Libbpf eBPF macro __array

v0.0.9

The __array macros is used to define array properties of BTF maps.

Definition

#define __array(name, val) typeof(val) *name[]

Usage

This macro is used to encode array properties in BTF map definitions. This is useful when defining maps of maps or tail call maps in eBPF programs.

Example

struct inner_map {
        __uint(type, BPF_MAP_TYPE_ARRAY);
        __uint(max_entries, 1);
        __type(key, int);
        __type(value, int);
} inner_map1 SEC(".maps"),
inner_map2 SEC(".maps");

struct outer_hash {
        __uint(type, BPF_MAP_TYPE_HASH_OF_MAPS);
        __uint(max_entries, 5);
        __uint(key_size, sizeof(int));
        __array(values, struct inner_map);
} outer_hash SEC(".maps") = {
        .values = {
                [0] = &inner_map2,
                [4] = &inner_map1,
        },
};