/* 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_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";