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_skb_cgroup_id_kern.c (1020B)

      1// SPDX-License-Identifier: GPL-2.0
      2// Copyright (c) 2018 Facebook
      3
      4#include <linux/bpf.h>
      5#include <linux/pkt_cls.h>
      6
      7#include <string.h>
      8
      9#include <bpf/bpf_helpers.h>
     10
     11#define NUM_CGROUP_LEVELS	4
     12
     13struct {
     14	__uint(type, BPF_MAP_TYPE_ARRAY);
     15	__type(key, __u32);
     16	__type(value, __u64);
     17	__uint(max_entries, NUM_CGROUP_LEVELS);
     18} cgroup_ids SEC(".maps");
     19
     20static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level)
     21{
     22	__u64 id;
     23
     24	/* [1] &level passed to external function that may change it, it's
     25	 *     incompatible with loop unroll.
     26	 */
     27	id = bpf_skb_ancestor_cgroup_id(skb, level);
     28	bpf_map_update_elem(&cgroup_ids, &level, &id, 0);
     29}
     30
     31SEC("cgroup_id_logger")
     32int log_cgroup_id(struct __sk_buff *skb)
     33{
     34	/* Loop unroll can't be used here due to [1]. Unrolling manually.
     35	 * Number of calls should be in sync with NUM_CGROUP_LEVELS.
     36	 */
     37	log_nth_level(skb, 0);
     38	log_nth_level(skb, 1);
     39	log_nth_level(skb, 2);
     40	log_nth_level(skb, 3);
     41
     42	return TC_ACT_OK;
     43}
     44
     45char _license[] SEC("license") = "GPL";