79 lines
1.3 KiB
C
79 lines
1.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <linux/bpf.h>
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#include <bpf/bpf_helpers.h>
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struct {
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__uint(type, BPF_MAP_TYPE_ARRAY);
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__uint(max_entries, 1);
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__uint(key_size, sizeof(__u32));
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__uint(value_size, sizeof(__u32));
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} nop_table SEC(".maps");
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struct {
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__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
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__uint(max_entries, 3);
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__uint(key_size, sizeof(__u32));
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__uint(value_size, sizeof(__u32));
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} jmp_table SEC(".maps");
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int count = 0;
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int noise = 0;
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static __always_inline int subprog_noise(void)
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{
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__u32 key = 0;
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bpf_map_lookup_elem(&nop_table, &key);
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return 0;
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}
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__noinline
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int subprog_tail_2(struct __sk_buff *skb)
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{
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if (noise)
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subprog_noise();
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bpf_tail_call_static(skb, &jmp_table, 2);
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return skb->len * 3;
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}
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__noinline
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int subprog_tail_1(struct __sk_buff *skb)
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{
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bpf_tail_call_static(skb, &jmp_table, 1);
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return skb->len * 2;
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}
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__noinline
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int subprog_tail(struct __sk_buff *skb)
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{
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bpf_tail_call_static(skb, &jmp_table, 0);
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return skb->len;
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}
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SEC("tc")
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int classifier_1(struct __sk_buff *skb)
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{
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return subprog_tail_2(skb);
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}
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SEC("tc")
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int classifier_2(struct __sk_buff *skb)
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{
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count++;
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return subprog_tail_2(skb);
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}
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SEC("tc")
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int classifier_0(struct __sk_buff *skb)
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{
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return subprog_tail_1(skb);
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}
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SEC("tc")
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int entry(struct __sk_buff *skb)
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{
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return subprog_tail(skb);
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}
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char __license[] SEC("license") = "GPL";
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