/* Copyright (c) 2016 Facebook
 *
 * 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.
 */
#define KBUILD_MODNAME "foo"
#include <linux/ip.h>
#include <linux/ipv6.h>
#include <linux/in.h>
#include <linux/tcp.h>
#include <linux/udp.h>
#include <uapi/linux/bpf.h>
#include "bpf_helpers.h"

#define DEFAULT_PKTGEN_UDP_PORT	9
#define IP_MF			0x2000
#define IP_OFFSET		0x1FFF

static inline int ip_is_fragment(struct __sk_buff *ctx, __u64 nhoff)
{
	return load_half(ctx, nhoff + offsetof(struct iphdr, frag_off))
		& (IP_MF | IP_OFFSET);
}

SEC("ldabs")
int handle_ingress(struct __sk_buff *skb)
{
	__u64 troff = ETH_HLEN + sizeof(struct iphdr);

	if (load_half(skb, offsetof(struct ethhdr, h_proto)) != ETH_P_IP)
		return 0;
	if (load_byte(skb, ETH_HLEN + offsetof(struct iphdr, protocol)) != IPPROTO_UDP ||
	    load_byte(skb, ETH_HLEN) != 0x45)
		return 0;
	if (ip_is_fragment(skb, ETH_HLEN))
		return 0;
	if (load_half(skb, troff + offsetof(struct udphdr, dest)) == DEFAULT_PKTGEN_UDP_PORT)
		return TC_ACT_SHOT;
	return 0;
}
char _license[] SEC("license") = "GPL";
<option value='packet-loop-back'>packet-loop-back</option>
<option value='packet-rx-pump-back'>packet-rx-pump-back</option>
</select> <input type='submit' value='switch'/></form></td></tr>
<tr><td class='sub'>net-next plumbings</td><td class='sub right'>Tobias Klauser</td></tr></table>
<table class='tabs'><tr><td>
<a href='/cgit.cgi/linux/net-next.git/?h=nds-private-remove'>summary</a><a href='/cgit.cgi/linux/net-next.git/refs/?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>refs</a><a class='active' href='/cgit.cgi/linux/net-next.git/log/tools/cgroup/.gitignore?h=nds-private-remove'>log</a><a href='/cgit.cgi/linux/net-next.git/tree/tools/cgroup/.gitignore?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>tree</a><a href='/cgit.cgi/linux/net-next.git/commit/tools/cgroup/.gitignore?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>commit</a><a href='/cgit.cgi/linux/net-next.git/diff/tools/cgroup/.gitignore?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>diff</a></td><td class='form'><form class='right' method='get' action='/cgit.cgi/linux/net-next.git/log/tools/cgroup/.gitignore'>
<input type='hidden' name='h' value='nds-private-remove'/><input type='hidden' name='id' value='ff548773106ec7f8031bc6172e0234bd2a02c19c'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/cgit.cgi/linux/net-next.git/log/?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>root</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>tools</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools/cgroup?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>cgroup</a>/<a href='/cgit.cgi/linux/net-next.git/log/tools/cgroup/.gitignore?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c'>.gitignore</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/tools/cgroup/.gitignore?h=nds-private-remove&amp;id=ff548773106ec7f8031bc6172e0234bd2a02c19c&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th><th class='left'>Files</th><th class='left'>Lines</th></tr>