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
12int _version SEC("version") = 1;
13char _license[] SEC("license") = "GPL";
14
15struct {
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
25SEC("sockops")
26int _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