Tx data checks using tracing

README.md

@@ -1 +1,33 @@
-# pepc-boost-testing
+# Checking tx data using geth style call traces
+
+## Introduction
+
+Let's say we have an ethereum tx and we want to figure out whether this tx performs a Weth/Dai swap on Uniswap V2. One way to achieve this is by
+checking if the `To` address of the tx is to the Uniswap V2 Weth/Dai pool and then parsing the `Data` field of the tx to see if it matches the
+signature of the `swap` function of the Uniswap V2 Weth/Dai pool contract. This works for simple txs made by EOA accounts, but what if the tx is
+made by a contract? In this case, the `To` address of the tx will be to the contract address, and the `Data` field of the tx will be the ABI
+encoded function call to the contract. We cannot parse the `Data` field of the tx to see if it matches the signature of the `swap` function of
+the Uniswap V2 Weth/Dai pool contract. 
+
+To acheive this, we can use the `debug_traceCall` RPC call of geth to get the call traces of the tx. The call traces will contain the multiple traces of the
+tx, and we can parse the `input` field of the traces to see if it matches the signature of the `swap` function of the Uniswap V2 Weth/Dai pool contract.
+We can think of the calltracer breaking the tx down into the individual sub-txs performed. One of the individual sub-txs will be the `swap` function
+call to the Uniswap V2 Weth/Dai pool contract.
+
+## Running this example
+
+This example uses a Kurtosis devnet setup. You can refer to https://github.com/kurtosis-tech/eth2-package to setup kurtosis and the devnet.
+
+Once you have the devnet setup, please enter the EC url in the `constants/addresses.go` file. You can then run the example using the following command:
+
+```bash
+go run main.go
+```
+
+The files in `contracts` directory are generated using abigen(https://geth.ethereum.org/docs/tools/abigen). The `update-abis.sh` script has more details on
+how the files were generated.
+
+The abis in `abis` directory are picked up from https://github.com/flashbots/mev-flood. You can compile the contracts in the `mev-flood` repo by following the README file
+
+The bulk of the logic is in `util/tracing.go`. The logic includes making the `debug_traceCall` and parsing the traces to see if the tx performs a Weth/Dai swap on Uniswap V2.
+We use the abi generated from the `mev-flood` repo to parse the `input` field of the traces.

abis/UniswapFactory.json

@@ -0,0 +1,193 @@
+[
+  {
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "_feeToSetter",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "nonpayable",
+    "type": "constructor"
+  },
+  {
+    "anonymous": false,
+    "inputs": [
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "token0",
+        "type": "address"
+      },
+      {
+        "indexed": true,
+        "internalType": "address",
+        "name": "token1",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "address",
+        "name": "pair",
+        "type": "address"
+      },
+      {
+        "indexed": false,
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "name": "PairCreated",
+    "type": "event"
+  },
+  {
+    "constant": true,
+    "inputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "name": "allPairs",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [],
+    "name": "allPairsLength",
+    "outputs": [
+      {
+        "internalType": "uint256",
+        "name": "",
+        "type": "uint256"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": false,
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "tokenA",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "tokenB",
+        "type": "address"
+      }
+    ],
+    "name": "createPair",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "pair",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [],
+    "name": "feeTo",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [],
+    "name": "feeToSetter",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": true,
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      },
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "name": "getPair",
+    "outputs": [
+      {
+        "internalType": "address",
+        "name": "",
+        "type": "address"
+      }
+    ],
+    "payable": false,
+    "stateMutability": "view",
+    "type": "function"
+  },
+  {
+    "constant": false,
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "_feeTo",
+        "type": "address"
+      }
+    ],
+    "name": "setFeeTo",
+    "outputs": [],
+    "payable": false,
+    "stateMutability": "nonpayable",
+    "type": "function"
+  },
+  {
+    "constant": false,
+    "inputs": [
+      {
+        "internalType": "address",
+        "name": "_feeToSetter",
+        "type": "address"
+      }
+    ],
+    "name": "setFeeToSetter",
+    "outputs": [],
+    "payable": false,
+    "stateMutability": "nonpayable",
+    "type": "function"
+  }
+]