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/* 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/bpf_helpers.h>
struct {
__uint(type, MAP_TYPE);
__uint(max_entries, 32);
__uint(map_flags, 0);
__uint(key_size, 0);
__uint(value_size, sizeof(__u32));
} map_in SEC(".maps");
struct {
__uint(type, MAP_TYPE);
__uint(max_entries, 32);
__uint(map_flags, 0);
__uint(key_size, 0);
__uint(value_size, sizeof(__u32));
} map_out SEC(".maps");
SEC("tc")
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";
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