// 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";