Struct xsk_rs::umem::Umem

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pub struct Umem { /* private fields */ }

Expand description

A region of virtual contiguous memory divided into equal-sized frames. It provides the underlying working memory for an AF_XDP Socket.

Implementations

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impl Umem

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pub fn new(
 config: UmemConfig,
 frame_count: NonZeroU32,
 use_huge_pages: bool
) -> Result<(Self, Vec<FrameDesc>), UmemCreateError>

Create a new Umem instance backed by an anonymous memory mapped region.

Setting use_huge_pages to true will instructed mmap() to allocate the underlying memory using huge pages. If you are getting errors as a result of this, check that the HugePages_Total setting is non-zero when you run cat /proc/meminfo.

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pub unsafe fn frame(&self, desc: &FrameDesc) -> (Headroom<'_>, Data<'_>)

The headroom and packet data segments of the Umem frame pointed at by desc. Contents are read-only.

Safety

desc must correspond to a frame belonging to this Umem. Passing the descriptor of another Umem is very likely to result in incorrect memory access, by either straddling frames or accessing memory outside the underlying Umem area.

Furthermore, the memory region accessed must not be mutably accessed anywhere else at the same time, either in userspace or by the kernel. To ensure this, care should be taken not to use the frame after submission to either the TxQueue or FillQueue until received over the CompQueue or RxQueue respectively.

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pub unsafe fn headroom(&self, desc: &FrameDesc) -> Headroom<'_>

The headroom segment of the Umem frame pointed at by desc. Contents are read-only.

Safety

See frame.

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pub unsafe fn data(&self, desc: &FrameDesc) -> Data<'_>

The data segment of the Umem frame pointed at by desc. Contents are read-only.

Safety

See frame.

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pub unsafe fn frame_mut<'a>(
&'a self,
desc: &'a mut FrameDesc
) -> (HeadroomMut<'a>, DataMut<'a>)

The headroom and packet data segments of the Umem frame pointed at by desc. Contents are writeable.

Safety

desc must correspond to a frame belonging to this Umem. Passing the descriptor of another Umem is very likely to result in incorrect memory access, by either straddling frames or accessing memory outside the underlying Umem area.

Furthermore, the memory region accessed must not be mutably or immutably accessed anywhere else at the same time, either in userspace or by the kernel. To ensure this, care should be taken not to use the frame after submission to either the TxQueue or FillQueue until received over the CompQueue or RxQueue respectively.

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