/* Copyright (c) 2013-2015 PLUMgrid, http://plumgrid.com
 *
 * 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.
 */
#include <linux/skbuff.h>
#include <linux/netdevice.h>
#include <uapi/linux/bpf.h>
#include <linux/version.h>
#include "bpf_helpers.h"

#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})

/* kprobe is NOT a stable ABI
 * kernel functions can be removed, renamed or completely change semantics.
 * Number of arguments and their positions can change, etc.
 * In such case this bpf+kprobe example will no longer be meaningful
 */
SEC("kprobe/__netif_receive_skb_core")
int bpf_prog1(struct pt_regs *ctx)
{
	/* attaches to kprobe netif_receive_skb,
	 * looks for packets on loobpack device and prints them
	 */
	char devname[IFNAMSIZ];
	struct net_device *dev;
	struct sk_buff *skb;
	int len;

	/* non-portable! works for the given kernel only */
	skb = (struct sk_buff *) PT_REGS_PARM1(ctx);
	dev = _(skb->dev);
	len = _(skb->len);

	bpf_probe_read(devname, sizeof(devname), dev->name);

	if (devname[0] == 'l' && devname[1] == 'o') {
		char fmt[] = "skb %p len %d\n";
		/* using bpf_trace_printk() for DEBUG ONLY */
		bpf_trace_printk(fmt, sizeof(fmt), skb, len);
	}

	return 0;
}

char _license[] SEC("license") = "GPL";
u32 _version SEC("version") = LINUX_VERSION_CODE;
e>
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<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?id=9665b74562ab95bcf1b0684d599bc6779c433fca'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/include?id=9665b74562ab95bcf1b0684d599bc6779c433fca'>include</a>/<a href='/cgit.cgi/linux/net-next.git/log/include/net?id=9665b74562ab95bcf1b0684d599bc6779c433fca'>net</a>/<a href='/cgit.cgi/linux/net-next.git/log/include/net/cipso_ipv4.h?id=9665b74562ab95bcf1b0684d599bc6779c433fca'>cipso_ipv4.h</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/cgit.cgi/linux/net-next.git/log/include/net/cipso_ipv4.h?id=9665b74562ab95bcf1b0684d599bc6779c433fca&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>
<tr><td><span title='2017-02-04 19:44:22 -0500'>2017-02-04</span></td><td><a href='/cgit.cgi/linux/net-next.git/commit/include/net/cipso_ipv4.h?id=d71b7896886345c53ef1d84bda2bc758554f5d61'>netlabel: out of bound access in cipso_v4_validate()</a></td><td>Eric Dumazet</td><td>1</td><td><span class='deletions'>-0</span>/<span class='insertions'>+4</span></td></tr>