bpf: add PerCpuArray

bpf/aya-bpf/src/maps/mod.rs

@@ -1,5 +1,6 @@
 pub mod array;
 pub mod hash_map;
+pub mod per_cpu_array;
 pub mod perf_map;
 pub mod queue;
 pub mod sock_hash;
@@ -8,6 +9,7 @@ pub mod stack_trace;
 
 pub use array::Array;
 pub use hash_map::HashMap;
+pub use per_cpu_array::PerCpuArray;
 pub use perf_map::PerfMap;
 pub use queue::Queue;
 pub use sock_hash::SockHash;

bpf/aya-bpf/src/maps/per_cpu_array.rs

@@ -0,0 +1,59 @@
+use core::{marker::PhantomData, mem};
+
+use aya_bpf_cty::c_void;
+
+use crate::{
+    bindings::{bpf_map_def, bpf_map_type::BPF_MAP_TYPE_PERCPU_ARRAY},
+    helpers::bpf_map_lookup_elem,
+};
+
+#[repr(transparent)]
+pub struct PerCpuArray<T> {
+    def: bpf_map_def,
+    _t: PhantomData<T>,
+}
+
+impl<T> PerCpuArray<T> {
+    pub const fn with_max_entries(max_entries: u32, flags: u32) -> PerCpuArray<T> {
+        PerCpuArray {
+            def: bpf_map_def {
+                type_: BPF_MAP_TYPE_PERCPU_ARRAY,
+                key_size: mem::size_of::<u32>() as u32,
+                value_size: mem::size_of::<T>() as u32,
+                max_entries,
+                map_flags: flags,
+                id: 0,
+                pinning: 0,
+            },
+            _t: PhantomData,
+        }
+    }
+
+    #[inline(always)]
+    pub unsafe fn get(&mut self, index: u32) -> Option<&T> {
+        let value = bpf_map_lookup_elem(
+            &mut self.def as *mut _ as *mut _,
+            &index as *const _ as *const c_void,
+        );
+        if value.is_null() {
+            None
+        } else {
+            // FIXME: alignment
+            Some(&*(value as *const T))
+        }
+    }
+
+    #[inline(always)]
+    pub unsafe fn get_mut(&mut self, index: u32) -> Option<&mut T> {
+        let value = bpf_map_lookup_elem(
+            &mut self.def as *mut _ as *mut _,
+            &index as *const _ as *const c_void,
+        );
+        if value.is_null() {
+            None
+        } else {
+            // FIXME: alignment
+            Some(&mut *(value as *mut T))
+        }
+    }
+}