mirror of https://github.com/aya-rs/aya
ebpf: Add TcContext for classifier programs
This change separates the previous `SkBuffContext` into three structs: * `SkBuff` which is a wrapper around `__sk_buff` which contains all possible methods operating on it. * `SkBuffContext` which is a program context for programs which **cannot** access `__sk_buff` directly and instead can only use `load_bytes`. * `TcContext` which is a classifier context which can access `__sk_buff` directly, hence exposes `data` and `data_end`. Signed-off-by: Michal Rostecki <vadorovsky@gmail.com>pull/352/head
Michal Rostecki
3 years ago
parent
945169996c
commit
895f96e971
@ -0,0 +1,184 @@
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use aya_bpf_cty::{c_long, c_void};
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use crate::{bindings::__sk_buff, programs::sk_buff::SkBuff, BpfContext};
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pub struct TcContext {
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pub skb: SkBuff,
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}
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impl TcContext {
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pub fn new(skb: *mut __sk_buff) -> TcContext {
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let skb = SkBuff { skb };
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TcContext { skb }
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}
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#[allow(clippy::len_without_is_empty)]
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#[inline]
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pub fn len(&self) -> u32 {
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self.skb.len()
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}
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#[inline]
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pub fn data(&self) -> usize {
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self.skb.data()
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}
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#[inline]
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pub fn data_end(&self) -> usize {
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self.skb.data_end()
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}
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#[inline]
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pub fn set_mark(&mut self, mark: u32) {
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self.skb.set_mark(mark)
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}
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#[inline]
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pub fn cb(&self) -> &[u32] {
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self.skb.cb()
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}
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#[inline]
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pub fn cb_mut(&mut self) -> &mut [u32] {
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self.skb.cb_mut()
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}
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/// Returns the owner UID of the socket associated to the SKB context.
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#[inline]
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pub fn get_socket_uid(&self) -> u32 {
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self.skb.get_socket_uid()
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}
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#[inline]
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pub fn load<T>(&self, offset: usize) -> Result<T, c_long> {
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self.skb.load(offset)
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}
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/// Reads some bytes from the packet into the specified buffer, returning
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/// how many bytes were read.
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///
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/// Starts reading at `offset` and reads at most `dst.len()` or
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/// `self.len() - offset` bytes, depending on which one is smaller.
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///
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/// # Examples
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///
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/// Read into a `PerCpuArray`.
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///
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/// ```no_run
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/// use core::mem;
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///
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/// use aya_bpf::{bindings::TC_ACT_PIPE, macros::map, maps::PerCpuArray, programs::TcContext};
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/// # #[allow(non_camel_case_types)]
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/// # struct ethhdr {};
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/// # #[allow(non_camel_case_types)]
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/// # struct iphdr {};
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/// # #[allow(non_camel_case_types)]
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/// # struct tcphdr {};
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///
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/// const ETH_HDR_LEN: usize = mem::size_of::<ethhdr>();
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/// const IP_HDR_LEN: usize = mem::size_of::<iphdr>();
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/// const TCP_HDR_LEN: usize = mem::size_of::<tcphdr>();
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///
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/// #[repr(C)]
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/// pub struct Buf {
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/// pub buf: [u8; 1500],
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/// }
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///
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/// #[map]
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/// pub static mut BUF: PerCpuArray<Buf> = PerCpuArray::with_max_entries(1, 0);
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///
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/// fn try_classifier(ctx: TcContext) -> Result<i32, i32> {
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/// let buf = unsafe {
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/// let ptr = BUF.get_ptr_mut(0).ok_or(TC_ACT_PIPE)?;
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/// &mut *ptr
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/// };
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/// let offset = ETH_HDR_LEN + IP_HDR_LEN + TCP_HDR_LEN;
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/// ctx.load_bytes(offset, &mut buf.buf).map_err(|_| TC_ACT_PIPE)?;
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///
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/// // do something with `buf`
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///
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/// Ok(TC_ACT_PIPE)
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/// }
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/// ```
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#[inline(always)]
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pub fn load_bytes(&self, offset: usize, dst: &mut [u8]) -> Result<usize, c_long> {
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self.skb.load_bytes(offset, dst)
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}
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#[inline]
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pub fn store<T>(&mut self, offset: usize, v: &T, flags: u64) -> Result<(), c_long> {
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self.skb.store(offset, v, flags)
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}
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#[inline]
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pub fn l3_csum_replace(
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&self,
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offset: usize,
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from: u64,
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to: u64,
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size: u64,
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) -> Result<(), c_long> {
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self.skb.l3_csum_replace(offset, from, to, size)
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}
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#[inline]
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pub fn l4_csum_replace(
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&self,
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offset: usize,
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from: u64,
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to: u64,
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flags: u64,
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) -> Result<(), c_long> {
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self.skb.l4_csum_replace(offset, from, to, flags)
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}
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#[inline]
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pub fn adjust_room(&self, len_diff: i32, mode: u32, flags: u64) -> Result<(), c_long> {
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self.skb.adjust_room(len_diff, mode, flags)
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}
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#[inline]
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pub fn clone_redirect(&self, if_index: u32, flags: u64) -> Result<(), c_long> {
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self.skb.clone_redirect(if_index, flags)
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}
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#[inline]
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pub fn change_type(&self, ty: u32) -> Result<(), c_long> {
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self.skb.change_type(ty)
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}
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/// Pulls in non-linear data in case the skb is non-linear.
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///
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/// Make len bytes from skb readable and writable. If a zero value is passed for
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/// `len`, then the whole length of the skb is pulled. This helper is only needed
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/// for reading and writing with direct packet access.
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///
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/// # Examples
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///
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/// ```no_run
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/// mod bindings;
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/// use bindings::{ethhdr, iphdr, udphdr};
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///
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/// const ETH_HLEN: usize = core::mem::size_of::<ethhdr>();
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/// const IP_HLEN: usize = core::mem::size_of::<iphdr>();
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/// const UDP_HLEN: usize = core::mem::size_of::<udphdr>();
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///
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/// fn try_classifier(ctx: TcContext) -> Result<i32, i32> {
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/// let len = ETH_HLEN + IP_HLEN + UDP_HLEN;
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/// match ctx.pull_data(len as u32) {
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/// Ok(_) => return Ok(0),
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/// Err(ret) => return Err(ret as i32),
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/// }
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/// }
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/// ```
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#[inline(always)]
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pub fn pull_data(&self, len: u32) -> Result<(), c_long> {
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self.skb.pull_data(len)
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}
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}
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impl BpfContext for TcContext {
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fn as_ptr(&self) -> *mut c_void {
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self.skb.as_ptr()
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}
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}
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