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/bpf_helpers.h>
8 #include <bpf/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 }
69