HeaderLib

l1-contracts/src/core/Rollup.sol

@@ -9,7 +9,7 @@ import {IOutbox} from "./interfaces/messagebridge/IOutbox.sol";
 import {IRegistry} from "./interfaces/messagebridge/IRegistry.sol";
 
 // Libraries
-import {HeaderDecoder} from "./libraries/decoders/HeaderDecoder.sol";
+import {HeaderLib} from "./libraries/HeaderLib.sol";
 import {MessagesDecoder} from "./libraries/decoders/MessagesDecoder.sol";
 import {Hash} from "./libraries/Hash.sol";
 import {Errors} from "./libraries/Errors.sol";
@@ -56,9 +56,9 @@ contract Rollup is IRollup {
     bytes calldata _body, // TODO(#3944): this will be replaced with _txsHash once the separation is finished.
     bytes memory _proof
   ) external override(IRollup) {
-    HeaderDecoder.Header memory header = HeaderDecoder.decode(_header);
-
-    _validateHeader(header);
+    // Decode and validate header
+    HeaderLib.Header memory header = HeaderLib.decode(_header);
+    HeaderLib.validate(header, VERSION, lastBlockTs, archive);
 
     // Check if the data is available using availability oracle (change availability oracle if you want a different DA layer)
     bytes32 txsHash;
@@ -99,35 +99,6 @@ contract Rollup is IRollup {
     emit L2BlockProcessed(header.globalVariables.blockNumber);
   }
 
-  function _validateHeader(HeaderDecoder.Header memory header) internal view {
-    if (block.chainid != header.globalVariables.chainId) {
-      revert Errors.Rollup__InvalidChainId(header.globalVariables.chainId, block.chainid);
-    }
-
-    if (header.globalVariables.version != VERSION) {
-      revert Errors.Rollup__InvalidVersion(header.globalVariables.version, VERSION);
-    }
-
-    // block number already constrained by archive root check
-
-    if (header.globalVariables.timestamp > block.timestamp) {
-      revert Errors.Rollup__TimestampInFuture();
-    }
-
-    // @todo @LHerskind consider if this is too strict
-    // This will make multiple l2 blocks in the same l1 block impractical.
-    // e.g., the first block will update timestamp which will make the second fail.
-    // Could possibly allow multiple blocks if in same l1 block
-    if (header.globalVariables.timestamp < lastBlockTs) {
-      revert Errors.Rollup__TimestampTooOld();
-    }
-
-    // @todo @LHerskind Proper genesis state. If the state is empty, we allow anything for now.
-    if (archive != bytes32(0) && archive != header.lastArchive.root) {
-      revert Errors.Rollup__InvalidArchive(archive, header.lastArchive.root);
-    }
-  }
-
   function _computePublicInputHash(bytes calldata _header, bytes32 _txsHash, bytes32 _inHash)
     internal
     pure

l1-contracts/src/core/libraries/decoders/HeaderDecoder.sol → l1-contracts/src/core/libraries/HeaderLib.sol

@@ -3,13 +3,14 @@
 pragma solidity >=0.8.18;
 
 // Libraries
-import {Constants} from "../ConstantsGen.sol";
-import {Hash} from "../Hash.sol";
+import {Errors} from "./Errors.sol";
+import {Constants} from "./ConstantsGen.sol";
+import {Hash} from "./Hash.sol";
 
 /**
- * @title Header Decoder Library
+ * @title Header Library
  * @author Aztec Labs
- * @notice Decoding a L2 header
+ * @notice Decoding and validating an L2 block header
  * Concerned with readability and velocity of development not giving a damn about gas costs.
  *
  * -------------------
@@ -47,7 +48,7 @@ import {Hash} from "../Hash.sol";
  *  |                                                                                  |              | }
  *  | ---                                                                              | ---          | ---
  */
-library HeaderDecoder {
+library HeaderLib {
   struct AppendOnlyTreeSnapshot {
     bytes32 root;
     uint32 nextAvailableLeafIndex;
@@ -82,7 +83,8 @@ library HeaderDecoder {
 
   /**
    * @notice Decodes the header
-   * @param _header - The header calldata.
+   * @param _header - The header calldata
+   * @return The decoded header
    */
   function decode(bytes calldata _header) internal pure returns (Header memory) {
     require(_header.length == 376, "Invalid header length");
@@ -110,4 +112,43 @@ library HeaderDecoder {
 
     return header;
   }
+
+  /**
+   * @notice Validates the header
+   * @param _header - The decoded header
+   * @param _version - The expected version
+   * @param _lastBlockTs - The timestamp of the last block
+   * @param _archive - The expected archive root
+   */
+  function validate(Header memory _header, uint256 _version, uint256 _lastBlockTs, bytes32 _archive)
+    internal
+    view
+  {
+    if (block.chainid != _header.globalVariables.chainId) {
+      revert Errors.Rollup__InvalidChainId(_header.globalVariables.chainId, block.chainid);
+    }
+
+    if (_header.globalVariables.version != _version) {
+      revert Errors.Rollup__InvalidVersion(_header.globalVariables.version, _version);
+    }
+
+    // block number already constrained by archive root check
+
+    if (_header.globalVariables.timestamp > block.timestamp) {
+      revert Errors.Rollup__TimestampInFuture();
+    }
+
+    // @todo @LHerskind consider if this is too strict
+    // This will make multiple l2 blocks in the same l1 block impractical.
+    // e.g., the first block will update timestamp which will make the second fail.
+    // Could possibly allow multiple blocks if in same l1 block
+    if (_header.globalVariables.timestamp < _lastBlockTs) {
+      revert Errors.Rollup__TimestampTooOld();
+    }
+
+    // @todo @LHerskind Proper genesis state. If the state is empty, we allow anything for now.
+    if (_archive != bytes32(0) && _archive != _header.lastArchive.root) {
+      revert Errors.Rollup__InvalidArchive(_archive, _header.lastArchive.root);
+    }
+  }
 }

l1-contracts/test/decoders/Decoder.t.sol

@@ -11,9 +11,9 @@ import {DecoderHelper} from "./helpers/DecoderHelper.sol";
 import {HeaderDecoderHelper} from "./helpers/HeaderDecoderHelper.sol";
 import {MessagesDecoderHelper} from "./helpers/MessagesDecoderHelper.sol";
 import {TxsDecoderHelper} from "./helpers/TxsDecoderHelper.sol";
+import {HeaderLib} from "../../src/core/libraries/HeaderLib.sol";
 
 import {Decoder} from "../../src/core/libraries/decoders/Decoder.sol";
-import {HeaderDecoder} from "../../src/core/libraries/decoders/HeaderDecoder.sol";
 import {MessagesDecoder} from "../../src/core/libraries/decoders/MessagesDecoder.sol";
 import {TxsDecoder} from "../../src/core/libraries/decoders/TxsDecoder.sol";
 
@@ -59,7 +59,7 @@ contract DecoderTest is DecoderBase {
     // Header
     {
       DecoderBase.DecodedHeader memory referenceHeader = data.block.decodedHeader;
-      HeaderDecoder.Header memory header = headerHelper.decode(data.block.header);
+      HeaderLib.Header memory header = headerHelper.decode(data.block.header);
 
       // GlobalVariables
       {

l1-contracts/test/decoders/helpers/HeaderDecoderHelper.sol

@@ -2,11 +2,11 @@
 // Copyright 2023 Aztec Labs.
 pragma solidity >=0.8.18;
 
-import {HeaderDecoder} from "../../../src/core/libraries/decoders/HeaderDecoder.sol";
+import {HeaderLib} from "../../../src/core/libraries/HeaderLib.sol";
 
 contract HeaderDecoderHelper {
   // A wrapper used such that we get "calldata" and not memory
-  function decode(bytes calldata _header) public pure returns (HeaderDecoder.Header memory) {
-    return HeaderDecoder.decode(_header);
+  function decode(bytes calldata _header) public pure returns (HeaderLib.Header memory) {
+    return HeaderLib.decode(_header);
   }
 }