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sk_lookup.rs
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sk_lookup.rs
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use std::os::unix::prelude::{AsRawFd, RawFd};
use crate::{
generated::{bpf_attach_type::BPF_SK_LOOKUP, bpf_prog_type::BPF_PROG_TYPE_SK_LOOKUP},
programs::{define_link_wrapper, load_program, FdLinkId, OwnedLink, ProgramData, ProgramError},
sys::bpf_link_create,
};
use super::links::FdLink;
/// A program used to redirect incoming packets to a local socket.
///
/// [`SkLookup`] programs are attached to network namespaces to provide programmable
/// socket lookup for TCP/UDP when a packet is to be delievered locally.
///
/// You may attach multiple programs to the same namespace and they are executed
/// in the order they were attached.
///
/// # Minimum kernel version
///
/// The minimum kernel version required to use this feature is 5.9.
///
/// # Examples
///
/// ```no_run
/// # #[derive(Debug, thiserror::Error)]
/// # enum Error {
/// # #[error(transparent)]
/// # IO(#[from] std::io::Error),
/// # #[error(transparent)]
/// # Map(#[from] aya::maps::MapError),
/// # #[error(transparent)]
/// # Program(#[from] aya::programs::ProgramError),
/// # #[error(transparent)]
/// # Bpf(#[from] aya::BpfError)
/// # }
/// # let mut bpf = aya::Bpf::load(&[])?;
/// use std::fs::File;
/// use std::convert::TryInto;
/// use aya::programs::SkLookup;
///
/// let file = File::open("/var/run/netns/test")?;
/// let program: &mut SkLookup = bpf.program_mut("sk_lookup").unwrap().try_into()?;
/// program.load()?;
/// program.attach(file)?;
/// # Ok::<(), Error>(())
/// ```
#[derive(Debug)]
#[doc(alias = "BPF_PROG_TYPE_SK_LOOKUP")]
pub struct SkLookup {
pub(crate) data: ProgramData<SkLookupLink>,
}
impl SkLookup {
/// Loads the program inside the kernel.
pub fn load(&mut self) -> Result<(), ProgramError> {
self.data.expected_attach_type = Some(BPF_SK_LOOKUP);
load_program(BPF_PROG_TYPE_SK_LOOKUP, &mut self.data)
}
/// Attaches the program to the given network namespace.
///
/// The returned value can be used to detach, see [SkLookup::detach].
pub fn attach<T: AsRawFd>(&mut self, netns: T) -> Result<SkLookupLinkId, ProgramError> {
let prog_fd = self.data.fd_or_err()?;
let netns_fd = netns.as_raw_fd();
let link_fd = bpf_link_create(prog_fd, netns_fd, BPF_SK_LOOKUP, None, 0).map_err(
|(_, io_error)| ProgramError::SyscallError {
call: "bpf_link_create".to_owned(),
io_error,
},
)? as RawFd;
self.data.links.insert(SkLookupLink(FdLink::new(link_fd)))
}
/// Takes ownership of the link referenced by the provided link_id.
///
/// The link will be detached on `Drop` and the caller is now responsible
/// for managing its lifetime.
pub fn take_link(
&mut self,
link_id: SkLookupLinkId,
) -> Result<OwnedLink<SkLookupLink>, ProgramError> {
Ok(OwnedLink::new(self.data.take_link(link_id)?))
}
/// Detaches the program.
///
/// See [SkLookup::attach].
pub fn detach(&mut self, link_id: SkLookupLinkId) -> Result<(), ProgramError> {
self.data.links.remove(link_id)
}
}
define_link_wrapper!(
/// The link used by [SkLookup] programs.
SkLookupLink,
/// The type returned by [SkLookup::attach]. Can be passed to [SkLookup::detach].
SkLookupLinkId,
FdLink,
FdLinkId
);