| 1 | #include "vmlinux.h" |
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| 2 | #include <linux/version.h> |
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| 3 | #include <bpf/bpf_helpers.h> |
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| 4 | #include <bpf/bpf_tracing.h> |
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| 5 | #include <bpf/bpf_core_read.h> |
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| 6 | |
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| 7 | struct { |
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| 8 | __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); |
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| 9 | __uint(key_size, sizeof(int)); |
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| 10 | __uint(value_size, sizeof(u32)); |
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| 11 | __uint(max_entries, 64); |
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| 12 | } counters SEC(".maps" ); |
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| 13 | |
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| 14 | struct { |
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| 15 | __uint(type, BPF_MAP_TYPE_HASH); |
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| 16 | __type(key, int); |
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| 17 | __type(value, u64); |
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| 18 | __uint(max_entries, 64); |
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| 19 | } values SEC(".maps" ); |
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| 20 | |
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| 21 | struct { |
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| 22 | __uint(type, BPF_MAP_TYPE_HASH); |
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| 23 | __type(key, int); |
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| 24 | __type(value, struct bpf_perf_event_value); |
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| 25 | __uint(max_entries, 64); |
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| 26 | } values2 SEC(".maps" ); |
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| 27 | |
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| 28 | SEC("kprobe/htab_map_get_next_key" ) |
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| 29 | int bpf_prog1(struct pt_regs *ctx) |
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| 30 | { |
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| 31 | u32 key = bpf_get_smp_processor_id(); |
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| 32 | u64 count, *val; |
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| 33 | s64 error; |
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| 34 | |
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| 35 | count = bpf_perf_event_read(&counters, key); |
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| 36 | error = (s64)count; |
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| 37 | if (error <= -2 && error >= -22) |
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| 38 | return 0; |
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| 39 | |
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| 40 | val = bpf_map_lookup_elem(&values, &key); |
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| 41 | if (val) |
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| 42 | *val = count; |
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| 43 | else |
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| 44 | bpf_map_update_elem(&values, &key, &count, BPF_NOEXIST); |
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| 45 | |
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| 46 | return 0; |
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| 47 | } |
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| 48 | |
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| 49 | /* |
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| 50 | * Since *_map_lookup_elem can't be expected to trigger bpf programs |
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| 51 | * due to potential deadlocks (bpf_disable_instrumentation), this bpf |
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| 52 | * program will be attached to bpf_map_copy_value (which is called |
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| 53 | * from map_lookup_elem) and will only filter the hashtable type. |
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| 54 | */ |
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| 55 | SEC("kprobe/bpf_map_copy_value" ) |
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| 56 | int BPF_KPROBE(bpf_prog2, struct bpf_map *map) |
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| 57 | { |
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| 58 | u32 key = bpf_get_smp_processor_id(); |
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| 59 | struct bpf_perf_event_value *val, buf; |
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| 60 | enum bpf_map_type type; |
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| 61 | int error; |
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| 62 | |
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| 63 | type = BPF_CORE_READ(map, map_type); |
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| 64 | if (type != BPF_MAP_TYPE_HASH) |
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| 65 | return 0; |
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| 66 | |
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| 67 | error = bpf_perf_event_read_value(&counters, key, &buf, sizeof(buf)); |
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| 68 | if (error) |
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| 69 | return 0; |
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| 70 | |
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| 71 | val = bpf_map_lookup_elem(&values2, &key); |
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| 72 | if (val) |
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| 73 | *val = buf; |
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| 74 | else |
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| 75 | bpf_map_update_elem(&values2, &key, &buf, BPF_NOEXIST); |
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| 76 | |
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| 77 | return 0; |
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| 78 | } |
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| 79 | |
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| 80 | char _license[] SEC("license" ) = "GPL" ; |
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| 81 | u32 _version SEC("version" ) = LINUX_VERSION_CODE; |
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| 82 | |
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