ndn_strategy/
strategy.rs

1use crate::context::StrategyContext;
2use ndn_packet::Name;
3use ndn_transport::ForwardingAction;
4
5/// The forwarding strategy trait.
6///
7/// A strategy is a pure decision function — it reads state through
8/// `StrategyContext` but cannot modify forwarding tables directly.
9/// Autonomous behaviour (probing, discovery) is done via the `Probe` channel
10/// on `StrategyContext`.
11pub trait Strategy: Send + Sync + 'static {
12    /// Canonical name identifying this strategy.
13    fn name(&self) -> &Name;
14
15    /// Synchronous fast path for forwarding decisions.
16    ///
17    /// Strategies whose `after_receive_interest` is fully synchronous should
18    /// override this to return `Some(actions)`, avoiding the `Box::pin` heap
19    /// allocation in the `ErasedStrategy` wrapper.
20    ///
21    /// Returns `None` (default) to fall through to the async path.
22    fn decide(&self, _ctx: &StrategyContext) -> Option<smallvec::SmallVec<[ForwardingAction; 2]>> {
23        None
24    }
25
26    /// Called when an Interest arrives and needs a forwarding decision.
27    fn after_receive_interest(
28        &self,
29        ctx: &StrategyContext,
30    ) -> impl std::future::Future<Output = smallvec::SmallVec<[ForwardingAction; 2]>> + Send;
31
32    /// Called when Data arrives and needs to be forwarded to consumers.
33    fn after_receive_data(
34        &self,
35        ctx: &StrategyContext,
36    ) -> impl std::future::Future<Output = smallvec::SmallVec<[ForwardingAction; 2]>> + Send;
37
38    /// Called when a PIT entry times out. Default: suppress (let the entry die).
39    fn on_interest_timeout(
40        &self,
41        _ctx: &StrategyContext,
42    ) -> impl std::future::Future<Output = ForwardingAction> + Send {
43        async { ForwardingAction::Suppress }
44    }
45
46    /// Called when a Nack arrives on an out-record face.
47    fn on_nack(
48        &self,
49        _ctx: &StrategyContext,
50        _reason: ndn_transport::NackReason,
51    ) -> impl std::future::Future<Output = ForwardingAction> + Send {
52        async { ForwardingAction::Suppress }
53    }
54}
ndn_strategy/strategy.rs

ndn_strategy/
strategy.rs
