text: #include <uapi/linux/bpf.h>
  #include "bpf_helpers.h"
  
  SEC("sk_skb/simple-lt")
  int prog_simple_lt(struct __sk_buff *skb)
  {
  	long *data = (void *)(long)skb->data;
  	long *data_end = (void *)(long)skb->data_end;
  	unsigned long k = data_end - data;
  	if (k <= 48) return 1;
  	*data = 1;
  	return 1;
  }
  
  char _license[] SEC("license") = "GPL";
  u32 _version SEC("version") = 0x041800;
  