projects / linux-block.git / blame
| Commit | Line | Data |
|---|---|---|
| b896c4f9 AS |
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 <uapi/linux/bpf.h> | |
| 10 | #include <linux/version.h> | |
| 7cf245a3 THJ |
11 | #include <bpf/bpf_helpers.h> |
| 12 | #include <bpf/bpf_tracing.h> | |
| b896c4f9 | 13 | |
| e4d9c232 IL |
14 | #define _(P) \ |
| 15 | ({ \ | |
| 16 | typeof(P) val = 0; \ | |
| 17 | bpf_probe_read_kernel(&val, sizeof(val), &(P)); \ | |
| 18 | val; \ | |
| 19 | }) | |
| b896c4f9 AS |
20 | |
| 21 | /* kprobe is NOT a stable ABI | |
| 22 | * kernel functions can be removed, renamed or completely change semantics. | |
| 23 | * Number of arguments and their positions can change, etc. | |
| 24 | * In such case this bpf+kprobe example will no longer be meaningful | |
| 25 | */ | |
| 26 | SEC("kprobe/__netif_receive_skb_core") | |
| 27 | int bpf_prog1(struct pt_regs *ctx) | |
| 28 | { | |
| 137733d0 | 29 | /* attaches to kprobe __netif_receive_skb_core, |
| b896c4f9 AS |
30 | * looks for packets on loobpack device and prints them |
| 31 | */ | |
| 02413cab | 32 | char devname[IFNAMSIZ]; |
| b896c4f9 AS |
33 | struct net_device *dev; |
| 34 | struct sk_buff *skb; | |
| 35 | int len; | |
| 36 | ||
| 37 | /* non-portable! works for the given kernel only */ | |
| 137733d0 | 38 | bpf_probe_read_kernel(&skb, sizeof(skb), (void *)PT_REGS_PARM1(ctx)); |
| b896c4f9 | 39 | dev = _(skb->dev); |
| b896c4f9 AS |
40 | len = _(skb->len); |
| 41 | ||
| e4d9c232 | 42 | bpf_probe_read_kernel(devname, sizeof(devname), dev->name); |
| b896c4f9 AS |
43 | |
| 44 | if (devname[0] == 'l' && devname[1] == 'o') { | |
| 45 | char fmt[] = "skb %p len %d\n"; | |
| 46 | /* using bpf_trace_printk() for DEBUG ONLY */ | |
| 47 | bpf_trace_printk(fmt, sizeof(fmt), skb, len); | |
| 48 | } | |
| 49 | ||
| 50 | return 0; | |
| 51 | } | |
| 52 | ||
| 53 | char _license[] SEC("license") = "GPL"; | |
| 54 | u32 _version SEC("version") = LINUX_VERSION_CODE; |