mirror of https://github.com/aya-rs/aya
aya: Implement Maps/Arrays of Maps
Signed-off-by: Dave Tucker <dave@dtucker.co.uk>pull/70/head
parent
4152e8b1a4
commit
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//! An array of eBPF maps.
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use std::{
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convert::TryFrom,
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mem,
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ops::{Deref, DerefMut},
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os::unix::{io::IntoRawFd, prelude::RawFd},
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};
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use crate::{
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generated::bpf_map_type::BPF_MAP_TYPE_ARRAY_OF_MAPS,
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maps::{of_maps::MapOfMaps, Map, MapError, MapKeys, MapRef, MapRefMut},
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sys::{bpf_map_delete_elem, bpf_map_get_fd_by_id, bpf_map_lookup_elem, bpf_map_update_elem},
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};
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/// An array of eBPF Maps
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///
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/// A `Array` is used to store references to other maps.
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///
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/// # Minimum kernel version
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///
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/// The minimum kernel version required to use this feature is 4.14.
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#[doc(alias = "BPF_MAP_TYPE_ARRAY_OF_MAPS")]
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pub struct Array<T: Deref<Target = Map>> {
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pub(crate) inner: T,
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}
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impl<T: Deref<Target = Map>> Array<T> {
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fn new(map: T) -> Result<Array<T>, MapError> {
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let map_type = map.obj.def.map_type;
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if map_type != BPF_MAP_TYPE_ARRAY_OF_MAPS as u32 {
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return Err(MapError::InvalidMapType {
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map_type: map_type as u32,
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});
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}
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let expected = mem::size_of::<u32>();
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let size = map.obj.def.key_size as usize;
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if size != expected {
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return Err(MapError::InvalidKeySize { size, expected });
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}
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let expected = mem::size_of::<u32>();
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let size = map.obj.def.value_size as usize;
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if size != expected {
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return Err(MapError::InvalidValueSize { size, expected });
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}
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let _fd = map.fd_or_err()?;
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Ok(Array { inner: map })
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}
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/// An iterator over the indices of the array that point to a map. The iterator item type
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/// is `Result<u32, MapError>`.
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pub unsafe fn indices(&self) -> MapKeys<'_, u32> {
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MapKeys::new(&self.inner)
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}
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fn check_bounds(&self, index: u32) -> Result<(), MapError> {
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let max_entries = self.inner.obj.def.max_entries;
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if index >= self.inner.obj.def.max_entries {
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Err(MapError::OutOfBounds { index, max_entries })
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} else {
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Ok(())
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}
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}
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/// Returns the fd of the map stored at the given index.
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///
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/// # Errors
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///
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/// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
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/// if `bpf_map_lookup_elem` fails.
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pub fn get(&self, index: &u32, flags: u64) -> Result<RawFd, MapError> {
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self.check_bounds(*index)?;
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let fd = self.inner.fd_or_err()?;
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let id = bpf_map_lookup_elem(fd, index, flags)
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.map_err(|(code, io_error)| MapError::SyscallError {
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call: "bpf_map_lookup_elem".to_owned(),
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code,
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io_error,
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})?
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.ok_or(MapError::KeyNotFound)?;
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let inner_fd = bpf_map_get_fd_by_id(id).map_err(|io_error| MapError::SyscallError {
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call: "bpf_map_get_fd_by_id".to_owned(),
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code: 0,
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io_error,
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})?;
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Ok(inner_fd as RawFd)
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}
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}
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impl<T: Deref<Target = Map> + DerefMut<Target = Map>> Array<T> {
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/// Stores a map fd into the map.
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pub fn set<I: IntoRawFd>(&mut self, index: u32, map: I, flags: u64) -> Result<(), MapError> {
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let fd = self.inner.fd_or_err()?;
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let map_fd = map.into_raw_fd();
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self.check_bounds(index)?;
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bpf_map_update_elem(fd, &index, &map_fd, flags).map_err(|(code, io_error)| {
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MapError::SyscallError {
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call: "bpf_map_update_elem".to_owned(),
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code,
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io_error,
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}
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})?;
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// safety: we're closing a RawFd which we have ownership of
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// this is required because inserting this in to the map causes
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// there to be a reference to the map in both kernel and userspace
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unsafe { libc::close(map_fd) };
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Ok(())
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}
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/// Removes the map stored at `index` from the map.
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pub fn delete(&mut self, index: &u32) -> Result<(), MapError> {
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let fd = self.inner.fd_or_err()?;
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self.check_bounds(*index)?;
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bpf_map_delete_elem(fd, index)
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.map(|_| ())
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.map_err(|(code, io_error)| MapError::SyscallError {
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call: "bpf_map_delete_elem".to_owned(),
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code,
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io_error,
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})
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}
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}
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impl<T: Deref<Target = Map> + DerefMut<Target = Map>> MapOfMaps for Array<T> {
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fn fd_or_err(&self) -> Result<RawFd, MapError> {
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self.inner.fd_or_err()
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}
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}
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impl TryFrom<MapRef> for Array<MapRef> {
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type Error = MapError;
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fn try_from(a: MapRef) -> Result<Array<MapRef>, MapError> {
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Array::new(a)
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}
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}
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impl TryFrom<MapRefMut> for Array<MapRefMut> {
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type Error = MapError;
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fn try_from(a: MapRefMut) -> Result<Array<MapRefMut>, MapError> {
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Array::new(a)
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}
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}
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@ -0,0 +1,129 @@
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use std::{
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convert::TryFrom,
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marker::PhantomData,
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ops::{Deref, DerefMut},
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os::unix::io::{IntoRawFd, RawFd},
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};
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use crate::{
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generated::bpf_map_type::BPF_MAP_TYPE_HASH_OF_MAPS,
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maps::{
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hash_map, of_maps::MapOfMaps, IterableMap, Map, MapError, MapIter, MapKeys, MapRef,
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MapRefMut,
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},
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sys::{bpf_map_get_fd_by_id, bpf_map_lookup_elem},
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Pod,
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};
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/// A hash map of eBPF Maps.
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///
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/// A `HashMap` is used to store references to eBPF Maps
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///
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/// # Minimum kernel version
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///
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/// The minimum kernel version required to use this feature is 4.18.
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#[doc(alias = "BPF_MAP_TYPE_HASH_OF_MAPS")]
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pub struct HashMap<T: Deref<Target = Map>, K> {
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inner: T,
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_k: PhantomData<K>,
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}
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impl<T: Deref<Target = Map>, K: Pod> HashMap<T, K> {
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pub(crate) fn new(map: T) -> Result<HashMap<T, K>, MapError> {
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let map_type = map.obj.def.map_type;
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// validate the map definition
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if map_type != BPF_MAP_TYPE_HASH_OF_MAPS as u32 {
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return Err(MapError::InvalidMapType {
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map_type: map_type as u32,
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});
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}
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hash_map::check_kv_size::<K, u32>(&map)?;
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let _ = map.fd_or_err()?;
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Ok(HashMap {
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inner: map,
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_k: PhantomData,
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})
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}
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/// Returns the fd of the map stored at the given key.
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pub unsafe fn get(&self, key: &K, flags: u64) -> Result<RawFd, MapError> {
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let fd = self.inner.deref().fd_or_err()?;
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let id = bpf_map_lookup_elem(fd, key, flags)
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.map_err(|(code, io_error)| MapError::SyscallError {
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call: "bpf_map_lookup_elem".to_owned(),
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code,
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io_error,
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})?
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.ok_or(MapError::KeyNotFound)?;
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let inner_fd = bpf_map_get_fd_by_id(id).map_err(|io_error| MapError::SyscallError {
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call: "bpf_map_get_fd_by_id".to_owned(),
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code: 0,
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io_error,
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})?;
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Ok(inner_fd as RawFd)
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}
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/// An iterator visiting all key-value pairs in arbitrary order. The
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/// iterator item type is `Result<(K, V), MapError>`.
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pub unsafe fn iter(&self) -> MapIter<'_, K, RawFd> {
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MapIter::new(self)
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}
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/// An iterator visiting all keys in arbitrary order. The iterator element
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/// type is `Result<K, MapError>`.
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pub unsafe fn keys(&self) -> MapKeys<'_, K> {
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MapKeys::new(&self.inner)
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}
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}
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impl<T: DerefMut<Target = Map>, K: Pod> HashMap<T, K> {
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/// Inserts a map under the given key.
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pub fn insert<I: IntoRawFd>(&mut self, key: K, value: I, flags: u64) -> Result<(), MapError> {
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let map_fd = value.into_raw_fd();
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hash_map::insert(&mut self.inner, key, map_fd, flags)?;
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// safety: we're closing a RawFd which we have ownership of
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// this is required because inserting this in to the map causes
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// there to be a reference to the map in both kernel and userspace
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unsafe { libc::close(map_fd) };
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Ok(())
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}
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/// Removes a map from the map.
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pub fn remove(&mut self, key: &K) -> Result<(), MapError> {
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hash_map::remove(&mut self.inner, key)
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}
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}
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impl<T: Deref<Target = Map>, K: Pod> IterableMap<K, RawFd> for HashMap<T, K> {
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fn map(&self) -> &Map {
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&self.inner
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}
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unsafe fn get(&self, key: &K) -> Result<RawFd, MapError> {
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HashMap::get(self, key, 0)
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}
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}
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impl<T: DerefMut<Target = Map>, K: Pod> MapOfMaps for HashMap<T, K> {
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fn fd_or_err(&self) -> Result<RawFd, MapError> {
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self.inner.fd_or_err()
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}
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}
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impl<K: Pod> TryFrom<MapRef> for HashMap<MapRef, K> {
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type Error = MapError;
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fn try_from(a: MapRef) -> Result<HashMap<MapRef, K>, MapError> {
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HashMap::new(a)
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}
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}
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impl<K: Pod> TryFrom<MapRefMut> for HashMap<MapRefMut, K> {
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type Error = MapError;
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fn try_from(a: MapRefMut) -> Result<HashMap<MapRefMut, K>, MapError> {
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HashMap::new(a)
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}
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}
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@ -0,0 +1,14 @@
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//! Maps of maps
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mod array;
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mod hash_map;
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use std::os::unix::io::RawFd;
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use crate::maps::MapError;
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pub use array::Array;
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pub use hash_map::HashMap;
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pub trait MapOfMaps {
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fn fd_or_err(&self) -> Result<RawFd, MapError>;
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}
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