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12#include <linux/mm.h>
13#include <linux/module.h>
14#include <linux/skbuff.h>
15#include <linux/inet_diag.h>
16
17#include <net/tcp.h>
18
19
20
21
22#define V_PARAM_SHIFT 1
23static const int beta = 3 << V_PARAM_SHIFT;
24
25
26struct veno {
27 u8 doing_veno_now;
28 u16 cntrtt;
29 u32 minrtt;
30 u32 basertt;
31 u32 inc;
32 u32 diff;
33};
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42
43
44static inline void veno_enable(struct sock *sk)
45{
46 struct veno *veno = inet_csk_ca(sk);
47
48
49 veno->doing_veno_now = 1;
50
51 veno->minrtt = 0x7fffffff;
52}
53
54static inline void veno_disable(struct sock *sk)
55{
56 struct veno *veno = inet_csk_ca(sk);
57
58
59 veno->doing_veno_now = 0;
60}
61
62static void tcp_veno_init(struct sock *sk)
63{
64 struct veno *veno = inet_csk_ca(sk);
65
66 veno->basertt = 0x7fffffff;
67 veno->inc = 1;
68 veno_enable(sk);
69}
70
71
72static void tcp_veno_pkts_acked(struct sock *sk, u32 cnt, s32 rtt_us)
73{
74 struct veno *veno = inet_csk_ca(sk);
75 u32 vrtt;
76
77 if (rtt_us < 0)
78 return;
79
80
81 vrtt = rtt_us + 1;
82
83
84 if (vrtt < veno->basertt)
85 veno->basertt = vrtt;
86
87
88
89
90 veno->minrtt = min(veno->minrtt, vrtt);
91 veno->cntrtt++;
92}
93
94static void tcp_veno_state(struct sock *sk, u8 ca_state)
95{
96 if (ca_state == TCP_CA_Open)
97 veno_enable(sk);
98 else
99 veno_disable(sk);
100}
101
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109
110
111static void tcp_veno_cwnd_event(struct sock *sk, enum tcp_ca_event event)
112{
113 if (event == CA_EVENT_CWND_RESTART || event == CA_EVENT_TX_START)
114 tcp_veno_init(sk);
115}
116
117static void tcp_veno_cong_avoid(struct sock *sk, u32 ack, u32 acked)
118{
119 struct tcp_sock *tp = tcp_sk(sk);
120 struct veno *veno = inet_csk_ca(sk);
121
122 if (!veno->doing_veno_now) {
123 tcp_reno_cong_avoid(sk, ack, acked);
124 return;
125 }
126
127
128 if (!tcp_is_cwnd_limited(sk))
129 return;
130
131
132 if (veno->cntrtt <= 2) {
133
134
135
136 tcp_reno_cong_avoid(sk, ack, acked);
137 } else {
138 u64 target_cwnd;
139 u32 rtt;
140
141
142
143
144
145 rtt = veno->minrtt;
146
147 target_cwnd = (u64)tp->snd_cwnd * veno->basertt;
148 target_cwnd <<= V_PARAM_SHIFT;
149 do_div(target_cwnd, rtt);
150
151 veno->diff = (tp->snd_cwnd << V_PARAM_SHIFT) - target_cwnd;
152
153 if (tp->snd_cwnd <= tp->snd_ssthresh) {
154
155 tcp_slow_start(tp, acked);
156 } else {
157
158 if (veno->diff < beta) {
159
160
161
162 tcp_cong_avoid_ai(tp, tp->snd_cwnd, 1);
163 } else {
164
165
166
167 if (tp->snd_cwnd_cnt >= tp->snd_cwnd) {
168 if (veno->inc &&
169 tp->snd_cwnd < tp->snd_cwnd_clamp) {
170 tp->snd_cwnd++;
171 veno->inc = 0;
172 } else
173 veno->inc = 1;
174 tp->snd_cwnd_cnt = 0;
175 } else
176 tp->snd_cwnd_cnt++;
177 }
178 }
179 if (tp->snd_cwnd < 2)
180 tp->snd_cwnd = 2;
181 else if (tp->snd_cwnd > tp->snd_cwnd_clamp)
182 tp->snd_cwnd = tp->snd_cwnd_clamp;
183 }
184
185
186 veno->minrtt = 0x7fffffff;
187}
188
189
190static u32 tcp_veno_ssthresh(struct sock *sk)
191{
192 const struct tcp_sock *tp = tcp_sk(sk);
193 struct veno *veno = inet_csk_ca(sk);
194
195 if (veno->diff < beta)
196
197 return max(tp->snd_cwnd * 4 / 5, 2U);
198 else
199
200 return max(tp->snd_cwnd >> 1U, 2U);
201}
202
203static struct tcp_congestion_ops tcp_veno __read_mostly = {
204 .init = tcp_veno_init,
205 .ssthresh = tcp_veno_ssthresh,
206 .cong_avoid = tcp_veno_cong_avoid,
207 .pkts_acked = tcp_veno_pkts_acked,
208 .set_state = tcp_veno_state,
209 .cwnd_event = tcp_veno_cwnd_event,
210
211 .owner = THIS_MODULE,
212 .name = "veno",
213};
214
215static int __init tcp_veno_register(void)
216{
217 BUILD_BUG_ON(sizeof(struct veno) > ICSK_CA_PRIV_SIZE);
218 tcp_register_congestion_control(&tcp_veno);
219 return 0;
220}
221
222static void __exit tcp_veno_unregister(void)
223{
224 tcp_unregister_congestion_control(&tcp_veno);
225}
226
227module_init(tcp_veno_register);
228module_exit(tcp_veno_unregister);
229
230MODULE_AUTHOR("Bin Zhou, Cheng Peng Fu");
231MODULE_LICENSE("GPL");
232MODULE_DESCRIPTION("TCP Veno");
233