/* 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 <net/ip.h>#include <bpf/bpf_helpers.h> #define DEFAULT_PKTGEN_UDP_PORT 9 /* copy of 'struct ethhdr' without __packed */struct eth_hdr {	unsigned char   h_dest[ETH_ALEN];	unsigned char   h_source[ETH_ALEN];	unsigned short  h_proto;}; SEC("simple")int handle_ingress(struct __sk_buff *skb){	void *data = (void *)(long)skb->data;	struct eth_hdr *eth = data;	struct iphdr *iph = data + sizeof(*eth);	struct udphdr *udp = data + sizeof(*eth) + sizeof(*iph);	void *data_end = (void *)(long)skb->data_end; 	/* single length check */	if (data + sizeof(*eth) + sizeof(*iph) + sizeof(*udp) > data_end)		return 0; 	if (eth->h_proto != htons(ETH_P_IP))		return 0;	if (iph->protocol != IPPROTO_UDP || iph->ihl != 5)		return 0;	if (ip_is_fragment(iph))		return 0;	if (udp->dest == htons(DEFAULT_PKTGEN_UDP_PORT))		return TC_ACT_SHOT;	return 0;}char _license[] SEC("license") = "GPL";