root/samples/bpf/tcp_dumpstats_kern.c

DEFINITIONS

1. SEC

   1 // SPDX-License-Identifier: GPL-2.0
   2 /* Refer to samples/bpf/tcp_bpf.readme for the instructions on
   3  * how to run this sample program.
   4  */
   5 #include <linux/bpf.h>
   6 
   7 #include "bpf_helpers.h"
   8 #include "bpf_endian.h"
   9 
  10 #define INTERVAL                        1000000000ULL
  11 
  12 int _version SEC("version") = 1;
  13 char _license[] SEC("license") = "GPL";
  14 
  15 struct {
  16         __u32 type;
  17         __u32 map_flags;
  18         int *key;
  19         __u64 *value;
  20 } bpf_next_dump SEC(".maps") = {
  21         .type = BPF_MAP_TYPE_SK_STORAGE,
  22         .map_flags = BPF_F_NO_PREALLOC,
  23 };
  24 
  25 SEC("sockops")
  26 int _sockops(struct bpf_sock_ops *ctx)
  27 {
  28         struct bpf_tcp_sock *tcp_sk;
  29         struct bpf_sock *sk;
  30         __u64 *next_dump;
  31         __u64 now;
  32 
  33         switch (ctx->op) {
  34         case BPF_SOCK_OPS_TCP_CONNECT_CB:
  35                 bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
  36                 return 1;
  37         case BPF_SOCK_OPS_RTT_CB:
  38                 break;
  39         default:
  40                 return 1;
  41         }
  42 
  43         sk = ctx->sk;
  44         if (!sk)
  45                 return 1;
  46 
  47         next_dump = bpf_sk_storage_get(&bpf_next_dump, sk, 0,
  48                                        BPF_SK_STORAGE_GET_F_CREATE);
  49         if (!next_dump)
  50                 return 1;
  51 
  52         now = bpf_ktime_get_ns();
  53         if (now < *next_dump)
  54                 return 1;
  55 
  56         tcp_sk = bpf_tcp_sock(sk);
  57         if (!tcp_sk)
  58                 return 1;
  59 
  60         *next_dump = now + INTERVAL;
  61 
  62         bpf_printk("dsack_dups=%u delivered=%u\n",
  63                    tcp_sk->dsack_dups, tcp_sk->delivered);
  64         bpf_printk("delivered_ce=%u icsk_retransmits=%u\n",
  65                    tcp_sk->delivered_ce, tcp_sk->icsk_retransmits);
  66 
  67         return 1;
  68 }