer id"
+      << std::setw(20) << "Support Flags"      
       << std::setw(30) << "Recv/Sent (inactive,sec)"
       << std::setw(25) << "State"
       << std::setw(20) << "Livetime(sec)"
@@ -134,7 +136,7 @@ namespace cryptonote
       << ENDL;
 
     uint32_t ip;
-    m_p2p->for_each_connection([&](const connection_context& cntxt, nodetool::peerid_type peer_id)
+    m_p2p->for_each_connection([&](const connection_context& cntxt, nodetool::peerid_type peer_id, uint32_t support_flags)
     {
       bool local_ip = false;
       ip = ntohl(cntxt.m_remote_ip);
@@ -145,6 +147,7 @@ namespace cryptonote
       ss << std::setw(30) << std::left << std::string(cntxt.m_is_income ? " [INC]":"[OUT]") +
         epee::string_tools::get_ip_string_from_int32(cntxt.m_remote_ip) + ":" + std::to_string(cntxt.m_remote_port)
         << std::setw(20) << std::hex << peer_id
+        << std::setw(20) << std::hex << support_flags
         << std::setw(30) << std::to_string(cntxt.m_recv_cnt)+ "(" + std::to_string(time(NULL) - cntxt.m_last_recv) + ")" + "/" + std::to_string(cntxt.m_send_cnt) + "(" + std::to_string(time(NULL) - cntxt.m_last_send) + ")"
         << std::setw(25) << get_protocol_state_string(cntxt.m_state)
         << std::setw(20) << std::to_string(time(NULL) - cntxt.m_started)
@@ -184,7 +187,7 @@ namespace cryptonote
   {
     std::list<connection_info> connections;
 
-    m_p2p->for_each_connection([&](const connection_context& cntxt, nodetool::peerid_type peer_id)
+    m_p2p->for_each_connection([&](const connection_context& cntxt, nodetool::peerid_type peer_id, uint32_t support_flags)
     {
       connection_info cnx;
       auto timestamp = time(NULL);
@@ -197,6 +200,8 @@ namespace cryptonote
       std::stringstream peer_id_str;
       peer_id_str << std::hex << peer_id;
       peer_id_str >> cnx.peer_id;
+      
+      cnx.support_flags = support_flags;
 
       cnx.recv_count = cntxt.m_recv_cnt;
       cnx.recv_idle_time = timestamp - cntxt.m_last_recv;
@@ -361,6 +366,312 @@ namespace cryptonote
   }
   //------------------------------------------------------------------------------------------------------------------------
   template<class t_core>
+  int t_cryptonote_protocol_handler<t_core>::handle_notify_new_fluffy_block(int command, NOTIFY_NEW_FLUFFY_BLOCK::request& arg, cryptonote_connection_context& context)
+  {
+    LOG_PRINT_CCONTEXT_L2("NOTIFY_NEW_FLUFFY_BLOCK (hop " << arg.hop << ")");
+    if(context.m_state != cryptonote_connection_context::state_normal)
+      return 1;
+    
+    m_core.pause_mine();
+      
+    block new_block;
+    transaction miner_tx;
+    if(parse_and_validate_block_from_blob(arg.b.block, new_block))
+    {
+      // This is a seccond notification, we must have asked for some missing tx
+      if(!context.m_requested_objects.empty())
+      {
+        // What we asked for != to what we received ..
+        if(context.m_requested_objects.size() != arg.b.txs.size())
+        {
+          LOG_ERROR_CCONTEXT
+          (
+            "NOTIFY_NEW_FLUFFY_BLOCK -> request/response mismatch, " 
+            << "block = " << epee::string_tools::pod_to_hex(get_blob_hash(arg.b.block))
+            << ", requested = " << context.m_requested_objects.size() 
+            << ", received = " << new_block.tx_hashes.size()
+            << ", dropping connection"
+          );
+          
+          m_p2p->drop_connection(context);
+          m_core.resume_mine();
+          return 1;
+        }
+      }      
+      
+      std::list<blobdata> have_tx;
+      
+      // Instead of requesting missing transactions by hash like BTC, 
+      // we do it by index (thanks to a suggestion from moneromooo) because
+      // we're way cooler .. and also because they're smaller than hashes.
+      // 
+      // Also, remember to pepper some whitespace changes around to bother
+      // moneromooo ... only because I <3 him. 
+      std::vector<size_t> need_tx_indices;
+        
+      transaction tx;
+      crypto::hash tx_hash;
+
+      BOOST_FOREACH(auto& tx_blob, arg.b.txs)
+      {
+        if(parse_and_validate_tx_from_blob(tx_blob, tx))
+        {
+          try
+          {
+            if(!get_transaction_hash(tx, tx_hash))
+            {
+              LOG_PRINT_CCONTEXT_L1
+              (
+                  "NOTIFY_NEW_FLUFFY_BLOCK: get_transaction_hash failed"
+                  << ", dropping connection"
+              );
+              
+              m_p2p->drop_connection(context);
+              m_core.resume_mine();
+              return 1;
+            }
+          }
+          catch(...)
+          {
+            LOG_PRINT_CCONTEXT_L1
+            (
+                "NOTIFY_NEW_FLUFFY_BLOCK: get_transaction_hash failed"
+                << ", exception thrown"
+                << ", dropping connection"
+            );
+                        
+            m_p2p->drop_connection(context);
+            m_core.resume_mine();
+            return 1;
+          }
+          
+          // hijacking m_requested objects in connection context to patch up
+          // a possible DOS vector pointed out by @monero-moo where peers keep
+          // sending (0...n-1) transactions.
+          // If requested objects is not empty, then we must have asked for 
+          // some missing transacionts, make sure that they're all there.
+          //
+          // Can I safely re-use this field? I think so, but someone check me!
+          if(!context.m_requested_objects.empty()) 
+          {
+            auto req_tx_it = context.m_requested_objects.find(tx_hash);
+            if(req_tx_it == context.m_requested_objects.end())
+            {
+              LOG_ERROR_CCONTEXT
+              (
+                "Peer sent wrong transaction (NOTIFY_NEW_FLUFFY_BLOCK): "
+                << "transaction with id = " << tx_hash << " wasn't requested, "
+                << "dropping connection"
+              );
+              
+              m_p2p->drop_connection(context);
+              m_core.resume_mine();
+              return 1;
+            }
+            
+            context.m_requested_objects.erase(req_tx_it);
+          }          
+          
+          // we might already have the tx that the peer
+          // sent in our pool, so don't verify again..
+          if(!m_core.get_pool_transaction(tx_hash, tx))
+          {
+            cryptonote::tx_verification_context tvc = AUTO_VAL_INIT(tvc);                        
+            if(!m_core.handle_incoming_tx(tx_blob, tvc, true, true) || tvc.m_verifivation_failed)
+            {
+              LOG_PRINT_CCONTEXT_L1("Block verification failed: transaction verification failed, dropping connection");
+              m_p2p->drop_connection(context);
+              m_core.resume_mine();
+              return 1;
+            }
+            
+            //
+            // future todo: 
+            // tx should only not be added to pool if verification failed, but
+            // maybe in the future could not be added for other reasons 
+            // according to monero-moo so keep track of these separately ..
+            //
+          }
+        }
+        else
+        {
+          LOG_ERROR_CCONTEXT
+          (
+            "sent wrong tx: failed to parse and validate transaction: \r\n"
+            << epee::string_tools::buff_to_hex_nodelimer(tx_blob) 
+            << "\r\n dropping connection"
+          );
+            
+          m_p2p->drop_connection(context);
+          m_core.resume_mine();
+          return 1;
+        }
+      }
+      
+      // The initial size equality check could have been fooled if the sender
+      // gave us the number of transactions we asked for, but not the right 
+      // ones. This check make sure the transactions we asked for were the
+      // ones we received.
+      if(context.m_requested_objects.size())
+      {
+        LOG_PRINT_CCONTEXT_RED
+        (
+          "NOTIFY_NEW_FLUFFY_BLOCK: peer sent the number of transaction requested"
+          << ", but not the actual transactions requested"
+          << ", context.m_requested_objects.size() = " << context.m_requested_objects.size() 
+          << ", dropping connection", LOG_LEVEL_0
+        );
+        
+        m_p2p->drop_connection(context);
+        m_core.resume_mine();
+        return 1;
+      }      
+      
+      size_t tx_idx = 0;
+      BOOST_FOREACH(auto& tx_hash, new_block.tx_hashes)
+      {
+        if(m_core.get_pool_transaction(tx_hash, tx))
+        {
+          have_tx.push_back(tx_to_blob(tx));
+        }
+        else
+        {
+          need_tx_indices.push_back(tx_idx); 
+        }
+        
+        ++tx_idx;
+      }
+        
+      if(!need_tx_indices.empty()) // drats, we don't have everything..
+      {
+        // request non-mempool txs
+        NOTIFY_REQUEST_FLUFFY_MISSING_TX::request missing_tx_req;
+        missing_tx_req.b = arg.b;
+        missing_tx_req.hop = arg.hop;
+        missing_tx_req.current_blockchain_height = arg.current_blockchain_height;
+        missing_tx_req.missing_tx_indices = std::move(need_tx_indices);
+        
+        m_core.resume_mine();
+        post_notify<NOTIFY_REQUEST_FLUFFY_MISSING_TX>(missing_tx_req, context);
+      }
+      else // whoo-hoo we've got em all ..
+      {
+        block_complete_entry b;
+        b.block = arg.b.block;
+        b.txs = have_tx;
+
+        std::list<block_complete_entry> blocks;
+        blocks.push_back(b);
+        m_core.prepare_handle_incoming_blocks(blocks);
+          
+        block_verification_context bvc = boost::value_initialized<block_verification_context>();
+        m_core.handle_incoming_block(arg.b.block, bvc); // got block from handle_notify_new_block
+        m_core.cleanup_handle_incoming_blocks(true);
+        m_core.resume_mine();
+        
+        if( bvc.m_verifivation_failed )
+        {
+          LOG_PRINT_CCONTEXT_L0("Block verification failed, dropping connection");
+          m_p2p->drop_connection(context);
+          return 1;
+        }
+        if( bvc.m_added_to_main_chain )
+        {
+          ++arg.hop;
+          //TODO: Add here announce protocol usage
+          NOTIFY_NEW_BLOCK::request reg_arg = AUTO_VAL_INIT(reg_arg);
+          reg_arg.hop = arg.hop;
+          reg_arg.current_blockchain_height = arg.current_blockchain_height;
+          reg_arg.b.block = b.block;
+          relay_block(reg_arg, context);
+        }
+        else if( bvc.m_marked_as_orphaned )
+        {
+          context.m_state = cryptonote_connection_context::state_synchronizing;
+          NOTIFY_REQUEST_CHAIN::request r = boost::value_initialized<NOTIFY_REQUEST_CHAIN::request>();
+          m_core.get_short_chain_history(r.block_ids);
+          LOG_PRINT_CCONTEXT_L2("-->>NOTIFY_REQUEST_CHAIN: m_block_ids.size()=" << r.block_ids.size() );
+          post_notify<NOTIFY_REQUEST_CHAIN>(r, context);
+        }            
+      }
+    } 
+    else
+    {
+      LOG_ERROR_CCONTEXT
+      (
+        "sent wrong block: failed to parse and validate block: \r\n"
+        << epee::string_tools::buff_to_hex_nodelimer(arg.b.block) 
+        << "\r\n dropping connection"
+      );
+        
+      m_core.resume_mine();
+      m_p2p->drop_connection(context);
+        
+      return 1;     
+    }
+        
+    return 1;
+  }  
+  //------------------------------------------------------------------------------------------------------------------------  
+  template<class t_core>
+  int t_cryptonote_protocol_handler<t_core>::handle_request_fluffy_missing_tx(int command, NOTIFY_REQUEST_FLUFFY_MISSING_TX::request& arg, cryptonote_connection_context& context)
+  {
+    LOG_PRINT_CCONTEXT_L2("NOTIFY_REQUEST_FLUFFY_MISSING_TX");
+    
+    std::list<block> local_blocks;
+    std::list<transaction> local_txs;
+    if(!m_core.get_blocks(arg.current_blockchain_height - 1, 1, local_blocks, local_txs))
+    {
+
+      LOG_ERROR_CCONTEXT
+      (
+        "Failed to handle request NOTIFY_REQUEST_FLUFFY_MISSING_TX"
+        << ", get_blocks( start_offset = " << (arg.current_blockchain_height - 1) << " ) failed"
+        << ", dropping connection"
+      );
+      
+      m_p2p->drop_connection(context);
+      return 1;            
+    }
+
+    NOTIFY_NEW_FLUFFY_BLOCK::request fluffy_response;
+    fluffy_response.b = arg.b;
+    fluffy_response.current_blockchain_height = m_core.get_current_blockchain_height();
+    fluffy_response.hop = arg.hop;    
+    size_t local_txs_count = local_txs.size();
+    BOOST_FOREACH(auto& tx_idx, arg.missing_tx_indices)
+    {
+      if(tx_idx < local_txs_count)
+      {
+        fluffy_response.b.txs.push_back(t_serializable_object_to_blob( *(std::next(local_txs.begin(), tx_idx)) ));
+      }
+      else
+      {
+        LOG_ERROR_CCONTEXT
+        (
+          "Failed to handle request NOTIFY_REQUEST_FLUFFY_MISSING_TX"
+          << ", request is asking for a tx whose index is out of bounds "
+          << ", tx index = " << tx_idx << ", block_height = " << arg.current_blockchain_height
+          << ", dropping connection"
+        );
+        
+        m_p2p->drop_connection(context);
+        return 1;
+      }
+    }    
+            
+    LOG_PRINT_CCONTEXT_L2
+    (
+        "-->>NOTIFY_RESPONSE_FLUFFY_MISSING_TX: " 
+        << ", txs.size()=" << fluffy_response.b.txs.size()
+        << ", rsp.current_blockchain_height=" << fluffy_response.current_blockchain_height
+    );
+           
+    post_notify<NOTIFY_NEW_FLUFFY_BLOCK>(fluffy_response, context);    
+    return 1;        
+  }
+  //------------------------------------------------------------------------------------------------------------------------
+  template<class t_core>
   int t_cryptonote_protocol_handler<t_core>::handle_notify_new_transactions(int command, NOTIFY_NEW_TRANSACTIONS::request& arg, cryptonote_connection_context& context)
   {
     LOG_PRINT_CCONTEXT_L2("NOTIFY_NEW_TRANSACTIONS");
@@ -775,7 +1086,28 @@ namespace cryptonote
   template<class t_core>
   bool t_cryptonote_protocol_handler<t_core>::relay_block(NOTIFY_NEW_BLOCK::request& arg, cryptonote_connection_context& exclude_context)
   {
-    return relay_post_notify<NOTIFY_NEW_BLOCK>(arg, exclude_context);
+    NOTIFY_NEW_FLUFFY_BLOCK::request fluffy_arg = AUTO_VAL_INIT(fluffy_arg);
+    fluffy_arg.hop = arg.hop;
+    fluffy_arg.current_blockchain_height = arg.current_blockchain_height;    
+    std::list<blobdata> fluffy_txs;
+    fluffy_arg.b = arg.b;
+    fluffy_arg.b.txs = fluffy_txs;
+        
+    m_p2p->for_each_connection([this, &arg, &fluffy_arg](connection_context& cntxt, nodetool::peerid_type peer_id, uint32_t support_flags)
+    {
+      if(m_core.get_testnet() && support_flags & P2P_SUPPORT_FLAG_FLUFFY_BLOCKS)
+      {
+        LOG_PRINT_YELLOW("PEER SUPPORTS FLUFFY BLOCKS - RELAYING THIN/COMPACT WHATEVER BLOCK", LOG_LEVEL_1);
+        return post_notify<NOTIFY_NEW_FLUFFY_BLOCK>(fluffy_arg, cntxt);
+      }
+      else
+      {
+        LOG_PRINT_YELLOW("PEER DOESN'T SUPPORT FLUFFY BLOCKS - RELAYING FULL BLOCK", LOG_LEVEL_1);
+        return post_notify<NOTIFY_NEW_BLOCK>(arg, cntxt);
+      }
+    });
+    
+    return 1;
   }
   //------------------------------------------------------------------------------------------------------------------------
   template<class t_core>
diff --git a/src/daemon/rpc_command_executor.cpp b/src/daemon/rpc_command_executor.cpp
index 7d50ae76b..65b42cc47 100644
--- a/src/daemon/rpc_command_executor.cpp
+++ b/src/daemon/rpc_command_executor.cpp
@@ -404,6 +404,7 @@ bool t_rpc_command_executor::print_connections() {
 
   tools::msg_writer() << std::setw(30) << std::left << "Remote Host"
       << std::setw(20) << "Peer id"
+      << std::setw(20) << "Support Flags"      
       << std::setw(30) << "Recv/Sent (inactive,sec)"
       << std::setw(25) << "State"
       << std::setw(20) << "Livetime(sec)"
@@ -422,6 +423,7 @@ bool t_rpc_command_executor::print_connections() {
      //<< std::setw(30) << std::left << in_out
      << std::setw(30) << std::left << address
      << std::setw(20) << info.peer_id
+     << std::setw(20) << info.support_flags
      << std::setw(30) << std::to_string(info.recv_count) + "("  + std::to_string(info.recv_idle_time) + ")/" + std::to_string(info.send_count) + "(" + std::to_string(info.send_idle_time) + ")"
      << std::setw(25) << info.state
      << std::setw(20) << info.live_time
diff --git a/src/p2p/net_node.h b/src/p2p/net_node.h
index 5943c248f..619bad40f 100644
--- a/src/p2p/net_node.h
+++ b/src/p2p/net_node.h
@@ -63,6 +63,7 @@ namespace nodetool
   struct p2p_connection_context_t: base_type //t_payload_net_handler::connection_context //public net_utils::connection_context_base
   {
     peerid_type peer_id;
+    uint32_t support_flags;
   };
 
   template<class t_payload_net_handler>
@@ -146,6 +147,7 @@ namespace nodetool
       HANDLE_INVOKE_T2(COMMAND_REQUEST_NETWORK_STATE, &node_server::handle_get_network_state)
       HANDLE_INVOKE_T2(COMMAND_REQUEST_PEER_ID, &node_server::handle_get_peer_id)
 #endif
+      HANDLE_INVOKE_T2(COMMAND_REQUEST_SUPPORT_FLAGS, &node_server::handle_get_support_flags)
       CHAIN_INVOKE_MAP_TO_OBJ_FORCE_CONTEXT(m_payload_handler, typename t_payload_net_handler::connection_context&)
     END_INVOKE_MAP2()
 
@@ -158,6 +160,7 @@ namespace nodetool
     int handle_get_network_state(int command, COMMAND_REQUEST_NETWORK_STATE::request& arg, COMMAND_REQUEST_NETWORK_STATE::response& rsp, p2p_connection_context& context);
     int handle_get_peer_id(int command, COMMAND_REQUEST_PEER_ID::request& arg, COMMAND_REQUEST_PEER_ID::response& rsp, p2p_connection_context& context);
 #endif
+    int handle_get_support_flags(int command, COMMAND_REQUEST_SUPPORT_FLAGS::request& arg, COMMAND_REQUEST_SUPPORT_FLAGS::response& rsp, p2p_connection_context& context);
     bool init_config();
     bool make_default_config();
     bool store_config();
@@ -174,7 +177,7 @@ namespace nodetool
     virtual bool invoke_notify_to_peer(int command, const std::string& req_buff, const epee::net_utils::connection_context_base& context);
     virtual bool drop_connection(const epee::net_utils::connection_context_base& context);
     virtual void request_callback(const epee::net_utils::connection_context_base& context);
-    virtual void for_each_connection(std::function<bool(typename t_payload_net_handler::connection_context&, peerid_type)> f);
+    virtual void for_each_connection(std::function<bool(typename t_payload_net_handler::connection_context&, peerid_type, uint32_t)> f);
     virtual bool add_ip_fail(uint32_t address);
     //----------------- i_connection_filter  --------------------------------------------------------
     virtual bool is_remote_ip_allowed(uint32_t adress);
@@ -204,6 +207,7 @@ namespace nodetool
     bool is_addr_connected(const net_address& peer);
     template<class t_callback>
     bool try_ping(basic_node_data& node_data, p2p_connection_context& context, t_callback cb);
+    bool try_get_support_flags(const p2p_connection_context& context, std::function<void(p2p_connection_context&, const uint32_t&)> f);
     bool make_expected_connections_count(bool white_list, size_t expected_connections);
     void cache_connect_fail_info(const net_address& addr);
     bool is_addr_recently_failed(const net_address& addr);
@@ -240,10 +244,12 @@ namespace nodetool
     {
       network_config m_net_config;
       uint64_t m_peer_id;
+      uint32_t m_support_flags;
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(m_net_config)
         KV_SERIALIZE(m_peer_id)
+        KV_SERIALIZE(m_support_flags)
       END_KV_SERIALIZE_MAP()
     };
 
diff --git a/src/p2p/net_node.inl b/src/p2p/net_node.inl
index 04d73ba95..d8dadae1f 100644
--- a/src/p2p/net_node.inl
+++ b/src/p2p/net_node.inl
@@ -158,6 +158,7 @@ namespace nodetool
     m_config.m_net_config.connection_timeout = P2P_DEFAULT_CONNECTION_TIMEOUT;
     m_config.m_net_config.ping_connection_timeout = P2P_DEFAULT_PING_CONNECTION_TIMEOUT;
     m_config.m_net_config.send_peerlist_sz = P2P_DEFAULT_PEERS_IN_HANDSHAKE;
+    m_config.m_support_flags = P2P_SUPPORT_FLAGS;
 
     m_first_connection_maker_call = true;
     CATCH_ENTRY_L0("node_server::init_config", false);
@@ -165,10 +166,10 @@ namespace nodetool
   }
   //-----------------------------------------------------------------------------------
   template<class t_payload_net_handler>
-  void node_server<t_payload_net_handler>::for_each_connection(std::function<bool(typename t_payload_net_handler::connection_context&, peerid_type)> f)
+  void node_server<t_payload_net_handler>::for_each_connection(std::function<bool(typename t_payload_net_handler::connection_context&, peerid_type, uint32_t)> f)
   {
     m_net_server.get_config_object().foreach_connection([&](p2p_connection_context& cntx){
-      return f(cntx, cntx.peer_id);
+      return f(cntx, cntx.peer_id, cntx.support_flags);
     });
   }
   //-----------------------------------------------------------------------------------
@@ -730,6 +731,13 @@ namespace nodetool
       LOG_PRINT_CC_L1(context_, "COMMAND_HANDSHAKE Failed");
       m_net_server.get_config_object().close(context_.m_connection_id);
     }
+    else
+    {
+      try_get_support_flags(context_, [](p2p_connection_context& flags_context, const uint32_t& support_flags) 
+      {
+        flags_context.support_flags = support_flags;
+      });
+    }
 
     return hsh_result;
   }
@@ -1221,6 +1229,13 @@ namespace nodetool
 #endif
   //-----------------------------------------------------------------------------------
   template<class t_payload_net_handler>
+  int node_server<t_payload_net_handler>::handle_get_support_flags(int command, COMMAND_REQUEST_SUPPORT_FLAGS::request& arg, COMMAND_REQUEST_SUPPORT_FLAGS::response& rsp, p2p_connection_context& context)
+  {
+    rsp.support_flags = m_config.m_support_flags;
+    return 1;
+  }
+  //-----------------------------------------------------------------------------------
+  template<class t_payload_net_handler>
   void node_server<t_payload_net_handler>::request_callback(const epee::net_utils::connection_context_base& context)
   {
     m_net_server.get_config_object().request_callback(context.m_connection_id);
@@ -1338,6 +1353,32 @@ namespace nodetool
   }
   //-----------------------------------------------------------------------------------
   template<class t_payload_net_handler>
+  bool node_server<t_payload_net_handler>::try_get_support_flags(const p2p_connection_context& context, std::function<void(p2p_connection_context&, const uint32_t&)> f)
+  {
+    COMMAND_REQUEST_SUPPORT_FLAGS::request support_flags_request;
+    bool r = epee::net_utils::async_invoke_remote_command2<typename COMMAND_REQUEST_SUPPORT_FLAGS::response>
+    (
+      context.m_connection_id, 
+      COMMAND_REQUEST_SUPPORT_FLAGS::ID, 
+      support_flags_request, 
+      m_net_server.get_config_object(),
+      [=](int code, const typename COMMAND_REQUEST_SUPPORT_FLAGS::response& rsp, p2p_connection_context& context_)
+      {  
+        if(code < 0)
+        {
+          LOG_PRINT_CC_RED(context_, "COMMAND_REQUEST_SUPPORT_FLAGS invoke failed. (" << code <<  ", " << epee::levin::get_err_descr(code) << ")", LOG_LEVEL_1);
+          return;
+        }
+        
+        f(context_, rsp.support_flags);
+      },
+      P2P_DEFAULT_HANDSHAKE_INVOKE_TIMEOUT
+    );
+
+    return r;
+  }  
+  //-----------------------------------------------------------------------------------
+  template<class t_payload_net_handler>
   int node_server<t_payload_net_handler>::handle_timed_sync(int command, typename COMMAND_TIMED_SYNC::request& arg, typename COMMAND_TIMED_SYNC::response& rsp, p2p_connection_context& context)
   {
     if(!m_payload_handler.process_payload_sync_data(arg.payload_data, context, false))
@@ -1394,7 +1435,7 @@ namespace nodetool
     if(arg.node_data.peer_id != m_config.m_peer_id && arg.node_data.my_port)
     {
       peerid_type peer_id_l = arg.node_data.peer_id;
-      uint32_t port_l = arg.node_data.my_port;
+      uint32_t port_l = arg.node_data.my_port;      
       //try ping to be sure that we can add this peer to peer_list
       try_ping(arg.node_data, context, [peer_id_l, port_l, context, this]()
       {
@@ -1410,6 +1451,11 @@ namespace nodetool
         LOG_PRINT_CCONTEXT_L2("PING SUCCESS " << epee::string_tools::get_ip_string_from_int32(context.m_remote_ip) << ":" << port_l);
       });
     }
+    
+    try_get_support_flags(context, [](p2p_connection_context& flags_context, const uint32_t& support_flags) 
+    {
+      flags_context.support_flags = support_flags;
+    });
 
     //fill response
     m_peerlist.get_peerlist_head(rsp.local_peerlist);
diff --git a/src/p2p/net_node_common.h b/src/p2p/net_node_common.h
index 5e7645365..846c07779 100644
--- a/src/p2p/net_node_common.h
+++ b/src/p2p/net_node_common.h
@@ -49,7 +49,7 @@ namespace nodetool
     virtual bool drop_connection(const epee::net_utils::connection_context_base& context)=0;
     virtual void request_callback(const epee::net_utils::connection_context_base& context)=0;
     virtual uint64_t get_connections_count()=0;
-    virtual void for_each_connection(std::function<bool(t_connection_context&, peerid_type)> f)=0;
+    virtual void for_each_connection(std::function<bool(t_connection_context&, peerid_type, uint32_t)> f)=0;
     virtual bool block_ip(uint32_t adress, time_t seconds = 0)=0;
     virtual bool unblock_ip(uint32_t adress)=0;
     virtual std::map<uint32_t, time_t> get_blocked_ips()=0;
@@ -79,7 +79,7 @@ namespace nodetool
     {
 
     }
-    virtual void for_each_connection(std::function<bool(t_connection_context&,peerid_type)> f)
+    virtual void for_each_connection(std::function<bool(t_connection_context&,peerid_type,uint32_t)> f)
     {
 
     }
diff --git a/src/p2p/p2p_protocol_defs.h b/src/p2p/p2p_protocol_defs.h
index bad4c89e3..ce1ee1449 100644
--- a/src/p2p/p2p_protocol_defs.h
+++ b/src/p2p/p2p_protocol_defs.h
@@ -332,6 +332,29 @@ namespace nodetool
     };
   };
 
+  /************************************************************************/
+  /*                                                                      */
+  /************************************************************************/
+  struct COMMAND_REQUEST_SUPPORT_FLAGS
+  {
+    const static int ID = P2P_COMMANDS_POOL_BASE + 7;
+
+    struct request
+    {
+      BEGIN_KV_SERIALIZE_MAP()
+      END_KV_SERIALIZE_MAP()    
+    };
+
+    struct response
+    {
+      uint32_t support_flags;
+
+      BEGIN_KV_SERIALIZE_MAP()
+        KV_SERIALIZE(support_flags)
+      END_KV_SERIALIZE_MAP()    
+    };
+  };
+  
 #endif