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 1.6 2007/04/22 01:13:14 dillon Exp $ 34 */ 35 36 #include <sys/param.h> 37 #include <sys/systm.h> 38 #include <sys/kernel.h> 39 #include <sys/malloc.h> 40 #include <sys/queue.h> 41 #include <sys/thread.h> 42 #include <sys/types.h> 43 #include <sys/socket.h> 44 #include <sys/socketvar.h> 45 46 #include <net/if.h> 47 48 #include <netinet/in.h> 49 #include <netinet/in_systm.h> 50 #include <netinet/ip.h> 51 #include <netinet/in_var.h> 52 #include <netinet/in_pcb.h> 53 #include <netinet/ip_var.h> 54 #include <netinet/tcp.h> 55 #include <netinet/tcp_seq.h> 56 #include <netinet/tcp_var.h> 57 58 #include <vm/vm_zone.h> 59 60 struct sackblock { 61 tcp_seq sblk_start; 62 tcp_seq sblk_end; 63 TAILQ_ENTRY(sackblock) sblk_list; 64 }; 65 66 #define MAXSAVEDBLOCKS 8 /* per connection limit */ 67 68 static void insert_block(struct scoreboard *scb, struct sackblock *newblock); 69 static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una, 70 u_int maxseg); 71 72 static vm_zone_t sackblock_zone; 73 74 /* 75 * Initialize SACK module. 76 */ 77 void 78 tcp_sack_init(void) 79 { 80 sackblock_zone = zinit("sack blocks", sizeof(struct sackblock), 81 maxsockets, ZONE_INTERRUPT, 0); 82 } 83 84 /* 85 * Per-tcpcb initialization. 86 */ 87 void 88 tcp_sack_tcpcb_init(struct tcpcb *tp) 89 { 90 struct scoreboard *scb = &tp->scb; 91 92 scb->nblocks = 0; 93 TAILQ_INIT(&scb->sackblocks); 94 scb->lastfound = NULL; 95 } 96 97 /* 98 * Find the SACK block containing or immediately preceding "seq". 99 * The boolean result indicates whether the sequence is actually 100 * contained in the SACK block. 101 */ 102 static boolean_t 103 sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb) 104 { 105 struct sackblock *hint = scb->lastfound; 106 struct sackblock *cur, *last, *prev; 107 108 if (TAILQ_EMPTY(&scb->sackblocks)) { 109 *sb = NULL; 110 return FALSE; 111 } 112 113 if (hint == NULL) { 114 /* No hint. Search from start to end. */ 115 cur = TAILQ_FIRST(&scb->sackblocks); 116 last = NULL; 117 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 118 } else { 119 if (SEQ_GEQ(seq, hint->sblk_start)) { 120 /* Search from hint to end of list. */ 121 cur = hint; 122 last = NULL; 123 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 124 } else { 125 /* Search from front of list to hint. */ 126 cur = TAILQ_FIRST(&scb->sackblocks); 127 last = hint; 128 prev = TAILQ_PREV(hint, sackblock_list, sblk_list); 129 } 130 } 131 132 do { 133 if (SEQ_GT(cur->sblk_end, seq)) { 134 if (SEQ_GEQ(seq, cur->sblk_start)) { 135 *sb = scb->lastfound = cur; 136 return TRUE; 137 } else { 138 *sb = scb->lastfound = 139 TAILQ_PREV(cur, sackblock_list, sblk_list); 140 return FALSE; 141 } 142 } 143 cur = TAILQ_NEXT(cur, sblk_list); 144 } while (cur != last); 145 146 *sb = scb->lastfound = prev; 147 return FALSE; 148 } 149 150 /* 151 * Allocate a SACK block. 152 */ 153 static __inline struct sackblock * 154 alloc_sackblock(void) 155 { 156 return zalloc(sackblock_zone); 157 } 158 159 /* 160 * Free a SACK block. 161 */ 162 static __inline void 163 free_sackblock(struct sackblock *s) 164 { 165 zfree(sackblock_zone, s); 166 } 167 168 /* 169 * Free up SACK blocks for data that's been acked. 170 */ 171 static void 172 tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack) 173 { 174 struct sackblock *sb, *nb; 175 176 sb = TAILQ_FIRST(&scb->sackblocks); 177 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) { 178 nb = TAILQ_NEXT(sb, sblk_list); 179 if (sb == scb->lastfound) 180 scb->lastfound = NULL; 181 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 182 free_sackblock(sb); 183 --scb->nblocks; 184 KASSERT(scb->nblocks >= 0, 185 ("SACK block count underflow: %d < 0", scb->nblocks)); 186 sb = nb; 187 } 188 if (sb && SEQ_GT(th_ack, sb->sblk_start)) 189 sb->sblk_start = th_ack; /* other side reneged? XXX */ 190 } 191 192 /* 193 * Delete and free SACK blocks saved in scoreboard. 194 */ 195 void 196 tcp_sack_cleanup(struct scoreboard *scb) 197 { 198 struct sackblock *sb, *nb; 199 200 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) { 201 free_sackblock(sb); 202 --scb->nblocks; 203 } 204 KASSERT(scb->nblocks == 0, 205 ("SACK block %d count not zero", scb->nblocks)); 206 TAILQ_INIT(&scb->sackblocks); 207 scb->lastfound = NULL; 208 } 209 210 /* 211 * Returns 0 if not D-SACK block, 212 * 1 if D-SACK, 213 * 2 if duplicate of out-of-order D-SACK block. 214 */ 215 int 216 tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks, 217 tcp_seq snd_una) 218 { 219 if (numblocks == 0) 220 return 0; 221 222 if (SEQ_LT(blocks[0].rblk_start, snd_una)) 223 return 1; 224 225 /* block 0 inside block 1 */ 226 if (numblocks > 1 && 227 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) && 228 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end)) 229 return 2; 230 231 return 0; 232 } 233 234 /* 235 * Update scoreboard on new incoming ACK. 236 */ 237 static void 238 tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to) 239 { 240 const int numblocks = to->to_nsackblocks; 241 struct raw_sackblock *blocks = to->to_sackblocks; 242 struct scoreboard *scb = &tp->scb; 243 struct sackblock *sb; 244 int startblock; 245 int i; 246 247 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0) 248 startblock = 1; 249 else 250 startblock = 0; 251 252 for (i = startblock; i < numblocks; i++) { 253 struct raw_sackblock *newsackblock = &blocks[i]; 254 255 /* don't accept bad SACK blocks */ 256 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) 257 break; /* skip all other blocks */ 258 259 sb = alloc_sackblock(); 260 if (sb == NULL) /* do some sort of cleanup? XXX */ 261 break; /* just skip rest of blocks */ 262 sb->sblk_start = newsackblock->rblk_start; 263 sb->sblk_end = newsackblock->rblk_end; 264 if (TAILQ_EMPTY(&scb->sackblocks)) { 265 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks")); 266 scb->nblocks = 1; 267 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list); 268 } else { 269 insert_block(scb, sb); 270 } 271 } 272 } 273 274 void 275 tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to) 276 { 277 struct scoreboard *scb = &tp->scb; 278 279 tcp_sack_ack_blocks(scb, tp->snd_una); 280 tcp_sack_add_blocks(tp, to); 281 update_lostseq(scb, tp->snd_una, tp->t_maxseg); 282 if (SEQ_LT(tp->rexmt_high, tp->snd_una)) 283 tp->rexmt_high = tp->snd_una; 284 } 285 286 /* 287 * Insert SACK block into sender's scoreboard. 288 */ 289 static void 290 insert_block(struct scoreboard *scb, struct sackblock *newblock) 291 { 292 struct sackblock *sb, *workingblock; 293 boolean_t overlap_front; 294 295 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks")); 296 297 if (scb->nblocks == MAXSAVEDBLOCKS) { 298 /* 299 * Should try to kick out older blocks XXX JH 300 * May be able to coalesce with existing block. 301 * Or, go other way and free all blocks if we hit this limit. 302 */ 303 free_sackblock(newblock); 304 return; 305 } 306 KASSERT(scb->nblocks < MAXSAVEDBLOCKS, 307 ("too many SACK blocks %d", scb->nblocks)); 308 309 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb); 310 311 if (sb == NULL) { 312 workingblock = newblock; 313 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list); 314 ++scb->nblocks; 315 } else { 316 if (overlap_front || sb->sblk_end == newblock->sblk_start) { 317 /* extend old block and discard new one */ 318 workingblock = sb; 319 if (SEQ_GT(newblock->sblk_end, sb->sblk_end)) 320 sb->sblk_end = newblock->sblk_end; 321 free_sackblock(newblock); 322 } else { 323 workingblock = newblock; 324 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock, 325 sblk_list); 326 ++scb->nblocks; 327 } 328 } 329 330 /* Consolidate right-hand side. */ 331 sb = TAILQ_NEXT(workingblock, sblk_list); 332 while (sb != NULL && 333 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) { 334 struct sackblock *nextblock; 335 336 nextblock = TAILQ_NEXT(sb, sblk_list); 337 /* Remove completely overlapped block */ 338 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 339 free_sackblock(sb); 340 --scb->nblocks; 341 KASSERT(scb->nblocks > 0, 342 ("removed overlapped block: %d blocks left", scb->nblocks)); 343 sb = nextblock; 344 } 345 if (sb != NULL && 346 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) { 347 /* Extend new block to cover partially overlapped old block. */ 348 workingblock->sblk_end = sb->sblk_end; 349 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 350 free_sackblock(sb); 351 --scb->nblocks; 352 KASSERT(scb->nblocks > 0, 353 ("removed partial right: %d blocks left", scb->nblocks)); 354 } 355 } 356 357 #ifdef DEBUG_SACK_BLOCKS 358 static void 359 tcp_sack_dump_blocks(struct scoreboard *scb) 360 { 361 struct sackblock *sb; 362 363 kprintf("%d blocks:", scb->nblocks); 364 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 365 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end); 366 kprintf("\n"); 367 } 368 #else 369 static __inline void 370 tcp_sack_dump_blocks(struct scoreboard *scb) 371 { 372 } 373 #endif 374 375 /* 376 * Optimization to quickly determine which packets are lost. 377 */ 378 static void 379 update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg) 380 { 381 struct sackblock *sb; 382 int nsackblocks = 0; 383 int bytes_sacked = 0; 384 385 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list); 386 while (sb != NULL) { 387 ++nsackblocks; 388 bytes_sacked += sb->sblk_end - sb->sblk_start; 389 if (nsackblocks == tcprexmtthresh || 390 bytes_sacked >= tcprexmtthresh * maxseg) { 391 scb->lostseq = sb->sblk_start; 392 return; 393 } 394 sb = TAILQ_PREV(sb, sackblock_list, sblk_list); 395 } 396 scb->lostseq = snd_una; 397 } 398 399 /* 400 * Return whether the given sequence number is considered lost. 401 */ 402 static boolean_t 403 scb_islost(struct scoreboard *scb, tcp_seq seqnum) 404 { 405 return SEQ_LT(seqnum, scb->lostseq); 406 } 407 408 /* 409 * True if at least "amount" has been SACKed. Used by Early Retransmit. 410 */ 411 boolean_t 412 tcp_sack_has_sacked(struct scoreboard *scb, u_int amount) 413 { 414 struct sackblock *sb; 415 int bytes_sacked = 0; 416 417 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 418 bytes_sacked += sb->sblk_end - sb->sblk_start; 419 if (bytes_sacked >= amount) 420 return TRUE; 421 } 422 return FALSE; 423 } 424 425 /* 426 * Number of bytes SACKed below seq. 427 */ 428 int 429 tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq) 430 { 431 struct sackblock *sb; 432 int bytes_sacked = 0; 433 434 sb = TAILQ_FIRST(&scb->sackblocks); 435 while (sb && SEQ_GT(seq, sb->sblk_start)) { 436 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start; 437 sb = TAILQ_NEXT(sb, sblk_list); 438 } 439 return bytes_sacked; 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.ssb_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 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory); 571 for (i = 0; i < tp->nsackhistory; ++i) 572 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start, 573 tp->sackhistory[i].rblk_end); 574 kprintf("\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