| 1 | |
| 2 | #include <vmlinux.h>
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| 3 | #include <bpf/bpf_helpers.h>
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| 4 |
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| 5 | #include "bpf_misc.h"
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| 6 |
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| 7 | struct hmap_elem {
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| 8 | struct bpf_timer timer;
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| 9 | };
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| 10 |
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| 11 | struct {
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| 12 | __uint(type, BPF_MAP_TYPE_HASH);
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| 13 | __uint(max_entries, 64);
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| 14 | __type(key, int);
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| 15 | __type(value, struct hmap_elem);
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| 16 | } hmap SEC(".maps");
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| 17 |
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| 18 | __attribute__((noinline))
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| 19 | static int timer_cb(void *map, int *key, struct bpf_timer *timer)
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| 20 | {
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| 21 | volatile char buf[256] = {};
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| 22 | return buf[69];
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| 23 | }
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| 24 |
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| 25 | __attribute__((noinline))
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| 26 | static int bad_timer_cb(void *map, int *key, struct bpf_timer *timer)
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| 27 | {
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| 28 | volatile char buf[300] = {};
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| 29 | return buf[255] + timer_cb(NULL, NULL, NULL);
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| 30 | }
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| 31 |
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| 32 | SEC("tc")
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| 33 | __failure __msg("combined stack size of 2 calls is")
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| 34 | int pseudo_call_check(struct __sk_buff *ctx)
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| 35 | {
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| 36 | struct hmap_elem *elem;
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| 37 | volatile char buf[256] = {};
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| 38 |
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| 39 | elem = bpf_map_lookup_elem(&hmap, &(int){0});
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| 40 | if (!elem)
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| 41 | return 0;
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| 42 |
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| 43 | timer_cb(NULL, NULL, NULL);
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| 44 | return bpf_timer_set_callback(&elem->timer, timer_cb) + buf[0];
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| 45 | }
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| 46 |
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| 47 | SEC("tc")
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| 48 | __failure __msg("combined stack size of 2 calls is")
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| 49 | int async_call_root_check(struct __sk_buff *ctx)
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| 50 | {
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| 51 | struct hmap_elem *elem;
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| 52 | volatile char buf[256] = {};
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| 53 |
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| 54 | elem = bpf_map_lookup_elem(&hmap, &(int){0});
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| 55 | if (!elem)
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| 56 | return 0;
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| 57 |
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| 58 | return bpf_timer_set_callback(&elem->timer, bad_timer_cb) + buf[0];
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| 59 | }
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| 60 |
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| 61 | char _license[] SEC("license") = "GPL";
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