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@MarcosNicolau MarcosNicolau commented Jan 21, 2025

Motivation
Discovery service was becoming too big and unmanageable to be inside net.rs.

Description
This refactor splits the discovery service into its own structs and files, now the flow is:

  • Discv4 struct: handles the core logic of the discv4 protocol
    • Loading bootnodes
    • Listening for incoming connections and handling messages
    • Managing revalidations
    • Initiating lookups
  • Discv4LookupHandler: the complexity of the lookups is encapsulated in this struct.

The following improvements have also been made:

  • All Tokio tasks are now spawned using the tracker.
  • When receiving neighbors' messages, now we check we do not add ourselves to the table (which could occur occasionally).
  • Error handling has been improved, and the verification logic is now more readable, especially within message handling.

Closes None

MarcosNicolau added a commit that referenced this pull request Jan 22, 2025
allow many arguments is a temprarily fix, this will be soled in #1768
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github-actions bot commented Jan 23, 2025

| File                                                                     | Lines | Diff |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/cmd/ethrex/ethrex.rs                     | 351   | -3   |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/discv4/helpers.rs  | 23    | +23  |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/discv4/lookup.rs   | 306   | +306 |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/discv4/messages.rs | 903   | +903 |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/discv4/mod.rs      | 4     | +4   |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/discv4/server.rs   | 683   | +683 |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/kademlia.rs        | 468   | -22  |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/net.rs             | 160   | -956 |
+--------------------------------------------------------------------------+-------+------+
| /home/runner/work/ethrex/ethrex/crates/networking/p2p/rlpx/connection.rs | 543   | -8   |
+--------------------------------------------------------------------------+-------+------+

Total lines added: +1919
Total lines removed: 989
Total lines changed: 2908

Comment on lines -146 to -154
let digest = Keccak256::digest(msg.get(65..).ok_or(RLPxError::InvalidMessageLength())?);
let signature = &Signature::from_bytes(
msg.get(..64)
.ok_or(RLPxError::InvalidMessageLength())?
.into(),
)?;
let rid = RecoveryId::from_byte(*msg.get(64).ok_or(RLPxError::InvalidMessageLength())?)
.ok_or(RLPxError::InvalidRecoveryId())?;
let peer_pk = VerifyingKey::recover_from_prehash(&digest, signature, rid)?;
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I remove this because it is recovering the pubkey points bytes (node_id) from the msg, something we already do when decoding the packet (see https://github.com/lambdaclass/ethrex/blob/main/crates/networking/p2p/discv4.rs#L87-L97).

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This is great, missed to comment this on previous review!

pub(crate) type RLPxConnBroadcastSender = broadcast::Sender<(tokio::task::Id, Arc<Message>)>;

// https://github.com/ethereum/go-ethereum/blob/master/p2p/peer.go#L44
pub const P2P_MAX_MESSAGE_SIZE: usize = 2048;
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@MarcosNicolau MarcosNicolau Jan 23, 2025

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The spec doesn't mention a max size but we were using the max size of the discovery protocol, and reading geth code they define 2048 as the max packet size in rlpx, see here.

Comment on lines -278 to +275
tracker.spawn(networking);
.await.expect("Network starts");
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Note that we don't need to spawn the networking as a task. This allows us to panic if there is an err during the network startup.

@MarcosNicolau MarcosNicolau marked this pull request as ready for review January 23, 2025 22:21
@MarcosNicolau MarcosNicolau requested a review from a team as a code owner January 23, 2025 22:21
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Most comments are minor issues. And some may be wrong 😬
Good work overall!

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Nice work!

@MarcosNicolau MarcosNicolau added this pull request to the merge queue Jan 28, 2025
Merged via the queue into main with commit 0e8cf77 Jan 28, 2025
19 checks passed
@MarcosNicolau MarcosNicolau deleted the refactor/discovery branch January 28, 2025 14:36
pedrobergamini pushed a commit to pedrobergamini/ethrex that referenced this pull request Aug 24, 2025
**Motivation**
Discovery service was becoming too big and unmanageable to be inside
`net.rs`.

**Description**
This refactor splits the discovery service into its own structs and
files, now the flow is:
- `Discv4` struct: handles the core logic of the `discv4` protocol
  - Loading bootnodes
  - Listening for incoming connections and handling messages
  - Managing revalidations
  - Initiating lookups
- `Discv4LookupHandler`: the complexity of the lookups is encapsulated
in this struct.

The following improvements have also been made:
- All Tokio tasks are now spawned using the tracker.
- When receiving neighbors' messages, now we check we do not add
ourselves to the table (which could occur occasionally).
- Error handling has been improved, and the verification logic is now
more readable, especially within message handling.


Closes None
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3 participants