swarm/: Limit negotiating inbound substreams per connection #2697
+62
−2
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This limit is shared across all `ConnectionHandler`s on a single connection. It only enforces a limit on the number of negotiating substreams. Once negotiated a `ConnectionHandler` manages the lifecycle of the substream and has to enforce limits themselves.
thomaseizinger
approved these changes
Jun 7, 2022
| @@ -243,6 +247,11 @@ where | |||
| ) { | |||
| match endpoint { | |||
| SubstreamEndpoint::Listener => { | |||
| if self.negotiating_in.len() == MAX_NUM_NEGOTIATING_IN { | |||
There was a problem hiding this comment.
Instead of doing this check here, we could create a wrapper around FuturesUnordered that enforces a limit on the number of concurrent futures. This would foster reuse and actually enforce this limit. At the moment, there is a risk that this check is circumvented in case the FuturesUnordered is modified in a different place without this check.
There was a problem hiding this comment.
👍 for the reusable abstraction, though I would much rather like to remove the entire upgrade mechanism for substreams in the future.
| @@ -35,6 +35,10 @@ use libp2p_core::{ | |||
| }; | |||
| use std::{error, fmt, pin::Pin, task::Context, task::Poll, time::Duration}; | |||
|
|
|||
| /// The maximum number of incoming streams concurrently negotiated. Streams are | |||
| /// dropped and thus reset. | |||
| const MAX_NUM_NEGOTIATING_IN: usize = 128; | |||
There was a problem hiding this comment.
How was this number chosen?
mxinden
commented
Jun 8, 2022
1 task
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Description
This limit is shared across all
ConnectionHandlers on a single connection. Itonly enforces a limit on the number of negotiating substreams. Once negotiated a
ConnectionHandlermanages the lifecycle of the substream and has to enforcelimits themselves.
Links to any relevant issues
Open Questions
Change checklist