1/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
  2 *
  3 * This program is free software; you can redistribute it and/or
  4 * modify it under the terms of version 2 of the GNU General Public
  5 * License as published by the Free Software Foundation.
  6 */
  7#include <linux/skbuff.h>
  8#include <linux/netdevice.h>
  9#include <linux/version.h>
 10#include <uapi/linux/bpf.h>
 11#include <bpf/bpf_helpers.h>
 12#include <bpf/bpf_tracing.h>
 13#include "trace_common.h"
 14
 15struct {
 16	__uint(type, BPF_MAP_TYPE_HASH);
 17	__type(key, long);
 18	__type(value, long);
 19	__uint(max_entries, 1024);
 20} my_map SEC(".maps");
 21
 22/* kprobe is NOT a stable ABI. If kernel internals change this bpf+kprobe
 23 * example will no longer be meaningful
 24 */
 25SEC("kprobe/kfree_skb")
 26int bpf_prog2(struct pt_regs *ctx)
 27{
 28	long loc = 0;
 29	long init_val = 1;
 30	long *value;
 31
 32	/* read ip of kfree_skb caller.
 33	 * non-portable version of __builtin_return_address(0)
 34	 */
 35	BPF_KPROBE_READ_RET_IP(loc, ctx);
 36
 37	value = bpf_map_lookup_elem(&my_map, &loc);
 38	if (value)
 39		*value += 1;
 40	else
 41		bpf_map_update_elem(&my_map, &loc, &init_val, BPF_ANY);
 42	return 0;
 43}
 44
 45static unsigned int log2(unsigned int v)
 46{
 47	unsigned int r;
 48	unsigned int shift;
 49
 50	r = (v > 0xFFFF) << 4; v >>= r;
 51	shift = (v > 0xFF) << 3; v >>= shift; r |= shift;
 52	shift = (v > 0xF) << 2; v >>= shift; r |= shift;
 53	shift = (v > 0x3) << 1; v >>= shift; r |= shift;
 54	r |= (v >> 1);
 55	return r;
 56}
 57
 58static unsigned int log2l(unsigned long v)
 59{
 60	unsigned int hi = v >> 32;
 61	if (hi)
 62		return log2(hi) + 32;
 63	else
 64		return log2(v);
 65}
 66
 67struct hist_key {
 68	char comm[16];
 69	u64 pid_tgid;
 70	u64 uid_gid;
 71	u64 index;
 72};
 73
 74struct {
 75	__uint(type, BPF_MAP_TYPE_PERCPU_HASH);
 76	__uint(key_size, sizeof(struct hist_key));
 77	__uint(value_size, sizeof(long));
 78	__uint(max_entries, 1024);
 79} my_hist_map SEC(".maps");
 80
 81SEC("kprobe/" SYSCALL(sys_write))
 82int bpf_prog3(struct pt_regs *ctx)
 83{
 84	long write_size = PT_REGS_PARM3(ctx);
 85	long init_val = 1;
 86	long *value;
 87	struct hist_key key;
 88
 89	key.index = log2l(write_size);
 90	key.pid_tgid = bpf_get_current_pid_tgid();
 91	key.uid_gid = bpf_get_current_uid_gid();
 92	bpf_get_current_comm(&key.comm, sizeof(key.comm));
 93
 94	value = bpf_map_lookup_elem(&my_hist_map, &key);
 95	if (value)
 96		__sync_fetch_and_add(value, 1);
 97	else
 98		bpf_map_update_elem(&my_hist_map, &key, &init_val, BPF_ANY);
 99	return 0;
100}
101char _license[] SEC("license") = "GPL";
102u32 _version SEC("version") = LINUX_VERSION_CODE;