1 #include <linux/bpf.h>
2 #include <bpf/bpf_helpers.h>
3 #include <bpf/bpf_endian.h>
4 
5 struct {
6 	__uint(type, BPF_MAP_TYPE_SOCKMAP);
7 	__uint(max_entries, 20);
8 	__type(key, int);
9 	__type(value, int);
10 } sock_map_rx SEC(".maps");
11 
12 struct {
13 	__uint(type, BPF_MAP_TYPE_SOCKMAP);
14 	__uint(max_entries, 20);
15 	__type(key, int);
16 	__type(value, int);
17 } sock_map_tx SEC(".maps");
18 
19 struct {
20 	__uint(type, BPF_MAP_TYPE_SOCKMAP);
21 	__uint(max_entries, 20);
22 	__type(key, int);
23 	__type(value, int);
24 } sock_map_msg SEC(".maps");
25 
26 struct {
27 	__uint(type, BPF_MAP_TYPE_ARRAY);
28 	__uint(max_entries, 20);
29 	__type(key, int);
30 	__type(value, int);
31 } sock_map_break SEC(".maps");
32 
33 SEC("sk_skb2")
34 int bpf_prog2(struct __sk_buff *skb)
35 {
36 	void *data_end = (void *)(long) skb->data_end;
37 	void *data = (void *)(long) skb->data;
38 	__u32 lport = skb->local_port;
39 	__u32 rport = skb->remote_port;
40 	__u8 *d = data;
41 	__u8 sk, map;
42 
43 	if (data + 8 > data_end)
44 		return SK_DROP;
45 
46 	map = d[0];
47 	sk = d[1];
48 
49 	d[0] = 0xd;
50 	d[1] = 0xe;
51 	d[2] = 0xa;
52 	d[3] = 0xd;
53 	d[4] = 0xb;
54 	d[5] = 0xe;
55 	d[6] = 0xe;
56 	d[7] = 0xf;
57 
58 	if (!map)
59 		return bpf_sk_redirect_map(skb, &sock_map_rx, sk, 0);
60 	return bpf_sk_redirect_map(skb, &sock_map_tx, sk, 0);
61 }
62 
63 char _license[] SEC("license") = "GPL";
64