feat(kad): configurable outbound_substreams timeout

[maqi]

Description

When testing put_record_to with poor connectioin but large packet size (around 4MB), the put_record_to frequently got failed and the PutRecordToError::stats showing always failed at 10s.

"kad_event::PutRecordError::QuorumFailed", required quorum 2, stored on [], QueryStats { requests: 5, success: 0, failure: 5, start: Some(Instant { tv_sec: 121323, tv_nsec: 961187829 }), end: Some(Instant { tv_sec: 121334, tv_nsec: 188694869 }) } - ProgressStep { count: 1, last: true }

However, this timeout is not defined by request/response protocol timeout (which in our case increased to 30s already).

Further digging through the libp2p code, it turned out this timeout is actually affected by outbound_substreams timeout.
We tested with increase to 30s, do see much less put_record_to failure and QueryStats showing extended completion duration (larger than 10s, and in case of failed, to be 30s).

Hence raised this PR to provide a configurable approach of the timeout.

Notes & open questions

Ideally, the configurate shall via function call.
However, it seems it will be via the kad::ProtocolConfig , which could having issue of:

• extra traffic bytes (if ProtocolConfig to be exchanged on every connection)
• backward conpartibility, in case peer is in old version and can't parse the new ProtocolConfig

Would like a guide if there is other way to do this configure setup more user friendly.

Change checklist

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• A changelog entry has been made in the appropriate crates

[elenaf9]

Thank you for the PR @maqi.

Ideally, the configurate shall via function call.
However, it seems it will be via the kad::ProtocolConfig , which could having issue of:

• extra traffic bytes (if ProtocolConfig to be exchanged on every connection)
• backward conpartibility, in case peer is in old version and can't partse the new ProtocolConfig

Would like a guide if there is other way to do this configure setup more user friendly.

kad::ProtocolConfig is just a local config, it is never sent to remote peers (only the protocol_names property is).
So we can actually just add outbound_substream_timeout to ProtocolConfig.

[maqi]

So we can actually just add outbound_substream_timeout to ProtocolConfig.

Hi, @elenaf9,

Thx for the comment and clarification.
Got PR updated to add outbound_substream_timeout into ProtocolConfig, which allows it to be modified via function calls.

[elenaf9]

Sorry, one more comment that I missed in the last review. Rest LGTM, thanks!