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// SPDX-License-Identifier: GPL-2.0
// Copyright (c) 2018 Facebook
#include <linux/bpf.h>
#include <linux/pkt_cls.h>
#include <string.h>
#include <bpf/bpf_helpers.h>
#define NUM_CGROUP_LEVELS 4
struct bpf_map_def SEC("maps") cgroup_ids = {
.type = BPF_MAP_TYPE_ARRAY,
.key_size = sizeof(__u32),
.value_size = sizeof(__u64),
.max_entries = NUM_CGROUP_LEVELS,
};
static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level)
{
__u64 id;
/* [1] &level passed to external function that may change it, it's
* incompatible with loop unroll.
*/
id = bpf_skb_ancestor_cgroup_id(skb, level);
bpf_map_update_elem(&cgroup_ids, &level, &id, 0);
}
SEC("cgroup_id_logger")
int log_cgroup_id(struct __sk_buff *skb)
{
/* Loop unroll can't be used here due to [1]. Unrolling manually.
* Number of calls should be in sync with NUM_CGROUP_LEVELS.
*/
log_nth_level(skb, 0);
log_nth_level(skb, 1);
log_nth_level(skb, 2);
log_nth_level(skb, 3);
return TC_ACT_OK;
}
int _version SEC("version") = 1;
char _license[] SEC("license") = "GPL";
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