1 // SPDX-License-Identifier: GPL-2.0
2
3 #include "vmlinux.h"
4
5 #include <bpf/bpf_helpers.h>
6 #include <bpf/bpf_tracing.h>
7
8 char _license[] SEC("license") = "GPL";
9
10 #define USEC_PER_SEC 1000000UL
11
12 #define min(a, b) ((a) < (b) ? (a) : (b))
13
tcp_sk(const struct sock * sk)14 static inline struct tcp_sock *tcp_sk(const struct sock *sk)
15 {
16 return (struct tcp_sock *)sk;
17 }
18
tcp_left_out(const struct tcp_sock * tp)19 static inline unsigned int tcp_left_out(const struct tcp_sock *tp)
20 {
21 return tp->sacked_out + tp->lost_out;
22 }
23
tcp_packets_in_flight(const struct tcp_sock * tp)24 static inline unsigned int tcp_packets_in_flight(const struct tcp_sock *tp)
25 {
26 return tp->packets_out - tcp_left_out(tp) + tp->retrans_out;
27 }
28
29 SEC("struct_ops/write_sk_pacing_init")
BPF_PROG(write_sk_pacing_init,struct sock * sk)30 void BPF_PROG(write_sk_pacing_init, struct sock *sk)
31 {
32 #ifdef ENABLE_ATOMICS_TESTS
33 __sync_bool_compare_and_swap(&sk->sk_pacing_status, SK_PACING_NONE,
34 SK_PACING_NEEDED);
35 #else
36 sk->sk_pacing_status = SK_PACING_NEEDED;
37 #endif
38 }
39
40 SEC("struct_ops/write_sk_pacing_cong_control")
BPF_PROG(write_sk_pacing_cong_control,struct sock * sk,const struct rate_sample * rs)41 void BPF_PROG(write_sk_pacing_cong_control, struct sock *sk,
42 const struct rate_sample *rs)
43 {
44 struct tcp_sock *tp = tcp_sk(sk);
45 unsigned long rate =
46 ((tp->snd_cwnd * tp->mss_cache * USEC_PER_SEC) << 3) /
47 (tp->srtt_us ?: 1U << 3);
48 sk->sk_pacing_rate = min(rate, sk->sk_max_pacing_rate);
49 tp->app_limited = (tp->delivered + tcp_packets_in_flight(tp)) ?: 1;
50 }
51
52 SEC("struct_ops/write_sk_pacing_ssthresh")
BPF_PROG(write_sk_pacing_ssthresh,struct sock * sk)53 __u32 BPF_PROG(write_sk_pacing_ssthresh, struct sock *sk)
54 {
55 return tcp_sk(sk)->snd_ssthresh;
56 }
57
58 SEC("struct_ops/write_sk_pacing_undo_cwnd")
BPF_PROG(write_sk_pacing_undo_cwnd,struct sock * sk)59 __u32 BPF_PROG(write_sk_pacing_undo_cwnd, struct sock *sk)
60 {
61 return tcp_sk(sk)->snd_cwnd;
62 }
63
64 SEC(".struct_ops")
65 struct tcp_congestion_ops write_sk_pacing = {
66 .init = (void *)write_sk_pacing_init,
67 .cong_control = (void *)write_sk_pacing_cong_control,
68 .ssthresh = (void *)write_sk_pacing_ssthresh,
69 .undo_cwnd = (void *)write_sk_pacing_undo_cwnd,
70 .name = "bpf_w_sk_pacing",
71 };
72