From 721eb95f941643c891b241068398316267c7a9b0 Mon Sep 17 00:00:00 2001
From: Bohdan Ohorodnii <limposfeed@gmail.com>
Date: Mon, 14 Oct 2024 13:33:51 +0300
Subject: [PATCH] feat: add support for `keccak` syscall

---
 crates/blockifier/cairo_native                |  2 +-
 .../src/execution/native/syscall_handler.rs   | 52 +++++++++++++++++--
 .../syscalls/syscall_tests/keccak.rs          |  6 ++-
 3 files changed, 54 insertions(+), 6 deletions(-)

diff --git a/crates/blockifier/cairo_native b/crates/blockifier/cairo_native
index 26e1c67966..ab478323d6 160000
--- a/crates/blockifier/cairo_native
+++ b/crates/blockifier/cairo_native
@@ -1 +1 @@
-Subproject commit 26e1c67966b93acd8b183823aae6f3e4fdc5c78c
+Subproject commit ab478323d6aee5e0424712bbde98de443b8cc72f
diff --git a/crates/blockifier/src/execution/native/syscall_handler.rs b/crates/blockifier/src/execution/native/syscall_handler.rs
index ac31b39b4b..b2c080ba1a 100644
--- a/crates/blockifier/src/execution/native/syscall_handler.rs
+++ b/crates/blockifier/src/execution/native/syscall_handler.rs
@@ -17,7 +17,11 @@ use starknet_types_core::felt::Felt;
 use crate::execution::call_info::{CallInfo, OrderedEvent, OrderedL2ToL1Message, Retdata};
 use crate::execution::entry_point::{CallEntryPoint, EntryPointExecutionContext};
 use crate::execution::native::utils::encode_str_as_felts;
-use crate::execution::syscalls::hint_processor::{SyscallCounter, OUT_OF_GAS_ERROR};
+use crate::execution::syscalls::hint_processor::{
+    SyscallCounter,
+    INVALID_INPUT_LENGTH_ERROR,
+    OUT_OF_GAS_ERROR,
+};
 use crate::execution::syscalls::SyscallSelector;
 use crate::state::state_api::State;
 
@@ -96,7 +100,6 @@ impl<'state> NativeSyscallHandler<'state> {
 
     /// Handles all gas-related logics and additional metadata such as `SyscallCounter`. In native,
     /// we need to explicitly call this method at the beginning of each syscall.
-    #[allow(dead_code)]
     fn pre_execute_syscall(
         &mut self,
         remaining_gas: &mut u128,
@@ -218,8 +221,49 @@ impl<'state> StarknetSyscallHandler for &mut NativeSyscallHandler<'state> {
         todo!("Implement send_message_to_l1 syscall.");
     }
 
-    fn keccak(&mut self, _input: &[u64], _remaining_gas: &mut u128) -> SyscallResult<U256> {
-        todo!("Implement keccak syscall.");
+    fn keccak(&mut self, input: &[u64], remaining_gas: &mut u128) -> SyscallResult<U256> {
+        self.pre_execute_syscall(
+            remaining_gas,
+            SyscallSelector::Keccak,
+            self.context.gas_costs().keccak_gas_cost,
+        )?;
+
+        const KECCAK_FULL_RATE_IN_WORDS: usize = 17;
+
+        let input_length = input.len();
+        let (n_rounds, remainder) = num_integer::div_rem(input_length, KECCAK_FULL_RATE_IN_WORDS);
+
+        if remainder != 0 {
+            // In VM this error is wrapped into `SyscallExecutionError::SyscallError`
+            return Err(vec![Felt::from_hex(INVALID_INPUT_LENGTH_ERROR).unwrap()]);
+        }
+
+        // TODO(Ori, 1/2/2024): Write an indicative expect message explaining why the conversion
+        // works.
+        let n_rounds_as_u128 = u128::try_from(n_rounds).expect("Failed to convert usize to u128.");
+        let gas_cost =
+            n_rounds_as_u128 * u128::from(self.context.gas_costs().keccak_round_cost_gas_cost);
+
+        if gas_cost > *remaining_gas {
+            // In VM this error is wrapped into `SyscallExecutionError::SyscallError`
+            return Err(vec![Felt::from_hex(OUT_OF_GAS_ERROR).unwrap()]);
+        }
+        *remaining_gas -= gas_cost;
+
+        self.increment_syscall_count_by(&SyscallSelector::Keccak, n_rounds);
+
+        let mut state = [0u64; 25];
+        for chunk in input.chunks(KECCAK_FULL_RATE_IN_WORDS) {
+            for (i, val) in chunk.iter().enumerate() {
+                state[i] ^= val;
+            }
+            keccak::f1600(&mut state)
+        }
+
+        Ok(U256 {
+            hi: u128::from(state[2]) | (u128::from(state[3]) << 64),
+            lo: u128::from(state[0]) | (u128::from(state[1]) << 64),
+        })
     }
 
     fn secp256k1_new(
diff --git a/crates/blockifier/src/execution/syscalls/syscall_tests/keccak.rs b/crates/blockifier/src/execution/syscalls/syscall_tests/keccak.rs
index 3327f40c40..18cef7001a 100644
--- a/crates/blockifier/src/execution/syscalls/syscall_tests/keccak.rs
+++ b/crates/blockifier/src/execution/syscalls/syscall_tests/keccak.rs
@@ -11,6 +11,10 @@ use crate::test_utils::initial_test_state::test_state;
 use crate::test_utils::{trivial_external_entry_point_new, CairoVersion, BALANCE};
 
 #[test_case(FeatureContract::TestContract(CairoVersion::Cairo1), 254910; "VM")]
+#[cfg_attr(
+    feature = "cairo_native",
+    test_case(FeatureContract::TestContract(CairoVersion::Native), 265110; "Native")
+)]
 fn test_keccak(test_contract: FeatureContract, expected_gas: u64) {
     let chain_info = &ChainInfo::create_for_testing();
     let mut state = test_state(chain_info, BALANCE, &[(test_contract, 1)]);
@@ -22,7 +26,7 @@ fn test_keccak(test_contract: FeatureContract, expected_gas: u64) {
         ..trivial_external_entry_point_new(test_contract)
     };
 
-    assert_eq!(
+    pretty_assertions::assert_eq!(
         entry_point_call.execute_directly(&mut state).unwrap().execution,
         CallExecution { gas_consumed: expected_gas, ..CallExecution::from_retdata(retdata![]) }
     );