Line data    Source code

       1             : /*
       2             :  * Copyright (c) 2017-2019 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             : #include <vnet/tcp/tcp_inlines.h>
      18             : 
      19             : typedef struct nwreno_cfg_
      20             : {
      21             :   u32 ssthresh;
      22             : } newreno_cfg_t;
      23             : 
      24             : static newreno_cfg_t newreno_cfg = {
      25             :   .ssthresh = 0x7FFFFFFFU,
      26             : };
      27             : 
      28             : static void
      29           0 : newreno_congestion (tcp_connection_t * tc)
      30             : {
      31           0 :   tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss);
      32           0 :   tc->cwnd = tc->ssthresh;
      33           0 : }
      34             : 
      35             : static void
      36           0 : newreno_loss (tcp_connection_t * tc)
      37             : {
      38           0 :   tc->cwnd = tcp_loss_wnd (tc);
      39           0 : }
      40             : 
      41             : static void
      42           0 : newreno_recovered (tcp_connection_t * tc)
      43             : {
      44           0 :   tc->cwnd = tc->ssthresh;
      45           0 : }
      46             : 
      47             : static void
      48           0 : newreno_rcv_ack (tcp_connection_t * tc, tcp_rate_sample_t * rs)
      49             : {
      50           0 :   if (tcp_in_slowstart (tc))
      51             :     {
      52           0 :       tc->cwnd += clib_min (tc->snd_mss, rs->delivered);
      53             :     }
      54             :   else
      55             :     {
      56             :       /* tc->cwnd += clib_max ((tc->snd_mss * tc->snd_mss) / tc->cwnd, 1); */
      57           0 :       tcp_cwnd_accumulate (tc, tc->cwnd, rs->delivered);
      58             :     }
      59           0 : }
      60             : 
      61             : void
      62           0 : newreno_rcv_cong_ack (tcp_connection_t * tc, tcp_cc_ack_t ack_type,
      63             :                       tcp_rate_sample_t * rs)
      64             : {
      65             :   /* With sacks prr controls the data in flight post congestion */
      66           0 :   if (PREDICT_TRUE (tcp_opts_sack_permitted (tc)))
      67           0 :     return;
      68             : 
      69           0 :   if (ack_type == TCP_CC_DUPACK)
      70             :     {
      71           0 :       tc->cwnd += tc->snd_mss;
      72             :     }
      73           0 :   else if (ack_type == TCP_CC_PARTIALACK)
      74             :     {
      75             :       /* RFC 6582 Sec. 3.2
      76             :        * Deflate the congestion window by the amount of new data
      77             :        * acknowledged by the Cumulative Acknowledgment field.
      78             :        * If the partial ACK acknowledges at least one SMSS of new data,
      79             :        * then add back SMSS bytes to the congestion window. This
      80             :        * artificially inflates the congestion window in order to reflect
      81             :        * the additional segment that has left the network. This "partial
      82             :        * window deflation" attempts to ensure that, when fast recovery
      83             :        * eventually ends, approximately ssthresh amount of data will be
      84             :        * outstanding in the network. */
      85           0 :       tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ?
      86           0 :                    tc->cwnd - tc->bytes_acked :
      87           0 :                    tc->snd_mss;
      88           0 :       if (tc->bytes_acked > tc->snd_mss)
      89           0 :         tc->cwnd += tc->snd_mss;
      90             :     }
      91             : }
      92             : 
      93             : static void
      94           0 : newreno_conn_init (tcp_connection_t * tc)
      95             : {
      96           0 :   tc->ssthresh = newreno_cfg.ssthresh;
      97           0 :   tc->cwnd = tcp_initial_cwnd (tc);
      98           0 : }
      99             : 
     100             : static uword
     101           0 : newreno_unformat_config (unformat_input_t * input)
     102             : {
     103           0 :   u32 ssthresh = 0x7FFFFFFFU;
     104             : 
     105           0 :   if (!input)
     106           0 :     return 0;
     107             : 
     108           0 :   unformat_skip_white_space (input);
     109             : 
     110           0 :   while (unformat_check_input (input) != UNFORMAT_END_OF_INPUT)
     111             :     {
     112           0 :       if (unformat (input, "ssthresh %u", &ssthresh))
     113           0 :         newreno_cfg.ssthresh = ssthresh;
     114             :       else
     115           0 :         return 0;
     116             :     }
     117           0 :   return 1;
     118             : }
     119             : 
     120             : const static tcp_cc_algorithm_t tcp_newreno = {
     121             :   .name = "newreno",
     122             :   .unformat_cfg = newreno_unformat_config,
     123             :   .congestion = newreno_congestion,
     124             :   .loss = newreno_loss,
     125             :   .recovered = newreno_recovered,
     126             :   .rcv_ack = newreno_rcv_ack,
     127             :   .rcv_cong_ack = newreno_rcv_cong_ack,
     128             :   .init = newreno_conn_init
     129             : };
     130             : 
     131             : clib_error_t *
     132         575 : newreno_init (vlib_main_t * vm)
     133             : {
     134         575 :   clib_error_t *error = 0;
     135             : 
     136         575 :   tcp_cc_algo_register (TCP_CC_NEWRENO, &tcp_newreno);
     137             : 
     138         575 :   return error;
     139             : }
     140             : 
     141       58751 : VLIB_INIT_FUNCTION (newreno_init);
     142             : 
     143             : /*
     144             :  * fd.io coding-style-patch-verification: ON
     145             :  *
     146             :  * Local Variables:
     147             :  * eval: (c-set-style "gnu")
     148             :  * End:
     149             :  */