iproute2/examples/bpf/bpf_map_in_map.c
Hangbin Liu 71c7c1fb4f examples/bpf: add bpf examples with BTF defined maps
Users should try use the new BTF defined maps instead of struct
bpf_elf_map defined maps. The tail call examples are not added yet
as libbpf doesn't currently support declaratively populating tail call
maps.

Reviewed-by: Toke Høiland-Jørgensen <toke@redhat.com>
Signed-off-by: Hangbin Liu <haliu@redhat.com>
Signed-off-by: David Ahern <dsahern@gmail.com>
2020-11-24 22:14:08 -07:00

56 lines
1.1 KiB
C

#include "../../include/bpf_api.h"
struct inner_map {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(key_size, sizeof(uint32_t));
__uint(value_size, sizeof(uint32_t));
__uint(max_entries, 1);
} map_inner __section(".maps");
struct {
__uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS);
__uint(key_size, sizeof(uint32_t));
__uint(value_size, sizeof(uint32_t));
__uint(max_entries, 1);
__uint(pinning, LIBBPF_PIN_BY_NAME);
__array(values, struct inner_map);
} map_outer __section(".maps") = {
.values = {
[0] = &map_inner,
},
};
__section("egress")
int emain(struct __sk_buff *skb)
{
struct bpf_elf_map *map_inner;
int key = 0, *val;
map_inner = map_lookup_elem(&map_outer, &key);
if (map_inner) {
val = map_lookup_elem(map_inner, &key);
if (val)
lock_xadd(val, 1);
}
return BPF_H_DEFAULT;
}
__section("ingress")
int imain(struct __sk_buff *skb)
{
struct bpf_elf_map *map_inner;
int key = 0, *val;
map_inner = map_lookup_elem(&map_outer, &key);
if (map_inner) {
val = map_lookup_elem(map_inner, &key);
if (val)
printt("map val: %d\n", *val);
}
return BPF_H_DEFAULT;
}
BPF_LICENSE("GPL");