62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
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// SPDX-License-Identifier: GPL-2.0
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#include <vmlinux.h>
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#include <bpf/bpf_helpers.h>
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#include "bpf_misc.h"
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struct hmap_elem {
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struct bpf_timer timer;
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};
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struct {
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__uint(type, BPF_MAP_TYPE_HASH);
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__uint(max_entries, 64);
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__type(key, int);
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__type(value, struct hmap_elem);
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} hmap SEC(".maps");
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__attribute__((noinline))
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static int timer_cb(void *map, int *key, struct bpf_timer *timer)
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{
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volatile char buf[256] = {};
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return buf[69];
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}
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__attribute__((noinline))
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static int bad_timer_cb(void *map, int *key, struct bpf_timer *timer)
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{
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volatile char buf[300] = {};
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return buf[255] + timer_cb(NULL, NULL, NULL);
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}
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SEC("tc")
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__failure __msg("combined stack size of 2 calls is 576. Too large")
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int pseudo_call_check(struct __sk_buff *ctx)
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{
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struct hmap_elem *elem;
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volatile char buf[256] = {};
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elem = bpf_map_lookup_elem(&hmap, &(int){0});
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if (!elem)
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return 0;
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timer_cb(NULL, NULL, NULL);
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return bpf_timer_set_callback(&elem->timer, timer_cb) + buf[0];
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}
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SEC("tc")
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__failure __msg("combined stack size of 2 calls is 608. Too large")
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int async_call_root_check(struct __sk_buff *ctx)
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{
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struct hmap_elem *elem;
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volatile char buf[256] = {};
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elem = bpf_map_lookup_elem(&hmap, &(int){0});
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if (!elem)
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return 0;
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return bpf_timer_set_callback(&elem->timer, bad_timer_cb) + buf[0];
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}
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char _license[] SEC("license") = "GPL";
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