Commit 1d671166 authored by Yonghong Song's avatar Yonghong Song Committed by Andrii Nakryiko
Browse files

libbpf: Support link-based cgroup attach with options 



Currently libbpf supports bpf_program__attach_cgroup() with signature:
  LIBBPF_API struct bpf_link *
  bpf_program__attach_cgroup(const struct bpf_program *prog, int cgroup_fd);

To support mprog style attachment, additionsl fields like flags,
relative_{fd,id} and expected_revision are needed.

Add a new API:
  LIBBPF_API struct bpf_link *
  bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,
                                  const struct bpf_cgroup_opts *opts);
where bpf_cgroup_opts contains all above needed fields.

Signed-off-by: default avatarYonghong Song <yonghong.song@linux.dev>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20250606163146.2429212-1-yonghong.song@linux.dev
parent 12093398

tools/lib/bpf/bpf.c

+44 −0
Original line number Diff line number Diff line
@@ -837,6 +837,50 @@ int bpf_link_create(int prog_fd, int target_fd, 
		if (!OPTS_ZEROED(opts, netkit))

			return libbpf_err(-EINVAL);

		break;

	case BPF_CGROUP_INET_INGRESS:

	case BPF_CGROUP_INET_EGRESS:

	case BPF_CGROUP_INET_SOCK_CREATE:

	case BPF_CGROUP_INET_SOCK_RELEASE:

	case BPF_CGROUP_INET4_BIND:

	case BPF_CGROUP_INET6_BIND:

	case BPF_CGROUP_INET4_POST_BIND:

	case BPF_CGROUP_INET6_POST_BIND:

	case BPF_CGROUP_INET4_CONNECT:

	case BPF_CGROUP_INET6_CONNECT:

	case BPF_CGROUP_UNIX_CONNECT:

	case BPF_CGROUP_INET4_GETPEERNAME:

	case BPF_CGROUP_INET6_GETPEERNAME:

	case BPF_CGROUP_UNIX_GETPEERNAME:

	case BPF_CGROUP_INET4_GETSOCKNAME:

	case BPF_CGROUP_INET6_GETSOCKNAME:

	case BPF_CGROUP_UNIX_GETSOCKNAME:

	case BPF_CGROUP_UDP4_SENDMSG:

	case BPF_CGROUP_UDP6_SENDMSG:

	case BPF_CGROUP_UNIX_SENDMSG:

	case BPF_CGROUP_UDP4_RECVMSG:

	case BPF_CGROUP_UDP6_RECVMSG:

	case BPF_CGROUP_UNIX_RECVMSG:

	case BPF_CGROUP_SOCK_OPS:

	case BPF_CGROUP_DEVICE:

	case BPF_CGROUP_SYSCTL:

	case BPF_CGROUP_GETSOCKOPT:

	case BPF_CGROUP_SETSOCKOPT:

	case BPF_LSM_CGROUP:

		relative_fd = OPTS_GET(opts, cgroup.relative_fd, 0);

		relative_id = OPTS_GET(opts, cgroup.relative_id, 0);

		if (relative_fd && relative_id)

			return libbpf_err(-EINVAL);

		if (relative_id) {

			attr.link_create.cgroup.relative_id = relative_id;

			attr.link_create.flags |= BPF_F_ID;

		} else {

			attr.link_create.cgroup.relative_fd = relative_fd;

		}

		attr.link_create.cgroup.expected_revision =

			OPTS_GET(opts, cgroup.expected_revision, 0);

		if (!OPTS_ZEROED(opts, cgroup))

			return libbpf_err(-EINVAL);

		break;

	default:

		if (!OPTS_ZEROED(opts, flags))

			return libbpf_err(-EINVAL);

tools/lib/bpf/bpf.h

+5 −0
Original line number Diff line number Diff line
@@ -438,6 +438,11 @@ struct bpf_link_create_opts { 
			__u32 relative_id;

			__u64 expected_revision;

		} netkit;

		struct {

			__u32 relative_fd;

			__u32 relative_id;

			__u64 expected_revision;

		} cgroup;

	};

	size_t :0;

};

tools/lib/bpf/libbpf.c

+28 −0
Original line number Diff line number Diff line
@@ -12837,6 +12837,34 @@ struct bpf_link *bpf_program__attach_xdp(const struct bpf_program *prog, int ifi 
	return bpf_program_attach_fd(prog, ifindex, "xdp", NULL);

}



struct bpf_link *

bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,

				const struct bpf_cgroup_opts *opts)

{

	LIBBPF_OPTS(bpf_link_create_opts, link_create_opts);

	__u32 relative_id;

	int relative_fd;



	if (!OPTS_VALID(opts, bpf_cgroup_opts))

		return libbpf_err_ptr(-EINVAL);



	relative_id = OPTS_GET(opts, relative_id, 0);

	relative_fd = OPTS_GET(opts, relative_fd, 0);



	if (relative_fd && relative_id) {

		pr_warn("prog '%s': relative_fd and relative_id cannot be set at the same time\n",

			prog->name);

		return libbpf_err_ptr(-EINVAL);

	}



	link_create_opts.cgroup.expected_revision = OPTS_GET(opts, expected_revision, 0);

	link_create_opts.cgroup.relative_fd = relative_fd;

	link_create_opts.cgroup.relative_id = relative_id;

	link_create_opts.flags = OPTS_GET(opts, flags, 0);



	return bpf_program_attach_fd(prog, cgroup_fd, "cgroup", &link_create_opts);

}



struct bpf_link *

bpf_program__attach_tcx(const struct bpf_program *prog, int ifindex,

			const struct bpf_tcx_opts *opts)

tools/lib/bpf/libbpf.h

+15 −0
Original line number Diff line number Diff line
@@ -877,6 +877,21 @@ LIBBPF_API struct bpf_link * 
bpf_program__attach_netkit(const struct bpf_program *prog, int ifindex,

			   const struct bpf_netkit_opts *opts);



struct bpf_cgroup_opts {

	/* size of this struct, for forward/backward compatibility */

	size_t sz;

	__u32 flags;

	__u32 relative_fd;

	__u32 relative_id;

	__u64 expected_revision;

	size_t :0;

};

#define bpf_cgroup_opts__last_field expected_revision



LIBBPF_API struct bpf_link *

bpf_program__attach_cgroup_opts(const struct bpf_program *prog, int cgroup_fd,

				const struct bpf_cgroup_opts *opts);



struct bpf_map;



LIBBPF_API struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map);

tools/lib/bpf/libbpf.map

+1 −0
Original line number Diff line number Diff line
@@ -437,6 +437,7 @@ LIBBPF_1.6.0 { 
		bpf_linker__add_fd;

		bpf_linker__new_fd;

		bpf_object__prepare;

		bpf_program__attach_cgroup_opts;

		bpf_program__func_info;

		bpf_program__func_info_cnt;

		bpf_program__line_info;