aya: Add probe for bpf_get_attach_cookie

Signed-off-by: Dave Tucker <dave@dtucker.co.uk>

aya/src/bpf.rs

@@ -28,10 +28,10 @@ use crate::{
         SkSkbKind, SockOps, SocketFilter, TracePoint, UProbe, Xdp,
     },
     sys::{
-        bpf_load_btf, bpf_map_freeze, bpf_map_update_elem_ptr, is_btf_datasec_supported,
-        is_btf_decl_tag_supported, is_btf_float_supported, is_btf_func_global_supported,
-        is_btf_func_supported, is_btf_supported, is_btf_type_tag_supported, is_prog_name_supported,
-        retry_with_verifier_logs,
+        bpf_load_btf, bpf_map_freeze, bpf_map_update_elem_ptr, is_bpf_cookie_supported,
+        is_btf_datasec_supported, is_btf_decl_tag_supported, is_btf_float_supported,
+        is_btf_func_global_supported, is_btf_func_supported, is_btf_supported,
+        is_btf_type_tag_supported, is_prog_name_supported, retry_with_verifier_logs,
     },
     util::{bytes_of, possible_cpus, VerifierLog, POSSIBLE_CPUS},
 };
@@ -120,6 +120,7 @@ impl Default for PinningType {
 #[derive(Default, Debug)]
 pub(crate) struct Features {
     pub bpf_name: bool,
+    pub bpf_cookie: bool,
     pub btf: bool,
     pub btf_func: bool,
     pub btf_func_global: bool,
@@ -134,6 +135,9 @@ impl Features {
         self.bpf_name = is_prog_name_supported();
         debug!("[FEAT PROBE] BPF program name support: {}", self.bpf_name);
 
+        self.bpf_cookie = is_bpf_cookie_supported();
+        debug!("[FEAT PROBE] BPF cookie support: {}", self.bpf_cookie);
+
         self.btf = is_btf_supported();
         debug!("[FEAT PROBE] BTF support: {}", self.btf);
 

aya/src/sys/bpf.rs

@@ -571,6 +571,33 @@ pub(crate) fn is_prog_name_supported() -> bool {
     }
 }
 
+pub(crate) fn is_bpf_cookie_supported() -> bool {
+    let mut attr = unsafe { mem::zeroed::<bpf_attr>() };
+    let u = unsafe { &mut attr.__bindgen_anon_3 };
+
+    let prog: &[u8] = &[
+        0x85, 0x00, 0x00, 0x00, 0xae, 0x00, 0x00, 0x00, // call bpf_get_attach_cookie
+        0x95, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, // exit
+    ];
+
+    let gpl = b"GPL\0";
+    u.license = gpl.as_ptr() as u64;
+
+    let insns = copy_instructions(prog).unwrap();
+    u.insn_cnt = insns.len() as u32;
+    u.insns = insns.as_ptr() as u64;
+    u.prog_type = bpf_prog_type::BPF_PROG_TYPE_KPROBE as u32;
+
+    match sys_bpf(bpf_cmd::BPF_PROG_LOAD, &attr) {
+        Ok(v) => {
+            let fd = v as RawFd;
+            unsafe { close(fd) };
+            true
+        }
+        Err(_) => false,
+    }
+}
+
 pub(crate) fn is_btf_supported() -> bool {
     let mut btf = Btf::new();
     let name_offset = btf.add_string("int".to_string());