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-rw-r--r--tools/testing/selftests/bpf/progs/cgroup_ancestor.c40
1 files changed, 40 insertions, 0 deletions
diff --git a/tools/testing/selftests/bpf/progs/cgroup_ancestor.c b/tools/testing/selftests/bpf/progs/cgroup_ancestor.c
new file mode 100644
index 000000000000..8c2deb4fc493
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/cgroup_ancestor.c
@@ -0,0 +1,40 @@
+// 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";