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 /* 59 * Implemented: 60 * 61 * RFC 2018 62 * RFC 2883 63 * RFC 3517 64 */ 65 66 struct sackblock { 67 tcp_seq sblk_start; 68 tcp_seq sblk_end; 69 TAILQ_ENTRY(sackblock) sblk_list; 70 }; 71 72 #define MAXSAVEDBLOCKS 8 /* per connection limit */ 73 74 static void insert_block(struct scoreboard *scb, struct sackblock *newblock); 75 static void update_lostseq(struct scoreboard *scb, tcp_seq snd_una, 76 u_int maxseg); 77 78 static MALLOC_DEFINE(M_SACKBLOCK, "sblk", "sackblock struct"); 79 80 /* 81 * Per-tcpcb initialization. 82 */ 83 void 84 tcp_sack_tcpcb_init(struct tcpcb *tp) 85 { 86 struct scoreboard *scb = &tp->scb; 87 88 scb->nblocks = 0; 89 TAILQ_INIT(&scb->sackblocks); 90 scb->lastfound = NULL; 91 } 92 93 /* 94 * Find the SACK block containing or immediately preceding "seq". 95 * The boolean result indicates whether the sequence is actually 96 * contained in the SACK block. 97 */ 98 static boolean_t 99 sack_block_lookup(struct scoreboard *scb, tcp_seq seq, struct sackblock **sb) 100 { 101 struct sackblock *hint = scb->lastfound; 102 struct sackblock *cur, *last, *prev; 103 104 if (TAILQ_EMPTY(&scb->sackblocks)) { 105 *sb = NULL; 106 return FALSE; 107 } 108 109 if (hint == NULL) { 110 /* No hint. Search from start to end. */ 111 cur = TAILQ_FIRST(&scb->sackblocks); 112 last = NULL; 113 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 114 } else { 115 if (SEQ_GEQ(seq, hint->sblk_start)) { 116 /* Search from hint to end of list. */ 117 cur = hint; 118 last = NULL; 119 prev = TAILQ_LAST(&scb->sackblocks, sackblock_list); 120 } else { 121 /* Search from front of list to hint. */ 122 cur = TAILQ_FIRST(&scb->sackblocks); 123 last = hint; 124 prev = TAILQ_PREV(hint, sackblock_list, sblk_list); 125 } 126 } 127 128 do { 129 if (SEQ_GT(cur->sblk_end, seq)) { 130 if (SEQ_GEQ(seq, cur->sblk_start)) { 131 *sb = scb->lastfound = cur; 132 return TRUE; 133 } else { 134 *sb = scb->lastfound = 135 TAILQ_PREV(cur, sackblock_list, sblk_list); 136 return FALSE; 137 } 138 } 139 cur = TAILQ_NEXT(cur, sblk_list); 140 } while (cur != last); 141 142 *sb = scb->lastfound = prev; 143 return FALSE; 144 } 145 146 /* 147 * Allocate a SACK block. 148 */ 149 static __inline struct sackblock * 150 alloc_sackblock(void) 151 { 152 return (kmalloc(sizeof(struct sackblock), M_SACKBLOCK, M_NOWAIT)); 153 } 154 155 /* 156 * Free a SACK block. 157 */ 158 static __inline void 159 free_sackblock(struct sackblock *s) 160 { 161 kfree(s, M_SACKBLOCK); 162 } 163 164 /* 165 * Free up SACK blocks for data that's been acked. 166 */ 167 static void 168 tcp_sack_ack_blocks(struct scoreboard *scb, tcp_seq th_ack) 169 { 170 struct sackblock *sb, *nb; 171 172 sb = TAILQ_FIRST(&scb->sackblocks); 173 while (sb && SEQ_LEQ(sb->sblk_end, th_ack)) { 174 nb = TAILQ_NEXT(sb, sblk_list); 175 if (scb->lastfound == sb) 176 scb->lastfound = NULL; 177 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 178 free_sackblock(sb); 179 --scb->nblocks; 180 KASSERT(scb->nblocks >= 0, 181 ("SACK block count underflow: %d < 0", scb->nblocks)); 182 sb = nb; 183 } 184 if (sb && SEQ_GT(th_ack, sb->sblk_start)) 185 sb->sblk_start = th_ack; /* other side reneged? XXX */ 186 } 187 188 /* 189 * Delete and free SACK blocks saved in scoreboard. 190 */ 191 void 192 tcp_sack_cleanup(struct scoreboard *scb) 193 { 194 struct sackblock *sb, *nb; 195 196 TAILQ_FOREACH_MUTABLE(sb, &scb->sackblocks, sblk_list, nb) { 197 free_sackblock(sb); 198 --scb->nblocks; 199 } 200 KASSERT(scb->nblocks == 0, 201 ("SACK block %d count not zero", scb->nblocks)); 202 TAILQ_INIT(&scb->sackblocks); 203 scb->lastfound = NULL; 204 } 205 206 /* 207 * Returns 0 if not D-SACK block, 208 * 1 if D-SACK, 209 * 2 if duplicate of out-of-order D-SACK block. 210 */ 211 int 212 tcp_sack_ndsack_blocks(struct raw_sackblock *blocks, const int numblocks, 213 tcp_seq snd_una) 214 { 215 if (numblocks == 0) 216 return 0; 217 218 if (SEQ_LT(blocks[0].rblk_start, snd_una)) 219 return 1; 220 221 /* block 0 inside block 1 */ 222 if (numblocks > 1 && 223 SEQ_GEQ(blocks[0].rblk_start, blocks[1].rblk_start) && 224 SEQ_LEQ(blocks[0].rblk_end, blocks[1].rblk_end)) 225 return 2; 226 227 return 0; 228 } 229 230 /* 231 * Update scoreboard on new incoming ACK. 232 */ 233 static void 234 tcp_sack_add_blocks(struct tcpcb *tp, struct tcpopt *to) 235 { 236 const int numblocks = to->to_nsackblocks; 237 struct raw_sackblock *blocks = to->to_sackblocks; 238 struct scoreboard *scb = &tp->scb; 239 struct sackblock *sb; 240 int startblock; 241 int i; 242 243 if (tcp_sack_ndsack_blocks(blocks, numblocks, tp->snd_una) > 0) 244 startblock = 1; 245 else 246 startblock = 0; 247 248 for (i = startblock; i < numblocks; i++) { 249 struct raw_sackblock *newsackblock = &blocks[i]; 250 251 /* don't accept bad SACK blocks */ 252 if (SEQ_GT(newsackblock->rblk_end, tp->snd_max)) { 253 tcpstat.tcps_rcvbadsackopt++; 254 break; /* skip all other blocks */ 255 } 256 tcpstat.tcps_sacksbupdate++; 257 258 sb = alloc_sackblock(); 259 if (sb == NULL) { /* do some sort of cleanup? XXX */ 260 tcpstat.tcps_sacksbfailed++; 261 break; /* just skip rest of blocks */ 262 } 263 sb->sblk_start = newsackblock->rblk_start; 264 sb->sblk_end = newsackblock->rblk_end; 265 if (TAILQ_EMPTY(&scb->sackblocks)) { 266 KASSERT(scb->nblocks == 0, ("emply scb w/ blocks")); 267 scb->nblocks = 1; 268 TAILQ_INSERT_HEAD(&scb->sackblocks, sb, sblk_list); 269 } else { 270 insert_block(scb, sb); 271 } 272 } 273 } 274 275 void 276 tcp_sack_update_scoreboard(struct tcpcb *tp, struct tcpopt *to) 277 { 278 struct scoreboard *scb = &tp->scb; 279 280 tcp_sack_ack_blocks(scb, tp->snd_una); 281 tcp_sack_add_blocks(tp, to); 282 update_lostseq(scb, tp->snd_una, tp->t_maxseg); 283 if (SEQ_LT(tp->rexmt_high, tp->snd_una)) 284 tp->rexmt_high = tp->snd_una; 285 } 286 287 /* 288 * Insert SACK block into sender's scoreboard. 289 */ 290 static void 291 insert_block(struct scoreboard *scb, struct sackblock *newblock) 292 { 293 struct sackblock *sb, *workingblock; 294 boolean_t overlap_front; 295 296 KASSERT(scb->nblocks > 0, ("insert_block() called w/ no blocks")); 297 298 if (scb->nblocks == MAXSAVEDBLOCKS) { 299 /* 300 * Should try to kick out older blocks XXX JH 301 * May be able to coalesce with existing block. 302 * Or, go other way and free all blocks if we hit this limit. 303 */ 304 free_sackblock(newblock); 305 tcpstat.tcps_sacksboverflow++; 306 return; 307 } 308 KASSERT(scb->nblocks < MAXSAVEDBLOCKS, 309 ("too many SACK blocks %d", scb->nblocks)); 310 311 overlap_front = sack_block_lookup(scb, newblock->sblk_start, &sb); 312 313 if (sb == NULL) { 314 workingblock = newblock; 315 TAILQ_INSERT_HEAD(&scb->sackblocks, newblock, sblk_list); 316 ++scb->nblocks; 317 } else { 318 if (overlap_front || sb->sblk_end == newblock->sblk_start) { 319 /* extend old block and discard new one */ 320 workingblock = sb; 321 if (SEQ_GT(newblock->sblk_end, sb->sblk_end)) 322 sb->sblk_end = newblock->sblk_end; 323 free_sackblock(newblock); 324 tcpstat.tcps_sacksbreused++; 325 } else { 326 workingblock = newblock; 327 TAILQ_INSERT_AFTER(&scb->sackblocks, sb, newblock, 328 sblk_list); 329 ++scb->nblocks; 330 } 331 } 332 333 /* Consolidate right-hand side. */ 334 sb = TAILQ_NEXT(workingblock, sblk_list); 335 while (sb != NULL && 336 SEQ_GEQ(workingblock->sblk_end, sb->sblk_end)) { 337 struct sackblock *nextblock; 338 339 nextblock = TAILQ_NEXT(sb, sblk_list); 340 if (scb->lastfound == sb) 341 scb->lastfound = NULL; 342 /* Remove completely overlapped block */ 343 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 344 free_sackblock(sb); 345 --scb->nblocks; 346 KASSERT(scb->nblocks > 0, 347 ("removed overlapped block: %d blocks left", scb->nblocks)); 348 sb = nextblock; 349 } 350 if (sb != NULL && 351 SEQ_GEQ(workingblock->sblk_end, sb->sblk_start)) { 352 /* Extend new block to cover partially overlapped old block. */ 353 workingblock->sblk_end = sb->sblk_end; 354 if (scb->lastfound == sb) 355 scb->lastfound = NULL; 356 TAILQ_REMOVE(&scb->sackblocks, sb, sblk_list); 357 free_sackblock(sb); 358 --scb->nblocks; 359 KASSERT(scb->nblocks > 0, 360 ("removed partial right: %d blocks left", scb->nblocks)); 361 } 362 } 363 364 #ifdef DEBUG_SACK_BLOCKS 365 static void 366 tcp_sack_dump_blocks(struct scoreboard *scb) 367 { 368 struct sackblock *sb; 369 370 kprintf("%d blocks:", scb->nblocks); 371 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 372 kprintf(" [%u, %u)", sb->sblk_start, sb->sblk_end); 373 kprintf("\n"); 374 } 375 #else 376 static __inline void 377 tcp_sack_dump_blocks(struct scoreboard *scb) 378 { 379 } 380 #endif 381 382 /* 383 * Optimization to quickly determine which packets are lost. 384 */ 385 static void 386 update_lostseq(struct scoreboard *scb, tcp_seq snd_una, u_int maxseg) 387 { 388 struct sackblock *sb; 389 int nsackblocks = 0; 390 int bytes_sacked = 0; 391 392 sb = TAILQ_LAST(&scb->sackblocks, sackblock_list); 393 while (sb != NULL) { 394 ++nsackblocks; 395 bytes_sacked += sb->sblk_end - sb->sblk_start; 396 if (nsackblocks == tcprexmtthresh || 397 bytes_sacked >= tcprexmtthresh * maxseg) { 398 scb->lostseq = sb->sblk_start; 399 return; 400 } 401 sb = TAILQ_PREV(sb, sackblock_list, sblk_list); 402 } 403 scb->lostseq = snd_una; 404 } 405 406 /* 407 * Return whether the given sequence number is considered lost. 408 */ 409 static boolean_t 410 scb_islost(struct scoreboard *scb, tcp_seq seqnum) 411 { 412 return SEQ_LT(seqnum, scb->lostseq); 413 } 414 415 /* 416 * True if at least "amount" has been SACKed. Used by Early Retransmit. 417 */ 418 boolean_t 419 tcp_sack_has_sacked(struct scoreboard *scb, u_int amount) 420 { 421 struct sackblock *sb; 422 int bytes_sacked = 0; 423 424 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 425 bytes_sacked += sb->sblk_end - sb->sblk_start; 426 if (bytes_sacked >= amount) 427 return TRUE; 428 } 429 return FALSE; 430 } 431 432 /* 433 * Number of bytes SACKed below seq. 434 */ 435 int 436 tcp_sack_bytes_below(struct scoreboard *scb, tcp_seq seq) 437 { 438 struct sackblock *sb; 439 int bytes_sacked = 0; 440 441 sb = TAILQ_FIRST(&scb->sackblocks); 442 while (sb && SEQ_GT(seq, sb->sblk_start)) { 443 bytes_sacked += seq_min(seq, sb->sblk_end) - sb->sblk_start; 444 sb = TAILQ_NEXT(sb, sblk_list); 445 } 446 return bytes_sacked; 447 } 448 449 /* 450 * Return estimate of the number of bytes outstanding in the network. 451 */ 452 uint32_t 453 tcp_sack_compute_pipe(struct tcpcb *tp) 454 { 455 struct scoreboard *scb = &tp->scb; 456 struct sackblock *sb; 457 int nlost, nretransmitted; 458 tcp_seq end; 459 460 nlost = tp->snd_max - scb->lostseq; 461 nretransmitted = tp->rexmt_high - tp->snd_una; 462 463 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) { 464 if (SEQ_LT(sb->sblk_start, tp->rexmt_high)) { 465 end = seq_min(sb->sblk_end, tp->rexmt_high); 466 nretransmitted -= end - sb->sblk_start; 467 } 468 if (SEQ_GEQ(sb->sblk_start, scb->lostseq)) 469 nlost -= sb->sblk_end - sb->sblk_start; 470 } 471 472 return (nlost + nretransmitted); 473 } 474 475 /* 476 * Return the sequence number and length of the next segment to transmit 477 * when in Fast Recovery. 478 */ 479 boolean_t 480 tcp_sack_nextseg(struct tcpcb *tp, tcp_seq *nextrexmt, uint32_t *plen, 481 boolean_t *lostdup) 482 { 483 struct scoreboard *scb = &tp->scb; 484 struct socket *so = tp->t_inpcb->inp_socket; 485 struct sackblock *sb; 486 const struct sackblock *lastblock = 487 TAILQ_LAST(&scb->sackblocks, sackblock_list); 488 tcp_seq torexmt; 489 long len, off; 490 491 /* skip SACKed data */ 492 tcp_sack_skip_sacked(scb, &tp->rexmt_high); 493 494 /* Look for lost data. */ 495 torexmt = tp->rexmt_high; 496 *lostdup = FALSE; 497 if (lastblock != NULL) { 498 if (SEQ_LT(torexmt, lastblock->sblk_end) && 499 scb_islost(scb, torexmt)) { 500 sendunsacked: 501 *nextrexmt = torexmt; 502 /* If the left-hand edge has been SACKed, pull it in. */ 503 if (sack_block_lookup(scb, torexmt + tp->t_maxseg, &sb)) 504 *plen = sb->sblk_start - torexmt; 505 else 506 *plen = tp->t_maxseg; 507 return TRUE; 508 } 509 } 510 511 /* See if unsent data available within send window. */ 512 off = tp->snd_max - tp->snd_una; 513 len = (long) ulmin(so->so_snd.ssb_cc, tp->snd_wnd) - off; 514 if (len > 0) { 515 *nextrexmt = tp->snd_max; /* Send new data. */ 516 *plen = tp->t_maxseg; 517 return TRUE; 518 } 519 520 /* We're less certain this data has been lost. */ 521 if (lastblock == NULL || SEQ_LT(torexmt, lastblock->sblk_end)) 522 goto sendunsacked; 523 524 return FALSE; 525 } 526 527 /* 528 * Return the next sequence number higher than "*prexmt" that has 529 * not been SACKed. 530 */ 531 void 532 tcp_sack_skip_sacked(struct scoreboard *scb, tcp_seq *prexmt) 533 { 534 struct sackblock *sb; 535 536 /* skip SACKed data */ 537 if (sack_block_lookup(scb, *prexmt, &sb)) 538 *prexmt = sb->sblk_end; 539 } 540 541 #ifdef later 542 void 543 tcp_sack_save_scoreboard(struct scoreboard *scb) 544 { 545 struct scoreboard *scb = &tp->scb; 546 547 scb->sackblocks_prev = scb->sackblocks; 548 TAILQ_INIT(&scb->sackblocks); 549 } 550 551 void 552 tcp_sack_revert_scoreboard(struct scoreboard *scb, tcp_seq snd_una, 553 u_int maxseg) 554 { 555 struct sackblock *sb; 556 557 scb->sackblocks = scb->sackblocks_prev; 558 scb->nblocks = 0; 559 TAILQ_FOREACH(sb, &scb->sackblocks, sblk_list) 560 ++scb->nblocks; 561 tcp_sack_ack_blocks(scb, snd_una); 562 scb->lastfound = NULL; 563 } 564 #endif 565 566 #ifdef DEBUG_SACK_HISTORY 567 static void 568 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 569 { 570 int i; 571 static int ndumped; 572 573 /* only need a couple of these to debug most problems */ 574 if (++ndumped > 900) 575 return; 576 577 kprintf("%s:\tnsackhistory %d: ", msg, tp->nsackhistory); 578 for (i = 0; i < tp->nsackhistory; ++i) 579 kprintf("[%u, %u) ", tp->sackhistory[i].rblk_start, 580 tp->sackhistory[i].rblk_end); 581 kprintf("\n"); 582 } 583 #else 584 static __inline void 585 tcp_sack_dump_history(char *msg, struct tcpcb *tp) 586 { 587 } 588 #endif 589 590 /* 591 * Remove old SACK blocks from the SACK history that have already been ACKed. 592 */ 593 static void 594 tcp_sack_ack_history(struct tcpcb *tp) 595 { 596 int i, nblocks, openslot; 597 598 tcp_sack_dump_history("before tcp_sack_ack_history", tp); 599 nblocks = tp->nsackhistory; 600 for (i = openslot = 0; i < nblocks; ++i) { 601 if (SEQ_LEQ(tp->sackhistory[i].rblk_end, tp->rcv_nxt)) { 602 --tp->nsackhistory; 603 continue; 604 } 605 if (SEQ_LT(tp->sackhistory[i].rblk_start, tp->rcv_nxt)) 606 tp->sackhistory[i].rblk_start = tp->rcv_nxt; 607 if (i == openslot) 608 ++openslot; 609 else 610 tp->sackhistory[openslot++] = tp->sackhistory[i]; 611 } 612 tcp_sack_dump_history("after tcp_sack_ack_history", tp); 613 KASSERT(openslot == tp->nsackhistory, 614 ("tcp_sack_ack_history miscounted: %d != %d", 615 openslot, tp->nsackhistory)); 616 } 617 618 /* 619 * Add or merge newblock into reported history. 620 * Also remove or update SACK blocks that will be acked. 621 */ 622 static void 623 tcp_sack_update_reported_history(struct tcpcb *tp, tcp_seq start, tcp_seq end) 624 { 625 struct raw_sackblock copy[MAX_SACK_REPORT_BLOCKS]; 626 int i, cindex; 627 628 tcp_sack_dump_history("before tcp_sack_update_reported_history", tp); 629 /* 630 * Six cases: 631 * 0) no overlap 632 * 1) newblock == oldblock 633 * 2) oldblock contains newblock 634 * 3) newblock contains oldblock 635 * 4) tail of oldblock overlaps or abuts start of newblock 636 * 5) tail of newblock overlaps or abuts head of oldblock 637 */ 638 for (i = cindex = 0; i < tp->nsackhistory; ++i) { 639 struct raw_sackblock *oldblock = &tp->sackhistory[i]; 640 tcp_seq old_start = oldblock->rblk_start; 641 tcp_seq old_end = oldblock->rblk_end; 642 643 if (SEQ_LT(end, old_start) || SEQ_GT(start, old_end)) { 644 /* Case 0: no overlap. Copy old block. */ 645 copy[cindex++] = *oldblock; 646 continue; 647 } 648 649 if (SEQ_GEQ(start, old_start) && SEQ_LEQ(end, old_end)) { 650 /* Cases 1 & 2. Move block to front of history. */ 651 int j; 652 653 start = old_start; 654 end = old_end; 655 /* no need to check rest of blocks */ 656 for (j = i + 1; j < tp->nsackhistory; ++j) 657 copy[cindex++] = tp->sackhistory[j]; 658 break; 659 } 660 661 if (SEQ_GEQ(old_end, start) && SEQ_LT(old_start, start)) { 662 /* Case 4: extend start of new block. */ 663 start = old_start; 664 } else if (SEQ_GEQ(end, old_start) && SEQ_GT(old_end, end)) { 665 /* Case 5: extend end of new block */ 666 end = old_end; 667 } else { 668 /* Case 3. Delete old block by not copying it. */ 669 KASSERT(SEQ_LEQ(start, old_start) && 670 SEQ_GEQ(end, old_end), 671 ("bad logic: old [%u, %u), new [%u, %u)", 672 old_start, old_end, start, end)); 673 } 674 } 675 676 /* insert new block */ 677 tp->sackhistory[0].rblk_start = start; 678 tp->sackhistory[0].rblk_end = end; 679 cindex = min(cindex, MAX_SACK_REPORT_BLOCKS - 1); 680 for (i = 0; i < cindex; ++i) 681 tp->sackhistory[i + 1] = copy[i]; 682 tp->nsackhistory = cindex + 1; 683 tcp_sack_dump_history("after tcp_sack_update_reported_history", tp); 684 } 685 686 /* 687 * Fill in SACK report to return to data sender. 688 */ 689 void 690 tcp_sack_fill_report(struct tcpcb *tp, u_char *opt, u_int *plen) 691 { 692 u_int optlen = *plen; 693 uint32_t *lp = (uint32_t *)(opt + optlen); 694 uint32_t *olp; 695 tcp_seq hstart = tp->rcv_nxt, hend; 696 int nblocks; 697 698 KASSERT(TCP_MAXOLEN - optlen >= 699 TCPOLEN_SACK_ALIGNED + TCPOLEN_SACK_BLOCK, 700 ("no room for SACK header and one block: optlen %d", optlen)); 701 702 if (tp->t_flags & TF_DUPSEG) 703 tcpstat.tcps_snddsackopt++; 704 else 705 tcpstat.tcps_sndsackopt++; 706 707 olp = lp++; 708 optlen += TCPOLEN_SACK_ALIGNED; 709 710 tcp_sack_ack_history(tp); 711 if (tp->reportblk.rblk_start != tp->reportblk.rblk_end) { 712 *lp++ = htonl(tp->reportblk.rblk_start); 713 *lp++ = htonl(tp->reportblk.rblk_end); 714 optlen += TCPOLEN_SACK_BLOCK; 715 hstart = tp->reportblk.rblk_start; 716 hend = tp->reportblk.rblk_end; 717 if (tp->t_flags & TF_ENCLOSESEG) { 718 KASSERT(TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK, 719 ("no room for enclosing SACK block: oplen %d", 720 optlen)); 721 *lp++ = htonl(tp->encloseblk.rblk_start); 722 *lp++ = htonl(tp->encloseblk.rblk_end); 723 optlen += TCPOLEN_SACK_BLOCK; 724 hstart = tp->encloseblk.rblk_start; 725 hend = tp->encloseblk.rblk_end; 726 } 727 if (SEQ_GT(hstart, tp->rcv_nxt)) 728 tcp_sack_update_reported_history(tp, hstart, hend); 729 } 730 if (tcp_do_smartsack && (tp->t_flags & TF_SACKLEFT)) { 731 /* Fill in from left! Walk re-assembly queue. */ 732 struct tseg_qent *q; 733 734 q = LIST_FIRST(&tp->t_segq); 735 while (q != NULL && 736 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 737 *lp++ = htonl(q->tqe_th->th_seq); 738 *lp++ = htonl(q->tqe_th->th_seq + q->tqe_len); 739 optlen += TCPOLEN_SACK_BLOCK; 740 q = LIST_NEXT(q, tqe_q); 741 } 742 } else { 743 int n = 0; 744 745 /* Fill in SACK blocks from right side. */ 746 while (n < tp->nsackhistory && 747 TCP_MAXOLEN - optlen >= TCPOLEN_SACK_BLOCK) { 748 if (tp->sackhistory[n].rblk_start != hstart) { 749 *lp++ = htonl(tp->sackhistory[n].rblk_start); 750 *lp++ = htonl(tp->sackhistory[n].rblk_end); 751 optlen += TCPOLEN_SACK_BLOCK; 752 } 753 ++n; 754 } 755 } 756 tp->reportblk.rblk_start = tp->reportblk.rblk_end; 757 tp->t_flags &= ~(TF_DUPSEG | TF_ENCLOSESEG | TF_SACKLEFT); 758 nblocks = (lp - olp - 1) / 2; 759 *olp = htonl(TCPOPT_SACK_ALIGNED | 760 (TCPOLEN_SACK + nblocks * TCPOLEN_SACK_BLOCK)); 761 *plen = optlen; 762 } 763