Struct DevMapHash 

pub struct DevMapHash<T> { /* private fields */ }

An hashmap of network devices.

XDP programs can use this map to redirect to other network devices.

Minimum kernel version

The minimum kernel version required to use this feature is 5.4.

Examples

use aya::maps::xdp::DevMapHash;

let mut devmap = DevMapHash::try_from(bpf.map_mut("IFACES").unwrap())?;
// Lookups with key 2 will redirect packets to interface with index 3 (e.g. eth1)
devmap.insert(2, 3, None, 0);

See also

Kernel documentation: https://docs.kernel.org/next/bpf/map_devmap.html

Implementations

impl<T: Borrow<MapData>> DevMapHash<T>

pub fn get(&self, key: u32, flags: u64) -> Result<DevMapValue, MapError>

Returns the target interface index and optional program for a given key.

Errors

Returns MapError::SyscallError if bpf_map_lookup_elem fails.

pub fn iter(&self) -> MapIter<'_, u32, DevMapValue, Self>

An iterator over the elements of the devmap in arbitrary order.

pub fn keys(&self) -> MapKeys<'_, u32>

An iterator visiting all keys in arbitrary order.

impl<T: BorrowMut<MapData>> DevMapHash<T>

pub fn insert( &mut self, key: u32, target_if_index: u32, program: Option<&ProgramFd>, flags: u64, ) -> Result<(), XdpMapError>

Inserts an ifindex and optionally a chained program in the map.

When redirecting using key, packets will be transmitted by the interface with ifindex.

Starting from Linux kernel 5.8, another XDP program can be passed in that will be run before actual transmission. It can be used to modify the packet before transmission with NIC specific data (MAC address update, checksum computations, etc) or other purposes.

The chained program must be loaded with the BPF_XDP_DEVMAP attach type. When using aya-ebpf, that means XDP programs that specify the map = "devmap" argument. See the kernel-space aya_ebpf::xdp for more information.

Errors

Returns MapError::SyscallError if bpf_map_update_elem fails, MapError::ProgIdNotSupported if the kernel does not support chained programs and one is provided.

pub fn remove(&mut self, key: u32) -> Result<(), MapError>

Removes a value from the map.

Errors

Returns MapError::SyscallError if bpf_map_delete_elem fails.

impl<T: Borrow<MapData>> DevMapHash<T>

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

Pins the map to a BPF filesystem.

When a map is pinned it will remain loaded until the corresponding file is deleted. All parent directories in the given path must already exist.

Trait Implementations

impl<'a, T: Borrow<MapData>> IntoIterator for &'a DevMapHash<T>

type Item = Result<(u32, DevMapValue), MapError>

The type of the elements being iterated over.

type IntoIter = MapIter<'a, u32, DevMapValue, DevMapHash<T>>

Which kind of iterator are we turning this into?

fn into_iter(self) -> Self::IntoIter

Creates an iterator from a value.

impl<'a> TryFrom<&'a Map> for DevMapHash<&'a MapData>

type Error = MapError

The type returned in the event of a conversion error.

fn try_from(map: &'a Map) -> Result<Self, Self::Error>

Performs the conversion.

impl<'a> TryFrom<&'a mut Map> for DevMapHash<&'a mut MapData>

type Error = MapError

The type returned in the event of a conversion error.

fn try_from(map: &'a mut Map) -> Result<Self, Self::Error>

Performs the conversion.

impl TryFrom<Map> for DevMapHash<MapData>

type Error = MapError

The type returned in the event of a conversion error.

fn try_from(map: Map) -> Result<Self, Self::Error>

Performs the conversion.