Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
1/* SPDX-License-Identifier: GPL-2.0 */
2// Copyright (c) 2018 Politecnico di Torino
3#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_helpers.h"
10
11int _version SEC("version") = 1;
12
13struct {
14 __uint(type, MAP_TYPE);
15 __uint(max_entries, 32);
16 __uint(map_flags, 0);
17 __uint(key_size, 0);
18 __uint(value_size, sizeof(__u32));
19} map_in SEC(".maps");
20
21struct {
22 __uint(type, MAP_TYPE);
23 __uint(max_entries, 32);
24 __uint(map_flags, 0);
25 __uint(key_size, 0);
26 __uint(value_size, sizeof(__u32));
27} map_out SEC(".maps");
28
29SEC("test")
30int _test(struct __sk_buff *skb)
31{
32 void *data_end = (void *)(long)skb->data_end;
33 void *data = (void *)(long)skb->data;
34 struct ethhdr *eth = (struct ethhdr *)(data);
35 __u32 value;
36 int err;
37
38 if (eth + 1 > data_end)
39 return TC_ACT_SHOT;
40
41 struct iphdr *iph = (struct iphdr *)(eth + 1);
42
43 if (iph + 1 > data_end)
44 return TC_ACT_SHOT;
45
46 err = bpf_map_pop_elem(&map_in, &value);
47 if (err)
48 return TC_ACT_SHOT;
49
50 iph->daddr = value;
51
52 err = bpf_map_push_elem(&map_out, &iph->saddr, 0);
53 if (err)
54 return TC_ACT_SHOT;
55
56 return TC_ACT_OK;
57}
58
59char _license[] SEC("license") = "GPL";