Struct MapHandle

pub struct MapHandle { /* private fields */ }

A handle to a map. Handles can be duplicated and dropped.

While possible to created directly, in many cases it is useful to create such a handle from an existing Map:

let map: &Map = get_map();
let map_handle = MapHandle::try_from(map).unwrap();

Some methods require working with raw bytes. You may find libraries such as plain helpful.

Implementations

impl MapHandle

pub fn create<T: AsRef<OsStr>>( map_type: MapType, name: Option<T>, key_size: u32, value_size: u32, max_entries: u32, opts: &bpf_map_create_opts, ) -> Result<Self>

Create a bpf map whose data is not managed by libbpf.

pub fn from_pinned_path<P: AsRef<Path>>(path: P) -> Result<Self>

Open a previously pinned map from its path.

Panics

If the path contains null bytes.

pub fn from_map_id(id: u32) -> Result<Self>

Open a loaded map from its map id.

pub fn freeze(&self) -> Result<()>

Freeze the map as read-only from user space.

Entries from a frozen map can no longer be updated or deleted with the bpf() system call. This operation is not reversible, and the map remains immutable from user space until its destruction. However, read and write permissions for BPF programs to the map remain unchanged.

pub fn pin<P: AsRef<Path>>(&mut self, path: P) -> Result<()>

Pin this map to bpffs.

pub fn unpin<P: AsRef<Path>>(&mut self, path: P) -> Result<()>

Unpin this map from bpffs.

Trait Implementations

impl AsFd for MapHandle

fn as_fd(&self) -> BorrowedFd<'_>

Borrows the file descriptor.

impl Debug for MapHandle

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl MapCore for MapHandle

fn name(&self) -> &OsStr

Retrieve the map’s name.

fn map_type(&self) -> MapType

Retrieve type of the map.

fn key_size(&self) -> u32

Retrieve the size of the map’s keys.

fn value_size(&self) -> u32

Retrieve the size of the map’s values.

fn info(&self) -> Result<MapInfo>

Fetch extra map information

fn keys(&self) -> MapKeyIter<'_>

Returns an iterator over keys in this map

fn lookup(&self, key: &[u8], flags: MapFlags) -> Result<Option<Vec<u8>>>

Returns map value as Vec of u8.

fn lookup_bloom_filter(&self, value: &[u8]) -> Result<bool>

Returns if the given value is likely present in bloom_filter as bool.

fn lookup_percpu( &self, key: &[u8], flags: MapFlags, ) -> Result<Option<Vec<Vec<u8>>>>

Returns one value per cpu as Vec of Vec of u8 for per per-cpu maps.

fn delete(&self, key: &[u8]) -> Result<()>

Deletes an element from the map.

fn delete_batch( &self, keys: &[u8], count: u32, elem_flags: MapFlags, flags: MapFlags, ) -> Result<()>

Deletes many elements in batch mode from the map.

fn lookup_and_delete(&self, key: &[u8]) -> Result<Option<Vec<u8>>>

Same as Self::lookup() except this also deletes the key from the map.

fn update(&self, key: &[u8], value: &[u8], flags: MapFlags) -> Result<()>

Update an element.

fn update_batch( &self, keys: &[u8], values: &[u8], count: u32, elem_flags: MapFlags, flags: MapFlags, ) -> Result<()>

Updates many elements in batch mode in the map

fn update_percpu( &self, key: &[u8], values: &[Vec<u8>], flags: MapFlags, ) -> Result<()>

Update an element in an per-cpu map with one value per cpu.

impl TryFrom<&MapHandle> for MapHandle

type Error = Error

The type returned in the event of a conversion error.

fn try_from(other: &MapHandle) -> Result<Self>

Performs the conversion.

impl<T> TryFrom<&MapImpl<'_, T>> for MapHandle

where T: Debug,

type Error = Error

The type returned in the event of a conversion error.

fn try_from(other: &MapImpl<'_, T>) -> Result<Self>

Performs the conversion.