Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)
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sys/netinet/cc/cc_newreno.c
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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_DECLARE(uint32_t, newreno_beta_ecn); 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 void 120 newreno_log_hystart_event(struct cc_var *ccv, struct newreno *nreno, uint8_t mod, uint32_t flex1) 121 { 122 /* 123 * Types of logs (mod value) 124 * 1 - rtt_thresh in flex1, checking to see if RTT is to great. 125 * 2 - rtt is too great, rtt_thresh in flex1. 126 * 3 - CSS is active incr in flex1 127 * 4 - A new round is beginning flex1 is round count 128 * 5 - A new RTT measurement flex1 is the new measurement. 129 * 6 - We enter CA ssthresh is also in flex1. 130 * 7 - Socket option to change hystart executed opt.val in flex1. 131 * 8 - Back out of CSS into SS, flex1 is the css_baseline_minrtt 132 * 9 - We enter CA, via an ECN mark. 133 * 10 - We enter CA, via a loss. 134 * 11 - We have slipped out of SS into CA via cwnd growth. 135 * 12 - After idle has re-enabled hystart++ 136 */ 137 struct tcpcb *tp; 138 139 if (hystart_bblogs == 0) 140 return; 141 tp = ccv->ccvc.tcp; 142 if (tp->t_logstate != TCP_LOG_STATE_OFF) { 143 union tcp_log_stackspecific log; 144 struct timeval tv; 145 146 memset(&log, 0, sizeof(log)); 147 log.u_bbr.flex1 = flex1; 148 log.u_bbr.flex2 = nreno->css_current_round_minrtt; 149 log.u_bbr.flex3 = nreno->css_lastround_minrtt; 150 log.u_bbr.flex4 = nreno->css_rttsample_count; 151 log.u_bbr.flex5 = nreno->css_entered_at_round; 152 log.u_bbr.flex6 = nreno->css_baseline_minrtt; 153 /* We only need bottom 16 bits of flags */ 154 log.u_bbr.flex7 = nreno->newreno_flags & 0x0000ffff; 155 log.u_bbr.flex8 = mod; 156 log.u_bbr.epoch = nreno->css_current_round; 157 log.u_bbr.timeStamp = tcp_get_usecs(&tv); 158 log.u_bbr.lt_epoch = nreno->css_fas_at_css_entry; 159 log.u_bbr.pkts_out = nreno->css_last_fas; 160 log.u_bbr.delivered = nreno->css_lowrtt_fas; 161 log.u_bbr.pkt_epoch = ccv->flags; 162 TCP_LOG_EVENTP(tp, NULL, 163 &tptosocket(tp)->so_rcv, 164 &tptosocket(tp)->so_snd, 165 TCP_HYSTART, 0, 166 0, &log, false, &tv); 167 } 168 } 169 170 static size_t 171 newreno_data_sz(void) 172 { 173 return (sizeof(struct newreno)); 174 } 175 176 static int 177 newreno_cb_init(struct cc_var *ccv, void *ptr) 178 { 179 struct newreno *nreno; 180 181 INP_WLOCK_ASSERT(tptoinpcb(ccv->ccvc.tcp)); 182 if (ptr == NULL) { 183 ccv->cc_data = malloc(sizeof(struct newreno), M_CC_MEM, M_NOWAIT); 184 if (ccv->cc_data == NULL) 185 return (ENOMEM); 186 } else 187 ccv->cc_data = ptr; 188 nreno = (struct newreno *)ccv->cc_data; 189 /* NB: nreno is not zeroed, so initialise all fields. */ 190 nreno->beta = V_newreno_beta; 191 nreno->beta_ecn = V_newreno_beta_ecn; 192 /* 193 * We set the enabled flag so that if 194 * the socket option gets strobed and 195 * we have not hit a loss 196 */ 197 nreno->newreno_flags = CC_NEWRENO_HYSTART_ENABLED; 198 /* At init set both to infinity */ 199 nreno->css_lastround_minrtt = 0xffffffff; 200 nreno->css_current_round_minrtt = 0xffffffff; 201 nreno->css_current_round = 0; 202 nreno->css_baseline_minrtt = 0xffffffff; 203 nreno->css_rttsample_count = 0; 204 nreno->css_entered_at_round = 0; 205 nreno->css_fas_at_css_entry = 0; 206 nreno->css_lowrtt_fas = 0; 207 nreno->css_last_fas = 0; 208 return (0); 209 } 210 211 static void 212 newreno_cb_destroy(struct cc_var *ccv) 213 { 214 free(ccv->cc_data, M_CC_MEM); 215 } 216 217 static void 218 newreno_ack_received(struct cc_var *ccv, uint16_t type) 219 { 220 struct newreno *nreno; 221 222 nreno = ccv->cc_data; 223 if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && 224 (ccv->flags & CCF_CWND_LIMITED)) { 225 u_int cw = CCV(ccv, snd_cwnd); 226 u_int incr = CCV(ccv, t_maxseg); 227 228 /* 229 * Regular in-order ACK, open the congestion window. 230 * Method depends on which congestion control state we're 231 * in (slow start or cong avoid) and if ABC (RFC 3465) is 232 * enabled. 233 * 234 * slow start: cwnd <= ssthresh 235 * cong avoid: cwnd > ssthresh 236 * 237 * slow start and ABC (RFC 3465): 238 * Grow cwnd exponentially by the amount of data 239 * ACKed capping the max increment per ACK to 240 * (abc_l_var * maxseg) bytes. 241 * 242 * slow start without ABC (RFC 5681): 243 * Grow cwnd exponentially by maxseg per ACK. 244 * 245 * cong avoid and ABC (RFC 3465): 246 * Grow cwnd linearly by maxseg per RTT for each 247 * cwnd worth of ACKed data. 248 * 249 * cong avoid without ABC (RFC 5681): 250 * Grow cwnd linearly by approximately maxseg per RTT using 251 * maxseg^2 / cwnd per ACK as the increment. 252 * If cwnd > maxseg^2, fix the cwnd increment at 1 byte to 253 * avoid capping cwnd. 254 */ 255 if (cw > CCV(ccv, snd_ssthresh)) { 256 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 257 /* 258 * We have slipped into CA with 259 * CSS active. Deactivate all. 260 */ 261 /* Turn off the CSS flag */ 262 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 263 /* Disable use of CSS in the future except long idle */ 264 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 265 newreno_log_hystart_event(ccv, nreno, 11, CCV(ccv, snd_ssthresh)); 266 } 267 if (V_tcp_do_rfc3465) { 268 if (ccv->flags & CCF_ABC_SENTAWND) 269 ccv->flags &= ~CCF_ABC_SENTAWND; 270 else 271 incr = 0; 272 } else 273 incr = max((incr * incr / cw), 1); 274 } else if (V_tcp_do_rfc3465) { 275 /* 276 * In slow-start with ABC enabled and no RTO in sight? 277 * (Must not use abc_l_var > 1 if slow starting after 278 * an RTO. On RTO, snd_nxt = snd_una, so the 279 * snd_nxt == snd_max check is sufficient to 280 * handle this). 281 * 282 * XXXLAS: Find a way to signal SS after RTO that 283 * doesn't rely on tcpcb vars. 284 */ 285 uint16_t abc_val; 286 287 if (ccv->flags & CCF_USE_LOCAL_ABC) 288 abc_val = ccv->labc; 289 else 290 abc_val = V_tcp_abc_l_var; 291 if ((ccv->flags & CCF_HYSTART_ALLOWED) && 292 (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) && 293 ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) { 294 /* 295 * Hystart is allowed and still enabled and we are not yet 296 * in CSS. Lets check to see if we can make a decision on 297 * if we need to go into CSS. 298 */ 299 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 300 (nreno->css_current_round_minrtt != 0xffffffff) && 301 (nreno->css_lastround_minrtt != 0xffffffff)) { 302 uint32_t rtt_thresh; 303 304 /* Clamp (minrtt_thresh, lastround/8, maxrtt_thresh) */ 305 rtt_thresh = (nreno->css_lastround_minrtt >> 3); 306 if (rtt_thresh < hystart_minrtt_thresh) 307 rtt_thresh = hystart_minrtt_thresh; 308 if (rtt_thresh > hystart_maxrtt_thresh) 309 rtt_thresh = hystart_maxrtt_thresh; 310 newreno_log_hystart_event(ccv, nreno, 1, rtt_thresh); 311 if (nreno->css_current_round_minrtt >= (nreno->css_lastround_minrtt + rtt_thresh)) { 312 /* Enter CSS */ 313 nreno->newreno_flags |= CC_NEWRENO_HYSTART_IN_CSS; 314 nreno->css_fas_at_css_entry = nreno->css_lowrtt_fas; 315 /* 316 * The draft (v4) calls for us to set baseline to css_current_round_min 317 * but that can cause an oscillation. We probably shoudl be using 318 * css_lastround_minrtt, but the authors insist that will cause 319 * issues on exiting early. We will leave the draft version for now 320 * but I suspect this is incorrect. 321 */ 322 nreno->css_baseline_minrtt = nreno->css_current_round_minrtt; 323 nreno->css_entered_at_round = nreno->css_current_round; 324 newreno_log_hystart_event(ccv, nreno, 2, rtt_thresh); 325 } 326 } 327 } 328 if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) 329 incr = min(ccv->bytes_this_ack, 330 ccv->nsegs * abc_val * 331 CCV(ccv, t_maxseg)); 332 else 333 incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); 334 335 /* Only if Hystart is enabled will the flag get set */ 336 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 337 incr /= hystart_css_growth_div; 338 newreno_log_hystart_event(ccv, nreno, 3, incr); 339 } 340 } 341 /* ABC is on by default, so incr equals 0 frequently. */ 342 if (incr > 0) 343 CCV(ccv, snd_cwnd) = min(cw + incr, 344 TCP_MAXWIN << CCV(ccv, snd_scale)); 345 } 346 } 347 348 static void 349 newreno_after_idle(struct cc_var *ccv) 350 { 351 struct newreno *nreno; 352 353 nreno = ccv->cc_data; 354 newreno_cc_after_idle(ccv); 355 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) { 356 /* 357 * Re-enable hystart if we have been idle. 358 */ 359 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 360 nreno->newreno_flags |= CC_NEWRENO_HYSTART_ENABLED; 361 newreno_log_hystart_event(ccv, nreno, 12, CCV(ccv, snd_ssthresh)); 362 } 363 } 364 365 /* 366 * Perform any necessary tasks before we enter congestion recovery. 367 */ 368 static void 369 newreno_cong_signal(struct cc_var *ccv, uint32_t type) 370 { 371 struct newreno *nreno; 372 uint32_t beta, beta_ecn, cwin, factor; 373 u_int mss; 374 375 cwin = CCV(ccv, snd_cwnd); 376 mss = tcp_fixed_maxseg(ccv->ccvc.tcp); 377 nreno = ccv->cc_data; 378 beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;; 379 beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn; 380 /* 381 * Note that we only change the backoff for ECN if the 382 * global sysctl V_cc_do_abe is set <or> the stack itself 383 * has set a flag in our newreno_flags (due to pacing) telling 384 * us to use the lower valued back-off. 385 */ 386 if ((type == CC_ECN) && 387 (V_cc_do_abe || 388 ((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN_ENABLED)))) 389 factor = beta_ecn; 390 else 391 factor = beta; 392 393 /* Catch algos which mistakenly leak private signal types. */ 394 KASSERT((type & CC_SIGPRIVMASK) == 0, 395 ("%s: congestion signal type 0x%08x is private\n", __func__, type)); 396 397 cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss), 398 2) * mss; 399 400 switch (type) { 401 case CC_NDUPACK: 402 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 403 /* Make sure the flags are all off we had a loss */ 404 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 405 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 406 newreno_log_hystart_event(ccv, nreno, 10, CCV(ccv, snd_ssthresh)); 407 } 408 if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { 409 if (IN_CONGRECOVERY(CCV(ccv, t_flags) && 410 V_cc_do_abe && V_cc_abe_frlossreduce)) { 411 CCV(ccv, snd_ssthresh) = 412 ((uint64_t)CCV(ccv, snd_ssthresh) * 413 (uint64_t)beta) / (uint64_t)beta_ecn; 414 } 415 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) 416 CCV(ccv, snd_ssthresh) = cwin; 417 ENTER_RECOVERY(CCV(ccv, t_flags)); 418 } 419 break; 420 case CC_ECN: 421 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 422 /* Make sure the flags are all off we had a loss */ 423 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 424 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 425 newreno_log_hystart_event(ccv, nreno, 9, CCV(ccv, snd_ssthresh)); 426 } 427 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { 428 CCV(ccv, snd_ssthresh) = cwin; 429 CCV(ccv, snd_cwnd) = cwin; 430 ENTER_CONGRECOVERY(CCV(ccv, t_flags)); 431 } 432 break; 433 case CC_RTO: 434 CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd), 435 CCV(ccv, snd_cwnd)) / 2 / mss, 436 2) * mss; 437 CCV(ccv, snd_cwnd) = mss; 438 break; 439 } 440 } 441 442 static int 443 newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf) 444 { 445 struct newreno *nreno; 446 struct cc_newreno_opts *opt; 447 448 if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts)) 449 return (EMSGSIZE); 450 451 if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo) 452 return (ENOPROTOOPT); 453 454 nreno = (struct newreno *)ccv->cc_data; 455 opt = buf; 456 switch (sopt->sopt_dir) { 457 case SOPT_SET: 458 switch (opt->name) { 459 case CC_NEWRENO_BETA: 460 nreno->beta = opt->val; 461 break; 462 case CC_NEWRENO_BETA_ECN: 463 nreno->beta_ecn = opt->val; 464 nreno->newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED; 465 break; 466 default: 467 return (ENOPROTOOPT); 468 } 469 break; 470 case SOPT_GET: 471 switch (opt->name) { 472 case CC_NEWRENO_BETA: 473 opt->val = nreno->beta; 474 break; 475 case CC_NEWRENO_BETA_ECN: 476 opt->val = nreno->beta_ecn; 477 break; 478 default: 479 return (ENOPROTOOPT); 480 } 481 break; 482 default: 483 return (EINVAL); 484 } 485 486 return (0); 487 } 488 489 static int 490 newreno_beta_handler(SYSCTL_HANDLER_ARGS) 491 { 492 int error; 493 uint32_t new; 494 495 new = *(uint32_t *)arg1; 496 error = sysctl_handle_int(oidp, &new, 0, req); 497 if (error == 0 && req->newptr != NULL ) { 498 if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe) 499 error = EACCES; 500 else if (new == 0 || new > 100) 501 error = EINVAL; 502 else 503 *(uint32_t *)arg1 = new; 504 } 505 506 return (error); 507 } 508 509 static void 510 newreno_newround(struct cc_var *ccv, uint32_t round_cnt) 511 { 512 struct newreno *nreno; 513 514 nreno = (struct newreno *)ccv->cc_data; 515 /* We have entered a new round */ 516 nreno->css_lastround_minrtt = nreno->css_current_round_minrtt; 517 nreno->css_current_round_minrtt = 0xffffffff; 518 nreno->css_rttsample_count = 0; 519 nreno->css_current_round = round_cnt; 520 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) && 521 ((round_cnt - nreno->css_entered_at_round) >= hystart_css_rounds)) { 522 /* Enter CA */ 523 if (ccv->flags & CCF_HYSTART_CAN_SH_CWND) { 524 /* 525 * We engage more than snd_ssthresh, engage 526 * the brakes!! Though we will stay in SS to 527 * creep back up again, so lets leave CSS active 528 * and give us hystart_css_rounds more rounds. 529 */ 530 if (ccv->flags & CCF_HYSTART_CONS_SSTH) { 531 CCV(ccv, snd_ssthresh) = ((nreno->css_lowrtt_fas + nreno->css_fas_at_css_entry) / 2); 532 } else { 533 CCV(ccv, snd_ssthresh) = nreno->css_lowrtt_fas; 534 } 535 CCV(ccv, snd_cwnd) = nreno->css_fas_at_css_entry; 536 nreno->css_entered_at_round = round_cnt; 537 } else { 538 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); 539 /* Turn off the CSS flag */ 540 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 541 /* Disable use of CSS in the future except long idle */ 542 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 543 } 544 newreno_log_hystart_event(ccv, nreno, 6, CCV(ccv, snd_ssthresh)); 545 } 546 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 547 newreno_log_hystart_event(ccv, nreno, 4, round_cnt); 548 } 549 550 static void 551 newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas) 552 { 553 struct newreno *nreno; 554 555 nreno = (struct newreno *)ccv->cc_data; 556 if (rxtcnt > 1) { 557 /* 558 * Only look at RTT's that are non-ambiguous. 559 */ 560 return; 561 } 562 nreno->css_rttsample_count++; 563 nreno->css_last_fas = fas; 564 if (nreno->css_current_round_minrtt > usec_rtt) { 565 nreno->css_current_round_minrtt = usec_rtt; 566 nreno->css_lowrtt_fas = nreno->css_last_fas; 567 } 568 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 569 (nreno->css_current_round_minrtt != 0xffffffff) && 570 (nreno->css_current_round_minrtt < nreno->css_baseline_minrtt) && 571 (nreno->css_lastround_minrtt != 0xffffffff)) { 572 /* 573 * We were in CSS and the RTT is now less, we 574 * entered CSS erroneously. 575 */ 576 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 577 newreno_log_hystart_event(ccv, nreno, 8, nreno->css_baseline_minrtt); 578 nreno->css_baseline_minrtt = 0xffffffff; 579 } 580 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 581 newreno_log_hystart_event(ccv, nreno, 5, usec_rtt); 582 } 583 584 SYSCTL_DECL(_net_inet_tcp_cc_newreno); 585 SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno, 586 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 587 "New Reno related settings"); 588 589 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta, 590 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 591 &VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU", 592 "New Reno beta, specified as number between 1 and 100"); 593 594 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn, 595 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 596 &VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU", 597 "New Reno beta ecn, specified as number between 1 and 100"); 598 599 DECLARE_CC_MODULE(newreno, &newreno_cc_algo); 600 MODULE_VERSION(newreno, 2);
Cache object: a622ecb30f3d5cebdb57af175194027e
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