1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 1982, 1986, 1988, 1990, 1993, 1994, 1995 5 * The Regents of the University of California. 6 * Copyright (c) 2007-2008,2010,2014 7 * Swinburne University of Technology, Melbourne, Australia. 8 * Copyright (c) 2009-2010 Lawrence Stewart <lstewart@freebsd.org> 9 * Copyright (c) 2010 The FreeBSD Foundation 10 * All rights reserved. 11 * 12 * This software was developed at the Centre for Advanced Internet 13 * Architectures, Swinburne University of Technology, by Lawrence Stewart, James 14 * Healy and David Hayes, made possible in part by a grant from the Cisco 15 * University Research Program Fund at Community Foundation Silicon Valley. 16 * 17 * Portions of this software were developed at the Centre for Advanced 18 * Internet Architectures, Swinburne University of Technology, Melbourne, 19 * Australia by David Hayes under sponsorship from the FreeBSD Foundation. 20 * 21 * Redistribution and use in source and binary forms, with or without 22 * modification, are permitted provided that the following conditions 23 * are met: 24 * 1. Redistributions of source code must retain the above copyright 25 * notice, this list of conditions and the following disclaimer. 26 * 2. Redistributions in binary form must reproduce the above copyright 27 * notice, this list of conditions and the following disclaimer in the 28 * documentation and/or other materials provided with the distribution. 29 * 30 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 31 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 32 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 33 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 34 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 35 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 36 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 37 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 38 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 39 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 40 * SUCH DAMAGE. 41 */ 42 43 /* 44 * This software was first released in 2007 by James Healy and Lawrence Stewart 45 * whilst working on the NewTCP research project at Swinburne University of 46 * Technology's Centre for Advanced Internet Architectures, Melbourne, 47 * Australia, which was made possible in part by a grant from the Cisco 48 * University Research Program Fund at Community Foundation Silicon Valley. 49 * More details are available at: 50 * http://caia.swin.edu.au/urp/newtcp/ 51 * 52 * Dec 2014 garmitage@swin.edu.au 53 * Borrowed code fragments from cc_cdg.c to add modifiable beta 54 * via sysctls. 55 * 56 */ 57 58 #include <sys/cdefs.h> 59 __FBSDID("$FreeBSD$"); 60 61 #include <sys/param.h> 62 #include <sys/kernel.h> 63 #include <sys/malloc.h> 64 #include <sys/module.h> 65 #include <sys/socket.h> 66 #include <sys/lock.h> 67 #include <sys/mutex.h> 68 #include <sys/socketvar.h> 69 #include <sys/sysctl.h> 70 #include <sys/systm.h> 71 72 #include <net/vnet.h> 73 74 #include <net/route.h> 75 #include <net/route/nhop.h> 76 77 #include <netinet/in_pcb.h> 78 #include <netinet/in.h> 79 #include <netinet/in_pcb.h> 80 #include <netinet/tcp.h> 81 #include <netinet/tcp_seq.h> 82 #include <netinet/tcp_var.h> 83 #include <netinet/tcp_log_buf.h> 84 #include <netinet/tcp_hpts.h> 85 #include <netinet/cc/cc.h> 86 #include <netinet/cc/cc_module.h> 87 #include <netinet/cc/cc_newreno.h> 88 89 static void newreno_cb_destroy(struct cc_var *ccv); 90 static void newreno_ack_received(struct cc_var *ccv, uint16_t type); 91 static void newreno_after_idle(struct cc_var *ccv); 92 static void newreno_cong_signal(struct cc_var *ccv, uint32_t type); 93 static int newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf); 94 static void newreno_newround(struct cc_var *ccv, uint32_t round_cnt); 95 static void newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas); 96 static int newreno_cb_init(struct cc_var *ccv, void *); 97 static size_t newreno_data_sz(void); 98 99 100 VNET_DECLARE(uint32_t, newreno_beta); 101 #define V_newreno_beta VNET(newreno_beta) 102 VNET_DEFINE(uint32_t, newreno_beta_ecn) = 80; 103 #define V_newreno_beta_ecn VNET(newreno_beta_ecn) 104 105 struct cc_algo newreno_cc_algo = { 106 .name = "newreno", 107 .cb_destroy = newreno_cb_destroy, 108 .ack_received = newreno_ack_received, 109 .after_idle = newreno_after_idle, 110 .cong_signal = newreno_cong_signal, 111 .post_recovery = newreno_cc_post_recovery, 112 .ctl_output = newreno_ctl_output, 113 .newround = newreno_newround, 114 .rttsample = newreno_rttsample, 115 .cb_init = newreno_cb_init, 116 .cc_data_sz = newreno_data_sz, 117 }; 118 119 static uint32_t hystart_lowcwnd = 16; 120 static uint32_t hystart_minrtt_thresh = 4000; 121 static uint32_t hystart_maxrtt_thresh = 16000; 122 static uint32_t hystart_n_rttsamples = 8; 123 static uint32_t hystart_css_growth_div = 4; 124 static uint32_t hystart_css_rounds = 5; 125 static uint32_t hystart_bblogs = 0; 126 127 static void 128 newreno_log_hystart_event(struct cc_var *ccv, struct newreno *nreno, uint8_t mod, uint32_t flex1) 129 { 130 /* 131 * Types of logs (mod value) 132 * 1 - rtt_thresh in flex1, checking to see if RTT is to great. 133 * 2 - rtt is too great, rtt_thresh in flex1. 134 * 3 - CSS is active incr in flex1 135 * 4 - A new round is beginning flex1 is round count 136 * 5 - A new RTT measurement flex1 is the new measurement. 137 * 6 - We enter CA ssthresh is also in flex1. 138 * 7 - Socket option to change hystart executed opt.val in flex1. 139 * 8 - Back out of CSS into SS, flex1 is the css_baseline_minrtt 140 */ 141 struct tcpcb *tp; 142 143 if (hystart_bblogs == 0) 144 return; 145 tp = ccv->ccvc.tcp; 146 if (tp->t_logstate != TCP_LOG_STATE_OFF) { 147 union tcp_log_stackspecific log; 148 struct timeval tv; 149 150 memset(&log, 0, sizeof(log)); 151 log.u_bbr.flex1 = flex1; 152 log.u_bbr.flex2 = nreno->css_current_round_minrtt; 153 log.u_bbr.flex3 = nreno->css_lastround_minrtt; 154 log.u_bbr.flex4 = nreno->css_rttsample_count; 155 log.u_bbr.flex5 = nreno->css_entered_at_round; 156 log.u_bbr.flex6 = nreno->css_baseline_minrtt; 157 /* We only need bottom 16 bits of flags */ 158 log.u_bbr.flex7 = nreno->newreno_flags & 0x0000ffff; 159 log.u_bbr.flex8 = mod; 160 log.u_bbr.epoch = nreno->css_current_round; 161 log.u_bbr.timeStamp = tcp_get_usecs(&tv); 162 log.u_bbr.lt_epoch = nreno->css_fas_at_css_entry; 163 log.u_bbr.pkts_out = nreno->css_last_fas; 164 log.u_bbr.delivered = nreno->css_lowrtt_fas; 165 TCP_LOG_EVENTP(tp, NULL, 166 &tp->t_inpcb->inp_socket->so_rcv, 167 &tp->t_inpcb->inp_socket->so_snd, 168 TCP_HYSTART, 0, 169 0, &log, false, &tv); 170 } 171 } 172 173 static size_t 174 newreno_data_sz(void) 175 { 176 return (sizeof(struct newreno)); 177 } 178 179 static int 180 newreno_cb_init(struct cc_var *ccv, void *ptr) 181 { 182 struct newreno *nreno; 183 184 INP_WLOCK_ASSERT(ccv->ccvc.tcp->t_inpcb); 185 if (ptr == NULL) { 186 ccv->cc_data = malloc(sizeof(struct newreno), M_CC_MEM, M_NOWAIT); 187 if (ccv->cc_data == NULL) 188 return (ENOMEM); 189 } else 190 ccv->cc_data = ptr; 191 nreno = (struct newreno *)ccv->cc_data; 192 /* NB: nreno is not zeroed, so initialise all fields. */ 193 nreno->beta = V_newreno_beta; 194 nreno->beta_ecn = V_newreno_beta_ecn; 195 /* 196 * We set the enabled flag so that if 197 * the socket option gets strobed and 198 * we have not hit a loss 199 */ 200 nreno->newreno_flags = CC_NEWRENO_HYSTART_ENABLED; 201 /* At init set both to infinity */ 202 nreno->css_lastround_minrtt = 0xffffffff; 203 nreno->css_current_round_minrtt = 0xffffffff; 204 nreno->css_current_round = 0; 205 nreno->css_baseline_minrtt = 0xffffffff; 206 nreno->css_rttsample_count = 0; 207 nreno->css_entered_at_round = 0; 208 nreno->css_fas_at_css_entry = 0; 209 nreno->css_lowrtt_fas = 0; 210 nreno->css_last_fas = 0; 211 return (0); 212 } 213 214 static void 215 newreno_cb_destroy(struct cc_var *ccv) 216 { 217 free(ccv->cc_data, M_CC_MEM); 218 } 219 220 static void 221 newreno_ack_received(struct cc_var *ccv, uint16_t type) 222 { 223 struct newreno *nreno; 224 225 nreno = ccv->cc_data; 226 if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && 227 (ccv->flags & CCF_CWND_LIMITED)) { 228 u_int cw = CCV(ccv, snd_cwnd); 229 u_int incr = CCV(ccv, t_maxseg); 230 231 /* 232 * Regular in-order ACK, open the congestion window. 233 * Method depends on which congestion control state we're 234 * in (slow start or cong avoid) and if ABC (RFC 3465) is 235 * enabled. 236 * 237 * slow start: cwnd <= ssthresh 238 * cong avoid: cwnd > ssthresh 239 * 240 * slow start and ABC (RFC 3465): 241 * Grow cwnd exponentially by the amount of data 242 * ACKed capping the max increment per ACK to 243 * (abc_l_var * maxseg) bytes. 244 * 245 * slow start without ABC (RFC 5681): 246 * Grow cwnd exponentially by maxseg per ACK. 247 * 248 * cong avoid and ABC (RFC 3465): 249 * Grow cwnd linearly by maxseg per RTT for each 250 * cwnd worth of ACKed data. 251 * 252 * cong avoid without ABC (RFC 5681): 253 * Grow cwnd linearly by approximately maxseg per RTT using 254 * maxseg^2 / cwnd per ACK as the increment. 255 * If cwnd > maxseg^2, fix the cwnd increment at 1 byte to 256 * avoid capping cwnd. 257 */ 258 if (cw > CCV(ccv, snd_ssthresh)) { 259 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 260 /* 261 * We have slipped into CA with 262 * CSS active. Deactivate all. 263 */ 264 /* Turn off the CSS flag */ 265 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 266 /* Disable use of CSS in the future except long idle */ 267 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 268 } 269 if (V_tcp_do_rfc3465) { 270 if (ccv->flags & CCF_ABC_SENTAWND) 271 ccv->flags &= ~CCF_ABC_SENTAWND; 272 else 273 incr = 0; 274 } else 275 incr = max((incr * incr / cw), 1); 276 } else if (V_tcp_do_rfc3465) { 277 /* 278 * In slow-start with ABC enabled and no RTO in sight? 279 * (Must not use abc_l_var > 1 if slow starting after 280 * an RTO. On RTO, snd_nxt = snd_una, so the 281 * snd_nxt == snd_max check is sufficient to 282 * handle this). 283 * 284 * XXXLAS: Find a way to signal SS after RTO that 285 * doesn't rely on tcpcb vars. 286 */ 287 uint16_t abc_val; 288 289 if (ccv->flags & CCF_USE_LOCAL_ABC) 290 abc_val = ccv->labc; 291 else 292 abc_val = V_tcp_abc_l_var; 293 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ALLOWED) && 294 (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) && 295 ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) { 296 /* 297 * Hystart is allowed and still enabled and we are not yet 298 * in CSS. Lets check to see if we can make a decision on 299 * if we need to go into CSS. 300 */ 301 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 302 (CCV(ccv, snd_cwnd) > 303 (hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp)))) { 304 uint32_t rtt_thresh; 305 306 /* Clamp (minrtt_thresh, lastround/8, maxrtt_thresh) */ 307 rtt_thresh = (nreno->css_lastround_minrtt >> 3); 308 if (rtt_thresh < hystart_minrtt_thresh) 309 rtt_thresh = hystart_minrtt_thresh; 310 if (rtt_thresh > hystart_maxrtt_thresh) 311 rtt_thresh = hystart_maxrtt_thresh; 312 newreno_log_hystart_event(ccv, nreno, 1, rtt_thresh); 313 if (nreno->css_current_round_minrtt >= (nreno->css_lastround_minrtt + rtt_thresh)) { 314 /* Enter CSS */ 315 nreno->newreno_flags |= CC_NEWRENO_HYSTART_IN_CSS; 316 nreno->css_fas_at_css_entry = nreno->css_lowrtt_fas; 317 nreno->css_baseline_minrtt = nreno->css_current_round_minrtt; 318 nreno->css_entered_at_round = nreno->css_current_round; 319 newreno_log_hystart_event(ccv, nreno, 2, rtt_thresh); 320 } 321 } 322 } 323 if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) 324 incr = min(ccv->bytes_this_ack, 325 ccv->nsegs * abc_val * 326 CCV(ccv, t_maxseg)); 327 else 328 incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); 329 330 /* Only if Hystart is enabled will the flag get set */ 331 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 332 incr /= hystart_css_growth_div; 333 newreno_log_hystart_event(ccv, nreno, 3, incr); 334 } 335 } 336 /* ABC is on by default, so incr equals 0 frequently. */ 337 if (incr > 0) 338 CCV(ccv, snd_cwnd) = min(cw + incr, 339 TCP_MAXWIN << CCV(ccv, snd_scale)); 340 } 341 } 342 343 static void 344 newreno_after_idle(struct cc_var *ccv) 345 { 346 struct newreno *nreno; 347 348 nreno = ccv->cc_data; 349 newreno_cc_after_idle(ccv); 350 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) { 351 if (CCV(ccv, snd_cwnd) <= (hystart_lowcwnd * tcp_fixed_maxseg(ccv->ccvc.tcp))) { 352 /* 353 * Re-enable hystart if our cwnd has fallen below 354 * the hystart lowcwnd point. 355 */ 356 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 357 nreno->newreno_flags |= CC_NEWRENO_HYSTART_ENABLED; 358 } 359 } 360 } 361 362 /* 363 * Perform any necessary tasks before we enter congestion recovery. 364 */ 365 static void 366 newreno_cong_signal(struct cc_var *ccv, uint32_t type) 367 { 368 struct newreno *nreno; 369 uint32_t beta, beta_ecn, cwin, factor; 370 u_int mss; 371 372 cwin = CCV(ccv, snd_cwnd); 373 mss = tcp_fixed_maxseg(ccv->ccvc.tcp); 374 nreno = ccv->cc_data; 375 beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;; 376 beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn; 377 /* 378 * Note that we only change the backoff for ECN if the 379 * global sysctl V_cc_do_abe is set <or> the stack itself 380 * has set a flag in our newreno_flags (due to pacing) telling 381 * us to use the lower valued back-off. 382 */ 383 if ((type == CC_ECN) && 384 (V_cc_do_abe || 385 ((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN_ENABLED)))) 386 factor = beta_ecn; 387 else 388 factor = beta; 389 390 /* Catch algos which mistakenly leak private signal types. */ 391 KASSERT((type & CC_SIGPRIVMASK) == 0, 392 ("%s: congestion signal type 0x%08x is private\n", __func__, type)); 393 394 cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss), 395 2) * mss; 396 397 switch (type) { 398 case CC_NDUPACK: 399 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 400 /* Make sure the flags are all off we had a loss */ 401 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 402 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 403 } 404 if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { 405 if (IN_CONGRECOVERY(CCV(ccv, t_flags) && 406 V_cc_do_abe && V_cc_abe_frlossreduce)) { 407 CCV(ccv, snd_ssthresh) = 408 ((uint64_t)CCV(ccv, snd_ssthresh) * 409 (uint64_t)beta) / (uint64_t)beta_ecn; 410 } 411 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) 412 CCV(ccv, snd_ssthresh) = cwin; 413 ENTER_RECOVERY(CCV(ccv, t_flags)); 414 } 415 break; 416 case CC_ECN: 417 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 418 /* Make sure the flags are all off we had a loss */ 419 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 420 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 421 } 422 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { 423 CCV(ccv, snd_ssthresh) = cwin; 424 CCV(ccv, snd_cwnd) = cwin; 425 ENTER_CONGRECOVERY(CCV(ccv, t_flags)); 426 } 427 break; 428 case CC_RTO: 429 CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd), 430 CCV(ccv, snd_cwnd)) / 2 / mss, 431 2) * mss; 432 CCV(ccv, snd_cwnd) = mss; 433 break; 434 } 435 } 436 437 static int 438 newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf) 439 { 440 struct newreno *nreno; 441 struct cc_newreno_opts *opt; 442 443 if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts)) 444 return (EMSGSIZE); 445 446 if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo) 447 return (ENOPROTOOPT); 448 449 nreno = (struct newreno *)ccv->cc_data; 450 opt = buf; 451 switch (sopt->sopt_dir) { 452 case SOPT_SET: 453 switch (opt->name) { 454 case CC_NEWRENO_BETA: 455 nreno->beta = opt->val; 456 break; 457 case CC_NEWRENO_BETA_ECN: 458 if ((!V_cc_do_abe) && ((nreno->newreno_flags & CC_NEWRENO_BETA_ECN) == 0)) 459 return (EACCES); 460 nreno->beta_ecn = opt->val; 461 nreno->newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED; 462 break; 463 case CC_NEWRENO_ENABLE_HYSTART: 464 /* Allow hystart on this connection */ 465 if (opt->val != 0) { 466 nreno->newreno_flags |= CC_NEWRENO_HYSTART_ALLOWED; 467 if (opt->val > 1) 468 nreno->newreno_flags |= CC_NEWRENO_HYSTART_CAN_SH_CWND; 469 if (opt->val > 2) 470 nreno->newreno_flags |= CC_NEWRENO_HYSTART_CONS_SSTH; 471 } else 472 nreno->newreno_flags &= ~(CC_NEWRENO_HYSTART_ALLOWED|CC_NEWRENO_HYSTART_CAN_SH_CWND|CC_NEWRENO_HYSTART_CONS_SSTH); 473 newreno_log_hystart_event(ccv, nreno, 7, opt->val); 474 break; 475 default: 476 return (ENOPROTOOPT); 477 } 478 break; 479 case SOPT_GET: 480 switch (opt->name) { 481 case CC_NEWRENO_BETA: 482 opt->val = (nreno == NULL) ? 483 V_newreno_beta : nreno->beta; 484 break; 485 case CC_NEWRENO_BETA_ECN: 486 opt->val = (nreno == NULL) ? 487 V_newreno_beta_ecn : nreno->beta_ecn; 488 break; 489 case CC_NEWRENO_ENABLE_HYSTART: 490 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ALLOWED) { 491 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_CONS_SSTH) 492 opt->val = 3; 493 else if (nreno->newreno_flags & CC_NEWRENO_HYSTART_CAN_SH_CWND) 494 opt->val = 2; 495 else 496 opt->val = 1; 497 } else 498 opt->val = 0; 499 break; 500 default: 501 return (ENOPROTOOPT); 502 } 503 break; 504 default: 505 return (EINVAL); 506 } 507 508 return (0); 509 } 510 511 static int 512 newreno_beta_handler(SYSCTL_HANDLER_ARGS) 513 { 514 int error; 515 uint32_t new; 516 517 new = *(uint32_t *)arg1; 518 error = sysctl_handle_int(oidp, &new, 0, req); 519 if (error == 0 && req->newptr != NULL ) { 520 if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe) 521 error = EACCES; 522 else if (new == 0 || new > 100) 523 error = EINVAL; 524 else 525 *(uint32_t *)arg1 = new; 526 } 527 528 return (error); 529 } 530 531 static void 532 newreno_newround(struct cc_var *ccv, uint32_t round_cnt) 533 { 534 struct newreno *nreno; 535 536 nreno = (struct newreno *)ccv->cc_data; 537 /* We have entered a new round */ 538 nreno->css_lastround_minrtt = nreno->css_current_round_minrtt; 539 nreno->css_current_round_minrtt = 0xffffffff; 540 nreno->css_rttsample_count = 0; 541 nreno->css_current_round = round_cnt; 542 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) && 543 ((round_cnt - nreno->css_entered_at_round) >= hystart_css_rounds)) { 544 /* Enter CA */ 545 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_CAN_SH_CWND) { 546 /* 547 * We engage more than snd_ssthresh, engage 548 * the brakes!! Though we will stay in SS to 549 * creep back up again, so lets leave CSS active 550 * and give us hystart_css_rounds more rounds. 551 */ 552 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_CONS_SSTH) { 553 CCV(ccv, snd_ssthresh) = ((nreno->css_lowrtt_fas + nreno->css_fas_at_css_entry) / 2); 554 } else { 555 CCV(ccv, snd_ssthresh) = nreno->css_lowrtt_fas; 556 } 557 CCV(ccv, snd_cwnd) = nreno->css_fas_at_css_entry; 558 nreno->css_entered_at_round = round_cnt; 559 } else { 560 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); 561 /* Turn off the CSS flag */ 562 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 563 /* Disable use of CSS in the future except long idle */ 564 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 565 } 566 newreno_log_hystart_event(ccv, nreno, 6, CCV(ccv, snd_ssthresh)); 567 } 568 newreno_log_hystart_event(ccv, nreno, 4, round_cnt); 569 } 570 571 static void 572 newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas) 573 { 574 struct newreno *nreno; 575 576 nreno = (struct newreno *)ccv->cc_data; 577 if (rxtcnt > 1) { 578 /* 579 * Only look at RTT's that are non-ambiguous. 580 */ 581 return; 582 } 583 nreno->css_rttsample_count++; 584 nreno->css_last_fas = fas; 585 if (nreno->css_current_round_minrtt > usec_rtt) { 586 nreno->css_current_round_minrtt = usec_rtt; 587 nreno->css_lowrtt_fas = nreno->css_last_fas; 588 } 589 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) && 590 (nreno->css_rttsample_count >= hystart_n_rttsamples) && 591 (nreno->css_baseline_minrtt > nreno->css_current_round_minrtt)) { 592 /* 593 * We were in CSS and the RTT is now less, we 594 * entered CSS erroneously. 595 */ 596 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 597 newreno_log_hystart_event(ccv, nreno, 8, nreno->css_baseline_minrtt); 598 nreno->css_baseline_minrtt = 0xffffffff; 599 } 600 newreno_log_hystart_event(ccv, nreno, 5, usec_rtt); 601 } 602 603 SYSCTL_DECL(_net_inet_tcp_cc_newreno); 604 SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno, 605 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 606 "New Reno related settings"); 607 608 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta, 609 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 610 &VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU", 611 "New Reno beta, specified as number between 1 and 100"); 612 613 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn, 614 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 615 &VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU", 616 "New Reno beta ecn, specified as number between 1 and 100"); 617 618 SYSCTL_NODE(_net_inet_tcp_cc_newreno, OID_AUTO, hystartplusplus, 619 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 620 "New Reno related HyStart++ settings"); 621 622 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, lowcwnd, 623 CTLFLAG_RW, 624 &hystart_lowcwnd, 16, 625 "The number of MSS in the CWND before HyStart++ is active"); 626 627 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, minrtt_thresh, 628 CTLFLAG_RW, 629 &hystart_minrtt_thresh, 4000, 630 "HyStarts++ minimum RTT thresh used in clamp (in microseconds)"); 631 632 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, maxrtt_thresh, 633 CTLFLAG_RW, 634 &hystart_maxrtt_thresh, 16000, 635 "HyStarts++ maximum RTT thresh used in clamp (in microseconds)"); 636 637 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, n_rttsamples, 638 CTLFLAG_RW, 639 &hystart_n_rttsamples, 8, 640 "The number of RTT samples that must be seen to consider HyStart++"); 641 642 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, css_growth_div, 643 CTLFLAG_RW, 644 &hystart_css_growth_div, 4, 645 "The divisor to the growth when in Hystart++ CSS"); 646 647 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, css_rounds, 648 CTLFLAG_RW, 649 &hystart_css_rounds, 5, 650 "The number of rounds HyStart++ lasts in CSS before falling to CA"); 651 652 SYSCTL_UINT(_net_inet_tcp_cc_newreno_hystartplusplus, OID_AUTO, bblogs, 653 CTLFLAG_RW, 654 &hystart_bblogs, 0, 655 "Do we enable HyStart++ Black Box logs to be generated if BB logging is on"); 656 657 658 DECLARE_CC_MODULE(newreno, &newreno_cc_algo); 659 MODULE_VERSION(newreno, 2); 660