[PATCH bpf-next v5 4/7] libbpf: Add support for associating BPF program with struct_ops

Amery Hung
2025-11-04T17:27:00Z

Add low-level wrapper and libbpf API for BPF_PROG_ASSOC_STRUCT_OPS
command in the bpf() syscall.

Signed-off-by: Amery Hung <ameryhung@gmail.com>
---
tools/lib/bpf/bpf.c | 19 +++++++++++++++++++
tools/lib/bpf/bpf.h | 21 +++++++++++++++++++++
tools/lib/bpf/libbpf.c | 30 ++++++++++++++++++++++++++++++
tools/lib/bpf/libbpf.h | 16 ++++++++++++++++
tools/lib/bpf/libbpf.map | 2 ++
5 files changed, 88 insertions(+)

diff --git a/tools/lib/bpf/bpf.c b/tools/lib/bpf/bpf.c
index b66f5fbfbbb2..21b57a629916 100644
--- a/tools/lib/bpf/bpf.c
+++ b/tools/lib/bpf/bpf.c
@@ -1397,3 +1397,22 @@ int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len,
err = sys_bpf(BPF_PROG_STREAM_READ_BY_FD, &attr, attr_sz);
return libbpf_err_errno(err);
}
+
+int bpf_prog_assoc_struct_ops(int prog_fd, int map_fd,
+ struct bpf_prog_assoc_struct_ops_opts *opts)
+{
+ const size_t attr_sz = offsetofend(union bpf_attr, prog_assoc_struct_ops);
+ union bpf_attr attr;
+ int err;
+
+ if (!OPTS_VALID(opts, bpf_prog_assoc_struct_ops_opts))
+ return libbpf_err(-EINVAL);
+
+ memset(&attr, 0, attr_sz);
+ attr.prog_assoc_struct_ops.map_fd = map_fd;
+ attr.prog_assoc_struct_ops.prog_fd = prog_fd;
+ attr.prog_assoc_struct_ops.flags = OPTS_GET(opts, flags, 0);
+
+ err = sys_bpf(BPF_PROG_ASSOC_STRUCT_OPS, &attr, attr_sz);
+ return libbpf_err_errno(err);
+}
diff --git a/tools/lib/bpf/bpf.h b/tools/lib/bpf/bpf.h
index e983a3e40d61..1f9c28d27795 100644
--- a/tools/lib/bpf/bpf.h
+++ b/tools/lib/bpf/bpf.h
@@ -733,6 +733,27 @@ struct bpf_prog_stream_read_opts {
LIBBPF_API int bpf_prog_stream_read(int prog_fd, __u32 stream_id, void *buf, __u32 buf_len,
struct bpf_prog_stream_read_opts *opts);

+struct bpf_prog_assoc_struct_ops_opts {
+ size_t sz;
+ __u32 flags;
+ size_t :0;
+};
+#define bpf_prog_assoc_struct_ops_opts__last_field flags
+
+/**
+ * @brief **bpf_prog_assoc_struct_ops** associates a BPF program with a
+ * struct_ops map.
+ *
+ * @param prog_fd FD for the BPF program
+ * @param map_fd FD for the struct_ops map to be associated with the BPF program
+ * @param opts optional options, can be NULL
+ *
+ * @return 0 on success; negative error code, otherwise (errno is also set to
+ * the error code)
+ */
+LIBBPF_API int bpf_prog_assoc_struct_ops(int prog_fd, int map_fd,
+ struct bpf_prog_assoc_struct_ops_opts *opts);
+
#ifdef __cplusplus
} /* extern "C" */
#endif
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index fbe74686c97d..260e1feaa665 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -13891,6 +13891,36 @@ int bpf_program__set_attach_target(struct bpf_program *prog,
return 0;
}

+int bpf_program__assoc_struct_ops(struct bpf_program *prog, struct bpf_map *map,
+ struct bpf_prog_assoc_struct_ops_opts *opts)
+{
+ int prog_fd;
+
+ prog_fd = bpf_program__fd(prog);
+ if (prog_fd < 0) {
+ pr_warn("prog '%s': can't associate BPF program without FD (was it loaded?)\n",
+ prog->name);
+ return -EINVAL;
+ }
+
+ if (prog->type == BPF_PROG_TYPE_STRUCT_OPS) {
+ pr_warn("prog '%s': can't associate struct_ops program\n", prog->name);
+ return -EINVAL;
+ }
+
+ if (map->fd < 0) {
+ pr_warn("map '%s': can't associate BPF map without FD (was it created?)\n", map->name);
+ return -EINVAL;
+ }
+
+ if (!bpf_map__is_struct_ops(map)) {
+ pr_warn("map '%s': can't associate non-struct_ops map\n", map->name);
+ return -EINVAL;
+ }
+
+ return bpf_prog_assoc_struct_ops(prog_fd, map->fd, opts);
+}
+
int parse_cpu_mask_str(const char *s, bool **mask, int *mask_sz)
{
int err = 0, n, len, start, end = -1;
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 5118d0a90e24..45720b7c2aaa 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1003,6 +1003,22 @@ LIBBPF_API int
bpf_program__set_attach_target(struct bpf_program *prog, int attach_prog_fd,
const char *attach_func_name);

+struct bpf_prog_assoc_struct_ops_opts; /* defined in bpf.h */
+
+/**
+ * @brief **bpf_program__assoc_struct_ops()** associates a BPF program with a
+ * struct_ops map.
+ *
+ * @param prog BPF program
+ * @param map struct_ops map to be associated with the BPF program
+ * @param opts optional options, can be NULL
+ *
+ * @return error code; or 0 if no error occurred.
+ */
+LIBBPF_API int
+bpf_program__assoc_struct_ops(struct bpf_program *prog, struct bpf_map *map,
+ struct bpf_prog_assoc_struct_ops_opts *opts);
+
/**
* @brief **bpf_object__find_map_by_name()** returns BPF map of
* the given name, if it exists within the passed BPF object
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 8ed8749907d4..84fb90a016c9 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -451,4 +451,6 @@ LIBBPF_1.7.0 {
global:
bpf_map__set_exclusive_program;
bpf_map__exclusive_program;
+ bpf_prog_assoc_struct_ops;
+ bpf_program__assoc_struct_ops;
} LIBBPF_1.6.0;
--
2.47.3