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

lwt_len_hist_kern.c (1738B)

      1/* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
      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 * This program is distributed in the hope that it will be useful, but
      8 * WITHOUT ANY WARRANTY; without even the implied warranty of
      9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
     10 * General Public License for more details.
     11 */
     12
     13#include <uapi/linux/bpf.h>
     14#include <uapi/linux/if_ether.h>
     15#include <uapi/linux/ip.h>
     16#include <uapi/linux/in.h>
     17#include <bpf/bpf_helpers.h>
     18
     19struct bpf_elf_map {
     20	__u32 type;
     21	__u32 size_key;
     22	__u32 size_value;
     23	__u32 max_elem;
     24	__u32 flags;
     25	__u32 id;
     26	__u32 pinning;
     27};
     28
     29struct bpf_elf_map SEC("maps") lwt_len_hist_map = {
     30	.type = BPF_MAP_TYPE_PERCPU_HASH,
     31	.size_key = sizeof(__u64),
     32	.size_value = sizeof(__u64),
     33	.pinning = 2,
     34	.max_elem = 1024,
     35};
     36
     37static unsigned int log2(unsigned int v)
     38{
     39	unsigned int r;
     40	unsigned int shift;
     41
     42	r = (v > 0xFFFF) << 4; v >>= r;
     43	shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
     44	shift = (v > 0xF) << 2; v >>= shift; r |= shift;
     45	shift = (v > 0x3) << 1; v >>= shift; r |= shift;
     46	r |= (v >> 1);
     47	return r;
     48}
     49
     50static unsigned int log2l(unsigned long v)
     51{
     52	unsigned int hi = v >> 32;
     53	if (hi)
     54		return log2(hi) + 32;
     55	else
     56		return log2(v);
     57}
     58
     59SEC("len_hist")
     60int do_len_hist(struct __sk_buff *skb)
     61{
     62	__u64 *value, key, init_val = 1;
     63
     64	key = log2l(skb->len);
     65
     66	value = bpf_map_lookup_elem(&lwt_len_hist_map, &key);
     67	if (value)
     68		__sync_fetch_and_add(value, 1);
     69	else
     70		bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY);
     71
     72	return BPF_OK;
     73}
     74
     75char _license[] SEC("license") = "GPL";