wallet: add a fee multiplier

Fee can now be multiplied by 2 or 3, if users want to give
priority to their transactions. There are only three levels
to avoid too much fingerprinting. Default is 1 (minimum fee).
The default multiplier can be set by "set fee-multiplier X".

5 files changed, 66 insertions, 27 deletions

diff --git a/src/wallet/wallet2.cpp b/src/wallet/wallet2.cpp
index b6c10c0e5..a9d69627c 100644
--- a/src/wallet/wallet2.cpp
+++ b/src/wallet/wallet2.cpp
@@ -94,11 +94,12 @@ void do_prepare_file_names(const std::string& file_path, std::string& keys_file,
   }
 }
 
-uint64_t calculate_fee(const cryptonote::blobdata &blob)
+uint64_t calculate_fee(const cryptonote::blobdata &blob, uint64_t fee_multiplier)
 {
+  THROW_WALLET_EXCEPTION_IF(fee_multiplier <= 0 || fee_multiplier > 3, tools::error::invalid_fee_multiplier);
   uint64_t bytes = blob.size();
   uint64_t kB = (bytes + 1023) / 1024;
-  return kB * FEE_PER_KB;
+  return kB * FEE_PER_KB * fee_multiplier;
 }
 
 } //namespace
@@ -1054,6 +1055,9 @@ bool wallet2::store_keys(const std::string& keys_file_name, const std::string& p
   value2.SetUint(m_default_mixin);
   json.AddMember("default_mixin", value2, json.GetAllocator());
 
+  value2.SetUint(m_default_fee_multiplier);
+  json.AddMember("default_fee_multiplier", value2, json.GetAllocator());
+
   value2.SetInt(m_auto_refresh ? 1 :0);
   json.AddMember("auto_refresh", value2, json.GetAllocator());
 
@@ -1125,6 +1129,7 @@ bool wallet2::load_keys(const std::string& keys_file_name, const std::string& pa
     m_watch_only = false;
     m_always_confirm_transfers = false;
     m_default_mixin = 0;
+    m_default_fee_multiplier = 0;
     m_auto_refresh = true;
     m_refresh_type = RefreshType::RefreshDefault;
   }
@@ -1158,6 +1163,8 @@ bool wallet2::load_keys(const std::string& keys_file_name, const std::string& pa
                    || (field_store_tx_info_found && (field_store_tx_info != 0));
     GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, default_mixin, unsigned int, Uint, false);
     m_default_mixin = field_default_mixin_found ? field_default_mixin : 0;
+    GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, default_fee_multiplier, unsigned int, Uint, false);
+    m_default_fee_multiplier = field_default_fee_multiplier_found ? field_default_fee_multiplier : 0;
     GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, auto_refresh, int, Int, false);
     m_auto_refresh = !field_auto_refresh_found || (field_auto_refresh != 0);
     GET_FIELD_FROM_JSON_RETURN_ON_ERROR(json, refresh_type, int, Int, false);
@@ -2081,15 +2088,29 @@ void wallet2::commit_tx(std::vector<pending_tx>& ptx_vector)
   }
 }
 
+uint64_t wallet2::sanitize_fee_multiplier(uint64_t fee_multiplier) const
+{
+  // 0, default value used for previous fee argument, defaults to normal fee
+  if (fee_multiplier == 0)
+    return m_default_fee_multiplier > 0 ? m_default_fee_multiplier : 1;
+  // 1 to 3 are allowed as multipliers
+  if (fee_multiplier >= 1 && fee_multiplier <= 3)
+    return fee_multiplier;
+  THROW_WALLET_EXCEPTION_IF (false, error::invalid_fee_multiplier);
+  return 1;
+}
+
 //----------------------------------------------------------------------------------------------------
 // separated the call(s) to wallet2::transfer into their own function
 //
 // this function will make multiple calls to wallet2::transfer if multiple
 // transactions will be required
-std::vector<wallet2::pending_tx> wallet2::create_transactions(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee_UNUSED, const std::vector<uint8_t> extra, bool trusted_daemon)
+std::vector<wallet2::pending_tx> wallet2::create_transactions(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon)
 {
   const std::vector<size_t> unused_transfers_indices = select_available_outputs_from_histogram(fake_outs_count + 1, true, trusted_daemon);
 
+  fee_multiplier = sanitize_fee_multiplier(fee_multiplier);
+
   // failsafe split attempt counter
   size_t attempt_count = 0;
 
@@ -2120,7 +2141,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions(std::vector<crypto
 	{
 	  transfer(dst_vector, fake_outs_count, unused_transfers_indices, unlock_time, needed_fee, extra, tx, ptx, trusted_daemon);
 	  auto txBlob = t_serializable_object_to_blob(ptx.tx);
-          needed_fee = calculate_fee(txBlob);
+          needed_fee = calculate_fee(txBlob, fee_multiplier);
 	} while (ptx.fee < needed_fee);
 
         ptx_vector.push_back(ptx);
@@ -2358,7 +2379,7 @@ void wallet2::transfer_selected(const std::vector<cryptonote::tx_destination_ent
 // This system allows for sending (almost) the entire balance, since it does
 // not generate spurious change in all txes, thus decreasing the instantaneous
 // usable balance.
-std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee_UNUSED, const std::vector<uint8_t> extra, bool trusted_daemon)
+std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon)
 {
   std::vector<size_t> unused_transfers_indices;
   std::vector<size_t> unused_dust_indices;
@@ -2388,6 +2409,8 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
   // throw if attempting a transaction with no destinations
   THROW_WALLET_EXCEPTION_IF(dsts.empty(), error::zero_destination);
 
+  fee_multiplier = sanitize_fee_multiplier (fee_multiplier);
+
   // calculate total amount being sent to all destinations
   // throw if total amount overflows uint64_t
   needed_money = 0;
@@ -2499,7 +2522,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
       transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
         detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
       auto txBlob = t_serializable_object_to_blob(test_ptx.tx);
-      needed_fee = calculate_fee(txBlob);
+      needed_fee = calculate_fee(txBlob, fee_multiplier);
       available_for_fee = test_ptx.fee + test_ptx.change_dts.amount + (!test_ptx.dust_added_to_fee ? test_ptx.dust : 0);
       LOG_PRINT_L2("Made a " << txBlob.size() << " kB tx, with " << print_money(available_for_fee) << " available for fee (" <<
         print_money(needed_fee) << " needed)");
@@ -2582,7 +2605,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_2(std::vector<cryp
   return ptx_vector;
 }
 
-std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptonote::account_public_address &address, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee_UNUSED, const std::vector<uint8_t> extra, bool trusted_daemon)
+std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptonote::account_public_address &address, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon)
 {
   std::vector<size_t> unused_transfers_indices;
   std::vector<size_t> unused_dust_indices;
@@ -2598,6 +2621,8 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptono
   uint64_t needed_fee, available_for_fee = 0;
   uint64_t upper_transaction_size_limit = get_upper_tranaction_size_limit();
 
+  fee_multiplier = sanitize_fee_multiplier(fee_multiplier);
+
   // gather all our dust and non dust outputs
   for (size_t i = 0; i < m_transfers.size(); ++i)
   {
@@ -2626,7 +2651,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptono
     // get a random unspent output and use it to pay next chunk. We try to alternate
     // dust and non dust to ensure we never get with only dust, from which we might
     // get a tx that can't pay for itself
-    size_t idx = unused_transfers_indices.empty() ? pop_random_value(unused_dust_indices) : unused_dust_indices.empty() ? pop_random_value(unused_transfers_indices) : ((tx.selected_transfers.size() & 1) || accumulated_outputs > FEE_PER_KB * (upper_transaction_size_limit + 1023) / 1024) ? pop_random_value(unused_dust_indices) : pop_random_value(unused_transfers_indices);
+    size_t idx = unused_transfers_indices.empty() ? pop_random_value(unused_dust_indices) : unused_dust_indices.empty() ? pop_random_value(unused_transfers_indices) : ((tx.selected_transfers.size() & 1) || accumulated_outputs > FEE_PER_KB * fee_multiplier * (upper_transaction_size_limit + 1023) / 1024) ? pop_random_value(unused_dust_indices) : pop_random_value(unused_transfers_indices);
 
     const transfer_details &td = m_transfers[idx];
     LOG_PRINT_L2("Picking output " << idx << ", amount " << print_money(td.amount()));
@@ -2654,7 +2679,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptono
       transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
         detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
       auto txBlob = t_serializable_object_to_blob(test_ptx.tx);
-      needed_fee = calculate_fee(txBlob);
+      needed_fee = calculate_fee(txBlob, fee_multiplier);
       available_for_fee = test_ptx.fee + test_ptx.dests[0].amount + test_ptx.change_dts.amount;
       LOG_PRINT_L2("Made a " << txBlob.size() << " kB tx, with " << print_money(available_for_fee) << " available for fee (" <<
         print_money(needed_fee) << " needed)");
@@ -2667,7 +2692,7 @@ std::vector<wallet2::pending_tx> wallet2::create_transactions_all(const cryptono
         transfer_selected(tx.dsts, tx.selected_transfers, fake_outs_count, unlock_time, needed_fee, extra,
           detail::digit_split_strategy, tx_dust_policy(::config::DEFAULT_DUST_THRESHOLD), test_tx, test_ptx);
         txBlob = t_serializable_object_to_blob(test_ptx.tx);
-        needed_fee = calculate_fee(txBlob);
+        needed_fee = calculate_fee(txBlob, fee_multiplier);
         LOG_PRINT_L2("Made an attempt at a final " << ((txBlob.size() + 1023)/1024) << " kB tx, with " << print_money(test_ptx.fee) <<
           " fee  and " << print_money(test_ptx.change_dts.amount) << " change");
       } while (needed_fee > test_ptx.fee);
@@ -2994,13 +3019,13 @@ std::vector<wallet2::pending_tx> wallet2::create_unmixable_sweep_transactions(bo
 	{
 	  transfer_from(unmixable_outputs, num_outputs_per_tx, (uint64_t)0 /* unlock_time */, 0, detail::digit_split_strategy, dust_policy, extra, tx, ptx);
 	  auto txBlob = t_serializable_object_to_blob(ptx.tx);
-          needed_fee = calculate_fee(txBlob);
+          needed_fee = calculate_fee(txBlob, 1);
 
           // reroll the tx with the actual amount minus the fee
           // if there's not enough for the fee, it'll throw
 	  transfer_from(unmixable_outputs, num_outputs_per_tx, (uint64_t)0 /* unlock_time */, needed_fee, detail::digit_split_strategy, dust_policy, extra, tx, ptx);
 	  txBlob = t_serializable_object_to_blob(ptx.tx);
-          needed_fee = calculate_fee(txBlob);
+          needed_fee = calculate_fee(txBlob, 1);
 	} while (ptx.fee < needed_fee);
 
         ptx_vector.push_back(ptx);
diff --git a/src/wallet/wallet2.h b/src/wallet/wallet2.h
index c2d387acd..cecf090f4 100644
--- a/src/wallet/wallet2.h
+++ b/src/wallet/wallet2.h
@@ -88,10 +88,10 @@ namespace tools
     };
 
   private:
-    wallet2(const wallet2&) : m_run(true), m_callback(0), m_testnet(false), m_always_confirm_transfers (false), m_store_tx_info(true), m_default_mixin(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0) {}
+    wallet2(const wallet2&) : m_run(true), m_callback(0), m_testnet(false), m_always_confirm_transfers (false), m_store_tx_info(true), m_default_mixin(0), m_default_fee_multiplier(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0) {}
 
   public:
-    wallet2(bool testnet = false, bool restricted = false) : m_run(true), m_callback(0), m_testnet(testnet), m_restricted(restricted), is_old_file_format(false), m_store_tx_info(true), m_default_mixin(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0) {}
+    wallet2(bool testnet = false, bool restricted = false) : m_run(true), m_callback(0), m_testnet(testnet), m_restricted(restricted), is_old_file_format(false), m_store_tx_info(true), m_default_mixin(0), m_default_fee_multiplier(0), m_refresh_type(RefreshOptimizeCoinbase), m_auto_refresh(true), m_refresh_from_block_height(0) {}
     struct transfer_details
     {
       uint64_t m_block_height;
@@ -291,9 +291,9 @@ namespace tools
 
     void commit_tx(pending_tx& ptx_vector);
     void commit_tx(std::vector<pending_tx>& ptx_vector);
-    std::vector<pending_tx> create_transactions(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee, const std::vector<uint8_t> extra, bool trusted_daemon);
-    std::vector<wallet2::pending_tx> create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee_UNUSED, const std::vector<uint8_t> extra, bool trusted_daemon);
-    std::vector<wallet2::pending_tx> create_transactions_all(const cryptonote::account_public_address &address, const size_t fake_outs_count, const uint64_t unlock_time, const uint64_t fee_UNUSED, const std::vector<uint8_t> extra, bool trusted_daemon);
+    std::vector<pending_tx> create_transactions(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon);
+    std::vector<wallet2::pending_tx> create_transactions_2(std::vector<cryptonote::tx_destination_entry> dsts, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon);
+    std::vector<wallet2::pending_tx> create_transactions_all(const cryptonote::account_public_address &address, const size_t fake_outs_count, const uint64_t unlock_time, uint64_t fee_multiplier, const std::vector<uint8_t> extra, bool trusted_daemon);
     std::vector<pending_tx> create_unmixable_sweep_transactions(bool trusted_daemon);
     bool check_connection();
     void get_transfers(wallet2::transfer_container& incoming_transfers) const;
@@ -363,6 +363,8 @@ namespace tools
     void store_tx_info(bool store) { m_store_tx_info = store; }
     uint32_t default_mixin() const { return m_default_mixin; }
     void default_mixin(uint32_t m) { m_default_mixin = m; }
+    uint32_t get_default_fee_multiplier() const { return m_default_fee_multiplier; }
+    void set_default_fee_multiplier(uint32_t m) { m_default_fee_multiplier = m; }
     bool auto_refresh() const { return m_auto_refresh; }
     void auto_refresh(bool r) { m_auto_refresh = r; }
 
@@ -423,6 +425,7 @@ namespace tools
     uint64_t get_upper_tranaction_size_limit();
     void check_pending_txes();
     std::vector<uint64_t> get_unspent_amounts_vector();
+    uint64_t sanitize_fee_multiplier(uint64_t fee_multiplier) const;
 
     cryptonote::account_base m_account;
     std::string m_daemon_address;
@@ -455,6 +458,7 @@ namespace tools
     bool m_always_confirm_transfers;
     bool m_store_tx_info; /*!< request txkey to be returned in RPC, and store in the wallet cache file */
     uint32_t m_default_mixin;
+    uint32_t m_default_fee_multiplier;
     RefreshType m_refresh_type;
     bool m_auto_refresh;
     uint64_t m_refresh_from_block_height;
diff --git a/src/wallet/wallet_errors.h b/src/wallet/wallet_errors.h
index 184d8a2a1..ea0b6a1f5 100644
--- a/src/wallet/wallet_errors.h
+++ b/src/wallet/wallet_errors.h
@@ -56,6 +56,7 @@ namespace tools
     //       file_read_error
     //       file_save_error
     //       invalid_password
+    //       invalid_fee_multiplier
     //       refresh_error *
     //         acc_outs_lookup_error
     //         block_parse_error
@@ -226,6 +227,15 @@ namespace tools
 
       std::string to_string() const { return wallet_logic_error::to_string(); }
     };
+    struct invalid_fee_multiplier : public wallet_logic_error
+    {
+      explicit invalid_fee_multiplier(std::string&& loc)
+        : wallet_logic_error(std::move(loc), "invalid fee multiplier")
+      {
+      }
+
+      std::string to_string() const { return wallet_logic_error::to_string(); }
+    };
 
     //----------------------------------------------------------------------------------------------------
     struct invalid_pregenerated_random : public wallet_logic_error
diff --git a/src/wallet/wallet_rpc_server.cpp b/src/wallet/wallet_rpc_server.cpp
index 5be9ae5b0..01ae00fe5 100644
--- a/src/wallet/wallet_rpc_server.cpp
+++ b/src/wallet/wallet_rpc_server.cpp
@@ -232,7 +232,7 @@ namespace tools
         LOG_PRINT_L1("Requested mixin " << req.mixin << " too low for hard fork 2, using 2");
         mixin = 2;
       }
-      std::vector<wallet2::pending_tx> ptx_vector = m_wallet.create_transactions(dsts, mixin, req.unlock_time, req.fee, extra, req.trusted_daemon);
+      std::vector<wallet2::pending_tx> ptx_vector = m_wallet.create_transactions(dsts, mixin, req.unlock_time, req.fee_multiplier, extra, req.trusted_daemon);
 
       // reject proposed transactions if there are more than one.  see on_transfer_split below.
       if (ptx_vector.size() != 1)
@@ -299,9 +299,9 @@ namespace tools
       }
       std::vector<wallet2::pending_tx> ptx_vector;
       if (req.new_algorithm)
-        ptx_vector = m_wallet.create_transactions_2(dsts, mixin, req.unlock_time, req.fee, extra, req.trusted_daemon);
+        ptx_vector = m_wallet.create_transactions_2(dsts, mixin, req.unlock_time, req.fee_multiplier, extra, req.trusted_daemon);
       else
-        ptx_vector = m_wallet.create_transactions(dsts, mixin, req.unlock_time, req.fee, extra, req.trusted_daemon);
+        ptx_vector = m_wallet.create_transactions(dsts, mixin, req.unlock_time, req.fee_multiplier, extra, req.trusted_daemon);
 
       m_wallet.commit_tx(ptx_vector);
 
@@ -406,7 +406,7 @@ namespace tools
 
     try
     {
-      std::vector<wallet2::pending_tx> ptx_vector = m_wallet.create_transactions_all(dsts[0].addr, req.mixin, req.unlock_time, req.fee, extra, req.trusted_daemon);
+      std::vector<wallet2::pending_tx> ptx_vector = m_wallet.create_transactions_all(dsts[0].addr, req.mixin, req.unlock_time, req.fee_multiplier, extra, req.trusted_daemon);
 
       m_wallet.commit_tx(ptx_vector);
 
diff --git a/src/wallet/wallet_rpc_server_commands_defs.h b/src/wallet/wallet_rpc_server_commands_defs.h
index f8c04c007..3908476d6 100644
--- a/src/wallet/wallet_rpc_server_commands_defs.h
+++ b/src/wallet/wallet_rpc_server_commands_defs.h
@@ -110,7 +110,7 @@ namespace wallet_rpc
     struct request
     {
       std::list<transfer_destination> destinations;
-      uint64_t fee;
+      uint64_t fee_multiplier;
       uint64_t mixin;
       uint64_t unlock_time;
       std::string payment_id;
@@ -119,7 +119,7 @@ namespace wallet_rpc
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(destinations)
-        KV_SERIALIZE(fee)
+        KV_SERIALIZE(fee_multiplier)
         KV_SERIALIZE(mixin)
         KV_SERIALIZE(unlock_time)
         KV_SERIALIZE(payment_id)
@@ -145,7 +145,7 @@ namespace wallet_rpc
     struct request
     {
       std::list<transfer_destination> destinations;
-      uint64_t fee;
+      uint64_t fee_multiplier;
       uint64_t mixin;
       uint64_t unlock_time;
       std::string payment_id;
@@ -155,7 +155,7 @@ namespace wallet_rpc
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(destinations)
-        KV_SERIALIZE(fee)
+        KV_SERIALIZE(fee_multiplier)
         KV_SERIALIZE(mixin)
         KV_SERIALIZE(unlock_time)
         KV_SERIALIZE(payment_id)
@@ -207,7 +207,7 @@ namespace wallet_rpc
     struct request
     {
       std::string address;
-      uint64_t fee;
+      uint64_t fee_multiplier;
       uint64_t mixin;
       uint64_t unlock_time;
       std::string payment_id;
@@ -216,7 +216,7 @@ namespace wallet_rpc
 
       BEGIN_KV_SERIALIZE_MAP()
         KV_SERIALIZE(address)
-        KV_SERIALIZE(fee)
+        KV_SERIALIZE(fee_multiplier)
         KV_SERIALIZE(mixin)
         KV_SERIALIZE(unlock_time)
         KV_SERIALIZE(payment_id)