cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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test_xdp_update_frags.c (1000B)

      1// SPDX-License-Identifier: GPL-2.0
      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 <linux/bpf.h>
      8#include <linux/if_ether.h>
      9#include <bpf/bpf_helpers.h>
     10
     11int _version SEC("version") = 1;
     12
     13SEC("xdp.frags")
     14int xdp_adjust_frags(struct xdp_md *xdp)
     15{
     16	__u8 *data_end = (void *)(long)xdp->data_end;
     17	__u8 *data = (void *)(long)xdp->data;
     18	__u8 val[16] = {};
     19	__u32 offset;
     20	int err;
     21
     22	if (data + sizeof(__u32) > data_end)
     23		return XDP_DROP;
     24
     25	offset = *(__u32 *)data;
     26	err = bpf_xdp_load_bytes(xdp, offset, val, sizeof(val));
     27	if (err < 0)
     28		return XDP_DROP;
     29
     30	if (val[0] != 0xaa || val[15] != 0xaa) /* marker */
     31		return XDP_DROP;
     32
     33	val[0] = 0xbb; /* update the marker */
     34	val[15] = 0xbb;
     35	err = bpf_xdp_store_bytes(xdp, offset, val, sizeof(val));
     36	if (err < 0)
     37		return XDP_DROP;
     38
     39	return XDP_PASS;
     40}
     41
     42char _license[] SEC("license") = "GPL";