aya/ebpf/aya-ebpf/src/btf_maps/hash_map.rs

215 lines
7.9 KiB
Rust

use core::{cell::UnsafeCell, ptr::NonNull};
use aya_ebpf_bindings::bindings::bpf_map_type::BPF_MAP_TYPE_PERCPU_HASH;
use crate::{
bindings::bpf_map_type::{BPF_MAP_TYPE_HASH, BPF_MAP_TYPE_LRU_HASH},
btf_map_def,
cty::{c_long, c_void},
helpers::{bpf_map_delete_elem, bpf_map_lookup_elem, bpf_map_update_elem},
};
btf_map_def!(HashMapDef, BPF_MAP_TYPE_HASH);
#[repr(transparent)]
pub struct HashMap<K, V, const M: usize, const F: usize = 0>(UnsafeCell<HashMapDef<K, V, M, F>>);
unsafe impl<K: Sync, V: Sync, const M: usize, const F: usize> Sync for HashMap<K, V, M, F> {}
impl<K, V, const M: usize, const F: usize> HashMap<K, V, M, F> {
// Implementing `Default` makes no sense in this case. Maps are always
// global variables, so they need to be instantiated with a `const` method.
// `Default::default` method is not `const`.
#[allow(clippy::new_without_default)]
pub const fn new() -> HashMap<K, V, M, F> {
HashMap(UnsafeCell::new(HashMapDef::new()))
}
/// Retrieve the value associate with `key` from the map.
/// This function is unsafe. Unless the map flag `BPF_F_NO_PREALLOC` is used, the kernel does not
/// make guarantee on the atomicity of `insert` or `remove`, and any element removed from the
/// map might get aliased by another element in the map, causing garbage to be read, or
/// corruption in case of writes.
#[inline]
pub unsafe fn get(&self, key: &K) -> Option<&V> {
get(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, but this returns a raw pointer and it's up to the caller
/// to decide whether it's safe to dereference the pointer or not.
#[inline]
pub fn get_ptr(&self, key: &K) -> Option<*const V> {
get_ptr(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, and additionally cares should be taken to avoid
/// concurrent writes, but it's up to the caller to decide whether it's safe to dereference the
/// pointer or not.
#[inline]
pub fn get_ptr_mut(&self, key: &K) -> Option<*mut V> {
get_ptr_mut(self.0.get() as _, key)
}
#[inline]
pub fn insert(&self, key: &K, value: &V, flags: u64) -> Result<(), c_long> {
insert(self.0.get() as _, key, value, flags)
}
#[inline]
pub fn remove(&self, key: &K) -> Result<(), c_long> {
remove(self.0.get() as _, key)
}
}
btf_map_def!(LruHashMapDef, BPF_MAP_TYPE_LRU_HASH);
#[repr(transparent)]
pub struct LruHashMap<K, V, const M: usize, const F: usize = 0>(
UnsafeCell<LruHashMapDef<K, V, M, F>>,
);
unsafe impl<K: Sync, V: Sync, const M: usize, const F: usize> Sync for LruHashMap<K, V, M, F> {}
impl<K, V, const M: usize, const F: usize> LruHashMap<K, V, M, F> {
// Implementing `Default` makes no sense in this case. Maps are always
// global variables, so they need to be instantiated with a `const` method.
// The `Default::default` method is not `const`.
#[allow(clippy::new_without_default)]
pub const fn new() -> LruHashMap<K, V, M, F> {
LruHashMap(UnsafeCell::new(LruHashMapDef::new()))
}
/// Retrieve the value associate with `key` from the map.
/// This function is unsafe. Unless the map flag `BPF_F_NO_PREALLOC` is used, the kernel does not
/// make guarantee on the atomicity of `insert` or `remove`, and any element removed from the
/// map might get aliased by another element in the map, causing garbage to be read, or
/// corruption in case of writes.
#[inline]
pub unsafe fn get(&self, key: &K) -> Option<&V> {
get(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, but this returns a raw pointer and it's up to the caller
/// to decide whether it's safe to dereference the pointer or not.
#[inline]
pub fn get_ptr(&self, key: &K) -> Option<*const V> {
get_ptr(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, and additionally cares should be taken to avoid
/// concurrent writes, but it's up to the caller to decide whether it's safe to dereference the
/// pointer or not.
#[inline]
pub fn get_ptr_mut(&self, key: &K) -> Option<*mut V> {
get_ptr_mut(self.0.get() as _, key)
}
#[inline]
pub fn insert(&self, key: &K, value: &V, flags: u64) -> Result<(), c_long> {
insert(self.0.get() as _, key, value, flags)
}
#[inline]
pub fn remove(&self, key: &K) -> Result<(), c_long> {
remove(self.0.get() as _, key)
}
}
btf_map_def!(PerCpuHashMapDef, BPF_MAP_TYPE_PERCPU_HASH);
#[repr(transparent)]
pub struct PerCpuHashMap<K, V, const M: usize, const F: usize = 0>(
UnsafeCell<PerCpuHashMapDef<K, V, M, F>>,
);
unsafe impl<K, V, const M: usize, const F: usize> Sync for PerCpuHashMap<K, V, M, F> {}
impl<K, V, const M: usize, const F: usize> PerCpuHashMap<K, V, M, F> {
// Implementing `Default` makes no sense in this case. Maps are always
// global variables, so they need to be instantiated with a `const` method.
// The `Default::default` method is not `const`.
#[allow(clippy::new_without_default)]
pub const fn new() -> PerCpuHashMap<K, V, M, F> {
PerCpuHashMap(UnsafeCell::new(PerCpuHashMapDef::new()))
}
/// Retrieve the value associate with `key` from the map.
/// This function is unsafe. Unless the map flag `BPF_F_NO_PREALLOC` is used, the kernel does not
/// make guarantee on the atomicity of `insert` or `remove`, and any element removed from the
/// map might get aliased by another element in the map, causing garbage to be read, or
/// corruption in case of writes.
#[inline]
pub unsafe fn get(&self, key: &K) -> Option<&V> {
get(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, but this returns a raw pointer and it's up to the caller
/// to decide whether it's safe to dereference the pointer or not.
#[inline]
pub fn get_ptr(&self, key: &K) -> Option<*const V> {
get_ptr(self.0.get() as _, key)
}
/// Retrieve the value associate with `key` from the map.
/// The same caveat as `get` applies, and additionally cares should be taken to avoid
/// concurrent writes, but it's up to the caller to decide whether it's safe to dereference the
/// pointer or not.
#[inline]
pub fn get_ptr_mut(&self, key: &K) -> Option<*mut V> {
get_ptr_mut(self.0.get() as _, key)
}
#[inline]
pub fn insert(&self, key: &K, value: &V, flags: u64) -> Result<(), c_long> {
insert(self.0.get() as _, key, value, flags)
}
#[inline]
pub fn remove(&self, key: &K) -> Result<(), c_long> {
remove(self.0.get() as _, key)
}
}
#[inline]
fn get_ptr_mut<K, V>(def: *mut c_void, key: &K) -> Option<*mut V> {
unsafe {
let value = bpf_map_lookup_elem(def as *mut _, key as *const _ as *const c_void);
// FIXME: alignment
NonNull::new(value as *mut V).map(|p| p.as_ptr())
}
}
#[inline]
fn get_ptr<K, V>(def: *mut c_void, key: &K) -> Option<*const V> {
get_ptr_mut(def, key).map(|p| p as *const V)
}
#[inline]
unsafe fn get<'a, K, V>(def: *mut c_void, key: &K) -> Option<&'a V> {
get_ptr(def, key).map(|p| &*p)
}
#[inline]
fn insert<K, V>(def: *mut c_void, key: &K, value: &V, flags: u64) -> Result<(), c_long> {
let ret = unsafe {
bpf_map_update_elem(
def as *mut _,
key as *const _ as *const _,
value as *const _ as *const _,
flags,
)
};
(ret == 0).then_some(()).ok_or(ret)
}
#[inline]
fn remove<K>(def: *mut c_void, key: &K) -> Result<(), c_long> {
let ret = unsafe { bpf_map_delete_elem(def as *mut _, key as *const _ as *const c_void) };
(ret == 0).then_some(()).ok_or(ret)
}