cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
Log | Files | Refs | README | LICENSE | sfeed.txt

test_xdp_adjust_tail_shrink.c (1058B)

      1// SPDX-License-Identifier: GPL-2.0
      2/* Copyright (c) 2018 Facebook
      3 *
      4 * This program is free software; you can redistribute it and/or
      5 * modify it under the terms of version 2 of the GNU General Public
      6 * License as published by the Free Software Foundation.
      7 */
      8#include <linux/bpf.h>
      9#include <linux/if_ether.h>
     10#include <bpf/bpf_helpers.h>
     11
     12SEC("xdp")
     13int _xdp_adjust_tail_shrink(struct xdp_md *xdp)
     14{
     15	__u8 *data_end = (void *)(long)xdp->data_end;
     16	__u8 *data = (void *)(long)xdp->data;
     17	int offset = 0;
     18
     19	switch (bpf_xdp_get_buff_len(xdp)) {
     20	case 54:
     21		/* sizeof(pkt_v4) */
     22		offset = 256; /* shrink too much */
     23		break;
     24	case 9000:
     25		/* non-linear buff test cases */
     26		if (data + 1 > data_end)
     27			return XDP_DROP;
     28
     29		switch (data[0]) {
     30		case 0:
     31			offset = 10;
     32			break;
     33		case 1:
     34			offset = 4100;
     35			break;
     36		case 2:
     37			offset = 8200;
     38			break;
     39		default:
     40			return XDP_DROP;
     41		}
     42		break;
     43	default:
     44		offset = 20;
     45		break;
     46	}
     47	if (bpf_xdp_adjust_tail(xdp, 0 - offset))
     48		return XDP_DROP;
     49	return XDP_TX;
     50}
     51
     52char _license[] SEC("license") = "GPL";