Struct IfaceMap 

pub struct IfaceMap { /* private fields */ }

Refreshable cache of IPv4 interfaces.

Cheap to clone (Arc-shared internal state). Spawned tasks share a single map and refresh on demand via IfaceMap::refresh_if_stale.

Implementations

impl IfaceMap

pub fn new() -> Self

Build a fresh map by enumerating interfaces now.

pub fn refresh(&self)

Force-refresh the snapshot.

pub fn refresh_if_stale(&self, max_age: Duration) -> Duration

Refresh if the snapshot is older than max_age. Returns the snapshot age before any refresh.

pub fn spawn_refresh(&self, period: Duration) -> TaskHandle<()>

Spawn a background tokio task that refreshes the snapshot every period until the returned tokio::task::JoinHandle is aborted. Mirrors pvxs IfMapDaemon (evhelper.cpp:715-758) which polls every 15 s.

Returns the handle so callers that own the runtime can store it for shutdown; dropping it does NOT cancel the task — abort it explicitly. Idempotent: multiple background refreshers on the same map cost extra wakeups but are harmless.

Without this, dynamic infrastructure (DHCP renewals changing the broadcast address; K8s pod network re-attach; VM live migration; cable hot-plug) leaves the snapshot stale, and any sender that derives a broadcast destination from the snapshot ends up sending to the wrong subnet.

pub fn all(&self) -> Vec<IfaceInfo>

Snapshot of all IPv4 interfaces. Includes loopback unless callers filter via IfaceInfo::up_non_loopback.

pub fn up_non_loopback(&self) -> Vec<IfaceInfo>

Snapshot of up, non-loopback IPv4 interfaces — the typical fanout target list for SEARCH/beacon traffic.

pub fn by_index(&self, index: u32) -> Option<IfaceInfo>

Look up an interface by its kernel index. Returns None when the index isn’t known to this snapshot — caller may want to refresh() and retry once.

pub fn route_to(&self, dest: Ipv4Addr) -> Option<IfaceInfo>

Pick the interface index that should originate traffic destined for dest. The selection rules (in priority order):

1. Subnet match — dest falls within an interface’s (ip, netmask). Returned when present.
2. Broadcast match — dest equals an interface’s subnet broadcast.
3. Loopback — 127.0.0.0/8 → loopback interface.
4. Default route — an interface with a 0.0.0.0 netmask matches any destination; used only as a fallback so it never shadows a specific subnet match.
5. Otherwise None — caller treats this as “no per-NIC pinning, let the OS route”. For limited broadcast and multicast destinations the caller fanouts across all interfaces explicitly.

Trait Implementations

impl Clone for IfaceMap

fn clone(&self) -> IfaceMap

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Default for IfaceMap

fn default() -> Self

Returns the “default value” for a type.