1#include <linux/bpf.h>
2#include <linux/if_ether.h>
3#include <linux/pkt_cls.h>
4
5#include <bpf/bpf_helpers.h>
6
7#define __round_mask(x, y) ((__typeof__(x))((y) - 1))
8#define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1)
9#define ctx_ptr(ctx, mem) (void *)(unsigned long)ctx->mem
10
11SEC("t")
12int ing_cls(struct __sk_buff *ctx)
13{
14	__u8 *data, *data_meta, *data_end;
15	__u32 diff = 0;
16
17	data_meta = ctx_ptr(ctx, data_meta);
18	data_end  = ctx_ptr(ctx, data_end);
19	data      = ctx_ptr(ctx, data);
20
21	if (data + ETH_ALEN > data_end ||
22	    data_meta + round_up(ETH_ALEN, 4) > data)
23		return TC_ACT_SHOT;
24
25	diff |= ((__u32 *)data_meta)[0] ^ ((__u32 *)data)[0];
26	diff |= ((__u16 *)data_meta)[2] ^ ((__u16 *)data)[2];
27
28	return diff ? TC_ACT_SHOT : TC_ACT_OK;
29}
30
31SEC("x")
32int ing_xdp(struct xdp_md *ctx)
33{
34	__u8 *data, *data_meta, *data_end;
35	int ret;
36
37	ret = bpf_xdp_adjust_meta(ctx, -round_up(ETH_ALEN, 4));
38	if (ret < 0)
39		return XDP_DROP;
40
41	data_meta = ctx_ptr(ctx, data_meta);
42	data_end  = ctx_ptr(ctx, data_end);
43	data      = ctx_ptr(ctx, data);
44
45	if (data + ETH_ALEN > data_end ||
46	    data_meta + round_up(ETH_ALEN, 4) > data)
47		return XDP_DROP;
48
49	__builtin_memcpy(data_meta, data, ETH_ALEN);
50	return XDP_PASS;
51}
52
53char _license[] SEC("license") = "GPL";
54