1 // SPDX-License-Identifier: GPL-2.0
2 #include <linux/bpf.h>
3 #include <bpf/bpf_helpers.h>
4
5 char _license[] SEC("license") = "GPL";
6
7 struct 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
18 struct {
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
25 SEC("sockops")
26 int _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
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