aya: Implement XDP Map Types

This commit adds implementations for:
- xskmap
- devmap
- devmap_hash
- cpumap

Which can all be used to redirect XDP packets to various different
locations

Signed-off-by: Dave Tucker <[email protected]>

aya/src/maps/mod.rs

@@ -56,6 +56,7 @@ pub mod queue;
 pub mod sock;
 pub mod stack;
 pub mod stack_trace;
+pub mod xdp;
 
 pub use array::{Array, PerCpuArray, ProgramArray};
 pub use hash_map::{HashMap, PerCpuHashMap};
@@ -65,6 +66,7 @@ pub use queue::Queue;
 pub use sock::{SockHash, SockMap};
 pub use stack::Stack;
 pub use stack_trace::StackTraceMap;
+pub use xdp::XskMap;
 
 #[derive(Error, Debug)]
 /// Errors occuring from working with Maps

aya/src/maps/xdp/cpu_map.rs

@@ -0,0 +1,120 @@
+//! An array of available CPUs.
+
+use std::{
+    convert::TryFrom,
+    mem,
+    ops::{Deref, DerefMut},
+};
+
+use crate::{
+    generated::bpf_map_type::BPF_MAP_TYPE_CPUMAP,
+    maps::{Map, MapError, MapRef, MapRefMut},
+    sys::bpf_map_update_elem,
+};
+
+/// An array of available CPUs.
+///
+/// XDP programs can use this map to redirect packets to a target
+/// CPU for processing.
+///
+/// # Minimum kernel version
+///
+/// The minimum kernel version required to use this feature is 4.2.
+///
+/// # Examples
+/// ```no_run
+/// # let bpf = aya::Bpf::load(&[])?;
+/// use aya::maps::CpuMap;
+/// use std::convert::{TryFrom, TryInto};
+///
+/// let mut cpumap = CpuMap::try_from(bpf.map_mut("CPUS")?)?;
+/// let flags = 0;
+/// let queue_size = 2048;
+/// for i in 0u32..8u32 {
+///     cpumap.set(i, queue_size, flags);
+/// }
+///
+/// # Ok::<(), aya::BpfError>(())
+/// ```
+#[doc(alias = "BPF_MAP_TYPE_CPUMAP")]
+pub struct CpuMap<T: Deref<Target = Map>> {
+    inner: T,
+}
+
+impl<T: Deref<Target = Map>> CpuMap<T> {
+    fn new(map: T) -> Result<CpuMap<T>, MapError> {
+        let map_type = map.obj.def.map_type;
+        if map_type != BPF_MAP_TYPE_CPUMAP as u32 {
+            return Err(MapError::InvalidMapType {
+                map_type: map_type as u32,
+            });
+        }
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.key_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidKeySize { size, expected });
+        }
+
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.value_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidValueSize { size, expected });
+        }
+        let _fd = map.fd_or_err()?;
+
+        Ok(CpuMap { inner: map })
+    }
+
+    /// Returns the number of elements in the array.
+    ///
+    /// This corresponds to the value of `bpf_map_def::max_entries` on the eBPF side.
+    pub fn len(&self) -> u32 {
+        self.inner.obj.def.max_entries
+    }
+
+    fn check_bounds(&self, index: u32) -> Result<(), MapError> {
+        let max_entries = self.inner.obj.def.max_entries;
+        if index >= self.inner.obj.def.max_entries {
+            Err(MapError::OutOfBounds { index, max_entries })
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl<T: Deref<Target = Map> + DerefMut<Target = Map>> CpuMap<T> {
+    /// Sets the value of the element at the given index.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
+    /// if `bpf_map_update_elem` fails.
+    pub fn set(&mut self, index: u32, value: u32, flags: u64) -> Result<(), MapError> {
+        let fd = self.inner.fd_or_err()?;
+        self.check_bounds(index)?;
+        bpf_map_update_elem(fd, &index, &value, flags).map_err(|(code, io_error)| {
+            MapError::SyscallError {
+                call: "bpf_map_update_elem".to_owned(),
+                code,
+                io_error,
+            }
+        })?;
+        Ok(())
+    }
+}
+
+impl TryFrom<MapRef> for CpuMap<MapRef> {
+    type Error = MapError;
+
+    fn try_from(a: MapRef) -> Result<CpuMap<MapRef>, MapError> {
+        CpuMap::new(a)
+    }
+}
+
+impl TryFrom<MapRefMut> for CpuMap<MapRefMut> {
+    type Error = MapError;
+
+    fn try_from(a: MapRefMut) -> Result<CpuMap<MapRefMut>, MapError> {
+        CpuMap::new(a)
+    }
+}

aya/src/maps/xdp/dev_map.rs

@@ -0,0 +1,118 @@
+//! An array of network devices.
+
+use std::{
+    convert::TryFrom,
+    mem,
+    ops::{Deref, DerefMut},
+};
+
+use crate::{
+    generated::bpf_map_type::BPF_MAP_TYPE_DEVMAP,
+    maps::{Map, MapError, MapRef, MapRefMut},
+    sys::bpf_map_update_elem,
+};
+
+/// An array 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 4.2.
+///
+/// # Examples
+/// ```no_run
+/// # let bpf = aya::Bpf::load(&[])?;
+/// use aya::maps::DevMap;
+/// use std::convert::{TryFrom, TryInto};
+///
+/// let mut devmap = DevMap::try_from(bpf.map_mut("IFACES")?)?;
+/// let flags = 0;
+/// let ifindex = 32u32;
+/// devmap.set(ifindex, ifindex, flags);
+///
+/// # Ok::<(), aya::BpfError>(())
+/// ```
+#[doc(alias = "BPF_MAP_TYPE_DEVMAP")]
+pub struct DevMap<T: Deref<Target = Map>> {
+    inner: T,
+}
+
+impl<T: Deref<Target = Map>> DevMap<T> {
+    fn new(map: T) -> Result<DevMap<T>, MapError> {
+        let map_type = map.obj.def.map_type;
+        if map_type != BPF_MAP_TYPE_DEVMAP as u32 {
+            return Err(MapError::InvalidMapType {
+                map_type: map_type as u32,
+            });
+        }
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.key_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidKeySize { size, expected });
+        }
+
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.value_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidValueSize { size, expected });
+        }
+        let _fd = map.fd_or_err()?;
+
+        Ok(DevMap { inner: map })
+    }
+
+    /// Returns the number of elements in the array.
+    ///
+    /// This corresponds to the value of `bpf_map_def::max_entries` on the eBPF side.
+    pub fn len(&self) -> u32 {
+        self.inner.obj.def.max_entries
+    }
+
+    fn check_bounds(&self, index: u32) -> Result<(), MapError> {
+        let max_entries = self.inner.obj.def.max_entries;
+        if index >= self.inner.obj.def.max_entries {
+            Err(MapError::OutOfBounds { index, max_entries })
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl<T: Deref<Target = Map> + DerefMut<Target = Map>> DevMap<T> {
+    /// Sets the value of the element at the given index.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
+    /// if `bpf_map_update_elem` fails.
+    pub fn set(&mut self, index: u32, value: u32, flags: u64) -> Result<(), MapError> {
+        let fd = self.inner.fd_or_err()?;
+        self.check_bounds(index)?;
+        bpf_map_update_elem(fd, &index, &value, flags).map_err(|(code, io_error)| {
+            MapError::SyscallError {
+                call: "bpf_map_update_elem".to_owned(),
+                code,
+                io_error,
+            }
+        })?;
+        Ok(())
+    }
+}
+
+impl TryFrom<MapRef> for DevMap<MapRef> {
+    type Error = MapError;
+
+    fn try_from(a: MapRef) -> Result<DevMap<MapRef>, MapError> {
+        DevMap::new(a)
+    }
+}
+
+impl TryFrom<MapRefMut> for DevMap<MapRefMut> {
+    type Error = MapError;
+
+    fn try_from(a: MapRefMut) -> Result<DevMap<MapRefMut>, MapError> {
+        DevMap::new(a)
+    }
+}

aya/src/maps/xdp/dev_map_hash.rs

@@ -0,0 +1,118 @@
+//! An array of network devices.
+
+use std::{
+    convert::TryFrom,
+    mem,
+    ops::{Deref, DerefMut},
+};
+
+use crate::{
+    generated::bpf_map_type::BPF_MAP_TYPE_DEVMAP_HASH,
+    maps::{Map, MapError, MapRef, MapRefMut},
+    sys::bpf_map_update_elem,
+};
+
+/// An array 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 4.2.
+///
+/// # Examples
+/// ```no_run
+/// # let bpf = aya::Bpf::load(&[])?;
+/// use aya::maps::DevMapHash;
+/// use std::convert::{TryFrom, TryInto};
+///
+/// let mut devmap = DevMapHash::try_from(bpf.map_mut("IFACES")?)?;
+/// let flags = 0;
+/// let ifindex = 32u32;
+/// devmap.set(ifindex, ifindex, flags);
+///
+/// # Ok::<(), aya::BpfError>(())
+/// ```
+#[doc(alias = "BPF_MAP_TYPE_DEVMAP_HASH")]
+pub struct DevMapHash<T: Deref<Target = Map>> {
+    inner: T,
+}
+
+impl<T: Deref<Target = Map>> DevMapHash<T> {
+    fn new(map: T) -> Result<DevMapHash<T>, MapError> {
+        let map_type = map.obj.def.map_type;
+        if map_type != BPF_MAP_TYPE_DEVMAP_HASH as u32 {
+            return Err(MapError::InvalidMapType {
+                map_type: map_type as u32,
+            });
+        }
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.key_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidKeySize { size, expected });
+        }
+
+        let expected = mem::size_of::<u32>();
+        let size = map.obj.def.value_size as usize;
+        if size != expected {
+            return Err(MapError::InvalidValueSize { size, expected });
+        }
+        let _fd = map.fd_or_err()?;
+
+        Ok(DevMapHash { inner: map })
+    }
+
+    /// Returns the number of elements in the array.
+    ///
+    /// This corresponds to the value of `bpf_map_def::max_entries` on the eBPF side.
+    pub fn len(&self) -> u32 {
+        self.inner.obj.def.max_entries
+    }
+
+    fn check_bounds(&self, index: u32) -> Result<(), MapError> {
+        let max_entries = self.inner.obj.def.max_entries;
+        if index >= self.inner.obj.def.max_entries {
+            Err(MapError::OutOfBounds { index, max_entries })
+        } else {
+            Ok(())
+        }
+    }
+}
+
+impl<T: Deref<Target = Map> + DerefMut<Target = Map>> DevMapHash<T> {
+    /// Sets the value of the element at the given index.
+    ///
+    /// # Errors
+    ///
+    /// Returns [`MapError::OutOfBounds`] if `index` is out of bounds, [`MapError::SyscallError`]
+    /// if `bpf_map_update_elem` fails.
+    pub fn set(&mut self, index: u32, value: u32, flags: u64) -> Result<(), MapError> {
+        let fd = self.inner.fd_or_err()?;
+        self.check_bounds(index)?;
+        bpf_map_update_elem(fd, &index, &value, flags).map_err(|(code, io_error)| {
+            MapError::SyscallError {
+                call: "bpf_map_update_elem".to_owned(),
+                code,
+                io_error,
+            }
+        })?;
+        Ok(())
+    }
+}
+
+impl TryFrom<MapRef> for DevMapHash<MapRef> {
+    type Error = MapError;
+
+    fn try_from(a: MapRef) -> Result<DevMapHash<MapRef>, MapError> {
+        DevMapHash::new(a)
+    }
+}
+
+impl TryFrom<MapRefMut> for DevMapHash<MapRefMut> {
+    type Error = MapError;
+
+    fn try_from(a: MapRefMut) -> Result<DevMapHash<MapRefMut>, MapError> {
+        DevMapHash::new(a)
+    }
+}

aya/src/maps/xdp/mod.rs

@@ -0,0 +1,10 @@
+//! XDP maps.
+mod cpu_map;
+mod dev_map;
+mod dev_map_hash;
+mod xsk_map;
+
+pub use cpu_map::CpuMap;
+pub use dev_map::DevMap;
+pub use dev_map_hash::DevMapHash;
+pub use xsk_map::XskMap;