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 bpf_map_def __attribute__ ((section("maps"), used)) map_in = {
14 .type = MAP_TYPE,
15 .key_size = 0,
16 .value_size = sizeof(__u32),
17 .max_entries = 32,
18 .map_flags = 0,
19};
20
21struct bpf_map_def __attribute__ ((section("maps"), used)) map_out = {
22 .type = MAP_TYPE,
23 .key_size = 0,
24 .value_size = sizeof(__u32),
25 .max_entries = 32,
26 .map_flags = 0,
27};
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";