bpf/progs/tailcall2.c

0001 // SPDX-License-Identifier: GPL-2.0
0002 #include <linux/bpf.h>
0003
0004 #include <bpf/bpf_helpers.h>
0005
0006 struct {
0007     __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
0008     __uint(max_entries, 5);
0009     __uint(key_size, sizeof(__u32));
0010     __uint(value_size, sizeof(__u32));
0011 } jmp_table SEC(".maps");
0012
0013 SEC("tc")
0014 int classifier_0(struct __sk_buff *skb)
0015 {
0016     bpf_tail_call_static(skb, &jmp_table, 1);
0017     return 0;
0018 }
0019
0020 SEC("tc")
0021 int classifier_1(struct __sk_buff *skb)
0022 {
0023     bpf_tail_call_static(skb, &jmp_table, 2);
0024     return 1;
0025 }
0026
0027 SEC("tc")
0028 int classifier_2(struct __sk_buff *skb)
0029 {
0030     return 2;
0031 }
0032
0033 SEC("tc")
0034 int classifier_3(struct __sk_buff *skb)
0035 {
0036     bpf_tail_call_static(skb, &jmp_table, 4);
0037     return 3;
0038 }
0039
0040 SEC("tc")
0041 int classifier_4(struct __sk_buff *skb)
0042 {
0043     bpf_tail_call_static(skb, &jmp_table, 3);
0044     return 4;
0045 }
0046
0047 SEC("tc")
0048 int entry(struct __sk_buff *skb)
0049 {
0050     bpf_tail_call_static(skb, &jmp_table, 0);
0051     /* Check multi-prog update. */
0052     bpf_tail_call_static(skb, &jmp_table, 2);
0053     /* Check tail call limit. */
0054     bpf_tail_call_static(skb, &jmp_table, 3);
0055     return 3;
0056 }
0057
0058 char __license[] SEC("license") = "GPL";