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 struct bpf_elf_map __section_maps map_sh = { 22 .type = BPF_MAP_TYPE_ARRAY, 23 .size_key = sizeof(uint32_t), 24 .size_value = sizeof(uint32_t), 25 .pinning = PIN_OBJECT_NS, /* or PIN_GLOBAL_NS, or PIN_NONE */ 26 .max_elem = 1, 27 }; 28 29 __section("egress") 30 int emain(struct __sk_buff *skb) 31 { 32 int key = 0, *val; 33 34 val = map_lookup_elem(&map_sh, &key); 35 if (val) 36 lock_xadd(val, 1); 37 38 return BPF_H_DEFAULT; 39 } 40 41 __section("ingress") 42 int imain(struct __sk_buff *skb) 43 { 44 int key = 0, *val; 45 46 val = map_lookup_elem(&map_sh, &key); 47 if (val) 48 printt("map val: %d\n", *val); 49 50 return BPF_H_DEFAULT; 51 } 52 53 BPF_LICENSE("GPL"); 54
