FD.io VPP  v18.01.2-1-g9b554f3
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  /* Round up to 1 if needed */
40  tc->cwnd += clib_max ((tc->snd_mss * tc->snd_mss) / tc->cwnd, 1);
41  }
42 }
43 
44 void
46 {
47  if (ack_type == TCP_CC_DUPACK)
48  {
49  if (!tcp_opts_sack_permitted (tc))
50  tc->cwnd += tc->snd_mss;
51  }
52  else if (ack_type == TCP_CC_PARTIALACK)
53  {
54  /* RFC 6582 Sec. 3.2 */
55  if (!tcp_opts_sack_permitted (&tc->rcv_opts))
56  {
57  /* Deflate the congestion window by the amount of new data
58  * acknowledged by the Cumulative Acknowledgment field.
59  * If the partial ACK acknowledges at least one SMSS of new data,
60  * then add back SMSS bytes to the congestion window. This
61  * artificially inflates the congestion window in order to reflect
62  * the additional segment that has left the network. This "partial
63  * window deflation" attempts to ensure that, when fast recovery
64  * eventually ends, approximately ssthresh amount of data will be
65  * outstanding in the network.*/
66  tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
67  tc->cwnd - tc->bytes_acked : tc->snd_mss;
68  if (tc->bytes_acked > tc->snd_mss)
69  tc->cwnd += tc->snd_mss;
70  }
71  }
72 }
73 
74 void
76 {
77  tc->ssthresh = tc->snd_wnd;
78  tc->cwnd = tcp_initial_cwnd (tc);
79 }
80 
82  .congestion = newreno_congestion,
83  .recovered = newreno_recovered,
84  .rcv_ack = newreno_rcv_ack,
85  .rcv_cong_ack = newreno_rcv_cong_ack,
86  .init = newreno_conn_init
87 };
88 
91 {
92  clib_error_t *error = 0;
93 
95 
96  return error;
97 }
98 
100 
101 /*
102  * fd.io coding-style-patch-verification: ON
103  *
104  * Local Variables:
105  * eval: (c-set-style "gnu")
106  * End:
107  */
#define clib_min(x, y)
Definition: clib.h:340
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:75
#define VLIB_INIT_FUNCTION(x)
Definition: init.h:111
#define tcp_in_slowstart(tc)
Definition: tcp.h:325
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:556
enum _tcp_cc_ack_t tcp_cc_ack_t
vlib_main_t * vm
Definition: buffer.c:283
clib_error_t * newreno_init(vlib_main_t *vm)
Definition: tcp_newreno.c:90
void newreno_rcv_cong_ack(tcp_connection_t *tc, tcp_cc_ack_t ack_type)
Definition: tcp_newreno.c:45
struct _tcp_cc_algorithm tcp_cc_algorithm_t
Definition: tcp.h:234
#define clib_max(x, y)
Definition: clib.h:333
static u32 tcp_initial_cwnd(const tcp_connection_t *tc)
Initial cwnd as per RFC5681.
Definition: tcp.h:581
static const tcp_cc_algorithm_t tcp_newreno
Definition: tcp_newreno.c:81
static void tcp_cc_algo_register(tcp_cc_algorithm_type_e type, const tcp_cc_algorithm_t *vft)
Definition: tcp.h:888
void newreno_congestion(tcp_connection_t *tc)
Definition: tcp_newreno.c:19
#define tcp_opts_sack_permitted(_to)
Definition: tcp_packet.h:160