From addb9fc90f13898e7779da54f471792e3dfb0d55 Mon Sep 17 00:00:00 2001 From: "Nikita V. Shirokov" Date: Tue, 20 Nov 2018 20:55:56 -0800 Subject: [PATCH] bpf: adding support for map in map in libbpf idea is pretty simple. for specified map (pointed by struct bpf_map) we would provide descriptor of already loaded map, which is going to be used as a prototype for inner map. proposed workflow: 1) open bpf's object (bpf_object__open) 2) create bpf's map which is going to be used as a prototype 3) find (by name) map-in-map which you want to load and update w/ descriptor of inner map w/ a new helper from this patch 4) load bpf program w/ bpf_object__load Signed-off-by: Nikita V. Shirokov Acked-by: Yonghong Song Signed-off-by: Daniel Borkmann --- tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++------ tools/lib/bpf/libbpf.h | 2 ++ 2 files changed, 36 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index edbae2b1b046..0f14f7c074c2 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -175,6 +175,7 @@ struct bpf_map { char *name; size_t offset; int map_ifindex; + int inner_map_fd; struct bpf_map_def def; __u32 btf_key_type_id; __u32 btf_value_type_id; @@ -605,6 +606,14 @@ static int compare_bpf_map(const void *_a, const void *_b) return a->offset - b->offset; } +static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) +{ + if (type == BPF_MAP_TYPE_ARRAY_OF_MAPS || + type == BPF_MAP_TYPE_HASH_OF_MAPS) + return true; + return false; +} + static int bpf_object__init_maps(struct bpf_object *obj, int flags) { @@ -668,13 +677,15 @@ bpf_object__init_maps(struct bpf_object *obj, int flags) } obj->nr_maps = nr_maps; - /* - * fill all fd with -1 so won't close incorrect - * fd (fd=0 is stdin) when failure (zclose won't close - * negative fd)). - */ - for (i = 0; i < nr_maps; i++) + for (i = 0; i < nr_maps; i++) { + /* + * fill all fd with -1 so won't close incorrect + * fd (fd=0 is stdin) when failure (zclose won't close + * negative fd)). + */ obj->maps[i].fd = -1; + obj->maps[i].inner_map_fd = -1; + } /* * Fill obj->maps using data in "maps" section. @@ -1222,6 +1233,9 @@ bpf_object__create_maps(struct bpf_object *obj) create_attr.btf_fd = 0; create_attr.btf_key_type_id = 0; create_attr.btf_value_type_id = 0; + if (bpf_map_type__is_map_in_map(def->type) && + map->inner_map_fd >= 0) + create_attr.inner_map_fd = map->inner_map_fd; if (obj->btf && !bpf_map_find_btf_info(map, obj->btf)) { create_attr.btf_fd = btf__fd(obj->btf); @@ -2681,6 +2695,20 @@ void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex) map->map_ifindex = ifindex; } +int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd) +{ + if (!bpf_map_type__is_map_in_map(map->def.type)) { + pr_warning("error: unsupported map type\n"); + return -EINVAL; + } + if (map->inner_map_fd != -1) { + pr_warning("error: inner_map_fd already specified\n"); + return -EINVAL; + } + map->inner_map_fd = fd; + return 0; +} + static struct bpf_map * __bpf_map__iter(struct bpf_map *m, struct bpf_object *obj, int i) { diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h index 74e57e041705..f30c3d07bb7d 100644 --- a/tools/lib/bpf/libbpf.h +++ b/tools/lib/bpf/libbpf.h @@ -297,6 +297,8 @@ LIBBPF_API void bpf_map__set_ifindex(struct bpf_map *map, __u32 ifindex); LIBBPF_API int bpf_map__pin(struct bpf_map *map, const char *path); LIBBPF_API int bpf_map__unpin(struct bpf_map *map, const char *path); +LIBBPF_API int bpf_map__set_inner_map_fd(struct bpf_map *map, int fd); + LIBBPF_API long libbpf_get_error(const void *ptr); struct bpf_prog_load_attr {