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