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1/* SPDX-License-Identifier: GPL-2.0 */2// Copyright (c) 2018 Politecnico di Torino3#include <stddef.h>4#include <string.h>5#include <linux/bpf.h>6#include <linux/if_ether.h>7#include <linux/ip.h>8#include <linux/pkt_cls.h>9#include <bpf/bpf_helpers.h>10 11struct {12 __uint(type, MAP_TYPE);13 __uint(max_entries, 32);14 __uint(map_flags, 0);15 __uint(key_size, 0);16 __uint(value_size, sizeof(__u32));17} map_in SEC(".maps");18 19struct {20 __uint(type, MAP_TYPE);21 __uint(max_entries, 32);22 __uint(map_flags, 0);23 __uint(key_size, 0);24 __uint(value_size, sizeof(__u32));25} map_out SEC(".maps");26 27SEC("tc")28int _test(struct __sk_buff *skb)29{30 void *data_end = (void *)(long)skb->data_end;31 void *data = (void *)(long)skb->data;32 struct ethhdr *eth = (struct ethhdr *)(data);33 __u32 value;34 int err;35 36 if (eth + 1 > data_end)37 return TC_ACT_SHOT;38 39 struct iphdr *iph = (struct iphdr *)(eth + 1);40 41 if (iph + 1 > data_end)42 return TC_ACT_SHOT;43 44 err = bpf_map_pop_elem(&map_in, &value);45 if (err)46 return TC_ACT_SHOT;47 48 iph->daddr = value;49 50 err = bpf_map_push_elem(&map_out, &iph->saddr, 0);51 if (err)52 return TC_ACT_SHOT;53 54 return TC_ACT_OK;55}56 57char _license[] SEC("license") = "GPL";58