1 /* 2 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 3 * Copyright (c) 2003, 2004 The DragonFly Project. All rights reserved. 4 * 5 * This code is derived from software contributed to The DragonFly Project 6 * by Jeffrey M. Hsu. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 3. Neither the name of The DragonFly Project nor the names of its 17 * contributors may be used to endorse or promote products derived 18 * from this software without specific, prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 24 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 27 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 30 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $DragonFly: src/sys/netinet/tcp_sack.c,v 1.1 2004/11/14 00:49:08 hsu Exp $ 34 */ 35 36 /* 37 * Copyright (c) 2003, 2004 Jeffrey M. Hsu. All rights reserved. 38 * 39 * License terms: all terms for the DragonFly license above plus the following: 40 * 41 * 4. All advertising materials mentioning features or use of this software 42 * must display the following acknowledgement: 43 * 44 * This product includes software developed by Jeffrey M. Hsu 45 * for the DragonFly Project. 46 * 47 * This requirement may be waived with permission from Jeffrey Hsu. 48 * This requirement will sunset and may be removed on November 13, 2005, 49 * after which the standard DragonFly license (as shown above) will 50 * apply. 51 */ 52 53 #include <sys/param.h> 54 #include <sys/systm.h> 55 #include <sys/kernel.h> 56 #include <sys/malloc.h> 57 #include <sys/queue.h> 58 #include <sys/thread.h> 59 #include <sys/types.h> 60 #include <sys/socket.h> 61 #include <sys/socketvar.h> 62 63 #include <net/if.h> 64 65 #include <netinet/in.h> 66 #include <netinet/in_systm.h> 67 #include <netinet/ip.h> 68 #include <netinet/in_var.h> 69 #include <netinet/in_pcb.h> 70 #include <netinet/ip_var.h> 71 #include <netinet/tcp.h> 72 #include <netinet/tcp_seq.h> 73 #include <netinet/tcp_var.h> 74 75 #include <vm/vm_zone.h> 76 77 struct sackblock { 78 tcp_seq sblk_start; 79 tcp_seq sblk_end; 80 TAILQ_ENTRY(sackblock) sblk_list; 81 }; 82 83 #define MAXSAVEDBLOCKS 8 /* per connection limit */ 84 85 static void insert_block(struct scoreboard *scb, struct sackblock *newblock); 86 static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una, 87 u_int maxseg); 88 89 static vm_zone_t sackblock_zone; 90 91 /* 92 * Initialize SACK module. 93 */ 94 void 95 tcp_sack_init() 96 { 97 sackblock_zone = zinit("sack blocks", sizeof(struct sackblock), 98 maxsockets, ZONE_INTERRUPT, 0); 99 } 100 101 /* 102 * Per-tcpcb initialization. 103 */ 104 void 105 tcp_sack_tcpcb_init(struct tcpcb *tp) 106 { 107 struct scoreboard *scb = &tp->scb; 108 109 scb->nblocks = 0; 110 TAILQ_INIT(&scb->sackblocks); 111 scb->lastfound = NULL; 112 } 113 114 /* 115 * Find the SACK block containing or immediately preceding "seq". 116 * The boolean result indicates whether the sequence is actually 117 * contained in the SACK block. 118 */ 119 static boolean_t 120 sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb) 121 { 122 struct sackblock *hint = scb->lastfound; 123 struct sackblock *cur, *last, *prev; 124 125 if (TAILQ_EMPTY(&scb->sackblocks)) { 126 *sb = NULL; 127 return FALSE; 128 } 129 130 if (hint == NULL) { 131 /* No hint. Search from start to end. */ 132 cur = TAILQ_FIRST(&scb->sackblocks); 133 last = NULL; 134 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 135 } else { 136 if (SEQ_GEQ(seq, hint->sblk_start)) { 137 /* Search from hint to end of list. */ 138 cur = hint; 139 last = NULL; 140 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 141 } else { 142 /* Search from front of list to hint. */ 143 cur = TAILQ_FIRST(&scb->sackblocks); 144 last = hint; 145 prev = TAILQ_PREV(hint, sackblock_list, sblk_list); 146 } 147 } 148 149 do { 150 if (SEQ_GT(cur->sblk_end, seq)) { 151 if (SEQ_GEQ(seq, cur->sblk_start)) { 152 *sb = scb->lastfound = cur; 153 return TRUE; 154 } else { 155 *sb = scb->lastfound = 156 TAILQ_PREV(cur, sackblock_list, sblk_list); 157 return FALSE; 158 } 159 } 160 cur = TAILQ_NEXT(cur, sblk_list); 161 } while (cur != last); 162 163 *sb = scb->lastfound = prev; 164 return FALSE; 165 } 166 167 /* 168 * Allocate a SACK block. 169 */ 170 static __inline struct sackblock * 171 alloc_sackblock(void) 172 { 173 return zalloc(sackblock_zone); 174 } 175 176 /* 177 * Free a SACK block. 178 */ 179 static __inline void 180 free_sackblock(struct sackblock *s) 181 { 182 zfree(sackblock_zone, s); 183 } 184 185 /* 186 * Free up SACK blocks for data that's been acked. 187 */ 188 static void 189 tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack) 190 { 191 struct sackblock *sb, *nb; 192 193 sb = TAILQ_FIRST(&scb->sackblocks); 194 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) { 195 nb = TAILQ_NEXT(sb, sblk_list); 196 if (sb == scb->lastfound) 197 scb->lastfound = NULL; 198 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 199 free_sackblock(sb); 200 --scb->nblocks; 201 KASSERT(scb->nblocks >= 0, 202 ("SACK block count underflow: %d < 0", scb->nblocks)); 203 sb = nb; 204 } 205 if (sb && SEQ_GT(th_ack, sb->sblk_start)) 206 sb->sblk_start = th_ack; /* other side reneged? XXX */ 207 } 208 209 /* 210 * Delete and free SACK blocks saved in scoreboard. 211 */ 212 void 213 tcp_sack_cleanup(struct scoreboard *scb) 214 { 215 struct sackblock *sb, *nb; 216 217 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) { 218 free_sackblock(sb); 219 --scb->nblocks; 220 } 221 KASSERT(scb->nblocks == 0, 222 ("SACK block %d count not zero", scb->nblocks)); 223 TAILQ_INIT(&scb->sackblocks); 224 scb->lastfound = NULL; 225 } 226 227 /* 228 * Returns 0 if not D-SACK block, 229 * 1 if D-SACK, 230 * 2 if duplicate of out-of-order D-SACK block. 231 */ 232 int 233 tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks, 234 tcp_seq snd_una) 235 { 236 if (numblocks == 0) 237 return 0; 238 239 if (SEQ_LT(blocks[0].rblk_start, snd_una)) 240 return 1; 241 242 /* block 0 inside block 1 */ 243 if (numblocks > 1 && 244 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) && 245 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end)) 246 return 2; 247 248 return 0; 249 } 250 251 /* 252 * Update scoreboard on new incoming ACK. 253 */ 254 static void 255 tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to) 256 { 257 const int numblocks = to->to_nsackblocks; 258 struct raw_sackblock *blocks = to->to_sackblocks; 259 struct scoreboard *scb = &tp->scb; 260 struct sackblock *sb; 261 int startblock; 262 int i; 263 264 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0) 265 startblock = 1; 266 else 267 startblock = 0; 268 269 for (i = startblock; i < numblocks; i++) { 270 struct raw_sackblock *newsackblock = &blocks[i]; 271 272 /* don't accept bad SACK blocks */ 273 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) 274 break; /* skip all other blocks */ 275 276 sb = alloc_sackblock(); 277 if (sb == NULL) /* do some sort of cleanup? XXX */ 278 break; /* just skip rest of blocks */ 279 sb->sblk_start = newsackblock->rblk_start; 280 sb->sblk_end = newsackblock->rblk_end; 281 if (TAILQ_EMPTY(&scb->sackblocks)) { 282 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks")); 283 scb->nblocks = 1; 284 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list); 285 } else { 286 insert_block(scb, sb); 287 } 288 } 289 } 290 291 void 292 tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to) 293 { 294 struct scoreboard *scb = &tp->scb; 295 296 tcp_sack_ack_blocks(scb, tp->snd_una); 297 tcp_sack_add_blocks(tp, to); 298 update_lostseq(scb, tp->snd_una, tp->t_maxseg); 299 if (SEQ_LT(tp->rexmt_high, tp->snd_una)) 300 tp->rexmt_high = tp->snd_una; 301 } 302 303 /* 304 * Insert SACK block into sender's scoreboard. 305 */ 306 static void 307 insert_block(struct scoreboard *scb, struct sackblock *newblock) 308 { 309 struct sackblock *sb, *workingblock; 310 boolean_t overlap_front; 311 312 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks")); 313 314 if (scb->nblocks == MAXSAVEDBLOCKS) { 315 /* 316 * Should try to kick out older blocks XXX JH 317 * May be able to coalesce with existing block. 318 * Or, go other way and free all blocks if we hit this limit. 319 */ 320 free_sackblock(newblock); 321 return; 322 } 323 KASSERT(scb->nblocks < MAXSAVEDBLOCKS, 324 ("too many SACK blocks %d", scb->nblocks)); 325 326 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb); 327 328 if (sb == NULL) { 329 workingblock = newblock; 330 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list); 331 ++scb->nblocks; 332 } else { 333 if (overlap_front || sb->sblk_end == newblock->sblk_start) { 334 /* extend old block and discard new one */ 335 workingblock = sb; 336 if (SEQ_GT(newblock->sblk_end, sb->sblk_end)) 337 sb->sblk_end = newblock->sblk_end; 338 free_sackblock(newblock); 339 } else { 340 workingblock = newblock; 341 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock, 342 sblk_list); 343 ++scb->nblocks; 344 } 345 } 346 347 /* Consolidate right-hand side. */ 348 sb = TAILQ_NEXT(workingblock, sblk_list); 349 while (sb != NULL && 350 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) { 351 struct sackblock *nextblock; 352 353 nextblock = TAILQ_NEXT(sb, sblk_list); 354 /* Remove completely overlapped block */ 355 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 356 free_sackblock(sb); 357 --scb->nblocks; 358 KASSERT(scb->nblocks > 0, 359 ("removed overlapped block: %d blocks left", scb->nblocks)); 360 sb = nextblock; 361 } 362 if (sb != NULL && 363 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) { 364 /* Extend new block to cover partially overlapped old block. */ 365 workingblock->sblk_end = sb->sblk_end; 366 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 367 free_sackblock(sb); 368 --scb->nblocks; 369 KASSERT(scb->nblocks > 0, 370 ("removed partial right: %d blocks left", scb->nblocks)); 371 } 372 } 373 374 #ifdef DEBUG_SACK_BLOCKS 375 static void 376 tcp_sack_dump_blocks(struct scoreboard *scb) 377 { 378 struct sackblock *sb; 379 380 printf("%d blocks:", scb->nblocks); 381 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 382 printf(" [%u, %u)", sb->sblk_start, sb->sblk_end); 383 printf("\n"); 384 } 385 #else 386 static __inline void 387 tcp_sack_dump_blocks(struct scoreboard *scb) 388 { 389 } 390 #endif 391 392 /* 393 * Optimization to quickly determine which packets are lost. 394 */ 395 static void 396 update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg) 397 { 398 struct sackblock *sb; 399 int nsackblocks = 0; 400 int bytes_sacked = 0; 401 402 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list); 403 while (sb != NULL) { 404 ++nsackblocks; 405 bytes_sacked += sb->sblk_end - sb->sblk_start; 406 if (nsackblocks == tcprexmtthresh || 407 bytes_sacked >= tcprexmtthresh * maxseg) { 408 scb->lostseq = sb->sblk_start; 409 return; 410 } 411 sb = TAILQ_PREV(sb, sackblock_list, sblk_list); 412 } 413 scb->lostseq = snd_una; 414 } 415 416 /* 417 * Return whether the given sequence number is considered lost. 418 */ 419 static boolean_t 420 scb_islost(struct scoreboard *scb, tcp_seq seqnum) 421 { 422 return SEQ_LT(seqnum, scb->lostseq); 423 } 424 425 /* 426 * True if at least "amount" has been SACKed. Used by Early Retransmit. 427 */ 428 boolean_t 429 tcp_sack_has_sacked(struct scoreboard *scb, u_int amount) 430 { 431 struct sackblock *sb; 432 int bytes_sacked = 0; 433 434 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 435 bytes_sacked += sb->sblk_end - sb->sblk_start; 436 if (bytes_sacked >= amount) 437 return TRUE; 438 } 439 return FALSE; 440 } 441 442 /* 443 * Return estimate of the number of bytes outstanding in the network. 444 */ 445 uint32_t 446 tcp_sack_compute_pipe(struct tcpcb *tp) 447 { 448 struct scoreboard *scb = &tp->scb; 449 struct sackblock *sb; 450 int nlost, nretransmitted; 451 tcp_seq end; 452 453 nlost = tp->snd_max - scb->lostseq; 454 nretransmitted = tp->rexmt_high - tp->snd_una; 455 456 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 457 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) { 458 end = seq_min(sb->sblk_end, tp->rexmt_high); 459 nretransmitted -= end - sb->sblk_start; 460 } 461 if (SEQ_GEQ(sb->sblk_start, scb->lostseq)) 462 nlost -= sb->sblk_end - sb->sblk_start; 463 } 464 465 return (nlost + nretransmitted); 466 } 467 468 /* 469 * Return the sequence number and length of the next segment to transmit 470 * when in Fast Recovery. 471 */ 472 boolean_t 473 tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen, 474 boolean_t *lostdup) 475 { 476 struct scoreboard *scb = &tp->scb; 477 struct socket *so = tp->t_inpcb->inp_socket; 478 struct sackblock *sb; 479 const struct sackblock *lastblock = 480 TAILQ_LAST(&scb->sackblocks, sackblock_list); 481 tcp_seq torexmt; 482 long len, off; 483 484 /* skip SACKed data */ 485 tcp_sack_skip_sacked(scb, &tp->rexmt_high); 486 487 /* Look for lost data. */ 488 torexmt = tp->rexmt_high; 489 *lostdup = FALSE; 490 if (lastblock != NULL) { 491 if (SEQ_LT(torexmt, lastblock->sblk_end) && 492 scb_islost(scb, torexmt)) { 493 sendunsacked: 494 *nextrexmt = torexmt; 495 /* If the left-hand edge has been SACKed, pull it in. */ 496 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb)) 497 *plen = sb->sblk_start - torexmt; 498 else 499 *plen = tp->t_maxseg; 500 return TRUE; 501 } 502 } 503 504 /* See if unsent data available within send window. */ 505 off = tp->snd_max - tp->snd_una; 506 len = (long) ulmin(so->so_snd.sb_cc, tp->snd_wnd) - off; 507 if (len > 0) { 508 *nextrexmt = tp->snd_max; /* Send new data. */ 509 *plen = tp->t_maxseg; 510 return TRUE; 511 } 512 513 /* We're less certain this data has been lost. */ 514 if (lastblock == NULL || SEQ_LT(torexmt, lastblock->sblk_end)) 515 goto sendunsacked; 516 517 return FALSE; 518 } 519 520 /* 521 * Return the next sequence number higher than "*prexmt" that has 522 * not been SACKed. 523 */ 524 void 525 tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt) 526 { 527 struct sackblock *sb; 528 529 /* skip SACKed data */ 530 if (sack_block_lookup(scb, *prexmt, &sb)) 531 *prexmt = sb->sblk_end; 532 } 533 534 #ifdef later 535 void 536 tcp_sack_save_scoreboard(struct scoreboard *scb) 537 { 538 struct scoreboard *scb = &tp->scb; 539 540 scb->sackblocks_prev = scb->sackblocks; 541 TAILQ_INIT(&scb->sackblocks); 542 } 543 544 void 545 tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una, 546 u_int maxseg) 547 { 548 struct sackblock *sb; 549 550 scb->sackblocks = scb->sackblocks_prev; 551 scb->nblocks = 0; 552 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 553 ++scb->nblocks; 554 tcp_sack_ack_blocks(scb, snd_una); 555 scb->lastfound = NULL; 556 } 557 #endif 558 559 #ifdef DEBUG_SACK_HISTORY 560 static void 561 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 562 { 563 int i; 564 static int ndumped; 565 566 /* only need a couple of these to debug most problems */ 567 if (++ndumped > 900) 568 return; 569 570 printf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory); 571 for (i = 0; i < tp->nsackhistory; ++i) 572 printf("[%u, %u) ", tp->sackhistory[i].rblk_start, 573 tp->sackhistory[i].rblk_end); 574 printf("\n"); 575 } 576 #else 577 static __inline void 578 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 579 { 580 } 581 #endif 582 583 /* 584 * Remove old SACK blocks from the SACK history that have already been ACKed. 585 */ 586 static void 587 tcp_sack_ack_history(struct tcpcb *tp) 588 { 589 int i, nblocks, openslot; 590 591 tcp_sack_dump_history("before tcp_sack_ack_history", tp); 592 nblocks = tp->nsackhistory; 593 for (i = openslot = 0; i < nblocks; ++i) { 594 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) { 595 --tp->nsackhistory; 596 continue; 597 } 598 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt)) 599 tp->sackhistory[i].rblk_start = tp->rcv_nxt; 600 if (i == openslot) 601 ++openslot; 602 else 603 tp->sackhistory[openslot++] = tp->sackhistory[i]; 604 } 605 tcp_sack_dump_history("after tcp_sack_ack_history", tp); 606 KASSERT(openslot == tp->nsackhistory, 607 ("tcp_sack_ack_history miscounted: %d != %d", 608 openslot, tp->nsackhistory)); 609 } 610 611 /* 612 * Add or merge newblock into reported history. 613 * Also remove or update SACK blocks that will be acked. 614 */ 615 static void 616 tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end) 617 { 618 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS]; 619 int i, cindex; 620 621 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp); 622 /* 623 * Six cases: 624 * 0) no overlap 625 * 1) newblock == oldblock 626 * 2) oldblock contains newblock 627 * 3) newblock contains oldblock 628 * 4) tail of oldblock overlaps or abuts start of newblock 629 * 5) tail of newblock overlaps or abuts head of oldblock 630 */ 631 for (i = cindex = 0; i < tp->nsackhistory; ++i) { 632 struct raw_sackblock *oldblock = &tp->sackhistory[i]; 633 tcp_seq old_start = oldblock->rblk_start; 634 tcp_seq old_end = oldblock->rblk_end; 635 636 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) { 637 /* Case 0: no overlap. Copy old block. */ 638 copy[cindex++] = *oldblock; 639 continue; 640 } 641 642 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) { 643 /* Cases 1 & 2. Move block to front of history. */ 644 int j; 645 646 start = old_start; 647 end = old_end; 648 /* no need to check rest of blocks */ 649 for (j = i + 1; j < tp->nsackhistory; ++j) 650 copy[cindex++] = tp->sackhistory[j]; 651 break; 652 } 653 654 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) { 655 /* Case 4: extend start of new block. */ 656 start = old_start; 657 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) { 658 /* Case 5: extend end of new block */ 659 end = old_end; 660 } else { 661 /* Case 3. Delete old block by not copying it. */ 662 KASSERT(SEQ_LEQ(start, old_start) && 663 SEQ_GEQ(end, old_end), 664 ("bad logic: old [%u, %u), new [%u, %u)", 665 old_start, old_end, start, end)); 666 } 667 } 668 669 /* insert new block */ 670 tp->sackhistory[0].rblk_start = start; 671 tp->sackhistory[0].rblk_end = end; 672 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1); 673 for (i = 0; i < cindex; ++i) 674 tp->sackhistory[i + 1] = copy[i]; 675 tp->nsackhistory = cindex + 1; 676 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp); 677 } 678 679 /* 680 * Fill in SACK report to return to data sender. 681 */ 682 void 683 tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen) 684 { 685 u_int optlen = *plen; 686 uint32_t *lp = (uint32_t *)(opt + optlen); 687 uint32_t *olp; 688 tcp_seq hstart = tp->rcv_nxt, hend; 689 int nblocks; 690 691 KASSERT(TCP_MAXOLEN - optlen >= 692 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK, 693 ("no room for SACK header and one block: optlen %d", optlen)); 694 695 olp = lp++; 696 optlen += TCPOLEN_SACK_ALIGNED; 697 698 tcp_sack_ack_history(tp); 699 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) { 700 *lp++ = htonl(tp->reportblk.rblk_start); 701 *lp++ = htonl(tp->reportblk.rblk_end); 702 optlen += TCPOLEN_SACK_BLOCK; 703 hstart = tp->reportblk.rblk_start; 704 hend = tp->reportblk.rblk_end; 705 if (tp->t_flags & TF_ENCLOSESEG) { 706 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK, 707 ("no room for enclosing SACK block: oplen %d", 708 optlen)); 709 *lp++ = htonl(tp->encloseblk.rblk_start); 710 *lp++ = htonl(tp->encloseblk.rblk_end); 711 optlen += TCPOLEN_SACK_BLOCK; 712 hstart = tp->encloseblk.rblk_start; 713 hend = tp->encloseblk.rblk_end; 714 } 715 if (SEQ_GT(hstart, tp->rcv_nxt)) 716 tcp_sack_update_reported_history(tp, hstart, hend); 717 } 718 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) { 719 /* Fill in from left! Walk re-assembly queue. */ 720 struct tseg_qent *q; 721 722 q = LIST_FIRST(&tp->t_segq); 723 while (q != NULL && 724 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 725 *lp++ = htonl(q->tqe_th->th_seq); 726 *lp++ = htonl(q->tqe_th->th_seq + q->tqe_len); 727 optlen += TCPOLEN_SACK_BLOCK; 728 q = LIST_NEXT(q, tqe_q); 729 } 730 } else { 731 int n = 0; 732 733 /* Fill in SACK blocks from right side. */ 734 while (n < tp->nsackhistory && 735 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 736 if (tp->sackhistory[n].rblk_start != hstart) { 737 *lp++ = htonl(tp->sackhistory[n].rblk_start); 738 *lp++ = htonl(tp->sackhistory[n].rblk_end); 739 optlen += TCPOLEN_SACK_BLOCK; 740 } 741 ++n; 742 } 743 } 744 tp->reportblk.rblk_start = tp->reportblk.rblk_end; 745 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT); 746 nblocks = (lp - olp - 1) / 2; 747 *olp = htonl(TCPOPT_SACK_ALIGNED | 748 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK)); 749 *plen = optlen; 750 } 751