tracex2_kern.c (2395B)
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;