162306a36Sopenharmony_ci/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com 262306a36Sopenharmony_ci * 362306a36Sopenharmony_ci * This program is free software; you can redistribute it and/or 462306a36Sopenharmony_ci * modify it under the terms of version 2 of the GNU General Public 562306a36Sopenharmony_ci * License as published by the Free Software Foundation. 662306a36Sopenharmony_ci */ 762306a36Sopenharmony_ci#include "vmlinux.h" 862306a36Sopenharmony_ci#include "net_shared.h" 962306a36Sopenharmony_ci#include <linux/version.h> 1062306a36Sopenharmony_ci#include <bpf/bpf_helpers.h> 1162306a36Sopenharmony_ci#include <bpf/bpf_core_read.h> 1262306a36Sopenharmony_ci#include <bpf/bpf_tracing.h> 1362306a36Sopenharmony_ci 1462306a36Sopenharmony_ci/* kprobe is NOT a stable ABI 1562306a36Sopenharmony_ci * kernel functions can be removed, renamed or completely change semantics. 1662306a36Sopenharmony_ci * Number of arguments and their positions can change, etc. 1762306a36Sopenharmony_ci * In such case this bpf+kprobe example will no longer be meaningful 1862306a36Sopenharmony_ci */ 1962306a36Sopenharmony_ciSEC("kprobe.multi/__netif_receive_skb_core*") 2062306a36Sopenharmony_ciint bpf_prog1(struct pt_regs *ctx) 2162306a36Sopenharmony_ci{ 2262306a36Sopenharmony_ci /* attaches to kprobe __netif_receive_skb_core, 2362306a36Sopenharmony_ci * looks for packets on loobpack device and prints them 2462306a36Sopenharmony_ci * (wildcard is used for avoiding symbol mismatch due to optimization) 2562306a36Sopenharmony_ci */ 2662306a36Sopenharmony_ci char devname[IFNAMSIZ]; 2762306a36Sopenharmony_ci struct net_device *dev; 2862306a36Sopenharmony_ci struct sk_buff *skb; 2962306a36Sopenharmony_ci int len; 3062306a36Sopenharmony_ci 3162306a36Sopenharmony_ci bpf_core_read(&skb, sizeof(skb), (void *)PT_REGS_PARM1(ctx)); 3262306a36Sopenharmony_ci dev = BPF_CORE_READ(skb, dev); 3362306a36Sopenharmony_ci len = BPF_CORE_READ(skb, len); 3462306a36Sopenharmony_ci 3562306a36Sopenharmony_ci BPF_CORE_READ_STR_INTO(&devname, dev, name); 3662306a36Sopenharmony_ci 3762306a36Sopenharmony_ci if (devname[0] == 'l' && devname[1] == 'o') { 3862306a36Sopenharmony_ci char fmt[] = "skb %p len %d\n"; 3962306a36Sopenharmony_ci /* using bpf_trace_printk() for DEBUG ONLY */ 4062306a36Sopenharmony_ci bpf_trace_printk(fmt, sizeof(fmt), skb, len); 4162306a36Sopenharmony_ci } 4262306a36Sopenharmony_ci 4362306a36Sopenharmony_ci return 0; 4462306a36Sopenharmony_ci} 4562306a36Sopenharmony_ci 4662306a36Sopenharmony_cichar _license[] SEC("license") = "GPL"; 4762306a36Sopenharmony_ciu32 _version SEC("version") = LINUX_VERSION_CODE; 48