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/* Copyright (c) 2016 Thomas Graf <tgraf@tgraf.ch>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*/
#include <uapi/linux/bpf.h>
#include <uapi/linux/if_ether.h>
#include <uapi/linux/ip.h>
#include <uapi/linux/in.h>
#include <bpf/bpf_helpers.h>
# define printk(fmt, ...) \
({ \
char ____fmt[] = fmt; \
bpf_trace_printk(____fmt, sizeof(____fmt), \
##__VA_ARGS__); \
})
struct bpf_elf_map {
__u32 type;
__u32 size_key;
__u32 size_value;
__u32 max_elem;
__u32 flags;
__u32 id;
__u32 pinning;
};
struct bpf_elf_map SEC("maps") lwt_len_hist_map = {
.type = BPF_MAP_TYPE_PERCPU_HASH,
.size_key = sizeof(__u64),
.size_value = sizeof(__u64),
.pinning = 2,
.max_elem = 1024,
};
static unsigned int log2(unsigned int v)
{
unsigned int r;
unsigned int shift;
r = (v > 0xFFFF) << 4; v >>= r;
shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
shift = (v > 0xF) << 2; v >>= shift; r |= shift;
shift = (v > 0x3) << 1; v >>= shift; r |= shift;
r |= (v >> 1);
return r;
}
static unsigned int log2l(unsigned long v)
{
unsigned int hi = v >> 32;
if (hi)
return log2(hi) + 32;
else
return log2(v);
}
SEC("len_hist")
int do_len_hist(struct __sk_buff *skb)
{
__u64 *value, key, init_val = 1;
key = log2l(skb->len);
value = bpf_map_lookup_elem(&lwt_len_hist_map, &key);
if (value)
__sync_fetch_and_add(value, 1);
else
bpf_map_update_elem(&lwt_len_hist_map, &key, &init_val, BPF_ANY);
return BPF_OK;
}
char _license[] SEC("license") = "GPL";
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