LXR linux/tools/testing/selftests/bpf/progs/load_bytes

   1// SPDX-License-Identifier: GPL-2.0-only
   2
   3/*
   4 * Copyright 2020 Google LLC.
   5 */
   6
   7#include <errno.h>
   8#include <linux/bpf.h>
   9#include <linux/if_ether.h>
  10#include <linux/ip.h>
  11#include <bpf/bpf_helpers.h>
  12
  13struct {
  14        __uint(type, BPF_MAP_TYPE_ARRAY);
  15        __uint(max_entries, 1);
  16        __type(key, __u32);
  17        __type(value, __u32);
  18} test_result SEC(".maps");
  19
  20SEC("cgroup_skb/egress")
  21int load_bytes_relative(struct __sk_buff *skb)
  22{
  23        struct ethhdr eth;
  24        struct iphdr iph;
  25
  26        __u32 map_key = 0;
  27        __u32 test_passed = 0;
  28
  29        /* MAC header is not set by the time cgroup_skb/egress triggers */
  30        if (bpf_skb_load_bytes_relative(skb, 0, &eth, sizeof(eth),
  31                                        BPF_HDR_START_MAC) != -EFAULT)
  32                goto fail;
  33
  34        if (bpf_skb_load_bytes_relative(skb, 0, &iph, sizeof(iph),
  35                                        BPF_HDR_START_NET))
  36                goto fail;
  37
  38        if (bpf_skb_load_bytes_relative(skb, 0xffff, &iph, sizeof(iph),
  39                                        BPF_HDR_START_NET) != -EFAULT)
  40                goto fail;
  41
  42        test_passed = 1;
  43
  44fail:
  45        bpf_map_update_elem(&test_result, &map_key, &test_passed, BPF_ANY);
  46
  47        return 1;
  48}
  49