/* 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/bpf_helpers.h>#include "bpf_legacy.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";