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/bpf_helpers.h> |
10 | |
11 | struct { |
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 | |
19 | struct { |
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 | |
27 | SEC("tc" ) |
28 | int _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 | |
57 | char _license[] SEC("license" ) = "GPL" ; |
58 | |