54 lines
1.2 KiB
C
54 lines
1.2 KiB
C
#include <linux/bpf.h>
|
|
#include <linux/if_ether.h>
|
|
#include <linux/pkt_cls.h>
|
|
|
|
#include <bpf/bpf_helpers.h>
|
|
|
|
#define __round_mask(x, y) ((__typeof__(x))((y) - 1))
|
|
#define round_up(x, y) ((((x) - 1) | __round_mask(x, y)) + 1)
|
|
#define ctx_ptr(ctx, mem) (void *)(unsigned long)ctx->mem
|
|
|
|
SEC("t")
|
|
int ing_cls(struct __sk_buff *ctx)
|
|
{
|
|
__u8 *data, *data_meta, *data_end;
|
|
__u32 diff = 0;
|
|
|
|
data_meta = ctx_ptr(ctx, data_meta);
|
|
data_end = ctx_ptr(ctx, data_end);
|
|
data = ctx_ptr(ctx, data);
|
|
|
|
if (data + ETH_ALEN > data_end ||
|
|
data_meta + round_up(ETH_ALEN, 4) > data)
|
|
return TC_ACT_SHOT;
|
|
|
|
diff |= ((__u32 *)data_meta)[0] ^ ((__u32 *)data)[0];
|
|
diff |= ((__u16 *)data_meta)[2] ^ ((__u16 *)data)[2];
|
|
|
|
return diff ? TC_ACT_SHOT : TC_ACT_OK;
|
|
}
|
|
|
|
SEC("x")
|
|
int ing_xdp(struct xdp_md *ctx)
|
|
{
|
|
__u8 *data, *data_meta, *data_end;
|
|
int ret;
|
|
|
|
ret = bpf_xdp_adjust_meta(ctx, -round_up(ETH_ALEN, 4));
|
|
if (ret < 0)
|
|
return XDP_DROP;
|
|
|
|
data_meta = ctx_ptr(ctx, data_meta);
|
|
data_end = ctx_ptr(ctx, data_end);
|
|
data = ctx_ptr(ctx, data);
|
|
|
|
if (data + ETH_ALEN > data_end ||
|
|
data_meta + round_up(ETH_ALEN, 4) > data)
|
|
return XDP_DROP;
|
|
|
|
__builtin_memcpy(data_meta, data, ETH_ALEN);
|
|
return XDP_PASS;
|
|
}
|
|
|
|
char _license[] SEC("license") = "GPL";
|