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 static int (*bpf_probe_read)(void *dst, int size, void *unsafe_ptr) =
  19         (void *) BPF_FUNC_probe_read;
  20 static unsigned long long (*bpf_ktime_get_ns)(void) =
  21         (void *) BPF_FUNC_ktime_get_ns;
  22 static int (*bpf_trace_printk)(const char *fmt, int fmt_size, ...) =
  23         (void *) BPF_FUNC_trace_printk;
  24
  25 /* llvm builtin functions that eBPF C program may use to
  26  * emit BPF_LD_ABS and BPF_LD_IND instructions
  27  */
  28 struct sk_buff;
  29 unsigned long long load_byte(void *skb,
  30                              unsigned long long off) asm("llvm.bpf.load.byte");
  31 unsigned long long load_half(void *skb,
  32                              unsigned long long off) asm("llvm.bpf.load.half");
  33 unsigned long long load_word(void *skb,
  34                              unsigned long long off) asm("llvm.bpf.load.word");
  35
  36 /* a helper structure used by eBPF C program
  37  * to describe map attributes to elf_bpf loader
  38  */
  39 struct bpf_map_def {
  40         unsigned int type;
  41         unsigned int key_size;
  42         unsigned int value_size;
  43         unsigned int max_entries;
  44 };
  45
  46 static int (*bpf_skb_store_bytes)(void *ctx, int off, void *from, int len, int flags) =
  47         (void *) BPF_FUNC_skb_store_bytes;
  48 static int (*bpf_l3_csum_replace)(void *ctx, int off, int from, int to, int flags) =
  49         (void *) BPF_FUNC_l3_csum_replace;
  50 static int (*bpf_l4_csum_replace)(void *ctx, int off, int from, int to, int flags) =
  51         (void *) BPF_FUNC_l4_csum_replace;
  52
  53 #endif