1bd4aed0eSJiong Wang // SPDX-License-Identifier: GPL-2.0
2bd4aed0eSJiong Wang // Copyright (c) 2018 Facebook
3bd4aed0eSJiong Wang
4bd4aed0eSJiong Wang #include <linux/bpf.h>
5bd4aed0eSJiong Wang #include <linux/pkt_cls.h>
6bd4aed0eSJiong Wang
7bd4aed0eSJiong Wang #include <string.h>
8bd4aed0eSJiong Wang
93e689141SToke Høiland-Jørgensen #include <bpf/bpf_helpers.h>
10bd4aed0eSJiong Wang
11bd4aed0eSJiong Wang #define NUM_CGROUP_LEVELS 4
12bd4aed0eSJiong Wang
13*ccc3f569SAndrii Nakryiko struct {
14*ccc3f569SAndrii Nakryiko __uint(type, BPF_MAP_TYPE_ARRAY);
15*ccc3f569SAndrii Nakryiko __type(key, __u32);
16*ccc3f569SAndrii Nakryiko __type(value, __u64);
17*ccc3f569SAndrii Nakryiko __uint(max_entries, NUM_CGROUP_LEVELS);
18*ccc3f569SAndrii Nakryiko } cgroup_ids SEC(".maps");
19bd4aed0eSJiong Wang
log_nth_level(struct __sk_buff * skb,__u32 level)20bd4aed0eSJiong Wang static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level)
21bd4aed0eSJiong Wang {
22bd4aed0eSJiong Wang __u64 id;
23bd4aed0eSJiong Wang
24bd4aed0eSJiong Wang /* [1] &level passed to external function that may change it, it's
25bd4aed0eSJiong Wang * incompatible with loop unroll.
26bd4aed0eSJiong Wang */
27bd4aed0eSJiong Wang id = bpf_skb_ancestor_cgroup_id(skb, level);
28bd4aed0eSJiong Wang bpf_map_update_elem(&cgroup_ids, &level, &id, 0);
29bd4aed0eSJiong Wang }
30bd4aed0eSJiong Wang
31bd4aed0eSJiong Wang SEC("cgroup_id_logger")
log_cgroup_id(struct __sk_buff * skb)32bd4aed0eSJiong Wang int log_cgroup_id(struct __sk_buff *skb)
33bd4aed0eSJiong Wang {
34bd4aed0eSJiong Wang /* Loop unroll can't be used here due to [1]. Unrolling manually.
35bd4aed0eSJiong Wang * Number of calls should be in sync with NUM_CGROUP_LEVELS.
36bd4aed0eSJiong Wang */
37bd4aed0eSJiong Wang log_nth_level(skb, 0);
38bd4aed0eSJiong Wang log_nth_level(skb, 1);
39bd4aed0eSJiong Wang log_nth_level(skb, 2);
40bd4aed0eSJiong Wang log_nth_level(skb, 3);
41bd4aed0eSJiong Wang
42bd4aed0eSJiong Wang return TC_ACT_OK;
43bd4aed0eSJiong Wang }
44bd4aed0eSJiong Wang
45bd4aed0eSJiong Wang char _license[] SEC("license") = "GPL";
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