1// SPDX-License-Identifier: GPL-2.0
2#include <linux/bpf.h>
3#include <bpf/bpf_helpers.h>
4
5char _license[] SEC("license") = "GPL";
6
7struct tcp_rtt_storage {
8	__u32 invoked;
9	__u32 dsack_dups;
10	__u32 delivered;
11	__u32 delivered_ce;
12	__u32 icsk_retransmits;
13};
14
15struct {
16	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
17	__uint(map_flags, BPF_F_NO_PREALLOC);
18	__type(key, int);
19	__type(value, struct tcp_rtt_storage);
20} socket_storage_map SEC(".maps");
21
22SEC("sockops")
23int _sockops(struct bpf_sock_ops *ctx)
24{
25	struct tcp_rtt_storage *storage;
26	struct bpf_tcp_sock *tcp_sk;
27	int op = (int) ctx->op;
28	struct bpf_sock *sk;
29
30	sk = ctx->sk;
31	if (!sk)
32		return 1;
33
34	storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
35				     BPF_SK_STORAGE_GET_F_CREATE);
36	if (!storage)
37		return 1;
38
39	if (op == BPF_SOCK_OPS_TCP_CONNECT_CB) {
40		bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
41		return 1;
42	}
43
44	if (op != BPF_SOCK_OPS_RTT_CB)
45		return 1;
46
47	tcp_sk = bpf_tcp_sock(sk);
48	if (!tcp_sk)
49		return 1;
50
51	storage->invoked++;
52
53	storage->dsack_dups = tcp_sk->dsack_dups;
54	storage->delivered = tcp_sk->delivered;
55	storage->delivered_ce = tcp_sk->delivered_ce;
56	storage->icsk_retransmits = tcp_sk->icsk_retransmits;
57
58	return 1;
59}
60