samples/bpf/bpf_helpers.h

   1 #ifndef __BPF_HELPERS_H
   2 #define __BPF_HELPERS_H
   3
   4 /* helper macro to place programs, maps, license in
   5  * different sections in elf_bpf file. Section names
   6  * are interpreted by elf_bpf loader
   7  */
   8 #define SEC(NAME) __attribute__((section(NAME), used))
   9
  10 /* helper functions called from eBPF programs written in C */
  11 static void *(*bpf_map_lookup_elem)(void *map, void *key) =
  12         (void *) BPF_FUNC_map_lookup_elem;
  13 static int (*bpf_map_update_elem)(void *map, void *key, void *value,
  14                                   unsigned long long flags) =
  15         (void *) BPF_FUNC_map_update_elem;
  16 static int (*bpf_map_delete_elem)(void *map, void *key) =
  17         (void *) BPF_FUNC_map_delete_elem;
  18
  19 /* llvm builtin functions that eBPF C program may use to
  20  * emit BPF_LD_ABS and BPF_LD_IND instructions
  21  */
  22 struct sk_buff;
  23 unsigned long long load_byte(void *skb,
  24                              unsigned long long off) asm("llvm.bpf.load.byte");
  25 unsigned long long load_half(void *skb,
  26                              unsigned long long off) asm("llvm.bpf.load.half");
  27 unsigned long long load_word(void *skb,
  28                              unsigned long long off) asm("llvm.bpf.load.word");
  29
  30 /* a helper structure used by eBPF C program
  31  * to describe map attributes to elf_bpf loader
  32  */
  33 struct bpf_map_def {
  34         unsigned int type;
  35         unsigned int key_size;
  36         unsigned int value_size;
  37         unsigned int max_entries;
  38 };
  39
  40 #endif