tools/testing/selftests/bpf/progs/test_xdp_meta.c

   1 #include <linux/bpf.h>
   2 #include <linux/if_ether.h>
   3 #include <linux/pkt_cls.h>
   4
   5 #include "bpf_helpers.h"
   6
   7 #define __round_mask(x, y) ((__typeof__(x))((y) - 1))
   8 #define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1)
   9 #define ctx_ptr(ctx, mem) (void *)(unsigned long)ctx->mem
  10
  11 SEC("t")
  12 int ing_cls(struct __sk_buff *ctx)
  13 {
  14         __u8 *data, *data_meta, *data_end;
  15         __u32 diff = 0;
  16
  17         data_meta = ctx_ptr(ctx, data_meta);
  18         data_end  = ctx_ptr(ctx, data_end);
  19         data      = ctx_ptr(ctx, data);
  20
  21         if (data + ETH_ALEN > data_end ||
  22             data_meta + round_up(ETH_ALEN, 4) > data)
  23                 return TC_ACT_SHOT;
  24
  25         diff |= ((__u32 *)data_meta)[0] ^ ((__u32 *)data)[0];
  26         diff |= ((__u16 *)data_meta)[2] ^ ((__u16 *)data)[2];
  27
  28         return diff ? TC_ACT_SHOT : TC_ACT_OK;
  29 }
  30
  31 SEC("x")
  32 int ing_xdp(struct xdp_md *ctx)
  33 {
  34         __u8 *data, *data_meta, *data_end;
  35         int ret;
  36
  37         ret = bpf_xdp_adjust_meta(ctx, -round_up(ETH_ALEN, 4));
  38         if (ret < 0)
  39                 return XDP_DROP;
  40
  41         data_meta = ctx_ptr(ctx, data_meta);
  42         data_end  = ctx_ptr(ctx, data_end);
  43         data      = ctx_ptr(ctx, data);
  44
  45         if (data + ETH_ALEN > data_end ||
  46             data_meta + round_up(ETH_ALEN, 4) > data)
  47                 return XDP_DROP;
  48
  49         __builtin_memcpy(data_meta, data, ETH_ALEN);
  50         return XDP_PASS;
  51 }
  52
  53 char _license[] SEC("license") = "GPL";