1*4882a593Smuzhiyun /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
2*4882a593Smuzhiyun *
3*4882a593Smuzhiyun * This program is free software; you can redistribute it and/or
4*4882a593Smuzhiyun * modify it under the terms of version 2 of the GNU General Public
5*4882a593Smuzhiyun * License as published by the Free Software Foundation.
6*4882a593Smuzhiyun *
7*4882a593Smuzhiyun * This program is distributed in the hope that it will be useful, but
8*4882a593Smuzhiyun * WITHOUT ANY WARRANTY; without even the implied warranty of
9*4882a593Smuzhiyun * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10*4882a593Smuzhiyun * General Public License for more details.
11*4882a593Smuzhiyun */
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun #include <uapi/linux/bpf.h>
14*4882a593Smuzhiyun #include <uapi/linux/if_ether.h>
15*4882a593Smuzhiyun #include <uapi/linux/ip.h>
16*4882a593Smuzhiyun #include <uapi/linux/in.h>
17*4882a593Smuzhiyun #include <bpf/bpf_helpers.h>
18*4882a593Smuzhiyun
19*4882a593Smuzhiyun # define printk(fmt, ...) \
20*4882a593Smuzhiyun ({ \
21*4882a593Smuzhiyun char ____fmt[] = fmt; \
22*4882a593Smuzhiyun bpf_trace_printk(____fmt, sizeof(____fmt), \
23*4882a593Smuzhiyun ##__VA_ARGS__); \
24*4882a593Smuzhiyun })
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun struct bpf_elf_map {
27*4882a593Smuzhiyun __u32 type;
28*4882a593Smuzhiyun __u32 size_key;
29*4882a593Smuzhiyun __u32 size_value;
30*4882a593Smuzhiyun __u32 max_elem;
31*4882a593Smuzhiyun __u32 flags;
32*4882a593Smuzhiyun __u32 id;
33*4882a593Smuzhiyun __u32 pinning;
34*4882a593Smuzhiyun };
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun struct bpf_elf_map SEC("maps") lwt_len_hist_map = {
37*4882a593Smuzhiyun .type = BPF_MAP_TYPE_PERCPU_HASH,
38*4882a593Smuzhiyun .size_key = sizeof(__u64),
39*4882a593Smuzhiyun .size_value = sizeof(__u64),
40*4882a593Smuzhiyun .pinning = 2,
41*4882a593Smuzhiyun .max_elem = 1024,
42*4882a593Smuzhiyun };
43*4882a593Smuzhiyun
log2(unsigned int v)44*4882a593Smuzhiyun static unsigned int log2(unsigned int v)
45*4882a593Smuzhiyun {
46*4882a593Smuzhiyun unsigned int r;
47*4882a593Smuzhiyun unsigned int shift;
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun r = (v > 0xFFFF) << 4; v >>= r;
50*4882a593Smuzhiyun shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
51*4882a593Smuzhiyun shift = (v > 0xF) << 2; v >>= shift; r |= shift;
52*4882a593Smuzhiyun shift = (v > 0x3) << 1; v >>= shift; r |= shift;
53*4882a593Smuzhiyun r |= (v >> 1);
54*4882a593Smuzhiyun return r;
55*4882a593Smuzhiyun }
56*4882a593Smuzhiyun
log2l(unsigned long v)57*4882a593Smuzhiyun static unsigned int log2l(unsigned long v)
58*4882a593Smuzhiyun {
59*4882a593Smuzhiyun unsigned int hi = v >> 32;
60*4882a593Smuzhiyun if (hi)
61*4882a593Smuzhiyun return log2(hi) + 32;
62*4882a593Smuzhiyun else
63*4882a593Smuzhiyun return log2(v);
64*4882a593Smuzhiyun }
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun SEC("len_hist")
do_len_hist(struct __sk_buff * skb)67*4882a593Smuzhiyun int do_len_hist(struct __sk_buff *skb)
68*4882a593Smuzhiyun {
69*4882a593Smuzhiyun __u64 *value, key, init_val = 1;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun key = log2l(skb->len);
72*4882a593Smuzhiyun
73*4882a593Smuzhiyun value = bpf_map_lookup_elem(&lwt_len_hist_map, &key);
74*4882a593Smuzhiyun if (value)
75*4882a593Smuzhiyun __sync_fetch_and_add(value, 1);
76*4882a593Smuzhiyun else
77*4882a593Smuzhiyun bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY);
78*4882a593Smuzhiyun
79*4882a593Smuzhiyun return BPF_OK;
80*4882a593Smuzhiyun }
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun char _license[] SEC("license") = "GPL";
83