1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bpf.h> 3 #include <bpf/bpf_helpers.h> 4 #include "bpf_legacy.h" 5 6 struct { 7 __uint(type, BPF_MAP_TYPE_PROG_ARRAY); 8 __uint(max_entries, 1); 9 __uint(key_size, sizeof(__u32)); 10 __uint(value_size, sizeof(__u32)); 11 } jmp_table SEC(".maps"); 12 13 static __noinline 14 int subprog_tail(struct __sk_buff *skb) 15 { 16 if (load_byte(skb, 0)) 17 bpf_tail_call_static(skb, &jmp_table, 1); 18 else 19 bpf_tail_call_static(skb, &jmp_table, 0); 20 return 1; 21 } 22 23 static volatile int count; 24 25 SEC("classifier/0") 26 int bpf_func_0(struct __sk_buff *skb) 27 { 28 count++; 29 return subprog_tail(skb); 30 } 31 32 SEC("classifier") 33 int entry(struct __sk_buff *skb) 34 { 35 bpf_tail_call_static(skb, &jmp_table, 0); 36 37 return 0; 38 } 39 40 char __license[] SEC("license") = "GPL"; 41 int _version SEC("version") = 1; 42