// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2017 Facebook
 */
#include <stddef.h>
#include <string.h>
#include <linux/bpf.h>
#include <linux/pkt_cls.h>
#include <bpf/bpf_helpers.h>

#if  __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
#define TEST_FIELD(TYPE, FIELD, MASK)                                   \
        {                                                               \
                TYPE tmp = *(volatile TYPE *)&skb->FIELD;               \
                if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
                        return TC_ACT_SHOT;                             \
        }
#else
#define TEST_FIELD_OFFSET(a, b) ((sizeof(a) - sizeof(b)) / sizeof(b))
#define TEST_FIELD(TYPE, FIELD, MASK)                                   \
        {                                                               \
                TYPE tmp = *((volatile TYPE *)&skb->FIELD +             \
                              TEST_FIELD_OFFSET(skb->FIELD, TYPE));     \
                if (tmp != ((*(volatile __u32 *)&skb->FIELD) & MASK))   \
                        return TC_ACT_SHOT;                             \
        }
#endif

SEC("tc")
int test_pkt_md_access(struct __sk_buff *skb)
{
        TEST_FIELD(__u8,  len, 0xFF);
        TEST_FIELD(__u16, len, 0xFFFF);
        TEST_FIELD(__u32, len, 0xFFFFFFFF);
        TEST_FIELD(__u16, protocol, 0xFFFF);
        TEST_FIELD(__u32, protocol, 0xFFFFFFFF);
        TEST_FIELD(__u8,  hash, 0xFF);
        TEST_FIELD(__u16, hash, 0xFFFF);
        TEST_FIELD(__u32, hash, 0xFFFFFFFF);

        return TC_ACT_OK;
}