/* 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 "vmlinux.h" #include <bpf/bpf_helpers.h> struct { __uint(type, BPF_MAP_TYPE_PERCPU_HASH); __type(key, u64); __type(value, u64); __uint(pinning, LIBBPF_PIN_BY_NAME); __uint(max_entries, 1024); } lwt_len_hist_map SEC(".maps"); 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";