Struct DefaultNatStrategy 

pub struct DefaultNatStrategy { /* private fields */ }

Default NAT strategy using real STUN probing, UPnP, and bridge relay.

Implements the tier selection algorithm from spec 10.12.8:

1. Probe NAT type via STUN.
2. Attempt Tier 1 (UPnP/NAT-PMP) if a [PortMapper] is configured. Run reachability self-test on the mapped address (spec 10.12.2 step 4).
3. If Tier 1 fails and NAT is non-symmetric, attempt Tier 2 (STUN address). Run reachability self-test on the STUN-discovered address (spec 10.12.3).
4. If Tier 2 fails or NAT is symmetric, attempt Tier 3 (bridge relay).

The reachability self-test (SCP-242) sends a STUN Binding Request from the SAME socket that holds the NAT mapping to a STUN server intermediary. If the server confirms the expected external address, the mapping is valid.

Uses NatProber for STUN probing, PortMapper for UPnP, and ReachabilityProbe for self-test.

Implementations

impl DefaultNatStrategy

pub fn new(stun_server: Option<String>, bridge_relay: Option<String>) -> Self

Creates a new default NAT strategy with optional overrides.

pub fn with_port_mapper(self, mapper: Arc<dyn PortMapper>) -> Self

Sets the UPnP/NAT-PMP port mapper for Tier 1 (spec 10.12.2).

pub fn with_reachability_probe(self, probe: Arc<dyn ReachabilityProbe>) -> Self

Sets the reachability probe for self-test verification (SCP-242).

If not set, a DefaultReachabilityProbe is constructed from the first STUN endpoint at probe time.

Trait Implementations

impl NatStrategy for DefaultNatStrategy

fn select_tier( &self, relay_port: u16, ) -> Pin<Box<dyn Future<Output = Result<ReachabilityTier, NodeError>> + Send + '_>>

Probes NAT type and selects the best reachability tier.