FD.io VPP  v18.10-34-gcce845e
Vector Packet Processing
tcp_newreno.c
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1 /*
2  * Copyright (c) 2017 Cisco and/or its affiliates.
3  * Licensed under the Apache License, Version 2.0 (the "License");
4  * you may not use this file except in compliance with the License.
5  * You may obtain a copy of the License at:
6  *
7  * http://www.apache.org/licenses/LICENSE-2.0
8  *
9  * Unless required by applicable law or agreed to in writing, software
10  * distributed under the License is distributed on an "AS IS" BASIS,
11  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12  * See the License for the specific language governing permissions and
13  * limitations under the License.
14  */
15 
16 #include <vnet/tcp/tcp.h>
17 
18 void
20 {
21  tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
22 }
23 
24 void
26 {
27  tc->cwnd = tc->ssthresh;
28 }
29 
30 void
32 {
33  if (tcp_in_slowstart (tc))
34  {
35  tc->cwnd += clib_min (tc->snd_mss, tc->bytes_acked);
36  }
37  else
38  {
39  /* tc->cwnd += clib_max ((tc->snd_mss * tc->snd_mss) / tc->cwnd, 1); */
40  tc->cwnd_acc_bytes += tc->bytes_acked;
41  if (tc->cwnd_acc_bytes >= tc->cwnd)
42  {
43  u32 inc = tc->cwnd_acc_bytes / tc->cwnd;
44  tc->cwnd_acc_bytes -= inc * tc->cwnd;
45  tc->cwnd += inc * tc->snd_mss;
46  }
47  tc->cwnd = clib_min (tc->cwnd,
48  transport_tx_fifo_size (&tc->connection));
49  }
50 }
51 
52 void
54 {
55  if (ack_type == TCP_CC_DUPACK)
56  {
57  if (!tcp_opts_sack_permitted (tc))
58  tc->cwnd += tc->snd_mss;
59  }
60  else if (ack_type == TCP_CC_PARTIALACK)
61  {
62  /* RFC 6582 Sec. 3.2 */
63  if (!tcp_opts_sack_permitted (&tc->rcv_opts))
64  {
65  /* Deflate the congestion window by the amount of new data
66  * acknowledged by the Cumulative Acknowledgment field.
67  * If the partial ACK acknowledges at least one SMSS of new data,
68  * then add back SMSS bytes to the congestion window. This
69  * artificially inflates the congestion window in order to reflect
70  * the additional segment that has left the network. This "partial
71  * window deflation" attempts to ensure that, when fast recovery
72  * eventually ends, approximately ssthresh amount of data will be
73  * outstanding in the network.*/
74  tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
75  tc->cwnd - tc->bytes_acked : tc->snd_mss;
76  if (tc->bytes_acked > tc->snd_mss)
77  tc->cwnd += tc->snd_mss;
78  }
79  }
80 }
81 
82 void
84 {
85  tc->ssthresh = tc->snd_wnd;
86  tc->cwnd = tcp_initial_cwnd (tc);
87 }
88 
90  .congestion = newreno_congestion,
91  .recovered = newreno_recovered,
92  .rcv_ack = newreno_rcv_ack,
93  .rcv_cong_ack = newreno_rcv_cong_ack,
94  .init = newreno_conn_init
95 };
96 
99 {
100  clib_error_t *error = 0;
101 
103 
104  return error;
105 }
106 
108 
109 /*
110  * fd.io coding-style-patch-verification: ON
111  *
112  * Local Variables:
113  * eval: (c-set-style "gnu")
114  * End:
115  */
#define clib_min(x, y)
Definition: clib.h:291
void newreno_recovered(tcp_connection_t *tc)
Definition: tcp_newreno.c:25
struct _tcp_connection tcp_connection_t
void newreno_conn_init(tcp_connection_t *tc)
Definition: tcp_newreno.c:83
#define VLIB_INIT_FUNCTION(x)
Definition: init.h:163
#define tcp_in_slowstart(tc)
Definition: tcp.h:345
unsigned int u32
Definition: types.h:88
void newreno_rcv_ack(tcp_connection_t *tc)
Definition: tcp_newreno.c:31
static u32 tcp_flight_size(const tcp_connection_t *tc)
Our estimate of the number of bytes in flight (pipe size)
Definition: tcp.h:580
enum _tcp_cc_ack_t tcp_cc_ack_t
vlib_main_t * vm
Definition: buffer.c:294
clib_error_t * newreno_init(vlib_main_t *vm)
Definition: tcp_newreno.c:98
void newreno_rcv_cong_ack(tcp_connection_t *tc, tcp_cc_ack_t ack_type)
Definition: tcp_newreno.c:53
void tcp_cc_algo_register(tcp_cc_algorithm_type_e type, const tcp_cc_algorithm_t *vft)
Definition: tcp.c:518
struct _tcp_cc_algorithm tcp_cc_algorithm_t
Definition: tcp.h:252
#define clib_max(x, y)
Definition: clib.h:284
static u32 tcp_initial_cwnd(const tcp_connection_t *tc)
Initial cwnd as per RFC5681.
Definition: tcp.h:605
static const tcp_cc_algorithm_t tcp_newreno
Definition: tcp_newreno.c:89
void newreno_congestion(tcp_connection_t *tc)
Definition: tcp_newreno.c:19
#define tcp_opts_sack_permitted(_to)
Definition: tcp_packet.h:160
static u32 transport_tx_fifo_size(transport_connection_t *tc)
Definition: session.h:491