[wip] devices: annotate new bpf functions

Link to cilium/ebpf analogs.

Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>

Author: kolyshkin

devices/ebpf_linux.go

@@ -24,6 +24,9 @@ func bpf(cmd uintptr, attr unsafe.Pointer, size uintptr) (uintptr, error) {
 }
 
 // bpfProgLoad loads a BPF_PROG_TYPE_CGROUP_DEVICE program and returns its fd.
+//
+// It is roughly equivalent to [github.com/cilium/ebpf/internal/sys.ProgLoad],
+// and the "retry with verifier log" is taken from [github.com/cilium/ebpf.NewProgram].
 func bpfProgLoad(insns asm.Instructions, license string) (int, error) {
 	buf := bytes.NewBuffer(make([]byte, 0, insns.Size()))
 	if err := insns.Marshal(buf, nativeEndian); err != nil {
@@ -84,6 +87,8 @@ func bpfProgLoad(insns asm.Instructions, license string) (int, error) {
 }
 
 // bpfProgGetFdByID returns the fd for the BPF program with the given ID.
+//
+// It is roughly equivalent to [github.com/cilium/ebpf/internal/sys.ProgGetFdById].
 func bpfProgGetFdByID(id uint32) (int, error) {
 	// The kernel zero-fills the rest of bpf_attr beyond the size we pass.
 	attr := struct{ id uint32 }{id}
@@ -96,6 +101,8 @@ func bpfProgGetFdByID(id uint32) (int, error) {
 
 // bpfProgAttach attaches progFd to cgroupFd with the given flags. If replaceFd
 // is >= 0, its fd is set in replaceBpfFd (for BPF_F_REPLACE semantics).
+//
+// It is roughly equivalent to [github.com/cilium/ebpf/link.RawAttachProgram].
 func bpfProgAttach(cgroupFd, progFd int, attachFlags uint32, replaceFd int) error {
 	attr := struct {
 		targetFd     uint32
@@ -117,6 +124,8 @@ func bpfProgAttach(cgroupFd, progFd int, attachFlags uint32, replaceFd int) erro
 }
 
 // bpfProgDetach detaches progFd from cgroupFd.
+//
+// It is roughly equivalent to [github.com/cilium/ebpf/link.RawDetachProgram].
 func bpfProgDetach(cgroupFd, progFd int) error {
 	// The kernel zero-fills the rest of bpf_attr beyond the size we pass.
 	attr := struct {