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// SPDX-License-Identifier: GPL-2.0
#include <linux/bpf.h>
#include <bpf/bpf_helpers.h>
#include "bpf_misc.h"
#include "bpf_test_utils.h"
int classifier_0(struct __sk_buff *skb);
struct {
__uint(type, BPF_MAP_TYPE_PROG_ARRAY);
__uint(max_entries, 1);
__uint(key_size, sizeof(__u32));
__array(values, void (void));
} jmp_table SEC(".maps") = {
.values = {
[0] = (void *) &classifier_0,
},
};
__auxiliary
SEC("tc")
int classifier_0(struct __sk_buff *skb)
{
return 0;
}
static __noinline
int subprog_tail0(struct __sk_buff *skb)
{
int ret = 0;
bpf_tail_call_static(skb, &jmp_table, 0);
barrier_var(ret);
return ret;
}
static __noinline
int callback_loop(int index, void **cb_ctx)
{
int ret;
ret = subprog_tail0(*cb_ctx);
barrier_var(ret);
return ret ? 1 : 0;
}
static __noinline
int callback_empty(int index, void *data)
{
return 0;
}
/* callback involving subprog with tail call is rejected */
SEC("tc")
__failure __msg("cannot tail call within callback")
int tailcall_callback_1(struct __sk_buff *skb)
{
clobber_regs_stack();
bpf_loop(1, callback_loop, &skb, 0);
return 0;
}
/* subprogs with tailcall do not affect no-tailcall callback */
SEC("tc")
__success
__retval(0)
int tailcall_callback_2(struct __sk_buff *skb)
{
int ret;
clobber_regs_stack();
ret = subprog_tail0(skb);
__sink(ret);
bpf_loop(1, callback_empty, NULL, 0);
return 0;
}
char __license[] SEC("license") = "GPL";
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