1 #include "../../include/bpf_api.h" 2 3 /* Minimal, stand-alone toy map pinning example: 4 * 5 * clang -target bpf -O2 [...] -o bpf_shared.o -c bpf_shared.c 6 * tc filter add dev foo parent 1: bpf obj bpf_shared.o sec egress 7 * tc filter add dev foo parent ffff: bpf obj bpf_shared.o sec ingress 8 * 9 * Both classifier will share the very same map instance in this example, 10 * so map content can be accessed from ingress *and* egress side! 11 * 12 * This example has a pinning of PIN_OBJECT_NS, so it's private and 13 * thus shared among various program sections within the object. 14 * 15 * A setting of PIN_GLOBAL_NS would place it into a global namespace, 16 * so that it can be shared among different object files. A setting 17 * of PIN_NONE (= 0) means no sharing, so each tc invocation a new map 18 * instance is being created. 19 */ 20 21 BPF_ARRAY4(map_sh, 0, PIN_OBJECT_NS, 1); /* or PIN_GLOBAL_NS, or PIN_NONE */ 22 23 __section("egress") 24 int emain(struct __sk_buff *skb) 25 { 26 int key = 0, *val; 27 28 val = map_lookup_elem(&map_sh, &key); 29 if (val) 30 lock_xadd(val, 1); 31 32 return BPF_H_DEFAULT; 33 } 34 35 __section("ingress") 36 int imain(struct __sk_buff *skb) 37 { 38 char fmt[] = "map val: %d\n"; 39 int key = 0, *val; 40 41 val = map_lookup_elem(&map_sh, &key); 42 if (val) 43 trace_printk(fmt, sizeof(fmt), *val); 44 45 return BPF_H_DEFAULT; 46 } 47 48 BPF_LICENSE("GPL"); 49
