Merge pull request #418 from anfredette/tc-handle

Support using handle in tc programs
pull/446/head
Alessandro Decina 2 years ago committed by GitHub
commit 7fef833e3a
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1
.gitignore vendored

@ -5,3 +5,4 @@ libbpf/
!.vscode/settings.json
site/
header.html
.idea/

@ -63,7 +63,7 @@ pub enum TcAttachType {
///
/// let prog: &mut SchedClassifier = bpf.program_mut("redirect_ingress").unwrap().try_into()?;
/// prog.load()?;
/// prog.attach("eth0", TcAttachType::Ingress, 0)?;
/// prog.attach("eth0", TcAttachType::Ingress)?;
///
/// # Ok::<(), Error>(())
/// ```
@ -99,17 +99,24 @@ impl TcAttachType {
}
}
/// Options for SchedClassifier attach
#[derive(Default)]
pub struct TcOptions {
/// Priority assigned to tc program with lower number = higher priority.
/// If set to default (0), the system chooses the next highest priority or 49152 if no filters exist yet
pub priority: u16,
/// Handle used to uniquely identify a program at a given priority level.
/// If set to default (0), the system chooses a handle.
pub handle: u32,
}
impl SchedClassifier {
/// Loads the program inside the kernel.
pub fn load(&mut self) -> Result<(), ProgramError> {
load_program(BPF_PROG_TYPE_SCHED_CLS, &mut self.data)
}
/// Attaches the program to the given `interface`.
///
/// Valid priority values range from 0 - 65535 with lower number = higher priority.
/// 0 means let the system choose the next highest priority, or 49152 if no filters exist yet.
/// All other values in the range are taken as an explicit priority setting (aka "preference").
/// Attaches the program to the given `interface` using the default options.
///
/// The returned value can be used to detach, see [SchedClassifier::detach].
///
@ -123,13 +130,38 @@ impl SchedClassifier {
&mut self,
interface: &str,
attach_type: TcAttachType,
priority: u16,
) -> Result<SchedClassifierLinkId, ProgramError> {
self.attach_with_options(interface, attach_type, TcOptions::default())
}
/// Attaches the program to the given `interface` with options defined in [`TcOptions`].
///
/// The returned value can be used to detach, see [SchedClassifier::detach].
///
/// # Errors
///
/// [`TcError::NetlinkError`] is returned if attaching fails. A common cause
/// of failure is not having added the `clsact` qdisc to the given
/// interface, see [`qdisc_add_clsact`]
///
pub fn attach_with_options(
&mut self,
interface: &str,
attach_type: TcAttachType,
options: TcOptions,
) -> Result<SchedClassifierLinkId, ProgramError> {
let prog_fd = self.data.fd_or_err()?;
let if_index = ifindex_from_ifname(interface)
.map_err(|io_error| TcError::NetlinkError { io_error })?;
let priority = unsafe {
netlink_qdisc_attach(if_index as i32, &attach_type, prog_fd, &self.name, priority)
let (priority, handle) = unsafe {
netlink_qdisc_attach(
if_index as i32,
&attach_type,
prog_fd,
&self.name,
options.priority,
options.handle,
)
}
.map_err(|io_error| TcError::NetlinkError { io_error })?;
@ -137,6 +169,7 @@ impl SchedClassifier {
if_index: if_index as i32,
attach_type,
priority,
handle,
}))
}
@ -160,25 +193,28 @@ impl SchedClassifier {
}
#[derive(Debug, Hash, Eq, PartialEq)]
pub(crate) struct TcLinkId(i32, TcAttachType, u16);
pub(crate) struct TcLinkId(i32, TcAttachType, u16, u32);
#[derive(Debug)]
struct TcLink {
if_index: i32,
attach_type: TcAttachType,
priority: u16,
handle: u32,
}
impl Link for TcLink {
type Id = TcLinkId;
fn id(&self) -> Self::Id {
TcLinkId(self.if_index, self.attach_type, self.priority)
TcLinkId(self.if_index, self.attach_type, self.priority, self.handle)
}
fn detach(self) -> Result<(), ProgramError> {
unsafe { netlink_qdisc_detach(self.if_index, &self.attach_type, self.priority) }
.map_err(|io_error| TcError::NetlinkError { io_error })?;
unsafe {
netlink_qdisc_detach(self.if_index, &self.attach_type, self.priority, self.handle)
}
.map_err(|io_error| TcError::NetlinkError { io_error })?;
Ok(())
}
}
@ -233,16 +269,16 @@ fn qdisc_detach_program_fast(
) -> Result<(), io::Error> {
let if_index = ifindex_from_ifname(if_name)? as i32;
let prios = unsafe { netlink_find_filter_with_name(if_index, attach_type, name)? };
if prios.is_empty() {
let filter_info = unsafe { netlink_find_filter_with_name(if_index, attach_type, name)? };
if filter_info.is_empty() {
return Err(io::Error::new(
io::ErrorKind::NotFound,
name.to_string_lossy(),
));
}
for prio in prios {
unsafe { netlink_qdisc_detach(if_index, &attach_type, prio)? };
for (prio, handle) in filter_info {
unsafe { netlink_qdisc_detach(if_index, &attach_type, prio, handle)? };
}
Ok(())

@ -104,7 +104,8 @@ pub(crate) unsafe fn netlink_qdisc_attach(
prog_fd: RawFd,
prog_name: &CStr,
priority: u16,
) -> Result<u16, io::Error> {
handle: u32,
) -> Result<(u16, u32), io::Error> {
let sock = NetlinkSocket::open()?;
let mut req = mem::zeroed::<TcRequest>();
@ -117,7 +118,7 @@ pub(crate) unsafe fn netlink_qdisc_attach(
nlmsg_seq: 1,
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
req.tc_info.tcm_handle = 0; // auto-assigned, if not provided
req.tc_info.tcm_handle = handle; // auto-assigned, if zero
req.tc_info.tcm_ifindex = if_index;
req.tc_info.tcm_parent = attach_type.parent();
req.tc_info.tcm_info = tc_handler_make((priority as u32) << 16, htons(ETH_P_ALL as u16) as u32);
@ -138,17 +139,14 @@ pub(crate) unsafe fn netlink_qdisc_attach(
req.header.nlmsg_len += align_to(kind_len + options_len, NLA_ALIGNTO as usize) as u32;
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
// find the RTM_NEWTFILTER reply and read the tcm_info field which we'll
// need to detach
let tc_info = match sock
// find the RTM_NEWTFILTER reply and read the tcm_info and tcm_handle fields
// which we'll need to detach
let tc_msg = match sock
.recv()?
.iter()
.find(|reply| reply.header.nlmsg_type == RTM_NEWTFILTER)
{
Some(reply) => {
let msg = ptr::read_unaligned(reply.data.as_ptr() as *const tcmsg);
msg.tcm_info
}
Some(reply) => ptr::read_unaligned(reply.data.as_ptr() as *const tcmsg),
None => {
// if sock.recv() succeeds we should never get here unless there's a
// bug in the kernel
@ -159,14 +157,15 @@ pub(crate) unsafe fn netlink_qdisc_attach(
}
};
let priority = ((tc_info & TC_H_MAJ_MASK) >> 16) as u16;
Ok(priority)
let priority = ((tc_msg.tcm_info & TC_H_MAJ_MASK) >> 16) as u16;
Ok((priority, tc_msg.tcm_handle))
}
pub(crate) unsafe fn netlink_qdisc_detach(
if_index: i32,
attach_type: &TcAttachType,
priority: u16,
handle: u32,
) -> Result<(), io::Error> {
let sock = NetlinkSocket::open()?;
let mut req = mem::zeroed::<TcRequest>();
@ -180,7 +179,7 @@ pub(crate) unsafe fn netlink_qdisc_detach(
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
req.tc_info.tcm_handle = 0; // auto-assigned, if not provided
req.tc_info.tcm_handle = handle; // auto-assigned, if zero
req.tc_info.tcm_info = tc_handler_make((priority as u32) << 16, htons(ETH_P_ALL as u16) as u32);
req.tc_info.tcm_parent = attach_type.parent();
req.tc_info.tcm_ifindex = if_index;
@ -192,11 +191,12 @@ pub(crate) unsafe fn netlink_qdisc_detach(
Ok(())
}
// Returns a vector of tuple (priority, handle) for filters matching the provided parameters
pub(crate) unsafe fn netlink_find_filter_with_name(
if_index: i32,
attach_type: TcAttachType,
name: &CStr,
) -> Result<Vec<u16>, io::Error> {
) -> Result<Vec<(u16, u32)>, io::Error> {
let mut req = mem::zeroed::<TcRequest>();
let nlmsg_len = mem::size_of::<nlmsghdr>() + mem::size_of::<tcmsg>();
@ -208,14 +208,14 @@ pub(crate) unsafe fn netlink_find_filter_with_name(
nlmsg_seq: 1,
};
req.tc_info.tcm_family = AF_UNSPEC as u8;
req.tc_info.tcm_handle = 0; // auto-assigned, if not provided
req.tc_info.tcm_handle = 0; // auto-assigned, if zero
req.tc_info.tcm_ifindex = if_index;
req.tc_info.tcm_parent = attach_type.parent();
let sock = NetlinkSocket::open()?;
sock.send(&bytes_of(&req)[..req.header.nlmsg_len as usize])?;
let mut prios = Vec::new();
let mut filter_info = Vec::new();
for msg in sock.recv()? {
if msg.header.nlmsg_type != RTM_NEWTFILTER {
continue;
@ -230,14 +230,14 @@ pub(crate) unsafe fn netlink_find_filter_with_name(
if let Some(f_name) = opts.get(&(TCA_BPF_NAME as u16)) {
if let Ok(f_name) = CStr::from_bytes_with_nul(f_name.data) {
if name == f_name {
prios.push(priority);
filter_info.push((priority, tc_msg.tcm_handle));
}
}
}
}
}
Ok(prios)
Ok(filter_info)
}
#[repr(C)]

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