34 lines · c
1#include <linux/bpf.h>2#include <bpf/bpf_helpers.h>3#include <bpf/bpf_endian.h>4 5SEC("sk_skb1")6int 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 and25 * strparser handler for read/write pkt data and access into sk26 * fields.27 */28 d = data;29 d[7] = 1;30 return skb->len;31}32 33char _license[] SEC("license") = "GPL";34