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

   1 // SPDX-License-Identifier: GPL-2.0
   2 #include <linux/bpf.h>
   3 #include <bpf/bpf_helpers.h>
   4
   5 SEC("xdp_adjust_tail_grow")
   6 int _xdp_adjust_tail_grow(struct xdp_md *xdp)
   7 {
   8         void *data_end = (void *)(long)xdp->data_end;
   9         void *data = (void *)(long)xdp->data;
  10         unsigned int data_len;
  11         int offset = 0;
  12
  13         /* Data length determine test case */
  14         data_len = data_end - data;
  15
  16         if (data_len == 54) { /* sizeof(pkt_v4) */
  17                 offset = 4096; /* test too large offset */
  18         } else if (data_len == 74) { /* sizeof(pkt_v6) */
  19                 offset = 40;
  20         } else if (data_len == 64) {
  21                 offset = 128;
  22         } else if (data_len == 128) {
  23                 offset = 4096 - 256 - 320 - data_len; /* Max tail grow 3520 */
  24         } else {
  25                 return XDP_ABORTED; /* No matching test */
  26         }
  27
  28         if (bpf_xdp_adjust_tail(xdp, offset))
  29                 return XDP_DROP;
  30         return XDP_TX;
  31 }
  32
  33 char _license[] SEC("license") = "GPL";