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	__u32 mrtt_us;	/* args[0] */
15	__u32 srtt;	/* args[1] */
16};
17
18struct {
19	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
20	__uint(map_flags, BPF_F_NO_PREALLOC);
21	__type(key, int);
22	__type(value, struct tcp_rtt_storage);
23} socket_storage_map SEC(".maps");
24
25SEC("sockops")
26int _sockops(struct bpf_sock_ops *ctx)
27{
28	struct tcp_rtt_storage *storage;
29	struct bpf_tcp_sock *tcp_sk;
30	int op = (int) ctx->op;
31	struct bpf_sock *sk;
32
33	sk = ctx->sk;
34	if (!sk)
35		return 1;
36
37	storage = bpf_sk_storage_get(&socket_storage_map, sk, 0,
38				     BPF_SK_STORAGE_GET_F_CREATE);
39	if (!storage)
40		return 1;
41
42	if (op == BPF_SOCK_OPS_TCP_CONNECT_CB) {
43		bpf_sock_ops_cb_flags_set(ctx, BPF_SOCK_OPS_RTT_CB_FLAG);
44		return 1;
45	}
46
47	if (op != BPF_SOCK_OPS_RTT_CB)
48		return 1;
49
50	tcp_sk = bpf_tcp_sock(sk);
51	if (!tcp_sk)
52		return 1;
53
54	storage->invoked++;
55
56	storage->dsack_dups = tcp_sk->dsack_dups;
57	storage->delivered = tcp_sk->delivered;
58	storage->delivered_ce = tcp_sk->delivered_ce;
59	storage->icsk_retransmits = tcp_sk->icsk_retransmits;
60
61	storage->mrtt_us = ctx->args[0];
62	storage->srtt = ctx->args[1];
63
64	return 1;
65}
66