1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bpf.h> 3 4 #include <bpf/bpf_helpers.h> 5 6 struct { 7 __uint(type, BPF_MAP_TYPE_PROG_ARRAY); 8 __uint(max_entries, 3); 9 __uint(key_size, sizeof(__u32)); 10 __uint(value_size, sizeof(__u32)); 11 } jmp_table SEC(".maps"); 12 13 #define TAIL_FUNC(x) \ 14 SEC("tc") \ 15 int classifier_##x(struct __sk_buff *skb) \ 16 { \ 17 return x; \ 18 } 19 TAIL_FUNC(0) 20 TAIL_FUNC(1) 21 TAIL_FUNC(2) 22 23 SEC("tc") 24 int entry(struct __sk_buff *skb) 25 { 26 /* Multiple locations to make sure we patch 27 * all of them. 28 */ 29 bpf_tail_call_static(skb, &jmp_table, 0); 30 bpf_tail_call_static(skb, &jmp_table, 0); 31 bpf_tail_call_static(skb, &jmp_table, 0); 32 bpf_tail_call_static(skb, &jmp_table, 0); 33 34 bpf_tail_call_static(skb, &jmp_table, 1); 35 bpf_tail_call_static(skb, &jmp_table, 1); 36 bpf_tail_call_static(skb, &jmp_table, 1); 37 bpf_tail_call_static(skb, &jmp_table, 1); 38 39 bpf_tail_call_static(skb, &jmp_table, 2); 40 bpf_tail_call_static(skb, &jmp_table, 2); 41 bpf_tail_call_static(skb, &jmp_table, 2); 42 bpf_tail_call_static(skb, &jmp_table, 2); 43 44 return 3; 45 } 46 47 char __license[] SEC("license") = "GPL"; 48