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

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* Copyright (c) 2017 Facebook
   3  */
   4 #include <stddef.h>
   5 #include <string.h>
   6 #include <linux/bpf.h>
   7 #include <linux/pkt_cls.h>
   8 #include <bpf/bpf_helpers.h>
   9
  10 #if  __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  11 #define TEST_FIELD(TYPE, FIELD, MASK)                                   \
  12         {                                                               \
  13                 TYPE tmp = *(volatile TYPE *)&skb->FIELD;               \
  14                 if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
  15                         return TC_ACT_SHOT;                             \
  16         }
  17 #else
  18 #define TEST_FIELD_OFFSET(a, b) ((sizeof(a) - sizeof(b)) / sizeof(b))
  19 #define TEST_FIELD(TYPE, FIELD, MASK)                                   \
  20         {                                                               \
  21                 TYPE tmp = *((volatile TYPE *)&skb->FIELD +             \
  22                               TEST_FIELD_OFFSET(skb->FIELD, TYPE));     \
  23                 if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
  24                         return TC_ACT_SHOT;                             \
  25         }
  26 #endif
  27
  28 SEC("tc")
  29 int test_pkt_md_access(struct __sk_buff *skb)
  30 {
  31         TEST_FIELD(__u8,  len, 0xFF);
  32         TEST_FIELD(__u16, len, 0xFFFF);
  33         TEST_FIELD(__u32, len, 0xFFFFFFFF);
  34         TEST_FIELD(__u16, protocol, 0xFFFF);
  35         TEST_FIELD(__u32, protocol, 0xFFFFFFFF);
  36         TEST_FIELD(__u8,  hash, 0xFF);
  37         TEST_FIELD(__u16, hash, 0xFFFF);
  38         TEST_FIELD(__u32, hash, 0xFFFFFFFF);
  39
  40         return TC_ACT_OK;
  41 }