From: Mykyta Yatsenko <yatsenko@xxxxxxxx>
Similarly to `bpf_program`, support `bpf_map` automatic attachment in
`bpf_object__attach_skeleton`. Currently only struct_ops maps could be
attached.
Bpftool
Code-generate links in skeleton struct for struct_ops maps.
Similarly to `bpf_program_skeleton`, set links in `bpf_map_skeleton`.
Libbpf
Extending `bpf_map` with new `autoattach` field to support enabling or
disabling autoattach functionality, introducing getter/setter for this
field.
Extending `bpf_object__(attach|detach)_skeleton` with
attaching/detaching struct_ops maps.
Signed-off-by: Mykyta Yatsenko <yatsenko@xxxxxxxx>
---
tools/bpf/bpftool/gen.c | 36 +++++++++++++++++++---
tools/lib/bpf/libbpf.c | 65 ++++++++++++++++++++++++++++++++++++++--
tools/lib/bpf/libbpf.h | 20 +++++++++++++
tools/lib/bpf/libbpf.map | 2 ++
4 files changed, 116 insertions(+), 7 deletions(-)
diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c
index b3979ddc0189..a8d4db0d8044 100644
--- a/tools/bpf/bpftool/gen.c
+++ b/tools/bpf/bpftool/gen.c
@@ -848,7 +848,7 @@ static int gen_trace(struct bpf_object *obj, const char *obj_name, const char *h
}
static void
-codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
+codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped, bool populate_links)
{
struct bpf_map *map;
char ident[256];
@@ -888,6 +888,14 @@ codegen_maps_skeleton(struct bpf_object *obj, size_t map_cnt, bool mmaped)
printf("\ts->maps[%zu].mmaped = (void **)&obj->%s;\n",
i, ident);
}
+
+ if (populate_links && bpf_map__type(map) == BPF_MAP_TYPE_STRUCT_OPS) {
+ codegen("\
+ \n\
+ s->maps[%zu].link = &obj->links.%s;\n\
+ ",
+ i, ident);
+ }
i++;
}
}
@@ -1141,7 +1149,7 @@ static void gen_st_ops_shadow_init(struct btf *btf, struct bpf_object *obj)
static int do_skeleton(int argc, char **argv)
{
char header_guard[MAX_OBJ_NAME_LEN + sizeof("__SKEL_H__")];
- size_t map_cnt = 0, prog_cnt = 0, file_sz, mmap_sz;
+ size_t map_cnt = 0, prog_cnt = 0, attach_map_cnt = 0, file_sz, mmap_sz;
DECLARE_LIBBPF_OPTS(bpf_object_open_opts, opts);
char obj_name[MAX_OBJ_NAME_LEN] = "", *obj_data;
struct bpf_object *obj = NULL;
@@ -1225,6 +1233,10 @@ static int do_skeleton(int argc, char **argv)
bpf_map__name(map));
continue;
}
+
+ if (bpf_map__type(map) == BPF_MAP_TYPE_STRUCT_OPS)
+ attach_map_cnt++;
+
map_cnt++;
}
bpf_object__for_each_program(prog, obj) {
@@ -1297,6 +1309,9 @@ static int do_skeleton(int argc, char **argv)
bpf_program__name(prog));
}
printf("\t} progs;\n");
+ }
+
+ if (prog_cnt + attach_map_cnt) {
printf("\tstruct {\n");
bpf_object__for_each_program(prog, obj) {
if (use_loader)
@@ -1306,6 +1321,19 @@ static int do_skeleton(int argc, char **argv)
printf("\t\tstruct bpf_link *%s;\n",
bpf_program__name(prog));
}
+
+ bpf_object__for_each_map(map, obj) {
+ if (!get_map_ident(map, ident, sizeof(ident)))
+ continue;
+ if (bpf_map__type(map) != BPF_MAP_TYPE_STRUCT_OPS)
+ continue;
+
+ if (use_loader)
+ printf("t\tint %s_fd;\n", ident);
+ else
+ printf("\t\tstruct bpf_link *%s;\n", ident);
+ }
+
printf("\t} links;\n");
}
@@ -1448,7 +1476,7 @@ static int do_skeleton(int argc, char **argv)
obj_name
);
- codegen_maps_skeleton(obj, map_cnt, true /*mmaped*/);
+ codegen_maps_skeleton(obj, map_cnt, true /*mmaped*/, true /*links*/);
codegen_progs_skeleton(obj, prog_cnt, true /*populate_links*/);
codegen("\
@@ -1786,7 +1814,7 @@ static int do_subskeleton(int argc, char **argv)
}
}
- codegen_maps_skeleton(obj, map_cnt, false /*mmaped*/);
+ codegen_maps_skeleton(obj, map_cnt, false /*mmaped*/, false /*links*/);
codegen_progs_skeleton(obj, prog_cnt, false /*links*/);
codegen("\
diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c
index d1627a2ca30b..ba9cb939c654 100644
--- a/tools/lib/bpf/libbpf.c
+++ b/tools/lib/bpf/libbpf.c
@@ -573,6 +573,7 @@ struct bpf_map {
bool reused;
bool autocreate;
__u64 map_extra;
+ bool autoattach;
};
enum extern_type {
@@ -1400,6 +1401,7 @@ static int init_struct_ops_maps(struct bpf_object *obj, const char *sec_name,
map->def.value_size = type->size;
map->def.max_entries = 1;
map->def.map_flags = strcmp(sec_name, STRUCT_OPS_LINK_SEC) == 0 ? BPF_F_LINK : 0;
+ map->autoattach = true;
map->st_ops = calloc(1, sizeof(*map->st_ops));
if (!map->st_ops)
@@ -4819,6 +4821,20 @@ int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate)
return 0;
}
+int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach)
+{
+ if (!bpf_map__is_struct_ops(map))
+ return libbpf_err(-EINVAL);
+
+ map->autoattach = autoattach;
+ return 0;
+}
+
+bool bpf_map__autoattach(const struct bpf_map *map)
+{
+ return map->autoattach;
+}
+
int bpf_map__reuse_fd(struct bpf_map *map, int fd)
{
struct bpf_map_info info;
@@ -12900,8 +12916,10 @@ struct bpf_link *bpf_map__attach_struct_ops(const struct bpf_map *map)
__u32 zero = 0;
int err, fd;
- if (!bpf_map__is_struct_ops(map))
+ if (!bpf_map__is_struct_ops(map)) {
+ pr_warn("map '%s': can't attach non-struct_ops map\n", map->name);
return libbpf_err_ptr(-EINVAL);
+ }
if (map->fd < 0) {
pr_warn("map '%s': can't attach BPF map without FD (was it created?)\n", map->name);
@@ -13945,6 +13963,36 @@ int bpf_object__attach_skeleton(struct bpf_object_skeleton *s)
*/
}
+ /* Skeleton is created with earlier version of bpftool
+ * which does not support auto-attachment
+ */
+ if (s->map_skel_sz < sizeof(struct bpf_map_skeleton))
+ return 0;
+
+ for (i = 0; i < s->map_cnt; i++) {
+ struct bpf_map *map = *s->maps[i].map;
+ struct bpf_link **link = s->maps[i].link;
+
+ if (!map->autocreate || !map->autoattach)
+ continue;
+
+ if (*link)
+ continue;
+
+ /* only struct_ops maps can be attached */
+ if (!bpf_map__is_struct_ops(map))
+ continue;
+ *link = bpf_map__attach_struct_ops(map);
+
+ if (!*link) {
+ const int errcode = errno;
+
+ pr_warn("struct_ops %s: failed to auto-attach: %d\n", bpf_map__name(map),
+ errcode);
+ return libbpf_err(-errcode);
+ }
+ }
+
return 0;
}
@@ -13958,6 +14006,18 @@ void bpf_object__detach_skeleton(struct bpf_object_skeleton *s)
bpf_link__destroy(*link);
*link = NULL;
}
+
+ if (s->map_skel_sz < sizeof(struct bpf_map_skeleton))
+ return;
+
+ for (i = 0; i < s->map_cnt; i++) {
+ struct bpf_link **link = s->maps[i].link;
+
+ if (link) {
+ bpf_link__destroy(*link);
+ *link = NULL;
+ }
+ }
}
void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
@@ -13965,8 +14025,7 @@ void bpf_object__destroy_skeleton(struct bpf_object_skeleton *s)
if (!s)
return;
- if (s->progs)
- bpf_object__detach_skeleton(s);
+ bpf_object__detach_skeleton(s);
if (s->obj)
bpf_object__close(*s->obj);
free(s->maps);
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 26e4e35528c5..641d6ec876e2 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -978,6 +978,25 @@ bpf_object__prev_map(const struct bpf_object *obj, const struct bpf_map *map);
LIBBPF_API int bpf_map__set_autocreate(struct bpf_map *map, bool autocreate);
LIBBPF_API bool bpf_map__autocreate(const struct bpf_map *map);
+/**
+ * @brief **bpf_map__set_autoattach()** sets whether libbpf has to auto-attach
+ * map during BPF skeleton attach phase.
+ * @param map the BPF map instance
+ * @param autoattach whether to attach map during BPF skeleton attach phase
+ * @return 0 on success; negative error code, otherwise
+ *
+ */
+LIBBPF_API int bpf_map__set_autoattach(struct bpf_map *map, bool autoattach);
+
+/**
+ * @brief **bpf_map__autoattach()** returns whether BPF map is configured to
+ * auto-attach during BPF skeleton attach phase.
+ * @param map the BPF map instance
+ * @return true if map is set to auto-attach during skeleton attach phase; false otherwise
+ *
+ */
+LIBBPF_API bool bpf_map__autoattach(const struct bpf_map *map);
+
/**
* @brief **bpf_map__fd()** gets the file descriptor of the passed
* BPF map
@@ -1672,6 +1691,7 @@ struct bpf_map_skeleton {
const char *name;
struct bpf_map **map;
void **mmaped;
+ struct bpf_link **link;
};
struct bpf_prog_skeleton {
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index c1ce8aa3520b..40595233dc7f 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -419,6 +419,8 @@ LIBBPF_1.4.0 {
LIBBPF_1.5.0 {
global:
+ bpf_map__autoattach;
+ bpf_map__set_autoattach;
bpf_program__attach_sockmap;
ring__consume_n;
ring_buffer__consume_n;
--
2.45.0
