/* SPDX-License-Identifier: GPL-2.0 */// Copyright (c) 2018 Politecnico di Torino#include <stddef.h>#include <string.h>#include <linux/bpf.h>#include <linux/if_ether.h>#include <linux/ip.h>#include <linux/pkt_cls.h>#include "bpf_helpers.h" int _version SEC("version") = 1; struct bpf_map_def __attribute__ ((section("maps"), used)) map_in = {	.type = MAP_TYPE,	.key_size = 0,	.value_size = sizeof(__u32),	.max_entries = 32,	.map_flags = 0,}; struct bpf_map_def __attribute__ ((section("maps"), used)) map_out = {	.type = MAP_TYPE,	.key_size = 0,	.value_size = sizeof(__u32),	.max_entries = 32,	.map_flags = 0,}; SEC("test")int _test(struct __sk_buff *skb){	void *data_end = (void *)(long)skb->data_end;	void *data = (void *)(long)skb->data;	struct ethhdr *eth = (struct ethhdr *)(data);	__u32 value;	int err; 	if (eth + 1 > data_end)		return TC_ACT_SHOT; 	struct iphdr *iph = (struct iphdr *)(eth + 1); 	if (iph + 1 > data_end)		return TC_ACT_SHOT; 	err = bpf_map_pop_elem(&map_in, &value);	if (err)		return TC_ACT_SHOT; 	iph->daddr = value; 	err = bpf_map_push_elem(&map_out, &iph->saddr, 0);	if (err)		return TC_ACT_SHOT; 	return TC_ACT_OK;} char _license[] SEC("license") = "GPL";