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[216] Add Support For Flow Dissector Programs
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,66 @@ | ||
| use proc_macro2::TokenStream; | ||
| use proc_macro_error::abort; | ||
| use quote::quote; | ||
| use syn::{ItemFn, Result}; | ||
|
|
||
| pub(crate) struct FlowDissector { | ||
| item: ItemFn, | ||
| } | ||
|
|
||
| impl FlowDissector { | ||
| pub(crate) fn parse(attrs: TokenStream, item: TokenStream) -> Result<Self> { | ||
| if !attrs.is_empty() { | ||
| abort!(attrs, "unexpected attribute") | ||
| } | ||
| let item = syn::parse2(item)?; | ||
| Ok(FlowDissector { item }) | ||
| } | ||
|
|
||
| pub(crate) fn expand(&self) -> Result<TokenStream> { | ||
| let fn_name = self.item.sig.ident.clone(); | ||
| let fn_vis = &self.item.vis; | ||
| let item = &self.item; | ||
| Ok(quote! { | ||
| #[no_mangle] | ||
| #[link_section = "flow_dissector"] | ||
| #fn_vis fn #fn_name(ctx: *mut ::aya_bpf::bindings::__sk_buff) -> u32 { | ||
| return #fn_name(::aya_bpf::programs::FlowDissectorContext::new(ctx)); | ||
|
|
||
| #item | ||
| } | ||
| }) | ||
| } | ||
| } | ||
|
|
||
| #[cfg(test)] | ||
| mod tests { | ||
| use syn::parse_quote; | ||
|
|
||
| use super::*; | ||
|
|
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| #[test] | ||
| fn test_flow_dissector() { | ||
| let prog = FlowDissector::parse( | ||
| parse_quote! {}, | ||
| parse_quote! { | ||
| fn prog(ctx: &mut ::aya_bpf::programs::FlowDissectorContext) -> u32 { | ||
| 0 | ||
| } | ||
| }, | ||
| ) | ||
| .unwrap(); | ||
| let expanded = prog.expand().unwrap(); | ||
| let expected = quote! { | ||
| #[no_mangle] | ||
| #[link_section = "flow_dissector"] | ||
| fn prog(ctx: *mut ::aya_bpf::bindings::__sk_buff) -> u32 { | ||
| return prog(::aya_bpf::programs::FlowDissectorContext::new(ctx)); | ||
|
|
||
| fn prog(ctx: &mut ::aya_bpf::programs::FlowDissectorContext) -> u32 { | ||
| 0 | ||
| } | ||
| } | ||
| }; | ||
| assert_eq!(expected.to_string(), expanded.to_string()); | ||
| } | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,109 @@ | ||
| //! Flow dissector programs. | ||
| use std::os::fd::AsFd; | ||
|
|
||
| use crate::{ | ||
| generated::{bpf_attach_type::BPF_FLOW_DISSECTOR, bpf_prog_type::BPF_PROG_TYPE_FLOW_DISSECTOR}, | ||
| programs::{define_link_wrapper, load_program, FdLink, FdLinkId, ProgramData, ProgramError}, | ||
| sys::{bpf_link_create, LinkTarget, SyscallError}, | ||
| }; | ||
|
|
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| /// A program that can be attached as a Flow Dissector routine | ||
| /// | ||
| /// ['FlowDissector'] programs operate on an __sk_buff. | ||
| /// However, only the limited set of fields is allowed: data, data_end and flow_keys. | ||
| /// flow_keys is struct bpf_flow_keys and contains flow dissector input and output arguments. | ||
| /// | ||
| /// # Minimum kernel version | ||
| /// | ||
| /// The minimum kernel version required to use this feature is 4.2. | ||
| /// | ||
| /// # 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 = Bpf::load_file("ebpf_programs.o")?; | ||
| /// use aya::{Bpf, programs::FlowDissector}; | ||
| /// use std::fs::File; | ||
| /// | ||
| /// let program: &mut FlowDissector = bpf.program_mut("filename_lookup").unwrap().try_into()?; | ||
| /// program.load()?; | ||
| /// | ||
| /// let net_ns = File::open("/proc/self/ns/net")?; | ||
| /// program.attach(net_ns)?; | ||
| /// # Ok::<(), Error>(()) | ||
| /// ``` | ||
| #[derive(Debug)] | ||
| #[doc(alias = "BPF_PROG_TYPE_FLOW_DISSECTOR")] | ||
| pub struct FlowDissector { | ||
| pub(crate) data: ProgramData<FlowDissectorLink>, | ||
| } | ||
|
|
||
| impl FlowDissector { | ||
| /// Loads the program inside the kernel. | ||
| pub fn load(&mut self) -> Result<(), ProgramError> { | ||
| self.data.expected_attach_type = Some(BPF_FLOW_DISSECTOR); | ||
| load_program(BPF_PROG_TYPE_FLOW_DISSECTOR, &mut self.data) | ||
| } | ||
|
|
||
| /// Attaches the program to the given network namespace. | ||
| /// | ||
| /// The returned value can be used to detach, see [FlowDissector::detach]. | ||
| pub fn attach<T: AsFd>(&mut self, netns: T) -> Result<FlowDissectorLinkId, ProgramError> { | ||
| let prog_fd = self.fd()?; | ||
| let prog_fd = prog_fd.as_fd(); | ||
| let netns_fd = netns.as_fd(); | ||
|
|
||
| let link_fd = bpf_link_create( | ||
| prog_fd, | ||
| LinkTarget::Fd(netns_fd), | ||
| BPF_FLOW_DISSECTOR, | ||
| None, | ||
| 0, | ||
| ) | ||
| .map_err(|(_, io_error)| SyscallError { | ||
| call: "bpf_link_create", | ||
| io_error, | ||
| })?; | ||
| self.data | ||
| .links | ||
| .insert(FlowDissectorLink::new(FdLink::new(link_fd))) | ||
| } | ||
|
|
||
| /// Detaches the program. | ||
| /// | ||
| /// See [FlowDissector::attach]. | ||
| pub fn detach(&mut self, link_id: FlowDissectorLinkId) -> Result<(), ProgramError> { | ||
| self.data.links.remove(link_id) | ||
| } | ||
|
|
||
| /// 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: FlowDissectorLinkId, | ||
| ) -> Result<FlowDissectorLink, ProgramError> { | ||
| self.data.take_link(link_id) | ||
| } | ||
| } | ||
|
|
||
| define_link_wrapper!( | ||
| /// The link used by [FlowDissector] programs. | ||
| FlowDissectorLink, | ||
| /// The type returned by [FlowDissector::attach]. Can be passed to [FlowDissector::detach]. | ||
| FlowDissectorLinkId, | ||
| FdLink, | ||
| FdLinkId | ||
| ); |
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