/* * Copyright (c) 2017-2019 Cisco and/or its affiliates. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at: * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include <vnet/tcp/tcp.h> static void newreno_congestion (tcp_connection_t * tc) { tc->ssthresh = clib_max (tcp_flight_size (tc) / 2, 2 * tc->snd_mss); tc->cwnd = tc->ssthresh; } static void newreno_loss (tcp_connection_t * tc) { tc->cwnd = tcp_loss_wnd (tc); } static void newreno_recovered (tcp_connection_t * tc) { tc->cwnd = tc->ssthresh; } static void newreno_rcv_ack (tcp_connection_t * tc, tcp_rate_sample_t * rs) { if (tcp_in_slowstart (tc)) { tc->cwnd += clib_min (tc->snd_mss, tc->bytes_acked); } else { /* tc->cwnd += clib_max ((tc->snd_mss * tc->snd_mss) / tc->cwnd, 1); */ tcp_cwnd_accumulate (tc, tc->cwnd, tc->bytes_acked); } } void newreno_rcv_cong_ack (tcp_connection_t * tc, tcp_cc_ack_t ack_type, tcp_rate_sample_t * rs) { if (ack_type == TCP_CC_DUPACK) { if (!tcp_opts_sack_permitted (tc)) tc->cwnd += tc->snd_mss; } else if (ack_type == TCP_CC_PARTIALACK) { /* RFC 6582 Sec. 3.2 */ if (!tcp_opts_sack_permitted (&tc->rcv_opts)) { /* Deflate the congestion window by the amount of new data * acknowledged by the Cumulative Acknowledgment field. * If the partial ACK acknowledges at least one SMSS of new data, * then add back SMSS bytes to the congestion window. This * artificially inflates the congestion window in order to reflect * the additional segment that has left the network. This "partial * window deflation" attempts to ensure that, when fast recovery * eventually ends, approximately ssthresh amount of data will be * outstanding in the network.*/ tc->cwnd = (tc->cwnd > tc->bytes_acked + tc->snd_mss) ? tc->cwnd - tc->bytes_acked : tc->snd_mss; if (tc->bytes_acked > tc->snd_mss) tc->cwnd += tc->snd_mss; } } } static void newreno_conn_init (tcp_connection_t * tc) { tc->ssthresh = tc->snd_wnd; tc->cwnd = tcp_initial_cwnd (tc); } const static tcp_cc_algorithm_t tcp_newreno = { .name = "newreno", .congestion = newreno_congestion, .loss = newreno_loss, .recovered = newreno_recovered, .rcv_ack = newreno_rcv_ack, .rcv_cong_ack = newreno_rcv_cong_ack, .init = newreno_conn_init }; clib_error_t * newreno_init (vlib_main_t * vm) { clib_error_t *error = 0; tcp_cc_algo_register (TCP_CC_NEWRENO, &tcp_newreno); return error; } VLIB_INIT_FUNCTION (newreno_init); /* * fd.io coding-style-patch-verification: ON * * Local Variables: * eval: (c-set-style "gnu") * End: */