tools/testing/selftests/bpf/progs/sockmap_parse_prog.c

   1 #include <linux/bpf.h>
   2 #include "bpf_helpers.h"
   3 #include "bpf_endian.h"
   4
   5 int _version SEC("version") = 1;
   6
   7 SEC("sk_skb1")
   8 int bpf_prog1(struct __sk_buff *skb)
   9 {
  10         void *data_end = (void *)(long) skb->data_end;
  11         void *data = (void *)(long) skb->data;
  12         __u32 lport = skb->local_port;
  13         __u32 rport = skb->remote_port;
  14         __u8 *d = data;
  15         __u32 len = (__u32) data_end - (__u32) data;
  16         int err;
  17
  18         if (data + 10 > data_end) {
  19                 err = bpf_skb_pull_data(skb, 10);
  20                 if (err)
  21                         return SK_DROP;
  22
  23                 data_end = (void *)(long)skb->data_end;
  24                 data = (void *)(long)skb->data;
  25                 if (data + 10 > data_end)
  26                         return SK_DROP;
  27         }
  28
  29         /* This write/read is a bit pointless but tests the verifier and
  30          * strparser handler for read/write pkt data and access into sk
  31          * fields.
  32          */
  33         d = data;
  34         d[7] = 1;
  35         return skb->len;
  36 }
  37
  38 char _license[] SEC("license") = "GPL";