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f74599f7 TG |
1 | /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch> |
2 | * | |
3 | * This program is free software; you can redistribute it and/or | |
4 | * modify it under the terms of version 2 of the GNU General Public | |
5 | * License as published by the Free Software Foundation. | |
6 | * | |
7 | * This program is distributed in the hope that it will be useful, but | |
8 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
9 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
10 | * General Public License for more details. | |
11 | */ | |
12 | ||
13 | #include <uapi/linux/bpf.h> | |
14 | #include <uapi/linux/if_ether.h> | |
15 | #include <uapi/linux/ip.h> | |
16 | #include <uapi/linux/in.h> | |
17 | #include "bpf_helpers.h" | |
18 | ||
19 | # define printk(fmt, ...) \ | |
20 | ({ \ | |
21 | char ____fmt[] = fmt; \ | |
22 | bpf_trace_printk(____fmt, sizeof(____fmt), \ | |
23 | ##__VA_ARGS__); \ | |
24 | }) | |
25 | ||
26 | struct bpf_elf_map { | |
27 | __u32 type; | |
28 | __u32 size_key; | |
29 | __u32 size_value; | |
30 | __u32 max_elem; | |
31 | __u32 flags; | |
32 | __u32 id; | |
33 | __u32 pinning; | |
34 | }; | |
35 | ||
36 | struct bpf_elf_map SEC("maps") lwt_len_hist_map = { | |
37 | .type = BPF_MAP_TYPE_PERCPU_HASH, | |
38 | .size_key = sizeof(__u64), | |
39 | .size_value = sizeof(__u64), | |
40 | .pinning = 2, | |
41 | .max_elem = 1024, | |
42 | }; | |
43 | ||
44 | static unsigned int log2(unsigned int v) | |
45 | { | |
46 | unsigned int r; | |
47 | unsigned int shift; | |
48 | ||
49 | r = (v > 0xFFFF) << 4; v >>= r; | |
50 | shift = (v > 0xFF) << 3; v >>= shift; r |= shift; | |
51 | shift = (v > 0xF) << 2; v >>= shift; r |= shift; | |
52 | shift = (v > 0x3) << 1; v >>= shift; r |= shift; | |
53 | r |= (v >> 1); | |
54 | return r; | |
55 | } | |
56 | ||
57 | static unsigned int log2l(unsigned long v) | |
58 | { | |
59 | unsigned int hi = v >> 32; | |
60 | if (hi) | |
61 | return log2(hi) + 32; | |
62 | else | |
63 | return log2(v); | |
64 | } | |
65 | ||
66 | SEC("len_hist") | |
67 | int do_len_hist(struct __sk_buff *skb) | |
68 | { | |
69 | __u64 *value, key, init_val = 1; | |
70 | ||
71 | key = log2l(skb->len); | |
72 | ||
73 | value = bpf_map_lookup_elem(&lwt_len_hist_map, &key); | |
74 | if (value) | |
75 | __sync_fetch_and_add(value, 1); | |
76 | else | |
77 | bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY); | |
78 | ||
79 | return BPF_OK; | |
80 | } | |
81 | ||
82 | char _license[] SEC("license") = "GPL"; |