Struct UdpFace 

pub struct UdpFace { /* private fields */ }

NDN face over unicast UDP.

Uses an unconnected socket with send_to / recv_from rather than a connected socket with send / recv. On macOS (and some BSDs), a connected UDP socket that receives an ICMP port-unreachable enters a permanent error state where every subsequent send() fails with EPIPE (broken pipe). The unconnected approach avoids this entirely — each datagram is independent at the kernel level.

send_to is &self-safe: UdpSocket::send_to takes &self and UDP sends are atomic at the kernel level, so no mutex is needed.

Packets larger than the configured MTU are automatically fragmented into NDNLPv2 LpPacket fragments before sending.

Implementations

impl UdpFace

pub async fn bind( local: SocketAddr, peer: SocketAddr, id: FaceId, ) -> Result<Self>

Bind to local, targeting peer for all sends.

The socket is not connected — recv_from is used and datagrams from other sources are silently discarded.

If local is 0.0.0.0:0 (or [::]:0), the socket is bound to the specific local interface that the OS routes to peer. This avoids EHOSTUNREACH on macOS when the peer is on a non-default-route subnet (e.g. a VM bridge network).

pub fn from_socket(id: FaceId, socket: UdpSocket, peer: SocketAddr) -> Self

Wrap an already-bound socket, targeting peer for all sends.

pub fn from_shared_socket( id: FaceId, socket: Arc<UdpSocket>, peer: SocketAddr, ) -> Self

Create a face that shares an existing socket (e.g. the UDP listener socket).

Replies go out from the same port the listener is bound to, so the remote peer’s connected/filtered socket accepts them. The recv() loop filters datagrams by peer address.

pub fn peer(&self) -> SocketAddr

Trait Implementations

impl Face for UdpFace

async fn recv(&self) -> Result<Bytes, FaceError>

Receive the next datagram from the peer.

Returns the raw datagram bytes (may be a bare packet or LpPacket). Fragment reassembly is handled by the pipeline’s TlvDecode stage, not here — keeping the Face layer protocol-agnostic.

Datagrams from addresses other than self.peer are silently discarded.

fn id(&self) -> FaceId

fn kind(&self) -> FaceKind

fn remote_uri(&self) -> Option<String>

Remote URI (e.g. udp4://192.168.1.1:6363). Returns None for face types that don’t have a meaningful remote endpoint.

fn local_uri(&self) -> Option<String>

Local URI (e.g. unix:///run/nfd/nfd.sock). Returns None for face types that don’t expose local binding info.

async fn send(&self, pkt: Bytes) -> Result<(), FaceError>

Send a packet. Must not block the caller; use internal buffering.

fn recv_with_addr( &self, ) -> impl Future<Output = Result<(Bytes, Option<FaceAddr>), FaceError>> + Send

Receive the next packet together with the link-layer sender address.

fn link_type(&self) -> LinkType

Link type of this face.