1*e04946f5SDaniel T. Lee /* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
2*e04946f5SDaniel T. Lee *
3*e04946f5SDaniel T. Lee * This program is free software; you can redistribute it and/or
4*e04946f5SDaniel T. Lee * modify it under the terms of version 2 of the GNU General Public
5*e04946f5SDaniel T. Lee * License as published by the Free Software Foundation.
6*e04946f5SDaniel T. Lee *
7*e04946f5SDaniel T. Lee * This program is distributed in the hope that it will be useful, but
8*e04946f5SDaniel T. Lee * WITHOUT ANY WARRANTY; without even the implied warranty of
9*e04946f5SDaniel T. Lee * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
10*e04946f5SDaniel T. Lee * General Public License for more details.
11*e04946f5SDaniel T. Lee */
12*e04946f5SDaniel T. Lee
13*e04946f5SDaniel T. Lee #include "vmlinux.h"
14*e04946f5SDaniel T. Lee #include <bpf/bpf_helpers.h>
15*e04946f5SDaniel T. Lee
16*e04946f5SDaniel T. Lee struct {
17*e04946f5SDaniel T. Lee __uint(type, BPF_MAP_TYPE_PERCPU_HASH);
18*e04946f5SDaniel T. Lee __type(key, u64);
19*e04946f5SDaniel T. Lee __type(value, u64);
20*e04946f5SDaniel T. Lee __uint(pinning, LIBBPF_PIN_BY_NAME);
21*e04946f5SDaniel T. Lee __uint(max_entries, 1024);
22*e04946f5SDaniel T. Lee } lwt_len_hist_map SEC(".maps");
23*e04946f5SDaniel T. Lee
log2(unsigned int v)24*e04946f5SDaniel T. Lee static unsigned int log2(unsigned int v)
25*e04946f5SDaniel T. Lee {
26*e04946f5SDaniel T. Lee unsigned int r;
27*e04946f5SDaniel T. Lee unsigned int shift;
28*e04946f5SDaniel T. Lee
29*e04946f5SDaniel T. Lee r = (v > 0xFFFF) << 4; v >>= r;
30*e04946f5SDaniel T. Lee shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
31*e04946f5SDaniel T. Lee shift = (v > 0xF) << 2; v >>= shift; r |= shift;
32*e04946f5SDaniel T. Lee shift = (v > 0x3) << 1; v >>= shift; r |= shift;
33*e04946f5SDaniel T. Lee r |= (v >> 1);
34*e04946f5SDaniel T. Lee return r;
35*e04946f5SDaniel T. Lee }
36*e04946f5SDaniel T. Lee
log2l(unsigned long v)37*e04946f5SDaniel T. Lee static unsigned int log2l(unsigned long v)
38*e04946f5SDaniel T. Lee {
39*e04946f5SDaniel T. Lee unsigned int hi = v >> 32;
40*e04946f5SDaniel T. Lee if (hi)
41*e04946f5SDaniel T. Lee return log2(hi) + 32;
42*e04946f5SDaniel T. Lee else
43*e04946f5SDaniel T. Lee return log2(v);
44*e04946f5SDaniel T. Lee }
45*e04946f5SDaniel T. Lee
46*e04946f5SDaniel T. Lee SEC("len_hist")
do_len_hist(struct __sk_buff * skb)47*e04946f5SDaniel T. Lee int do_len_hist(struct __sk_buff *skb)
48*e04946f5SDaniel T. Lee {
49*e04946f5SDaniel T. Lee __u64 *value, key, init_val = 1;
50*e04946f5SDaniel T. Lee
51*e04946f5SDaniel T. Lee key = log2l(skb->len);
52*e04946f5SDaniel T. Lee
53*e04946f5SDaniel T. Lee value = bpf_map_lookup_elem(&lwt_len_hist_map, &key);
54*e04946f5SDaniel T. Lee if (value)
55*e04946f5SDaniel T. Lee __sync_fetch_and_add(value, 1);
56*e04946f5SDaniel T. Lee else
57*e04946f5SDaniel T. Lee bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY);
58*e04946f5SDaniel T. Lee
59*e04946f5SDaniel T. Lee return BPF_OK;
60*e04946f5SDaniel T. Lee }
61*e04946f5SDaniel T. Lee
62*e04946f5SDaniel T. Lee char _license[] SEC("license") = "GPL";
63