feat(l2): shared bridge router contract #4834

ManuelBilbao · 2025-10-09T21:14:19Z

Motivation

Shared bridge feature allows users to communicate between differents L2s seamlessly.

Description

Create a new Router contract that know each chain's contracts. A user can send a tx to the L2 bridge, with value and calldata to interact in another L2. When the batch is sent to L1, those transactions are processed in the L1 along with the batch commitment/verifying. Then, the transaction is processed in the destination L2

Related: #5016

github-actions · 2025-10-13T14:54:38Z

Lines of code report

Total lines added: 328
Total lines removed: 0
Total lines changed: 328

Detailed view

+----------------------------------------------------+-------+------+
| File                                               | Lines | Diff |
+----------------------------------------------------+-------+------+
| ethrex/cmd/ethrex/build_l2.rs                      | 402   | +5   |
+----------------------------------------------------+-------+------+
| ethrex/cmd/ethrex/l2/command.rs                    | 630   | +1   |
+----------------------------------------------------+-------+------+
| ethrex/cmd/ethrex/l2/deployer.rs                   | 1183  | +105 |
+----------------------------------------------------+-------+------+
| ethrex/crates/common/types/l2.rs                   | 3     | +1   |
+----------------------------------------------------+-------+------+
| ethrex/crates/common/types/l2/batch.rs             | 18    | +4   |
+----------------------------------------------------+-------+------+
| ethrex/crates/common/types/l2/l2_to_l2_message.rs  | 35    | +35  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/based/block_fetcher.rs            | 504   | +10  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/common/src/l1_messages.rs         | 117   | +54  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/sequencer/l1_committer.rs         | 825   | +30  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/api.rs                | 136   | +7   |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store.rs              | 344   | +18  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store_db/in_memory.rs | 361   | +13  |
+----------------------------------------------------+-------+------+
| ethrex/crates/l2/storage/src/store_db/sql.rs       | 931   | +43  |
+----------------------------------------------------+-------+------+
| ethrex/crates/networking/p2p/rlpx/l2/messages.rs   | 167   | +2   |
+----------------------------------------------------+-------+------+

Copilot

Pull Request Overview

This PR implements a shared bridge router contract that enables seamless communication between different L2 chains. Users can send transactions to one L2 bridge that will be processed on another L2, with the Router contract on L1 managing the cross-chain routing.

Key changes:

Adds L2-to-L2 message infrastructure and routing capabilities
Implements Router contract for managing chain registrations and message forwarding
Updates batch commit process to include L2-to-L2 messages in the commit signature

Reviewed Changes

Copilot reviewed 25 out of 25 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
fixtures/genesis/l2.json	Updates blob schedule configuration and contract bytecode for L2 genesis
crates/networking/p2p/rlpx/l2/messages.rs	Adds l2_to_l2_messages field to BatchSealed message structure
crates/l2/storage/src/store_db/sql.rs	Implements SQL storage for L2-to-L2 messages with new table and operations
crates/l2/storage/src/store_db/in_memory.rs	Adds in-memory storage support for L2-to-L2 messages
crates/l2/storage/src/store.rs	Updates Store interface to handle L2-to-L2 message storage and retrieval
crates/l2/storage/src/api.rs	Adds StoreEngineRollup trait methods for L2-to-L2 message operations
crates/l2/sequencer/l1_committer.rs	Updates commit function signature and batch processing to include L2-to-L2 messages
crates/l2/contracts/src/l2/interfaces/IL2ToL1Messenger.sol	Adds L2ToL2Message event and sendMessageToL2 function interface
crates/l2/contracts/src/l2/interfaces/ICommonBridgeL2.sol	Adds sendToL2 function for cross-chain messaging
crates/l2/contracts/src/l2/L2ToL1Messenger.sol	Implements L2-to-L2 message sending functionality
crates/l2/contracts/src/l2/CommonBridgeL2.sol	Adds sendToL2 function with gas burning mechanism
crates/l2/contracts/src/l1/interfaces/IRouter.sol	Defines Router contract interface for chain management and message routing
crates/l2/contracts/src/l1/interfaces/IOnChainProposer.sol	Adds L2toL2Message struct and updates commitBatch signature
crates/l2/contracts/src/l1/interfaces/ICommonBridge.sol	Updates bridge interface for shared bridge router integration
crates/l2/contracts/src/l1/Router.sol	Implements Router contract for managing chain registrations and message forwarding
crates/l2/contracts/src/l1/OnChainProposer.sol	Updates batch commit to process L2-to-L2 messages via router
crates/l2/contracts/src/l1/CommonBridge.sol	Adds shared bridge router integration and message handling
crates/l2/common/src/l1_messages.rs	Implements L2-to-L2 message extraction from transaction logs
crates/l2/based/block_fetcher.rs	Updates block fetching to extract and store L2-to-L2 messages
crates/common/types/l2/l2_to_l2_message.rs	Defines L2toL2Message struct and RLP decoding
crates/common/types/l2/batch.rs	Adds l2_to_l2_messages field to Batch struct
crates/common/types/l2.rs	Exports l2_to_l2_message module
cmd/ethrex/l2/deployer.rs	Adds Router contract deployment and chain registration
cmd/ethrex/l2/command.rs	Updates batch creation to include empty L2-to-L2 messages
cmd/ethrex/build_l2.rs	Adds Router contract to build process

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crates/l2/storage/src/store_db/sql.rs

crates/l2/storage/src/store.rs

crates/l2/storage/src/store_db/sql.rs

crates/l2/contracts/src/l1/interfaces/ICommonBridge.sol

gianbelinche · 2025-10-21T18:01:40Z

cmd/ethrex/l2/deployer.rs

+    if contract_addresses.router.is_some()
+        && register_chain(
+            &eth_client,
+            contract_addresses,
+            genesis.config.chain_id,
+            &signer,
+        )
+        .await
+        .is_err()
+    {
+        warn!("Could not register chain in shared bridge router");
+    }


I would put the register_chain inside the if to make it more readable

if contract_addresses.router.is_some() { register_chain( &eth_client, contract_addresses, genesis.config.chain_id, &signer, ) .await .inspect_err(|_| warn!("Could not register chain in shared bridge router");) }

Done 0b35959

cmd/ethrex/l2/deployer.rs

crates/l2/common/src/l1_messages.rs

cmd/ethrex/l2/command.rs

crates/l2/contracts/src/l1/CommonBridge.sol

avilagaston9

Left some comments. A how-to-run guide would be nice to have once the docs are completed.

crates/l2/contracts/src/l1/OnChainProposer.sol

crates/l2/contracts/src/l1/Router.sol

crates/l2/contracts/src/l1/interfaces/ICommonBridge.sol

avilagaston9 · 2025-10-21T19:29:46Z

crates/l2/contracts/src/l2/CommonBridgeL2.sol

+    /// @inheritdoc ICommonBridgeL2
+    function sendToL2(uint256 chainId, address to, uint256 destGasLimit, bytes calldata data) external override payable {
+        _burnGas(destGasLimit);
+        IL2ToL1Messenger(L1_MESSENGER).sendMessageToL2{value: msg.value}(chainId, msg.sender, to, destGasLimit, data);


We should consider renaming this to CROSS_CHAIN_MESSENGER or something similar.

Yes, we should debate the naming of this

crates/l2/sequencer/l1_committer.rs

Create router contract

caea86a

ManuelBilbao self-assigned this Oct 9, 2025

github-actions bot added the L2 Rollup client label Oct 9, 2025

github-project-automation bot added this to ethrex_l2 Oct 9, 2025

ManuelBilbao added 2 commits October 10, 2025 09:09

Add router feature to contracts

2284147

Add router to deployer

d3d9985

ManuelBilbao added 19 commits October 14, 2025 19:50

Update contracts

a023188

Send messages across L2s

109e234

Merge branch 'main' into shared_bridge_router

508438a

Fix merge

f104f5c

Burn gas in src L2

018a63d

Merge branch 'main' into shared_bridge_router

dfdb8ea

Change contracts flow

a57fead

Add contracts docs

21ad3aa

Improve documentation

1901b1d

Revert changes

1a99f05

Add docs

c220c3e

Move router contract to main path

d937327

Refactor deployer

19df3e8

Merge branch 'main' into shared_bridge_router

81fbdd9

Fix event signature

78011eb

Update genesis L2

0bc4f04

Add L2toL2Messages to store

b102114

Implement L2toL2Messages in block fetcher

f127bdc

Implement get L2->L2 messages for SQL store

d55eed5

ManuelBilbao marked this pull request as ready for review October 17, 2025 16:09

ManuelBilbao requested review from a team and jrchatruc as code owners October 17, 2025 16:09

Copilot AI review requested due to automatic review settings October 17, 2025 16:09

Copilot AI reviewed Oct 17, 2025

View reviewed changes

ManuelBilbao added 5 commits October 17, 2025 13:15

Remove unwraps

12bc29c

Merge branch 'main' into shared_bridge_router

29cac02

Fix sql

b5b3a76

Fix wording

f3f083a

Merge branch 'main' into shared_bridge_router

41b8adc

gianbelinche reviewed Oct 21, 2025

View reviewed changes

Add preliminar shared bridge documentation

7c826ed

tomip01 reviewed Oct 21, 2025

View reviewed changes

avilagaston9 reviewed Oct 21, 2025

View reviewed changes

ManuelBilbao added 8 commits October 22, 2025 15:04

Merge branch 'main' into shared_bridge_router

af2558d

Apply format suggestion

0b35959

Apply format suggestion

17e3f1f

Rename shared bridge variable

02d20de

Rename message_hashes field

54010cf

Fix missing rename

36463e3

Fix tests

c806c25

Unlink router and OCP

8f95d80

tomip01 approved these changes Oct 22, 2025

View reviewed changes

avilagaston9 approved these changes Oct 22, 2025

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ManuelBilbao linked an issue Oct 23, 2025 that may be closed by this pull request

[Tracking] Shared Bridge #5016

Open

ManuelBilbao removed a link to an issue Oct 23, 2025

[Tracking] Shared Bridge #5016

Open

Fix deposit when no calldata

089e3df

gianbelinche approved these changes Oct 23, 2025

View reviewed changes

ManuelBilbao added 5 commits October 23, 2025 15:10

Merge branch 'main' into shared_bridge_router

486e5aa

Merge branch 'main' into shared_bridge_router

df9c9d8

Merge branch 'main' into shared_bridge_router

425dbd7

Fix: store L2->L2 txs when sealing batch

9be647d

Fix based commitment transaction

5329629

feat(l2): shared bridge router contract #4834

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feat(l2): shared bridge router contract #4834

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Pull Request Overview

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gianbelinche Oct 21, 2025

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ManuelBilbao commented Oct 9, 2025 •

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