1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause 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 #include <sys/param.h> 60 #include <sys/kernel.h> 61 #include <sys/malloc.h> 62 #include <sys/module.h> 63 #include <sys/socket.h> 64 #include <sys/lock.h> 65 #include <sys/mutex.h> 66 #include <sys/socketvar.h> 67 #include <sys/sysctl.h> 68 #include <sys/systm.h> 69 70 #include <net/vnet.h> 71 72 #include <net/route.h> 73 #include <net/route/nhop.h> 74 75 #include <netinet/in_pcb.h> 76 #include <netinet/in.h> 77 #include <netinet/in_pcb.h> 78 #include <netinet/tcp.h> 79 #include <netinet/tcp_seq.h> 80 #include <netinet/tcp_var.h> 81 #include <netinet/tcp_log_buf.h> 82 #include <netinet/tcp_hpts.h> 83 #include <netinet/cc/cc.h> 84 #include <netinet/cc/cc_module.h> 85 #include <netinet/cc/cc_newreno.h> 86 87 static void newreno_cb_destroy(struct cc_var *ccv); 88 static void newreno_ack_received(struct cc_var *ccv, uint16_t type); 89 static void newreno_after_idle(struct cc_var *ccv); 90 static void newreno_cong_signal(struct cc_var *ccv, uint32_t type); 91 static int newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf); 92 static void newreno_newround(struct cc_var *ccv, uint32_t round_cnt); 93 static void newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas); 94 static int newreno_cb_init(struct cc_var *ccv, void *); 95 static size_t newreno_data_sz(void); 96 97 98 VNET_DECLARE(uint32_t, newreno_beta); 99 #define V_newreno_beta VNET(newreno_beta) 100 VNET_DECLARE(uint32_t, newreno_beta_ecn); 101 #define V_newreno_beta_ecn VNET(newreno_beta_ecn) 102 103 struct cc_algo newreno_cc_algo = { 104 .name = "newreno", 105 .cb_destroy = newreno_cb_destroy, 106 .ack_received = newreno_ack_received, 107 .after_idle = newreno_after_idle, 108 .cong_signal = newreno_cong_signal, 109 .post_recovery = newreno_cc_post_recovery, 110 .ctl_output = newreno_ctl_output, 111 .newround = newreno_newround, 112 .rttsample = newreno_rttsample, 113 .cb_init = newreno_cb_init, 114 .cc_data_sz = newreno_data_sz, 115 }; 116 117 static void 118 newreno_log_hystart_event(struct cc_var *ccv, struct newreno *nreno, uint8_t mod, uint32_t flex1) 119 { 120 /* 121 * Types of logs (mod value) 122 * 1 - rtt_thresh in flex1, checking to see if RTT is to great. 123 * 2 - rtt is too great, rtt_thresh in flex1. 124 * 3 - CSS is active incr in flex1 125 * 4 - A new round is beginning flex1 is round count 126 * 5 - A new RTT measurement flex1 is the new measurement. 127 * 6 - We enter CA ssthresh is also in flex1. 128 * 7 - Socket option to change hystart executed opt.val in flex1. 129 * 8 - Back out of CSS into SS, flex1 is the css_baseline_minrtt 130 * 9 - We enter CA, via an ECN mark. 131 * 10 - We enter CA, via a loss. 132 * 11 - We have slipped out of SS into CA via cwnd growth. 133 * 12 - After idle has re-enabled hystart++ 134 */ 135 struct tcpcb *tp; 136 137 if (hystart_bblogs == 0) 138 return; 139 tp = ccv->ccvc.tcp; 140 if (tcp_bblogging_on(tp)) { 141 union tcp_log_stackspecific log; 142 struct timeval tv; 143 144 memset(&log, 0, sizeof(log)); 145 log.u_bbr.flex1 = flex1; 146 log.u_bbr.flex2 = nreno->css_current_round_minrtt; 147 log.u_bbr.flex3 = nreno->css_lastround_minrtt; 148 log.u_bbr.flex4 = nreno->css_rttsample_count; 149 log.u_bbr.flex5 = nreno->css_entered_at_round; 150 log.u_bbr.flex6 = nreno->css_baseline_minrtt; 151 /* We only need bottom 16 bits of flags */ 152 log.u_bbr.flex7 = nreno->newreno_flags & 0x0000ffff; 153 log.u_bbr.flex8 = mod; 154 log.u_bbr.epoch = nreno->css_current_round; 155 log.u_bbr.timeStamp = tcp_get_usecs(&tv); 156 log.u_bbr.lt_epoch = nreno->css_fas_at_css_entry; 157 log.u_bbr.pkts_out = nreno->css_last_fas; 158 log.u_bbr.delivered = nreno->css_lowrtt_fas; 159 log.u_bbr.pkt_epoch = ccv->flags; 160 TCP_LOG_EVENTP(tp, NULL, 161 &tptosocket(tp)->so_rcv, 162 &tptosocket(tp)->so_snd, 163 TCP_HYSTART, 0, 164 0, &log, false, &tv); 165 } 166 } 167 168 static size_t 169 newreno_data_sz(void) 170 { 171 return (sizeof(struct newreno)); 172 } 173 174 static int 175 newreno_cb_init(struct cc_var *ccv, void *ptr) 176 { 177 struct newreno *nreno; 178 179 INP_WLOCK_ASSERT(tptoinpcb(ccv->ccvc.tcp)); 180 if (ptr == NULL) { 181 ccv->cc_data = malloc(sizeof(struct newreno), M_CC_MEM, M_NOWAIT); 182 if (ccv->cc_data == NULL) 183 return (ENOMEM); 184 } else 185 ccv->cc_data = ptr; 186 nreno = (struct newreno *)ccv->cc_data; 187 /* NB: nreno is not zeroed, so initialise all fields. */ 188 nreno->beta = V_newreno_beta; 189 nreno->beta_ecn = V_newreno_beta_ecn; 190 /* 191 * We set the enabled flag so that if 192 * the socket option gets strobed and 193 * we have not hit a loss 194 */ 195 nreno->newreno_flags = CC_NEWRENO_HYSTART_ENABLED; 196 /* At init set both to infinity */ 197 nreno->css_lastround_minrtt = 0xffffffff; 198 nreno->css_current_round_minrtt = 0xffffffff; 199 nreno->css_current_round = 0; 200 nreno->css_baseline_minrtt = 0xffffffff; 201 nreno->css_rttsample_count = 0; 202 nreno->css_entered_at_round = 0; 203 nreno->css_fas_at_css_entry = 0; 204 nreno->css_lowrtt_fas = 0; 205 nreno->css_last_fas = 0; 206 return (0); 207 } 208 209 static void 210 newreno_cb_destroy(struct cc_var *ccv) 211 { 212 free(ccv->cc_data, M_CC_MEM); 213 } 214 215 static void 216 newreno_ack_received(struct cc_var *ccv, uint16_t type) 217 { 218 struct newreno *nreno; 219 220 nreno = ccv->cc_data; 221 if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && 222 (ccv->flags & CCF_CWND_LIMITED)) { 223 u_int cw = CCV(ccv, snd_cwnd); 224 u_int incr = CCV(ccv, t_maxseg); 225 226 /* 227 * Regular in-order ACK, open the congestion window. 228 * Method depends on which congestion control state we're 229 * in (slow start or cong avoid) and if ABC (RFC 3465) is 230 * enabled. 231 * 232 * slow start: cwnd <= ssthresh 233 * cong avoid: cwnd > ssthresh 234 * 235 * slow start and ABC (RFC 3465): 236 * Grow cwnd exponentially by the amount of data 237 * ACKed capping the max increment per ACK to 238 * (abc_l_var * maxseg) bytes. 239 * 240 * slow start without ABC (RFC 5681): 241 * Grow cwnd exponentially by maxseg per ACK. 242 * 243 * cong avoid and ABC (RFC 3465): 244 * Grow cwnd linearly by maxseg per RTT for each 245 * cwnd worth of ACKed data. 246 * 247 * cong avoid without ABC (RFC 5681): 248 * Grow cwnd linearly by approximately maxseg per RTT using 249 * maxseg^2 / cwnd per ACK as the increment. 250 * If cwnd > maxseg^2, fix the cwnd increment at 1 byte to 251 * avoid capping cwnd. 252 */ 253 if (cw > CCV(ccv, snd_ssthresh)) { 254 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 255 /* 256 * We have slipped into CA with 257 * CSS active. Deactivate all. 258 */ 259 /* Turn off the CSS flag */ 260 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 261 /* Disable use of CSS in the future except long idle */ 262 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 263 newreno_log_hystart_event(ccv, nreno, 11, CCV(ccv, snd_ssthresh)); 264 } 265 if (V_tcp_do_rfc3465) { 266 if (ccv->flags & CCF_ABC_SENTAWND) 267 ccv->flags &= ~CCF_ABC_SENTAWND; 268 else 269 incr = 0; 270 } else 271 incr = max((incr * incr / cw), 1); 272 } else if (V_tcp_do_rfc3465) { 273 /* 274 * In slow-start with ABC enabled and no RTO in sight? 275 * (Must not use abc_l_var > 1 if slow starting after 276 * an RTO. On RTO, snd_nxt = snd_una, so the 277 * snd_nxt == snd_max check is sufficient to 278 * handle this). 279 * 280 * XXXLAS: Find a way to signal SS after RTO that 281 * doesn't rely on tcpcb vars. 282 */ 283 uint16_t abc_val; 284 285 if (ccv->flags & CCF_USE_LOCAL_ABC) 286 abc_val = ccv->labc; 287 else 288 abc_val = V_tcp_abc_l_var; 289 if ((ccv->flags & CCF_HYSTART_ALLOWED) && 290 (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) && 291 ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) { 292 /* 293 * Hystart is allowed and still enabled and we are not yet 294 * in CSS. Lets check to see if we can make a decision on 295 * if we need to go into CSS. 296 */ 297 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 298 (nreno->css_current_round_minrtt != 0xffffffff) && 299 (nreno->css_lastround_minrtt != 0xffffffff)) { 300 uint32_t rtt_thresh; 301 302 /* Clamp (minrtt_thresh, lastround/8, maxrtt_thresh) */ 303 rtt_thresh = (nreno->css_lastround_minrtt >> 3); 304 if (rtt_thresh < hystart_minrtt_thresh) 305 rtt_thresh = hystart_minrtt_thresh; 306 if (rtt_thresh > hystart_maxrtt_thresh) 307 rtt_thresh = hystart_maxrtt_thresh; 308 newreno_log_hystart_event(ccv, nreno, 1, rtt_thresh); 309 if (nreno->css_current_round_minrtt >= (nreno->css_lastround_minrtt + rtt_thresh)) { 310 /* Enter CSS */ 311 nreno->newreno_flags |= CC_NEWRENO_HYSTART_IN_CSS; 312 nreno->css_fas_at_css_entry = nreno->css_lowrtt_fas; 313 /* 314 * The draft (v4) calls for us to set baseline to css_current_round_min 315 * but that can cause an oscillation. We probably shoudl be using 316 * css_lastround_minrtt, but the authors insist that will cause 317 * issues on exiting early. We will leave the draft version for now 318 * but I suspect this is incorrect. 319 */ 320 nreno->css_baseline_minrtt = nreno->css_current_round_minrtt; 321 nreno->css_entered_at_round = nreno->css_current_round; 322 newreno_log_hystart_event(ccv, nreno, 2, rtt_thresh); 323 } 324 } 325 } 326 if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) 327 incr = min(ccv->bytes_this_ack, 328 ccv->nsegs * abc_val * 329 CCV(ccv, t_maxseg)); 330 else 331 incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); 332 333 /* Only if Hystart is enabled will the flag get set */ 334 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 335 incr /= hystart_css_growth_div; 336 newreno_log_hystart_event(ccv, nreno, 3, incr); 337 } 338 } 339 /* ABC is on by default, so incr equals 0 frequently. */ 340 if (incr > 0) 341 CCV(ccv, snd_cwnd) = min(cw + incr, 342 TCP_MAXWIN << CCV(ccv, snd_scale)); 343 } 344 } 345 346 static void 347 newreno_after_idle(struct cc_var *ccv) 348 { 349 struct newreno *nreno; 350 351 nreno = ccv->cc_data; 352 newreno_cc_after_idle(ccv); 353 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) { 354 /* 355 * Re-enable hystart if we have been idle. 356 */ 357 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 358 nreno->newreno_flags |= CC_NEWRENO_HYSTART_ENABLED; 359 newreno_log_hystart_event(ccv, nreno, 12, CCV(ccv, snd_ssthresh)); 360 } 361 } 362 363 /* 364 * Perform any necessary tasks before we enter congestion recovery. 365 */ 366 static void 367 newreno_cong_signal(struct cc_var *ccv, uint32_t type) 368 { 369 struct newreno *nreno; 370 uint32_t beta, beta_ecn, cwin, factor; 371 u_int mss; 372 373 cwin = CCV(ccv, snd_cwnd); 374 mss = tcp_fixed_maxseg(ccv->ccvc.tcp); 375 nreno = ccv->cc_data; 376 beta = (nreno == NULL) ? V_newreno_beta : nreno->beta;; 377 beta_ecn = (nreno == NULL) ? V_newreno_beta_ecn : nreno->beta_ecn; 378 /* 379 * Note that we only change the backoff for ECN if the 380 * global sysctl V_cc_do_abe is set <or> the stack itself 381 * has set a flag in our newreno_flags (due to pacing) telling 382 * us to use the lower valued back-off. 383 */ 384 if ((type == CC_ECN) && 385 (V_cc_do_abe || 386 ((nreno != NULL) && (nreno->newreno_flags & CC_NEWRENO_BETA_ECN_ENABLED)))) 387 factor = beta_ecn; 388 else 389 factor = beta; 390 391 /* Catch algos which mistakenly leak private signal types. */ 392 KASSERT((type & CC_SIGPRIVMASK) == 0, 393 ("%s: congestion signal type 0x%08x is private\n", __func__, type)); 394 395 cwin = max(((uint64_t)cwin * (uint64_t)factor) / (100ULL * (uint64_t)mss), 396 2) * mss; 397 398 switch (type) { 399 case CC_NDUPACK: 400 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 401 /* Make sure the flags are all off we had a loss */ 402 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 403 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 404 newreno_log_hystart_event(ccv, nreno, 10, CCV(ccv, snd_ssthresh)); 405 } 406 if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { 407 if (IN_CONGRECOVERY(CCV(ccv, t_flags) && 408 V_cc_do_abe && V_cc_abe_frlossreduce)) { 409 CCV(ccv, snd_ssthresh) = 410 ((uint64_t)CCV(ccv, snd_ssthresh) * 411 (uint64_t)beta) / (uint64_t)beta_ecn; 412 } 413 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) 414 CCV(ccv, snd_ssthresh) = cwin; 415 ENTER_RECOVERY(CCV(ccv, t_flags)); 416 } 417 break; 418 case CC_ECN: 419 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 420 /* Make sure the flags are all off we had a loss */ 421 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 422 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 423 newreno_log_hystart_event(ccv, nreno, 9, CCV(ccv, snd_ssthresh)); 424 } 425 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { 426 CCV(ccv, snd_ssthresh) = cwin; 427 CCV(ccv, snd_cwnd) = cwin; 428 ENTER_CONGRECOVERY(CCV(ccv, t_flags)); 429 } 430 break; 431 case CC_RTO: 432 CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd), 433 CCV(ccv, snd_cwnd)) / 2 / mss, 434 2) * mss; 435 CCV(ccv, snd_cwnd) = mss; 436 break; 437 } 438 } 439 440 static int 441 newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf) 442 { 443 struct newreno *nreno; 444 struct cc_newreno_opts *opt; 445 446 if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts)) 447 return (EMSGSIZE); 448 449 if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo) 450 return (ENOPROTOOPT); 451 452 nreno = (struct newreno *)ccv->cc_data; 453 opt = buf; 454 switch (sopt->sopt_dir) { 455 case SOPT_SET: 456 switch (opt->name) { 457 case CC_NEWRENO_BETA: 458 nreno->beta = opt->val; 459 break; 460 case CC_NEWRENO_BETA_ECN: 461 nreno->beta_ecn = opt->val; 462 nreno->newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED; 463 break; 464 default: 465 return (ENOPROTOOPT); 466 } 467 break; 468 case SOPT_GET: 469 switch (opt->name) { 470 case CC_NEWRENO_BETA: 471 opt->val = nreno->beta; 472 break; 473 case CC_NEWRENO_BETA_ECN: 474 opt->val = nreno->beta_ecn; 475 break; 476 default: 477 return (ENOPROTOOPT); 478 } 479 break; 480 default: 481 return (EINVAL); 482 } 483 484 return (0); 485 } 486 487 static int 488 newreno_beta_handler(SYSCTL_HANDLER_ARGS) 489 { 490 int error; 491 uint32_t new; 492 493 new = *(uint32_t *)arg1; 494 error = sysctl_handle_int(oidp, &new, 0, req); 495 if (error == 0 && req->newptr != NULL ) { 496 if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe) 497 error = EACCES; 498 else if (new == 0 || new > 100) 499 error = EINVAL; 500 else 501 *(uint32_t *)arg1 = new; 502 } 503 504 return (error); 505 } 506 507 static void 508 newreno_newround(struct cc_var *ccv, uint32_t round_cnt) 509 { 510 struct newreno *nreno; 511 512 nreno = (struct newreno *)ccv->cc_data; 513 /* We have entered a new round */ 514 nreno->css_lastround_minrtt = nreno->css_current_round_minrtt; 515 nreno->css_current_round_minrtt = 0xffffffff; 516 nreno->css_rttsample_count = 0; 517 nreno->css_current_round = round_cnt; 518 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) && 519 ((round_cnt - nreno->css_entered_at_round) >= hystart_css_rounds)) { 520 /* Enter CA */ 521 if (ccv->flags & CCF_HYSTART_CAN_SH_CWND) { 522 /* 523 * We engage more than snd_ssthresh, engage 524 * the brakes!! Though we will stay in SS to 525 * creep back up again, so lets leave CSS active 526 * and give us hystart_css_rounds more rounds. 527 */ 528 if (ccv->flags & CCF_HYSTART_CONS_SSTH) { 529 CCV(ccv, snd_ssthresh) = ((nreno->css_lowrtt_fas + nreno->css_fas_at_css_entry) / 2); 530 } else { 531 CCV(ccv, snd_ssthresh) = nreno->css_lowrtt_fas; 532 } 533 CCV(ccv, snd_cwnd) = nreno->css_fas_at_css_entry; 534 nreno->css_entered_at_round = round_cnt; 535 } else { 536 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); 537 /* Turn off the CSS flag */ 538 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 539 /* Disable use of CSS in the future except long idle */ 540 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 541 } 542 newreno_log_hystart_event(ccv, nreno, 6, CCV(ccv, snd_ssthresh)); 543 } 544 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 545 newreno_log_hystart_event(ccv, nreno, 4, round_cnt); 546 } 547 548 static void 549 newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas) 550 { 551 struct newreno *nreno; 552 553 nreno = (struct newreno *)ccv->cc_data; 554 if (rxtcnt > 1) { 555 /* 556 * Only look at RTT's that are non-ambiguous. 557 */ 558 return; 559 } 560 nreno->css_rttsample_count++; 561 nreno->css_last_fas = fas; 562 if (nreno->css_current_round_minrtt > usec_rtt) { 563 nreno->css_current_round_minrtt = usec_rtt; 564 nreno->css_lowrtt_fas = nreno->css_last_fas; 565 } 566 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 567 (nreno->css_current_round_minrtt != 0xffffffff) && 568 (nreno->css_current_round_minrtt < nreno->css_baseline_minrtt) && 569 (nreno->css_lastround_minrtt != 0xffffffff)) { 570 /* 571 * We were in CSS and the RTT is now less, we 572 * entered CSS erroneously. 573 */ 574 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 575 newreno_log_hystart_event(ccv, nreno, 8, nreno->css_baseline_minrtt); 576 nreno->css_baseline_minrtt = 0xffffffff; 577 } 578 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 579 newreno_log_hystart_event(ccv, nreno, 5, usec_rtt); 580 } 581 582 SYSCTL_DECL(_net_inet_tcp_cc_newreno); 583 SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno, 584 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 585 "New Reno related settings"); 586 587 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta, 588 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 589 &VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU", 590 "New Reno beta, specified as number between 1 and 100"); 591 592 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn, 593 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 594 &VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU", 595 "New Reno beta ecn, specified as number between 1 and 100"); 596 597 DECLARE_CC_MODULE(newreno, &newreno_cc_algo); 598 MODULE_VERSION(newreno, 2); 599