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koonwenkoonwen
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Merge pull request #3 from Hevienz/main
add xdp support
2 parents 298b1b7 + 4fd20c7 commit 42eb2ca

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8 files changed

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‎CHANGES.md

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## v0.1.1 (2024-07-05)
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- Improve documentation
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- Add XDP support (@Hevienz)
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- `bpf_xdp_attach`
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- `bpf_xdp_detach`
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## v0.1.0 (2024-07-01)
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- Initial release.

‎examples/Makefile

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@@ -9,6 +9,9 @@ minimal: build
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kprobe: build
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sudo $(CWD)/kprobe.exe
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xdp_counter: build
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sudo $(CWD)/xdp_counter.exe
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tc: build
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sudo $(CWD)/tc.exe
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‎examples/dune

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(executables
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(names tc bootstrap bootstrap_c kprobe minimal)
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(names tc bootstrap bootstrap_c kprobe minimal xdp_counter)
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(libraries libbpf libbpf_maps))
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; Below is repetitive build rules to compile *.bpf.c eBPF C source code that runs in the kernel
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(system
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"clang -g -O2 -target bpf -I/usr/include/%{architecture}-linux-gnu/ -c kprobe.bpf.c -D__TARGET_ARCH_%{read:arch}")))
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(rule
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(mode
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(promote (until-clean)))
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(targets xdp_counter.bpf.o)
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(deps arch xdp_counter.bpf.c)
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(action
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(system
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"clang -g -O2 -target bpf -I/usr/include/%{architecture}-linux-gnu/ -c xdp_counter.bpf.c -D__TARGET_ARCH_%{read:arch}")))
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(rule
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(mode
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(promote (until-clean)))

‎examples/xdp_counter.bpf.c

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// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__type(key, int);
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__type(value, unsigned long);
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} packet_count SEC(".maps");
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SEC("xdp")
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int count_packets(struct xdp_md *ctx) {
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int key = 0;
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unsigned long *value;
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value = bpf_map_lookup_elem(&packet_count, &key);
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if (value)
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__sync_fetch_and_add(value, 1);
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return XDP_PASS;
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}
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char _license[] SEC("license") = "GPL";

‎examples/xdp_counter.ml

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open Libbpf
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let obj_path = "xdp_counter.bpf.o"
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let program_name = "count_packets"
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let map = "packet_count"
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let ifindex = 1 (* Usually localhost *)
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let load_and_attach_xdp ifindex =
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(* Load the compiled eBPF object *)
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let obj = bpf_object_open obj_path in
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let _ = bpf_object_load obj in
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let program = bpf_object_find_program_by_name obj program_name in
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let fd = bpf_program_fd program in
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let opts = Ctypes.from_voidp C.Types.Bpf_xdp.Attach_opts.t Ctypes.null in
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(match C.Functions.bpf_xdp_attach ifindex fd Unsigned.UInt32.zero opts with
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| 0 -> ()
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| _ ->
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bpf_object_close obj;
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failwith "Failed to attach xdp program");
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(obj, opts)
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let teardown_xdp (obj, link) =
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let _ = C.Functions.bpf_xdp_detach 0 Unsigned.UInt32.zero link in
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bpf_object_close obj
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let () =
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let obj, link = load_and_attach_xdp ifindex in
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(* Initialize bpf_map with value, if not the lookup will fail *)
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let counter = bpf_object_find_map_by_name obj map in
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let exitting = ref false in
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let sig_handler = Sys.Signal_handle (fun _ -> exitting := true) in
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Sys.(set_signal sigint sig_handler);
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Sys.(set_signal sigterm sig_handler);
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let rec loop () =
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if !exitting then ()
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else (
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Unix.sleep 1;
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let count =
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bpf_map_lookup_value ~key_ty:Ctypes.int ~val_ty:Ctypes.ulong
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~val_zero:Unsigned.ULong.zero counter 0
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in
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Printf.printf "Packet count %d\n%!" (Unsigned.ULong.to_int count);
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loop ())
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in
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loop ();
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teardown_xdp (obj, link)

‎src/bindings/c_function_description.ml

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foreign "bpf_map__delete_elem"
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(ptr Types.bpf_map @-> ptr void @-> size_t @-> uint64_t @-> returning int)
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(* ================================== Xdp ================================== *)
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let bpf_xdp_attach =
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foreign "bpf_xdp_attach"
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(int @-> int @-> uint32_t
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@-> ptr Types.Bpf_xdp.Attach_opts.t
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@-> returning int)
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let bpf_xdp_detach =
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foreign "bpf_xdp_detach"
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(int @-> uint32_t @-> ptr Types.Bpf_xdp.Attach_opts.t @-> returning int)
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(* ================================== Traffic control ================================== *)
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let bpf_tc_hook_create =

‎src/bindings/c_type_description.ml

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let ring_buffer_opts : [ `Ring_buffer_opts ] structure typ =
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structure "ring_buffer_opts"
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module Bpf_xdp = struct
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module Attach_opts = struct
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let t : [ `Attach_opts ] structure typ = structure "bpf_xdp_attach_opts"
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let ( -: ) ty label = field t label ty
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let sz = size_t -: "sz"
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let old_prog_fd = int -: "old_prog_fd"
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let () = seal t
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end
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end
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module Bpf_tc = struct
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let attach_point : [ `INGRESS | `EGRESS | `CUSTOM ] typ =
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let def = c ~prefix:"BPF_TC_" in

‎supported.json

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{
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"ocaml_libbpf.1.1": [
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"bpf_xdp_attach",
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"bpf_xdp_detach"
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],
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"ocaml_libbpf.1.0": [
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"libbpf_major_version",
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"libbpf_minor_version",

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