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

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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: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20230719140858.13224-4-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann
2023-07-19 16:08:53 +02:00
committed by Andrii Nakryiko
parent b064c40d94
commit bb5d7c1be8
4 changed files with 159 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

107
src/bpf.c
View File

@@ -629,55 +629,89 @@ 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,
const struct bpf_prog_attach_opts *opts)
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.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.target_fd = target;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
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;
if (!OPTS_VALID(opts, bpf_prog_detach_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.attach_type = type;
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)
{
const size_t attr_sz = offsetofend(union bpf_attr, replace_bpf_fd);
union bpf_attr attr;
int ret;
memset(&attr, 0, attr_sz);
attr.target_fd = target_fd;
attr.attach_bpf_fd = prog_fd;
attr.attach_type = type;
ret = sys_bpf(BPF_PROG_DETACH, &attr, attr_sz);
return libbpf_err_errno(ret);
return bpf_prog_detach_opts(prog_fd, target_fd, type, NULL);
}
int bpf_link_create(int prog_fd, int target_fd,
@@ -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.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.prog_ids = ptr_to_u64(OPTS_GET(opts, prog_ids, NULL));
attr.query.prog_attach_flags = ptr_to_u64(OPTS_GET(opts, prog_attach_flags, NULL));
attr.query.target_fd = target;
attr.query.attach_type = type;
attr.query.query_flags = OPTS_GET(opts, query_flags, 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);
}

92
src/bpf.h
View File

@@ -312,22 +312,68 @@ 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);
struct bpf_prog_attach_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
unsigned int flags;
int replace_prog_fd;
};
#define bpf_prog_attach_opts__last_field replace_prog_fd
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,
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);
struct bpf_prog_attach_opts {
size_t sz; /* size of this struct for forward/backward compatibility */
__u32 flags;
union {
int replace_prog_fd;
int replace_fd;
};
int relative_fd;
__u32 relative_id;
__u64 expected_revision;
size_t :0;
};
#define bpf_prog_attach_opts__last_field expected_revision
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);
/**
* @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 {
size_t sz; /* size of this struct for forward/backward compatibility */
@@ -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,

12
src/libbpf.c
View File

@@ -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),

1
src/libbpf.map
View File

@@ -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;