Module af_xdp 

AF_XDP (XSK) kernel-bypass driver and UMEM shared memory pool.

Provides zero-copy memory buffers (UmemPool) and ring buffer descriptors (FillRing, CompletionRing) for kernel-bypass packet I/O.

Low-level libc XSK/XDP structures and unsafe memory mappings are quarantined within this module, with explicit // SAFETY: justifications on all unsafe blocks.

Structs

CompletionRing

Ring buffer for UMEM completion descriptors (chunk addresses pushed by kernel/NIC after TX completion).

FillRing

Ring buffer for UMEM fill descriptors (chunk addresses pushed by userspace for the kernel/NIC to fill).

RxRing

Circular descriptor ring for AF_XDP RX packets.

TxRing

Circular descriptor ring for AF_XDP TX packets.

UmemPool

Pre-allocated page-aligned shared memory pool for AF_XDP kernel-bypass I/O.

UmemPoolConfig

Configuration parameters for allocating an AF_XDP UmemPool.

UmemSlab

Dedicated per-core / per-queue UMEM chunk slab for lock-free AF_XDP multi-worker scaling.

XskDesc

Descriptor for AF_XDP packets in RX and TX rings.

XskSocket

AF_XDP socket with three-tier opportunistic fallback engine.

Enums

XskBindMode

The operational mode for AF_XDP binding, with automatic fallback.

Constants

ENOTSUPP

Linux internal errno for unsupported operation (ENOTSUPP).

UMEM_CHUNK_SIZE

Default UMEM chunk size in bytes (2 KiB aligns with MTU 1500 + wire overhead).

UMEM_RING_SIZE

Default ring size in descriptors (must be a power of two).

XDP_COPY

Flag for copy-mode bind in AF_XDP (XDP_COPY).

XDP_ZEROCOPY

Alias for XDP_ZERO_COPY matching kernel naming XDP_ZEROCOPY.

XDP_ZERO_COPY

Flag for zero-copy mode bind in AF_XDP (XDP_ZEROCOPY).