Transmission Interest Checks Discrepency

[boquan-fang]

Security issue notifications

Problem:

ApplicationSpace::transmission_interest() does not reflect the full set of components that Normal mode actually transmits. This means the has_transmission check in transmission.rs
can return false for the application space even when there are pending frames, leading to missed coalescing opportunities.

Application space:

s2n-quic/quic/s2n-quic-transport/src/space/application.rs

Lines 688 to 703 in f38edab

	impl<Config: endpoint::Config> transmission::interest::Provider for ApplicationSpace<Config> {
	#[inline]
	fn transmission_interest<Q: transmission::interest::Query>(
	&self,
	query: &mut Q,
	) -> transmission::interest::Result {
	self.ack_manager.transmission_interest(query)?;
	self.ping.transmission_interest(query)?;
	self.crypto_stream.transmission_interest(query)?;
	self.recovery_manager.transmission_interest(query)?;
	self.stream_manager.transmission_interest(query)?;
	self.datagram_manager.transmission_interest(query)?;
	self.dc_manager.transmission_interest(query)?;
	Ok(())
	}
	}

Normal sending mode:

s2n-quic/quic/s2n-quic-transport/src/transmission/application.rs

Lines 195 to 215 in f38edab

	impl<Config: endpoint::Config> transmission::interest::Provider for Normal<'_, Config> {
	fn transmission_interest<Q: transmission::interest::Query>(
	&self,
	query: &mut Q,
	) -> transmission::interest::Result {
	self.ack_manager.transmission_interest(query)?;
	self.handshake_status.transmission_interest(query)?;
	self.stream_manager.transmission_interest(query)?;
	self.datagram_manager.transmission_interest(query)?;
	self.local_id_registry.transmission_interest(query)?;
	self.path_manager.transmission_interest(query)?;
	self.crypto_stream.transmission_interest(query)?;
	self.recovery_manager.transmission_interest(query)?;
	self.path_manager
	.active_path()
	.transmission_interest(query)?;
	self.ping.transmission_interest(query)?;
	self.dc_manager.transmission_interest(query)?;
	Ok(())
	}
	}

We need to think about a way to refactor the logic for detecting transmission interest, so that we know the transmission interest at the space level.

Need By Date:

Solution:

Refactor the sending logic.

Requirements / Acceptance Criteria:

The application space transmission check should check for every components.

Out of scope: