tools/testing/selftests/bpf/test_pkt_md_access.c

   1 /* Copyright (c) 2017 Facebook
   2  *
   3  * This program is free software; you can redistribute it and/or
   4  * modify it under the terms of version 2 of the GNU General Public
   5  * License as published by the Free Software Foundation.
   6  */
   7 #include <stddef.h>
   8 #include <string.h>
   9 #include <linux/bpf.h>
  10 #include <linux/pkt_cls.h>
  11 #include "bpf_helpers.h"
  12
  13 int _version SEC("version") = 1;
  14
  15 #if  __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
  16 #define TEST_FIELD(TYPE, FIELD, MASK)                                   \
  17         {                                                               \
  18                 TYPE tmp = *(volatile TYPE *)&skb->FIELD;               \
  19                 if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
  20                         return TC_ACT_SHOT;                             \
  21         }
  22 #else
  23 #define TEST_FIELD_OFFSET(a, b) ((sizeof(a) - sizeof(b)) / sizeof(b))
  24 #define TEST_FIELD(TYPE, FIELD, MASK)                                   \
  25         {                                                               \
  26                 TYPE tmp = *((volatile TYPE *)&skb->FIELD +             \
  27                               TEST_FIELD_OFFSET(skb->FIELD, TYPE));     \
  28                 if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
  29                         return TC_ACT_SHOT;                             \
  30         }
  31 #endif
  32
  33 SEC("test1")
  34 int process(struct __sk_buff *skb)
  35 {
  36         TEST_FIELD(__u8,  len, 0xFF);
  37         TEST_FIELD(__u16, len, 0xFFFF);
  38         TEST_FIELD(__u32, len, 0xFFFFFFFF);
  39         TEST_FIELD(__u16, protocol, 0xFFFF);
  40         TEST_FIELD(__u32, protocol, 0xFFFFFFFF);
  41         TEST_FIELD(__u8,  hash, 0xFF);
  42         TEST_FIELD(__u16, hash, 0xFFFF);
  43         TEST_FIELD(__u32, hash, 0xFFFFFFFF);
  44
  45         return TC_ACT_OK;
  46 }