samples/bpf/sockex1_kern.c

   1 #include <uapi/linux/bpf.h>
   2 #include <uapi/linux/if_ether.h>
   3 #include <uapi/linux/ip.h>
   4 #include "bpf_helpers.h"
   5
   6 struct bpf_map_def SEC("maps") my_map = {
   7         .type = BPF_MAP_TYPE_ARRAY,
   8         .key_size = sizeof(u32),
   9         .value_size = sizeof(long),
  10         .max_entries = 256,
  11 };
  12
  13 SEC("socket1")
  14 int bpf_prog1(struct sk_buff *skb)
  15 {
  16         int index = load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol));
  17         long *value;
  18
  19         value = bpf_map_lookup_elem(&my_map, &index);
  20         if (value)
  21                 __sync_fetch_and_add(value, 1);
  22
  23         return 0;
  24 }
  25 char _license[] SEC("license") = "GPL";