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 1.8 2008/08/15 21:37:16 nth 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 struct sackblock { 59 tcp_seq sblk_start; 60 tcp_seq sblk_end; 61 TAILQ_ENTRY(sackblock) sblk_list; 62 }; 63 64 #define MAXSAVEDBLOCKS 8 /* per connection limit */ 65 66 static void insert_block(struct scoreboard *scb, struct sackblock *newblock); 67 static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una, 68 u_int maxseg); 69 70 static MALLOC_DEFINE(M_SACKBLOCK, "sblk", "sackblock struct"); 71 72 /* 73 * Per-tcpcb initialization. 74 */ 75 void 76 tcp_sack_tcpcb_init(struct tcpcb *tp) 77 { 78 struct scoreboard *scb = &tp->scb; 79 80 scb->nblocks = 0; 81 TAILQ_INIT(&scb->sackblocks); 82 scb->lastfound = NULL; 83 } 84 85 /* 86 * Find the SACK block containing or immediately preceding "seq". 87 * The boolean result indicates whether the sequence is actually 88 * contained in the SACK block. 89 */ 90 static boolean_t 91 sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb) 92 { 93 struct sackblock *hint = scb->lastfound; 94 struct sackblock *cur, *last, *prev; 95 96 if (TAILQ_EMPTY(&scb->sackblocks)) { 97 *sb = NULL; 98 return FALSE; 99 } 100 101 if (hint == NULL) { 102 /* No hint. Search from start to end. */ 103 cur = TAILQ_FIRST(&scb->sackblocks); 104 last = NULL; 105 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 106 } else { 107 if (SEQ_GEQ(seq, hint->sblk_start)) { 108 /* Search from hint to end of list. */ 109 cur = hint; 110 last = NULL; 111 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 112 } else { 113 /* Search from front of list to hint. */ 114 cur = TAILQ_FIRST(&scb->sackblocks); 115 last = hint; 116 prev = TAILQ_PREV(hint, sackblock_list, sblk_list); 117 } 118 } 119 120 do { 121 if (SEQ_GT(cur->sblk_end, seq)) { 122 if (SEQ_GEQ(seq, cur->sblk_start)) { 123 *sb = scb->lastfound = cur; 124 return TRUE; 125 } else { 126 *sb = scb->lastfound = 127 TAILQ_PREV(cur, sackblock_list, sblk_list); 128 return FALSE; 129 } 130 } 131 cur = TAILQ_NEXT(cur, sblk_list); 132 } while (cur != last); 133 134 *sb = scb->lastfound = prev; 135 return FALSE; 136 } 137 138 /* 139 * Allocate a SACK block. 140 */ 141 static __inline struct sackblock * 142 alloc_sackblock(void) 143 { 144 return (kmalloc(sizeof(struct sackblock), M_SACKBLOCK, M_NOWAIT)); 145 } 146 147 /* 148 * Free a SACK block. 149 */ 150 static __inline void 151 free_sackblock(struct sackblock *s) 152 { 153 kfree(s, M_SACKBLOCK); 154 } 155 156 /* 157 * Free up SACK blocks for data that's been acked. 158 */ 159 static void 160 tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack) 161 { 162 struct sackblock *sb, *nb; 163 164 sb = TAILQ_FIRST(&scb->sackblocks); 165 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) { 166 nb = TAILQ_NEXT(sb, sblk_list); 167 if (scb->lastfound == sb) 168 scb->lastfound = NULL; 169 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 170 free_sackblock(sb); 171 --scb->nblocks; 172 KASSERT(scb->nblocks >= 0, 173 ("SACK block count underflow: %d < 0", scb->nblocks)); 174 sb = nb; 175 } 176 if (sb && SEQ_GT(th_ack, sb->sblk_start)) 177 sb->sblk_start = th_ack; /* other side reneged? XXX */ 178 } 179 180 /* 181 * Delete and free SACK blocks saved in scoreboard. 182 */ 183 void 184 tcp_sack_cleanup(struct scoreboard *scb) 185 { 186 struct sackblock *sb, *nb; 187 188 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) { 189 free_sackblock(sb); 190 --scb->nblocks; 191 } 192 KASSERT(scb->nblocks == 0, 193 ("SACK block %d count not zero", scb->nblocks)); 194 TAILQ_INIT(&scb->sackblocks); 195 scb->lastfound = NULL; 196 } 197 198 /* 199 * Returns 0 if not D-SACK block, 200 * 1 if D-SACK, 201 * 2 if duplicate of out-of-order D-SACK block. 202 */ 203 int 204 tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks, 205 tcp_seq snd_una) 206 { 207 if (numblocks == 0) 208 return 0; 209 210 if (SEQ_LT(blocks[0].rblk_start, snd_una)) 211 return 1; 212 213 /* block 0 inside block 1 */ 214 if (numblocks > 1 && 215 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) && 216 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end)) 217 return 2; 218 219 return 0; 220 } 221 222 /* 223 * Update scoreboard on new incoming ACK. 224 */ 225 static void 226 tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to) 227 { 228 const int numblocks = to->to_nsackblocks; 229 struct raw_sackblock *blocks = to->to_sackblocks; 230 struct scoreboard *scb = &tp->scb; 231 struct sackblock *sb; 232 int startblock; 233 int i; 234 235 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0) 236 startblock = 1; 237 else 238 startblock = 0; 239 240 for (i = startblock; i < numblocks; i++) { 241 struct raw_sackblock *newsackblock = &blocks[i]; 242 243 /* don't accept bad SACK blocks */ 244 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) 245 break; /* skip all other blocks */ 246 247 sb = alloc_sackblock(); 248 if (sb == NULL) /* do some sort of cleanup? XXX */ 249 break; /* just skip rest of blocks */ 250 sb->sblk_start = newsackblock->rblk_start; 251 sb->sblk_end = newsackblock->rblk_end; 252 if (TAILQ_EMPTY(&scb->sackblocks)) { 253 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks")); 254 scb->nblocks = 1; 255 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list); 256 } else { 257 insert_block(scb, sb); 258 } 259 } 260 } 261 262 void 263 tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to) 264 { 265 struct scoreboard *scb = &tp->scb; 266 267 tcp_sack_ack_blocks(scb, tp->snd_una); 268 tcp_sack_add_blocks(tp, to); 269 update_lostseq(scb, tp->snd_una, tp->t_maxseg); 270 if (SEQ_LT(tp->rexmt_high, tp->snd_una)) 271 tp->rexmt_high = tp->snd_una; 272 } 273 274 /* 275 * Insert SACK block into sender's scoreboard. 276 */ 277 static void 278 insert_block(struct scoreboard *scb, struct sackblock *newblock) 279 { 280 struct sackblock *sb, *workingblock; 281 boolean_t overlap_front; 282 283 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks")); 284 285 if (scb->nblocks == MAXSAVEDBLOCKS) { 286 /* 287 * Should try to kick out older blocks XXX JH 288 * May be able to coalesce with existing block. 289 * Or, go other way and free all blocks if we hit this limit. 290 */ 291 free_sackblock(newblock); 292 return; 293 } 294 KASSERT(scb->nblocks < MAXSAVEDBLOCKS, 295 ("too many SACK blocks %d", scb->nblocks)); 296 297 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb); 298 299 if (sb == NULL) { 300 workingblock = newblock; 301 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list); 302 ++scb->nblocks; 303 } else { 304 if (overlap_front || sb->sblk_end == newblock->sblk_start) { 305 /* extend old block and discard new one */ 306 workingblock = sb; 307 if (SEQ_GT(newblock->sblk_end, sb->sblk_end)) 308 sb->sblk_end = newblock->sblk_end; 309 free_sackblock(newblock); 310 } else { 311 workingblock = newblock; 312 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock, 313 sblk_list); 314 ++scb->nblocks; 315 } 316 } 317 318 /* Consolidate right-hand side. */ 319 sb = TAILQ_NEXT(workingblock, sblk_list); 320 while (sb != NULL && 321 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) { 322 struct sackblock *nextblock; 323 324 nextblock = TAILQ_NEXT(sb, sblk_list); 325 if (scb->lastfound == sb) 326 scb->lastfound = NULL; 327 /* Remove completely overlapped block */ 328 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 329 free_sackblock(sb); 330 --scb->nblocks; 331 KASSERT(scb->nblocks > 0, 332 ("removed overlapped block: %d blocks left", scb->nblocks)); 333 sb = nextblock; 334 } 335 if (sb != NULL && 336 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) { 337 /* Extend new block to cover partially overlapped old block. */ 338 workingblock->sblk_end = sb->sblk_end; 339 if (scb->lastfound == sb) 340 scb->lastfound = NULL; 341 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 342 free_sackblock(sb); 343 --scb->nblocks; 344 KASSERT(scb->nblocks > 0, 345 ("removed partial right: %d blocks left", scb->nblocks)); 346 } 347 } 348 349 #ifdef DEBUG_SACK_BLOCKS 350 static void 351 tcp_sack_dump_blocks(struct scoreboard *scb) 352 { 353 struct sackblock *sb; 354 355 kprintf("%d blocks:", scb->nblocks); 356 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 357 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end); 358 kprintf("\n"); 359 } 360 #else 361 static __inline void 362 tcp_sack_dump_blocks(struct scoreboard *scb) 363 { 364 } 365 #endif 366 367 /* 368 * Optimization to quickly determine which packets are lost. 369 */ 370 static void 371 update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg) 372 { 373 struct sackblock *sb; 374 int nsackblocks = 0; 375 int bytes_sacked = 0; 376 377 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list); 378 while (sb != NULL) { 379 ++nsackblocks; 380 bytes_sacked += sb->sblk_end - sb->sblk_start; 381 if (nsackblocks == tcprexmtthresh || 382 bytes_sacked >= tcprexmtthresh * maxseg) { 383 scb->lostseq = sb->sblk_start; 384 return; 385 } 386 sb = TAILQ_PREV(sb, sackblock_list, sblk_list); 387 } 388 scb->lostseq = snd_una; 389 } 390 391 /* 392 * Return whether the given sequence number is considered lost. 393 */ 394 static boolean_t 395 scb_islost(struct scoreboard *scb, tcp_seq seqnum) 396 { 397 return SEQ_LT(seqnum, scb->lostseq); 398 } 399 400 /* 401 * True if at least "amount" has been SACKed. Used by Early Retransmit. 402 */ 403 boolean_t 404 tcp_sack_has_sacked(struct scoreboard *scb, u_int amount) 405 { 406 struct sackblock *sb; 407 int bytes_sacked = 0; 408 409 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 410 bytes_sacked += sb->sblk_end - sb->sblk_start; 411 if (bytes_sacked >= amount) 412 return TRUE; 413 } 414 return FALSE; 415 } 416 417 /* 418 * Number of bytes SACKed below seq. 419 */ 420 int 421 tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq) 422 { 423 struct sackblock *sb; 424 int bytes_sacked = 0; 425 426 sb = TAILQ_FIRST(&scb->sackblocks); 427 while (sb && SEQ_GT(seq, sb->sblk_start)) { 428 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start; 429 sb = TAILQ_NEXT(sb, sblk_list); 430 } 431 return bytes_sacked; 432 } 433 434 /* 435 * Return estimate of the number of bytes outstanding in the network. 436 */ 437 uint32_t 438 tcp_sack_compute_pipe(struct tcpcb *tp) 439 { 440 struct scoreboard *scb = &tp->scb; 441 struct sackblock *sb; 442 int nlost, nretransmitted; 443 tcp_seq end; 444 445 nlost = tp->snd_max - scb->lostseq; 446 nretransmitted = tp->rexmt_high - tp->snd_una; 447 448 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 449 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) { 450 end = seq_min(sb->sblk_end, tp->rexmt_high); 451 nretransmitted -= end - sb->sblk_start; 452 } 453 if (SEQ_GEQ(sb->sblk_start, scb->lostseq)) 454 nlost -= sb->sblk_end - sb->sblk_start; 455 } 456 457 return (nlost + nretransmitted); 458 } 459 460 /* 461 * Return the sequence number and length of the next segment to transmit 462 * when in Fast Recovery. 463 */ 464 boolean_t 465 tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen, 466 boolean_t *lostdup) 467 { 468 struct scoreboard *scb = &tp->scb; 469 struct socket *so = tp->t_inpcb->inp_socket; 470 struct sackblock *sb; 471 const struct sackblock *lastblock = 472 TAILQ_LAST(&scb->sackblocks, sackblock_list); 473 tcp_seq torexmt; 474 long len, off; 475 476 /* skip SACKed data */ 477 tcp_sack_skip_sacked(scb, &tp->rexmt_high); 478 479 /* Look for lost data. */ 480 torexmt = tp->rexmt_high; 481 *lostdup = FALSE; 482 if (lastblock != NULL) { 483 if (SEQ_LT(torexmt, lastblock->sblk_end) && 484 scb_islost(scb, torexmt)) { 485 sendunsacked: 486 *nextrexmt = torexmt; 487 /* If the left-hand edge has been SACKed, pull it in. */ 488 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb)) 489 *plen = sb->sblk_start - torexmt; 490 else 491 *plen = tp->t_maxseg; 492 return TRUE; 493 } 494 } 495 496 /* See if unsent data available within send window. */ 497 off = tp->snd_max - tp->snd_una; 498 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off; 499 if (len > 0) { 500 *nextrexmt = tp->snd_max; /* Send new data. */ 501 *plen = tp->t_maxseg; 502 return TRUE; 503 } 504 505 /* We're less certain this data has been lost. */ 506 if (lastblock == NULL || SEQ_LT(torexmt, lastblock->sblk_end)) 507 goto sendunsacked; 508 509 return FALSE; 510 } 511 512 /* 513 * Return the next sequence number higher than "*prexmt" that has 514 * not been SACKed. 515 */ 516 void 517 tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt) 518 { 519 struct sackblock *sb; 520 521 /* skip SACKed data */ 522 if (sack_block_lookup(scb, *prexmt, &sb)) 523 *prexmt = sb->sblk_end; 524 } 525 526 #ifdef later 527 void 528 tcp_sack_save_scoreboard(struct scoreboard *scb) 529 { 530 struct scoreboard *scb = &tp->scb; 531 532 scb->sackblocks_prev = scb->sackblocks; 533 TAILQ_INIT(&scb->sackblocks); 534 } 535 536 void 537 tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una, 538 u_int maxseg) 539 { 540 struct sackblock *sb; 541 542 scb->sackblocks = scb->sackblocks_prev; 543 scb->nblocks = 0; 544 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 545 ++scb->nblocks; 546 tcp_sack_ack_blocks(scb, snd_una); 547 scb->lastfound = NULL; 548 } 549 #endif 550 551 #ifdef DEBUG_SACK_HISTORY 552 static void 553 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 554 { 555 int i; 556 static int ndumped; 557 558 /* only need a couple of these to debug most problems */ 559 if (++ndumped > 900) 560 return; 561 562 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory); 563 for (i = 0; i < tp->nsackhistory; ++i) 564 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start, 565 tp->sackhistory[i].rblk_end); 566 kprintf("\n"); 567 } 568 #else 569 static __inline void 570 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 571 { 572 } 573 #endif 574 575 /* 576 * Remove old SACK blocks from the SACK history that have already been ACKed. 577 */ 578 static void 579 tcp_sack_ack_history(struct tcpcb *tp) 580 { 581 int i, nblocks, openslot; 582 583 tcp_sack_dump_history("before tcp_sack_ack_history", tp); 584 nblocks = tp->nsackhistory; 585 for (i = openslot = 0; i < nblocks; ++i) { 586 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) { 587 --tp->nsackhistory; 588 continue; 589 } 590 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt)) 591 tp->sackhistory[i].rblk_start = tp->rcv_nxt; 592 if (i == openslot) 593 ++openslot; 594 else 595 tp->sackhistory[openslot++] = tp->sackhistory[i]; 596 } 597 tcp_sack_dump_history("after tcp_sack_ack_history", tp); 598 KASSERT(openslot == tp->nsackhistory, 599 ("tcp_sack_ack_history miscounted: %d != %d", 600 openslot, tp->nsackhistory)); 601 } 602 603 /* 604 * Add or merge newblock into reported history. 605 * Also remove or update SACK blocks that will be acked. 606 */ 607 static void 608 tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end) 609 { 610 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS]; 611 int i, cindex; 612 613 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp); 614 /* 615 * Six cases: 616 * 0) no overlap 617 * 1) newblock == oldblock 618 * 2) oldblock contains newblock 619 * 3) newblock contains oldblock 620 * 4) tail of oldblock overlaps or abuts start of newblock 621 * 5) tail of newblock overlaps or abuts head of oldblock 622 */ 623 for (i = cindex = 0; i < tp->nsackhistory; ++i) { 624 struct raw_sackblock *oldblock = &tp->sackhistory[i]; 625 tcp_seq old_start = oldblock->rblk_start; 626 tcp_seq old_end = oldblock->rblk_end; 627 628 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) { 629 /* Case 0: no overlap. Copy old block. */ 630 copy[cindex++] = *oldblock; 631 continue; 632 } 633 634 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) { 635 /* Cases 1 & 2. Move block to front of history. */ 636 int j; 637 638 start = old_start; 639 end = old_end; 640 /* no need to check rest of blocks */ 641 for (j = i + 1; j < tp->nsackhistory; ++j) 642 copy[cindex++] = tp->sackhistory[j]; 643 break; 644 } 645 646 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) { 647 /* Case 4: extend start of new block. */ 648 start = old_start; 649 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) { 650 /* Case 5: extend end of new block */ 651 end = old_end; 652 } else { 653 /* Case 3. Delete old block by not copying it. */ 654 KASSERT(SEQ_LEQ(start, old_start) && 655 SEQ_GEQ(end, old_end), 656 ("bad logic: old [%u, %u), new [%u, %u)", 657 old_start, old_end, start, end)); 658 } 659 } 660 661 /* insert new block */ 662 tp->sackhistory[0].rblk_start = start; 663 tp->sackhistory[0].rblk_end = end; 664 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1); 665 for (i = 0; i < cindex; ++i) 666 tp->sackhistory[i + 1] = copy[i]; 667 tp->nsackhistory = cindex + 1; 668 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp); 669 } 670 671 /* 672 * Fill in SACK report to return to data sender. 673 */ 674 void 675 tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen) 676 { 677 u_int optlen = *plen; 678 uint32_t *lp = (uint32_t *)(opt + optlen); 679 uint32_t *olp; 680 tcp_seq hstart = tp->rcv_nxt, hend; 681 int nblocks; 682 683 KASSERT(TCP_MAXOLEN - optlen >= 684 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK, 685 ("no room for SACK header and one block: optlen %d", optlen)); 686 687 olp = lp++; 688 optlen += TCPOLEN_SACK_ALIGNED; 689 690 tcp_sack_ack_history(tp); 691 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) { 692 *lp++ = htonl(tp->reportblk.rblk_start); 693 *lp++ = htonl(tp->reportblk.rblk_end); 694 optlen += TCPOLEN_SACK_BLOCK; 695 hstart = tp->reportblk.rblk_start; 696 hend = tp->reportblk.rblk_end; 697 if (tp->t_flags & TF_ENCLOSESEG) { 698 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK, 699 ("no room for enclosing SACK block: oplen %d", 700 optlen)); 701 *lp++ = htonl(tp->encloseblk.rblk_start); 702 *lp++ = htonl(tp->encloseblk.rblk_end); 703 optlen += TCPOLEN_SACK_BLOCK; 704 hstart = tp->encloseblk.rblk_start; 705 hend = tp->encloseblk.rblk_end; 706 } 707 if (SEQ_GT(hstart, tp->rcv_nxt)) 708 tcp_sack_update_reported_history(tp, hstart, hend); 709 } 710 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) { 711 /* Fill in from left! Walk re-assembly queue. */ 712 struct tseg_qent *q; 713 714 q = LIST_FIRST(&tp->t_segq); 715 while (q != NULL && 716 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 717 *lp++ = htonl(q->tqe_th->th_seq); 718 *lp++ = htonl(q->tqe_th->th_seq + q->tqe_len); 719 optlen += TCPOLEN_SACK_BLOCK; 720 q = LIST_NEXT(q, tqe_q); 721 } 722 } else { 723 int n = 0; 724 725 /* Fill in SACK blocks from right side. */ 726 while (n < tp->nsackhistory && 727 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 728 if (tp->sackhistory[n].rblk_start != hstart) { 729 *lp++ = htonl(tp->sackhistory[n].rblk_start); 730 *lp++ = htonl(tp->sackhistory[n].rblk_end); 731 optlen += TCPOLEN_SACK_BLOCK; 732 } 733 ++n; 734 } 735 } 736 tp->reportblk.rblk_start = tp->reportblk.rblk_end; 737 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT); 738 nblocks = (lp - olp - 1) / 2; 739 *olp = htonl(TCPOPT_SACK_ALIGNED | 740 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK)); 741 *plen = optlen; 742 } 743