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