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use bitflags;
use libc::if_nametoindex;
use std::{ffi::CString, io, os::unix::io::RawFd};
use thiserror::Error;
use crate::{
generated::{
bpf_attach_type::{self, BPF_XDP},
bpf_prog_type::BPF_PROG_TYPE_XDP,
XDP_FLAGS_DRV_MODE, XDP_FLAGS_HW_MODE, XDP_FLAGS_REPLACE, XDP_FLAGS_SKB_MODE,
XDP_FLAGS_UPDATE_IF_NOEXIST,
},
programs::{load_program, FdLink, Link, LinkRef, ProgramData, ProgramError},
sys::{bpf_link_create, kernel_version, netlink_set_xdp_fd},
};
#[derive(Debug, Error)]
pub enum XdpError {
#[error("netlink error while attaching XDP program")]
NetlinkError {
#[source]
io_error: io::Error,
},
}
bitflags! {
#[derive(Default)]
pub struct XdpFlags: u32 {
const SKB_MODE = XDP_FLAGS_SKB_MODE;
const DRV_MODE = XDP_FLAGS_DRV_MODE;
const HW_MODE = XDP_FLAGS_HW_MODE;
const REPLACE = XDP_FLAGS_REPLACE;
const UPDATE_IF_NOEXIST = XDP_FLAGS_UPDATE_IF_NOEXIST;
}
}
#[derive(Debug)]
#[doc(alias = "BPF_PROG_TYPE_XDP")]
pub struct Xdp {
pub(crate) data: ProgramData,
}
impl Xdp {
pub fn load(&mut self) -> Result<(), ProgramError> {
self.data.expected_attach_type = Some(bpf_attach_type::BPF_XDP);
load_program(BPF_PROG_TYPE_XDP, &mut self.data)
}
pub fn attach(&mut self, interface: &str, flags: XdpFlags) -> Result<LinkRef, ProgramError> {
let prog_fd = self.data.fd_or_err()?;
let c_interface = CString::new(interface).unwrap();
let if_index = unsafe { if_nametoindex(c_interface.as_ptr()) } as RawFd;
if if_index == 0 {
return Err(ProgramError::UnknownInterface {
name: interface.to_string(),
});
}
let k_ver = kernel_version().unwrap();
if k_ver >= (5, 9, 0) {
let link_fd = bpf_link_create(prog_fd, if_index, BPF_XDP, None, flags.bits).map_err(
|(_, io_error)| ProgramError::SyscallError {
call: "bpf_link_create".to_owned(),
io_error,
},
)? as RawFd;
Ok(self
.data
.link(XdpLink::FdLink(FdLink { fd: Some(link_fd) })))
} else {
unsafe { netlink_set_xdp_fd(if_index, prog_fd, None, flags.bits) }
.map_err(|io_error| XdpError::NetlinkError { io_error })?;
Ok(self.data.link(XdpLink::NlLink(NlLink {
if_index,
prog_fd: Some(prog_fd),
flags,
})))
}
}
}
#[derive(Debug)]
struct NlLink {
if_index: i32,
prog_fd: Option<RawFd>,
flags: XdpFlags,
}
impl Link for NlLink {
fn detach(&mut self) -> Result<(), ProgramError> {
if let Some(fd) = self.prog_fd.take() {
let k_ver = kernel_version().unwrap();
let flags = if k_ver >= (5, 7, 0) {
self.flags.bits | XDP_FLAGS_REPLACE
} else {
self.flags.bits
};
let _ = unsafe { netlink_set_xdp_fd(self.if_index, -1, Some(fd), flags) };
Ok(())
} else {
Err(ProgramError::AlreadyDetached)
}
}
}
impl Drop for NlLink {
fn drop(&mut self) {
let _ = self.detach();
}
}
#[derive(Debug)]
enum XdpLink {
FdLink(FdLink),
NlLink(NlLink),
}
impl Link for XdpLink {
fn detach(&mut self) -> Result<(), ProgramError> {
match self {
XdpLink::FdLink(link) => link.detach(),
XdpLink::NlLink(link) => link.detach(),
}
}
}