RLP encode legacy transactions without to address (#9)

flashbots · Jan 5, 2024 · 2485457 · 2485457
1 parent ed5306e
commit 2485457
Show file tree

Hide file tree

Showing 2 changed files with 39 additions and 7 deletions.
diff --git a/src/Transactions.sol b/src/Transactions.sol
@@ -28,7 +28,12 @@ library Transactions {
         items[0] = RLPWriter.writeUint(txStruct.nonce);
         items[1] = RLPWriter.writeUint(txStruct.gasPrice);
         items[2] = RLPWriter.writeUint(txStruct.gas);
-        items[3] = RLPWriter.writeAddress(txStruct.to);
+
+        if (txStruct.to == address(0)) {
+            items[3] = RLPWriter.writeBytes(bytes(""));
+        } else {
+            items[3] = RLPWriter.writeAddress(txStruct.to);
+        }
         items[4] = RLPWriter.writeUint(txStruct.value);
         items[5] = RLPWriter.writeBytes(txStruct.data);
         items[6] = RLPWriter.writeBytes(txStruct.v);
@@ -47,7 +52,13 @@ library Transactions {
         txStruct.nonce = uint64(ls[0].toUint());
         txStruct.gasPrice = uint64(ls[1].toUint());
         txStruct.gas = uint64(ls[2].toUint());
-        txStruct.to = ls[3].toAddress();
+
+        if (ls[3].toRlpBytes().length == 1) {
+            txStruct.to = address(0);
+        } else {
+            txStruct.to = ls[3].toAddress();
+        }
+
         txStruct.value = uint64(ls[4].toUint());
         txStruct.data = ls[5].toBytes();
         txStruct.v = ls[6].toBytes();

diff --git a/test/Transactions.sol → test/Transactions.t.sol b/test/Transactions.sol → test/Transactions.t.sol
@@ -8,7 +8,7 @@ contract TestTransactions is Test {
     using Transactions for *;
 
     function testLegacyTransactionRLPEncoding() public {
-        Transactions.Legacy memory legacyTxn0 = Transactions.Legacy({
+        Transactions.Legacy memory txnWithToAddress = Transactions.Legacy({
             to: address(0x095E7BAea6a6c7c4c2DfeB977eFac326aF552d87),
             gas: 50000,
             gasPrice: 10,
@@ -21,17 +21,38 @@ contract TestTransactions is Test {
             s: abi.encodePacked(hex"8a8fae537ce25ed8cb5af9adac3f141af69bd515bd2ba031522df09b97dd72b1")
         });
 
-        bytes memory rlp = Transactions.encodeRLP(legacyTxn0);
-
         bytes memory expected = abi.encodePacked(
             hex"f85f800a82c35094095e7baea6a6c7c4c2dfeb977efac326af552d870a801ba09bea4c4daac7c7c52e093e6a4c35dbbcf8856f1af7b059ba20253e70848d094fa08a8fae537ce25ed8cb5af9adac3f141af69bd515bd2ba031522df09b97dd72b1"
         );
-        assertEq0(rlp, expected);
+        _testLegacyTransaction(txnWithToAddress, expected);
+
+        Transactions.Legacy memory txnWithoutToAddress = Transactions.Legacy({
+            to: address(0),
+            gas: 50000,
+            gasPrice: 10,
+            value: 10,
+            nonce: 1,
+            data: abi.encodePacked(hex"02"),
+            chainId: 0,
+            v: abi.encodePacked(hex"1b"),
+            r: abi.encodePacked(hex"754a33a9c37cfcf61cd61939fd93f5fe194b7d1ee6ef07490e8c880f3bd0d87d"),
+            s: abi.encodePacked(hex"715bd50fa2c24e2ce0ea595025a44a39ac238558882f9f07dd885ddc51839419")
+        });
+
+        expected = abi.encodePacked(
+            hex"f84b010a82c350800a021ba0754a33a9c37cfcf61cd61939fd93f5fe194b7d1ee6ef07490e8c880f3bd0d87da0715bd50fa2c24e2ce0ea595025a44a39ac238558882f9f07dd885ddc51839419"
+        );
+        _testLegacyTransaction(txnWithoutToAddress, expected);
+    }
+
+    function _testLegacyTransaction(Transactions.Legacy memory legacyTxn, bytes memory expectedRlp) public {
+        bytes memory rlp = Transactions.encodeRLP(legacyTxn);
+        assertEq0(rlp, expectedRlp);
 
         Transactions.Legacy memory legacyTxn1 = Transactions.decodeRLP(rlp);
 
         // re-encode to validate that the decoding was correct
         bytes memory rlp1 = Transactions.encodeRLP(legacyTxn1);
-        assertEq0(rlp1, expected);
+        assertEq0(rlp1, expectedRlp);
     }
 }