consensus: Implement gas costs for ZkBinary

src/consensus/fees.rs

@@ -0,0 +1,86 @@
+/* This file is part of DarkFi (https://dark.fi)
+ *
+ * Copyright (C) 2020-2023 Dyne.org foundation
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as
+ * published by the Free Software Foundation, either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+use crate::zkas::{Opcode, VarType, ZkBinary};
+
+/// Calculate the gas use for verifying a given zkas circuit.
+/// This function assumes that the zkbin was properly decoded.
+pub fn circuit_gas_use(zkbin: &ZkBinary) -> u64 {
+    let mut accumulator: u64 = 0;
+
+    // Constants each with a cost of 10
+    accumulator += 10 * zkbin.constants.len() as u64;
+
+    // Literals each with a cost of 10 (for now there's only 1 type of literal)
+    accumulator += 10 * zkbin.literals.len() as u64;
+
+    // Witnesses have cost by type
+    for witness in &zkbin.witnesses {
+        let cost = match witness {
+            VarType::Dummy => unreachable!(),
+            VarType::EcPoint => 20,
+            VarType::EcFixedPoint => unreachable!(),
+            VarType::EcFixedPointShort => unreachable!(),
+            VarType::EcFixedPointBase => unreachable!(),
+            VarType::EcNiPoint => 20,
+            VarType::Base => 10,
+            VarType::BaseArray => unreachable!(),
+            VarType::Scalar => 20,
+            VarType::ScalarArray => unreachable!(),
+            VarType::MerklePath => 40,
+            VarType::Uint32 => 10,
+            VarType::Uint64 => 10,
+            VarType::Any => 10,
+        };
+
+        accumulator += cost;
+    }
+
+    // Opcodes depending on how heavy they are
+    for opcode in &zkbin.opcodes {
+        let cost = match opcode.0 {
+            Opcode::Noop => unreachable!(),
+            Opcode::EcAdd => 30,
+            Opcode::EcMul => 30,
+            Opcode::EcMulBase => 30,
+            Opcode::EcMulShort => 30,
+            Opcode::EcMulVarBase => 30,
+            Opcode::EcGetX => 5,
+            Opcode::EcGetY => 5,
+            Opcode::PoseidonHash => 20 + 10 * opcode.1.len() as u64,
+            Opcode::MerkleRoot => 50,
+            Opcode::BaseAdd => 15,
+            Opcode::BaseMul => 15,
+            Opcode::BaseSub => 15,
+            Opcode::WitnessBase => 10,
+            Opcode::RangeCheck => 60,
+            Opcode::LessThanStrict => 100,
+            Opcode::LessThanLoose => 100,
+            Opcode::BoolCheck => 20,
+            Opcode::CondSelect => 30,
+            Opcode::ConstrainEqualBase => 10,
+            Opcode::ConstrainEqualPoint => 20,
+            Opcode::ConstrainInstance => 10,
+            Opcode::DebugPrint => 100,
+        };
+
+        accumulator += cost;
+    }
+
+    accumulator
+}

src/consensus/mod.rs

@@ -39,6 +39,9 @@ pub use state::SlotCheckpoint;
 pub mod validator;
 pub use validator::{ValidatorState, ValidatorStatePtr};
 
+/// Fee calculations
+pub mod fees;
+
 /// P2P net protocols
 pub mod proto;