// SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2018 Facebook #include <vmlinux.h> #include <bpf/bpf_helpers.h> #include <bpf/bpf_core_read.h> #include "bpf_tracing_net.h" #define NUM_CGROUP_LEVELS 4 __u64 cgroup_ids[NUM_CGROUP_LEVELS]; __u16 dport; static __always_inline void log_nth_level(struct __sk_buff *skb, __u32 level) { /* [1] &level passed to external function that may change it, it's * incompatible with loop unroll. */ cgroup_ids[level] = bpf_skb_ancestor_cgroup_id(skb, level); } SEC("tc") int log_cgroup_id(struct __sk_buff *skb) { struct sock *sk = (void *)skb->sk; if (!sk) return TC_ACT_OK; sk = bpf_core_cast(sk, struct sock); if (sk->sk_protocol == IPPROTO_UDP && sk->sk_dport == dport) { log_nth_level(skb, 0); log_nth_level(skb, 1); log_nth_level(skb, 2); log_nth_level(skb, 3); } return TC_ACT_OK; } char _license[] SEC("license") = "GPL";