1 | // SPDX-License-Identifier: GPL-2.0 |
2 | #include <stdint.h> |
3 | #include <stdbool.h> |
4 | |
5 | #include <linux/bpf.h> |
6 | #include <linux/stddef.h> |
7 | #include <linux/pkt_cls.h> |
8 | #include <linux/if_ether.h> |
9 | #include <linux/ip.h> |
10 | |
11 | #include <bpf/bpf_helpers.h> |
12 | |
13 | volatile const __u32 IFINDEX_SRC; |
14 | volatile const __u32 IFINDEX_DST; |
15 | |
16 | static const __u8 src_mac[] = {0x00, 0x11, 0x22, 0x33, 0x44, 0x55}; |
17 | static const __u8 dst_mac[] = {0x00, 0x22, 0x33, 0x44, 0x55, 0x66}; |
18 | |
19 | SEC("tc" ) |
20 | int tc_chk(struct __sk_buff *skb) |
21 | { |
22 | return TC_ACT_SHOT; |
23 | } |
24 | |
25 | SEC("tc" ) |
26 | int tc_dst(struct __sk_buff *skb) |
27 | { |
28 | return bpf_redirect_peer(IFINDEX_SRC, 0); |
29 | } |
30 | |
31 | SEC("tc" ) |
32 | int tc_src(struct __sk_buff *skb) |
33 | { |
34 | return bpf_redirect_peer(IFINDEX_DST, 0); |
35 | } |
36 | |
37 | SEC("tc" ) |
38 | int tc_dst_l3(struct __sk_buff *skb) |
39 | { |
40 | return bpf_redirect(IFINDEX_SRC, 0); |
41 | } |
42 | |
43 | SEC("tc" ) |
44 | int tc_src_l3(struct __sk_buff *skb) |
45 | { |
46 | __u16 proto = skb->protocol; |
47 | |
48 | if (bpf_skb_change_head(skb, ETH_HLEN, 0) != 0) |
49 | return TC_ACT_SHOT; |
50 | |
51 | if (bpf_skb_store_bytes(skb, 0, &src_mac, ETH_ALEN, 0) != 0) |
52 | return TC_ACT_SHOT; |
53 | |
54 | if (bpf_skb_store_bytes(skb, ETH_ALEN, &dst_mac, ETH_ALEN, 0) != 0) |
55 | return TC_ACT_SHOT; |
56 | |
57 | if (bpf_skb_store_bytes(skb, ETH_ALEN + ETH_ALEN, &proto, sizeof(__u16), 0) != 0) |
58 | return TC_ACT_SHOT; |
59 | |
60 | return bpf_redirect_peer(IFINDEX_DST, 0); |
61 | } |
62 | |
63 | char __license[] SEC("license" ) = "GPL" ; |
64 | |