1/* SPDX-License-Identifier: GPL-2.0 */
2/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
3
4#ifndef _CGRP_KFUNC_COMMON_H
5#define _CGRP_KFUNC_COMMON_H
6
7#include <errno.h>
8#include <vmlinux.h>
9#include <bpf/bpf_helpers.h>
10#include <bpf/bpf_tracing.h>
11
12struct __cgrps_kfunc_map_value {
13	struct cgroup __kptr * cgrp;
14};
15
16struct hash_map {
17	__uint(type, BPF_MAP_TYPE_HASH);
18	__type(key, int);
19	__type(value, struct __cgrps_kfunc_map_value);
20	__uint(max_entries, 1);
21} __cgrps_kfunc_map SEC(".maps");
22
23struct cgroup *bpf_cgroup_acquire(struct cgroup *p) __ksym;
24void bpf_cgroup_release(struct cgroup *p) __ksym;
25struct cgroup *bpf_cgroup_ancestor(struct cgroup *cgrp, int level) __ksym;
26struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
27void bpf_rcu_read_lock(void) __ksym;
28void bpf_rcu_read_unlock(void) __ksym;
29
30static inline struct __cgrps_kfunc_map_value *cgrps_kfunc_map_value_lookup(struct cgroup *cgrp)
31{
32	s32 id;
33	long status;
34
35	status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id);
36	if (status)
37		return NULL;
38
39	return bpf_map_lookup_elem(&__cgrps_kfunc_map, &id);
40}
41
42static inline int cgrps_kfunc_map_insert(struct cgroup *cgrp)
43{
44	struct __cgrps_kfunc_map_value local, *v;
45	long status;
46	struct cgroup *acquired, *old;
47	s32 id;
48
49	status = bpf_probe_read_kernel(&id, sizeof(id), &cgrp->self.id);
50	if (status)
51		return status;
52
53	local.cgrp = NULL;
54	status = bpf_map_update_elem(&__cgrps_kfunc_map, &id, &local, BPF_NOEXIST);
55	if (status)
56		return status;
57
58	v = bpf_map_lookup_elem(&__cgrps_kfunc_map, &id);
59	if (!v) {
60		bpf_map_delete_elem(&__cgrps_kfunc_map, &id);
61		return -ENOENT;
62	}
63
64	acquired = bpf_cgroup_acquire(cgrp);
65	if (!acquired) {
66		bpf_map_delete_elem(&__cgrps_kfunc_map, &id);
67		return -ENOENT;
68	}
69
70	old = bpf_kptr_xchg(&v->cgrp, acquired);
71	if (old) {
72		bpf_cgroup_release(old);
73		return -EEXIST;
74	}
75
76	return 0;
77}
78
79#endif /* _CGRP_KFUNC_COMMON_H */
80