1 #include <linux/bpf.h>
2 #include <bpf/bpf_helpers.h>
3 #include <bpf/bpf_endian.h>
4
5 SEC("sk_skb1")
6 int bpf_prog1(struct __sk_buff *skb)
7 {
8 void *data_end = (void *)(long) skb->data_end;
9 void *data = (void *)(long) skb->data;
10 __u8 *d = data;
11 int err;
12
13 if (data + 10 > data_end) {
14 err = bpf_skb_pull_data(skb, 10);
15 if (err)
16 return SK_DROP;
17
18 data_end = (void *)(long)skb->data_end;
19 data = (void *)(long)skb->data;
20 if (data + 10 > data_end)
21 return SK_DROP;
22 }
23
24 /* This write/read is a bit pointless but tests the verifier and
25 * strparser handler for read/write pkt data and access into sk
26 * fields.
27 */
28 d = data;
29 d[7] = 1;
30 return skb->len;
31 }
32
33 char _license[] SEC("license") = "GPL";
34
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