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/param.h> 59 #include <sys/kernel.h> 60 #include <sys/malloc.h> 61 #include <sys/module.h> 62 #include <sys/socket.h> 63 #include <sys/lock.h> 64 #include <sys/mutex.h> 65 #include <sys/socketvar.h> 66 #include <sys/sysctl.h> 67 #include <sys/systm.h> 68 69 #include <net/vnet.h> 70 71 #include <net/route.h> 72 #include <net/route/nhop.h> 73 74 #include <netinet/in_pcb.h> 75 #include <netinet/in.h> 76 #include <netinet/in_pcb.h> 77 #include <netinet/tcp.h> 78 #include <netinet/tcp_seq.h> 79 #include <netinet/tcp_var.h> 80 #include <netinet/tcp_log_buf.h> 81 #include <netinet/tcp_hpts.h> 82 #include <netinet/cc/cc.h> 83 #include <netinet/cc/cc_module.h> 84 #include <netinet/cc/cc_newreno.h> 85 86 static void newreno_cb_destroy(struct cc_var *ccv); 87 static void newreno_ack_received(struct cc_var *ccv, uint16_t type); 88 static void newreno_after_idle(struct cc_var *ccv); 89 static void newreno_cong_signal(struct cc_var *ccv, uint32_t type); 90 static int newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf); 91 static void newreno_newround(struct cc_var *ccv, uint32_t round_cnt); 92 static void newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas); 93 static int newreno_cb_init(struct cc_var *ccv, void *); 94 static size_t newreno_data_sz(void); 95 96 97 VNET_DECLARE(uint32_t, newreno_beta); 98 #define V_newreno_beta VNET(newreno_beta) 99 VNET_DECLARE(uint32_t, newreno_beta_ecn); 100 #define V_newreno_beta_ecn VNET(newreno_beta_ecn) 101 102 struct cc_algo newreno_cc_algo = { 103 .name = "newreno", 104 .cb_destroy = newreno_cb_destroy, 105 .ack_received = newreno_ack_received, 106 .after_idle = newreno_after_idle, 107 .cong_signal = newreno_cong_signal, 108 .post_recovery = newreno_cc_post_recovery, 109 .ctl_output = newreno_ctl_output, 110 .newround = newreno_newround, 111 .rttsample = newreno_rttsample, 112 .cb_init = newreno_cb_init, 113 .cc_data_sz = newreno_data_sz, 114 }; 115 116 static void 117 newreno_log_hystart_event(struct cc_var *ccv, struct newreno *nreno, uint8_t mod, uint32_t flex1) 118 { 119 /* 120 * Types of logs (mod value) 121 * 1 - rtt_thresh in flex1, checking to see if RTT is to great. 122 * 2 - rtt is too great, rtt_thresh in flex1. 123 * 3 - CSS is active incr in flex1 124 * 4 - A new round is beginning flex1 is round count 125 * 5 - A new RTT measurement flex1 is the new measurement. 126 * 6 - We enter CA ssthresh is also in flex1. 127 * 7 - Socket option to change hystart executed opt.val in flex1. 128 * 8 - Back out of CSS into SS, flex1 is the css_baseline_minrtt 129 * 9 - We enter CA, via an ECN mark. 130 * 10 - We enter CA, via a loss. 131 * 11 - We have slipped out of SS into CA via cwnd growth. 132 * 12 - After idle has re-enabled hystart++ 133 */ 134 struct tcpcb *tp; 135 136 if (hystart_bblogs == 0) 137 return; 138 tp = ccv->ccvc.tcp; 139 if (tcp_bblogging_on(tp)) { 140 union tcp_log_stackspecific log; 141 struct timeval tv; 142 143 memset(&log, 0, sizeof(log)); 144 log.u_bbr.flex1 = flex1; 145 log.u_bbr.flex2 = nreno->css_current_round_minrtt; 146 log.u_bbr.flex3 = nreno->css_lastround_minrtt; 147 log.u_bbr.flex4 = nreno->css_rttsample_count; 148 log.u_bbr.flex5 = nreno->css_entered_at_round; 149 log.u_bbr.flex6 = nreno->css_baseline_minrtt; 150 /* We only need bottom 16 bits of flags */ 151 log.u_bbr.flex7 = nreno->newreno_flags & 0x0000ffff; 152 log.u_bbr.flex8 = mod; 153 log.u_bbr.epoch = nreno->css_current_round; 154 log.u_bbr.timeStamp = tcp_get_usecs(&tv); 155 log.u_bbr.lt_epoch = nreno->css_fas_at_css_entry; 156 log.u_bbr.pkts_out = nreno->css_last_fas; 157 log.u_bbr.delivered = nreno->css_lowrtt_fas; 158 log.u_bbr.pkt_epoch = ccv->flags; 159 TCP_LOG_EVENTP(tp, NULL, 160 &tptosocket(tp)->so_rcv, 161 &tptosocket(tp)->so_snd, 162 TCP_HYSTART, 0, 163 0, &log, false, &tv); 164 } 165 } 166 167 static size_t 168 newreno_data_sz(void) 169 { 170 return (sizeof(struct newreno)); 171 } 172 173 static int 174 newreno_cb_init(struct cc_var *ccv, void *ptr) 175 { 176 struct newreno *nreno; 177 178 INP_WLOCK_ASSERT(tptoinpcb(ccv->ccvc.tcp)); 179 if (ptr == NULL) { 180 ccv->cc_data = malloc(sizeof(struct newreno), M_CC_MEM, M_NOWAIT); 181 if (ccv->cc_data == NULL) 182 return (ENOMEM); 183 } else 184 ccv->cc_data = ptr; 185 nreno = (struct newreno *)ccv->cc_data; 186 /* NB: nreno is not zeroed, so initialise all fields. */ 187 nreno->beta = V_newreno_beta; 188 nreno->beta_ecn = V_newreno_beta_ecn; 189 /* 190 * We set the enabled flag so that if 191 * the socket option gets strobed and 192 * we have not hit a loss 193 */ 194 nreno->newreno_flags = CC_NEWRENO_HYSTART_ENABLED; 195 /* At init set both to infinity */ 196 nreno->css_lastround_minrtt = 0xffffffff; 197 nreno->css_current_round_minrtt = 0xffffffff; 198 nreno->css_current_round = 0; 199 nreno->css_baseline_minrtt = 0xffffffff; 200 nreno->css_rttsample_count = 0; 201 nreno->css_entered_at_round = 0; 202 nreno->css_fas_at_css_entry = 0; 203 nreno->css_lowrtt_fas = 0; 204 nreno->css_last_fas = 0; 205 return (0); 206 } 207 208 static void 209 newreno_cb_destroy(struct cc_var *ccv) 210 { 211 free(ccv->cc_data, M_CC_MEM); 212 } 213 214 static void 215 newreno_ack_received(struct cc_var *ccv, uint16_t type) 216 { 217 struct newreno *nreno; 218 219 nreno = ccv->cc_data; 220 if (type == CC_ACK && !IN_RECOVERY(CCV(ccv, t_flags)) && 221 (ccv->flags & CCF_CWND_LIMITED)) { 222 u_int cw = CCV(ccv, snd_cwnd); 223 u_int incr = CCV(ccv, t_maxseg); 224 225 /* 226 * Regular in-order ACK, open the congestion window. 227 * Method depends on which congestion control state we're 228 * in (slow start or cong avoid) and if ABC (RFC 3465) is 229 * enabled. 230 * 231 * slow start: cwnd <= ssthresh 232 * cong avoid: cwnd > ssthresh 233 * 234 * slow start and ABC (RFC 3465): 235 * Grow cwnd exponentially by the amount of data 236 * ACKed capping the max increment per ACK to 237 * (abc_l_var * maxseg) bytes. 238 * 239 * slow start without ABC (RFC 5681): 240 * Grow cwnd exponentially by maxseg per ACK. 241 * 242 * cong avoid and ABC (RFC 3465): 243 * Grow cwnd linearly by maxseg per RTT for each 244 * cwnd worth of ACKed data. 245 * 246 * cong avoid without ABC (RFC 5681): 247 * Grow cwnd linearly by approximately maxseg per RTT using 248 * maxseg^2 / cwnd per ACK as the increment. 249 * If cwnd > maxseg^2, fix the cwnd increment at 1 byte to 250 * avoid capping cwnd. 251 */ 252 if (cw > CCV(ccv, snd_ssthresh)) { 253 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 254 /* 255 * We have slipped into CA with 256 * CSS active. Deactivate all. 257 */ 258 /* Turn off the CSS flag */ 259 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 260 /* Disable use of CSS in the future except long idle */ 261 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 262 newreno_log_hystart_event(ccv, nreno, 11, CCV(ccv, snd_ssthresh)); 263 } 264 if (V_tcp_do_rfc3465) { 265 if (ccv->flags & CCF_ABC_SENTAWND) 266 ccv->flags &= ~CCF_ABC_SENTAWND; 267 else 268 incr = 0; 269 } else 270 incr = max((incr * incr / cw), 1); 271 } else if (V_tcp_do_rfc3465) { 272 /* 273 * In slow-start with ABC enabled and no RTO in sight? 274 * (Must not use abc_l_var > 1 if slow starting after 275 * an RTO. On RTO, snd_nxt = snd_una, so the 276 * snd_nxt == snd_max check is sufficient to 277 * handle this). 278 * 279 * XXXLAS: Find a way to signal SS after RTO that 280 * doesn't rely on tcpcb vars. 281 */ 282 uint16_t abc_val; 283 284 if (ccv->flags & CCF_USE_LOCAL_ABC) 285 abc_val = ccv->labc; 286 else 287 abc_val = V_tcp_abc_l_var; 288 if ((ccv->flags & CCF_HYSTART_ALLOWED) && 289 (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) && 290 ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) == 0)) { 291 /* 292 * Hystart is allowed and still enabled and we are not yet 293 * in CSS. Lets check to see if we can make a decision on 294 * if we need to go into CSS. 295 */ 296 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 297 (nreno->css_current_round_minrtt != 0xffffffff) && 298 (nreno->css_lastround_minrtt != 0xffffffff)) { 299 uint32_t rtt_thresh; 300 301 /* Clamp (minrtt_thresh, lastround/8, maxrtt_thresh) */ 302 rtt_thresh = (nreno->css_lastround_minrtt >> 3); 303 if (rtt_thresh < hystart_minrtt_thresh) 304 rtt_thresh = hystart_minrtt_thresh; 305 if (rtt_thresh > hystart_maxrtt_thresh) 306 rtt_thresh = hystart_maxrtt_thresh; 307 newreno_log_hystart_event(ccv, nreno, 1, rtt_thresh); 308 if (nreno->css_current_round_minrtt >= (nreno->css_lastround_minrtt + rtt_thresh)) { 309 /* Enter CSS */ 310 nreno->newreno_flags |= CC_NEWRENO_HYSTART_IN_CSS; 311 nreno->css_fas_at_css_entry = nreno->css_lowrtt_fas; 312 /* 313 * The draft (v4) calls for us to set baseline to css_current_round_min 314 * but that can cause an oscillation. We probably shoudl be using 315 * css_lastround_minrtt, but the authors insist that will cause 316 * issues on exiting early. We will leave the draft version for now 317 * but I suspect this is incorrect. 318 */ 319 nreno->css_baseline_minrtt = nreno->css_current_round_minrtt; 320 nreno->css_entered_at_round = nreno->css_current_round; 321 newreno_log_hystart_event(ccv, nreno, 2, rtt_thresh); 322 } 323 } 324 } 325 if (CCV(ccv, snd_nxt) == CCV(ccv, snd_max)) 326 incr = min(ccv->bytes_this_ack, 327 ccv->nsegs * abc_val * 328 CCV(ccv, t_maxseg)); 329 else 330 incr = min(ccv->bytes_this_ack, CCV(ccv, t_maxseg)); 331 332 /* Only if Hystart is enabled will the flag get set */ 333 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) { 334 incr /= hystart_css_growth_div; 335 newreno_log_hystart_event(ccv, nreno, 3, incr); 336 } 337 } 338 /* ABC is on by default, so incr equals 0 frequently. */ 339 if (incr > 0) 340 CCV(ccv, snd_cwnd) = min(cw + incr, 341 TCP_MAXWIN << CCV(ccv, snd_scale)); 342 } 343 } 344 345 static void 346 newreno_after_idle(struct cc_var *ccv) 347 { 348 struct newreno *nreno; 349 350 nreno = ccv->cc_data; 351 newreno_cc_after_idle(ccv); 352 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) == 0) { 353 /* 354 * Re-enable hystart if we have been idle. 355 */ 356 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 357 nreno->newreno_flags |= CC_NEWRENO_HYSTART_ENABLED; 358 newreno_log_hystart_event(ccv, nreno, 12, CCV(ccv, snd_ssthresh)); 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 newreno_log_hystart_event(ccv, nreno, 10, CCV(ccv, snd_ssthresh)); 404 } 405 if (!IN_FASTRECOVERY(CCV(ccv, t_flags))) { 406 if (IN_CONGRECOVERY(CCV(ccv, t_flags) && 407 V_cc_do_abe && V_cc_abe_frlossreduce)) { 408 CCV(ccv, snd_ssthresh) = 409 ((uint64_t)CCV(ccv, snd_ssthresh) * 410 (uint64_t)beta) / (uint64_t)beta_ecn; 411 } 412 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) 413 CCV(ccv, snd_ssthresh) = cwin; 414 ENTER_RECOVERY(CCV(ccv, t_flags)); 415 } 416 break; 417 case CC_ECN: 418 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) { 419 /* Make sure the flags are all off we had a loss */ 420 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 421 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 422 newreno_log_hystart_event(ccv, nreno, 9, CCV(ccv, snd_ssthresh)); 423 } 424 if (!IN_CONGRECOVERY(CCV(ccv, t_flags))) { 425 CCV(ccv, snd_ssthresh) = cwin; 426 CCV(ccv, snd_cwnd) = cwin; 427 ENTER_CONGRECOVERY(CCV(ccv, t_flags)); 428 } 429 break; 430 case CC_RTO: 431 CCV(ccv, snd_ssthresh) = max(min(CCV(ccv, snd_wnd), 432 CCV(ccv, snd_cwnd)) / 2 / mss, 433 2) * mss; 434 CCV(ccv, snd_cwnd) = mss; 435 break; 436 } 437 } 438 439 static int 440 newreno_ctl_output(struct cc_var *ccv, struct sockopt *sopt, void *buf) 441 { 442 struct newreno *nreno; 443 struct cc_newreno_opts *opt; 444 445 if (sopt->sopt_valsize != sizeof(struct cc_newreno_opts)) 446 return (EMSGSIZE); 447 448 if (CC_ALGO(ccv->ccvc.tcp) != &newreno_cc_algo) 449 return (ENOPROTOOPT); 450 451 nreno = (struct newreno *)ccv->cc_data; 452 opt = buf; 453 switch (sopt->sopt_dir) { 454 case SOPT_SET: 455 switch (opt->name) { 456 case CC_NEWRENO_BETA: 457 nreno->beta = opt->val; 458 break; 459 case CC_NEWRENO_BETA_ECN: 460 nreno->beta_ecn = opt->val; 461 nreno->newreno_flags |= CC_NEWRENO_BETA_ECN_ENABLED; 462 break; 463 default: 464 return (ENOPROTOOPT); 465 } 466 break; 467 case SOPT_GET: 468 switch (opt->name) { 469 case CC_NEWRENO_BETA: 470 opt->val = nreno->beta; 471 break; 472 case CC_NEWRENO_BETA_ECN: 473 opt->val = nreno->beta_ecn; 474 break; 475 default: 476 return (ENOPROTOOPT); 477 } 478 break; 479 default: 480 return (EINVAL); 481 } 482 483 return (0); 484 } 485 486 static int 487 newreno_beta_handler(SYSCTL_HANDLER_ARGS) 488 { 489 int error; 490 uint32_t new; 491 492 new = *(uint32_t *)arg1; 493 error = sysctl_handle_int(oidp, &new, 0, req); 494 if (error == 0 && req->newptr != NULL ) { 495 if (arg1 == &VNET_NAME(newreno_beta_ecn) && !V_cc_do_abe) 496 error = EACCES; 497 else if (new == 0 || new > 100) 498 error = EINVAL; 499 else 500 *(uint32_t *)arg1 = new; 501 } 502 503 return (error); 504 } 505 506 static void 507 newreno_newround(struct cc_var *ccv, uint32_t round_cnt) 508 { 509 struct newreno *nreno; 510 511 nreno = (struct newreno *)ccv->cc_data; 512 /* We have entered a new round */ 513 nreno->css_lastround_minrtt = nreno->css_current_round_minrtt; 514 nreno->css_current_round_minrtt = 0xffffffff; 515 nreno->css_rttsample_count = 0; 516 nreno->css_current_round = round_cnt; 517 if ((nreno->newreno_flags & CC_NEWRENO_HYSTART_IN_CSS) && 518 ((round_cnt - nreno->css_entered_at_round) >= hystart_css_rounds)) { 519 /* Enter CA */ 520 if (ccv->flags & CCF_HYSTART_CAN_SH_CWND) { 521 /* 522 * We engage more than snd_ssthresh, engage 523 * the brakes!! Though we will stay in SS to 524 * creep back up again, so lets leave CSS active 525 * and give us hystart_css_rounds more rounds. 526 */ 527 if (ccv->flags & CCF_HYSTART_CONS_SSTH) { 528 CCV(ccv, snd_ssthresh) = ((nreno->css_lowrtt_fas + nreno->css_fas_at_css_entry) / 2); 529 } else { 530 CCV(ccv, snd_ssthresh) = nreno->css_lowrtt_fas; 531 } 532 CCV(ccv, snd_cwnd) = nreno->css_fas_at_css_entry; 533 nreno->css_entered_at_round = round_cnt; 534 } else { 535 CCV(ccv, snd_ssthresh) = CCV(ccv, snd_cwnd); 536 /* Turn off the CSS flag */ 537 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 538 /* Disable use of CSS in the future except long idle */ 539 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_ENABLED; 540 } 541 newreno_log_hystart_event(ccv, nreno, 6, CCV(ccv, snd_ssthresh)); 542 } 543 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 544 newreno_log_hystart_event(ccv, nreno, 4, round_cnt); 545 } 546 547 static void 548 newreno_rttsample(struct cc_var *ccv, uint32_t usec_rtt, uint32_t rxtcnt, uint32_t fas) 549 { 550 struct newreno *nreno; 551 552 nreno = (struct newreno *)ccv->cc_data; 553 if (rxtcnt > 1) { 554 /* 555 * Only look at RTT's that are non-ambiguous. 556 */ 557 return; 558 } 559 nreno->css_rttsample_count++; 560 nreno->css_last_fas = fas; 561 if (nreno->css_current_round_minrtt > usec_rtt) { 562 nreno->css_current_round_minrtt = usec_rtt; 563 nreno->css_lowrtt_fas = nreno->css_last_fas; 564 } 565 if ((nreno->css_rttsample_count >= hystart_n_rttsamples) && 566 (nreno->css_current_round_minrtt != 0xffffffff) && 567 (nreno->css_current_round_minrtt < nreno->css_baseline_minrtt) && 568 (nreno->css_lastround_minrtt != 0xffffffff)) { 569 /* 570 * We were in CSS and the RTT is now less, we 571 * entered CSS erroneously. 572 */ 573 nreno->newreno_flags &= ~CC_NEWRENO_HYSTART_IN_CSS; 574 newreno_log_hystart_event(ccv, nreno, 8, nreno->css_baseline_minrtt); 575 nreno->css_baseline_minrtt = 0xffffffff; 576 } 577 if (nreno->newreno_flags & CC_NEWRENO_HYSTART_ENABLED) 578 newreno_log_hystart_event(ccv, nreno, 5, usec_rtt); 579 } 580 581 SYSCTL_DECL(_net_inet_tcp_cc_newreno); 582 SYSCTL_NODE(_net_inet_tcp_cc, OID_AUTO, newreno, 583 CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 584 "New Reno related settings"); 585 586 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta, 587 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 588 &VNET_NAME(newreno_beta), 3, &newreno_beta_handler, "IU", 589 "New Reno beta, specified as number between 1 and 100"); 590 591 SYSCTL_PROC(_net_inet_tcp_cc_newreno, OID_AUTO, beta_ecn, 592 CTLFLAG_VNET | CTLTYPE_UINT | CTLFLAG_RW | CTLFLAG_NEEDGIANT, 593 &VNET_NAME(newreno_beta_ecn), 3, &newreno_beta_handler, "IU", 594 "New Reno beta ecn, specified as number between 1 and 100"); 595 596 DECLARE_CC_MODULE(newreno, &newreno_cc_algo); 597 MODULE_VERSION(newreno, 2); 598