1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/bpf.h> 3 #include <bpf/bpf_helpers.h> 4 5 #define __unused __attribute__((unused)) 6 7 struct { 8 __uint(type, BPF_MAP_TYPE_PROG_ARRAY); 9 __uint(max_entries, 1); 10 __uint(key_size, sizeof(__u32)); 11 __uint(value_size, sizeof(__u32)); 12 } jmp_table SEC(".maps"); 13 14 int done = 0; 15 16 SEC("tc") 17 int classifier_0(struct __sk_buff *skb __unused) 18 { 19 done = 1; 20 return 0; 21 } 22 23 static __noinline 24 int subprog_tail(struct __sk_buff *skb) 25 { 26 /* Don't propagate the constant to the caller */ 27 volatile int ret = 1; 28 29 bpf_tail_call_static(skb, &jmp_table, 0); 30 return ret; 31 } 32 33 SEC("tc") 34 int entry(struct __sk_buff *skb) 35 { 36 /* Have data on stack which size is not a multiple of 8 */ 37 volatile char arr[1] = {}; 38 39 return subprog_tail(skb); 40 } 41 42 char __license[] SEC("license") = "GPL"; 43