programs: xdp: support detaching with FdLink

src/programs/xdp.rs

@@ -1,11 +1,11 @@
-use std::ffi::CString;
+use std::{cell::RefCell, ffi::CString, rc::Rc};
 
 use libc::if_nametoindex;
 
 use crate::RawFd;
 use crate::{
     generated::{bpf_attach_type::BPF_XDP, bpf_prog_type::BPF_PROG_TYPE_XDP},
-    programs::{load_program, ProgramData, ProgramError},
+    programs::{load_program, FdLink, Link, LinkRef, ProgramData, ProgramError},
     syscalls::bpf_link_create,
 };
 
@@ -23,7 +23,7 @@ impl Xdp {
         self.data.name.to_string()
     }
 
-    pub fn attach(&self, interface: &str) -> Result<(), ProgramError> {
+    pub fn attach(&mut self, interface: &str) -> Result<impl Link, ProgramError> {
         let prog_fd = self.data.fd_or_err()?;
 
         let c_interface = CString::new(interface).unwrap();
@@ -39,8 +39,10 @@ impl Xdp {
                 program: self.name(),
                 io_error,
             }
-        })?;
+        })? as RawFd;
+        let link = Rc::new(RefCell::new(FdLink { fd: Some(link_fd) }));
+        self.data.links.push(link.clone());
 
-        Ok(())
+        Ok(LinkRef::new(&link))
     }
 }