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#include "../../include/bpf_api.h"
/* Minimal, stand-alone toy map pinning example:
*
* clang -target bpf -O2 [...] -o bpf_shared.o -c bpf_shared.c
* tc filter add dev foo parent 1: bpf obj bpf_shared.o sec egress
* tc filter add dev foo parent ffff: bpf obj bpf_shared.o sec ingress
*
* Both classifier will share the very same map instance in this example,
* so map content can be accessed from ingress *and* egress side!
*
* This example has a pinning of PIN_OBJECT_NS, so it's private and
* thus shared among various program sections within the object.
*
* A setting of PIN_GLOBAL_NS would place it into a global namespace,
* so that it can be shared among different object files. A setting
* of PIN_NONE (= 0) means no sharing, so each tc invocation a new map
* instance is being created.
*/
struct {
__uint(type, BPF_MAP_TYPE_ARRAY);
__uint(key_size, sizeof(uint32_t));
__uint(value_size, sizeof(uint32_t));
__uint(max_entries, 1);
__uint(pinning, LIBBPF_PIN_BY_NAME); /* or LIBBPF_PIN_NONE */
} map_sh __section(".maps");
__section("egress")
int emain(struct __sk_buff *skb)
{
int key = 0, *val;
val = map_lookup_elem(&map_sh, &key);
if (val)
lock_xadd(val, 1);
return BPF_H_DEFAULT;
}
__section("ingress")
int imain(struct __sk_buff *skb)
{
int key = 0, *val;
val = map_lookup_elem(&map_sh, &key);
if (val)
printt("map val: %d\n", *val);
return BPF_H_DEFAULT;
}
BPF_LICENSE("GPL");
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