Commit fe20ce3a authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov
Browse files

libbpf: Add opts-based attach/detach/query API for tcx 



Extend libbpf attach opts and add a new detach opts API so this can be used
to add/remove fd-based tcx BPF programs. The old-style bpf_prog_detach() and
bpf_prog_detach2() APIs are refactored to reuse the new bpf_prog_detach_opts()
internally.

The bpf_prog_query_opts() API got extended to be able to handle the new
link_ids, link_attach_flags and revision fields.

For concrete usage examples, see the extensive selftests that have been
developed as part of this series.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230719140858.13224-4-daniel@iogearbox.net


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent e420bed0

tools/lib/bpf/bpf.c

+71 −36
Original line number Diff line number Diff line
@@ -629,57 +629,91 @@ int bpf_prog_attach(int prog_fd, int target_fd, enum bpf_attach_type type, 
	return bpf_prog_attach_opts(prog_fd, target_fd, type, &opts);

}



int bpf_prog_attach_opts(int prog_fd, int target_fd,

			  enum bpf_attach_type type,

int bpf_prog_attach_opts(int prog_fd, int target, enum bpf_attach_type type,

			 const struct bpf_prog_attach_opts *opts)

{

	const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);

	const size_t attr_sz = offsetofend(union bpf_attr, expected_revision);

	__u32 relative_id, flags;

	int ret, relative_fd;

	union bpf_attr attr;

	int ret;



	if (!OPTS_VALID(opts, bpf_prog_attach_opts))

		return libbpf_err(-EINVAL);



	relative_id = OPTS_GET(opts, relative_id, 0);

	relative_fd = OPTS_GET(opts, relative_fd, 0);

	flags = OPTS_GET(opts, flags, 0);



	/* validate we don't have unexpected combinations of non-zero fields */

	if (relative_fd && relative_id)

		return libbpf_err(-EINVAL);



	memset(&attr, 0, attr_sz);

	attr.target_fd	   = target_fd;

	attr.target_fd		= target;

	attr.attach_bpf_fd	= prog_fd;

	attr.attach_type	= type;

	attr.attach_flags  = OPTS_GET(opts, flags, 0);

	attr.replace_bpf_fd = OPTS_GET(opts, replace_prog_fd, 0);

	attr.replace_bpf_fd	= OPTS_GET(opts, replace_fd, 0);

	attr.expected_revision	= OPTS_GET(opts, expected_revision, 0);



	if (relative_id) {

		attr.attach_flags = flags | BPF_F_ID;

		attr.relative_id  = relative_id;

	} else {

		attr.attach_flags = flags;

		attr.relative_fd  = relative_fd;

	}



	ret = sys_bpf(BPF_PROG_ATTACH, &attr, attr_sz);

	return libbpf_err_errno(ret);

}



int bpf_prog_detach(int target_fd, enum bpf_attach_type type)

int bpf_prog_detach_opts(int prog_fd, int target, enum bpf_attach_type type,

			 const struct bpf_prog_detach_opts *opts)

{

	const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);

	const size_t attr_sz = offsetofend(union bpf_attr, expected_revision);

	__u32 relative_id, flags;

	int ret, relative_fd;

	union bpf_attr attr;

	int ret;



	memset(&attr, 0, attr_sz);

	attr.target_fd	 = target_fd;

	attr.attach_type = type;

	if (!OPTS_VALID(opts, bpf_prog_detach_opts))

		return libbpf_err(-EINVAL);



	ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);

	return libbpf_err_errno(ret);

}

	relative_id = OPTS_GET(opts, relative_id, 0);

	relative_fd = OPTS_GET(opts, relative_fd, 0);

	flags = OPTS_GET(opts, flags, 0);



int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)

{

	const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);

	union bpf_attr attr;

	int ret;

	/* validate we don't have unexpected combinations of non-zero fields */

	if (relative_fd && relative_id)

		return libbpf_err(-EINVAL);



	memset(&attr, 0, attr_sz);

	attr.target_fd	 = target_fd;

	attr.target_fd		= target;

	attr.attach_bpf_fd	= prog_fd;

	attr.attach_type	= type;

	attr.expected_revision	= OPTS_GET(opts, expected_revision, 0);



	if (relative_id) {

		attr.attach_flags = flags | BPF_F_ID;

		attr.relative_id  = relative_id;

	} else {

		attr.attach_flags = flags;

		attr.relative_fd  = relative_fd;

	}



	ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);

	return libbpf_err_errno(ret);

}



int bpf_prog_detach(int target_fd, enum bpf_attach_type type)

{

	return bpf_prog_detach_opts(0, target_fd, type, NULL);

}



int bpf_prog_detach2(int prog_fd, int target_fd, enum bpf_attach_type type)

{

	return bpf_prog_detach_opts(prog_fd, target_fd, type, NULL);

}



int bpf_link_create(int prog_fd, int target_fd,

		    enum bpf_attach_type attach_type,

		    const struct bpf_link_create_opts *opts)
@@ -841,8 +875,7 @@ int bpf_iter_create(int link_fd) 
	return libbpf_err_errno(fd);

}



int bpf_prog_query_opts(int target_fd,

			enum bpf_attach_type type,

int bpf_prog_query_opts(int target, enum bpf_attach_type type,

			struct bpf_prog_query_opts *opts)

{

	const size_t attr_sz = offsetofend(union bpf_attr, query);
@@ -853,18 +886,20 @@ int bpf_prog_query_opts(int target_fd, 
		return libbpf_err(-EINVAL);



	memset(&attr, 0, attr_sz);



	attr.query.target_fd	= target_fd;

	attr.query.target_fd		= target;

	attr.query.attach_type		= type;

	attr.query.query_flags		= OPTS_GET(opts, query_flags, 0);

	attr.query.prog_cnt	= OPTS_GET(opts, prog_cnt, 0);

	attr.query.count		= OPTS_GET(opts, count, 0);

	attr.query.prog_ids		= ptr_to_u64(OPTS_GET(opts, prog_ids, NULL));

	attr.query.link_ids		= ptr_to_u64(OPTS_GET(opts, link_ids, NULL));

	attr.query.prog_attach_flags	= ptr_to_u64(OPTS_GET(opts, prog_attach_flags, NULL));

	attr.query.link_attach_flags	= ptr_to_u64(OPTS_GET(opts, link_attach_flags, NULL));



	ret = sys_bpf(BPF_PROG_QUERY, &attr, attr_sz);



	OPTS_SET(opts, attach_flags, attr.query.attach_flags);

	OPTS_SET(opts, prog_cnt, attr.query.prog_cnt);

	OPTS_SET(opts, revision, attr.query.revision);

	OPTS_SET(opts, count, attr.query.count);



	return libbpf_err_errno(ret);

}

tools/lib/bpf/bpf.h

+78 −14
Original line number Diff line number Diff line
@@ -312,21 +312,67 @@ LIBBPF_API int bpf_obj_get(const char *pathname); 
LIBBPF_API int bpf_obj_get_opts(const char *pathname,

				const struct bpf_obj_get_opts *opts);



LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd,

			       enum bpf_attach_type type, unsigned int flags);

LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);

LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd,

				enum bpf_attach_type type);



struct bpf_prog_attach_opts {

	size_t sz; /* size of this struct for forward/backward compatibility */

	unsigned int flags;

	__u32 flags;

	union {

		int replace_prog_fd;

		int replace_fd;

	};

#define bpf_prog_attach_opts__last_field replace_prog_fd

	int relative_fd;

	__u32 relative_id;

	__u64 expected_revision;

	size_t :0;

};

#define bpf_prog_attach_opts__last_field expected_revision



LIBBPF_API int bpf_prog_attach(int prog_fd, int attachable_fd,

			       enum bpf_attach_type type, unsigned int flags);

LIBBPF_API int bpf_prog_attach_opts(int prog_fd, int attachable_fd,

struct bpf_prog_detach_opts {

	size_t sz; /* size of this struct for forward/backward compatibility */

	__u32 flags;

	int relative_fd;

	__u32 relative_id;

	__u64 expected_revision;

	size_t :0;

};

#define bpf_prog_detach_opts__last_field expected_revision



/**

 * @brief **bpf_prog_attach_opts()** attaches the BPF program corresponding to

 * *prog_fd* to a *target* which can represent a file descriptor or netdevice

 * ifindex.

 *

 * @param prog_fd BPF program file descriptor

 * @param target attach location file descriptor or ifindex

 * @param type attach type for the BPF program

 * @param opts options for configuring the attachment

 * @return 0, on success; negative error code, otherwise (errno is also set to

 * the error code)

 */

LIBBPF_API int bpf_prog_attach_opts(int prog_fd, int target,

				    enum bpf_attach_type type,

				    const struct bpf_prog_attach_opts *opts);

LIBBPF_API int bpf_prog_detach(int attachable_fd, enum bpf_attach_type type);

LIBBPF_API int bpf_prog_detach2(int prog_fd, int attachable_fd,

				enum bpf_attach_type type);



/**

 * @brief **bpf_prog_detach_opts()** detaches the BPF program corresponding to

 * *prog_fd* from a *target* which can represent a file descriptor or netdevice

 * ifindex.

 *

 * @param prog_fd BPF program file descriptor

 * @param target detach location file descriptor or ifindex

 * @param type detach type for the BPF program

 * @param opts options for configuring the detachment

 * @return 0, on success; negative error code, otherwise (errno is also set to

 * the error code)

 */

LIBBPF_API int bpf_prog_detach_opts(int prog_fd, int target,

				    enum bpf_attach_type type,

				    const struct bpf_prog_detach_opts *opts);



union bpf_iter_link_info; /* defined in up-to-date linux/bpf.h */

struct bpf_link_create_opts {
@@ -495,13 +541,31 @@ struct bpf_prog_query_opts { 
	__u32 query_flags;

	__u32 attach_flags; /* output argument */

	__u32 *prog_ids;

	__u32 prog_cnt; /* input+output argument */

	union {

		/* input+output argument */

		__u32 prog_cnt;

		__u32 count;

	};

	__u32 *prog_attach_flags;

	__u32 *link_ids;

	__u32 *link_attach_flags;

	__u64 revision;

	size_t :0;

};

#define bpf_prog_query_opts__last_field prog_attach_flags

#define bpf_prog_query_opts__last_field revision



LIBBPF_API int bpf_prog_query_opts(int target_fd,

				   enum bpf_attach_type type,

/**

 * @brief **bpf_prog_query_opts()** queries the BPF programs and BPF links

 * which are attached to *target* which can represent a file descriptor or

 * netdevice ifindex.

 *

 * @param target query location file descriptor or ifindex

 * @param type attach type for the BPF program

 * @param opts options for configuring the query

 * @return 0, on success; negative error code, otherwise (errno is also set to

 * the error code)

 */

LIBBPF_API int bpf_prog_query_opts(int target, enum bpf_attach_type type,

				   struct bpf_prog_query_opts *opts);

LIBBPF_API int bpf_prog_query(int target_fd, enum bpf_attach_type type,

			      __u32 query_flags, __u32 *attach_flags,

tools/lib/bpf/libbpf.c

+9 −3
Original line number Diff line number Diff line
@@ -118,6 +118,8 @@ static const char * const attach_type_name[] = { 
	[BPF_TRACE_KPROBE_MULTI]	= "trace_kprobe_multi",

	[BPF_STRUCT_OPS]		= "struct_ops",

	[BPF_NETFILTER]			= "netfilter",

	[BPF_TCX_INGRESS]		= "tcx_ingress",

	[BPF_TCX_EGRESS]		= "tcx_egress",

};



static const char * const link_type_name[] = {
@@ -8696,9 +8698,13 @@ static const struct bpf_sec_def section_defs[] = { 
	SEC_DEF("ksyscall+",		KPROBE,	0, SEC_NONE, attach_ksyscall),

	SEC_DEF("kretsyscall+",		KPROBE, 0, SEC_NONE, attach_ksyscall),

	SEC_DEF("usdt+",		KPROBE,	0, SEC_NONE, attach_usdt),

	SEC_DEF("tc",			SCHED_CLS, 0, SEC_NONE),

	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE),

	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE),

	SEC_DEF("tc/ingress",		SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE), /* alias for tcx */

	SEC_DEF("tc/egress",		SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE),  /* alias for tcx */

	SEC_DEF("tcx/ingress",		SCHED_CLS, BPF_TCX_INGRESS, SEC_NONE),

	SEC_DEF("tcx/egress",		SCHED_CLS, BPF_TCX_EGRESS, SEC_NONE),

	SEC_DEF("tc",			SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */

	SEC_DEF("classifier",		SCHED_CLS, 0, SEC_NONE), /* deprecated / legacy, use tcx */

	SEC_DEF("action",		SCHED_ACT, 0, SEC_NONE), /* deprecated / legacy, use tcx */

	SEC_DEF("tracepoint+",		TRACEPOINT, 0, SEC_NONE, attach_tp),

	SEC_DEF("tp+",			TRACEPOINT, 0, SEC_NONE, attach_tp),

	SEC_DEF("raw_tracepoint+",	RAW_TRACEPOINT, 0, SEC_NONE, attach_raw_tp),

tools/lib/bpf/libbpf.map

+1 −0
Original line number Diff line number Diff line
@@ -395,5 +395,6 @@ LIBBPF_1.2.0 { 
LIBBPF_1.3.0 {

	global:

		bpf_obj_pin_opts;

		bpf_prog_detach_opts;

		bpf_program__attach_netfilter;

} LIBBPF_1.2.0;