bpf: adding support for mapinmap in libbpf

PATCH Applied Nikita V. Shirokov 2 participants 4 messages Nov 21, 2018 – Nov 22, 2018

Subsystems (6)

Networking Network drivers Kselftest BPF +2 more subsystems

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Nikita V. Shirokov

author

2018-11-21 15:28 UTC #0 lore raw

v5 cover bpf: adding support for mapinmap in libbpf

in this patch series i'm adding a helper for libbpf which would allow it to load map-in-map(BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS).
first patch contains new helper + explains proposed workflow second patch contains tests which also could be used as example of usage

v4->v5:
- naming: renamed everything to map_in_map instead of mapinmap
- start to return nonzero val if set_inner_map_fd failed

v3->v4:
- renamed helper to set_inner_map_fd
- now we set this value only if it haven't been set before and only for (array|hash) of maps

v2->v3:
- fixing typo in patch description
- initializing inner_map_fd to -1 by default

v1->v2:
- addressing nits
- removing const identifier from fd in new helper
- starting to check return val for bpf_map_update_elem

Nikita V. Shirokov (2):
bpf: adding support for map in map in libbpf
bpf: adding tests for mapinmap helpber in libbpf

 tools/lib/bpf/libbpf.c                        | 40 ++++++++++--
 tools/lib/bpf/libbpf.h                        |  2 +
 tools/testing/selftests/bpf/Makefile          |  3 +-
 tools/testing/selftests/bpf/test_map_in_map.c | 49 +++++++++++++++
 tools/testing/selftests/bpf/test_maps.c       | 90 +++++++++++++++++++++++++++
 5 files changed, 177 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/test_map_in_map.c

Signature · 1 line

2.15.1

Nikita V. Shirokov

author

2018-11-21 15:28 UTC #1 lore raw

PATCH v5 1/2 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 <[email protected]>

Acked-by Yonghong Song <[email protected]>

---
 tools/lib/bpf/libbpf.c | 40 ++++++++++++++++++++++++++++++++++------
 tools/lib/bpf/libbpf.h |  2 ++
 2 files changed, 36 insertions(+), 6 deletions(-)

tools/lib/bpf/libbpf.c +34 -6

index cb6565d79603..ba12e070f182 100644
@@ -167,6 +167,7 @@ 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;

@@ -594,6 +595,14 @@ 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)
 {

@@ -657,13 +666,15 @@ 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.

@@ -1164,6 +1175,9 @@ 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);

@@ -2621,6 +2635,20 @@ 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)
 {

tools/lib/bpf/libbpf.h +2 -0

index b1686a787102..16158b6b213f 100644
@@ -293,6 +293,8 @@ 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 {

Signature · 1 line

2.15.1

Nikita V. Shirokov

author

2018-11-21 15:28 UTC #2 lore raw

PATCH v5 2/2 bpf: adding tests for map_in_map helpber in libbpf

In reply to Nikita V. Shirokov

adding test/example of bpf_map__set_inner_map_fd usage

Signed-off-by Nikita V. Shirokov <[email protected]>

Acked-by Yonghong Song <[email protected]>

---
 tools/testing/selftests/bpf/Makefile          |  3 +-
 tools/testing/selftests/bpf/test_map_in_map.c | 49 +++++++++++++++
 tools/testing/selftests/bpf/test_maps.c       | 90 +++++++++++++++++++++++++++
 3 files changed, 141 insertions(+), 1 deletion(-)
 create mode 100644 tools/testing/selftests/bpf/test_map_in_map.c

tools/testing/selftests/bpf/Makefile +2 -1

index 1dde03ea1484..43157bd89165 100644
@@ -38,7 +38,8 @@ TEST_GEN_FILES = test_pkt_access.o test_xdp.o test_l4lb.o test_tcp_estats.o test
 	test_lwt_seg6local.o sendmsg4_prog.o sendmsg6_prog.o test_lirc_mode2_kern.o \
 	get_cgroup_id_kern.o socket_cookie_prog.o test_select_reuseport_kern.o \
 	test_skb_cgroup_id_kern.o bpf_flow.o netcnt_prog.o \
-	test_sk_lookup_kern.o test_xdp_vlan.o test_queue_map.o test_stack_map.o
+	test_sk_lookup_kern.o test_xdp_vlan.o test_queue_map.o test_stack_map.o \
+	test_map_in_map.o
 
 # Order correspond to 'make run_tests' order
 TEST_PROGS := test_kmod.sh \

tools/testing/selftests/bpf/test_map_in_map.c new file +49 -0

49 lines not on this page · raw message

tools/testing/selftests/bpf/test_maps.c +90 -0

102 lines not on this page · raw message

Signature · 1 line

2.15.1

Daniel Borkmann

maintainer Applied

2018-11-22 09:14 UTC #3 lore raw

In reply to Nikita V. Shirokov

Quoted 28 lines · Nikita V. Shirokov

in this patch series i'm adding a helper for libbpf which would allow it to load map-in-map(BPF_MAP_TYPE_ARRAY_OF_MAPS and BPF_MAP_TYPE_HASH_OF_MAPS).
first patch contains new helper + explains proposed workflow second patch contains tests which also could be used as example of usage
v4->v5:
- naming: renamed everything to map_in_map instead of mapinmap
- start to return nonzero val if set_inner_map_fd failed
v3->v4:
- renamed helper to set_inner_map_fd
- now we set this value only if it haven't been set before and only for (array|hash) of maps
v2->v3:
- fixing typo in patch description
- initializing inner_map_fd to -1 by default
v1->v2:
- addressing nits
- removing const identifier from fd in new helper
- starting to check return val for bpf_map_update_elem
Nikita V. Shirokov (2):
bpf: adding support for map in map in libbpf
bpf: adding tests for mapinmap helpber in libbpf

Quoted 8 lines

 tools/lib/bpf/libbpf.c                        | 40 ++++++++++--
 tools/lib/bpf/libbpf.h                        |  2 +
 tools/testing/selftests/bpf/Makefile          |  3 +-
 tools/testing/selftests/bpf/test_map_in_map.c | 49 +++++++++++++++
 tools/testing/selftests/bpf/test_maps.c       | 90 +++++++++++++++++++++++++++
 5 files changed, 177 insertions(+), 7 deletions(-)
 create mode 100644 tools/testing/selftests/bpf/test_map_in_map.c

Applied, thanks!